Add Picture Streams architecture with postprocessing templates and stream test UI

Introduce Picture Stream abstraction that separates the capture pipeline into
composable layers: raw streams (display + capture engine + FPS) and processed
streams (source stream + postprocessing template). Devices reference a picture
stream instead of managing individual capture settings.

- Add PictureStream and PostprocessingTemplate data models and stores
- Add CRUD API endpoints for picture streams and postprocessing templates
- Add stream chain resolution in ProcessorManager for start_processing
- Add picture stream test endpoint with postprocessing preview support
- Add Stream Settings modal with border_width and interpolation_mode controls
- Add stream test modal with capture preview and performance metrics
- Add full frontend: Picture Streams tab, Processing Templates tab, stream
  selector on device cards, test buttons on stream cards
- Add localization keys for all new features (en, ru)
- Migrate existing devices to picture streams on startup

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

CLAUDE.md

@@ -66,6 +66,16 @@
 ✅ Claude: [now creates the commit]
 ```
 
+## IMPORTANT: Auto-Restart Server on Code Changes
+
+**Whenever server-side Python code is modified** (any file under `/server/src/`), **automatically restart the server** so the changes take effect immediately. Do NOT wait for the user to ask for a restart.
+
+### Restart procedure
+
+1. Stop the running Python process: `powershell -Command "Get-Process -Name python -ErrorAction SilentlyContinue | Stop-Process -Force"`
+2. Start the server: `powershell -Command "Set-Location 'c:\Users\Alexei\Documents\wled-screen-controller\server'; python -m wled_controller.main"` (run in background)
+3. Wait 3 seconds and check startup logs to confirm it's running
+
 ## Project Structure
 
 This is a monorepo containing:

server/src/wled_controller/api/routes.py

@@ -40,6 +40,15 @@ from wled_controller.api.schemas import (
     CaptureImage,
     BorderExtraction,
     PerformanceMetrics,
+    PostprocessingTemplateCreate,
+    PostprocessingTemplateUpdate,
+    PostprocessingTemplateResponse,
+    PostprocessingTemplateListResponse,
+    PictureStreamCreate,
+    PictureStreamUpdate,
+    PictureStreamResponse,
+    PictureStreamListResponse,
+    PictureStreamTestRequest,
 )
 from wled_controller.config import get_config
 from wled_controller.core.processor_manager import ProcessorManager, ProcessingSettings
@@ -49,6 +58,8 @@ from wled_controller.core.calibration import (
 )
 from wled_controller.storage import DeviceStore
 from wled_controller.storage.template_store import TemplateStore
+from wled_controller.storage.postprocessing_template_store import PostprocessingTemplateStore
+from wled_controller.storage.picture_stream_store import PictureStreamStore
 from wled_controller.core.capture_engines import EngineRegistry
 from wled_controller.utils import get_logger
 from wled_controller.core.screen_capture import get_available_displays
@@ -60,6 +71,8 @@ router = APIRouter()
 # Global instances (initialized in main.py)
 _device_store: DeviceStore | None = None
 _template_store: TemplateStore | None = None
+_pp_template_store: PostprocessingTemplateStore | None = None
+_picture_stream_store: PictureStreamStore | None = None
 _processor_manager: ProcessorManager | None = None
 
 
@@ -77,6 +90,20 @@ def get_template_store() -> TemplateStore:
     return _template_store
 
 
+def get_pp_template_store() -> PostprocessingTemplateStore:
+    """Get postprocessing template store dependency."""
+    if _pp_template_store is None:
+        raise RuntimeError("Postprocessing template store not initialized")
+    return _pp_template_store
+
+
+def get_picture_stream_store() -> PictureStreamStore:
+    """Get picture stream store dependency."""
+    if _picture_stream_store is None:
+        raise RuntimeError("Picture stream store not initialized")
+    return _picture_stream_store
+
+
 def get_processor_manager() -> ProcessorManager:
     """Get processor manager dependency."""
     if _processor_manager is None:
@@ -88,12 +115,16 @@ def init_dependencies(
     device_store: DeviceStore,
     template_store: TemplateStore,
     processor_manager: ProcessorManager,
+    pp_template_store: PostprocessingTemplateStore | None = None,
+    picture_stream_store: PictureStreamStore | None = None,
 ):
     """Initialize global dependencies."""
-    global _device_store, _template_store, _processor_manager
+    global _device_store, _template_store, _processor_manager, _pp_template_store, _picture_stream_store
     _device_store = device_store
     _template_store = template_store
     _processor_manager = processor_manager
+    _pp_template_store = pp_template_store
+    _picture_stream_store = picture_stream_store
 
 
 @router.get("/health", response_model=HealthResponse, tags=["Health"])
@@ -230,7 +261,10 @@ async def create_device(
             if all_templates:
                 capture_template_id = all_templates[0].id
             else:
-                capture_template_id = "tpl_mss_default"
+                raise HTTPException(
+                    status_code=500,
+                    detail="No capture templates available. Please create one first."
+                )
 
         # Create device in storage (LED count auto-detected from WLED)
         device = store.create_device(
@@ -260,11 +294,13 @@ async def create_device(
                 display_index=device.settings.display_index,
                 fps=device.settings.fps,
                 border_width=device.settings.border_width,
+                interpolation_mode=device.settings.interpolation_mode,
                 brightness=device.settings.brightness,
                 state_check_interval=device.settings.state_check_interval,
             ),
             calibration=CalibrationSchema(**calibration_to_dict(device.calibration)),
             capture_template_id=device.capture_template_id,
+            picture_stream_id=device.picture_stream_id,
             created_at=device.created_at,
             updated_at=device.updated_at,
         )
@@ -300,6 +336,7 @@ async def list_devices(
                 ),
                 calibration=CalibrationSchema(**calibration_to_dict(device.calibration)),
                 capture_template_id=device.capture_template_id,
+                picture_stream_id=device.picture_stream_id,
                 created_at=device.created_at,
                 updated_at=device.updated_at,
             )
@@ -359,8 +396,12 @@ async def update_device(
 ):
     """Update device information."""
     try:
-        # Check if template changed and device is processing (for hot-swap)
+        # Check if stream or template changed and device is processing (for hot-swap)
         old_device = store.get_device(device_id)
+        stream_changed = (
+            update_data.picture_stream_id is not None
+            and update_data.picture_stream_id != old_device.picture_stream_id
+        )
         template_changed = (
             update_data.capture_template_id is not None
             and update_data.capture_template_id != old_device.capture_template_id
@@ -374,16 +415,17 @@ async def update_device(
             url=update_data.url,
             enabled=update_data.enabled,
             capture_template_id=update_data.capture_template_id,
+            picture_stream_id=update_data.picture_stream_id,
         )
 
-        # Hot-swap: If template changed and device was processing, restart it
-        if template_changed and was_processing:
-            logger.info(f"Hot-swapping template for device {device_id}")
+        # Hot-swap: If stream/template changed and device was processing, restart it
+        if (stream_changed or template_changed) and was_processing:
+            logger.info(f"Hot-swapping stream/template for device {device_id}")
             try:
                 # Stop current processing
                 await manager.stop_processing(device_id)
 
-                # Update processor with new template
+                # Update processor with new settings
                 manager.remove_device(device_id)
                 manager.add_device(
                     device_id=device.id,
@@ -392,11 +434,12 @@ async def update_device(
                     settings=device.settings,
                     calibration=device.calibration,
                     capture_template_id=device.capture_template_id,
+                    picture_stream_id=device.picture_stream_id,
                 )
 
                 # Restart processing
                 await manager.start_processing(device_id)
-                logger.info(f"Successfully hot-swapped template for device {device_id}")
+                logger.info(f"Successfully hot-swapped stream/template for device {device_id}")
 
             except Exception as e:
                 logger.error(f"Error during template hot-swap: {e}")
@@ -413,11 +456,13 @@ async def update_device(
                 display_index=device.settings.display_index,
                 fps=device.settings.fps,
                 border_width=device.settings.border_width,
+                interpolation_mode=device.settings.interpolation_mode,
                 brightness=device.settings.brightness,
                 state_check_interval=device.settings.state_check_interval,
             ),
             calibration=CalibrationSchema(**calibration_to_dict(device.calibration)),
             capture_template_id=device.capture_template_id,
+            picture_stream_id=device.picture_stream_id,
             created_at=device.created_at,
             updated_at=device.updated_at,
         )
@@ -540,6 +585,7 @@ async def get_settings(
         display_index=device.settings.display_index,
         fps=device.settings.fps,
         border_width=device.settings.border_width,
+        interpolation_mode=device.settings.interpolation_mode,
         brightness=device.settings.brightness,
         state_check_interval=device.settings.state_check_interval,
     )
@@ -553,16 +599,28 @@ async def update_settings(
     store: DeviceStore = Depends(get_device_store),
     manager: ProcessorManager = Depends(get_processor_manager),
 ):
-    """Update processing settings for a device."""
+    """Update processing settings for a device.
+
+    Merges with existing settings so callers can send partial updates.
+    """
     try:
-        # Create ProcessingSettings from schema
+        # Get existing device to merge settings
+        device = store.get_device(device_id)
+        if not device:
+            raise HTTPException(status_code=404, detail=f"Device {device_id} not found")
+
+        existing = device.settings
+
+        # Merge: use new values where provided, keep existing otherwise
         new_settings = ProcessingSettings(
             display_index=settings.display_index,
             fps=settings.fps,
             border_width=settings.border_width,
-            brightness=settings.color_correction.brightness if settings.color_correction else 1.0,
-            gamma=settings.color_correction.gamma if settings.color_correction else 2.2,
-            saturation=settings.color_correction.saturation if settings.color_correction else 1.0,
+            interpolation_mode=settings.interpolation_mode,
+            brightness=settings.color_correction.brightness if settings.color_correction else existing.brightness,
+            gamma=settings.color_correction.gamma if settings.color_correction else existing.gamma,
+            saturation=settings.color_correction.saturation if settings.color_correction else existing.saturation,
+            smoothing=existing.smoothing,
             state_check_interval=settings.state_check_interval,
         )
 
@@ -580,6 +638,7 @@ async def update_settings(
             display_index=device.settings.display_index,
             fps=device.settings.fps,
             border_width=device.settings.border_width,
+            interpolation_mode=device.settings.interpolation_mode,
             brightness=device.settings.brightness,
             state_check_interval=device.settings.state_check_interval,
         )
@@ -736,7 +795,7 @@ async def list_templates(
                 name=t.name,
                 engine_type=t.engine_type,
                 engine_config=t.engine_config,
-                is_default=t.is_default,
+
                 created_at=t.created_at,
                 updated_at=t.updated_at,
                 description=t.description,
@@ -774,7 +833,7 @@ async def create_template(
             name=template.name,
             engine_type=template.engine_type,
             engine_config=template.engine_config,
-            is_default=template.is_default,
+
             created_at=template.created_at,
             updated_at=template.updated_at,
             description=template.description,
@@ -804,7 +863,6 @@ async def get_template(
         name=template.name,
         engine_type=template.engine_type,
         engine_config=template.engine_config,
-        is_default=template.is_default,
         created_at=template.created_at,
         updated_at=template.updated_at,
         description=template.description,
@@ -833,7 +891,7 @@ async def update_template(
             name=template.name,
             engine_type=template.engine_type,
             engine_config=template.engine_config,
-            is_default=template.is_default,
+
             created_at=template.created_at,
             updated_at=template.updated_at,
             description=template.description,
@@ -1038,3 +1096,441 @@ async def test_template(
                 engine.cleanup()
             except Exception as e:
                 logger.error(f"Error cleaning up test engine: {e}")
+
+
+# ===== POSTPROCESSING TEMPLATE ENDPOINTS =====
+
+def _pp_template_to_response(t) -> PostprocessingTemplateResponse:
+    """Convert a PostprocessingTemplate to its API response."""
+    return PostprocessingTemplateResponse(
+        id=t.id,
+        name=t.name,
+        gamma=t.gamma,
+        saturation=t.saturation,
+        brightness=t.brightness,
+        smoothing=t.smoothing,
+        created_at=t.created_at,
+        updated_at=t.updated_at,
+        description=t.description,
+    )
+
+
+@router.get("/api/v1/postprocessing-templates", response_model=PostprocessingTemplateListResponse, tags=["Postprocessing Templates"])
+async def list_pp_templates(
+    _auth: AuthRequired,
+    store: PostprocessingTemplateStore = Depends(get_pp_template_store),
+):
+    """List all postprocessing templates."""
+    try:
+        templates = store.get_all_templates()
+        responses = [_pp_template_to_response(t) for t in templates]
+        return PostprocessingTemplateListResponse(templates=responses, count=len(responses))
+    except Exception as e:
+        logger.error(f"Failed to list postprocessing templates: {e}")
+        raise HTTPException(status_code=500, detail=str(e))
+
+
+@router.post("/api/v1/postprocessing-templates", response_model=PostprocessingTemplateResponse, tags=["Postprocessing Templates"], status_code=201)
+async def create_pp_template(
+    data: PostprocessingTemplateCreate,
+    _auth: AuthRequired,
+    store: PostprocessingTemplateStore = Depends(get_pp_template_store),
+):
+    """Create a new postprocessing template."""
+    try:
+        template = store.create_template(
+            name=data.name,
+            gamma=data.gamma,
+            saturation=data.saturation,
+            brightness=data.brightness,
+            smoothing=data.smoothing,
+            description=data.description,
+        )
+        return _pp_template_to_response(template)
+    except ValueError as e:
+        raise HTTPException(status_code=400, detail=str(e))
+    except Exception as e:
+        logger.error(f"Failed to create postprocessing template: {e}")
+        raise HTTPException(status_code=500, detail=str(e))
+
+
+@router.get("/api/v1/postprocessing-templates/{template_id}", response_model=PostprocessingTemplateResponse, tags=["Postprocessing Templates"])
+async def get_pp_template(
+    template_id: str,
+    _auth: AuthRequired,
+    store: PostprocessingTemplateStore = Depends(get_pp_template_store),
+):
+    """Get postprocessing template by ID."""
+    try:
+        template = store.get_template(template_id)
+        return _pp_template_to_response(template)
+    except ValueError:
+        raise HTTPException(status_code=404, detail=f"Postprocessing template {template_id} not found")
+
+
+@router.put("/api/v1/postprocessing-templates/{template_id}", response_model=PostprocessingTemplateResponse, tags=["Postprocessing Templates"])
+async def update_pp_template(
+    template_id: str,
+    data: PostprocessingTemplateUpdate,
+    _auth: AuthRequired,
+    store: PostprocessingTemplateStore = Depends(get_pp_template_store),
+):
+    """Update a postprocessing template."""
+    try:
+        template = store.update_template(
+            template_id=template_id,
+            name=data.name,
+            gamma=data.gamma,
+            saturation=data.saturation,
+            brightness=data.brightness,
+            smoothing=data.smoothing,
+            description=data.description,
+        )
+        return _pp_template_to_response(template)
+    except ValueError as e:
+        raise HTTPException(status_code=400, detail=str(e))
+    except Exception as e:
+        logger.error(f"Failed to update postprocessing template: {e}")
+        raise HTTPException(status_code=500, detail=str(e))
+
+
+@router.delete("/api/v1/postprocessing-templates/{template_id}", status_code=204, tags=["Postprocessing Templates"])
+async def delete_pp_template(
+    template_id: str,
+    _auth: AuthRequired,
+    store: PostprocessingTemplateStore = Depends(get_pp_template_store),
+    stream_store: PictureStreamStore = Depends(get_picture_stream_store),
+):
+    """Delete a postprocessing template."""
+    try:
+        # Check if any picture stream references this template
+        if store.is_referenced_by(template_id, stream_store):
+            raise HTTPException(
+                status_code=409,
+                detail="Cannot delete postprocessing template: it is referenced by one or more picture streams. "
+                       "Please reassign those streams before deleting.",
+            )
+        store.delete_template(template_id)
+    except HTTPException:
+        raise
+    except ValueError as e:
+        raise HTTPException(status_code=400, detail=str(e))
+    except Exception as e:
+        logger.error(f"Failed to delete postprocessing template: {e}")
+        raise HTTPException(status_code=500, detail=str(e))
+
+
+# ===== PICTURE STREAM ENDPOINTS =====
+
+def _stream_to_response(s) -> PictureStreamResponse:
+    """Convert a PictureStream to its API response."""
+    return PictureStreamResponse(
+        id=s.id,
+        name=s.name,
+        stream_type=s.stream_type,
+        display_index=s.display_index,
+        capture_template_id=s.capture_template_id,
+        target_fps=s.target_fps,
+        source_stream_id=s.source_stream_id,
+        postprocessing_template_id=s.postprocessing_template_id,
+        created_at=s.created_at,
+        updated_at=s.updated_at,
+        description=s.description,
+    )
+
+
+@router.get("/api/v1/picture-streams", response_model=PictureStreamListResponse, tags=["Picture Streams"])
+async def list_picture_streams(
+    _auth: AuthRequired,
+    store: PictureStreamStore = Depends(get_picture_stream_store),
+):
+    """List all picture streams."""
+    try:
+        streams = store.get_all_streams()
+        responses = [_stream_to_response(s) for s in streams]
+        return PictureStreamListResponse(streams=responses, count=len(responses))
+    except Exception as e:
+        logger.error(f"Failed to list picture streams: {e}")
+        raise HTTPException(status_code=500, detail=str(e))
+
+
+@router.post("/api/v1/picture-streams", response_model=PictureStreamResponse, tags=["Picture Streams"], status_code=201)
+async def create_picture_stream(
+    data: PictureStreamCreate,
+    _auth: AuthRequired,
+    store: PictureStreamStore = Depends(get_picture_stream_store),
+    template_store: TemplateStore = Depends(get_template_store),
+    pp_store: PostprocessingTemplateStore = Depends(get_pp_template_store),
+):
+    """Create a new picture stream."""
+    try:
+        # Validate referenced entities
+        if data.stream_type == "raw" and data.capture_template_id:
+            try:
+                template_store.get_template(data.capture_template_id)
+            except ValueError:
+                raise HTTPException(
+                    status_code=400,
+                    detail=f"Capture template not found: {data.capture_template_id}",
+                )
+
+        if data.stream_type == "processed" and data.postprocessing_template_id:
+            try:
+                pp_store.get_template(data.postprocessing_template_id)
+            except ValueError:
+                raise HTTPException(
+                    status_code=400,
+                    detail=f"Postprocessing template not found: {data.postprocessing_template_id}",
+                )
+
+        stream = store.create_stream(
+            name=data.name,
+            stream_type=data.stream_type,
+            display_index=data.display_index,
+            capture_template_id=data.capture_template_id,
+            target_fps=data.target_fps,
+            source_stream_id=data.source_stream_id,
+            postprocessing_template_id=data.postprocessing_template_id,
+            description=data.description,
+        )
+        return _stream_to_response(stream)
+    except HTTPException:
+        raise
+    except ValueError as e:
+        raise HTTPException(status_code=400, detail=str(e))
+    except Exception as e:
+        logger.error(f"Failed to create picture stream: {e}")
+        raise HTTPException(status_code=500, detail=str(e))
+
+
+@router.get("/api/v1/picture-streams/{stream_id}", response_model=PictureStreamResponse, tags=["Picture Streams"])
+async def get_picture_stream(
+    stream_id: str,
+    _auth: AuthRequired,
+    store: PictureStreamStore = Depends(get_picture_stream_store),
+):
+    """Get picture stream by ID."""
+    try:
+        stream = store.get_stream(stream_id)
+        return _stream_to_response(stream)
+    except ValueError:
+        raise HTTPException(status_code=404, detail=f"Picture stream {stream_id} not found")
+
+
+@router.put("/api/v1/picture-streams/{stream_id}", response_model=PictureStreamResponse, tags=["Picture Streams"])
+async def update_picture_stream(
+    stream_id: str,
+    data: PictureStreamUpdate,
+    _auth: AuthRequired,
+    store: PictureStreamStore = Depends(get_picture_stream_store),
+):
+    """Update a picture stream."""
+    try:
+        stream = store.update_stream(
+            stream_id=stream_id,
+            name=data.name,
+            display_index=data.display_index,
+            capture_template_id=data.capture_template_id,
+            target_fps=data.target_fps,
+            source_stream_id=data.source_stream_id,
+            postprocessing_template_id=data.postprocessing_template_id,
+            description=data.description,
+        )
+        return _stream_to_response(stream)
+    except ValueError as e:
+        raise HTTPException(status_code=400, detail=str(e))
+    except Exception as e:
+        logger.error(f"Failed to update picture stream: {e}")
+        raise HTTPException(status_code=500, detail=str(e))
+
+
+@router.delete("/api/v1/picture-streams/{stream_id}", status_code=204, tags=["Picture Streams"])
+async def delete_picture_stream(
+    stream_id: str,
+    _auth: AuthRequired,
+    store: PictureStreamStore = Depends(get_picture_stream_store),
+    device_store: DeviceStore = Depends(get_device_store),
+):
+    """Delete a picture stream."""
+    try:
+        # Check if any device references this stream
+        if store.is_referenced_by_device(stream_id, device_store):
+            raise HTTPException(
+                status_code=409,
+                detail="Cannot delete picture stream: it is assigned to one or more devices. "
+                       "Please reassign those devices before deleting.",
+            )
+        store.delete_stream(stream_id)
+    except HTTPException:
+        raise
+    except ValueError as e:
+        raise HTTPException(status_code=400, detail=str(e))
+    except Exception as e:
+        logger.error(f"Failed to delete picture stream: {e}")
+        raise HTTPException(status_code=500, detail=str(e))
+
+
+@router.post("/api/v1/picture-streams/{stream_id}/test", response_model=TemplateTestResponse, tags=["Picture Streams"])
+async def test_picture_stream(
+    stream_id: str,
+    test_request: PictureStreamTestRequest,
+    _auth: AuthRequired,
+    store: PictureStreamStore = Depends(get_picture_stream_store),
+    template_store: TemplateStore = Depends(get_template_store),
+    processor_manager: ProcessorManager = Depends(get_processor_manager),
+    device_store: DeviceStore = Depends(get_device_store),
+    pp_store: PostprocessingTemplateStore = Depends(get_pp_template_store),
+):
+    """Test a picture stream by resolving its chain and running a capture test.
+
+    Resolves the stream chain to the raw stream, captures frames,
+    and returns preview image + performance metrics.
+    For processed streams, applies postprocessing (gamma, saturation, brightness)
+    to the preview image.
+    """
+    engine = None
+    try:
+        # Resolve stream chain
+        try:
+            chain = store.resolve_stream_chain(stream_id)
+        except ValueError as e:
+            raise HTTPException(status_code=400, detail=str(e))
+
+        raw_stream = chain["raw_stream"]
+
+        # Get capture template from raw stream
+        try:
+            capture_template = template_store.get_template(raw_stream.capture_template_id)
+        except ValueError:
+            raise HTTPException(
+                status_code=400,
+                detail=f"Capture template not found: {raw_stream.capture_template_id}",
+            )
+
+        display_index = raw_stream.display_index
+
+        # Validate engine
+        if capture_template.engine_type not in EngineRegistry.get_available_engines():
+            raise HTTPException(
+                status_code=400,
+                detail=f"Engine '{capture_template.engine_type}' is not available on this system",
+            )
+
+        # Check display lock
+        locked_device_id = processor_manager.get_display_lock_info(display_index)
+        if locked_device_id:
+            try:
+                device = device_store.get_device(locked_device_id)
+                device_name = device.name
+            except Exception:
+                device_name = locked_device_id
+            raise HTTPException(
+                status_code=409,
+                detail=f"Display {display_index} is currently being captured by device '{device_name}'. "
+                       f"Please stop the device processing before testing.",
+            )
+
+        # Create engine and run test
+        engine = EngineRegistry.create_engine(capture_template.engine_type, capture_template.engine_config)
+
+        logger.info(f"Starting {test_request.capture_duration}s stream test for {stream_id}")
+
+        frame_count = 0
+        total_capture_time = 0.0
+        last_frame = None
+
+        start_time = time.perf_counter()
+        end_time = start_time + test_request.capture_duration
+
+        while time.perf_counter() < end_time:
+            capture_start = time.perf_counter()
+            screen_capture = engine.capture_display(display_index)
+            capture_elapsed = time.perf_counter() - capture_start
+
+            total_capture_time += capture_elapsed
+            frame_count += 1
+            last_frame = screen_capture
+
+        actual_duration = time.perf_counter() - start_time
+
+        if last_frame is None:
+            raise RuntimeError("No frames captured during test")
+
+        # Convert to PIL Image
+        if isinstance(last_frame.image, np.ndarray):
+            pil_image = Image.fromarray(last_frame.image)
+        else:
+            raise ValueError("Unexpected image format from engine")
+
+        # Create thumbnail
+        thumbnail_width = 640
+        aspect_ratio = pil_image.height / pil_image.width
+        thumbnail_height = int(thumbnail_width * aspect_ratio)
+        thumbnail = pil_image.copy()
+        thumbnail.thumbnail((thumbnail_width, thumbnail_height), Image.Resampling.LANCZOS)
+
+        # Apply postprocessing to preview if this is a processed stream
+        pp_template_ids = chain["postprocessing_template_ids"]
+        if pp_template_ids:
+            try:
+                pp = pp_store.get_template(pp_template_ids[0])
+                img_array = np.array(thumbnail, dtype=np.float32) / 255.0
+
+                if pp.brightness != 1.0:
+                    img_array *= pp.brightness
+
+                if pp.saturation != 1.0:
+                    luminance = np.dot(img_array[..., :3], [0.299, 0.587, 0.114])
+                    luminance = luminance[..., np.newaxis]
+                    img_array[..., :3] = luminance + (img_array[..., :3] - luminance) * pp.saturation
+
+                if pp.gamma != 1.0:
+                    img_array = np.power(np.clip(img_array, 0, 1), 1.0 / pp.gamma)
+
+                img_array = np.clip(img_array * 255.0, 0, 255).astype(np.uint8)
+                thumbnail = Image.fromarray(img_array)
+            except ValueError:
+                logger.warning(f"PP template {pp_template_ids[0]} not found, skipping postprocessing preview")
+
+        img_buffer = io.BytesIO()
+        thumbnail.save(img_buffer, format='JPEG', quality=85)
+        img_buffer.seek(0)
+        full_capture_b64 = base64.b64encode(img_buffer.getvalue()).decode('utf-8')
+        full_capture_data_uri = f"data:image/jpeg;base64,{full_capture_b64}"
+
+        actual_fps = frame_count / actual_duration if actual_duration > 0 else 0
+        avg_capture_time_ms = (total_capture_time / frame_count * 1000) if frame_count > 0 else 0
+        width, height = pil_image.size
+
+        return TemplateTestResponse(
+            full_capture=CaptureImage(
+                image=full_capture_data_uri,
+                width=width,
+                height=height,
+                thumbnail_width=thumbnail_width,
+                thumbnail_height=thumbnail_height,
+            ),
+            border_extraction=None,
+            performance=PerformanceMetrics(
+                capture_duration_s=actual_duration,
+                frame_count=frame_count,
+                actual_fps=actual_fps,
+                avg_capture_time_ms=avg_capture_time_ms,
+            ),
+        )
+
+    except HTTPException:
+        raise
+    except ValueError as e:
+        raise HTTPException(status_code=400, detail=str(e))
+    except RuntimeError as e:
+        raise HTTPException(status_code=500, detail=f"Engine error: {str(e)}")
+    except Exception as e:
+        logger.error(f"Failed to test picture stream: {e}", exc_info=True)
+        raise HTTPException(status_code=500, detail=str(e))
+    finally:
+        if engine:
+            try:
+                engine.cleanup()
+            except Exception as e:
+                logger.error(f"Error cleaning up test engine: {e}")

server/src/wled_controller/api/schemas.py

@@ -64,7 +64,8 @@ class DeviceUpdate(BaseModel):
     name: Optional[str] = Field(None, description="Device name", min_length=1, max_length=100)
     url: Optional[str] = Field(None, description="WLED device URL")
     enabled: Optional[bool] = Field(None, description="Whether device is enabled")
-    capture_template_id: Optional[str] = Field(None, description="Capture template ID")
+    capture_template_id: Optional[str] = Field(None, description="Capture template ID (legacy)")
+    picture_stream_id: Optional[str] = Field(None, description="Picture stream ID")
 
 
 class ColorCorrection(BaseModel):
@@ -81,6 +82,7 @@ class ProcessingSettings(BaseModel):
     display_index: int = Field(default=0, description="Display to capture", ge=0)
     fps: int = Field(default=30, description="Target frames per second", ge=10, le=90)
     border_width: int = Field(default=10, description="Border width in pixels", ge=1, le=100)
+    interpolation_mode: str = Field(default="average", description="LED color interpolation mode (average, median, dominant)")
     brightness: float = Field(default=1.0, description="Global brightness (0.0-1.0)", ge=0.0, le=1.0)
     state_check_interval: int = Field(
         default=DEFAULT_STATE_CHECK_INTERVAL, ge=5, le=600,
@@ -155,7 +157,8 @@ class DeviceResponse(BaseModel):
     )
     settings: ProcessingSettings = Field(description="Processing settings")
     calibration: Optional[Calibration] = Field(None, description="Calibration configuration")
-    capture_template_id: str = Field(description="ID of assigned capture template")
+    capture_template_id: str = Field(description="ID of assigned capture template (legacy)")
+    picture_stream_id: str = Field(default="", description="ID of assigned picture stream")
     created_at: datetime = Field(description="Creation timestamp")
     updated_at: datetime = Field(description="Last update timestamp")
 
@@ -242,7 +245,6 @@ class TemplateResponse(BaseModel):
     name: str = Field(description="Template name")
     engine_type: str = Field(description="Engine type identifier")
     engine_config: Dict = Field(description="Engine-specific configuration")
-    is_default: bool = Field(description="Whether this is a system default template")
     created_at: datetime = Field(description="Creation timestamp")
     updated_at: datetime = Field(description="Last update timestamp")
     description: Optional[str] = Field(None, description="Template description")
@@ -321,3 +323,105 @@ class TemplateTestResponse(BaseModel):
     full_capture: CaptureImage = Field(description="Full screen capture with thumbnail")
     border_extraction: Optional[BorderExtraction] = Field(None, description="Extracted border images (deprecated)")
     performance: PerformanceMetrics = Field(description="Performance metrics")
+
+
+# Postprocessing Template Schemas
+
+class PostprocessingTemplateCreate(BaseModel):
+    """Request to create a postprocessing template."""
+
+    name: str = Field(description="Template name", min_length=1, max_length=100)
+    gamma: float = Field(default=2.2, description="Gamma correction", ge=0.1, le=5.0)
+    saturation: float = Field(default=1.0, description="Saturation multiplier", ge=0.0, le=2.0)
+    brightness: float = Field(default=1.0, description="Brightness multiplier", ge=0.0, le=1.0)
+    smoothing: float = Field(default=0.3, description="Temporal smoothing factor", ge=0.0, le=1.0)
+    description: Optional[str] = Field(None, description="Template description", max_length=500)
+
+
+class PostprocessingTemplateUpdate(BaseModel):
+    """Request to update a postprocessing template."""
+
+    name: Optional[str] = Field(None, description="Template name", min_length=1, max_length=100)
+    gamma: Optional[float] = Field(None, description="Gamma correction", ge=0.1, le=5.0)
+    saturation: Optional[float] = Field(None, description="Saturation multiplier", ge=0.0, le=2.0)
+    brightness: Optional[float] = Field(None, description="Brightness multiplier", ge=0.0, le=1.0)
+    smoothing: Optional[float] = Field(None, description="Temporal smoothing factor", ge=0.0, le=1.0)
+    description: Optional[str] = Field(None, description="Template description", max_length=500)
+
+
+class PostprocessingTemplateResponse(BaseModel):
+    """Postprocessing template information response."""
+
+    id: str = Field(description="Template ID")
+    name: str = Field(description="Template name")
+    gamma: float = Field(description="Gamma correction")
+    saturation: float = Field(description="Saturation multiplier")
+    brightness: float = Field(description="Brightness multiplier")
+    smoothing: float = Field(description="Temporal smoothing factor")
+    created_at: datetime = Field(description="Creation timestamp")
+    updated_at: datetime = Field(description="Last update timestamp")
+    description: Optional[str] = Field(None, description="Template description")
+
+
+class PostprocessingTemplateListResponse(BaseModel):
+    """List of postprocessing templates response."""
+
+    templates: List[PostprocessingTemplateResponse] = Field(description="List of postprocessing templates")
+    count: int = Field(description="Number of templates")
+
+
+# Picture Stream Schemas
+
+class PictureStreamCreate(BaseModel):
+    """Request to create a picture stream."""
+
+    name: str = Field(description="Stream name", min_length=1, max_length=100)
+    stream_type: Literal["raw", "processed"] = Field(description="Stream type")
+    display_index: Optional[int] = Field(None, description="Display index (raw streams)", ge=0)
+    capture_template_id: Optional[str] = Field(None, description="Capture template ID (raw streams)")
+    target_fps: Optional[int] = Field(None, description="Target FPS (raw streams)", ge=10, le=90)
+    source_stream_id: Optional[str] = Field(None, description="Source stream ID (processed streams)")
+    postprocessing_template_id: Optional[str] = Field(None, description="Postprocessing template ID (processed streams)")
+    description: Optional[str] = Field(None, description="Stream description", max_length=500)
+
+
+class PictureStreamUpdate(BaseModel):
+    """Request to update a picture stream."""
+
+    name: Optional[str] = Field(None, description="Stream name", min_length=1, max_length=100)
+    display_index: Optional[int] = Field(None, description="Display index (raw streams)", ge=0)
+    capture_template_id: Optional[str] = Field(None, description="Capture template ID (raw streams)")
+    target_fps: Optional[int] = Field(None, description="Target FPS (raw streams)", ge=10, le=90)
+    source_stream_id: Optional[str] = Field(None, description="Source stream ID (processed streams)")
+    postprocessing_template_id: Optional[str] = Field(None, description="Postprocessing template ID (processed streams)")
+    description: Optional[str] = Field(None, description="Stream description", max_length=500)
+
+
+class PictureStreamResponse(BaseModel):
+    """Picture stream information response."""
+
+    id: str = Field(description="Stream ID")
+    name: str = Field(description="Stream name")
+    stream_type: str = Field(description="Stream type (raw or processed)")
+    display_index: Optional[int] = Field(None, description="Display index")
+    capture_template_id: Optional[str] = Field(None, description="Capture template ID")
+    target_fps: Optional[int] = Field(None, description="Target FPS")
+    source_stream_id: Optional[str] = Field(None, description="Source stream ID")
+    postprocessing_template_id: Optional[str] = Field(None, description="Postprocessing template ID")
+    created_at: datetime = Field(description="Creation timestamp")
+    updated_at: datetime = Field(description="Last update timestamp")
+    description: Optional[str] = Field(None, description="Stream description")
+
+
+class PictureStreamListResponse(BaseModel):
+    """List of picture streams response."""
+
+    streams: List[PictureStreamResponse] = Field(description="List of picture streams")
+    count: int = Field(description="Number of streams")
+
+
+class PictureStreamTestRequest(BaseModel):
+    """Request to test a picture stream."""
+
+    capture_duration: float = Field(default=5.0, ge=1.0, le=30.0, description="Duration to capture in seconds")
+    border_width: int = Field(default=10, ge=1, le=100, description="Border width in pixels for preview")

server/src/wled_controller/config.py

@@ -55,6 +55,8 @@ class StorageConfig(BaseSettings):
 
     devices_file: str = "data/devices.json"
     templates_file: str = "data/capture_templates.json"
+    postprocessing_templates_file: str = "data/postprocessing_templates.json"
+    picture_streams_file: str = "data/picture_streams.json"
 
 
 class LoggingConfig(BaseSettings):

server/src/wled_controller/core/capture_engines/base.py

@@ -39,6 +39,7 @@ class CaptureEngine(ABC):
     """
 
     ENGINE_TYPE: str = "base"  # Override in subclasses
+    ENGINE_PRIORITY: int = 0  # Higher = preferred. Override in subclasses.
 
     def __init__(self, config: Dict[str, Any]):
         """Initialize engine with configuration.

server/src/wled_controller/core/capture_engines/dxcam_engine.py

@@ -1,6 +1,7 @@
 """DXcam-based screen capture engine (Windows only, DXGI Desktop Duplication)."""
 
 import sys
+import time
 from typing import Any, Dict, List
 
 import numpy as np
@@ -26,20 +27,14 @@ class DXcamEngine(CaptureEngine):
     """
 
     ENGINE_TYPE = "dxcam"
+    ENGINE_PRIORITY = 3
 
     def __init__(self, config: Dict[str, Any]):
-        """Initialize DXcam engine.
-
-        Args:
-            config: Engine configuration
-                - device_idx (int): GPU index (default: 0)
-                - output_idx (int|None): Monitor index (default: None = primary)
-                - output_color (str): Color format "RGB" or "BGR" (default: "RGB")
-                - max_buffer_len (int): Frame buffer size (default: 64)
-        """
+        """Initialize DXcam engine."""
         super().__init__(config)
         self._camera = None
         self._dxcam = None
+        self._current_output = None
 
     def initialize(self) -> None:
         """Initialize DXcam capture.
@@ -55,45 +50,61 @@ class DXcamEngine(CaptureEngine):
                 "DXcam not installed. Install with: pip install dxcam"
             )
 
+        self._initialized = True
+        logger.info("DXcam engine initialized")
+
+    def _ensure_camera(self, display_index: int) -> None:
+        """Ensure camera is created for the requested display.
+
+        Creates or recreates the DXcam camera if needed.
+        DXcam caches cameras globally per (device, output). We clear the
+        cache before creating to avoid stale DXGI state from prior requests.
+        """
+        if self._camera and self._current_output == display_index:
+            return
+
+        # Release existing camera
+        if self._camera:
+            try:
+                self._camera.release()
+            except Exception:
+                pass
+            self._camera = None
+
+        # Clear dxcam's global camera cache to avoid stale DXGI state
         try:
-            device_idx = self.config.get("device_idx", 0)
-            output_idx = self.config.get("output_idx", None)
-            output_color = self.config.get("output_color", "RGB")
-            max_buffer_len = self.config.get("max_buffer_len", 64)
+            self._dxcam.__factory.clean_up()
+        except Exception:
+            pass
 
-            self._camera = self._dxcam.create(
-                device_idx=device_idx,
-                output_idx=output_idx,
-                output_color=output_color,
-                max_buffer_len=max_buffer_len,
-            )
+        self._camera = self._dxcam.create(
+            output_idx=display_index,
+            output_color="RGB",
+        )
 
-            if not self._camera:
-                raise RuntimeError("Failed to create DXcam camera instance")
+        if not self._camera:
+            raise RuntimeError(f"Failed to create DXcam camera for display {display_index}")
 
-            # Start the camera to begin capturing
-            self._camera.start()
-
-            self._initialized = True
-            logger.info(
-                f"DXcam engine initialized (device={device_idx}, "
-                f"output={output_idx}, color={output_color})"
-            )
-
-        except Exception as e:
-            raise RuntimeError(f"Failed to initialize DXcam: {e}")
+        self._current_output = display_index
+        logger.info(f"DXcam camera created (output={display_index})")
 
     def cleanup(self) -> None:
         """Cleanup DXcam resources."""
         if self._camera:
             try:
-                # Stop capturing before releasing
-                self._camera.stop()
                 self._camera.release()
             except Exception as e:
                 logger.error(f"Error releasing DXcam camera: {e}")
             self._camera = None
 
+        # Clear dxcam's global cache so next create() gets fresh DXGI state
+        if self._dxcam:
+            try:
+                self._dxcam.__factory.clean_up()
+            except Exception:
+                pass
+
+        self._current_output = None
         self._initialized = False
         logger.info("DXcam engine cleaned up")
 
@@ -118,9 +129,7 @@ class DXcamEngine(CaptureEngine):
             # Get output information from DXcam
             # Note: DXcam doesn't provide comprehensive display enumeration
             # We report the single configured output
-            output_idx = self.config.get("output_idx", 0)
-            if output_idx is None:
-                output_idx = 0
+            output_idx = self._current_output or 0
 
             # DXcam camera has basic output info
             if self._camera and hasattr(self._camera, "width") and hasattr(self._camera, "height"):
@@ -160,41 +169,36 @@ class DXcamEngine(CaptureEngine):
         """Capture display using DXcam.
 
         Args:
-            display_index: Index of display to capture (0-based)
-                Note: DXcam is configured for a specific output, so this
-                should match the configured output_idx
+            display_index: Index of display to capture (0-based).
 
         Returns:
             ScreenCapture object with image data
 
         Raises:
-            ValueError: If display_index doesn't match configured output
             RuntimeError: If capture fails
         """
         # Auto-initialize if not already initialized
         if not self._initialized:
             self.initialize()
 
-        # DXcam is configured for a specific output
-        configured_output = self.config.get("output_idx", 0)
-        if configured_output is None:
-            configured_output = 0
-
-        if display_index != configured_output:
-            raise ValueError(
-                f"DXcam engine is configured for output {configured_output}, "
-                f"cannot capture display {display_index}. Create a new template "
-                f"with output_idx={display_index} to capture this display."
-            )
+        # Ensure camera is ready for the requested display
+        self._ensure_camera(display_index)
 
         try:
-            # Grab frame from DXcam
-            frame = self._camera.grab()
+            # Grab frame from DXcam (one-shot mode, no start() needed).
+            # First grab after create() often returns None as DXGI Desktop
+            # Duplication needs a frame change to capture. Retry a few times.
+            frame = None
+            for attempt in range(5):
+                frame = self._camera.grab()
+                if frame is not None:
+                    break
+                time.sleep(0.05)
 
             if frame is None:
                 raise RuntimeError(
-                    "Failed to capture frame (no new data). This can happen if "
-                    "the screen hasn't changed or if there's a timeout."
+                    "Failed to capture frame after retries. "
+                    "The screen may not have changed or the display is unavailable."
                 )
 
             # DXcam returns numpy array directly in configured color format
@@ -243,9 +247,4 @@ class DXcamEngine(CaptureEngine):
         Returns:
             Default config dict with DXcam options
         """
-        return {
-            "device_idx": 0,  # Primary GPU
-            "output_idx": None,  # Primary monitor (None = auto-select)
-            "output_color": "RGB",  # RGB color format
-            "max_buffer_len": 64,  # Frame buffer size
-        }
+        return {}

server/src/wled_controller/core/capture_engines/factory.py

@@ -1,6 +1,6 @@
 """Engine registry and factory for screen capture engines."""
 
-from typing import Any, Dict, List, Type
+from typing import Any, Dict, List, Optional, Type
 
 from wled_controller.core.capture_engines.base import CaptureEngine
 from wled_controller.utils import get_logger
@@ -85,6 +85,26 @@ class EngineRegistry:
 
         return available
 
+    @classmethod
+    def get_best_available_engine(cls) -> Optional[str]:
+        """Get the highest-priority available engine type.
+
+        Returns:
+            Engine type string, or None if no engines are available.
+        """
+        best_type = None
+        best_priority = -1
+        for engine_type, engine_class in cls._engines.items():
+            try:
+                if engine_class.is_available() and engine_class.ENGINE_PRIORITY > best_priority:
+                    best_priority = engine_class.ENGINE_PRIORITY
+                    best_type = engine_type
+            except Exception as e:
+                logger.error(
+                    f"Error checking availability for engine '{engine_type}': {e}"
+                )
+        return best_type
+
     @classmethod
     def get_all_engines(cls) -> Dict[str, Type[CaptureEngine]]:
         """Get all registered engines (available or not).

server/src/wled_controller/core/capture_engines/mss_engine.py

@@ -26,6 +26,7 @@ class MSSEngine(CaptureEngine):
     """
 
     ENGINE_TYPE = "mss"
+    ENGINE_PRIORITY = 1
 
     def __init__(self, config: Dict[str, Any]):
         """Initialize MSS engine.

server/src/wled_controller/core/capture_engines/wgc_engine.py

@@ -34,6 +34,7 @@ class WGCEngine(CaptureEngine):
     """
 
     ENGINE_TYPE = "wgc"
+    ENGINE_PRIORITY = 2
 
     def __init__(self, config: Dict[str, Any]):
         """Initialize WGC engine.

server/src/wled_controller/core/processor_manager.py

@@ -88,10 +88,11 @@ class ProcessorState:
     led_count: int
     settings: ProcessingSettings
     calibration: CalibrationConfig
-    capture_template_id: str = "tpl_mss_default"  # NEW: template ID for capture engine
+    capture_template_id: str = ""
+    picture_stream_id: str = ""
     wled_client: Optional[WLEDClient] = None
     pixel_mapper: Optional[PixelMapper] = None
-    capture_engine: Optional[CaptureEngine] = None  # NEW: initialized capture engine
+    capture_engine: Optional[CaptureEngine] = None
     is_running: bool = False
     task: Optional[asyncio.Task] = None
     metrics: ProcessingMetrics = field(default_factory=ProcessingMetrics)
@@ -100,16 +101,34 @@ class ProcessorState:
     test_mode_active: bool = False
     test_mode_edges: Dict[str, Tuple[int, int, int]] = field(default_factory=dict)
     health_task: Optional[asyncio.Task] = None
+    # Resolved stream values (populated at start_processing time)
+    resolved_display_index: Optional[int] = None
+    resolved_target_fps: Optional[int] = None
+    resolved_engine_type: Optional[str] = None
+    resolved_engine_config: Optional[dict] = None
+    resolved_gamma: Optional[float] = None
+    resolved_saturation: Optional[float] = None
+    resolved_brightness: Optional[float] = None
+    resolved_smoothing: Optional[float] = None
 
 
 class ProcessorManager:
     """Manages screen processing for multiple WLED devices."""
 
-    def __init__(self):
-        """Initialize processor manager."""
+    def __init__(self, picture_stream_store=None, capture_template_store=None, pp_template_store=None):
+        """Initialize processor manager.
+
+        Args:
+            picture_stream_store: PictureStreamStore instance (for stream resolution)
+            capture_template_store: TemplateStore instance (for engine lookup)
+            pp_template_store: PostprocessingTemplateStore instance (for PP settings)
+        """
         self._processors: Dict[str, ProcessorState] = {}
         self._health_monitoring_active = False
         self._http_client: Optional[httpx.AsyncClient] = None
+        self._picture_stream_store = picture_stream_store
+        self._capture_template_store = capture_template_store
+        self._pp_template_store = pp_template_store
         logger.info("Processor manager initialized")
 
     async def _get_http_client(self) -> httpx.AsyncClient:
@@ -125,7 +144,8 @@ class ProcessorManager:
         led_count: int,
         settings: Optional[ProcessingSettings] = None,
         calibration: Optional[CalibrationConfig] = None,
-        capture_template_id: str = "tpl_mss_default",
+        capture_template_id: str = "",
+        picture_stream_id: str = "",
     ):
         """Add a device for processing.
 
@@ -135,7 +155,8 @@ class ProcessorManager:
             led_count: Number of LEDs
             settings: Processing settings (uses defaults if None)
             calibration: Calibration config (creates default if None)
-            capture_template_id: Template ID for screen capture engine
+            capture_template_id: Legacy template ID for screen capture engine
+            picture_stream_id: Picture stream ID (preferred over capture_template_id)
         """
         if device_id in self._processors:
             raise ValueError(f"Device {device_id} already exists")
@@ -153,6 +174,7 @@ class ProcessorManager:
             settings=settings,
             calibration=calibration,
             capture_template_id=capture_template_id,
+            picture_stream_id=picture_stream_id,
         )
 
         self._processors[device_id] = state
@@ -245,9 +267,81 @@ class ProcessorManager:
 
         logger.info(f"Updated calibration for device {device_id}")
 
+    def _resolve_stream_settings(self, state: ProcessorState):
+        """Resolve picture stream chain to populate resolved_* fields on state.
+
+        If device has a picture_stream_id and stores are available, resolves the
+        stream chain to get display_index, fps, engine type/config, and PP settings.
+        Otherwise falls back to legacy device settings.
+        """
+        if state.picture_stream_id and self._picture_stream_store:
+            try:
+                chain = self._picture_stream_store.resolve_stream_chain(state.picture_stream_id)
+                raw_stream = chain["raw_stream"]
+                pp_template_ids = chain["postprocessing_template_ids"]
+
+                state.resolved_display_index = raw_stream.display_index
+                state.resolved_target_fps = raw_stream.target_fps
+
+                # Resolve capture engine from raw stream's capture template
+                if raw_stream.capture_template_id and self._capture_template_store:
+                    try:
+                        tpl = self._capture_template_store.get_template(raw_stream.capture_template_id)
+                        state.resolved_engine_type = tpl.engine_type
+                        state.resolved_engine_config = tpl.engine_config
+                    except ValueError:
+                        logger.warning(f"Capture template {raw_stream.capture_template_id} not found, using MSS fallback")
+                        state.resolved_engine_type = "mss"
+                        state.resolved_engine_config = {}
+
+                # Resolve postprocessing: use first PP template in chain
+                if pp_template_ids and self._pp_template_store:
+                    try:
+                        pp = self._pp_template_store.get_template(pp_template_ids[0])
+                        state.resolved_gamma = pp.gamma
+                        state.resolved_saturation = pp.saturation
+                        state.resolved_brightness = pp.brightness
+                        state.resolved_smoothing = pp.smoothing
+                    except ValueError:
+                        logger.warning(f"PP template {pp_template_ids[0]} not found, using defaults")
+
+                logger.info(
+                    f"Resolved stream chain for {state.device_id}: "
+                    f"display={state.resolved_display_index}, fps={state.resolved_target_fps}, "
+                    f"engine={state.resolved_engine_type}, pp_templates={len(pp_template_ids)}"
+                )
+                return
+            except ValueError as e:
+                logger.warning(f"Failed to resolve stream {state.picture_stream_id}: {e}, falling back to legacy settings")
+
+        # Fallback: use legacy device settings
+        state.resolved_display_index = state.settings.display_index
+        state.resolved_target_fps = state.settings.fps
+        state.resolved_gamma = state.settings.gamma
+        state.resolved_saturation = state.settings.saturation
+        state.resolved_brightness = state.settings.brightness
+        state.resolved_smoothing = state.settings.smoothing
+
+        # Resolve engine from legacy capture_template_id
+        if state.capture_template_id and self._capture_template_store:
+            try:
+                tpl = self._capture_template_store.get_template(state.capture_template_id)
+                state.resolved_engine_type = tpl.engine_type
+                state.resolved_engine_config = tpl.engine_config
+            except ValueError:
+                logger.warning(f"Capture template {state.capture_template_id} not found, using MSS fallback")
+                state.resolved_engine_type = "mss"
+                state.resolved_engine_config = {}
+        else:
+            state.resolved_engine_type = "mss"
+            state.resolved_engine_config = {}
+
     async def start_processing(self, device_id: str):
         """Start screen processing for a device.
 
+        Resolves the picture stream chain (if assigned) to determine capture engine,
+        display, FPS, and postprocessing settings. Falls back to legacy device settings.
+
         Args:
             device_id: Device identifier
 
@@ -263,9 +357,11 @@ class ProcessorManager:
         if state.is_running:
             raise RuntimeError(f"Processing already running for device {device_id}")
 
+        # Resolve stream settings
+        self._resolve_stream_settings(state)
+
         # Connect to WLED device
         try:
-            # Enable DDP for large LED counts (>500 LEDs)
             use_ddp = state.led_count > 500
             state.wled_client = WLEDClient(state.device_url, use_ddp=use_ddp)
             await state.wled_client.connect()
@@ -276,17 +372,16 @@ class ProcessorManager:
             logger.error(f"Failed to connect to WLED device {device_id}: {e}")
             raise RuntimeError(f"Failed to connect to WLED device: {e}")
 
-        # Initialize capture engine
-        # Phase 2: Use MSS engine for all devices (template integration in Phase 5)
+        # Initialize capture engine from resolved settings
         try:
-            # For now, always use MSS engine (Phase 5 will load from template)
-            engine = EngineRegistry.create_engine("mss", {})
+            engine_type = state.resolved_engine_type or "mss"
+            engine_config = state.resolved_engine_config or {}
+            engine = EngineRegistry.create_engine(engine_type, engine_config)
             engine.initialize()
             state.capture_engine = engine
-            logger.debug(f"Initialized capture engine for device {device_id}: mss")
+            logger.info(f"Initialized capture engine for device {device_id}: {engine_type}")
         except Exception as e:
             logger.error(f"Failed to initialize capture engine for device {device_id}: {e}")
-            # Cleanup WLED client before raising
             if state.wled_client:
                 await state.wled_client.disconnect()
             raise RuntimeError(f"Failed to initialize capture engine: {e}")
@@ -352,18 +447,31 @@ class ProcessorManager:
     async def _processing_loop(self, device_id: str):
         """Main processing loop for a device.
 
-        Args:
-            device_id: Device identifier
+        Uses resolved_* fields from stream resolution for display, FPS,
+        and postprocessing. Falls back to device settings for LED projection
+        parameters (border_width, interpolation_mode) and WLED brightness.
         """
         state = self._processors[device_id]
         settings = state.settings
 
+        # Use resolved values (populated by _resolve_stream_settings)
+        display_index = state.resolved_display_index or settings.display_index
+        target_fps = state.resolved_target_fps or settings.fps
+        gamma = state.resolved_gamma if state.resolved_gamma is not None else settings.gamma
+        saturation = state.resolved_saturation if state.resolved_saturation is not None else settings.saturation
+        pp_brightness = state.resolved_brightness if state.resolved_brightness is not None else settings.brightness
+        smoothing = state.resolved_smoothing if state.resolved_smoothing is not None else settings.smoothing
+
+        # These always come from device settings (LED projection)
+        border_width = settings.border_width
+        wled_brightness = settings.brightness  # WLED hardware brightness
+
         logger.info(
             f"Processing loop started for {device_id} "
-            f"(display={settings.display_index}, fps={settings.fps})"
+            f"(display={display_index}, fps={target_fps})"
         )
 
-        frame_time = 1.0 / settings.fps
+        frame_time = 1.0 / target_fps
         fps_samples = []
 
         try:
@@ -376,39 +484,38 @@ class ProcessorManager:
                     continue
 
                 try:
-                    # Run blocking operations in thread pool to avoid blocking event loop
-                    # Capture screen using engine (blocking I/O)
+                    # Capture screen using engine
                     capture = await asyncio.to_thread(
                         state.capture_engine.capture_display,
-                        settings.display_index
+                        display_index
                     )
 
-                    # Extract border pixels (CPU-intensive)
-                    border_pixels = await asyncio.to_thread(extract_border_pixels, capture, settings.border_width)
+                    # Extract border pixels
+                    border_pixels = await asyncio.to_thread(extract_border_pixels, capture, border_width)
 
-                    # Map to LED colors (CPU-intensive)
+                    # Map to LED colors
                     led_colors = await asyncio.to_thread(state.pixel_mapper.map_border_to_leds, border_pixels)
 
-                    # Apply color correction (CPU-intensive)
+                    # Apply color correction from postprocessing
                     led_colors = await asyncio.to_thread(
                         apply_color_correction,
                         led_colors,
-                        gamma=settings.gamma,
-                        saturation=settings.saturation,
-                        brightness=settings.brightness,
+                        gamma=gamma,
+                        saturation=saturation,
+                        brightness=pp_brightness,
                     )
 
-                    # Apply smoothing (CPU-intensive)
-                    if state.previous_colors and settings.smoothing > 0:
+                    # Apply smoothing from postprocessing
+                    if state.previous_colors and smoothing > 0:
                         led_colors = await asyncio.to_thread(
                             smooth_colors,
                             led_colors,
                             state.previous_colors,
-                            settings.smoothing,
+                            smoothing,
                         )
 
-                    # Send to WLED with brightness
-                    brightness_value = int(settings.brightness * 255)
+                    # Send to WLED with device brightness
+                    brightness_value = int(wled_brightness * 255)
                     await state.wled_client.send_pixels(led_colors, brightness=brightness_value)
 
                     # Update metrics
@@ -468,8 +575,8 @@ class ProcessorManager:
             "device_id": device_id,
             "processing": state.is_running,
             "fps_actual": metrics.fps_actual if state.is_running else None,
-            "fps_target": state.settings.fps,
-            "display_index": state.settings.display_index,
+            "fps_target": state.resolved_target_fps or state.settings.fps,
+            "display_index": state.resolved_display_index if state.resolved_display_index is not None else state.settings.display_index,
             "last_update": metrics.last_update,
             "errors": [metrics.last_error] if metrics.last_error else [],
             "wled_online": h.online,

server/src/wled_controller/main.py

@@ -16,6 +16,8 @@ from wled_controller.config import get_config
 from wled_controller.core.processor_manager import ProcessorManager
 from wled_controller.storage import DeviceStore
 from wled_controller.storage.template_store import TemplateStore
+from wled_controller.storage.postprocessing_template_store import PostprocessingTemplateStore
+from wled_controller.storage.picture_stream_store import PictureStreamStore
 from wled_controller.utils import setup_logging, get_logger
 
 # Initialize logging
@@ -28,7 +30,65 @@ config = get_config()
 # Initialize storage and processing
 device_store = DeviceStore(config.storage.devices_file)
 template_store = TemplateStore(config.storage.templates_file)
-processor_manager = ProcessorManager()
+pp_template_store = PostprocessingTemplateStore(config.storage.postprocessing_templates_file)
+picture_stream_store = PictureStreamStore(config.storage.picture_streams_file)
+
+# Assign first available template to devices with missing/invalid template
+all_templates = template_store.get_all_templates()
+if all_templates:
+    valid_ids = {t.id for t in all_templates}
+    for device in device_store.get_all_devices():
+        if not device.capture_template_id or device.capture_template_id not in valid_ids:
+            old_id = device.capture_template_id
+            device_store.update_device(device.id, capture_template_id=all_templates[0].id)
+            logger.info(
+                f"Assigned template '{all_templates[0].name}' to device '{device.name}' "
+                f"(was '{old_id}')"
+            )
+
+# Migrate devices without picture_stream_id: create streams from legacy settings
+for device in device_store.get_all_devices():
+    if not device.picture_stream_id:
+        try:
+            # Create a raw stream from the device's current capture settings
+            raw_stream = picture_stream_store.create_stream(
+                name=f"{device.name} - Raw",
+                stream_type="raw",
+                display_index=device.settings.display_index,
+                capture_template_id=device.capture_template_id,
+                target_fps=device.settings.fps,
+                description=f"Auto-migrated from device '{device.name}'",
+            )
+
+            # Create a processed stream with the first PP template
+            pp_templates = pp_template_store.get_all_templates()
+            if pp_templates:
+                processed_stream = picture_stream_store.create_stream(
+                    name=f"{device.name} - Processed",
+                    stream_type="processed",
+                    source_stream_id=raw_stream.id,
+                    postprocessing_template_id=pp_templates[0].id,
+                    description=f"Auto-migrated from device '{device.name}'",
+                )
+                device_store.update_device(device.id, picture_stream_id=processed_stream.id)
+                logger.info(
+                    f"Migrated device '{device.name}': created raw stream '{raw_stream.id}' "
+                    f"+ processed stream '{processed_stream.id}'"
+                )
+            else:
+                # No PP templates, assign raw stream directly
+                device_store.update_device(device.id, picture_stream_id=raw_stream.id)
+                logger.info(
+                    f"Migrated device '{device.name}': created raw stream '{raw_stream.id}'"
+                )
+        except Exception as e:
+            logger.error(f"Failed to migrate device '{device.name}': {e}")
+
+processor_manager = ProcessorManager(
+    picture_stream_store=picture_stream_store,
+    capture_template_store=template_store,
+    pp_template_store=pp_template_store,
+)
 
 
 @asynccontextmanager
@@ -61,7 +121,11 @@ async def lifespan(app: FastAPI):
     logger.info("All API requests require valid Bearer token authentication")
 
     # Initialize API dependencies
-    init_dependencies(device_store, template_store, processor_manager)
+    init_dependencies(
+        device_store, template_store, processor_manager,
+        pp_template_store=pp_template_store,
+        picture_stream_store=picture_stream_store,
+    )
 
     # Load existing devices into processor manager
     devices = device_store.get_all_devices()
@@ -74,6 +138,7 @@ async def lifespan(app: FastAPI):
                 settings=device.settings,
                 calibration=device.calibration,
                 capture_template_id=device.capture_template_id,
+                picture_stream_id=device.picture_stream_id,
             )
             logger.info(f"Loaded device: {device.name} ({device.id})")
         except Exception as e:

server/src/wled_controller/static/app.js

@@ -347,6 +347,12 @@ function switchTab(name) {
     if (name === 'templates') {
         loadCaptureTemplates();
     }
+    if (name === 'streams') {
+        loadPictureStreams();
+    }
+    if (name === 'pp-templates') {
+        loadPPTemplates();
+    }
 }
 
 function initTabs() {
@@ -625,8 +631,8 @@ function createDeviceCard(device) {
                 <button class="btn btn-icon btn-secondary" onclick="showSettings('${device.id}')" title="${t('device.button.settings')}">
                     ⚙️
                 </button>
-                <button class="btn btn-icon btn-secondary" onclick="showCaptureSettings('${device.id}')" title="${t('device.button.capture_settings')}">
-                    🎬
+                <button class="btn btn-icon btn-secondary" onclick="showStreamSelector('${device.id}')" title="${t('device.button.stream_selector')}">
+                    📺
                 </button>
                 <button class="btn btn-icon btn-secondary" onclick="showCalibration('${device.id}')" title="${t('device.button.calibrate')}">
                     📐
@@ -930,20 +936,14 @@ async function showCaptureSettings(deviceId) {
                 templateSelect.appendChild(opt);
             });
         }
-        if (templateSelect.options.length === 0) {
-            const opt = document.createElement('option');
-            opt.value = 'tpl_mss_default';
-            opt.textContent = 'MSS (Default)';
-            templateSelect.appendChild(opt);
-        }
-        templateSelect.value = device.capture_template_id || 'tpl_mss_default';
+        templateSelect.value = device.capture_template_id || '';
 
         // Store device ID, current settings snapshot, and initial values for dirty check
         document.getElementById('capture-settings-device-id').value = device.id;
         captureSettingsInitialValues = {
             display_index: String(device.settings.display_index ?? 0),
             fps: String(currentSettings.fps ?? 30),
-            capture_template_id: device.capture_template_id || 'tpl_mss_default',
+            capture_template_id: device.capture_template_id || '',
             _currentSettings: currentSettings,
         };
 
@@ -2359,25 +2359,16 @@ function renderTemplatesList(templates) {
         return;
     }
 
-    const defaultTemplates = templates.filter(t => t.is_default);
-    const customTemplates = templates.filter(t => !t.is_default);
-
     const renderCard = (template) => {
         const engineIcon = getEngineIcon(template.engine_type);
-        const defaultBadge = template.is_default
-            ? `<span class="badge badge-default">${t('templates.default')}</span>`
-            : '';
 
         return `
             <div class="template-card" data-template-id="${template.id}">
-                ${!template.is_default ? `
-                    <button class="card-remove-btn" onclick="deleteTemplate('${template.id}')" title="${t('common.delete')}">&#x2715;</button>
-                ` : ''}
+                <button class="card-remove-btn" onclick="deleteTemplate('${template.id}')" title="${t('common.delete')}">&#x2715;</button>
                 <div class="template-card-header">
                     <div class="template-name">
                         ${engineIcon} ${escapeHtml(template.name)}
                     </div>
-                    ${defaultBadge}
                 </div>
                 <div class="template-config">
                     <strong>${t('templates.engine')}</strong> ${template.engine_type.toUpperCase()}
@@ -2401,22 +2392,15 @@ function renderTemplatesList(templates) {
                     <button class="btn btn-icon btn-secondary" onclick="showTestTemplateModal('${template.id}')" title="${t('templates.test.title')}">
                         🧪
                     </button>
-                    ${!template.is_default ? `
-                        <button class="btn btn-icon btn-secondary" onclick="editTemplate('${template.id}')" title="${t('common.edit')}">
-                            ✏️
-                        </button>
-                    ` : ''}
+                    <button class="btn btn-icon btn-secondary" onclick="editTemplate('${template.id}')" title="${t('common.edit')}">
+                        ✏️
+                    </button>
                 </div>
             </div>
         `;
     };
 
-    let html = defaultTemplates.map(renderCard).join('');
-
-    if (customTemplates.length > 0) {
-        html += `<div class="templates-separator"><span>${t('templates.custom')}</span></div>`;
-        html += customTemplates.map(renderCard).join('');
-    }
+    let html = templates.map(renderCard).join('');
 
     html += `<div class="template-card add-template-card" onclick="showAddTemplateModal()">
         <div class="add-template-icon">+</div>
@@ -2978,3 +2962,773 @@ async function deleteTemplate(templateId) {
         showToast(t('templates.error.delete') + ': ' + error.message, 'error');
     }
 }
+
+// ===== Picture Streams =====
+
+let _cachedStreams = [];
+let _cachedPPTemplates = [];
+
+async function loadPictureStreams() {
+    try {
+        const response = await fetchWithAuth('/picture-streams');
+        if (!response.ok) {
+            throw new Error(`Failed to load streams: ${response.status}`);
+        }
+        const data = await response.json();
+        _cachedStreams = data.streams || [];
+        renderPictureStreamsList(_cachedStreams);
+    } catch (error) {
+        console.error('Error loading picture streams:', error);
+        document.getElementById('streams-list').innerHTML = `
+            <div class="error-message">${t('streams.error.load')}: ${error.message}</div>
+        `;
+    }
+}
+
+function renderPictureStreamsList(streams) {
+    const container = document.getElementById('streams-list');
+
+    if (streams.length === 0) {
+        container.innerHTML = `<div class="template-card add-template-card" onclick="showAddStreamModal()">
+            <div class="add-template-icon">+</div>
+            <div class="add-template-label">${t('streams.add')}</div>
+        </div>`;
+        return;
+    }
+
+    const renderCard = (stream) => {
+        const typeIcon = stream.stream_type === 'raw' ? '📷' : '🎨';
+        const typeBadge = stream.stream_type === 'raw'
+            ? `<span class="badge badge-raw">${t('streams.type.raw')}</span>`
+            : `<span class="badge badge-processed">${t('streams.type.processed')}</span>`;
+
+        let detailsHtml = '';
+        if (stream.stream_type === 'raw') {
+            detailsHtml = `
+                <div class="template-config">
+                    <strong>${t('streams.display')}</strong> ${stream.display_index ?? 0}
+                </div>
+                <div class="template-config">
+                    <strong>${t('streams.target_fps')}</strong> ${stream.target_fps ?? 30}
+                </div>
+            `;
+        } else {
+            // Find source stream name and PP template name
+            const sourceStream = _cachedStreams.find(s => s.id === stream.source_stream_id);
+            const sourceName = sourceStream ? escapeHtml(sourceStream.name) : (stream.source_stream_id || '-');
+            detailsHtml = `
+                <div class="template-config">
+                    <strong>${t('streams.source')}</strong> ${sourceName}
+                </div>
+            `;
+        }
+
+        return `
+            <div class="template-card" data-stream-id="${stream.id}">
+                <button class="card-remove-btn" onclick="deleteStream('${stream.id}')" title="${t('common.delete')}">&#x2715;</button>
+                <div class="template-card-header">
+                    <div class="template-name">
+                        ${typeIcon} ${escapeHtml(stream.name)}
+                    </div>
+                    ${typeBadge}
+                </div>
+                ${detailsHtml}
+                ${stream.description ? `<div class="template-config" style="opacity:0.7;">${escapeHtml(stream.description)}</div>` : ''}
+                <div class="template-card-actions">
+                    <button class="btn btn-icon btn-secondary" onclick="showTestStreamModal('${stream.id}')" title="${t('streams.test.title')}">
+                        🧪
+                    </button>
+                    <button class="btn btn-icon btn-secondary" onclick="editStream('${stream.id}')" title="${t('common.edit')}">
+                        ✏️
+                    </button>
+                </div>
+            </div>
+        `;
+    };
+
+    let html = streams.map(renderCard).join('');
+    html += `<div class="template-card add-template-card" onclick="showAddStreamModal()">
+        <div class="add-template-icon">+</div>
+        <div class="add-template-label">${t('streams.add')}</div>
+    </div>`;
+
+    container.innerHTML = html;
+}
+
+function onStreamTypeChange() {
+    const streamType = document.getElementById('stream-type').value;
+    document.getElementById('stream-raw-fields').style.display = streamType === 'raw' ? '' : 'none';
+    document.getElementById('stream-processed-fields').style.display = streamType === 'processed' ? '' : 'none';
+}
+
+async function showAddStreamModal() {
+    document.getElementById('stream-modal-title').textContent = t('streams.add');
+    document.getElementById('stream-form').reset();
+    document.getElementById('stream-id').value = '';
+    document.getElementById('stream-error').style.display = 'none';
+    document.getElementById('stream-type').disabled = false;
+
+    // Reset to raw type
+    document.getElementById('stream-type').value = 'raw';
+    onStreamTypeChange();
+
+    // Populate dropdowns
+    await populateStreamModalDropdowns();
+
+    const modal = document.getElementById('stream-modal');
+    modal.style.display = 'flex';
+    lockBody();
+    modal.onclick = (e) => { if (e.target === modal) closeStreamModal(); };
+}
+
+async function editStream(streamId) {
+    try {
+        const response = await fetchWithAuth(`/picture-streams/${streamId}`);
+        if (!response.ok) throw new Error(`Failed to load stream: ${response.status}`);
+        const stream = await response.json();
+
+        document.getElementById('stream-modal-title').textContent = t('streams.edit');
+        document.getElementById('stream-id').value = streamId;
+        document.getElementById('stream-name').value = stream.name;
+        document.getElementById('stream-description').value = stream.description || '';
+        document.getElementById('stream-error').style.display = 'none';
+
+        // Set type and disable changing it for existing streams
+        document.getElementById('stream-type').value = stream.stream_type;
+        document.getElementById('stream-type').disabled = true;
+        onStreamTypeChange();
+
+        // Populate dropdowns before setting values
+        await populateStreamModalDropdowns();
+
+        if (stream.stream_type === 'raw') {
+            document.getElementById('stream-display-index').value = String(stream.display_index ?? 0);
+            document.getElementById('stream-capture-template').value = stream.capture_template_id || '';
+            const fps = stream.target_fps ?? 30;
+            document.getElementById('stream-target-fps').value = fps;
+            document.getElementById('stream-target-fps-value').textContent = fps;
+        } else {
+            document.getElementById('stream-source').value = stream.source_stream_id || '';
+            document.getElementById('stream-pp-template').value = stream.postprocessing_template_id || '';
+        }
+
+        const modal = document.getElementById('stream-modal');
+        modal.style.display = 'flex';
+        lockBody();
+        modal.onclick = (e) => { if (e.target === modal) closeStreamModal(); };
+    } catch (error) {
+        console.error('Error loading stream:', error);
+        showToast(t('streams.error.load') + ': ' + error.message, 'error');
+    }
+}
+
+async function populateStreamModalDropdowns() {
+    // Load displays, capture templates, streams, and PP templates in parallel
+    const [displaysRes, captureTemplatesRes, streamsRes, ppTemplatesRes] = await Promise.all([
+        fetch(`${API_BASE}/config/displays`, { headers: getHeaders() }),
+        fetchWithAuth('/capture-templates'),
+        fetchWithAuth('/picture-streams'),
+        fetchWithAuth('/postprocessing-templates'),
+    ]);
+
+    // Displays
+    const displaySelect = document.getElementById('stream-display-index');
+    displaySelect.innerHTML = '';
+    if (displaysRes.ok) {
+        const displaysData = await displaysRes.json();
+        (displaysData.displays || []).forEach(d => {
+            const opt = document.createElement('option');
+            opt.value = d.index;
+            opt.textContent = `${d.index}: ${d.width}x${d.height}${d.is_primary ? ` (${t('displays.badge.primary')})` : ''}`;
+            displaySelect.appendChild(opt);
+        });
+    }
+    if (displaySelect.options.length === 0) {
+        const opt = document.createElement('option');
+        opt.value = '0';
+        opt.textContent = '0';
+        displaySelect.appendChild(opt);
+    }
+
+    // Capture templates
+    const templateSelect = document.getElementById('stream-capture-template');
+    templateSelect.innerHTML = '';
+    if (captureTemplatesRes.ok) {
+        const data = await captureTemplatesRes.json();
+        (data.templates || []).forEach(tmpl => {
+            const opt = document.createElement('option');
+            opt.value = tmpl.id;
+            opt.textContent = `${getEngineIcon(tmpl.engine_type)} ${tmpl.name}`;
+            templateSelect.appendChild(opt);
+        });
+    }
+
+    // Source streams (all existing streams)
+    const sourceSelect = document.getElementById('stream-source');
+    sourceSelect.innerHTML = '';
+    if (streamsRes.ok) {
+        const data = await streamsRes.json();
+        const editingId = document.getElementById('stream-id').value;
+        (data.streams || []).forEach(s => {
+            // Don't show the current stream as a possible source
+            if (s.id === editingId) return;
+            const opt = document.createElement('option');
+            opt.value = s.id;
+            const typeLabel = s.stream_type === 'raw' ? '📷' : '🎨';
+            opt.textContent = `${typeLabel} ${s.name}`;
+            sourceSelect.appendChild(opt);
+        });
+    }
+
+    // PP templates
+    const ppSelect = document.getElementById('stream-pp-template');
+    ppSelect.innerHTML = '';
+    if (ppTemplatesRes.ok) {
+        const data = await ppTemplatesRes.json();
+        (data.templates || []).forEach(tmpl => {
+            const opt = document.createElement('option');
+            opt.value = tmpl.id;
+            opt.textContent = tmpl.name;
+            ppSelect.appendChild(opt);
+        });
+    }
+}
+
+async function saveStream() {
+    const streamId = document.getElementById('stream-id').value;
+    const name = document.getElementById('stream-name').value.trim();
+    const streamType = document.getElementById('stream-type').value;
+    const description = document.getElementById('stream-description').value.trim();
+    const errorEl = document.getElementById('stream-error');
+
+    if (!name) {
+        showToast(t('streams.error.required'), 'error');
+        return;
+    }
+
+    const payload = { name, description: description || null };
+
+    if (!streamId) {
+        // Creating - include stream_type
+        payload.stream_type = streamType;
+    }
+
+    if (streamType === 'raw') {
+        payload.display_index = parseInt(document.getElementById('stream-display-index').value) || 0;
+        payload.capture_template_id = document.getElementById('stream-capture-template').value;
+        payload.target_fps = parseInt(document.getElementById('stream-target-fps').value) || 30;
+    } else {
+        payload.source_stream_id = document.getElementById('stream-source').value;
+        payload.postprocessing_template_id = document.getElementById('stream-pp-template').value;
+    }
+
+    try {
+        let response;
+        if (streamId) {
+            response = await fetchWithAuth(`/picture-streams/${streamId}`, {
+                method: 'PUT',
+                body: JSON.stringify(payload)
+            });
+        } else {
+            response = await fetchWithAuth('/picture-streams', {
+                method: 'POST',
+                body: JSON.stringify(payload)
+            });
+        }
+
+        if (!response.ok) {
+            const error = await response.json();
+            throw new Error(error.detail || error.message || 'Failed to save stream');
+        }
+
+        showToast(streamId ? t('streams.updated') : t('streams.created'), 'success');
+        closeStreamModal();
+        await loadPictureStreams();
+    } catch (error) {
+        console.error('Error saving stream:', error);
+        errorEl.textContent = error.message;
+        errorEl.style.display = 'block';
+    }
+}
+
+async function deleteStream(streamId) {
+    const confirmed = await showConfirm(t('streams.delete.confirm'));
+    if (!confirmed) return;
+
+    try {
+        const response = await fetchWithAuth(`/picture-streams/${streamId}`, {
+            method: 'DELETE'
+        });
+
+        if (!response.ok) {
+            const error = await response.json();
+            throw new Error(error.detail || error.message || 'Failed to delete stream');
+        }
+
+        showToast(t('streams.deleted'), 'success');
+        await loadPictureStreams();
+    } catch (error) {
+        console.error('Error deleting stream:', error);
+        showToast(t('streams.error.delete') + ': ' + error.message, 'error');
+    }
+}
+
+function closeStreamModal() {
+    document.getElementById('stream-modal').style.display = 'none';
+    document.getElementById('stream-type').disabled = false;
+    unlockBody();
+}
+
+// ===== Picture Stream Test =====
+
+let _currentTestStreamId = null;
+
+async function showTestStreamModal(streamId) {
+    _currentTestStreamId = streamId;
+    restoreStreamTestDuration();
+    document.getElementById('test-stream-results').style.display = 'none';
+
+    const modal = document.getElementById('test-stream-modal');
+    modal.style.display = 'flex';
+    lockBody();
+    modal.onclick = (e) => { if (e.target === modal) closeTestStreamModal(); };
+}
+
+function closeTestStreamModal() {
+    document.getElementById('test-stream-modal').style.display = 'none';
+    unlockBody();
+    _currentTestStreamId = null;
+}
+
+function updateStreamTestDuration(value) {
+    document.getElementById('test-stream-duration-value').textContent = value;
+    localStorage.setItem('lastStreamTestDuration', value);
+}
+
+function restoreStreamTestDuration() {
+    const saved = localStorage.getItem('lastStreamTestDuration') || '5';
+    document.getElementById('test-stream-duration').value = saved;
+    document.getElementById('test-stream-duration-value').textContent = saved;
+}
+
+async function runStreamTest() {
+    if (!_currentTestStreamId) return;
+
+    const captureDuration = parseFloat(document.getElementById('test-stream-duration').value);
+
+    showOverlaySpinner(t('streams.test.running'), captureDuration);
+
+    try {
+        const response = await fetchWithAuth(`/picture-streams/${_currentTestStreamId}/test`, {
+            method: 'POST',
+            body: JSON.stringify({ capture_duration: captureDuration })
+        });
+
+        if (!response.ok) {
+            const error = await response.json();
+            throw new Error(error.detail || error.message || 'Test failed');
+        }
+
+        const result = await response.json();
+        displayStreamTestResults(result);
+    } catch (error) {
+        console.error('Error running stream test:', error);
+        hideOverlaySpinner();
+        showToast(t('streams.test.error.failed') + ': ' + error.message, 'error');
+    }
+}
+
+function displayStreamTestResults(result) {
+    hideOverlaySpinner();
+
+    const previewImg = document.getElementById('test-stream-preview-image');
+    previewImg.innerHTML = `<img src="${result.full_capture.image}" alt="Stream preview" style="max-width: 100%; border-radius: 4px;">`;
+
+    document.getElementById('test-stream-actual-duration').textContent = `${result.performance.capture_duration_s.toFixed(2)}s`;
+    document.getElementById('test-stream-frame-count').textContent = result.performance.frame_count;
+    document.getElementById('test-stream-actual-fps').textContent = `${result.performance.actual_fps.toFixed(1)} FPS`;
+    document.getElementById('test-stream-avg-capture-time').textContent = `${result.performance.avg_capture_time_ms.toFixed(1)}ms`;
+
+    document.getElementById('test-stream-results').style.display = 'block';
+}
+
+// ===== Processing Templates =====
+
+async function loadPPTemplates() {
+    try {
+        const response = await fetchWithAuth('/postprocessing-templates');
+        if (!response.ok) {
+            throw new Error(`Failed to load templates: ${response.status}`);
+        }
+        const data = await response.json();
+        _cachedPPTemplates = data.templates || [];
+        renderPPTemplatesList(_cachedPPTemplates);
+    } catch (error) {
+        console.error('Error loading PP templates:', error);
+        document.getElementById('pp-templates-list').innerHTML = `
+            <div class="error-message">${t('postprocessing.error.load')}: ${error.message}</div>
+        `;
+    }
+}
+
+function renderPPTemplatesList(templates) {
+    const container = document.getElementById('pp-templates-list');
+
+    if (templates.length === 0) {
+        container.innerHTML = `<div class="template-card add-template-card" onclick="showAddPPTemplateModal()">
+            <div class="add-template-icon">+</div>
+            <div class="add-template-label">${t('postprocessing.add')}</div>
+        </div>`;
+        return;
+    }
+
+    const renderCard = (tmpl) => {
+        const configEntries = {
+            [t('postprocessing.gamma')]: tmpl.gamma,
+            [t('postprocessing.saturation')]: tmpl.saturation,
+            [t('postprocessing.brightness')]: tmpl.brightness,
+            [t('postprocessing.smoothing')]: tmpl.smoothing,
+        };
+
+        return `
+            <div class="template-card" data-pp-template-id="${tmpl.id}">
+                <button class="card-remove-btn" onclick="deletePPTemplate('${tmpl.id}')" title="${t('common.delete')}">&#x2715;</button>
+                <div class="template-card-header">
+                    <div class="template-name">
+                        🎨 ${escapeHtml(tmpl.name)}
+                    </div>
+                </div>
+                ${tmpl.description ? `<div class="template-config" style="opacity:0.7;">${escapeHtml(tmpl.description)}</div>` : ''}
+                <details class="template-config-details">
+                    <summary>${t('postprocessing.config.show')}</summary>
+                    <table class="config-table">
+                        ${Object.entries(configEntries).map(([key, val]) => `
+                            <tr>
+                                <td class="config-key">${escapeHtml(key)}</td>
+                                <td class="config-value">${escapeHtml(String(val))}</td>
+                            </tr>
+                        `).join('')}
+                    </table>
+                </details>
+                <div class="template-card-actions">
+                    <button class="btn btn-icon btn-secondary" onclick="editPPTemplate('${tmpl.id}')" title="${t('common.edit')}">
+                        ✏️
+                    </button>
+                </div>
+            </div>
+        `;
+    };
+
+    let html = templates.map(renderCard).join('');
+    html += `<div class="template-card add-template-card" onclick="showAddPPTemplateModal()">
+        <div class="add-template-icon">+</div>
+        <div class="add-template-label">${t('postprocessing.add')}</div>
+    </div>`;
+
+    container.innerHTML = html;
+}
+
+async function showAddPPTemplateModal() {
+    document.getElementById('pp-template-modal-title').textContent = t('postprocessing.add');
+    document.getElementById('pp-template-form').reset();
+    document.getElementById('pp-template-id').value = '';
+    document.getElementById('pp-template-error').style.display = 'none';
+
+    // Reset slider displays to defaults
+    document.getElementById('pp-template-gamma').value = '2.2';
+    document.getElementById('pp-template-gamma-value').textContent = '2.2';
+    document.getElementById('pp-template-saturation').value = '1.0';
+    document.getElementById('pp-template-saturation-value').textContent = '1.0';
+    document.getElementById('pp-template-brightness').value = '1.0';
+    document.getElementById('pp-template-brightness-value').textContent = '1.0';
+    document.getElementById('pp-template-smoothing').value = '0.3';
+    document.getElementById('pp-template-smoothing-value').textContent = '0.3';
+
+    const modal = document.getElementById('pp-template-modal');
+    modal.style.display = 'flex';
+    lockBody();
+    modal.onclick = (e) => { if (e.target === modal) closePPTemplateModal(); };
+}
+
+async function editPPTemplate(templateId) {
+    try {
+        const response = await fetchWithAuth(`/postprocessing-templates/${templateId}`);
+        if (!response.ok) throw new Error(`Failed to load template: ${response.status}`);
+        const tmpl = await response.json();
+
+        document.getElementById('pp-template-modal-title').textContent = t('postprocessing.edit');
+        document.getElementById('pp-template-id').value = templateId;
+        document.getElementById('pp-template-name').value = tmpl.name;
+        document.getElementById('pp-template-description').value = tmpl.description || '';
+        document.getElementById('pp-template-error').style.display = 'none';
+
+        // Set sliders
+        document.getElementById('pp-template-gamma').value = tmpl.gamma;
+        document.getElementById('pp-template-gamma-value').textContent = tmpl.gamma;
+        document.getElementById('pp-template-saturation').value = tmpl.saturation;
+        document.getElementById('pp-template-saturation-value').textContent = tmpl.saturation;
+        document.getElementById('pp-template-brightness').value = tmpl.brightness;
+        document.getElementById('pp-template-brightness-value').textContent = tmpl.brightness;
+        document.getElementById('pp-template-smoothing').value = tmpl.smoothing;
+        document.getElementById('pp-template-smoothing-value').textContent = tmpl.smoothing;
+
+        const modal = document.getElementById('pp-template-modal');
+        modal.style.display = 'flex';
+        lockBody();
+        modal.onclick = (e) => { if (e.target === modal) closePPTemplateModal(); };
+    } catch (error) {
+        console.error('Error loading PP template:', error);
+        showToast(t('postprocessing.error.load') + ': ' + error.message, 'error');
+    }
+}
+
+async function savePPTemplate() {
+    const templateId = document.getElementById('pp-template-id').value;
+    const name = document.getElementById('pp-template-name').value.trim();
+    const description = document.getElementById('pp-template-description').value.trim();
+    const errorEl = document.getElementById('pp-template-error');
+
+    if (!name) {
+        showToast(t('postprocessing.error.required'), 'error');
+        return;
+    }
+
+    const payload = {
+        name,
+        gamma: parseFloat(document.getElementById('pp-template-gamma').value),
+        saturation: parseFloat(document.getElementById('pp-template-saturation').value),
+        brightness: parseFloat(document.getElementById('pp-template-brightness').value),
+        smoothing: parseFloat(document.getElementById('pp-template-smoothing').value),
+        description: description || null,
+    };
+
+    try {
+        let response;
+        if (templateId) {
+            response = await fetchWithAuth(`/postprocessing-templates/${templateId}`, {
+                method: 'PUT',
+                body: JSON.stringify(payload)
+            });
+        } else {
+            response = await fetchWithAuth('/postprocessing-templates', {
+                method: 'POST',
+                body: JSON.stringify(payload)
+            });
+        }
+
+        if (!response.ok) {
+            const error = await response.json();
+            throw new Error(error.detail || error.message || 'Failed to save template');
+        }
+
+        showToast(templateId ? t('postprocessing.updated') : t('postprocessing.created'), 'success');
+        closePPTemplateModal();
+        await loadPPTemplates();
+    } catch (error) {
+        console.error('Error saving PP template:', error);
+        errorEl.textContent = error.message;
+        errorEl.style.display = 'block';
+    }
+}
+
+async function deletePPTemplate(templateId) {
+    const confirmed = await showConfirm(t('postprocessing.delete.confirm'));
+    if (!confirmed) return;
+
+    try {
+        const response = await fetchWithAuth(`/postprocessing-templates/${templateId}`, {
+            method: 'DELETE'
+        });
+
+        if (!response.ok) {
+            const error = await response.json();
+            throw new Error(error.detail || error.message || 'Failed to delete template');
+        }
+
+        showToast(t('postprocessing.deleted'), 'success');
+        await loadPPTemplates();
+    } catch (error) {
+        console.error('Error deleting PP template:', error);
+        showToast(t('postprocessing.error.delete') + ': ' + error.message, 'error');
+    }
+}
+
+function closePPTemplateModal() {
+    document.getElementById('pp-template-modal').style.display = 'none';
+    unlockBody();
+}
+
+// ===== Device Stream Selector =====
+
+let streamSelectorInitialValues = {};
+
+async function showStreamSelector(deviceId) {
+    try {
+        const [deviceResponse, streamsResponse, settingsResponse] = await Promise.all([
+            fetch(`${API_BASE}/devices/${deviceId}`, { headers: getHeaders() }),
+            fetchWithAuth('/picture-streams'),
+            fetch(`${API_BASE}/devices/${deviceId}/settings`, { headers: getHeaders() }),
+        ]);
+
+        if (deviceResponse.status === 401) {
+            handle401Error();
+            return;
+        }
+
+        if (!deviceResponse.ok) {
+            showToast('Failed to load device', 'error');
+            return;
+        }
+
+        const device = await deviceResponse.json();
+        const settings = settingsResponse.ok ? await settingsResponse.json() : {};
+
+        // Populate stream select
+        const streamSelect = document.getElementById('stream-selector-stream');
+        streamSelect.innerHTML = '';
+
+        if (streamsResponse.ok) {
+            const data = await streamsResponse.json();
+            (data.streams || []).forEach(s => {
+                const opt = document.createElement('option');
+                opt.value = s.id;
+                const typeIcon = s.stream_type === 'raw' ? '📷' : '🎨';
+                opt.textContent = `${typeIcon} ${s.name}`;
+                streamSelect.appendChild(opt);
+            });
+        }
+
+        const currentStreamId = device.picture_stream_id || '';
+        streamSelect.value = currentStreamId;
+
+        // Populate LED projection fields
+        const borderWidth = settings.border_width ?? device.settings?.border_width ?? 10;
+        document.getElementById('stream-selector-border-width').value = borderWidth;
+        document.getElementById('stream-selector-interpolation').value = device.settings?.interpolation_mode || 'average';
+
+        streamSelectorInitialValues = {
+            stream: currentStreamId,
+            border_width: String(borderWidth),
+            interpolation: device.settings?.interpolation_mode || 'average',
+        };
+
+        document.getElementById('stream-selector-device-id').value = deviceId;
+        document.getElementById('stream-selector-error').style.display = 'none';
+
+        // Show info about selected stream
+        updateStreamSelectorInfo(streamSelect.value);
+        streamSelect.onchange = () => updateStreamSelectorInfo(streamSelect.value);
+
+        const modal = document.getElementById('stream-selector-modal');
+        modal.style.display = 'flex';
+        lockBody();
+        modal.onclick = (e) => { if (e.target === modal) closeStreamSelectorModal(); };
+    } catch (error) {
+        console.error('Failed to load stream settings:', error);
+        showToast('Failed to load stream settings', 'error');
+    }
+}
+
+async function updateStreamSelectorInfo(streamId) {
+    const infoPanel = document.getElementById('stream-selector-info');
+    if (!streamId) {
+        infoPanel.style.display = 'none';
+        return;
+    }
+
+    try {
+        const response = await fetchWithAuth(`/picture-streams/${streamId}`);
+        if (!response.ok) {
+            infoPanel.style.display = 'none';
+            return;
+        }
+        const stream = await response.json();
+
+        let infoHtml = `<div class="stream-info-type"><strong>${t('streams.type')}</strong> ${stream.stream_type === 'raw' ? t('streams.type.raw') : t('streams.type.processed')}</div>`;
+
+        if (stream.stream_type === 'raw') {
+            infoHtml += `<div><strong>${t('streams.display')}</strong> ${stream.display_index ?? 0}</div>`;
+            infoHtml += `<div><strong>${t('streams.target_fps')}</strong> ${stream.target_fps ?? 30}</div>`;
+        } else {
+            const sourceStream = _cachedStreams.find(s => s.id === stream.source_stream_id);
+            infoHtml += `<div><strong>${t('streams.source')}</strong> ${sourceStream ? escapeHtml(sourceStream.name) : stream.source_stream_id}</div>`;
+        }
+
+        infoPanel.innerHTML = infoHtml;
+        infoPanel.style.display = '';
+    } catch {
+        infoPanel.style.display = 'none';
+    }
+}
+
+async function saveStreamSelector() {
+    const deviceId = document.getElementById('stream-selector-device-id').value;
+    const pictureStreamId = document.getElementById('stream-selector-stream').value;
+    const borderWidth = parseInt(document.getElementById('stream-selector-border-width').value) || 10;
+    const interpolation = document.getElementById('stream-selector-interpolation').value;
+    const errorEl = document.getElementById('stream-selector-error');
+
+    try {
+        // Save picture stream assignment
+        const response = await fetch(`${API_BASE}/devices/${deviceId}`, {
+            method: 'PUT',
+            headers: getHeaders(),
+            body: JSON.stringify({ picture_stream_id: pictureStreamId })
+        });
+
+        if (response.status === 401) {
+            handle401Error();
+            return;
+        }
+
+        if (!response.ok) {
+            const error = await response.json();
+            throw new Error(error.detail || error.message || 'Failed to save');
+        }
+
+        // Save LED projection settings — merge with existing to avoid overwriting other fields
+        const currentSettingsRes = await fetch(`${API_BASE}/devices/${deviceId}/settings`, { headers: getHeaders() });
+        const currentSettings = currentSettingsRes.ok ? await currentSettingsRes.json() : {};
+        const settingsResponse = await fetch(`${API_BASE}/devices/${deviceId}/settings`, {
+            method: 'PUT',
+            headers: getHeaders(),
+            body: JSON.stringify({ ...currentSettings, border_width: borderWidth, interpolation_mode: interpolation })
+        });
+
+        if (!settingsResponse.ok) {
+            const error = await settingsResponse.json();
+            throw new Error(error.detail || error.message || 'Failed to save settings');
+        }
+
+        showToast(t('device.stream_selector.saved'), 'success');
+        forceCloseStreamSelectorModal();
+        await loadDevices();
+    } catch (error) {
+        console.error('Error saving stream settings:', error);
+        errorEl.textContent = error.message;
+        errorEl.style.display = 'block';
+    }
+}
+
+function isStreamSettingsDirty() {
+    return (
+        document.getElementById('stream-selector-stream').value !== streamSelectorInitialValues.stream ||
+        document.getElementById('stream-selector-border-width').value !== streamSelectorInitialValues.border_width ||
+        document.getElementById('stream-selector-interpolation').value !== streamSelectorInitialValues.interpolation
+    );
+}
+
+async function closeStreamSelectorModal() {
+    if (isStreamSettingsDirty()) {
+        const confirmed = await showConfirm(t('modal.discard_changes'));
+        if (!confirmed) return;
+    }
+    forceCloseStreamSelectorModal();
+}
+
+function forceCloseStreamSelectorModal() {
+    document.getElementById('stream-selector-modal').style.display = 'none';
+    document.getElementById('stream-selector-error').style.display = 'none';
+    unlockBody();
+    streamSelectorInitialValues = {};
+}

server/src/wled_controller/static/index.html

@@ -36,7 +36,9 @@
             <div class="tab-bar">
                 <button class="tab-btn active" data-tab="devices" onclick="switchTab('devices')"><span data-i18n="devices.title">💡 Devices</span></button>
                 <button class="tab-btn" data-tab="displays" onclick="switchTab('displays')"><span data-i18n="displays.layout">🖥️ Displays</span></button>
+                <button class="tab-btn" data-tab="streams" onclick="switchTab('streams')"><span data-i18n="streams.title">📺 Picture Streams</span></button>
                 <button class="tab-btn" data-tab="templates" onclick="switchTab('templates')"><span data-i18n="templates.title">🎯 Capture Templates</span></button>
+                <button class="tab-btn" data-tab="pp-templates" onclick="switchTab('pp-templates')"><span data-i18n="postprocessing.title">🎨 Processing Templates</span></button>
             </div>
 
             <div class="tab-panel active" id="tab-devices">
@@ -49,19 +51,30 @@
                     <span data-i18n="devices.wled_note2">This controller sends pixel color data and controls brightness per device.</span>
                 </p>
                 <div id="devices-list" class="devices-grid">
-                    <div class="loading" data-i18n="devices.loading">Loading devices...</div>
+                    <div class="loading-spinner"></div>
                 </div>
             </div>
 
             <div class="tab-panel" id="tab-displays">
                 <div class="display-layout-preview">
                     <div id="display-layout-canvas" class="display-layout-canvas">
-                        <div class="loading" data-i18n="displays.loading">Loading layout...</div>
+                        <div class="loading-spinner"></div>
                     </div>
                 </div>
                 <div id="displays-list" style="display: none;"></div>
             </div>
 
+            <div class="tab-panel" id="tab-streams">
+                <p class="section-tip">
+                    <span data-i18n="streams.description">
+                        Picture streams define the capture pipeline. A raw stream captures from a display using a capture template. A processed stream applies postprocessing to another stream. Assign streams to devices.
+                    </span>
+                </p>
+                <div id="streams-list" class="templates-grid">
+                    <div class="loading-spinner"></div>
+                </div>
+            </div>
+
             <div class="tab-panel" id="tab-templates">
                 <p class="section-tip">
                     <span data-i18n="templates.description">
@@ -69,7 +82,18 @@
                     </span>
                 </p>
                 <div id="templates-list" class="templates-grid">
-                    <div class="loading" data-i18n="templates.loading">Loading templates...</div>
+                    <div class="loading-spinner"></div>
+                </div>
+            </div>
+
+            <div class="tab-panel" id="tab-pp-templates">
+                <p class="section-tip">
+                    <span data-i18n="postprocessing.description">
+                        Processing templates define color correction and smoothing settings. Assign them to processed picture streams for consistent postprocessing across devices.
+                    </span>
+                </p>
+                <div id="pp-templates-list" class="templates-grid">
+                    <div class="loading-spinner"></div>
                 </div>
             </div>
         </div>
@@ -244,44 +268,47 @@
         </div>
     </div>
 
-    <!-- Capture Settings Modal -->
-    <div id="capture-settings-modal" class="modal">
+    <!-- Stream Settings Modal (picture stream + LED projection settings) -->
+    <div id="stream-selector-modal" class="modal">
         <div class="modal-content">
             <div class="modal-header">
-                <h2 data-i18n="settings.capture.title">🎬 Capture Settings</h2>
-                <button class="modal-close-btn" onclick="closeCaptureSettingsModal()" title="Close">&#x2715;</button>
+                <h2 data-i18n="device.stream_settings.title">📺 Stream Settings</h2>
+                <button class="modal-close-btn" onclick="closeStreamSelectorModal()" title="Close">&#x2715;</button>
             </div>
             <div class="modal-body">
-                <form id="capture-settings-form">
-                    <input type="hidden" id="capture-settings-device-id">
+                <form id="stream-selector-form">
+                    <input type="hidden" id="stream-selector-device-id">
 
                     <div class="form-group">
-                        <label for="capture-settings-display-index" data-i18n="settings.display_index">Display:</label>
-                        <select id="capture-settings-display-index"></select>
-                        <small class="input-hint" data-i18n="settings.display_index.hint">Which screen to capture for this device</small>
+                        <label for="stream-selector-stream" data-i18n="device.stream_selector.label">Assigned Picture Stream:</label>
+                        <select id="stream-selector-stream"></select>
+                        <small class="input-hint" data-i18n="device.stream_selector.hint">Select a picture stream that defines what this device captures and processes</small>
+                    </div>
+
+                    <div id="stream-selector-info" class="stream-info-panel" style="display: none;"></div>
+
+                    <div class="form-group">
+                        <label for="stream-selector-border-width" data-i18n="device.stream_settings.border_width">Border Width (px):</label>
+                        <input type="number" id="stream-selector-border-width" min="1" max="100" value="10">
+                        <small class="input-hint" data-i18n="device.stream_settings.border_width_hint">How many pixels from the screen edge to sample for LED colors (1-100)</small>
                     </div>
 
                     <div class="form-group">
-                        <label for="capture-settings-fps" data-i18n="settings.fps">Target FPS:</label>
-                        <div class="slider-row">
-                            <input type="range" id="capture-settings-fps" min="10" max="90" value="30" oninput="document.getElementById('capture-settings-fps-value').textContent = this.value">
-                            <span id="capture-settings-fps-value" class="slider-value">30</span>
-                        </div>
-                        <small class="input-hint" data-i18n="settings.fps.hint">Target frames per second (10-90)</small>
+                        <label for="stream-selector-interpolation" data-i18n="device.stream_settings.interpolation">Interpolation Mode:</label>
+                        <select id="stream-selector-interpolation">
+                            <option value="average" data-i18n="device.stream_settings.interpolation.average">Average</option>
+                            <option value="median" data-i18n="device.stream_settings.interpolation.median">Median</option>
+                            <option value="dominant" data-i18n="device.stream_settings.interpolation.dominant">Dominant</option>
+                        </select>
+                        <small class="input-hint" data-i18n="device.stream_settings.interpolation_hint">How to calculate LED color from sampled pixels</small>
                     </div>
 
-                    <div class="form-group">
-                        <label for="capture-settings-template" data-i18n="settings.capture_template">Capture Template:</label>
-                        <select id="capture-settings-template"></select>
-                        <small class="input-hint" data-i18n="settings.capture_template.hint">Screen capture engine and configuration for this device</small>
-                    </div>
-
-                    <div id="capture-settings-error" class="error-message" style="display: none;"></div>
+                    <div id="stream-selector-error" class="error-message" style="display: none;"></div>
                 </form>
             </div>
             <div class="modal-footer">
-                <button class="btn btn-icon btn-secondary" onclick="closeCaptureSettingsModal()" title="Cancel">&#x2715;</button>
-                <button class="btn btn-icon btn-primary" onclick="saveCaptureSettings()" title="Save">&#x2713;</button>
+                <button class="btn btn-icon btn-secondary" onclick="closeStreamSelectorModal()" title="Cancel">&#x2715;</button>
+                <button class="btn btn-icon btn-primary" onclick="saveStreamSelector()" title="Save">&#x2713;</button>
             </div>
         </div>
     </div>
@@ -465,6 +492,189 @@
         </div>
     </div>
 
+    <!-- Test Stream Modal -->
+    <div id="test-stream-modal" class="modal">
+        <div class="modal-content">
+            <div class="modal-header">
+                <h2 data-i18n="streams.test.title">Test Picture Stream</h2>
+                <button class="modal-close-btn" onclick="closeTestStreamModal()" title="Close">&#x2715;</button>
+            </div>
+            <div class="modal-body">
+                <div class="form-group">
+                    <label for="test-stream-duration">
+                        <span data-i18n="streams.test.duration">Capture Duration (s):</span>
+                        <span id="test-stream-duration-value">5</span>
+                    </label>
+                    <input type="range" id="test-stream-duration" min="1" max="10" step="1" value="5" oninput="updateStreamTestDuration(this.value)" />
+                </div>
+
+                <button type="button" class="btn btn-primary" onclick="runStreamTest()" style="margin-top: 16px;">
+                    <span data-i18n="streams.test.run">🧪 Run Test</span>
+                </button>
+
+                <div id="test-stream-results" style="display: none; margin-top: 16px;">
+                    <div class="test-results-container">
+                        <div class="test-preview-section">
+                            <div id="test-stream-preview-image" class="test-preview-image"></div>
+                        </div>
+
+                        <div class="test-performance-section">
+                            <div class="test-performance-stats">
+                                <div class="stat-item">
+                                    <span data-i18n="templates.test.results.duration">Duration:</span>
+                                    <strong id="test-stream-actual-duration">-</strong>
+                                </div>
+                                <div class="stat-item">
+                                    <span data-i18n="templates.test.results.frame_count">Frames:</span>
+                                    <strong id="test-stream-frame-count">-</strong>
+                                </div>
+                                <div class="stat-item">
+                                    <span data-i18n="templates.test.results.actual_fps">Actual FPS:</span>
+                                    <strong id="test-stream-actual-fps">-</strong>
+                                </div>
+                                <div class="stat-item">
+                                    <span data-i18n="templates.test.results.avg_capture_time">Avg Capture:</span>
+                                    <strong id="test-stream-avg-capture-time">-</strong>
+                                </div>
+                            </div>
+                        </div>
+                    </div>
+                </div>
+            </div>
+        </div>
+    </div>
+
+    <!-- Picture Stream Modal -->
+    <div id="stream-modal" class="modal">
+        <div class="modal-content">
+            <div class="modal-header">
+                <h2 id="stream-modal-title" data-i18n="streams.add">Add Picture Stream</h2>
+                <button class="modal-close-btn" onclick="closeStreamModal()" title="Close">&#x2715;</button>
+            </div>
+            <div class="modal-body">
+                <input type="hidden" id="stream-id">
+                <form id="stream-form">
+                    <div class="form-group">
+                        <label for="stream-name" data-i18n="streams.name">Stream Name:</label>
+                        <input type="text" id="stream-name" data-i18n-placeholder="streams.name.placeholder" placeholder="My Stream" required>
+                    </div>
+
+                    <div class="form-group">
+                        <label for="stream-type" data-i18n="streams.type">Stream Type:</label>
+                        <select id="stream-type" onchange="onStreamTypeChange()">
+                            <option value="raw" data-i18n="streams.type.raw">Screen Capture</option>
+                            <option value="processed" data-i18n="streams.type.processed">Processed</option>
+                        </select>
+                    </div>
+
+                    <!-- Raw stream fields -->
+                    <div id="stream-raw-fields">
+                        <div class="form-group">
+                            <label for="stream-display-index" data-i18n="streams.display">Display:</label>
+                            <select id="stream-display-index"></select>
+                        </div>
+                        <div class="form-group">
+                            <label for="stream-capture-template" data-i18n="streams.capture_template">Capture Template:</label>
+                            <select id="stream-capture-template"></select>
+                        </div>
+                        <div class="form-group">
+                            <label for="stream-target-fps" data-i18n="streams.target_fps">Target FPS:</label>
+                            <div class="slider-row">
+                                <input type="range" id="stream-target-fps" min="10" max="90" value="30" oninput="document.getElementById('stream-target-fps-value').textContent = this.value">
+                                <span id="stream-target-fps-value" class="slider-value">30</span>
+                            </div>
+                        </div>
+                    </div>
+
+                    <!-- Processed stream fields -->
+                    <div id="stream-processed-fields" style="display: none;">
+                        <div class="form-group">
+                            <label for="stream-source" data-i18n="streams.source">Source Stream:</label>
+                            <select id="stream-source"></select>
+                        </div>
+                        <div class="form-group">
+                            <label for="stream-pp-template" data-i18n="streams.pp_template">Processing Template:</label>
+                            <select id="stream-pp-template"></select>
+                        </div>
+                    </div>
+
+                    <div class="form-group">
+                        <label for="stream-description" data-i18n="streams.description_label">Description (optional):</label>
+                        <input type="text" id="stream-description" data-i18n-placeholder="streams.description_placeholder" placeholder="Describe this stream...">
+                    </div>
+
+                    <div id="stream-error" class="error-message" style="display: none;"></div>
+                </form>
+            </div>
+            <div class="modal-footer">
+                <button class="btn btn-icon btn-secondary" onclick="closeStreamModal()" title="Cancel">&#x2715;</button>
+                <button class="btn btn-icon btn-primary" onclick="saveStream()" title="Save">&#x2713;</button>
+            </div>
+        </div>
+    </div>
+
+    <!-- Processing Template Modal -->
+    <div id="pp-template-modal" class="modal">
+        <div class="modal-content">
+            <div class="modal-header">
+                <h2 id="pp-template-modal-title" data-i18n="postprocessing.add">Add Processing Template</h2>
+                <button class="modal-close-btn" onclick="closePPTemplateModal()" title="Close">&#x2715;</button>
+            </div>
+            <div class="modal-body">
+                <input type="hidden" id="pp-template-id">
+                <form id="pp-template-form">
+                    <div class="form-group">
+                        <label for="pp-template-name" data-i18n="postprocessing.name">Template Name:</label>
+                        <input type="text" id="pp-template-name" data-i18n-placeholder="postprocessing.name.placeholder" placeholder="My Processing Template" required>
+                    </div>
+
+                    <div class="form-group">
+                        <label for="pp-template-gamma">
+                            <span data-i18n="postprocessing.gamma">Gamma:</span>
+                            <span id="pp-template-gamma-value">2.2</span>
+                        </label>
+                        <input type="range" id="pp-template-gamma" min="0.1" max="5.0" step="0.1" value="2.2" oninput="document.getElementById('pp-template-gamma-value').textContent = this.value">
+                    </div>
+
+                    <div class="form-group">
+                        <label for="pp-template-saturation">
+                            <span data-i18n="postprocessing.saturation">Saturation:</span>
+                            <span id="pp-template-saturation-value">1.0</span>
+                        </label>
+                        <input type="range" id="pp-template-saturation" min="0.0" max="2.0" step="0.1" value="1.0" oninput="document.getElementById('pp-template-saturation-value').textContent = this.value">
+                    </div>
+
+                    <div class="form-group">
+                        <label for="pp-template-brightness">
+                            <span data-i18n="postprocessing.brightness">Brightness:</span>
+                            <span id="pp-template-brightness-value">1.0</span>
+                        </label>
+                        <input type="range" id="pp-template-brightness" min="0.0" max="1.0" step="0.05" value="1.0" oninput="document.getElementById('pp-template-brightness-value').textContent = this.value">
+                    </div>
+
+                    <div class="form-group">
+                        <label for="pp-template-smoothing">
+                            <span data-i18n="postprocessing.smoothing">Smoothing:</span>
+                            <span id="pp-template-smoothing-value">0.3</span>
+                        </label>
+                        <input type="range" id="pp-template-smoothing" min="0.0" max="1.0" step="0.05" value="0.3" oninput="document.getElementById('pp-template-smoothing-value').textContent = this.value">
+                    </div>
+
+                    <div class="form-group">
+                        <label for="pp-template-description" data-i18n="postprocessing.description_label">Description (optional):</label>
+                        <input type="text" id="pp-template-description" data-i18n-placeholder="postprocessing.description_placeholder" placeholder="Describe this template...">
+                    </div>
+
+                    <div id="pp-template-error" class="error-message" style="display: none;"></div>
+                </form>
+            </div>
+            <div class="modal-footer">
+                <button class="btn btn-icon btn-secondary" onclick="closePPTemplateModal()" title="Cancel">&#x2715;</button>
+                <button class="btn btn-icon btn-primary" onclick="savePPTemplate()" title="Save">&#x2713;</button>
+            </div>
+        </div>
+    </div>
+
     <!-- Device Tutorial Overlay (viewport-level) -->
     <div id="device-tutorial-overlay" class="tutorial-overlay tutorial-overlay-fixed">
         <div class="tutorial-backdrop"></div>

server/src/wled_controller/static/locales/en.json

@@ -50,9 +50,6 @@
   "templates.config.show": "Show configuration",
   "templates.config.none": "No additional configuration",
   "templates.config.default": "Default",
-  "templates.default": "Default",
-  "templates.custom": "Custom Templates",
-  "templates.default.locked": "Default template (cannot edit/delete)",
   "templates.created": "Template created successfully",
   "templates.updated": "Template updated successfully",
   "templates.deleted": "Template deleted successfully",
@@ -195,5 +192,69 @@
   "modal.discard_changes": "You have unsaved changes. Discard them?",
   "confirm.title": "Confirm Action",
   "confirm.yes": "Yes",
-  "confirm.no": "No"
+  "confirm.no": "No",
+  "common.delete": "Delete",
+  "common.edit": "Edit",
+  "streams.title": "\uD83D\uDCFA Picture Streams",
+  "streams.description": "Picture streams define the capture pipeline. A raw stream captures from a display using a capture template. A processed stream applies postprocessing to another stream. Assign streams to devices.",
+  "streams.add": "Add Picture Stream",
+  "streams.edit": "Edit Picture Stream",
+  "streams.name": "Stream Name:",
+  "streams.name.placeholder": "My Stream",
+  "streams.type": "Type:",
+  "streams.type.raw": "Screen Capture",
+  "streams.type.processed": "Processed",
+  "streams.display": "Display:",
+  "streams.capture_template": "Capture Template:",
+  "streams.target_fps": "Target FPS:",
+  "streams.source": "Source Stream:",
+  "streams.pp_template": "Processing Template:",
+  "streams.description_label": "Description (optional):",
+  "streams.description_placeholder": "Describe this stream...",
+  "streams.created": "Stream created successfully",
+  "streams.updated": "Stream updated successfully",
+  "streams.deleted": "Stream deleted successfully",
+  "streams.delete.confirm": "Are you sure you want to delete this stream?",
+  "streams.error.load": "Failed to load streams",
+  "streams.error.required": "Please fill in all required fields",
+  "streams.error.delete": "Failed to delete stream",
+  "streams.test.title": "Test Picture Stream",
+  "streams.test.run": "🧪 Run Test",
+  "streams.test.running": "Testing stream...",
+  "streams.test.duration": "Capture Duration (s):",
+  "streams.test.error.failed": "Stream test failed",
+  "postprocessing.title": "\uD83C\uDFA8 Processing Templates",
+  "postprocessing.description": "Processing templates define color correction and smoothing settings. Assign them to processed picture streams for consistent postprocessing across devices.",
+  "postprocessing.add": "Add Processing Template",
+  "postprocessing.edit": "Edit Processing Template",
+  "postprocessing.name": "Template Name:",
+  "postprocessing.name.placeholder": "My Processing Template",
+  "postprocessing.gamma": "Gamma:",
+  "postprocessing.saturation": "Saturation:",
+  "postprocessing.brightness": "Brightness:",
+  "postprocessing.smoothing": "Smoothing:",
+  "postprocessing.description_label": "Description (optional):",
+  "postprocessing.description_placeholder": "Describe this template...",
+  "postprocessing.created": "Template created successfully",
+  "postprocessing.updated": "Template updated successfully",
+  "postprocessing.deleted": "Template deleted successfully",
+  "postprocessing.delete.confirm": "Are you sure you want to delete this processing template?",
+  "postprocessing.error.load": "Failed to load processing templates",
+  "postprocessing.error.required": "Please fill in all required fields",
+  "postprocessing.error.delete": "Failed to delete processing template",
+  "postprocessing.config.show": "Show settings",
+  "device.button.stream_selector": "Stream Settings",
+  "device.stream_settings.title": "📺 Stream Settings",
+  "device.stream_selector.label": "Assigned Picture Stream:",
+  "device.stream_selector.hint": "Select a picture stream that defines what this device captures and processes",
+  "device.stream_selector.none": "-- No stream assigned --",
+  "device.stream_selector.saved": "Stream settings updated",
+  "device.stream_settings.border_width": "Border Width (px):",
+  "device.stream_settings.border_width_hint": "How many pixels from the screen edge to sample for LED colors (1-100)",
+  "device.stream_settings.interpolation": "Interpolation Mode:",
+  "device.stream_settings.interpolation.average": "Average",
+  "device.stream_settings.interpolation.median": "Median",
+  "device.stream_settings.interpolation.dominant": "Dominant",
+  "device.stream_settings.interpolation_hint": "How to calculate LED color from sampled pixels",
+  "device.tip.stream_selector": "Configure picture stream and LED projection settings for this device"
 }

server/src/wled_controller/static/locales/ru.json

@@ -50,9 +50,6 @@
   "templates.config.show": "Показать конфигурацию",
   "templates.config.none": "Нет дополнительных настроек",
   "templates.config.default": "По умолчанию",
-  "templates.default": "По умолчанию",
-  "templates.custom": "Пользовательские шаблоны",
-  "templates.default.locked": "Системный шаблон (нельзя редактировать/удалить)",
   "templates.created": "Шаблон успешно создан",
   "templates.updated": "Шаблон успешно обновлён",
   "templates.deleted": "Шаблон успешно удалён",
@@ -195,5 +192,69 @@
   "modal.discard_changes": "У вас есть несохранённые изменения. Отменить их?",
   "confirm.title": "Подтверждение Действия",
   "confirm.yes": "Да",
-  "confirm.no": "Нет"
+  "confirm.no": "Нет",
+  "common.delete": "Удалить",
+  "common.edit": "Редактировать",
+  "streams.title": "\uD83D\uDCFA Видеопотоки",
+  "streams.description": "Видеопотоки определяют конвейер захвата. Сырой поток захватывает экран с помощью шаблона захвата. Обработанный поток применяет постобработку к другому потоку. Назначайте потоки устройствам.",
+  "streams.add": "Добавить Видеопоток",
+  "streams.edit": "Редактировать Видеопоток",
+  "streams.name": "Имя Потока:",
+  "streams.name.placeholder": "Мой Поток",
+  "streams.type": "Тип:",
+  "streams.type.raw": "Захват экрана",
+  "streams.type.processed": "Обработанный",
+  "streams.display": "Дисплей:",
+  "streams.capture_template": "Шаблон Захвата:",
+  "streams.target_fps": "Целевой FPS:",
+  "streams.source": "Исходный Поток:",
+  "streams.pp_template": "Шаблон Обработки:",
+  "streams.description_label": "Описание (необязательно):",
+  "streams.description_placeholder": "Опишите этот поток...",
+  "streams.created": "Поток успешно создан",
+  "streams.updated": "Поток успешно обновлён",
+  "streams.deleted": "Поток успешно удалён",
+  "streams.delete.confirm": "Вы уверены, что хотите удалить этот поток?",
+  "streams.error.load": "Не удалось загрузить потоки",
+  "streams.error.required": "Пожалуйста, заполните все обязательные поля",
+  "streams.error.delete": "Не удалось удалить поток",
+  "streams.test.title": "Тест Видеопотока",
+  "streams.test.run": "🧪 Запустить Тест",
+  "streams.test.running": "Тестирование потока...",
+  "streams.test.duration": "Длительность Захвата (с):",
+  "streams.test.error.failed": "Тест потока не удался",
+  "postprocessing.title": "\uD83C\uDFA8 Шаблоны Обработки",
+  "postprocessing.description": "Шаблоны обработки определяют настройки цветокоррекции и сглаживания. Назначайте их обработанным видеопотокам для единообразной постобработки на всех устройствах.",
+  "postprocessing.add": "Добавить Шаблон Обработки",
+  "postprocessing.edit": "Редактировать Шаблон Обработки",
+  "postprocessing.name": "Имя Шаблона:",
+  "postprocessing.name.placeholder": "Мой Шаблон Обработки",
+  "postprocessing.gamma": "Гамма:",
+  "postprocessing.saturation": "Насыщенность:",
+  "postprocessing.brightness": "Яркость:",
+  "postprocessing.smoothing": "Сглаживание:",
+  "postprocessing.description_label": "Описание (необязательно):",
+  "postprocessing.description_placeholder": "Опишите этот шаблон...",
+  "postprocessing.created": "Шаблон успешно создан",
+  "postprocessing.updated": "Шаблон успешно обновлён",
+  "postprocessing.deleted": "Шаблон успешно удалён",
+  "postprocessing.delete.confirm": "Вы уверены, что хотите удалить этот шаблон обработки?",
+  "postprocessing.error.load": "Не удалось загрузить шаблоны обработки",
+  "postprocessing.error.required": "Пожалуйста, заполните все обязательные поля",
+  "postprocessing.error.delete": "Не удалось удалить шаблон обработки",
+  "postprocessing.config.show": "Показать настройки",
+  "device.button.stream_selector": "Настройки потока",
+  "device.stream_settings.title": "📺 Настройки потока",
+  "device.stream_selector.label": "Назначенный Видеопоток:",
+  "device.stream_selector.hint": "Выберите видеопоток, определяющий что это устройство захватывает и обрабатывает",
+  "device.stream_selector.none": "-- Поток не назначен --",
+  "device.stream_selector.saved": "Настройки потока обновлены",
+  "device.stream_settings.border_width": "Ширина границы (px):",
+  "device.stream_settings.border_width_hint": "Сколько пикселей от края экрана выбирать для цвета LED (1-100)",
+  "device.stream_settings.interpolation": "Режим интерполяции:",
+  "device.stream_settings.interpolation.average": "Среднее",
+  "device.stream_settings.interpolation.median": "Медиана",
+  "device.stream_settings.interpolation.dominant": "Доминантный",
+  "device.stream_settings.interpolation_hint": "Как вычислять цвет LED из выбранных пикселей",
+  "device.tip.stream_selector": "Настройки видеопотока и проекции LED для этого устройства"
 }

server/src/wled_controller/static/style.css

@@ -165,7 +165,8 @@ section {
     gap: 20px;
 }
 
-.devices-grid > .loading {
+.devices-grid > .loading,
+.devices-grid > .loading-spinner {
     grid-column: 1 / -1;
 }
 
@@ -735,6 +736,27 @@ input:-webkit-autofill:focus {
     color: #999;
 }
 
+.loading-spinner {
+    display: flex;
+    justify-content: center;
+    align-items: center;
+    padding: 40px;
+}
+
+.loading-spinner::after {
+    content: '';
+    width: 28px;
+    height: 28px;
+    border: 3px solid var(--border-color);
+    border-top-color: var(--primary-color);
+    border-radius: 50%;
+    animation: spin 0.8s linear infinite;
+}
+
+@keyframes spin {
+    to { transform: rotate(360deg); }
+}
+
 /* Full-page overlay spinner */
 .overlay-spinner {
     position: fixed;
@@ -1740,24 +1762,6 @@ input:-webkit-autofill:focus {
     gap: 20px;
 }
 
-.templates-separator {
-    grid-column: 1 / -1;
-    display: flex;
-    align-items: center;
-    gap: 12px;
-    color: var(--text-secondary);
-    font-size: 0.85rem;
-    font-weight: 500;
-}
-
-.templates-separator::before,
-.templates-separator::after {
-    content: '';
-    flex: 1;
-    height: 1px;
-    background: var(--border-color);
-}
-
 .template-card {
     background: var(--card-bg);
     border: 1px solid var(--border-color);
@@ -1815,6 +1819,9 @@ input:-webkit-autofill:focus {
     justify-content: space-between;
     align-items: center;
     margin-bottom: 12px;
+}
+
+.template-card .template-card-header {
     padding-right: 24px;
 }
 
@@ -1832,11 +1839,6 @@ input:-webkit-autofill:focus {
     text-transform: uppercase;
 }
 
-.badge-default {
-    background: var(--primary-color);
-    color: white;
-}
-
 .template-description {
     color: var(--text-secondary);
     font-size: 14px;
@@ -2013,6 +2015,36 @@ input:-webkit-autofill:focus {
     font-size: 16px;
 }
 
+/* Stream type badges */
+.badge-raw {
+    background: #1976d2;
+    color: white;
+}
+
+.badge-processed {
+    background: #7b1fa2;
+    color: white;
+}
+
+/* Stream info panel in stream selector modal */
+.stream-info-panel {
+    background: var(--bg-secondary, #2a2a2a);
+    border: 1px solid var(--border-color);
+    border-radius: 8px;
+    padding: 12px 16px;
+    margin-top: 12px;
+    font-size: 14px;
+    line-height: 1.6;
+}
+
+.stream-info-panel div {
+    margin-bottom: 4px;
+}
+
+.stream-info-panel strong {
+    margin-right: 6px;
+}
+
 /* Responsive adjustments */
 @media (max-width: 768px) {
     .templates-grid {

server/src/wled_controller/storage/__init__.py

@@ -1,5 +1,7 @@
 """Storage layer for device and configuration persistence."""
 
 from .device_store import DeviceStore
+from .picture_stream_store import PictureStreamStore
+from .postprocessing_template_store import PostprocessingTemplateStore
 
-__all__ = ["DeviceStore"]
+__all__ = ["DeviceStore", "PictureStreamStore", "PostprocessingTemplateStore"]

server/src/wled_controller/storage/device_store.py

@@ -30,7 +30,8 @@ class Device:
         enabled: bool = True,
         settings: Optional[ProcessingSettings] = None,
         calibration: Optional[CalibrationConfig] = None,
-        capture_template_id: str = "tpl_mss_default",
+        capture_template_id: str = "",
+        picture_stream_id: str = "",
         created_at: Optional[datetime] = None,
         updated_at: Optional[datetime] = None,
     ):
@@ -44,7 +45,8 @@ class Device:
             enabled: Whether device is enabled
             settings: Processing settings
             calibration: Calibration configuration
-            capture_template_id: ID of assigned capture template
+            capture_template_id: ID of assigned capture template (legacy, use picture_stream_id)
+            picture_stream_id: ID of assigned picture stream
             created_at: Creation timestamp
             updated_at: Last update timestamp
         """
@@ -56,6 +58,7 @@ class Device:
         self.settings = settings or ProcessingSettings()
         self.calibration = calibration or create_default_calibration(led_count)
         self.capture_template_id = capture_template_id
+        self.picture_stream_id = picture_stream_id
         self.created_at = created_at or datetime.utcnow()
         self.updated_at = updated_at or datetime.utcnow()
 
@@ -84,6 +87,7 @@ class Device:
             },
             "calibration": calibration_to_dict(self.calibration),
             "capture_template_id": self.capture_template_id,
+            "picture_stream_id": self.picture_stream_id,
             "created_at": self.created_at.isoformat(),
             "updated_at": self.updated_at.isoformat(),
         }
@@ -121,11 +125,8 @@ class Device:
             else create_default_calibration(data["led_count"])
         )
 
-        # Migration: assign default MSS template if no template set
-        capture_template_id = data.get("capture_template_id")
-        if not capture_template_id:
-            capture_template_id = "tpl_mss_default"
-            logger.info(f"Migrating device {data['id']} to default MSS template")
+        capture_template_id = data.get("capture_template_id", "")
+        picture_stream_id = data.get("picture_stream_id", "")
 
         return cls(
             device_id=data["id"],
@@ -136,6 +137,7 @@ class Device:
             settings=settings,
             calibration=calibration,
             capture_template_id=capture_template_id,
+            picture_stream_id=picture_stream_id,
             created_at=datetime.fromisoformat(data.get("created_at", datetime.utcnow().isoformat())),
             updated_at=datetime.fromisoformat(data.get("updated_at", datetime.utcnow().isoformat())),
         )
@@ -217,7 +219,8 @@ class DeviceStore:
         led_count: int,
         settings: Optional[ProcessingSettings] = None,
         calibration: Optional[CalibrationConfig] = None,
-        capture_template_id: str = "tpl_mss_default",
+        capture_template_id: str = "",
+        picture_stream_id: str = "",
     ) -> Device:
         """Create a new device.
 
@@ -247,6 +250,7 @@ class DeviceStore:
             settings=settings,
             calibration=calibration,
             capture_template_id=capture_template_id,
+            picture_stream_id=picture_stream_id,
         )
 
         # Store
@@ -285,6 +289,7 @@ class DeviceStore:
         settings: Optional[ProcessingSettings] = None,
         calibration: Optional[CalibrationConfig] = None,
         capture_template_id: Optional[str] = None,
+        picture_stream_id: Optional[str] = None,
     ) -> Device:
         """Update device.
 
@@ -331,6 +336,8 @@ class DeviceStore:
             device.calibration = calibration
         if capture_template_id is not None:
             device.capture_template_id = capture_template_id
+        if picture_stream_id is not None:
+            device.picture_stream_id = picture_stream_id
 
         device.updated_at = datetime.utcnow()
 

server/src/wled_controller/storage/picture_stream.py

@@ -0,0 +1,69 @@
+"""Picture stream data model."""
+
+from dataclasses import dataclass
+from datetime import datetime
+from typing import Optional
+
+
+@dataclass
+class PictureStream:
+    """Represents a picture stream configuration.
+
+    A picture stream is either:
+    - "raw": captures from a display using a capture engine template at a target FPS
+    - "processed": applies postprocessing to another picture stream
+    """
+
+    id: str
+    name: str
+    stream_type: str  # "raw" or "processed"
+    created_at: datetime
+    updated_at: datetime
+
+    # Raw stream fields (used when stream_type == "raw")
+    display_index: Optional[int] = None
+    capture_template_id: Optional[str] = None
+    target_fps: Optional[int] = None
+
+    # Processed stream fields (used when stream_type == "processed")
+    source_stream_id: Optional[str] = None
+    postprocessing_template_id: Optional[str] = None
+
+    description: Optional[str] = None
+
+    def to_dict(self) -> dict:
+        """Convert stream to dictionary."""
+        return {
+            "id": self.id,
+            "name": self.name,
+            "stream_type": self.stream_type,
+            "display_index": self.display_index,
+            "capture_template_id": self.capture_template_id,
+            "target_fps": self.target_fps,
+            "source_stream_id": self.source_stream_id,
+            "postprocessing_template_id": self.postprocessing_template_id,
+            "created_at": self.created_at.isoformat(),
+            "updated_at": self.updated_at.isoformat(),
+            "description": self.description,
+        }
+
+    @classmethod
+    def from_dict(cls, data: dict) -> "PictureStream":
+        """Create stream from dictionary."""
+        return cls(
+            id=data["id"],
+            name=data["name"],
+            stream_type=data["stream_type"],
+            display_index=data.get("display_index"),
+            capture_template_id=data.get("capture_template_id"),
+            target_fps=data.get("target_fps"),
+            source_stream_id=data.get("source_stream_id"),
+            postprocessing_template_id=data.get("postprocessing_template_id"),
+            created_at=datetime.fromisoformat(data["created_at"])
+            if isinstance(data.get("created_at"), str)
+            else data.get("created_at", datetime.utcnow()),
+            updated_at=datetime.fromisoformat(data["updated_at"])
+            if isinstance(data.get("updated_at"), str)
+            else data.get("updated_at", datetime.utcnow()),
+            description=data.get("description"),
+        )

server/src/wled_controller/storage/picture_stream_store.py

@@ -0,0 +1,332 @@
+"""Picture stream storage using JSON files."""
+
+import json
+import uuid
+from datetime import datetime
+from pathlib import Path
+from typing import Dict, List, Optional, Set
+
+from wled_controller.storage.picture_stream import PictureStream
+from wled_controller.utils import get_logger
+
+logger = get_logger(__name__)
+
+
+class PictureStreamStore:
+    """Storage for picture streams.
+
+    Supports raw and processed stream types with cycle detection
+    for processed streams that reference other streams.
+    """
+
+    def __init__(self, file_path: str):
+        """Initialize picture stream store.
+
+        Args:
+            file_path: Path to streams JSON file
+        """
+        self.file_path = Path(file_path)
+        self._streams: Dict[str, PictureStream] = {}
+        self._load()
+
+    def _load(self) -> None:
+        """Load streams from file."""
+        if not self.file_path.exists():
+            return
+
+        try:
+            with open(self.file_path, "r", encoding="utf-8") as f:
+                data = json.load(f)
+
+            streams_data = data.get("picture_streams", {})
+            loaded = 0
+            for stream_id, stream_dict in streams_data.items():
+                try:
+                    stream = PictureStream.from_dict(stream_dict)
+                    self._streams[stream_id] = stream
+                    loaded += 1
+                except Exception as e:
+                    logger.error(
+                        f"Failed to load picture stream {stream_id}: {e}",
+                        exc_info=True,
+                    )
+
+            if loaded > 0:
+                logger.info(f"Loaded {loaded} picture streams from storage")
+
+        except Exception as e:
+            logger.error(f"Failed to load picture streams from {self.file_path}: {e}")
+            raise
+
+        logger.info(f"Picture stream store initialized with {len(self._streams)} streams")
+
+    def _save(self) -> None:
+        """Save all streams to file."""
+        try:
+            self.file_path.parent.mkdir(parents=True, exist_ok=True)
+
+            streams_dict = {
+                stream_id: stream.to_dict()
+                for stream_id, stream in self._streams.items()
+            }
+
+            data = {
+                "version": "1.0.0",
+                "picture_streams": streams_dict,
+            }
+
+            with open(self.file_path, "w", encoding="utf-8") as f:
+                json.dump(data, f, indent=2, ensure_ascii=False)
+
+        except Exception as e:
+            logger.error(f"Failed to save picture streams to {self.file_path}: {e}")
+            raise
+
+    def _detect_cycle(self, source_stream_id: str, exclude_stream_id: Optional[str] = None) -> bool:
+        """Detect if following the source chain from source_stream_id would create a cycle.
+
+        Args:
+            source_stream_id: The source stream ID to start walking from
+            exclude_stream_id: Stream ID to exclude (the stream being created/updated)
+
+        Returns:
+            True if a cycle would be created
+        """
+        visited: Set[str] = set()
+        if exclude_stream_id:
+            visited.add(exclude_stream_id)
+
+        current_id = source_stream_id
+        while current_id:
+            if current_id in visited:
+                return True
+            visited.add(current_id)
+
+            current_stream = self._streams.get(current_id)
+            if not current_stream:
+                break
+            if current_stream.stream_type == "raw":
+                break
+            current_id = current_stream.source_stream_id
+
+        return False
+
+    def get_all_streams(self) -> List[PictureStream]:
+        """Get all picture streams."""
+        return list(self._streams.values())
+
+    def get_stream(self, stream_id: str) -> PictureStream:
+        """Get stream by ID.
+
+        Raises:
+            ValueError: If stream not found
+        """
+        if stream_id not in self._streams:
+            raise ValueError(f"Picture stream not found: {stream_id}")
+        return self._streams[stream_id]
+
+    def create_stream(
+        self,
+        name: str,
+        stream_type: str,
+        display_index: Optional[int] = None,
+        capture_template_id: Optional[str] = None,
+        target_fps: Optional[int] = None,
+        source_stream_id: Optional[str] = None,
+        postprocessing_template_id: Optional[str] = None,
+        description: Optional[str] = None,
+    ) -> PictureStream:
+        """Create a new picture stream.
+
+        Args:
+            name: Stream name
+            stream_type: "raw" or "processed"
+            display_index: Display index (raw streams)
+            capture_template_id: Capture template ID (raw streams)
+            target_fps: Target FPS (raw streams)
+            source_stream_id: Source stream ID (processed streams)
+            postprocessing_template_id: Postprocessing template ID (processed streams)
+            description: Optional description
+
+        Raises:
+            ValueError: If validation fails or cycle detected
+        """
+        if stream_type not in ("raw", "processed"):
+            raise ValueError(f"Invalid stream type: {stream_type}")
+
+        if stream_type == "raw":
+            if display_index is None:
+                raise ValueError("Raw streams require display_index")
+            if not capture_template_id:
+                raise ValueError("Raw streams require capture_template_id")
+            if target_fps is None:
+                raise ValueError("Raw streams require target_fps")
+        elif stream_type == "processed":
+            if not source_stream_id:
+                raise ValueError("Processed streams require source_stream_id")
+            if not postprocessing_template_id:
+                raise ValueError("Processed streams require postprocessing_template_id")
+            # Validate source stream exists
+            if source_stream_id not in self._streams:
+                raise ValueError(f"Source stream not found: {source_stream_id}")
+            # Check for cycles
+            if self._detect_cycle(source_stream_id):
+                raise ValueError("Cycle detected in stream chain")
+
+        # Check for duplicate name
+        for stream in self._streams.values():
+            if stream.name == name:
+                raise ValueError(f"Picture stream with name '{name}' already exists")
+
+        stream_id = f"ps_{uuid.uuid4().hex[:8]}"
+        now = datetime.utcnow()
+
+        stream = PictureStream(
+            id=stream_id,
+            name=name,
+            stream_type=stream_type,
+            display_index=display_index,
+            capture_template_id=capture_template_id,
+            target_fps=target_fps,
+            source_stream_id=source_stream_id,
+            postprocessing_template_id=postprocessing_template_id,
+            created_at=now,
+            updated_at=now,
+            description=description,
+        )
+
+        self._streams[stream_id] = stream
+        self._save()
+
+        logger.info(f"Created picture stream: {name} ({stream_id}, type={stream_type})")
+        return stream
+
+    def update_stream(
+        self,
+        stream_id: str,
+        name: Optional[str] = None,
+        display_index: Optional[int] = None,
+        capture_template_id: Optional[str] = None,
+        target_fps: Optional[int] = None,
+        source_stream_id: Optional[str] = None,
+        postprocessing_template_id: Optional[str] = None,
+        description: Optional[str] = None,
+    ) -> PictureStream:
+        """Update an existing picture stream.
+
+        Raises:
+            ValueError: If stream not found, validation fails, or cycle detected
+        """
+        if stream_id not in self._streams:
+            raise ValueError(f"Picture stream not found: {stream_id}")
+
+        stream = self._streams[stream_id]
+
+        # If changing source_stream_id on a processed stream, check for cycles
+        if source_stream_id is not None and stream.stream_type == "processed":
+            if source_stream_id not in self._streams:
+                raise ValueError(f"Source stream not found: {source_stream_id}")
+            if self._detect_cycle(source_stream_id, exclude_stream_id=stream_id):
+                raise ValueError("Cycle detected in stream chain")
+
+        if name is not None:
+            stream.name = name
+        if display_index is not None:
+            stream.display_index = display_index
+        if capture_template_id is not None:
+            stream.capture_template_id = capture_template_id
+        if target_fps is not None:
+            stream.target_fps = target_fps
+        if source_stream_id is not None:
+            stream.source_stream_id = source_stream_id
+        if postprocessing_template_id is not None:
+            stream.postprocessing_template_id = postprocessing_template_id
+        if description is not None:
+            stream.description = description
+
+        stream.updated_at = datetime.utcnow()
+
+        self._save()
+
+        logger.info(f"Updated picture stream: {stream_id}")
+        return stream
+
+    def delete_stream(self, stream_id: str) -> None:
+        """Delete a picture stream.
+
+        Raises:
+            ValueError: If stream not found or is referenced by another stream
+        """
+        if stream_id not in self._streams:
+            raise ValueError(f"Picture stream not found: {stream_id}")
+
+        # Check if any other stream references this one as source
+        for other_stream in self._streams.values():
+            if other_stream.source_stream_id == stream_id:
+                raise ValueError(
+                    f"Cannot delete stream '{self._streams[stream_id].name}': "
+                    f"it is referenced by stream '{other_stream.name}'"
+                )
+
+        del self._streams[stream_id]
+        self._save()
+
+        logger.info(f"Deleted picture stream: {stream_id}")
+
+    def is_referenced_by_device(self, stream_id: str, device_store) -> bool:
+        """Check if this stream is referenced by any device.
+
+        Args:
+            stream_id: Stream ID to check
+            device_store: DeviceStore instance
+
+        Returns:
+            True if any device references this stream
+        """
+        for device in device_store.get_all_devices():
+            if getattr(device, "picture_stream_id", None) == stream_id:
+                return True
+        return False
+
+    def resolve_stream_chain(self, stream_id: str) -> dict:
+        """Resolve a stream chain to get the final raw stream and collected postprocessing templates.
+
+        Walks the chain from the given stream to the root raw stream,
+        collecting postprocessing template IDs along the way.
+
+        Args:
+            stream_id: Starting stream ID
+
+        Returns:
+            Dict with:
+                - raw_stream: The root raw PictureStream
+                - postprocessing_template_ids: List of PP template IDs (in chain order)
+
+        Raises:
+            ValueError: If stream not found or chain is broken
+        """
+        postprocessing_template_ids = []
+        visited = set()
+        current_id = stream_id
+
+        while True:
+            if current_id in visited:
+                raise ValueError(f"Cycle detected in stream chain at {current_id}")
+            visited.add(current_id)
+
+            stream = self.get_stream(current_id)
+
+            if stream.stream_type == "raw":
+                return {
+                    "raw_stream": stream,
+                    "postprocessing_template_ids": postprocessing_template_ids,
+                }
+
+            # Processed stream — collect PP template and follow source
+            if stream.postprocessing_template_id:
+                postprocessing_template_ids.append(stream.postprocessing_template_id)
+
+            if not stream.source_stream_id:
+                raise ValueError(f"Processed stream {current_id} has no source_stream_id")
+
+            current_id = stream.source_stream_id

server/src/wled_controller/storage/postprocessing_template.py

@@ -0,0 +1,53 @@
+"""Postprocessing template data model."""
+
+from dataclasses import dataclass
+from datetime import datetime
+from typing import Optional
+
+
+@dataclass
+class PostprocessingTemplate:
+    """Postprocessing settings template for color correction and smoothing."""
+
+    id: str
+    name: str
+    gamma: float
+    saturation: float
+    brightness: float
+    smoothing: float
+    created_at: datetime
+    updated_at: datetime
+    description: Optional[str] = None
+
+    def to_dict(self) -> dict:
+        """Convert template to dictionary."""
+        return {
+            "id": self.id,
+            "name": self.name,
+            "gamma": self.gamma,
+            "saturation": self.saturation,
+            "brightness": self.brightness,
+            "smoothing": self.smoothing,
+            "created_at": self.created_at.isoformat(),
+            "updated_at": self.updated_at.isoformat(),
+            "description": self.description,
+        }
+
+    @classmethod
+    def from_dict(cls, data: dict) -> "PostprocessingTemplate":
+        """Create template from dictionary."""
+        return cls(
+            id=data["id"],
+            name=data["name"],
+            gamma=data.get("gamma", 2.2),
+            saturation=data.get("saturation", 1.0),
+            brightness=data.get("brightness", 1.0),
+            smoothing=data.get("smoothing", 0.3),
+            created_at=datetime.fromisoformat(data["created_at"])
+            if isinstance(data.get("created_at"), str)
+            else data.get("created_at", datetime.utcnow()),
+            updated_at=datetime.fromisoformat(data["updated_at"])
+            if isinstance(data.get("updated_at"), str)
+            else data.get("updated_at", datetime.utcnow()),
+            description=data.get("description"),
+        )

server/src/wled_controller/storage/postprocessing_template_store.py

@@ -0,0 +1,230 @@
+"""Postprocessing template storage using JSON files."""
+
+import json
+import uuid
+from datetime import datetime
+from pathlib import Path
+from typing import Dict, List, Optional
+
+from wled_controller.storage.postprocessing_template import PostprocessingTemplate
+from wled_controller.utils import get_logger
+
+logger = get_logger(__name__)
+
+
+class PostprocessingTemplateStore:
+    """Storage for postprocessing templates.
+
+    All templates are persisted to the JSON file.
+    On startup, if no templates exist, a default one is auto-created.
+    """
+
+    def __init__(self, file_path: str):
+        """Initialize postprocessing template store.
+
+        Args:
+            file_path: Path to templates JSON file
+        """
+        self.file_path = Path(file_path)
+        self._templates: Dict[str, PostprocessingTemplate] = {}
+        self._load()
+        self._ensure_initial_template()
+
+    def _ensure_initial_template(self) -> None:
+        """Auto-create a default postprocessing template if none exist."""
+        if self._templates:
+            return
+
+        now = datetime.utcnow()
+        template_id = f"pp_{uuid.uuid4().hex[:8]}"
+
+        template = PostprocessingTemplate(
+            id=template_id,
+            name="Default",
+            gamma=2.2,
+            saturation=1.0,
+            brightness=1.0,
+            smoothing=0.3,
+            created_at=now,
+            updated_at=now,
+            description="Default postprocessing template",
+        )
+
+        self._templates[template_id] = template
+        self._save()
+        logger.info(f"Auto-created initial postprocessing template: {template.name} ({template_id})")
+
+    def _load(self) -> None:
+        """Load templates from file."""
+        if not self.file_path.exists():
+            return
+
+        try:
+            with open(self.file_path, "r", encoding="utf-8") as f:
+                data = json.load(f)
+
+            templates_data = data.get("postprocessing_templates", {})
+            loaded = 0
+            for template_id, template_dict in templates_data.items():
+                try:
+                    template = PostprocessingTemplate.from_dict(template_dict)
+                    self._templates[template_id] = template
+                    loaded += 1
+                except Exception as e:
+                    logger.error(
+                        f"Failed to load postprocessing template {template_id}: {e}",
+                        exc_info=True,
+                    )
+
+            if loaded > 0:
+                logger.info(f"Loaded {loaded} postprocessing templates from storage")
+
+        except Exception as e:
+            logger.error(f"Failed to load postprocessing templates from {self.file_path}: {e}")
+            raise
+
+        logger.info(f"Postprocessing template store initialized with {len(self._templates)} templates")
+
+    def _save(self) -> None:
+        """Save all templates to file."""
+        try:
+            self.file_path.parent.mkdir(parents=True, exist_ok=True)
+
+            templates_dict = {
+                template_id: template.to_dict()
+                for template_id, template in self._templates.items()
+            }
+
+            data = {
+                "version": "1.0.0",
+                "postprocessing_templates": templates_dict,
+            }
+
+            with open(self.file_path, "w", encoding="utf-8") as f:
+                json.dump(data, f, indent=2, ensure_ascii=False)
+
+        except Exception as e:
+            logger.error(f"Failed to save postprocessing templates to {self.file_path}: {e}")
+            raise
+
+    def get_all_templates(self) -> List[PostprocessingTemplate]:
+        """Get all postprocessing templates."""
+        return list(self._templates.values())
+
+    def get_template(self, template_id: str) -> PostprocessingTemplate:
+        """Get template by ID.
+
+        Raises:
+            ValueError: If template not found
+        """
+        if template_id not in self._templates:
+            raise ValueError(f"Postprocessing template not found: {template_id}")
+        return self._templates[template_id]
+
+    def create_template(
+        self,
+        name: str,
+        gamma: float = 2.2,
+        saturation: float = 1.0,
+        brightness: float = 1.0,
+        smoothing: float = 0.3,
+        description: Optional[str] = None,
+    ) -> PostprocessingTemplate:
+        """Create a new postprocessing template.
+
+        Raises:
+            ValueError: If template with same name exists
+        """
+        for template in self._templates.values():
+            if template.name == name:
+                raise ValueError(f"Postprocessing template with name '{name}' already exists")
+
+        template_id = f"pp_{uuid.uuid4().hex[:8]}"
+        now = datetime.utcnow()
+
+        template = PostprocessingTemplate(
+            id=template_id,
+            name=name,
+            gamma=gamma,
+            saturation=saturation,
+            brightness=brightness,
+            smoothing=smoothing,
+            created_at=now,
+            updated_at=now,
+            description=description,
+        )
+
+        self._templates[template_id] = template
+        self._save()
+
+        logger.info(f"Created postprocessing template: {name} ({template_id})")
+        return template
+
+    def update_template(
+        self,
+        template_id: str,
+        name: Optional[str] = None,
+        gamma: Optional[float] = None,
+        saturation: Optional[float] = None,
+        brightness: Optional[float] = None,
+        smoothing: Optional[float] = None,
+        description: Optional[str] = None,
+    ) -> PostprocessingTemplate:
+        """Update an existing postprocessing template.
+
+        Raises:
+            ValueError: If template not found
+        """
+        if template_id not in self._templates:
+            raise ValueError(f"Postprocessing template not found: {template_id}")
+
+        template = self._templates[template_id]
+
+        if name is not None:
+            template.name = name
+        if gamma is not None:
+            template.gamma = gamma
+        if saturation is not None:
+            template.saturation = saturation
+        if brightness is not None:
+            template.brightness = brightness
+        if smoothing is not None:
+            template.smoothing = smoothing
+        if description is not None:
+            template.description = description
+
+        template.updated_at = datetime.utcnow()
+
+        self._save()
+
+        logger.info(f"Updated postprocessing template: {template_id}")
+        return template
+
+    def delete_template(self, template_id: str) -> None:
+        """Delete a postprocessing template.
+
+        Raises:
+            ValueError: If template not found or is referenced by a picture stream
+        """
+        if template_id not in self._templates:
+            raise ValueError(f"Postprocessing template not found: {template_id}")
+
+        del self._templates[template_id]
+        self._save()
+
+        logger.info(f"Deleted postprocessing template: {template_id}")
+
+    def is_referenced_by(self, template_id: str, picture_stream_store) -> bool:
+        """Check if this template is referenced by any picture stream.
+
+        Args:
+            template_id: Template ID to check
+            picture_stream_store: PictureStreamStore instance
+
+        Returns:
+            True if any picture stream references this template
+        """
+        for stream in picture_stream_store.get_all_streams():
+            if stream.postprocessing_template_id == template_id:
+                return True
+        return False

server/src/wled_controller/storage/template.py

@@ -13,7 +13,6 @@ class CaptureTemplate:
     name: str
     engine_type: str
     engine_config: Dict[str, Any]
-    is_default: bool
     created_at: datetime
     updated_at: datetime
     description: Optional[str] = None
@@ -29,7 +28,6 @@ class CaptureTemplate:
             "name": self.name,
             "engine_type": self.engine_type,
             "engine_config": self.engine_config,
-            "is_default": self.is_default,
             "created_at": self.created_at.isoformat(),
             "updated_at": self.updated_at.isoformat(),
             "description": self.description,
@@ -50,7 +48,6 @@ class CaptureTemplate:
             name=data["name"],
             engine_type=data["engine_type"],
             engine_config=data.get("engine_config", {}),
-            is_default=data.get("is_default", False),
             created_at=datetime.fromisoformat(data["created_at"])
             if isinstance(data.get("created_at"), str)
             else data.get("created_at", datetime.utcnow()),

server/src/wled_controller/storage/template_store.py

@@ -16,8 +16,9 @@ logger = get_logger(__name__)
 class TemplateStore:
     """Storage for capture templates.
 
-    Default templates for each available engine are created in memory at startup.
-    Only user-created templates are persisted to the JSON file.
+    All templates are persisted to the JSON file.
+    On startup, if no templates exist, one is auto-created using the
+    highest-priority available engine.
     """
 
     def __init__(self, file_path: str):
@@ -28,34 +29,40 @@ class TemplateStore:
         """
         self.file_path = Path(file_path)
         self._templates: Dict[str, CaptureTemplate] = {}
-        self._ensure_defaults()
         self._load()
+        self._ensure_initial_template()
 
-    def _ensure_defaults(self) -> None:
-        """Create default templates in memory for all available engines."""
-        available = EngineRegistry.get_available_engines()
+    def _ensure_initial_template(self) -> None:
+        """Auto-create a template if none exist, using the best available engine."""
+        if self._templates:
+            return
+
+        best_engine = EngineRegistry.get_best_available_engine()
+        if not best_engine:
+            logger.warning("No capture engines available, cannot create initial template")
+            return
+
+        engine_class = EngineRegistry.get_engine(best_engine)
+        default_config = engine_class.get_default_config()
         now = datetime.utcnow()
+        template_id = f"tpl_{uuid.uuid4().hex[:8]}"
 
-        for engine_type in available:
-            template_id = f"tpl_{engine_type}_default"
-            engine_class = EngineRegistry.get_engine(engine_type)
-            default_config = engine_class.get_default_config()
+        template = CaptureTemplate(
+            id=template_id,
+            name=best_engine.upper(),
+            engine_type=best_engine,
+            engine_config=default_config,
+            created_at=now,
+            updated_at=now,
+            description=f"Auto-created {best_engine.upper()} template",
+        )
 
-            self._templates[template_id] = CaptureTemplate(
-                id=template_id,
-                name=engine_type.upper(),
-                engine_type=engine_type,
-                engine_config=default_config,
-                is_default=True,
-                created_at=now,
-                updated_at=now,
-                description=f"Default {engine_type} capture template",
-            )
-
-        logger.info(f"Created {len(available)} default templates in memory")
+        self._templates[template_id] = template
+        self._save()
+        logger.info(f"Auto-created initial template: {template.name} ({template_id}, engine={best_engine})")
 
     def _load(self) -> None:
-        """Load user-created templates from file."""
+        """Load templates from file."""
         if not self.file_path.exists():
             return
 
@@ -66,9 +73,6 @@ class TemplateStore:
             templates_data = data.get("templates", {})
             loaded = 0
             for template_id, template_dict in templates_data.items():
-                # Skip any default templates that may exist in old files
-                if template_dict.get("is_default", False):
-                    continue
                 try:
                     template = CaptureTemplate.from_dict(template_dict)
                     self._templates[template_id] = template
@@ -80,26 +84,23 @@ class TemplateStore:
                     )
 
             if loaded > 0:
-                logger.info(f"Loaded {loaded} user templates from storage")
+                logger.info(f"Loaded {loaded} templates from storage")
 
         except Exception as e:
             logger.error(f"Failed to load templates from {self.file_path}: {e}")
             raise
 
-        total = len(self._templates)
-        logger.info(f"Template store initialized with {total} templates")
+        logger.info(f"Template store initialized with {len(self._templates)} templates")
 
     def _save(self) -> None:
-        """Save only user-created templates to file."""
+        """Save all templates to file."""
         try:
             # Ensure directory exists
             self.file_path.parent.mkdir(parents=True, exist_ok=True)
 
-            # Only persist non-default templates
             templates_dict = {
                 template_id: template.to_dict()
                 for template_id, template in self._templates.items()
-                if not template.is_default
             }
 
             data = {
@@ -162,7 +163,7 @@ class TemplateStore:
         """
         # Check for duplicate name
         for template in self._templates.values():
-            if template.name == name and not template.is_default:
+            if template.name == name:
                 raise ValueError(f"Template with name '{name}' already exists")
 
         # Generate new ID
@@ -175,7 +176,6 @@ class TemplateStore:
             name=name,
             engine_type=engine_type,
             engine_config=engine_config,
-            is_default=False,
             created_at=now,
             updated_at=now,
             description=description,
@@ -209,16 +209,13 @@ class TemplateStore:
             Updated template
 
         Raises:
-            ValueError: If template not found or is a default template
+            ValueError: If template not found
         """
         if template_id not in self._templates:
             raise ValueError(f"Template not found: {template_id}")
 
         template = self._templates[template_id]
 
-        if template.is_default:
-            raise ValueError("Cannot modify default templates")
-
         # Update fields
         if name is not None:
             template.name = name
@@ -244,16 +241,11 @@ class TemplateStore:
             template_id: Template ID
 
         Raises:
-            ValueError: If template not found or is a default template
+            ValueError: If template not found
         """
         if template_id not in self._templates:
             raise ValueError(f"Template not found: {template_id}")
 
-        template = self._templates[template_id]
-
-        if template.is_default:
-            raise ValueError("Cannot delete default templates")
-
         # Remove and save
         del self._templates[template_id]
         self._save()