Add configurable FPS to test preview and fix composite stream release race

- Add FPS control (1-60, default 20) to test preview modal next to LED count
- Server accepts fps query param, controls frame send interval
- Single Apply icon button (✓) applies both LED count and FPS
- FPS control stays visible for picture sources (LED count hidden)
- Fix composite sub-stream consumer ID collision: use unique instance ID
  to prevent old WebSocket release from killing new connection's streams

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

server/src/wled_controller/api/routes/color_strip_sources.py

@@ -682,6 +682,7 @@ async def test_color_strip_ws(
     source_id: str,
     token: str = Query(""),
     led_count: int = Query(100),
+    fps: int = Query(20),
 ):
     """WebSocket for real-time CSS source preview. Auth via ``?token=<api_key>``.
 
@@ -723,8 +724,12 @@ async def test_color_strip_ws(
     if hasattr(stream, "configure"):
         stream.configure(max(1, led_count))
 
+    # Clamp FPS to sane range
+    fps = max(1, min(60, fps))
+    _frame_interval = 1.0 / fps
+
     await websocket.accept()
-    logger.info(f"CSS test WebSocket connected for {source_id}")
+    logger.info(f"CSS test WebSocket connected for {source_id} (fps={fps})")
 
     try:
         from wled_controller.core.processing.composite_stream import CompositeColorStripStream
@@ -846,7 +851,7 @@ async def test_color_strip_ws(
                     except Exception as e:
                         logger.warning(f"JPEG frame preview error: {e}")
 
-            await asyncio.sleep(0.05)
+            await asyncio.sleep(_frame_interval)
     except WebSocketDisconnect:
         pass
     except Exception as e:

server/src/wled_controller/core/processing/composite_stream.py

@@ -30,7 +30,9 @@ class CompositeColorStripStream(ColorStripStream):
     """
 
     def __init__(self, source, css_manager, value_stream_manager=None):
+        import uuid as _uuid
         self._source_id: str = source.id
+        self._instance_id: str = _uuid.uuid4().hex[:8]  # unique per instance to avoid release races
         self._layers: List[dict] = list(source.layers)
         self._led_count: int = source.led_count
         self._auto_size: bool = source.led_count == 0
@@ -167,7 +169,7 @@ class CompositeColorStripStream(ColorStripStream):
             src_id = layer.get("source_id", "")
             if not src_id:
                 continue
-            consumer_id = f"{self._source_id}__layer_{i}"
+            consumer_id = f"{self._source_id}__{self._instance_id}__layer_{i}"
             try:
                 stream = self._css_manager.acquire(src_id, consumer_id)
                 if hasattr(stream, "configure") and self._led_count > 0:

server/src/wled_controller/static/css/modal.css

@@ -317,6 +317,7 @@
 
 .css-test-led-input {
     width: 70px;
+    flex: 0 0 70px;
     padding: 3px 6px;
     border: 1px solid var(--border-color, #333);
     border-radius: 4px;
@@ -327,8 +328,22 @@
 }
 
 .css-test-led-apply {
-    padding: 3px 10px;
+    padding: 2px 6px;
-    font-size: 0.8em;
+    font-size: 0.85em;
+    line-height: 1;
+}
+
+#css-test-led-group {
+    display: inline-flex;
+    align-items: center;
+    gap: 8px;
+}
+
+.css-test-separator {
+    width: 1px;
+    height: 18px;
+    background: var(--border-color, #333);
+    margin: 0 4px;
 }
 
 #test-css-source-modal .modal-content {

server/src/wled_controller/static/js/app.js

@@ -125,7 +125,7 @@ import {
     onNotificationFilterModeChange,
     notificationAddAppColor, notificationRemoveAppColor,
     testNotification,
-    testColorStrip, closeTestCssSourceModal, applyCssTestLedCount, fireCssTestNotification, fireCssTestNotificationLayer,
+    testColorStrip, closeTestCssSourceModal, applyCssTestSettings, fireCssTestNotification, fireCssTestNotificationLayer,
 } from './features/color-strips.js';
 
 // Layer 5: audio sources
@@ -405,7 +405,7 @@ Object.assign(window, {
     onNotificationFilterModeChange,
     notificationAddAppColor, notificationRemoveAppColor,
     testNotification,
-    testColorStrip, closeTestCssSourceModal, applyCssTestLedCount, fireCssTestNotification, fireCssTestNotificationLayer,
+    testColorStrip, closeTestCssSourceModal, applyCssTestSettings, fireCssTestNotification, fireCssTestNotificationLayer,
 
     // audio sources
     showAudioSourceModal,

server/src/wled_controller/static/js/features/color-strips.js

@@ -1886,6 +1886,7 @@ export async function stopCSSOverlay(cssId) {
 /* ── Test / Preview ───────────────────────────────────────────── */
 
 const _CSS_TEST_LED_KEY = 'css_test_led_count';
+const _CSS_TEST_FPS_KEY = 'css_test_fps';
 let _cssTestWs = null;
 let _cssTestRaf = null;
 let _cssTestLatestRgb = null;
@@ -1901,6 +1902,11 @@ function _getCssTestLedCount() {
     return (stored > 0 && stored <= 2000) ? stored : 100;
 }
 
+function _getCssTestFps() {
+    const stored = parseInt(localStorage.getItem(_CSS_TEST_FPS_KEY), 10);
+    return (stored >= 1 && stored <= 60) ? stored : 20;
+}
+
 export function testColorStrip(sourceId) {
     // Clean up any previous session fully
     if (_cssTestWs) { _cssTestWs.close(); _cssTestWs = null; }
@@ -1920,31 +1926,37 @@ export function testColorStrip(sourceId) {
     document.getElementById('css-test-strip-view').style.display = 'none';
     document.getElementById('css-test-rect-view').style.display = 'none';
     document.getElementById('css-test-layers-view').style.display = 'none';
-    document.getElementById('css-test-led-control').style.display = '';
+    document.getElementById('css-test-led-group').style.display = '';
     const layersContainer = document.getElementById('css-test-layers');
     if (layersContainer) layersContainer.innerHTML = '';
     document.getElementById('css-test-status').style.display = '';
     document.getElementById('css-test-status').textContent = t('color_strip.test.connecting');
 
-    // Restore LED count + Enter key handler
+    // Restore LED count + FPS + Enter key handlers
     const ledCount = _getCssTestLedCount();
     const ledInput = document.getElementById('css-test-led-input');
     ledInput.value = ledCount;
-    ledInput.onkeydown = (e) => { if (e.key === 'Enter') { e.preventDefault(); applyCssTestLedCount(); } };
+    ledInput.onkeydown = (e) => { if (e.key === 'Enter') { e.preventDefault(); applyCssTestSettings(); } };
 
-    _cssTestConnect(sourceId, ledCount);
+    const fpsVal = _getCssTestFps();
+    const fpsInput = document.getElementById('css-test-fps-input');
+    fpsInput.value = fpsVal;
+    fpsInput.onkeydown = (e) => { if (e.key === 'Enter') { e.preventDefault(); applyCssTestSettings(); } };
+
+    _cssTestConnect(sourceId, ledCount, fpsVal);
 }
 
-function _cssTestConnect(sourceId, ledCount) {
+function _cssTestConnect(sourceId, ledCount, fps) {
     // Close existing connection if any
     if (_cssTestWs) { _cssTestWs.close(); _cssTestWs = null; }
 
     // Bump generation so any late messages from old WS are ignored
     const gen = ++_cssTestGeneration;
 
+    if (!fps) fps = _getCssTestFps();
     const protocol = window.location.protocol === 'https:' ? 'wss:' : 'ws:';
     const apiKey = localStorage.getItem('wled_api_key') || '';
-    const wsUrl = `${protocol}//${window.location.host}/api/v1/color-strip-sources/${sourceId}/test/ws?token=${encodeURIComponent(apiKey)}&led_count=${ledCount}`;
+    const wsUrl = `${protocol}//${window.location.host}/api/v1/color-strip-sources/${sourceId}/test/ws?token=${encodeURIComponent(apiKey)}&led_count=${ledCount}&fps=${fps}`;
 
     _cssTestWs = new WebSocket(wsUrl);
     _cssTestWs.binaryType = 'arraybuffer';
@@ -1978,7 +1990,7 @@ function _cssTestConnect(sourceId, ledCount) {
             if (modalContent) modalContent.style.maxWidth = isPicture ? '900px' : '';
 
             // Hide LED count control for picture sources (LED count is fixed by calibration)
-            document.getElementById('css-test-led-control').style.display = isPicture ? 'none' : '';
+            document.getElementById('css-test-led-group').style.display = isPicture ? 'none' : '';
 
             // Show fire button for notification sources (direct only; composite has per-layer buttons)
             const isNotify = _cssTestMeta.source_type === 'notification';
@@ -2115,14 +2127,22 @@ function _cssTestUpdateBrightness(values) {
     }
 }
 
-export function applyCssTestLedCount() {
+export function applyCssTestSettings() {
-    const input = document.getElementById('css-test-led-input');
+    if (!_cssTestSourceId) return;
-    if (!input || !_cssTestSourceId) return;
+
-    let val = parseInt(input.value, 10);
+    const ledInput = document.getElementById('css-test-led-input');
-    if (isNaN(val) || val < 1) val = 1;
+    let leds = parseInt(ledInput?.value, 10);
-    if (val > 2000) val = 2000;
+    if (isNaN(leds) || leds < 1) leds = 1;
-    input.value = val;
+    if (leds > 2000) leds = 2000;
-    localStorage.setItem(_CSS_TEST_LED_KEY, String(val));
+    if (ledInput) ledInput.value = leds;
+    localStorage.setItem(_CSS_TEST_LED_KEY, String(leds));
+
+    const fpsInput = document.getElementById('css-test-fps-input');
+    let fps = parseInt(fpsInput?.value, 10);
+    if (isNaN(fps) || fps < 1) fps = 1;
+    if (fps > 60) fps = 60;
+    if (fpsInput) fpsInput.value = fps;
+    localStorage.setItem(_CSS_TEST_FPS_KEY, String(fps));
 
     // Clear frame data but keep views/layout intact to avoid size jump
     _cssTestLatestRgb = null;
@@ -2130,7 +2150,7 @@ export function applyCssTestLedCount() {
     _cssTestLayerData = null;
 
     // Reconnect (generation counter ignores stale frames from old WS)
-    _cssTestConnect(_cssTestSourceId, val);
+    _cssTestConnect(_cssTestSourceId, leds, fps);
 }
 
 function _cssTestRenderLoop() {

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

@@ -932,6 +932,7 @@
   "color_strip.test.connecting": "Connecting...",
   "color_strip.test.error": "Failed to connect to preview stream",
   "color_strip.test.led_count": "LEDs:",
+  "color_strip.test.fps": "FPS:",
   "color_strip.test.apply": "Apply",
   "color_strip.test.composite": "Composite",
   "color_strip.type.daylight": "Daylight Cycle",

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

@@ -932,6 +932,7 @@
   "color_strip.test.connecting": "Подключение...",
   "color_strip.test.error": "Не удалось подключиться к потоку предпросмотра",
   "color_strip.test.led_count": "Кол-во LED:",
+  "color_strip.test.fps": "FPS:",
   "color_strip.test.apply": "Применить",
   "color_strip.test.composite": "Композит",
   "color_strip.type.daylight": "Дневной цикл",

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

@@ -932,6 +932,7 @@
   "color_strip.test.connecting": "连接中...",
   "color_strip.test.error": "无法连接到预览流",
   "color_strip.test.led_count": "LED数量:",
+  "color_strip.test.fps": "FPS:",
   "color_strip.test.apply": "应用",
   "color_strip.test.composite": "合成",
   "color_strip.type.daylight": "日光循环",

server/src/wled_controller/templates/modals/test-css-source.html

@@ -42,11 +42,16 @@
                 <div id="css-test-layers" class="css-test-layers"></div>
             </div>
 
-            <!-- LED count control -->
+            <!-- LED count & FPS controls -->
-            <div class="css-test-led-control" id="css-test-led-control">
+            <div class="css-test-led-control">
+                <span id="css-test-led-group">
                     <label for="css-test-led-input" data-i18n="color_strip.test.led_count">LEDs:</label>
                     <input type="number" id="css-test-led-input" min="1" max="2000" step="1" value="100" class="css-test-led-input">
-                <button class="btn btn-sm btn-secondary css-test-led-apply" onclick="applyCssTestLedCount()" data-i18n="color_strip.test.apply">Apply</button>
+                    <span class="css-test-separator"></span>
+                </span>
+                <label for="css-test-fps-input" data-i18n="color_strip.test.fps">FPS:</label>
+                <input type="number" id="css-test-fps-input" min="1" max="60" step="1" value="20" class="css-test-led-input">
+                <button class="btn btn-icon btn-sm btn-secondary css-test-led-apply" onclick="applyCssTestSettings()" title="Apply" data-i18n-title="color_strip.test.apply">&#x2713;</button>
             </div>
 
             <div id="css-test-status" class="css-test-status" data-i18n="color_strip.test.connecting">Connecting...</div>