alexei.dolgolyov
ef1f9eade2
Multi-axis lift to ship-quality after a full review:
Security
- ApiKeyManager: per-install random API key, persisted via SharedPreferences
with synchronous first-write; threaded into uvicorn via the
LEDGRAB_AUTH__API_KEYS env var; embedded in QR as a URL fragment (#k=)
so it never appears in HTTP requests or server logs; frontend reads
location.hash on first visit and strips it via history.replaceState
- Root.runAsRoot(argv: Array<String>) overload with POSIX shell-quoting to
eliminate the shell-injection footgun (= excluded from unquoted-safe set)
- UsbSerialBridge: ContextCompat.RECEIVER_NOT_EXPORTED + intent.package
check in the broadcast receiver for defence-in-depth across API levels
- Release builds refuse to silently fall back to debug keystore; require
ANDROID_KEYSTORE_* env vars or explicit
ANDROID_ALLOW_DEBUG_SIGNED_RELEASE=1
- Crash log retention capped at 10 entries
- Fatal-error stack trace hidden behind a toggle on the error screen
Performance
- ScreenCapture / RootScreenrecord reuse a single RGBA ByteArray per
pipeline instead of allocating per frame — eliminates ~15 MB/s GC churn
at 30 fps on low-end TV boxes
- Frame pacer switched from System.currentTimeMillis() + integer division
(~30.3 fps drift) to SystemClock.elapsedRealtimeNanos with a catch-up
accumulator
- ScreenCapture computes capture dimensions from source aspect ratio so
non-16:9 displays don't get squashed
- RootScreenrecord input pump backs off 5 ms when MediaCodec is starved,
ending a tight spin that burned a CPU core on decoder stalls
- QR cached by URL — onResume from background no longer rebuilds the
560×560 bitmap each time
- ApiKey commit() pre-warmed off Main on app startup
Compatibility
- compileSdk / targetSdk bumped to 35 (Play Store requirement)
- armeabi-v7a build path added to build script + conditionally included
in gradle splits when the matching wheel is present in android/wheels/
- Foreground service type declared as mediaProjection|specialUse with
PROPERTY_SPECIAL_USE_FGS_SUBTYPE rationale; promotion via
ServiceCompat.startForeground with the correct type per mode
- NetworkUtils picks Ethernet > Wi-Fi > VPN > cellular instead of just
activeNetwork — fixes wrong-URL on TV boxes with both Ethernet + Wi-Fi
- enableOnBackInvokedCallback=true for Android 15 predictive-back
- Splash screen API via androidx.core:core-splashscreen — hides Chaquopy
stdlib unpack delay on cold first launch
UI / UX
- All previously hardcoded English strings (root prompt, permission
denial, fatal-error screen, notification text) now localised across
en/ru/zh
- Monochrome notification icon (was a colored launcher → gray blob in
status bar)
- 320×180 TV banner (was the square launcher → squashed on Leanback row)
- ViewStub-based running panel (deferred inflation)
- ObjectAnimator pulse on the Running status dot for liveness feedback
- "Starting…" button state while root is being probed
- Autostart checkbox hidden entirely on unrooted devices
- "No network" status when getLocalIpAddress returns null
- QR fallback hint text
- Animator cancelled in onStop to avoid leaking view hierarchy
Lifecycle hardening (from review)
- RootScreenrecord: processLock serialises EOF respawn vs concurrent
stop() to prevent orphaned screenrecord processes
- CaptureService.restartRootPipeline: publish-before-start under
@Synchronized to close the orphan window during watchdog restarts
- ScreenCapture.MediaProjection.Callback.onStop just flips
running=false instead of calling stop() (which self-joined
captureThread and hung 500 ms)
- updateUI early-returns when lateinit not initialised (fatal-error path)
- Watchdog give-up bound fixed (>= instead of >, was allowing 4 attempts)
server/android_entry.py accepts an optional api_key, sets
LEDGRAB_AUTH__API_KEYS={"android":<key>} as JSON before any LedGrab
import, logs a clear error if pydantic-settings parsing doesn't land
the value back in config (defensive guard against future settings
behaviour drift).
server/static/js/app.ts: bootstrap reads #k= from location.hash,
persists to localStorage, then strips via history.replaceState.
Two independent code-review passes; 147 relevant server tests still
pass; TypeScript and ruff clean.
LED Grab
Ambient lighting system that captures screen content and drives LED strips in real time. Supports WLED, Adalight, AmbileD, and DDP devices with audio-reactive effects, pattern generation, and automated profile switching.
What It Does
The server captures pixels from a screen (or Android device via ADB), extracts border colors, applies post-processing filters, and streams the result to LED strips at up to 60 fps. A built-in web dashboard provides device management, calibration, live LED preview, and real-time metrics — no external UI required.
A Home Assistant integration exposes devices as entities for smart home automation.
Features
Screen Capture
- Multi-monitor support with per-target display selection
- 6 capture engine backends — MSS (cross-platform), DXCam, BetterCam, Windows Graphics Capture (Windows), Scrcpy (Android via ADB), Camera/Webcam (OpenCV)
- Configurable capture regions, FPS, and border width
- Capture templates for reusable configurations
LED Device Support
- WLED (HTTP/UDP) with mDNS auto-discovery
- Adalight (serial) — Arduino-compatible LED controllers
- AmbileD (serial)
- DDP (Distributed Display Protocol, UDP)
- OpenRGB — PC peripherals (keyboard, mouse, RAM, fans, LED strips)
- Serial port auto-detection and baud rate configuration
Color Processing
- Post-processing filter pipeline: brightness, gamma, saturation, color correction, auto-crop, frame interpolation, pixelation, flip
- Reusable post-processing templates
- Color strip sources: audio-reactive, pattern generator, composite layering, audio-to-color mapping
- Pattern templates with customizable effects
Audio Integration
- Multichannel audio capture from any system device (input or loopback)
- WASAPI engine on Windows, Sounddevice (PortAudio) engine on Linux/macOS
- Per-channel mono extraction
- Audio-reactive color strip sources driven by frequency analysis
Automation
- Profile engine with condition-based switching (time of day, active window, etc.)
- Dynamic brightness value sources (schedule-based, scene-aware)
- Key Colors (KC) targets with live WebSocket color streaming
Dashboard
- Web UI at
http://localhost:8080— no installation needed on the client side - Progressive Web App (PWA) — installable on phones and tablets with offline caching
- Responsive mobile layout with bottom tab navigation
- Device management with auto-discovery wizard
- Visual calibration editor with overlay preview
- Live LED strip preview via WebSocket
- Real-time FPS, latency, and uptime charts
- Localized in English, Russian, and Chinese
Home Assistant Integration
- HACS-compatible custom component
- Light, switch, sensor, and number entities per device
- Real-time metrics via data coordinator
- WebSocket-based live LED preview in HA
Requirements
- Python 3.11+ (or Docker)
- A supported LED device on the local network or connected via USB
- Windows, Linux, or macOS — all core features work cross-platform
Platform Notes
| Feature | Windows | Linux / macOS |
|---|---|---|
| Screen capture | DXCam, BetterCam, WGC, MSS | MSS |
| Webcam capture | OpenCV (DirectShow) | OpenCV (V4L2) |
| Audio capture | WASAPI, Sounddevice | Sounddevice (PulseAudio/PipeWire) |
| GPU monitoring | NVIDIA (pynvml) | NVIDIA (pynvml) |
| Android capture | Scrcpy (ADB) | Scrcpy (ADB) |
| Monitor names | Friendly names (WMI) | Generic ("Display 0") |
| Profile conditions | Process/window detection | Not yet implemented |
Quick Start
Docker (recommended)
git clone https://git.dolgolyov-family.by/alexei.dolgolyov/ledgrab.git
cd ledgrab/server
docker compose up -d
Manual
Requires Python 3.11+ and Node.js 18+.
git clone https://git.dolgolyov-family.by/alexei.dolgolyov/ledgrab.git
cd ledgrab/server
# Build the frontend bundle
npm ci && npm run build
# Create a virtual environment and install
python -m venv venv
source venv/bin/activate # Linux/Mac
# venv\Scripts\activate # Windows
pip install .
# Start the server
export PYTHONPATH=$(pwd)/src # Linux/Mac
# set PYTHONPATH=%CD%\src # Windows
uvicorn ledgrab.main:app --host 0.0.0.0 --port 8080
Open http://localhost:8080 to access the dashboard.
Important: The default API key is
development-key-change-in-production. Change it before exposing the server outside localhost. See INSTALLATION.md for details.
See INSTALLATION.md for the full installation guide, including configuration, Docker manual builds, and Home Assistant setup.
Demo Mode
Demo mode runs the server with virtual devices, sample data, and isolated storage — useful for exploring the UI without real hardware.
Set the LEDGRAB_DEMO environment variable to true, 1, or yes:
# Docker
docker compose run -e LEDGRAB_DEMO=true server
# Python
LEDGRAB_DEMO=true uvicorn ledgrab.main:app --host 0.0.0.0 --port 8081
# Windows (installed app)
set LEDGRAB_DEMO=true
LedGrab.bat
Demo mode uses port 8081, config file config/demo_config.yaml, and stores data in data/demo/ (separate from production data). It can run alongside the main server.
Architecture
ledgrab/
├── server/ # Python FastAPI backend
│ ├── src/ledgrab/
│ │ ├── main.py # Application entry point
│ │ ├── config.py # YAML + env var configuration
│ │ ├── api/
│ │ │ ├── routes/ # REST + WebSocket endpoints
│ │ │ └── schemas/ # Pydantic request/response models
│ │ ├── core/
│ │ │ ├── capture/ # Screen capture, calibration, pixel processing
│ │ │ ├── capture_engines/ # MSS, DXCam, BetterCam, WGC, Scrcpy, Camera backends
│ │ │ ├── devices/ # WLED, Adalight, AmbileD, DDP, OpenRGB clients
│ │ │ ├── audio/ # Audio capture engines
│ │ │ ├── filters/ # Post-processing filter pipeline
│ │ │ ├── processing/ # Stream orchestration and target processors
│ │ │ └── profiles/ # Condition-based profile automation
│ │ ├── storage/ # JSON-based persistence layer
│ │ ├── static/ # Web dashboard (vanilla JS, CSS, HTML)
│ │ │ ├── js/core/ # API client, state, i18n, modals, events
│ │ │ ├── js/features/ # Feature modules (devices, streams, targets, etc.)
│ │ │ ├── css/ # Stylesheets
│ │ │ └── locales/ # en.json, ru.json, zh.json
│ │ └── utils/ # Logging, monitor detection
│ ├── config/ # default_config.yaml
│ ├── tests/ # pytest suite
│ ├── Dockerfile
│ └── docker-compose.yml
├── docs/
│ ├── API.md # REST API reference
│ └── CALIBRATION.md # LED calibration guide
├── INSTALLATION.md
└── LICENSE # MIT
Configuration
Edit server/config/default_config.yaml or use environment variables with the LEDGRAB_ prefix:
server:
host: "0.0.0.0"
port: 8080
log_level: "INFO"
auth:
api_keys:
dev: "development-key-change-in-production"
storage:
devices_file: "data/devices.json"
templates_file: "data/capture_templates.json"
logging:
format: "json"
file: "logs/ledgrab.log"
max_size_mb: 100
Environment variable override example: LEDGRAB_SERVER__PORT=9090.
API
The server exposes a REST API (with Swagger docs at /docs) covering:
- Devices — CRUD, discovery, validation, state, metrics
- Capture Templates — Screen capture configurations
- Picture Sources — Screen capture stream definitions
- Picture Targets — LED target management, start/stop processing
- Post-Processing Templates — Filter pipeline configurations
- Color Strip Sources — Audio, pattern, composite, mapped sources
- Audio Sources — Multichannel and mono audio device configuration
- Pattern Templates — Effect pattern definitions
- Value Sources — Dynamic brightness/value providers
- Key Colors Targets — KC targets with WebSocket live color stream
- Profiles — Condition-based automation profiles
All endpoints require API key authentication via X-API-Key header or ?token= query parameter.
See docs/API.md for the full reference.
Calibration
The calibration system maps screen border pixels to physical LED positions. Configure layout direction, start position, and per-edge segments through the web dashboard or API.
See docs/CALIBRATION.md for a step-by-step guide.
Home Assistant
For Home Assistant integration, see the separate ledgrab-haos-integration repository.
Development
cd server
# Install with dev dependencies
pip install -e ".[dev]"
# Run tests
pytest
# Format and lint
black src/ tests/
ruff check src/ tests/
Optional extras:
pip install -e ".[perf]" # High-performance capture engines (Windows)
pip install -e ".[camera]" # Webcam capture via OpenCV
License
MIT — see LICENSE.