feat: Phone video streaming bridge (Issue #585)
Phone side — phone/video_bridge.py:
- MJPEG streaming server for Android/Termux phone camera
- Dual camera backends: OpenCV VideoCapture (V4L2) with automatic
fallback to termux-camera-photo for unmodified Android
- WebSocket server (ws://0.0.0.0:8765) — binary JPEG frames + JSON
info/error control messages; supports multiple concurrent clients
- HTTP server (http://0.0.0.0:8766):
/stream — multipart/x-mixed-replace MJPEG
/snapshot — single JPEG
/health — JSON stats (frame count, dropped, resolution, fps)
- Thread-safe single-slot FrameBuffer; CaptureThread rate-limited with
wall-clock accounting for capture latency
- Flags: --ws-port, --http-port, --width, --height, --fps, --quality,
--device, --camera-id, --no-http, --debug
Jetson side — saltybot_phone/phone_camera_node.py:
- ROS2 node: receives JPEG frames, publishes:
/saltybot/phone/camera sensor_msgs/Image (bgr8)
/saltybot/phone/camera/compressed sensor_msgs/CompressedImage
/saltybot/phone/camera/info std_msgs/String (stream metadata)
- WebSocket client (primary); HTTP MJPEG polling fallback on WS failure
- Auto-reconnect loop (default 3 s) for both transports
- Latency warning when frame age > latency_warn_ms (default 200 ms)
- 10 s diagnostics log: received/published counts + last frame age
- Registered as phone_camera_node console script in setup.py
- Added to phone_bringup.py launch with phone_host / phone_cam_enabled args
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
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