mikkeli
d438b516e5
Camera-agnostic (--camera auto finds any V4L2 capture device and finds it again after a replug; non-MJPEG cameras are encoded), says when the camera is unavailable, paced per decision 28. Python, standard library only. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01DDwfd6Ki8UfG4hK6W5YpJz
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Vision guidelines
1. Camera-agnostic
- Any V4L2 capture device works. Never hard-code a node such as
/dev/video0: numbering follows enumeration order. Take a/dev/v4l/by-id/path, or find the camera at runtime (--camera auto). - Use what the camera offers. MJPEG passes through untouched; anything else is encoded here. A requested size or rate the camera lacks falls back to its own default rather than failing.
- UVC control names differ between cameras and kernels. Look them up on the device; reply that a control is missing rather than guessing.
2. One process owns the camera
- V4L2 capture is single-reader. This service opens the device; recording and inference take frames from it, never from the device.
- UVC controls reset when the camera re-enumerates. Set them on open, not once.
3. The tablet link is the constraint
- Every socket to a display is paced (
SO_MAX_PACING_RATE, project-yukart decision 28). Unpaced bursts stall the USB link for seconds. - Latest frame wins. A slow client skips frames; it never gets a queue of old ones.
- Say when there is no camera. A client must be able to tell "unavailable" from "slow".
4. Python, on purpose
- Python 3.10 (the Orin's), standard library only; GStreamer and v4l-utils come from the host. The exception to Rust for Orin services is decision 29: camera pipelines and inference live in the Python ecosystem.
- No pip installs on the car Orin until there is a reason; then a venv under
~/infra/svc-vision/, never the system Python.