video Directory Reference

Directory dependency graph for video:

Detailed Description

Video (VIDCOMM)

The DAQ GUI's Video view shows every camera and the HiDes link live, records them, and feeds OBS. This folder is the gateway side: mediamtx.yml (MediaMTX's config) and agent.mjs (the video agent that keeps recordings). The DAQ backend's half is diablo_server/backend/src/video/, the page is diablo_server/frontend/app/video/.

cameras ──RTSP pull──┐                                  ┌─ WebRTC (UDP 8189) ─▶ Video view, any LAN browser
                     ├─▶ MediaMTX + video agent ────────┤
HiDes Viewer ─UDP────┘   (the gateway machine)          └─ RTSP (8554, user obs) ─▶ OBS
        ▲                     ▲
        │                     └── DAQ backend: stream list, WHEP proxy, Save/Record (API 8887, agent 8886)
   UT-130 receiver

Where it runs

	DAQ backend	Gateway (+ agent)	Recordings
Workspace	star-rfs	star-rfs, sensor-video (starts with the stack)	star-rfs:daq-server/video/recordings/
Desert	someone's laptop	the media Mac: scripts/media-laptop.sh	the media Mac

On the DAQ laptop in the desert: Video > Edit > Gateway = the media Mac's .local name (the script prints it) and the gateway password. That setting is per machine and never committed.

Sources

• Camera (RTSP): the gateway pulls it. Main URL, optional low-res URL (small tiles play it; the large slot and focus play main), username, password (write-only).
• HiDes link (UDP): HiDes Viewer's Send to UDP, MPEG-TS, to localhost:5600 on the gateway machine (or <gateway>.local:5600 from elsewhere). Ports 5600-5609, clear of the DAQ's own UDP. An existing HiDes Viewer install may still remember 127.0.0.1:5000: change it.

Camera audio never reaches the Video view (it asks for video only) or recordings (the agent drops it). OBS does get it: mute it there, or turn audio off on the cameras.

What a tile says

LIVE (green) while frames arrive, STALE (amber) when the picture has frozen, and otherwise NO SIGNAL with one code:

Code	Means
UNREACH	no answer from the camera's address (unplugged, wrong IP, other network)
REFUSED	the camera answered but nothing listens on that port
AUTH	username/password rejected, or the camera wants one and none is set
PATH	the camera has no stream at that URL path
NO DATA	nothing arriving on the HiDes UDP port
NET	no media path to this browser (off the stand network)
GW	the camera answers, but the gateway has no video from it
ERR	anything else

Each stream can also be set to Zoom to fill (Edit): its tiles fill the slot and crop what overhangs, for cameras whose shape wastes the slot. Off by default: letterboxing never crops.

Files and passwords

File	Tracked	What
config/video.json	yes	streams, labels, URLs, layout, disk guard (recording.refuseBelowGB 20, stopBelowGB 5)
config/video.secrets.json	no	camera credentials; this machine's gateway host and password
video/gateway.password	no	set with scripts/video-gateway.sh --set-password; lets a remote DAQ backend in
video/obs.password	no	set with --set-obs-password; read-only RTSP for OBS

Recording

• Streams marked include in recording are buffered continuously (10 s segments, 5 min).
• Save last 5 min keeps the buffer. Record keeps from the press until Stop.
• Output: video/recordings/<time>_save|record/<stream>.mp4, video only, no re-encode, and <stream>.json beside it: when each stretch of the file was filmed (the keyframe cut and any outage included), for the DAQ Run Viewer, with the gateway's clock offset from the DAQ's (the backend measures it over GET /clock at each press). One ffprobe per kept segment at Stop/Save; nothing while recording. The Recordings view (/recordings) lists them and opens a folder in the gateway machine's file manager (Finder; xdg-open on Linux) – useful when you are at that machine. The note after a save names gaps (gateway or camera down) and streams that were missing.

• The DAQ Run Viewer shows these clips above a run's plot, at their time (tools/postprocessing/webviewer, VIDEO_RECORDINGS_HOST_DIR). After a desert trip, copy the media Mac's recordings into that folder on star-rfs (names carry their time, so a second copy changes nothing):

  rsync -av --exclude '.*' <media-mac>.local:<Recordings>/ <VIDEO_RECORDINGS_HOST_DIR>/

  <Recordings> is the folder scripts/media-laptop.sh prints at start-up.

• The disk guard runs on the gateway machine: Record is refused below 20 GB free, and stops cleanly at 5 GB. A recording interrupted by a restart is finished when the gateway starts.

Storage: about 37.5 MB per Mbit/s per 5 minutes per stream. Four 1080p cameras at 4 Mbit/s: ~650 MB of buffer, ~7 GB per hour of recording. The Recording controls panel shows disk left at the current rate.

OBS

One Media Source per stream: Edit shows each URL (rtsp://<gateway>:8554/raw/<id>, user obs). For low latency: network buffering 0, hardware decoding on, RTSP over TCP. A VLC source needs its network caching lowered from 1000 ms to about 200.

Ports

Port	What	Open to the LAN
8189/udp	WebRTC media to browsers	yes
8554/tcp	RTSP (OBS, user obs)	yes
5600-5609/udp	pushed MPEG-TS (HiDes)	yes
8887/tcp	MediaMTX API (user daq)	only for a remote DAQ backend
8886/tcp	video agent (user daq)	only for a remote DAQ backend
8889/tcp	WHEP (the backend proxies it)	only for a remote DAQ backend

Testing

cd diablo_server/backend && npm test                 # unit tests (fakes)
cd diablo_server/backend && npm run test:video-gateway  # the real MediaMTX + ffmpeg + Chromium
cd diablo_server/frontend && npm test

Not yet checked on hardware: real cameras, the UT-130 end to end through the gateway, OBS, and latency (live-video's hides-latency can measure it). Do a bench check before the first desert trip.