RobOS Camera Watch

RobOS Camera Watch (packages/camera-watch) watches the IP cameras on your home or office network. It uses two open-source pieces: the onvif package (MIT) for everything ONVIF, and ffmpeg for video. Nothing goes through a vendor cloud.

Start with the illustrated Camera Watch setup and permissions guide, including photographs of camera sharing and a live view on a second RobOS computer. Read the camera network story for how scoped invites and per-camera access work together.

What you need

• ffmpeg on the machine (sudo apt install ffmpeg on Ubuntu). Settings shows whether Camera Watch can find it, and you can enter a full path.
• Cameras on the same network. ONVIF cameras can be found automatically. Many brands ship with ONVIF turned off, so turn it on in the camera’s own settings first.

Adding cameras

• Find cameras sends a WS-Discovery probe (UDP multicast 239.255.255.250:3702) and lists the ONVIF cameras that answer, with their names and models. Pick one, enter its user name and password, and Camera Watch asks the camera for its stream address, snapshot address, profiles and PTZ support.
• Add camera → Stream address takes any address ffmpeg can open: rtsp://, rtsps:// or an MJPEG http:// stream. Use this for cameras without ONVIF.
• Add camera → Webcam on this computer lists the USB webcams and capture cards ffmpeg can open (DirectShow on Windows, V4L2 on Linux, AVFoundation on macOS) and lets you pick a picture size. A webcam can usually be open in one program at a time, so close video calls first. Webcam clips are made from the live view’s frames, so they have its frame rate and size (Settings → Live view). New webcams detect motion but don’t record it until you turn on Record when motion starts, since a desk webcam usually points at you.
• Test connection grabs one frame and shows it, so a wrong address or password shows up before you save. For ONVIF cameras you can pick the stream profile here (for example the camera’s lower-resolution sub stream, which uses less CPU).

Camera passwords are saved in ~/.config/robos/camera-watch/cameras.json (readable only by you) and are never sent to the window or included in Config Sync backups.

Live view

The Live tab shows every camera that is on, in a 1, 2×2, 3×3 or 4×4 grid. Each tile shows the camera’s state, frames per second, a motion meter and REC when it is recording. Click a tile to open it large with its controls; double-click for full screen.

One ffmpeg process per camera reads the stream and writes JPEG frames for the live view and tiny grey frames for motion detection. A camera that drops off the network is retried with a growing delay, and the live view picks up again when it comes back.

Motion detection

Motion is detected on your computer by comparing each small grey frame with a slowly-updated background picture:

• Sensitivity sets how much a pixel must change to count.
• Area that must change sets how much of the picture (or of the zones) must change, and it must happen in two frames in a row.
• Draw zones limits detection to rectangles you drag on the picture, for example the path to the door but not the street.
• A change over most of the picture at once (lights switching on, the camera flipping to night mode) resets the background instead of counting as motion.
• ONVIF cameras can also send their own motion alarms (Also use the camera’s own motion alarms).

Each motion event is listed under Motion events with a picture from the moment it started, how long it lasted and the clip, and a desktop notification appears when the window is not in front.

Recording

With Record when motion starts on, a clip starts when motion starts and stops a set number of seconds after it ends. Record in the camera view records by hand, and Snapshot saves a still. RTSP cameras are recorded by copying the camera’s own H.264 or H.265 stream into an MP4, so recording uses little CPU; MJPEG cameras are encoded to H.264.

Recordings go to ~/Videos/Camera Watch/<camera>/<date>/ by default. The Recordings tab plays clips and shows stills, and Camera Watch deletes its own clips and stills older than the number of days set in Settings (14 by default, 0 keeps everything). Other files in that folder are left alone.

Sharing cameras with another RobOS

You can let someone on another RobOS machine watch some of your cameras, on your network or on theirs, through the RobOS private network (App Mesh).

1. Share → tick the cameras → say who it is for → Create invite. If they are on a different network, tick They are on a different network. That opens an encrypted relay through localhost.run (needs ssh), so the invite works from anywhere. The relay only forwards the encrypted mutual-TLS connection; it cannot see the video.
2. Send them the robos-cam://… invite privately. Anyone who has it can watch those cameras until you take it back.
3. They choose Add camera → Shared with me, paste it and save. Their Camera Watch joins your private network and the cameras show up in their grid with live view, motion detection and (if they turn it on) recording.

What the invite allows:

• It is a scoped invite: their machine and yours pin each other’s certificates with access to Camera Watch’s share service (camera-watch-share, 127.0.0.1:19221) only, in both directions. It does not reach your other RobOS apps, their debug ports or anything else on your machine, and a full robos-net:// network invite is not needed.
• Each shared camera has its own secret, so they see only the cameras in their invite.
• Share → Who can watch lists each invite, who joined with it and how many people are watching now. Revoke removes those machines from your private network and closes the streams they have open right away. Stop sharing on a camera changes its secret, so every invite loses that camera.
• Shared video is the same JPEG frames your own live view uses, so sharing adds no encoding work, and it never goes through a cloud service.

Pan, tilt and zoom

For ONVIF cameras with PTZ, hold an arrow or zoom button to move and release to stop. Moves time out on the camera after two seconds in case the stop request is lost. Presets saved on the camera appear in Go to preset.

Limits

• Browsers inside Electron play H.264 clips; H.265 clips may need an external player (Show in folder).
• There is no pre-motion buffer yet: a clip starts at the moment motion is detected.
• Two-way audio, camera settings and NVR playback (ONVIF Profile G) are not supported.