createLocalTracks with video device with exact id, exact constraint is not maintained on re-enabling camera

[mdanilakis]

Describe the bug

const video = {
  deviceId: { exact: "deviceId" },
};

const audio = { ... };

const tracks = await createLocalTracks({ video, audio });

Constraining the deviceId with exact on Track creation.

Expectation: internally getUserMedia is called with exact the first time, and should be called again on restart (e.g. unmute of camera).

What happens: internally getUserMedia is called with exact the first time, but on unmute the exact constraint is removed resulting in selecting a different video stream (from a different device) on unmute (tested in Chrome).

Where I think the issue is: https://github.com/livekit/client-sdk-js/pull/773/files

Why is the browser returning a different stream given it actually returned it correctly the first time: I don't know (this is where the whole getUserMedia madness starts).

Reproduction

1. Create LocalTrack(s) using:

const video = {
  deviceId: { exact: "deviceId" },
};

const audio = { ... };

const tracks = await createLocalTracks({ video, audio });

2. Verify correct camera feed
3. Switch off camera e.g. localParticipat.setCameraEnabled(false)
4. Switch on camera
5. Camera feed is from a different device from the one specified in exact

Note: it happens under specific circumstances (hard to reproduce on some clients, reproducible with others - e.g. with a different set of devices).

Logs

No response

System Info

Mac OS, Chrome 130.0.6723.119, LiveKit Client 2.1.5

Severity

annoyance

Additional Information

No response