1560907 - MediaStreamTrack::GetConstraints() returns {mediaSource: "camera"} for all tracks where it should be empty

Status: RESOLVED FIXED

(Core :: WebRTC: Audio/Video, defect, P3)

Description

[Andreas Pehrson [:pehrsons]]

STR:

Create a track that doesn't have constraints: e.g., a received track from a peer connection, a track from a WebAudio MediaStreamAudioDestinationNode, a CanvasCaptureMediaStream track.
Log the result from calling getConstraints() on the track

Expected: {}

Actual: {mediaSource: "camera"}

Comment 1

[Jan-Ivar Bruaroey [:jib] (needinfo? me)]

This is why: https://searchfox.org/mozilla-central/rev/928742d3ea30e0eb4a8622d260041564d81a8468/dom/webidl/MediaStreamTrack.webidl#49

Long story, but it's a mutually exclusive constraint.

Comment 2

[Jan-Ivar Bruaroey [:jib] (needinfo? me)]

The model here violates constraints a bit.
Constraints traditionally all constrain on a single pool.
Except we allow default values, which then effectively makes it a switcher between different pools.
Basically this is only used in MediaManager, so we should remove the default, and insert it where it's still needed in MediaManager.

We can do that now if we care terribly, or we can wait for bug 1557174 to rip out mediaSource.

Comment 3

[Andreas Pehrson [:pehrsons]]

That sounds simple enough, especially given that there's no clear timeline for bug 1557174.

Comment 4

[Andreas Pehrson [:pehrsons]]

Attachment: Bug 1560907 - Remove default value for mediaSource constraint. r?jib

Comment 5

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/dc3e09fb750b
Remove default value for mediaSource constraint. r=jib,smaug

Comment 6

[Andrei Ciure[:aciure]]

https://hg.mozilla.org/mozilla-central/rev/dc3e09fb750b