Re: [mediacapture-main] Should we revisit and document getUserMedia() track order? (#1028)

There are four separate technical issues here.

1/ getUserMedia track order (what the title says) and *how it affects peerconnection*
* is *the same* for Chromium and Firefox
* sorted by random id in Safari. As pointed out above this caused some issues in the past. I do not think a webkit bug was filed, web developers moved on. 

2/ how does getTracks behave if a video track and a audio track are added to a GUM track and then used in a peerconnection
* There are difference in this case.
* How often developers do this is unknown
Since "more than a single audio and video track" is not well supported in other APIs like the HTMLMediaElement or MediaRecorder (which surprisingly does not throw on multiple video tracks) I do not think this is actually relevant.

3/ how does getTracks behave if an audio track from getUserMedia is added to a video track from getDisplayMedia  and then used in a peerconnection
* There are difference in this case.
* How often developers do this is unknown but since audio-only+screensharing is common 
I believe this use-case is common enough that we would have heard if the differences cause any issue.
My *guess* is that audio-screen is the more common order here since JS has already acquired your microphone when you start sharing.

4/ SDP
* https://jsfiddle.net/fippo/6t7pa0d3/1/ shows the ontrack order on the remote end matches the addition order on the receiving end.
* I could not find a WPT.

Of those four problems I have only seen evidence of breakage for (1, link above) and of course (4) is a headache.
I have not heard of any "web developer" asking for changes in (2) or (3) and my rolodex is quite extensive.

Speaking as a web developer please @youennf consider (1)

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Received on Thursday, 20 February 2025 04:10:42 UTC