On Windows, muting outgoing streams causes choppy/delayed playback of incoming streams




WebRTC: Audio/Video
5 years ago
3 years ago


(Reporter: standard8, Unassigned)


Windows 7

Firefox Tracking Flags

(Not tracked)



1) Set up a webrtc call between a Mac book and a windows box. For this test I'm using the same nightly version (2013-09-08) on a local Wifi network.

2) On one end of the call, mute the outgoing streams, we're doing:

var streams = pc.getLocalStreams();
streams.forEach(function(stream) {
 if (media === 'audio')
   stream.getAudioTracks().enabled = !mute;


- Doing the Mute at the Mac end, correctly mutes the outgoing audio, and incoming audio sounds the same.

- Doing the Mute at the Windows end, correctly mutes the outgoing audio. However, the incoming audio is choppy and incomprehensible, if it is heard at all.

On Windows there is possibly audio lag after the mute is disabled as well.
Note I was testing this using https://talkilla.mozillalabs.com as https://apprtc.appspot.com doesn't yet have support for muting Firefox tracks.
Blocks: 859886
Mark - can you retry with pc_test.html?  You can mute local audio (for one direction) with a checkbox, and the other side should be either normal audio or 'fake' audio (which is now a 1khz sinewave at -20db).  Don't forget to unmute the appropriate video element to hear.  You can also tweak the example if needed.   If anything, that should be a tougher test since we're encoding and decoding two sets of audio and video, not just one

I tried this on nightly windows this morning and it was exactly the same (good) whether one direction was muted or unmuted.
Flags: needinfo?(mbanner)
I've been trying, and I think I could reproduce it. However, windows is being highly uncooperative in letting me select headsets, and generally giving me sounds, which makes it difficult to be sure. I'll try again before the weekend.
Mark -- Are you still seeing this problem?  Do you have more info for us?  Thanks.
I had actually forgotten this, and when I remembered last week, there was another audio bug which meant I couldn't test. I'll try and remember to get to this on Monday.
Depends on: 933198
Ok, I've just reproduced this with Firefox 25 at both ends, linking Mac to Windows.

I've tried two different windows machines. One of them, an Acer Aspire 5542G worked fine, the other a Lenovo W520 gave choppy audio when I muted the outgoing stream.
No longer depends on: 933198
Flags: needinfo?(mbanner)
roc: any reason you can think why muting would cause choppy audio?  Perhaps it has to do with the "bypass" of MSG on direct GUM->PC streams; we have to apply the mute in two places in that case I think.  Not sure why windows would affect it.
Flags: needinfo?(roc)
No idea.
Flags: needinfo?(roc)
Mark - does this still happen? A lot of this code has changed and I believe this is no longer happening. Can you repro?
backlog: --- → webRTC+
Rank: 21
Flags: needinfo?(standard8)
Priority: -- → P2
I've just been trying it again, and I haven't been able to reproduce. Hence going to mark this as WFM.
Last Resolved: 3 years ago
Flags: needinfo?(standard8)
Resolution: --- → WORKSFORME
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