Bug 259273 – REGRESSION (Safari 16.5): Unexpected mute event on audio track

• Status: NEW
• Component: WebRTC

Created attachment 467060 [details]
Microphone icon paused in status bar.

Hi, we have a web application which has capabilities for audio-video conferencing using WebRTC and also ability to stream a video from cloud.
We are seeing a new issue with Safari v16.5. No issues seen with Safari v16.4.
Scenario:
1. Client calls getUserMedia and gets access to mic and camera tracks
2. Video Streaming from cloud starts, browser starts to render the video and playout the audio of the file.
3. Once the video streaming is paused, the onmute event on audio track is triggered.
From the status bar on the browser, it looks like microphone use has been paused too. Screenshot attached.
4. Once the video streaming is resumed, the onunmute event on audio track is triggered.

This behavior is seen on Safari v16.5, no issues were reported with earlier safari versions (eg v16.4)
This behavior is causing issues because we expect the track mute status to not change under these cases.
Can you please help me understand why this happens or point in the right direction to fix this, if it can be fixed from the client side.
From our investigation, we didn't find anything that has got do with the track when video streaming operations are performed.

Issue seen on:
Safari - Version 16.5 (18615.2.9.11.4) / Mac OS Version - 13.4 (22F66)
Intel based Mac - 2.6 GHz 6-Core Intel Core i7

Please let me know if you need more information:

[Radar WebKit Bug Importer]

<rdar://problem/112497748>

[youenn fablet]

Is there a way for us to reproduce this?

Is it basically calling getUserMedia, then playing a video (say HLS) will cause the microphone to become muted? Pausing te video will trigger the microphone to be unmuted?
What about the camera?

Hi Youenn,
I can check and let you know if I can give you some page to replicate this issue.
But we are able to reproduce this consistently, if you want us to capture any debug information or logs, please do tell, we can provide that.

It is basically, calling getUserMedia and then playing a video. Nothing happens when you are playing the video, but when you pause it we receive the muted event on the track. When we resume the video we receive the unmuted event.
This happens on both video and audio track some cases and in some cases it only happens on audio track.

[youenn fablet]

I tried https://jsfiddle.net/cgx06fwq/ and I am not able to reproduce on a recent macOS Sonoma build.
Can you try it?

If it reproduces the issue, can you try Safari Tech Preview?

Sure youenn, I will get the engineer who is able to repro this issue to try on this jsfiddle. Thanks!!

Created attachment 467129 [details]
sysdiagnose captured when the issue happened

Hi youenn,
The issue is not reproducible on the jsfiddle that you shared, but is consistently happening on our application.
Please find the sysdiagnose file that we captured when we reproduced the issue if it helps you debug this.
At 05:54:29.9510 (IST) - the audio track was muted by the browser.
Our browser console printed the below log.
`Local Audio track has been muted.`

Thanks. Please let me know if you need any info from our side for this.

Comment on attachment 467129 [details]
sysdiagnose captured when the issue happened

The timestamp of the issue 05:54:29.9510 PM (IST)

[youenn fablet]

I need to update the jsfiddle to try with both regular video streaming and MSE.

[youenn fablet]

I was not able to reproduce.
@vinayak, can you reproduce with the latest Safari Tech Preview? 
If so, can you either provide a repro case or send me ([e-mail]) a sysdiagnose with the time where the issue happens on STP (I added some more logging)?