Bug 219634

Summary: Garbled audio from WebRTC remote stream that fixes itself after random period of time.
Product: WebKit Reporter: Adam Szmyd <szmydadam>
Component: WebRTCAssignee: Nobody <webkit-unassigned>
Status: RESOLVED CONFIGURATION CHANGED    
Severity: Major CC: jrh, webkit-bug-importer, youennf
Priority: P2 Keywords: InRadar
Version: Safari 14   
Hardware: All   
OS: macOS 10.15   
Attachments:
Description Flags
output-audio.m4a and source-audio.wav files none

Description Adam Szmyd 2020-12-08 02:30:35 PST 
Created attachment 415623 [details]
output-audio.m4a and source-audio.wav files

For some reason, Safari 14 seems to garble audio that came from remote stream during WebRTC connection. I'm able to easily see this every time on my setup:

- Safari Version 14.0.1 (15610.2.11.51.10, 15610)
- macOS Catalina 10.15.7 (19H15) running on MacBook Pro (Retina, Mid 2012)

Steps to reproduce (I used Jitsi Meet platform but I've seen the same on few others):
1. Establish WebRTC connection. I'm entering some jitsi room (https://meet.jit.si/SafariGarbledAudioTest) from Chrome and Safari. "Second" browser that'll produce sound (Chrome in my case) seems to have nothing to do here as I've used several with different operating systems even and the looks like the issue is just on Safari side as a receiver.
2. Make some sound (talk) so that Safari browser will receive it.

Expected result: Safari plays out audio just fine
Actual result: Sound in Safari is garbled/distorted. It fixes itself within few seconds or longer (its random period of time but averagely after around 10-15s all works correctly).

Additional info:
1. I recorded the output of this bug and I'm attaching it as "output-audio.m4a". You can see there that in ~15s audio clears out itself. No action is made on any side and this just fixes itself after random amount of seconds
2. To keep things reproducable and more predictable, I generate source audio from pre-recorder wav file and run it like "google-chrome-stable --use-file-for-fake-audio-capture="source-audio.wav" --use-fake-device-for-media-stream" using chrome. I wanted to attach it also.
Comment 1 Adam Szmyd 2020-12-08 02:38:11 PST 
I'm also able to see it on Safari 14 on iOS 14.2 (Mozilla/5.0 (iPhone; CPU iPhone OS 14_2 like Mac OS X) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/14.0.1 Mobile/15E148 Safari/604.1)
Comment 2 youenn fablet 2020-12-08 02:45:23 PST 
This is probably fixed in the latest iOS 14.3 betas, as well as Safari Tech Preview.
I haven't heard of that issue in macOS Catalina 10.15.7.
Comment 3 Radar WebKit Bug Importer 2020-12-08 02:45:48 PST 
<rdar://problem/72085482>
Comment 4 Adam Szmyd 2020-12-08 03:00:50 PST 
I can confirm it seems to be fixed in Safari Tech Preview I've tested (Release 116 (Safari 14.1, WebKit 15611.1.5.3)).

@youenn fablet is there anything I can do currently to work around this until the fixes are rolled out?
Comment 5 Josh Heling 2020-12-15 08:24:52 PST 
@youenn FYI this is still happening on Safari Tech Preview on Big Sur. It is reproducible using Jitsi Meet, if that is helpful.
Comment 6 youenn fablet 2020-12-15 08:37:57 PST 
(In reply to Josh Heling from comment #5)
> @youenn FYI this is still happening on Safari Tech Preview on Big Sur. It is
> reproducible using Jitsi Meet, if that is helpful.

I just tried a few times Jitsi meet and I do not hear it in my configuration.
Do you reproduce the same robotic sound or is it no sound at all?
Are you doing anything specific, a regular 1-1 call?
Can you file a feedback with a sysdiagnose or privately send me the sysdiagnose (youenn@apple.com)?
Comment 7 youenn fablet 2020-12-18 06:02:31 PST 
Marked as configuration changed.
Please verify this is working in latest BigSur, STP or iOS releases.
Comment 8 Josh Heling 2020-12-18 11:07:48 PST 
(In reply to youenn fablet from comment #6)
> (In reply to Josh Heling from comment #5)
> > @youenn FYI this is still happening on Safari Tech Preview on Big Sur. It is
> > reproducible using Jitsi Meet, if that is helpful.
> 
> I just tried a few times Jitsi meet and I do not hear it in my configuration.
> Do you reproduce the same robotic sound or is it no sound at all?
> Are you doing anything specific, a regular 1-1 call?
> Can you file a feedback with a sysdiagnose or privately send me the
> sysdiagnose (youenn@apple.com)?

I was passing along a report from another user, thus the delay in getting back to you with the requested sysdiagnose. Fortunately, I just met with that user and, as of their latest update, they are no longer seeing the problem.