Bug 217860

Summary:	5.1 audio received over WebRTC is downmixed to stereo
Product:	WebKit	Reporter:	Justin Uberti <juberti>
Component:	WebRTC	Assignee:	Nobody <webkit-unassigned>
Status:	NEW ---
Severity:	Normal	CC:	eric.carlson, webkit-bug-importer, youennf
Priority:	P2	Keywords:	InRadar
Version:	Safari Technology Preview
Hardware:	Mac
OS:	macOS 10.15

Description Justin Uberti 2020-10-16 18:23:18 PDT

When receiving 5.1 channel Opus content over WebRTC, all channels are received and decoded but downmixed to stereo, even when a 5.1-compatible sound card is connected. 
<audio/> tags, on the other hand, do render 5.1 content properly, e.g., https://www2.iis.fraunhofer.de/AAC/multichannel.html.

This suggests that somewhere along the line a mixer is not being initialized with the right number of channels. I looked through the playout path and didn't see anything obvious, but I didn't investigate closely.

Comment 1 Radar WebKit Bug Importer 2020-10-17 09:38:43 PDT

<rdar://problem/70408614>