Bug 235030 - There is a big delay of video media stream if we share screen by getDisplayMedia in Safari from different MacOS desktops
Summary: There is a big delay of video media stream if we share screen by getDisplayMe...
Status: NEW
Alias: None
Product: WebKit
Classification: Unclassified
Component: WebRTC (show other bugs)
Version: Safari 15
Hardware: Mac (Intel) Unspecified
: P1 Critical
Assignee: Nobody
URL:
Keywords: InRadar
Depends on:
Blocks:
 
Reported: 2022-01-10 06:27 PST by walter
Modified: 2022-01-17 18:38 PST (History)
3 users (show)

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Description walter 2022-01-10 06:27:20 PST 
If we share screen by API "getDisplayMedia" in Safari on different MacOS desktops, there will be a big delay in the shared video media streaming.
In other words, If we share screen in Safari in same desktop, that’s ok.   

The problem is found on Safari15, MacOS 11.x/12.x with Intel CPU. 


# Steps:

1. Alice join an online meeting by Safari
2. Bob also join the online meeting by other browsers, such as Chrome, Firefox or Safari.
3. Alice start to share her screen, auto play a PPT or video clip, such as https://www.youtube.com/watch?v=b96TnabpVyo in full screen or in another desktop



# Expect Result:

Bob should see shared screen video normally.

# Actual Result:

After a while, Bob see shared screen video freeze frequently, sometimes, freeze time exceeds 60 seconds.

I wrote an example to duplicate the issue: https://github.com/walterfan/webrtc_remote_sharing
Comment 1 Radar WebKit Bug Importer 2022-01-10 07:15:11 PST 
<rdar://problem/87339054>
Comment 2 youenn fablet 2022-01-16 23:03:11 PST 
I tried the repro case, but I did not reproduce the freeze.
I am unclear whether freeze is happening on generation side (getDisplayMedia) or in the transmission chain.
Can you send me privately a sysdiagnose (youenn@apple.com) if you can reproduce on most recent MacOS version, with the timing of the freezes?
Comment 3 walter 2022-01-17 18:38:20 PST 
Sorry for the confusion.  My local video file is large, so I give a youtube url. 
You need to download the video file and playback it in local in full screen or different desktop.

I can reproduce the issue 100%

Please let me know if you need any recording or sysdiagnose