Bug 220226 - Audio elements block WebContent main thread, causing multi-second rendering delays scrolling a real webpage
Summary: Audio elements block WebContent main thread, causing multi-second rendering d...
Status: NEW
Alias: None
Product: WebKit
Classification: Unclassified
Component: Media (show other bugs)
Version: Safari 14
Hardware: Unspecified Unspecified
: P2 Normal
Assignee: Nobody
URL:
Keywords: InRadar
Depends on:
Blocks:
 
Reported: 2021-01-02 07:33 PST by Mish
Modified: 2021-01-02 11:59 PST (History)
7 users (show)

See Also:

Attachments
Attached is the CPU-usage when scrolling the page (45.71 KB, image/png)
2021-01-02 11:59 PST, Mish 		no flags Details
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Description Mish 2021-01-02 07:33:02 PST 
If there are many <audio> elements on the webpage, the webpage does not render correctly and causes lags
for example, please see: https://storage.googleapis.com/ddsp/index.html
Comment 1 Alexey Proskuryakov 2021-01-02 10:40:04 PST 
I can reproduce multi-second rendering delays scrolling this page on an Apple Silicon Mac.

WebContent main thread is blocked running -[AVPlayerItemTrack isEnabled] via WebCoreAVFMovieObserver.
Comment 2 Radar WebKit Bug Importer 2021-01-02 10:40:14 PST 
<rdar://problem/72770737>
Comment 3 Mish 2021-01-02 11:59:17 PST 
Created attachment 416897 [details]
Attached is the CPU-usage when scrolling the page

Attached is the CPU-usage when scrolling the page