Bug 220226

Summary: Audio elements block WebContent main thread, causing multi-second rendering delays scrolling a real webpage
Product: WebKit Reporter: Mish <mish>
Component: MediaAssignee: Nobody <webkit-unassigned>
Status: NEW    
Severity: Normal CC: cdumez, eric.carlson, jer.noble, peng.liu6, simon.fraser, webkit-bug-importer, zalan
Priority: P2 Keywords: InRadar
Version: Safari 14   
Hardware: Unspecified   
OS: Unspecified   
Attachments:
Description Flags
Attached is the CPU-usage when scrolling the page none

Mish
Reported 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
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
View All Add attachment proposed patch, testcase, etc.
Alexey Proskuryakov
Comment 1 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.
Radar WebKit Bug Importer
Comment 2 2021-01-02 10:40:14 PST
<rdar://problem/72770737>
Mish
Comment 3 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
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