Bug 220226

Summary:

Audio elements block WebContent main thread, causing multi-second rendering delays scrolling a real webpage

Product:

WebKit

Reporter:

Mish <mish>

Component:

Media

Assignee:

Nobody <webkit-unassigned>

Status:

NEW ---

Severity:

Normal

CC:

cdumez, eric.carlson, jer.noble, peng.liu6, simon.fraser, webkit-bug-importer, zalan

Priority:

Keywords:

InRadar

Version:

Safari 14

Hardware:

Unspecified

OS:

Unspecified

Attachments:

Description	Flags
Attached is the CPU-usage when scrolling the page	none

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