Bug 208095 - Fast <video>.playbackRate incredibly jerky
Summary: Fast <video>.playbackRate incredibly jerky
Status: NEW
Alias: None
Product: WebKit
Classification: Unclassified
Component: Media (show other bugs)
Version: Safari 13
Hardware: iPhone / iPad iOS 13
: P2 Normal
Assignee: Nobody
URL:
Keywords: InRadar
Depends on:
Blocks:
 
Reported: 2020-02-22 14:07 PST by Jerry Jongerius
Modified: 2020-02-23 13:23 PST (History)
1 user (show)

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Description Jerry Jongerius 2020-02-22 14:07:26 PST 
1. Visit https://www.duckware.com/test/webkit/iosplayvideofails.html
2. Click on 'playbackRate=10' button, and then play video
3. Compare results on iPad vs any Windows computer

On iPad, the result is very 'jerky'.  On Windows, the result is incredibly smooth.  On the iPad, I can obtain very smooth results via other means, which means that setting playbackRate should also be able to.  Why can't it?
Comment 1 Radar WebKit Bug Importer 2020-02-22 14:52:55 PST 
<rdar://problem/59701053>
Comment 2 Jerry Jongerius 2020-02-23 13:23:28 PST 
A good example: Visit https://www.w3.org/2010/05/video/mediaevents.html, click on "Bunny movie", click on "play()", click on "playbackRate++" six times.

In Chrome/Windows it sure looks like video is being updated at the display 60 fps.  But on iPad, the video looks like it is being updated only a couple of times per second.