NEW275908
VP9 with transparency plays back incorrectly 
https://bugs.webkit.org/show_bug.cgi?id=275908
Summary VP9 with transparency plays back incorrectly
Jake Archibald
Reported 2024-06-26 10:30:54 PDT
https://static-misc-3.glitch.me/alpha-video-test/vp9-video.html Plays back slowly, and with a grey background rather than transparent. Compare to Chrome/Firefox for the correct output.
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Radar WebKit Bug Importer
Comment 1 2024-07-03 10:31:21 PDT
<rdar://problem/131062589>
istepancar
Comment 2 2026-05-13 06:55:35 PDT
Pull request: https://github.com/WebKit/WebKit/pull/64837
fenogr
Comment 3 2026-10-28 07:36:04 PDT
Problems have been detected with the playback of alfi during scrolling (when the video moves out of view). The bug occurs with a vertical video file measuring 774px x 1000px, while no issues are observed with a horizontal video file measuring 1640px x 920px.
istepancar
Comment 4 2026-10-29 10:07:19 PDT
(In reply to fenogr from comment #3) > Problems have been detected with the playback of alfi during scrolling (when > the video moves out of view). The bug occurs with a vertical video file > measuring 774px x 1000px, while no issues are observed with a horizontal > video file measuring 1640px x 920px. I couldn't reproduce it. Could you please share that vertical video? Thank you!
istepancar
Comment 5 2026-10-29 10:07:43 PDT
(In reply to fenogr from comment #3) > Problems have been detected with the playback of alfi during scrolling (when > the video moves out of view). The bug occurs with a vertical video file > measuring 774px x 1000px, while no issues are observed with a horizontal > video file measuring 1640px x 920px. I couldn't reproduce it. Could you please share that vertical video? Thank you!
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