RESOLVED FIXED302585
CMSampleBuffer serialiser doesn't handle when kCMFormatDescriptionExtension_SampleDescriptionExtensionAtoms contains more than one key 
https://bugs.webkit.org/show_bug.cgi?id=302585
Summary CMSampleBuffer serialiser doesn't handle when kCMFormatDescriptionExtension_S...
Jean-Yves Avenard [:jya]
Reported 2025-11-15 23:00:03 PST
When serialising a CMSampleBuffer to be transferred over IPC we first convert it to a MediaSampleBlock and its TrackInfo. The file loaded by the test `LayoutTests/media/media-source/media-managedmse-webvtt-track.html ` causes a decoding error when MediaSourceUseRemoteAudioVideoRenderer is enabled. The reason is that the file content/bip-bop-webvtt-frag.mp4's `avc1` box contains two keys: that standard `avcC` and a `btrt` one. The code to convert the CMFormatDescriptionRef to a VideoInfo createVideoInfoFromFormatDescription assumes that the required data to decode the video when two keys are present is the first one. But that's not always the case.
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Radar WebKit Bug Importer
Comment 1 2025-11-15 23:00:11 PST
<rdar://problem/164817308>
Jean-Yves Avenard [:jya]
Comment 2 2025-11-15 23:17:07 PST
Pull request: https://github.com/WebKit/WebKit/pull/54000
EWS
Comment 3 2025-11-17 18:29:27 PST
Committed 303154@main (05d2e2c1d540): <https://commits.webkit.org/303154@main> Reviewed commits have been landed. Closing PR #54000 and removing active labels.
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