269042 2024-02-08 19:26:44 -0800 MediaSource in GPU must wait for MediaPlayer in ContentProcess to process a new track 2024-02-08 19:27:10 -0800 1 1 1 Unclassified WebKit Media WebKit Nightly Build Unspecified Unspecified NEW https://bugs.webkit.org/show_bug.cgi?id=265982 InRadar P2 Normal --- 264134 1 jean-yves.avenard jean-yves.avenard webkit-bug-importer oldest_to_newest 2012063 0 jean-yves.avenard 2024-02-08 19:26:44 -0800 When the SourceBufferPrivate parses a new init segment, it will create a new Track object for each discovered track. The operation of creating the track is done by the MediaPlayerPrivate. When the GPU Process is in use, the Track created is a RemoteAudioTrackProxy/RemoteVideoTrackProxy/RemoteTextTrackProxy and this is done by the RemoteMediaPlayerProxy Each RemoteTrackProxy constructor then send a message to the MediaPlayerPrivateRemote running in the content process to register the new track. This operation is done on the main thread. Following bug 265982; MSE now runs in a dedicated WorkQueue to avoid being bottlenecked by the main thread's usage. However, parsing the init segment by the SourceBufferPrivate in the GPU Process can't complete until the CP's MediaPlayerPrivateRemote has fully processed the new track. This means that if the main thread is busy, the GPUP's MSE is now waiting. We should find a way to remove this bottleneck 2012065 1 webkit-bug-importer 2024-02-08 19:27:10 -0800 <rdar://problem/122599459>