There's no handling for decoding errors in MediaPlayerPrivateWebM and errors are just ignored which would make the content appear as not playing.
<rdar://problem/120570295>
Pull request: https://github.com/WebKit/WebKit/pull/22576
Committed 272969@main (ac3459ad6236): <https://commits.webkit.org/272969@main> Reviewed commits have been landed. Closing PR #22576 and removing active labels.