Bug 271685 – [MSE] media element will error appending the same media segment twice

• Status: RESOLVED
• Resolution: FIXED
• Component: Media

[Jean-Yves Avenard [:jya]]

Consider the following code:

```
    run('sourceBuffer.appendBuffer(loader.mediaSegment(0))');
    await waitFor(sourceBuffer, 'update');
    run('sourceBuffer.appendBuffer(loader.mediaSegment(1))');
    await waitFor(sourceBuffer, 'update');
    run('sourceBuffer.appendBuffer(loader.mediaSegment(1))');
    await waitFor(sourceBuffer, 'update');
```

Appending mediaSegment(1) twice will cause the media element to throw an error.

The cause is the SourceBufferParserAVFObjC's `AVStreamDataParser` to return `AVErrorFailedToParse`

[Radar WebKit Bug Importer]

<rdar://problem/125386530>

[Jean-Yves Avenard [:jya]]

test page:
https://jyavenard.github.io/htmltests/tests/mse_mp4/271685/

loads in firefox.

[Jean-Yves Avenard [:jya]]

Pull request: https://github.com/WebKit/WebKit/pull/26508

[EWS]

Committed 276821@main (7d2a7b505c37): <https://commits.webkit.org/276821@main>

Reviewed commits have been landed. Closing PR #26508 and removing active labels.