Bug 255452 – [MSE][GStreamer] Avoid unneeded timechanged notifications

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

[Enrique Ocaña]

The YouTube MSE Conformance Tests 2021[1][2] added a check to ensure that the initial warm up time of the player is less than 500 ms in accuracy tests (). While these tests pass on a fast desktop computer, they fail on a lower end device (eg: Raspberry Pi 3). This is because there's a first timeupdate event triggered as soon as the appended init segment is processed, but the processing time of the next appended data segment takes too much time, so when playback actually starts, the next timeupdate event comes later than 500ms from the first one, causing the test to fail on slow platforms.

Since the default time of the video element should be 0 from the begining and the time reported by that initial timeupdate is actually 0 (no change), that initial timeupdate event is redundant (and wasn't happening before the WebKitMediaSrc rework[3]).

[1] https://ytlr-cert.appspot.com/2021/main.html?tests=35,36,37,38&command=run
[2] https://ytlr-cert.appspot.com/2021/media/conformanceTest.js, line 886 (best displayed as https://pastebin.com/fPx1EW22)
[3] https://github.com/WebKit/WebKit/commit/9382c6ef1a5b64d1701c691c63fe84de22cf932b

[Enrique Ocaña]

Pull request: https://github.com/WebKit/WebKit/pull/12741

[EWS]

Committed 263019@main (c6dd1fbfea75): <https://commits.webkit.org/263019@main>

Reviewed commits have been landed. Closing PR #12741 and removing active labels.

[Radar WebKit Bug Importer]

<rdar://problem/108127936>