STR.

1. go to https://hichannel.hinet.net/radio/index.do (VPN needed, the website is only available in Taiwan)
2. wait for ad ended

Expect.
3. the radio starts successfully

Actual
4. the radio fails to start

This issue only happens on Windows.

This is the root cause, we should change the original time as well. The decoding failed here because of incorrect original time.

The start time of the last frame we sent to MFT decoder is 22034000, but the start time decoder returned to us is 22033999. As we want to adjust that frame to the last frame time, so we would modify the start time to 22034000. Then, when we were doing trimming, the end time of the trimmer window was larger than mOriginalTime + originalDuration (only larger 1), which causes returning an error.

In AudioData, we use mOriginalTime to store the original start time before trimming, which should keep sync to mTime if data hasn't been trimmed before. Otherwise, if they are not equal, it would cause a problem when handling trimming.

For example.
If audio data's time is X, original time is X-1 and duration is T. When MDSM performs seeking, it would use (X + T) as trimming window's end time. However, in AudioData::SetTrimWindow(), original time + duration (X - 1 + T) would be less than the trimming end time, which causes an error.

Alastor, what does the website look like? Does it look like it's using hls (downloading a manifest then .ts files), or dash maybe (a manifest, and then fragmented mp4) ? It would be nice to write a test for this.

I made a stupid mistake, the reason I could not reproduce the issue on the file I captured was because I didn't play it via MSE API, I simply played it in a normal playback path. Now you should be able to see the error when opening this page on Windows10.

Will add test and ask for a review again, thanks!

Depends on D100825

https://hg.mozilla.org/mozilla-central/rev/30501df4232b
https://hg.mozilla.org/mozilla-central/rev/ccdcd06ee7d9

Reproduced on Firefox Nightly 86.0a1 (20201223092736) on Windows 10x64.
Verified fixed on Firefox beta 86.0b4 (20210131185630) on Windows 10x64.