Playback freezes at end of video in Edge/IE11

[forbesjo]

Have you read the FAQ and checked for duplicate issues:
Yes

What version of Shaka Player are you using:
2.1.4

Can you reproduce the issue with our latest release version:
Yes

Can you reproduce the issue with the latest code from master:
Yes

Are you using the demo app or your own custom app:
Custom

If custom app, can you reproduce the issue using our demo app:
Yes

What browser and OS are you using:
IE11 and Edge 38.14393.1066.0, Windows 10

What are the manifest and license server URIs:
http://dash.edgesuite.net/akamai/bbb_30fps/bbb_30fps.mpd (this issue does not happen with other test content)

(you can send the URIs to shaka-player-issues@google.com instead, but please use GitHub and the template for the rest)

What did you do?
Seek near the end of the video and let the video finish.

What did you expect to happen?
Playback to end and set the player in an ended state

What actually happened?
Playback stops at 633.9008751. Duration is 634.5666666.
End of the video buffer is 634.5666666, end of audio is 634.3547499.

[forbesjo]

Note that this source has never played through to the end in any version of the Shaka Player. It does in dash.js and native Edge playback.

[TheModMaker]

This is a platform bug. We call MediaSource.endOfStream to indicate that no more content is coming. The browser should update the duration to match the already buffered content, but sometimes it doesn't. In this case, IE/Edge is stopping, waiting for more content.

You may want to file a bug on Edge to fix it. We will look into trying to work around it.

[joeyparrish]

IE and Edge are correctly truncating the duration to the largest of the buffered ranges for audio & video. It's not obviously a platform bug as we previously thought.

[joeyparrish]

If we comment out setBuffering() in Playhead, the problem disappears. This is called by PlayheadObserver, which calculates when we should or shouldn't be buffering. So PlayheadObserver is sending Player into a buffering state on IE & Edge, when it shouldn't.

In this case, audio SourceBuffer ends at 634.35, video ends at 634.56, and duration is 634.56 (on all browsers). On Chrome, video.buffered is (surprisingly) the larger of the two, while on IE it's the smaller of the two SourceBuffers. This calculation:

  var atEnd = (bufferEnd >= duration) || this.video_.ended;

is therefore true on Chrome and false on IE.

[joeyparrish]

In PlayheadObserver, the local value duration is the video duration minus a fudge factor of 0.1 seconds (shaka.media.PlayheadObserver.FUDGE_FACTOR_), but the actual discrepancy for this content is 0.21 seconds.

The real source of truth is mediaSource.readyState, which is 'ended'. Ideally, we would use this instead of comparing buffered ranges to the duration.

[joeyparrish]

Cherry-picked for v2.1.7.