new TrackSelection not updated in HlsChunkSource

[stevemayhew]

Issue description

When playing back adaptive HLS content if you change the playback speed the AdaptiveTrackSelection should level down to a lower bitrate track to avoid stalls, it does not because the playbackSpeed update is missed since the HlsChunkSource that calls this method references a stale TrackSelection.

The code that handles this is:

  @SuppressWarnings("unused")
  protected boolean canSelectFormat(
      Format format, int trackBitrate, float playbackSpeed, long effectiveBitrate) {
    return Math.round(trackBitrate * playbackSpeed) <= effectiveBitrate;
  }

Reproduction steps

Playback using any HLS content (I used the Mango Open Source video: https://mango.blender.org, I'll email an S3 bucket with an HLS version of this). Then:

1. Disable the audio track
2. Print or observer with a debugger the TrackSelection object reference in HlsChunkSource, it should change to match that in MediaPeriodHolder

Triage

This is easy to reproduce by just disabling the audio track. This forces a invalidate (TrackSelector.invalidate() called). The invalidate creates a new AdaptiveTrackSelection object, via TrackSelection.Factory.createTrackSelection()

The updated TrackSelection instance is stored in the MediaPeriodHolder but not updated in the HlsChunkSource. This is because of logic to avoid re-creating the SampleStream (a good thing) in HlsSampleStreamWrapper

Link to test content

Mango Open Source - Tears of Steel (I'll send a link)

A full bug report captured from the device

I'll send it, probably useless though, the issue is a logic issue not platform specific.

Version of ExoPlayer being used

dev-v2-r2.10.3 - 1275217

Device(s) and version(s) of Android being used

Evolution IPA-1104HDH-01. SDK 26

[tonihei]

Thanks for reporting. It looks this bug also affects other streaming types where we save a reference to the TrackSelection (e.g. DASH).

[stevemayhew]

You're more than welcome! Here's a proposed fix that is working for me locally: stevemayhew@ddfaa97

I am working from dev-v2-r2.10.3 so it will not directly merge with a pull.

I looked to write a test case, but that would entail building out test cases for the whole of HlsSampleStreamWrapper. We can talk about that project later if it's a worthy undertaking (lots of big methods would need to be split up to make the logic more testable, a bigger job then I would attempt with my experience current experience with the class).

If this is good, I'll move the change to base off dev-v2 and submit it as a pull.

[tonihei]

Thanks for the proposal. I re-implemented this in a slightly different way to move the update further down where we keep the streams.

[stevemayhew]

Cool, thanks. I’ll look for the change and test it.

…

On Mon, Aug 5, 2019 at 5:55 AM tonihei ***@***.***> wrote: Thanks for the proposal. I re-implemented this in a slightly different way to move the update further down where we keep the streams. — You are receiving this because you authored the thread. Reply to this email directly, view it on GitHub <#6256?email_source=notifications&email_token=AADBF6BJG2N2K7BRVYRMJ6DQDAPNVA5CNFSM4IIW4V7KYY3PNVWWK3TUL52HS4DFVREXG43VMVBW63LNMVXHJKTDN5WW2ZLOORPWSZGOD3RXFFQ#issuecomment-518222486>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AADBF6F55AODWWI4POUSFILQDAPNVANCNFSM4IIW4V7A> .

[ojw28]

Fix merged into dev-v2 and dev-v2-r2.10.4. If you could give it a quick test, that would be great.

[stevemayhew]

I’ll do it tomorrow, planning to move our branch forward from 2.10.3 anyway. The iFrame playlist parsing is ready to push a branch too, our CI is in the queue

…

On Mon, Aug 5, 2019 at 12:37 PM Oliver Woodman ***@***.***> wrote: Fix merged into dev-v2 and dev-v2-r2.10.4. If you could give it a quick test, that would be great. — You are receiving this because you authored the thread. Reply to this email directly, view it on GitHub <#6256?email_source=notifications&email_token=AADBF6GAK5WDOYIWJULL273QDB6QFA5CNFSM4IIW4V7KYY3PNVWWK3TUL52HS4DFVREXG43VMVBW63LNMVXHJKTDN5WW2ZLOORPWSZGOD3S3E7A#issuecomment-518369916>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AADBF6CSYYVWLJS2YP55BUTQDB6QFANCNFSM4IIW4V7A> .