Unexpected runtime error (When Chunks have different playlist urls)

[KostyaLyapochkin]

Hi, I have caught an unexpected runtime error when I use HLS and codecNeedsSetOutputSurfaceWorkaround = true. For example, A xiaomi device like MiBox4 returns true, because it was established in the parent class - MediaCodecVideoRenderer.

When I change the configuration of a mobile phone or hide an app - ExoPlayer passes a nullable Surface to clear/release codec inside MediaCodecVideoRenderer. The error happens when chunks have differents playlists, for instance, I dived to the source code and found out that ExoPlayer has this kind of a code’s snippet like:

HlsMediaChunk.java 139 line - Where ExoPlayer checks playlist between the last and current chunk:

playlistUrl.equals(previousChunk.playlistUrl) // so, They are not equal.

then, 144 line:

boolean canContinueWithoutSplice =
   isFollowingChunk || (isIndependent && segmentStartTimeInPeriodUs >= previousChunk.endTimeUs);

shouldSpliceIn = !canContinueWithoutSplice;

as, isFollowingChunk is false and the right block too, I have shouldSpliceIn true

and the end of all, when ExoPlayer checkes state with Assertions.class in 319 line it converts true expression to false and checks state. For example:

public int getFirstSampleIndex(int sampleQueueIndex) {
 Assertions.checkState(!shouldSpliceIn); // convert true to false


public static void checkState(boolean expression) {
 if (ExoPlayerLibraryInfo.ASSERTIONS_ENABLED && !expression) {
   throw new IllegalStateException();
 }
}

How to replay the issue:

1. You have to return true inside codecNeedsSetOutputSurfaceWorkaround method (It does not matter that you have emulators or real devices)
2. Start playing with HLS (adaptive streaming)
3. a little wait when player changes playlists between chunks (I use Charles to intercept these one’s)
4. hide or rotate an app

In conclusion, the error happens, when the method codecNeedsSetOutputSurfaceWorkaround returns true and the render has chunks with different playlist urls inside. I consider that it's normal behaviour to have different urls in a queue. Full error stack:

Caused by: java.lang.IllegalStateException
        at com.google.android.exoplayer2.util.Assertions.checkState(Assertions.java:86)
        at com.google.android.exoplayer2.source.hls.HlsMediaChunk.getFirstSampleIndex(HlsMediaChunk.java:319)
        at com.google.android.exoplayer2.source.hls.HlsSampleStreamWrapper.skipData(HlsSampleStreamWrapper.java:638)
        at com.google.android.exoplayer2.source.hls.HlsSampleStream.skipData(HlsSampleStream.java:86)
        at com.google.android.exoplayer2.BaseRenderer.skipSource(BaseRenderer.java:427)
        at com.google.android.exoplayer2.mediacodec.MediaCodecRenderer.render(MediaCodecRenderer.java:829)
        at com.google.android.exoplayer2.ExoPlayerImplInternal.doSomeWork(ExoPlayerImplInternal.java:948)
        at com.google.android.exoplayer2.ExoPlayerImplInternal.handleMessage(ExoPlayerImplInternal.java:478)
        at android.os.Handler.dispatchMessage(Handler.java:102) 
        at android.os.Looper.loop(Looper.java:193) 
        at android.os.HandlerThread.run(HandlerThread.java:65) 

[ojw28]

Note: Looks like a duplicate of #8890.

[christosts]

@tonihei can you take a look?

[tonihei]

Yes, this is a bug introduced by 8349d78 (in 2.13.0). The method getFirstSampleIndex is not allowed to be called for spliced-in chunks (as we don't know the first sample index in this case) and we need to avoid calling this method for all chunks.

We'll provide a fix soon.

[KostyaLyapochkin]

@tonihei Thanks for the feedback!

[tonihei]

Issue should be fixed by the two commits above.