Crash happening on 2.13.0: ArrayIndexOutOfBoundsException in maybeUpdateAdMediaSources

[priscila225]

I want to report a crash using exoplayer v2.13.0 and googleIMA 3.22.0. It's a TV app in which we have a DAI video and other VOD videos with prerolls/midrolls. Not sure if it's crashing on live video (DAI) or VOD.
Since we updated Exoplayer to 2.13.0 this crash started happening:

Fatal Exception: java.lang.ArrayIndexOutOfBoundsException
length=0; index=1
com.google.android.exoplayer2.source.ads.AdsMediaSource.maybeUpdateAdMediaSources (AdsMediaSource.java:316)
com.google.android.exoplayer2.source.ads.AdsMediaSource.onAdPlaybackState (AdsMediaSource.java:295)
com.google.android.exoplayer2.source.ads.AdsMediaSource.access$100 (AdsMediaSource.java:58)
com.google.android.exoplayer2.source.ads.AdsMediaSource$ComponentListener.lambda$onAdPlaybackState$0 (AdsMediaSource.java:385)
com.google.android.exoplayer2.source.ads.AdsMediaSource$ComponentListener.lambda$onAdPlaybackState$0$AdsMediaSource$ComponentListener (AdsMediaSource.java:7)
com.google.android.exoplayer2.source.ads.-$$Lambda$AdsMediaSource$ComponentListener$0n-PEDqeEt9IJPXJ3J126o4e0MQ.run (-.java:7)
android.os.Handler.handleCallback (Handler.java:751)
android.os.Handler.dispatchMessage (Handler.java:95)
android.os.Looper.loop (Looper.java:154)
android.os.HandlerThread.run (HandlerThread.java:61)

I believe this might be a crash in the Exo SDK itself since we're not seeing any reference to our code in the stack trace, but even if it's not could you provide me any information on what could be causing this, as well as any tips to fix it?

• ExoPlayer version 2.13.0
• IMA version 3.22.0
• Android 7 47% of crashes
• Android 5 45% of crashes
• Android 9 8% of crashes
• Android device: Amazon AFTT/AFTTM

[tonihei]

Andrew, could you take a look?

[cadalt]

we are seeing this crash pretty frequently since upgrading to 2.13.0 as well! so fixing it would be much appreciated!

[cadalt]

this crash is still happening on 2.13.2

[priscila225]

^ Yes I can confirm this is occurring on the Exo latest version 2.13.2 version with ima 3.22.2 latest version too

[victorraft]

@andrewlewis do you think maybe this can be happening because the if statement in line 315-318 is missing an array size check before accessing adPlaybackState.adGroups[adGroupIndex]?

[andrewlewis]

I'm planning to look into this today. Yes, there may is probably a size check missing, but I want to find the code path that's causing the size to be out of synch just to make sure this isn't a symptom of another bug.

[andrewlewis]

For anyone seeing this crash, is there a code path in your app where ImaAdsLoader.release() is called before Player.release()? I am working on the assumption that the problem is caused by the way ImaAdsLoader updates the ad playback state to have 0 ads when it's released, but if the error is reproducible in an app that doesn't do that then the assumption isn't correct.

[victorraft]

@andrewlewis Yes, our code has this function:

override fun playItemAtPlaylistIndex(index: Int) {
        releaseAdsLoader()
        releasePlayer()

And according to some logs we got this function was the last one that was executed before the crash stacktrace, so I think you migh be onto something here!

Do you think inverting the order of these calls might help? We're looking for a solution that doesn't involve waiting for the next Exo release, so if you could suggest some workaround that's good enough that would be much appreciated!
Thank you!

[andrewlewis]

Yes! When the ads loader is released, it removes all cue points from the AdPlaybackState and that causes a crash because AdsMediaSource tries to access information about cue points that have disappeared. (There could be another cause but I haven't found it yet.)

[cadalt]

for the record, this must be something new caused by 2.13.0 though, right?
just clarifying because this code where ImaAdsLoader.release() is called before Player.release() has been there for a long time

[andrewlewis]

for the record, this must be something new caused by 2.13.0 though, right?

Yes. This probably stopped working in 69dad31, which went into 2.13.0.

[andrewlewis]

To clarify, I'm planning to fix the bug anyway (at which either ordering should work again), but if you need a quick fix without waiting for an ExoPlayer release or patch then swapping the order of the calls should do it.