Get few seconds black screen when switching to empty mid roll with DRM protected video

[z423821123]

[REQUIRED] Issue description

Playing DRM protected video in empty mid roll will appear about 1 seconds black screen. It's easy to reproduce in demo app.

[REQUIRED] Reproduction steps

1. Add this ads tag uri "https://vastsynthesizer.appspot.com/empty-midroll-2" info DRM protected video in demo app

"name": "Widevine DASH (MP4, H264)",
    "samples": [
      {
        "name": "HD (cenc)",
        "uri": "https://storage.googleapis.com/wvmedia/cenc/h264/tears/tears.mpd",
        "drm_scheme": "widevine",
        "drm_license_uri": "https://proxy.uat.widevine.com/proxy?provider=widevine_test",
        "ad_tag_uri": "https://vastsynthesizer.appspot.com/empty-midroll-2"
      },
      {
        "name": "UHD (cenc)",
        "uri": "https://storage.googleapis.com/wvmedia/cenc/h264/tears/tears_uhd.mpd",
        "drm_scheme": "widevine",
        "drm_license_uri": "https://proxy.uat.widevine.com/proxy?provider=widevine_test"
      },
      {
        "name": "HD (cbcs)",
        "uri": "https://storage.googleapis.com/wvmedia/cbcs/h264/tears/tears_aes_cbcs.mpd",
        "drm_scheme": "widevine",
        "drm_license_uri": "https://proxy.uat.widevine.com/proxy?provider=widevine_test"
      },
      {
        "name": "UHD (cbcs)",
        "uri": "https://storage.googleapis.com/wvmedia/cbcs/h264/tears/tears_aes_cbcs_uhd.mpd",
        "drm_scheme": "widevine",
        "drm_license_uri": "https://proxy.uat.widevine.com/proxy?provider=widevine_test"
      },
      {
        "name": "Secure -> Clear -> Secure (cenc)",
        "uri": "https://storage.googleapis.com/exoplayer-test-media-1/widevine/tears_enc_clear_enc.mpd",
        "drm_scheme": "widevine",
        "drm_license_uri": "https://proxy.uat.widevine.com/proxy?provider=widevine_test",
        "drm_session_for_clear_content": true
      }
    ]
  }

2.Click HD(cenc)

3.Found that frame become black about 1 seconds with the second empty mid roll

[REQUIRED] Version

2.13.0

[REQUIRED] Device

Samsung Galaxy S10, Android 10

[icbaker]

I can't reproduce what you're seeing with a Pixel 3a XL.

However I suspect it might be related to switching between secure and clear decoders. Can you try adding "drm_session_for_clear_content": true to the same JSON snippet and see what happens?

{
  "name": "HD (cenc)",
  "uri": "https://storage.googleapis.com/wvmedia/cenc/h264/tears/tears.mpd",
  "drm_scheme": "widevine",
  "drm_license_uri": "https://proxy.uat.widevine.com/proxy?provider=widevine_test",
  "ad_tag_uri": "https://vastsynthesizer.appspot.com/empty-midroll-2",
  "drm_session_for_clear_content": true
},

More info: https://exoplayer.dev/drm.html#drm-sessions-for-clear-content

[z423821123]

Still reproduce in demo app when I adding "drm_session_for_clear_content": true to the JSON. I will email the attachment to dev.exoplayer@gmail.com

[icbaker]

Thanks for trying that - sorry it didn't work. I took a closer look and realised the drm_session_for_clear_content flag isn't properly propagated all the way down when using the MediaItem API. I've sent a change to fix that.

I determined I couldn't reproduce because the symptom is device specific - a colleague was able to reproduce with their Samsung device.

[z423821123]

Thanks for your support,But I tested 2.13.1 and it still getting black frame 1 seconds when the timeline approaches empty vast ad break, and I pass "drm_session_for_clear_content": true value to JSON haven't any help.

I assume that AdsMediaSource has update source information which is AD_STATE_ERROR AdPlaybackState via maybeUpdateSourceInfo().

 private void maybeUpdateSourceInfo() {
    @Nullable Timeline contentTimeline = this.contentTimeline;
    if (adPlaybackState != null && contentTimeline != null) {
      adPlaybackState = adPlaybackState.withAdDurationsUs(getAdDurationsUs());
      Timeline timeline =
          adPlaybackState.adGroupCount == 0
              ? contentTimeline
              : new SinglePeriodAdTimeline(contentTimeline, adPlaybackState);
      refreshSourceInfo(timeline);
    }
  }

@icbaker @ojw28

[icbaker]

You're right - there's two different things interacting here and we only fixed one of them.

Specifically when the mid-roll is empty we still release and re-initialize the (secure) video decoder.

With "drm_session_for_clear_content": false you can see the secure decoder being released and replaced by an insecure video decoder for each non-empty midroll (10s and 30s). But at the empty one (12.2s) we just release & immediately reacquire the secure decoder:

videoDecoderInitialized [eventTime=1.19, mediaPos=0.00, window=0, period=0, c2.qti.avc.decoder.secure]               
videoDecoderReleased [eventTime=11.71, mediaPos=0.00, window=0, period=0, adGroup=0, ad=0, c2.qti.avc.decoder.secure]
videoDecoderInitialized [eventTime=11.81, mediaPos=0.00, window=0, period=0, adGroup=0, ad=0, c2.qti.avc.decoder]    
videoDecoderReleased [eventTime=21.75, mediaPos=10.00, window=0, period=0, c2.qti.avc.decoder]                       
videoDecoderInitialized [eventTime=21.87, mediaPos=10.00, window=0, period=0, c2.qti.avc.decoder.secure]             
videoDecoderReleased [eventTime=24.05, mediaPos=12.21, window=0, period=0, c2.qti.avc.decoder.secure]                
videoDecoderInitialized [eventTime=24.38, mediaPos=12.21, window=0, period=0, c2.qti.avc.decoder.secure]             
videoDecoderReleased [eventTime=42.51, mediaPos=0.00, window=0, period=0, adGroup=2, ad=0, c2.qti.avc.decoder.secure]
videoDecoderInitialized [eventTime=42.60, mediaPos=0.00, window=0, period=0, adGroup=2, ad=0, c2.qti.avc.decoder]    
videoDecoderReleased [eventTime=52.56, mediaPos=30.00, window=0, period=0, c2.qti.avc.decoder]                       
videoDecoderInitialized [eventTime=52.66, mediaPos=30.00, window=0, period=0, c2.qti.avc.decoder.secure]             

With "drm_session_for_clear_content": true the secure decoder is kept for both the non-empty midrolls, but it's still released/reacquired at the empty one:

videoDecoderInitialized [eventTime=1.28, mediaPos=0.00, window=0, period=0, c2.qti.avc.decoder.secure]
videoDecoderReleased [eventTime=24.26, mediaPos=12.24, window=0, period=0, c2.qti.avc.decoder.secure]
videoDecoderInitialized [eventTime=24.60, mediaPos=12.24, window=0, period=0, c2.qti.avc.decoder.secure]

This is what's causing the black screen you're seeing.

I foolishly only checked that the decoder was kept for the non-empty midroll when testing (because that fires first) and didn't consider there might be a secondary behaviour that only affects empty ones.

Re-opening to track keeping decoders alive during empty mid-roll ads.

[icbaker]

The secure decoder re-initialization is fixed by removing the TODO and associated logic discussed in #8842 (comment).

I'll dupe this to that (since it affects more than just empty mid-rolls) - please follow that issue for further updates.