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androidx / media

Jetpack Media3 support libraries for media use cases, including ExoPlayer, an extensible media player for Android
https://developer.android.com/media/media3
Apache License 2.0
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Seamless transitions to clipped items with a second decoder #1400

Open GlebPBanuba opened 4 months ago

GlebPBanuba commented 4 months ago

Version

Media3 main branch

More version details

No response

Devices that reproduce the issue

All

Devices that do not reproduce the issue

No response

Reproducible in the demo app?

Yes

Reproduction steps

We are experiencing the serious issue while playing video by trimmed media sources within single video. Let's say there is a video (60 seconds) and the user wants to trim the video by selecting a number of sources in the video i.e.

  1. 500 ms - 2000ms
  2. 4000ms - 3000ms
  3. 6200 ms - 7950ms
  4. ... N. 55000ms - 59000ms

The player does not play these source smoothly while using ConcatenatingMediaSource and ConcatenatingMediaSource2.

This sample https://github.com/Banuba/android-media3-issue-concatenating is prepared to clearly demonstrate the issue.

PTAL and advice how to mitigate an impact of this issue.

Expected result

No long visible freezes

Actual result

Long freezes while playing a number of trimmed media source within one video

Media

This sample https://github.com/Banuba/android-media3-issue-concatenating is prepared to clearly demonstrate the issue. Zip file with the sample is attached as well. android-media3-issue-concatenating.zip android-media3-issue-concatenating.zip

Bug Report

tonihei commented 3 months ago

Thanks for sharing the example project!

The reason for what you are seeing is that each item is played independently. Each individual clip needs to decode samples from the previous keyframe to start at the correct frame. By default, ExoPlayer uses a single codec for a playback, so at every transition there is small gap where the codec needs to process all the samples from the previous keyframe that are not shown on screen.

We are working on improvements that allow to use a second decoder for these types of transitions. This way the second decoder can already decode the required samples for the next clip and the transitions can become seamless again. This is still work in progress though, so I'll mark it an enhancement. @microkatz not sure if there is already another enhancement tracking this support, feel free to de-duplicate if so.