Buffering after updating AdPlaybackState with ad data

Version

ExoPlayer 2.16.1

More version details

Our repo forked from the version above

Devices that reproduce the issue

Multiple devices
Emulator Medium Phone API 33
Read device Tablet Android 11
Many user devices

Devices that do not reproduce the issue

N/A

Reproducible in the demo app?

No

Reproduction steps

Summary

We are implementing AdsLoader that will provide our ad data to the player
Our ad data is not known from the beginning, so we initialize AdPlaybackState with empty ad groups.
During content playback we obtain the actual ad data and update the ad group with it before it is reached.
After we update the new AdPlaybackState with the actual ad data (time + media uri) we observe the player starts buffering. How can we avoid this buffering?

Details

As ad breaks are not know on initialization so we allocate empty ad groups like this:

val midrollPlaceholders = LongArray(adBreakCount) { Long.MAX_VALUE }
adPlaybackState = AdPlaybackState(adsId, *midrollPlaceholders)

Marking all uninitialized ad groups as skipped

adPlaybackState.withSkippedAdGroup(adGroupIndex)

If the uninitialized ad groups are not marked as skipped, the playback gets stuck.

Later we resolve the ad break data and update upcoming ad group in some time ahead (e.g. one minute):

adPlaybackState.withAdGroupTimeUs(adGroupIndex, adGroupStartTime)
adPlaybackState.withAdCount(adGroupIndex, adCount)
adPlaybackState.withAdUri(adGroupIndex, adIndexInAdGroup, uri)

And updating the adPlaybackState to player:

AdsLoader.EventListener.onAdPlaybackState(adPlaybackState)

After this, we are observing ~1 sec buffering in the player

Player.Listener fun onPlaybackStateChanged(playbackState: Int) // STATE_BUFFERING

when the buffering is done (STATE_READY), content playing continues and the ad group plays once reached

What can we do to avoid this buffering when updating the ad group?

It looks like the player is buffering the content rather than the new ad group,
but there is no change expected in the content playback data.

Expected result

There should be no additional buffering of the content when AdPlaybackState is updated
The updated ad group is few minutes ahead, so it should have no impact on current content playback.

Actual result

After this, we are observing ~1 sec buffering in the player

What can we do to avoid this buffering when updating the ad group?

It looks like the player is buffering the content rather than the new ad group,
but there is no change expected in the content playback data.

Media

The bug was reproducible with any media. E.g.
https://devstreaming-cdn.apple.com/videos/streaming/examples/img_bipbop_adv_example_ts/master.m3u8

Bug Report

• You will email the zip file produced by adb bugreport to android-media-github@google.com after filing this issue.