HLS: Playback re-buffers when toggling audio/closed-caption tracks

[ChmielowiecAlek]

Description:

• playback hangs for ~3 seconds when switching Closed Captions on
• internally, a new SelectionOverride is used to enable Closed Captions by calling DefaultTrackSelector.setSelectionOverride
• the player goes through an additional buffering state

Precondition:

• a high-bandwidth network connection has been established

Reproduction steps:

• run ExoPlayer demo application
• select HLS and Apple16x9 basic stream
• the playback is fluent
• tap on the sceen to show buttons and press Text
• switch from Default to CEA-608 and press OK
• state changes to buffering and there is about 3 seconds long gap

Expected result:

• Closed Captions do appear without disturbing the playback.

Actual result:

• the playback is disturbed, re-buffering is performed.

Link to test content

https://devimages.apple.com.edgekey.net/streaming/examples/bipbop_16x9/bipbop_16x9_variant.m3u8

Version of ExoPlayer being used

r2.3.1

Device(s) and version(s) of Android being used

• Huawei P8 lite (ALE-L21), Android 6.0, API 23
• Xiaomi MIBOX3m Android 6.0.1, API 23

Logcat output captured from the device

logcat_output.txt

Bugreport

• I will send it by email

[ojw28]

Yes. This was a compromise we made deliberately in V2. We're aware it's annoying, but the way we used to achieve no disruption was technically incorrect for several reasons. We do plan to optimize it again in the future.

[ojw28]

Addressed in 06b3b3c in dev-v2.