ibaker e6448f3498 Don't assume MP4 keyframe metadata is correct for CEA re-ordering
The content in Issue: androidx/media#1863 has every sample incorrectly marked as a
sync sample in the MP4 metadata, which results in flushing the
re-ordering queue on every sample, so nothing gets re-ordered, so the
subtitles are garbled.

There are currently two "uses" for this call on every keyframe:
1. It offers a safety valve if we don't read a `maxNumReorderSamples`
value from the video. Without this, the queue will just keep growing
and end up swallowing all subtitle data (similar to the bug fixed by
39c734963f).

2. When we do read (or infer) a `maxNumReorderSamples` it means we can
emit samples from the queue slightly earlier - but this is pretty
marginal, given i think the max possible value for
`maxNumReorderSamples` is 16, so the most benefit we would get is 16
frames (~0.53s at 30fps) - in most cases we will have more than 0.5s
of buffer ahead of the playback position, so the subtitles will still
get shown at the right time with no problem.

(1) is resolved in this change by setting the queue size to zero (no
reordering) if we don't have a value for `maxNumReorderSamples`.

(2) has minimal impact, so we just accept it.

We may be able to inspect the NAL unit to determine IDR vs non-IDR
instead - we will consider this as a follow-up change, but given the
minimal impact of (2) we may not pursue this.

#cherrypick

PiperOrigin-RevId: 696583702
2024-11-14 11:05:02 -08:00
2024-05-07 04:20:55 -07:00
2024-11-01 10:30:45 -07:00
2022-03-01 09:34:07 +00:00
2022-03-01 09:34:07 +00:00
2021-11-09 10:09:26 +00:00

AndroidX Media

AndroidX Media is a collection of libraries for implementing media use cases on Android, including local playback (via ExoPlayer), video editing (via Transformer) and media sessions.

Documentation

Migration for existing ExoPlayer and MediaSession projects

You'll find a migration guide for existing ExoPlayer and MediaSession users on developer.android.com.

API stability

AndroidX Media releases provide API stability guarantees, ensuring that the API surface remains backwards compatible for the most commonly used APIs. APIs intended for more advanced use cases are marked as unstable. To use an unstable method or class without lint warnings, youll need to add the OptIn annotation before using it. For more information see the UnstableApi documentation.

Using the libraries

You can get the libraries from the Google Maven repository. It's also possible to clone this GitHub repository and depend on the modules locally.

From the Google Maven repository

1. Add module dependencies

The easiest way to get started using AndroidX Media is to add gradle dependencies on the libraries you need in the build.gradle.kts file of your app module.

For example, to depend on ExoPlayer with DASH playback support and UI components you can add dependencies on the modules like this:

implementation("androidx.media3:media3-exoplayer:1.X.X")
implementation("androidx.media3:media3-exoplayer-dash:1.X.X")
implementation("androidx.media3:media3-ui:1.X.X")

Or in Gradle Groovy DSL build.gradle:

implementation 'androidx.media3:media3-exoplayer:1.X.X'
implementation 'androidx.media3:media3-exoplayer-dash:1.X.X'
implementation 'androidx.media3:media3-ui:1.X.X'

where 1.X.X is your preferred version. All modules must be the same version.

Please see the AndroidX Media3 developer.android.com page for more information, including a full list of library modules.

This repository includes some modules that depend on external libraries that need to be built manually, and are not available from the Maven repository. Please see the individual READMEs under the libraries directory for more details.

2. Turn on Java 8 support

If not enabled already, you also need to turn on Java 8 support in all build.gradle.kts files depending on AndroidX Media, by adding the following to the android section:

compileOptions {
  targetCompatibility = JavaVersion.VERSION_1_8
}

Or in Gradle Groovy DSL build.gradle:

compileOptions {
  targetCompatibility JavaVersion.VERSION_1_8
}

Locally

Cloning the repository and depending on the modules locally is required when using some libraries. It's also a suitable approach if you want to make local changes, or if you want to use the main branch.

First, clone the repository into a local directory:

git clone https://github.com/androidx/media.git

Next, add the following to your project's settings.gradle.kts file, replacing path/to/media with the path to your local copy:

(gradle as ExtensionAware).extra["androidxMediaModulePrefix"] = "media3-"
apply(from = file("path/to/media/core_settings.gradle"))

Or in Gradle Groovy DSL settings.gradle:

gradle.ext.androidxMediaModulePrefix = 'media3-'
apply from: file("path/to/media/core_settings.gradle")

You should now see the AndroidX Media modules appear as part of your project. You can depend on them from build.gradle.kts as you would on any other local module, for example:

implementation(project(":media3-lib-exoplayer"))
implementation(project(":media3-lib-exoplayer-dash"))
implementation(project(":media3-lib-ui"))

Or in Gradle Groovy DSL build.gradle:

implementation project(':media3-lib-exoplayer')
implementation project(':media3-lib-exoplayer-dash')
implementation project(':media3-lib-ui')

MIDI module

By default the MIDI module is disabled as a local dependency, because it requires additional Maven repository config. If you want to use it as a local dependency, please configure the JitPack repository as described in the module README, and then enable building the module in your settings.gradle.kts file:

gradle.extra.apply {
  set("androidxMediaEnableMidiModule", true)
}

Or in Gradle Groovy DSL settings.gradle:

gradle.ext.androidxMediaEnableMidiModule = true

Developing AndroidX Media

Project branches

Development work happens on the main branch. Pull requests should normally be made to this branch.

The release branch holds the most recent stable release.

Using Android Studio

To develop AndroidX Media using Android Studio, simply open the project in the root directory of this repository.

Description
About Jetpack Media3 support libraries for media use cases, including ExoPlayer, an extensible media player for Android
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