
DefaultTrackSelector
This change aims to prioritise tracks that have a 'smooth enough for video' frame rate, without always selecting the track with the highest frame rate. In particular MP4 files extracted from motion photos sometimes have two HEVC tracks, with the higher-res one having a very low frame rate (not intended for use in video playback). Before this change `DefaultTrackSelector` would pick the low-fps, high-res track. This change adds a somewhat arbitrary 10fps threshold for "smooth video playback", meaning any tracks above this threshold are selected in preference to tracks below it. Within the tracks above the threshold other attributes are used to select the preferred track. We deliberately don't pick the highest-fps track (over pixel count and bitrate), because most users would prefer to see a 30fps 4k track over a 60fps 720p track. This change also includes a test MP4 file, extracted from the existing `jpeg/pixel-motion-photo-2-hevc-tracks.jpg` file by logging `mp4StartPosition` in [`MotionPhotoDescription.getMotionPhotoMetadata`](b930b40a16/libraries/extractor/src/main/java/androidx/media3/extractor/jpeg/MotionPhotoDescription.java (L123)
) and then using `dd`: ``` mp4StartPosition=2603594 $ dd if=jpeg/pixel-motion-photo-2-hevc-tracks.jpg \ of=mp4/pixel-motion-photo-2-hevc-tracks.mp4 \ bs=1 \ skip=2603594 ``` ---- This solution is in addition to the `JpegMotionPhotoExtractor` change made specifically for these two-track motion photos in5266c71b3a
. We will keep both changes, even though that change is not strictly needed after this one, because adding the role flags helps to communicate more clearly the intended usage of these tracks. This change to consider FPS seems like a generally useful improvement to `DefaultTrackSelector`, since it seems unlikely we would prefer a 5fps video track over a 30fps one. Issue: androidx/media#1051 PiperOrigin-RevId: 611015459
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
- The developer guide provides a wealth of information.
- The class reference documents the classes and methods.
- The release notes document the major changes in each release.
- The media dev center provides samples and guidelines.
- Follow our developer blog to keep up to date with the latest developments!
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, you’ll 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
}
3. Enable multidex
If your Gradle minSdkVersion
is 20 or lower, you should
enable multidex in order
to prevent build errors.
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
cd media
Next, add the following to your project's settings.gradle.kts
file, replacing
path/to/media
with the path to your local copy:
gradle.extra.apply {
set("androidxMediaModulePrefix", "media-")
}
apply(from = file("path/to/media/core_settings.gradle"))
Or in Gradle Groovy DSL settings.gradle
:
gradle.ext.androidxMediaModulePrefix = 'media-'
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(":media-lib-exoplayer"))
implementation(project(":media-lib-exoplayer-dash"))
implementation(project(":media-lib-ui"))
Or in Gradle Groovy DSL build.gradle
:
implementation project(':media-lib-exoplayer')
implementation project(':media-lib-exoplayer-dash')
implementation project(':media-lib-ui')
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.