# ExoPlayer VP9 Extension #

## Description ##

The VP9 Extension is a [Renderer][] implementation that helps you bundle libvpx
(the VP9 decoding library) into your app and use it along with ExoPlayer to play
VP9 video on Android devices.

[Renderer]: https://google.github.io/ExoPlayer/doc/reference/com/google/android/exoplayer2/Renderer.html

## Build Instructions ##

* Checkout ExoPlayer along with Extensions:

```
git clone https://github.com/google/ExoPlayer.git
```

* Set the following environment variables:

```
cd "<path to exoplayer checkout>"
EXOPLAYER_ROOT="$(pwd)"
VP9_EXT_PATH="${EXOPLAYER_ROOT}/extensions/vp9/src/main"
```

* Download the [Android NDK][] and set its location in an environment variable:

[Android NDK]: https://developer.android.com/tools/sdk/ndk/index.html

```
NDK_PATH="<path to Android NDK>"
```

* Fetch libvpx and libyuv:

```
cd "${VP9_EXT_PATH}/jni" && \
git clone https://chromium.googlesource.com/webm/libvpx libvpx && \
git clone https://chromium.googlesource.com/libyuv/libyuv libyuv
```

* Run a script that generates necessary configuration files for libvpx:

```
cd ${VP9_EXT_PATH}/jni && \
./generate_libvpx_android_configs.sh "${NDK_PATH}"
```

* Build the JNI native libraries from the command line:

```
cd "${VP9_EXT_PATH}"/jni && \
${NDK_PATH}/ndk-build APP_ABI=all -j4
```

* In your project, you can add a dependency to the VP9 Extension by using a the
  following rule:

```
// in settings.gradle
include ':..:ExoPlayer:library'
include ':..:ExoPlayer:extension-vp9'

// in build.gradle
dependencies {
    compile project(':..:ExoPlayer:library')
    compile project(':..:ExoPlayer:extension-vp9')
}
```

* Now, when you build your app, the VP9 extension will be built and the native
  libraries will be packaged along with the APK.

## Notes ##

* Every time there is a change to the libvpx checkout:
  * Android config scripts should be re-generated by running
    `generate_libvpx_android_configs.sh`
  * Clean and re-build the project.
* If you want to use your own version of libvpx or libyuv, place it in
  `${VP9_EXT_PATH}/jni/libvpx` or `${VP9_EXT_PATH}/jni/libyuv` respectively.

