# 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 ##

To use this extension you need to clone the ExoPlayer repository and depend on
its modules locally. Instructions for doing this can be found in ExoPlayer's
[top level README][]. In addition, it's necessary to build the extension's
native components as follows:

* 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:

```
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
```

* Checkout the appropriate branches of libvpx and libyuv (the scripts and
  makefiles bundled in this repo are known to work only at these versions of the
  libraries - we will update this periodically as newer versions of
  libvpx/libyuv are released):

```
cd "${VP9_EXT_PATH}/jni/libvpx" && \
git checkout tags/v1.6.1 -b v1.6.1 && \
cd "${VP9_EXT_PATH}/jni/libyuv" && \
git checkout 996a2bbd
```

* 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
```

[top level README]: https://github.com/google/ExoPlayer/blob/release-v2/README.md
[Android NDK]: https://developer.android.com/tools/sdk/ndk/index.html

## 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. But
  please note that `generate_libvpx_android_configs.sh` and the makefiles need
  to be modified to work with arbitrary versions of libvpx and libyuv.