README.md
1# ExoPlayer Opus extension #
2
3The Opus extension provides `LibopusAudioRenderer`, which uses libopus (the Opus
4decoding library) to decode Opus audio.
5
6## License note ##
7
8Please note that whilst the code in this repository is licensed under
9[Apache 2.0][], using this extension also requires building and including one or
10more external libraries as described below. These are licensed separately.
11
12[Apache 2.0]: https://github.com/google/ExoPlayer/blob/release-v2/LICENSE
13
14## Build instructions (Linux, macOS) ##
15
16To use this extension you need to clone the ExoPlayer repository and depend on
17its modules locally. Instructions for doing this can be found in ExoPlayer's
18[top level README][].
19
20In addition, it's necessary to build the extension's native components as
21follows:
22
23* Set the following environment variables:
24
25```
26cd "<path to exoplayer checkout>"
27EXOPLAYER_ROOT="$(pwd)"
28OPUS_EXT_PATH="${EXOPLAYER_ROOT}/extensions/opus/src/main"
29```
30
31* Download the [Android NDK][] and set its location in an environment variable.
32 This build configuration has been tested on NDK r20.
33
34```
35NDK_PATH="<path to Android NDK>"
36```
37
38* Fetch libopus:
39
40```
41cd "${OPUS_EXT_PATH}/jni" && \
42git clone https://git.xiph.org/opus.git libopus
43```
44
45* Run the script to convert arm assembly to NDK compatible format:
46
47```
48cd ${OPUS_EXT_PATH}/jni && ./convert_android_asm.sh
49```
50
51* Build the JNI native libraries from the command line:
52
53```
54cd "${OPUS_EXT_PATH}"/jni && \
55${NDK_PATH}/ndk-build APP_ABI=all -j4
56```
57
58[top level README]: https://github.com/google/ExoPlayer/blob/release-v2/README.md
59[Android NDK]: https://developer.android.com/tools/sdk/ndk/index.html
60
61## Build instructions (Windows) ##
62
63We do not provide support for building this extension on Windows, however it
64should be possible to follow the Linux instructions in [Windows PowerShell][].
65
66[Windows PowerShell]: https://docs.microsoft.com/en-us/powershell/scripting/getting-started/getting-started-with-windows-powershell
67
68## Notes ##
69
70* Every time there is a change to the libopus checkout:
71 * Arm assembly should be converted by running `convert_android_asm.sh`
72 * Clean and re-build the project.
73* If you want to use your own version of libopus, place it in
74 `${OPUS_EXT_PATH}/jni/libopus`.
75
76## Using the extension ##
77
78Once you've followed the instructions above to check out, build and depend on
79the extension, the next step is to tell ExoPlayer to use `LibopusAudioRenderer`.
80How you do this depends on which player API you're using:
81
82* If you're passing a `DefaultRenderersFactory` to `SimpleExoPlayer.Builder`,
83 you can enable using the extension by setting the `extensionRendererMode`
84 parameter of the `DefaultRenderersFactory` constructor to
85 `EXTENSION_RENDERER_MODE_ON`. This will use `LibopusAudioRenderer` for
86 playback if `MediaCodecAudioRenderer` doesn't support the input format. Pass
87 `EXTENSION_RENDERER_MODE_PREFER` to give `LibopusAudioRenderer` priority over
88 `MediaCodecAudioRenderer`.
89* If you've subclassed `DefaultRenderersFactory`, add a `LibopusAudioRenderer`
90 to the output list in `buildAudioRenderers`. ExoPlayer will use the first
91 `Renderer` in the list that supports the input media format.
92* If you've implemented your own `RenderersFactory`, return a
93 `LibopusAudioRenderer` instance from `createRenderers`. ExoPlayer will use the
94 first `Renderer` in the returned array that supports the input media format.
95* If you're using `ExoPlayer.Builder`, pass a `LibopusAudioRenderer` in the
96 array of `Renderer`s. ExoPlayer will use the first `Renderer` in the list that
97 supports the input media format.
98
99Note: These instructions assume you're using `DefaultTrackSelector`. If you have
100a custom track selector the choice of `Renderer` is up to your implementation,
101so you need to make sure you are passing an `LibopusAudioRenderer` to the
102player, then implement your own logic to use the renderer for a given track.
103
104## Using the extension in the demo application ##
105
106To try out playback using the extension in the [demo application][], see
107[enabling extension decoders][].
108
109[demo application]: https://exoplayer.dev/demo-application.html
110[enabling extension decoders]: https://exoplayer.dev/demo-application.html#enabling-extension-decoders
111
112## Links ##
113
114* [Javadoc][]: Classes matching `com.google.android.exoplayer2.ext.opus.*`
115 belong to this module.
116
117[Javadoc]: https://exoplayer.dev/doc/reference/index.html
118