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Imported from GitHub PR https://github.com/androidx/media/pull/1826 Merge 6b59a1602b022ebc44411ae3440e274c51c223a7 into b5615d5e919b297def6450b45320a3165c34548c COPYBARA_INTEGRATE_REVIEW=https://github.com/androidx/media/pull/1826 from androidx:mpegh_extension 6b59a1602b022ebc44411ae3440e274c51c223a7 PiperOrigin-RevId: 689417378
90 lines
3.7 KiB
Markdown
90 lines
3.7 KiB
Markdown
# MPEG-H decoder module
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The MPEG-H module provides `MpeghAudioRenderer`, which uses the libmpegh native
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library to decode MPEG-H audio.
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## License note
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Please note that while the code in this repository is licensed under
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[Apache 2.0][], using this module also requires building and including the
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[Fraunhofer GitHub MPEG-H decoder][] which is licensed under the Fraunhofer
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GitHub MPEG-H decoder project.
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[Apache 2.0]: ../../LICENSE
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[Fraunhofer GitHub MPEG-H decoder]: https://github.com/Fraunhofer-IIS/mpeghdec
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## Build instructions (Linux, macOS)
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To use the module you need to clone this GitHub project and depend on its
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modules locally. Instructions for doing this can be found in the
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[top level README][].
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In addition, it's necessary to fetch libmpegh library as follows:
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* Set the following environment variables:
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```
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cd "<path to project checkout>"
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MPEGH_MODULE_PATH="$(pwd)/libraries/decoder_mpegh/src/main"
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```
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* Fetch libmpegh library:
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```
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cd "${MPEGH_MODULE_PATH}/jni" && \
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git clone https://github.com/Fraunhofer-IIS/mpeghdec.git --branch r2.0.0 libmpegh
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```
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* [Install CMake][].
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Having followed these steps, gradle will build the module automatically when run
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on the command line or via Android Studio, using [CMake][] and [Ninja][] to
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configure and build mpeghdec and the module's [JNI wrapper library][].
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[top level README]: ../../README.md
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[Install CMake]: https://developer.android.com/studio/projects/install-ndk
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[CMake]: https://cmake.org/
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[Ninja]: https://ninja-build.org
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[JNI wrapper library]: src/main/jni/mpeghdec_jni.cc
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## Build instructions (Windows)
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We do not provide support for building this module on Windows, however it should
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be possible to follow the Linux instructions in [Windows PowerShell][].
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[Windows PowerShell]: https://docs.microsoft.com/en-us/powershell/scripting/getting-started/getting-started-with-windows-powershell
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## Using the module with ExoPlayer
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Once you've followed the instructions above to check out, build and depend on
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the module, the next step is to tell ExoPlayer to use `MpeghAudioRenderer`. How
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you do this depends on which player API you're using:
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* If you're passing a `DefaultRenderersFactory` to `ExoPlayer.Builder`, you
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can enable using the module by setting the `extensionRendererMode` parameter
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of the `DefaultRenderersFactory` constructor to
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`EXTENSION_RENDERER_MODE_ON`. This will use `MpeghAudioRenderer` for
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playback if `MediaCodecAudioRenderer` doesn't support the input format. Pass
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`EXTENSION_RENDERER_MODE_PREFER` to give `MpeghAudioRenderer` priority over
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`MediaCodecAudioRenderer`.
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* If you've subclassed `DefaultRenderersFactory`, add a `MpeghAudioRenderer`
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to the output list in `buildAudioRenderers`. ExoPlayer will use the first
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`Renderer` in the list that supports the input media format.
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* If you've implemented your own `RenderersFactory`, return a
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`MpeghAudioRenderer` instance from `createRenderers`. ExoPlayer will use the
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first `Renderer` in the returned array that supports the input media format.
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* If you're using `ExoPlayer.Builder`, pass a `MpeghAudioRenderer` in the
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array of `Renderer`s. ExoPlayer will use the first `Renderer` in the list
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that supports the input media format.
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Note: These instructions assume you're using `DefaultTrackSelector`. If you have
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a custom track selector the choice of `Renderer` is up to your implementation,
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so you need to make sure you are passing an `MpeghAudioRenderer` to the player,
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then implement your own logic to use the renderer for a given track.
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## Links
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* [Troubleshooting using decoding extensions][]
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[Troubleshooting using decoding extensions]: https://developer.android.com/media/media3/exoplayer/troubleshooting#how-can-i-get-a-decoding-library-to-load-and-be-used-for-playback
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