All subtitle formats used to be enabled by default in older versions of
media3.
After the media3 library was upgraded to 1.3.0, Extractors should
specify a `SubtitleParser.Factory` explicitly. By default, no subtitle
formats are supported when using the now deprecated empty constructor of
Extractors.
Limit support to **WebVTT** and **TTML** which are the only true web
standards amongst all the subtitle formats supported by ExoPlayer.
Note that only subtitles embedded in MP4 and WebM files are supported
until Mastodon provides a way to upload subtitles separately.
This helps playing some media even if there is a problem with the
primary decoder.
E.g. [this
video](https://mastodon.social/@krzyzanowskim/112208964123517040) fails
on my Fairphone 4 without this change.
<img
src="https://github.com/tuskyapp/Tusky/assets/10157047/215d932c-9ed1-4ee8-8be7-e6ca28ddec23"
width="200"/>
<details>
<summary>Stacktrace</summary>
```
androidx.media3.exoplayer.ExoPlaybackException: MediaCodecVideoRenderer error, index=0, format=Format(1, null, null, video/avc, avc1.640034, -1, null, [1920, 1440, 119.99593, ColorInfo(BT709, Limited range, sRGB, false, 8bit Luma, 8bit Chroma)], [-1, -1]), format_supported=YES
at androidx.media3.exoplayer.ExoPlayerImplInternal.handleMessage(ExoPlayerImplInternal.java:620)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loopOnce(Looper.java:201)
at android.os.Looper.loop(Looper.java:288)
at android.os.HandlerThread.run(HandlerThread.java:67)
Caused by: androidx.media3.exoplayer.mediacodec.MediaCodecRenderer$DecoderInitializationException: Decoder init failed: OMX.qcom.video.decoder.avc, Format(1, null, null, video/avc, avc1.640034, -1, null, [1920, 1440, 119.99593, ColorInfo(BT709, Limited range, sRGB, false, 8bit Luma, 8bit Chroma)], [-1, -1])
at androidx.media3.exoplayer.mediacodec.MediaCodecRenderer.maybeInitCodecWithFallback(MediaCodecRenderer.java:1114)
at androidx.media3.exoplayer.mediacodec.MediaCodecRenderer.maybeInitCodecOrBypass(MediaCodecRenderer.java:551)
at androidx.media3.exoplayer.mediacodec.MediaCodecRenderer.onInputFormatChanged(MediaCodecRenderer.java:1560)
at androidx.media3.exoplayer.video.MediaCodecVideoRenderer.onInputFormatChanged(MediaCodecVideoRenderer.java:1152)
at androidx.media3.exoplayer.mediacodec.MediaCodecRenderer.readSourceOmittingSampleData(MediaCodecRenderer.java:994)
at androidx.media3.exoplayer.mediacodec.MediaCodecRenderer.render(MediaCodecRenderer.java:814)
at androidx.media3.exoplayer.video.MediaCodecVideoRenderer.render(MediaCodecVideoRenderer.java:940)
at androidx.media3.exoplayer.ExoPlayerImplInternal.doSomeWork(ExoPlayerImplInternal.java:1102)
at androidx.media3.exoplayer.ExoPlayerImplInternal.handleMessage(ExoPlayerImplInternal.java:541)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loopOnce(Looper.java:201)
at android.os.Looper.loop(Looper.java:288)
at android.os.HandlerThread.run(HandlerThread.java:67)
Caused by: android.media.MediaCodec$CodecException: Error 0xfffffff4
at android.media.MediaCodec.native_configure(Native Method)
at android.media.MediaCodec.configure(MediaCodec.java:2215)
at android.media.MediaCodec.configure(MediaCodec.java:2131)
at androidx.media3.exoplayer.mediacodec.AsynchronousMediaCodecAdapter.initialize(AsynchronousMediaCodecAdapter.java:174)
at androidx.media3.exoplayer.mediacodec.AsynchronousMediaCodecAdapter.access$100(AsynchronousMediaCodecAdapter.java:54)
at androidx.media3.exoplayer.mediacodec.AsynchronousMediaCodecAdapter$Factory.createAdapter(AsynchronousMediaCodecAdapter.java:119)
at androidx.media3.exoplayer.mediacodec.DefaultMediaCodecAdapterFactory.createAdapter(DefaultMediaCodecAdapterFactory.java:117)
at androidx.media3.exoplayer.mediacodec.MediaCodecRenderer.initCodec(MediaCodecRenderer.java:1195)
at androidx.media3.exoplayer.mediacodec.MediaCodecRenderer.maybeInitCodecWithFallback(MediaCodecRenderer.java:1103)
at androidx.media3.exoplayer.mediacodec.MediaCodecRenderer.maybeInitCodecOrBypass(MediaCodecRenderer.java:551)
at androidx.media3.exoplayer.mediacodec.MediaCodecRenderer.onInputFormatChanged(MediaCodecRenderer.java:1560)
at androidx.media3.exoplayer.video.MediaCodecVideoRenderer.onInputFormatChanged(MediaCodecVideoRenderer.java:1152)
at androidx.media3.exoplayer.mediacodec.MediaCodecRenderer.readSourceOmittingSampleData(MediaCodecRenderer.java:994)
at androidx.media3.exoplayer.mediacodec.MediaCodecRenderer.render(MediaCodecRenderer.java:814)
at androidx.media3.exoplayer.video.MediaCodecVideoRenderer.render(MediaCodecVideoRenderer.java:940)
at androidx.media3.exoplayer.ExoPlayerImplInternal.doSomeWork(ExoPlayerImplInternal.java:1102)
at androidx.media3.exoplayer.ExoPlayerImplInternal.handleMessage(ExoPlayerImplInternal.java:541)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loopOnce(Looper.java:201)
at android.os.Looper.loop(Looper.java:288)
at android.os.HandlerThread.run(HandlerThread.java:67)
```
</details>
Currently, ExoPlayer is initialized explicitly in `ViewMediaFragment`
with all its dependencies, including many that are not useful for
viewing Mastodon media attachments.
This pull request moves most ExoPlayer initialization and configuration
to a new Dagger module, and instead a `Provider<ExoPlayer>` factory is
injected in the Fragment so it can create new instances when needed.
The following ExoPlayer components will be configured:
- **Renderers**: all of them (audio, video, metadata, subtitles) except
for the `CameraMotionRenderer`.
- **Extractors**: FLAC, Wav, Mp4, Ogg, Matroska/WebM and MP3 containers,
to provide the same support as Firefox or Chrome browsers. Other
container formats that are either image formats (already covered by
Glide), not web-friendly or reserved for live streaming are skipped.
- **MediaSource**: only progressive download (through OkHttp) is
provided. Live streaming support using protocols like RTSP, MPEG/Dash or
HLS is skipped, because Mastodon servers don't use these protocols to
download attachments.
The Mastodon documentation mentions the [supported media formats for
attachments](https://docs.joinmastodon.org/user/posting/#media) and this
covers them and even more. The docs also mentions that the video and
audio files are transcoded to MP4 and MP3 upon upload but that was not
the case in the past (for example WebM was used) and it could change
again in the future.
Specifying these components manually allows reducing the APK size by
about 200 KB thanks to R8 shrinking.
There are also a few extra code changes:
- Remove the code specific to API < 24 since the min SDK of the app is
now 24.
- Add support for pausing a video when unplugging headphones.
- Specify the audio attributes according to content type to help the
Android audio mixer.
Christophe Beyls
Konrad Pozniak