39544f34b4
On some systems, the SDL audio callback is not called frequently enough (for example it requests 5ms of samples every 10ms), because the output buffer is too small. By default, we want to use a small value (5ms) to minimize latency and buffer underrun, but if it does not work well, users need a way to increase it. Refs #3793 <https://github.com/Genymobile/scrcpy/issues/3793>
101 lines
2.7 KiB
Markdown
101 lines
2.7 KiB
Markdown
# Audio
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Audio forwarding is supported for devices with Android 11 or higher, and it is
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enabled by default:
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- For **Android 12 or newer**, it works out-of-the-box.
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- For **Android 11**, you'll need to ensure that the device screen is unlocked
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when starting scrcpy. A fake popup will briefly appear to make the system
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think that the shell app is in the foreground. Without this, audio capture
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will fail.
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- For **Android 10 or earlier**, audio cannot be captured and is automatically
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disabled.
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If audio capture fails, then mirroring continues with video only (since audio is
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enabled by default, it is not acceptable to make scrcpy fail if it is not
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available), unless `--require-audio` is set.
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## No audio
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To disable audio:
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```
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scrcpy --no-audio
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```
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## Codec
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The audio codec can be selected. The possible values are `opus` (default), `aac`
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and `raw` (uncompressed PCM 16-bit LE):
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```bash
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scrcpy --audio-codec=opus # default
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scrcpy --audio-codec=aac
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scrcpy --audio-codec=raw
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```
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Several encoders may be available on the device. They can be listed by:
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```bash
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scrcpy --list-encoders
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```
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To select a specific encoder:
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```
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scrcpy --audio-codec=opus --audio-encoder='c2.android.opus.encoder'
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```
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For advanced usage, to pass arbitrary parameters to the [`MediaFormat`],
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check `--audio-codec-options` in the manpage or in `scrcpy --help`.
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[`MediaFormat`]: https://developer.android.com/reference/android/media/MediaFormat
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## Bit rate
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The default video bit-rate is 128Kbps. To change it:
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```bash
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scrcpy --audio-bit-rate=64K
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scrcpy --audio-bit-rate=64000 # equivalent
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```
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_This parameter does not apply to RAW audio codec (`--audio-codec=raw`)._
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## Buffering
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Audio buffering is unavoidable. It must be kept small enough so that the latency
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is acceptable, but large enough to minimize buffer underrun (causing audio
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glitches).
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The default buffer size is set to 50ms. It can be adjusted:
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```bash
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scrcpy --audio-buffer=40 # smaller than default
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scrcpy --audio-buffer=100 # higher than default
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```
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Note that this option changes the _target_ buffering. It is possible that this
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target buffering might not be reached (on frequent buffer underflow typically).
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If you don't interact with the device (to watch a video for example), a higher
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latency (for both [video](video.md#buffering) and audio) might be preferable to
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avoid glitches and smooth the playback:
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```
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scrcpy --display-buffer=200 --audio-buffer=200
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```
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It is also possible to configure another audio buffer (the audio output buffer),
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by default set to 5ms. Don't change it, unless you get some [robotic and glitchy
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sound][#3793]:
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```bash
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# Only if absolutely necessary
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scrcpy --audio-output-buffer=10
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```
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[#3793]: https://github.com/Genymobile/scrcpy/issues/3793
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