moq-audio

The audio half of a native call: microphone in, hang track out, speaker at the far end. Everything is Rust, so there is no C toolchain, CMake step, or codec to install.

Module	Does
capture	Microphones via CoreAudio, WASAPI, ALSA (and PipeWire/PulseAudio hosts), plus macOS system audio
encode	PCM to Opus (with DTX and voice-activity signaling) or raw PCM for the lowest latency
decode	Opus, PCM, and AAC-LC back to PCM, resampled to the rate you want
playback	One output device mixing every track in a call, with click-free volume ramps
aec	Acoustic echo cancellation (a port of WebRTC's), so a laptop with no headset doesn't feed itself back

Highlights:

• encode::Publication advertises the track and opens the microphone only while someone listens. Stop, swap devices, and restart without changing the track subscribers know; read a level meter for the UI.
• A/V sync signal. Sink::buffered() reports how far ahead the speaker is, which is what a video clock steers by.
• Activity per packet, read off the Opus stream, so a call UI shows who is talking without a second voice detector.
• One Linux build dependency: ALSA headers, and only when capture or playback is enabled.

let mut audio = moq_audio::decode::Consumer::new(&broadcast, &rendition, "audio", Default::default()).await?;
let engine = moq_audio::playback::Engine::open(Default::default()).await?;
let mut sink = engine.sink(moq_audio::playback::Input { sample_rate: audio.sample_rate(), channels: audio.channels(), ..Default::default() })?;
while let Some(frame) = audio.read().await? {
    sink.write(&frame.data)?;
}

cargo add moq-audio --features playback                # decode and play the example above
cargo add moq-audio --features capture,playback,aec    # microphone, speaker, echo cancellation (Linux: cpal links libasound)

API: docs.rs/moq-audio. Pair with moq-video.