A Rust library for capturing system audio output on macOS using the audiotee binary. This library provides a convenient wrapper around the command-line tool, making it easy to capture, process, and save system audio in your Rust applications.

• Real-time audio capture: Capture system audio output as PCM data streams
• Event-driven API: React to audio data, start/stop events, and errors through callbacks
• Configurable parameters: Control sample rate, chunk duration, and process filtering
• WAV file export: Built-in support for saving captured audio as WAV files
• Thread-safe: Safe to use in multi-threaded applications
• macOS only: Specifically designed for macOS system audio capture

Add this to your Cargo.toml:

[dependencies]
audiotee = "0.1.0"

• macOS: This library only works on macOS
• audiotee binary: The audiotee command-line tool must be installed and accessible in your PATH
• Rust: 1.70 or later

use audiotee::{AudioTee, AudioTeeOptions};
use std::sync::{Arc, Mutex};

fn main() {
    // Configure options
    let options = AudioTeeOptions {
        sample_rate: Some(16_000),
        chunk_duration_ms: Some(1000),
        mute: Some(false),
        include_processes: None,
        exclude_processes: None,
    };

    // Buffer to accumulate audio data
    let audio_buffer: Arc<Mutex<Vec<u8>>> = Arc::new(Mutex::new(Vec::new()));
    let audio_buffer_clone = Arc::clone(&audio_buffer);

    // Create AudioTee instance with event handlers
    let mut tee = AudioTee::new(options)
        .on_start(|| println!("Started capturing audio"))
        .on_stop(|| println!("Stopped capturing audio"))
        .on_error(|e| eprintln!("Error: {e}"))
        .on_data(move |chunk| {
            let mut buffer = audio_buffer_clone.lock().unwrap();
            buffer.extend_from_slice(&chunk.data);
        });

    // Start capturing
    tee.start().expect("Failed to start AudioTee");

    // Capture for some time...
    std::thread::sleep(std::time::Duration::from_secs(10));

    // Stop capturing
    tee.stop().expect("Failed to stop AudioTee");
}

The AudioTeeOptions struct allows you to customize the audio capture behavior:

• sample_rate: Sample rate in Hz (e.g., 16000, 44100, 48000)
• chunk_duration_ms: Duration of each audio chunk in milliseconds
• mute: Whether to mute system audio output during capture
• include_processes: List of process IDs to include in capture (whitelist)
• exclude_processes: List of process IDs to exclude from capture (blacklist)

Check out the examples directory for more comprehensive usage examples:

cargo run --example main

This will demonstrate:

• Starting and stopping audio capture
• Saving audio chunks periodically
• Exporting captured audio as WAV files

This library is built on top of the audiotee command-line tool. Special thanks to Nick Payne and his excellent article: AudioTee: Capture System Audio Output on macOS.

Contributions are welcome! Please feel free to submit a Pull Request.

This project is licensed under the MIT License - see the LICENSE file for details.