phonic

phonic is a cross-platform audio playback and DSP library for Rust. It provides a flexible, low-latency audio engine and DSP tools for desktop and web-based music application development.

Originally developed for the AFEC-Explorer app, phonic was created to provide precise playback position monitoring - a feature lacking in other Rust audio libraries at the time. It is now also used in the experimental algorithmic sequencer pattrns as the default sample playback engine.

Note

phonic has not yet reached a stable version, so expect breaking changes.

Features

• Cross-Platform Audio Playback:

  • Play audio on Windows, macOS, and Linux via cpal.
  • WebAssembly support for in-browser audio via emscripten.
  • WAV file output for rendering computed audio to a file instead of playing it back.

• Flexible Audio Source Handling:

  • Play, seek, stop, and mix preloaded (buffered) or streamed (on-the-fly decoded) audio files.
  • Support for most common audio formats through Symphonia.
  • Seamless loop playback using loop points from WAV and FLAC files.
  • Automatic resampling and channel mapping via a fast custom resampler and Rubato.

• Advanced Playback Control:

  • Sample-precise scheduling for accurate sequencing.
  • Real-time monitoring of playback position and status for GUI integration.
  • Dynamic control over volume, panning, and playback speed via Sync + Send playback handles.

• Custom Synthesis and DSPs:

  • Play preloaded sample files via a basic sampler.
  • Play custom-built synthesizers or one-shot synth sounds using the optional fundsp integration.
  • Apply custom-built or use built-in DSP effects: gain, filter, eq, reverb, chorus, compressor, limiter, distortion.
  • Build simple or complex DSP graphs by routing audio through optional sub-mixers.
  • DSP effects are automatically bypassed to save CPU cycles when they receive no audible input.

Documentation

Rust docs for the last published versions are available at https://docs.rs/phonic

Examples

See /examples directory for more examples.

File Playback with Monitoring

Play, seek, and stop audio files on the default audio output device. Monitor playback status of playing files.

use std::{time::Duration, sync::mpsc::sync_channel};

use phonic::{
    DefaultOutputDevice, Player, PlaybackStatusEvent, Error,
    FilePlaybackOptions, SynthPlaybackOptions
};

fn main() -> Result<(), Error> {
    // Create a player with the default output device and a channel to receive playback events.
    let (playback_status_sender, playback_status_receiver) = sync_channel(32);
    let mut player = Player::new(DefaultOutputDevice::open()?, playback_status_sender);

    // Start playing a file: The file below is going to be "preloaded" because it uses the
    // default playback options. Preloaded means it's entirely decoded first, then played back
    // from a decoded buffer. All files played through the player are automatically resampled
    // and channel-mapped to match the audio output's signal specs.
    // Preloaded files can also be cheaply cloned, so they can be allocated once and played back
    // many times too. The returned handle allows changing playback properties of the files.
    let small_file = player.play_file(
        "PATH_TO/some_small_file.wav",
        FilePlaybackOptions::default())?;

    // The next file is going to be decoded and streamed on the fly, which is especially handy
    // for long files, as it can start playing right away and won't need to allocate memory
    // for the entire file.
    let long_file = player.play_file(
        "PATH_TO/some_long_file.mp3",
        FilePlaybackOptions::default()
            .streamed()
            .volume_db(-6.0)
            .speed(0.5)
            .repeat(2),
    )?;

    // You can optionally track playback status events from the player.
    std::thread::spawn(move || {
        while let Ok(event) = playback_status_receiver.recv() {
            match event {
                PlaybackStatusEvent::Position { id, path, context: _, position } => {
                    // `context` is an optional, user-defined payload, which can be passed
                    // along to the status with `player.play_file_with_context`
                    println!("Playback pos of source #{id} '{path}': {pos}",
                        pos = position.as_secs_f32()
                    );
                }
                PlaybackStatusEvent::Stopped { id, path, context: _, exhausted, } => {
                    if exhausted {
                        println!("Playback of #{id} '{path}' finished");
                    } else {
                        println!("Playback of #{id} '{path}' was stopped");
                    }
                }
            }
        }
    });

    // The returned handles allow controlling playback properties of playing files.
    // The second arg is an optional sample time, where `None` means immediately.
    long_file.seek(Duration::from_secs(5), None)?;

    // Using Some sample time args, we can schedule changes (sample-accurate).
    let now = player.output_sample_frame_position();
    let samples_per_second = player.output_sample_rate() as u64;

    // Use the handle's `is_playing` function to check if a file is still playing.
    if long_file.is_playing() {
        long_file.set_volume(0.3, now + samples_per_second)?; // Fade down after 1 second
        long_file.stop(now + 2 * samples_per_second)?;  // Stop after 2 seconds
    }

    // If you only want one file to play at the same time, stop all playing sounds.
    player.stop_all_sources()?;
    // And then schedule a new source for playback.
    let _boom = player.play_file("PATH_TO/boom.wav", FilePlaybackOptions::default())?;

    Ok(())
}

File Playback with DSP Effects in a Mixer Graph

Create DSP graphs by routing sources through different mixers and effects.

use phonic::{
    DefaultOutputDevice, Player, Error, FilePlaybackOptions,
    effects::{ChorusEffect, ReverbEffect}
};

fn main() -> Result<(), Error> {
    // Create a player with the default output device.
    let mut player = Player::new(DefaultOutputDevice::open()?, None);

    // Add a reverb effect to the main mixer. All sounds played without a
    // specific target mixer will now be routed through this effect.
    let reverb = player.add_effect(ReverbEffect::with_parameters(0.6, 0.8), None)?;

    // Create a new sub-mixer that is a child of the main mixer.
    let chorus_mixer_id = player.add_mixer(None)?;
    // Add a chorus effect to this new mixer. Sources routed to this mixer will
    // now apply the chorus effect and reverb (the main mixer effects).
    let chorus = player.add_effect(ChorusEffect::default(), chorus_mixer_id)?;

    // Effect parameters can be automated via the returned handles.
    // The `None` arguments are optional sample times to schedule events.
    reverb.set_parameter(ReverbEffect::ROOM_SIZE.id(), 0.9f32, None)?;
    chorus.set_parameter_normalized(ChorusEffect::RATE.id(), 0.5, None)?;

    // Play a file through the main mixer (which has reverb only).
    let _some_file = player.play_file(
        "PATH_TO/some_file.wav",
        FilePlaybackOptions::default(),
    )?;

    // Play another file through the chorus mixer (and main mixer with the reverb FX).
    let _another_file = player.play_file(
        "PATH_TO/another_file.wav",
        FilePlaybackOptions::default().target_mixer(chorus_mixer_id),
    )?;

    Ok(())
}

Contributing

Patches are welcome! Please fork the latest git repository and create a feature or bugfix branch.

License

phonic is distributed under the terms of the GNU Affero General Public License V3.