ambisonic

Compose and play 3D audio.

The ambisonic library provides 3D sound scene support on top of rodio. It allows positioning and moving sound sources freely in 3D space around a virtual listener, and playing the resulting spatial mix in real-time over a sound card.

Features

• Realistic directional audio
• Take rodio sound sources and place them in space
• Doppler effect on moving sounds

Gallery

• Video that demonstrates spatial audio in a 3D graphics scene by @bjadamson

Usage

Add this to your Cargo.toml:

[dependencies]
ambisonic = "0.4.0"

Usage Example

Ambisonic can generate a sine wave for you:

use std::thread::sleep;
use std::time::Duration;
use ambisonic::{rodio, AmbisonicBuilder};

let scene = AmbisonicBuilder::default().build();
let source = rodio::source::SineWave::new(440);
let mut sound = scene.play_at(source, [50.0, 1.0, 0.0]);

// move sound from right to left
sound.set_velocity([-10.0, 0.0, 0.0]);
for i in 0..1000 {
    sound.adjust_position([50.0 - i as f32 / 10.0, 1.0, 0.0]);
    sleep(Duration::from_millis(10));
}
sound.set_velocity([0.0, 0.0, 0.0]);

Since Ambisonic is built ontop of Rodio, any file format that Rodio supports can also be loaded and positioned in 3D space.

let file = std::fs::File::open("path/to/your/file.wav").unwrap();
let source = rodio::Decoder::new(std::io::BufReader::new(file)).unwrap();
let source = source.repeat_infinite();

let mut sound = scene.play_at(source.convert_samples(), [50.0, 1.0, 0.0]);

// move sound from right to left
sound.set_velocity([-10.0, 0.0, 0.0]);
for i in 0..1000 {
    sound.adjust_position([50.0 - i as f32 / 10.0, 1.0, 0.0]);
    sleep(Duration::from_millis(10));
}
sound.set_velocity([0.0, 0.0, 0.0]);

Technical Details

ambisonic is built around the concept of an intermediate representation of the sound field, called B-format. The B-format describes what the listener should hear, independent of their audio playback equipment. This leads to a clear separation of audio scene composition and rendering. For details, see Wikipedia.

In its current state, the library allows spatial composition of single-channel rodio sources into a first-order B-format stream. The chosen renderer then decodes the B-format stream into audio signals for playback.

Currently, the following renderers are available:

• Stereo: simple and efficient playback on two stereo speakers or headphones
• HRTF: realistic 3D sound over headphones using head related transfer functions

Although at the moment only stereo output is supported, the B-format abstraction should make it easy to implement arbitrary speaker configurations in the future.

Learning Resources

https://github.com/mbillingr/ambisonic/blob/master/documents/info.md

License

Licensed under either of

• Apache License, Version 2.0 (LICENSE-APACHE or http://www.apache.org/licenses/LICENSE-2.0)
• MIT license (LICENSE-MIT or http://opensource.org/licenses/MIT)

at your option.

Contribution

Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in the work by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.