Audio playback library

Rust playback library.

Playback is handled by cpal. Format decoding is handled by Symphonia by default, or by optional format-specific decoders:

• FLAC by claxon.
• MP3 by minimp3.
• Vorbis by lewton.
• WAV by hound.

See the feature flags for more details on formats, and other features.

Documentation

The documentation contains an introduction to the library.

Breaking Changes

We have written an upgrade guide. It will help you upgrade to rodio 0.21.

Examples

We are always making changes to rodio. This can mean that the examples do not work with the current crates.io release. You will have to look at the examples from commit f7aa48d. They are available on github.

Requirements

Rodio playback works in environments supported by cpal library.

The CPU of the target system should have hardware support for 32-bit floating point (f32), and atomic operations that are at least 32 bit wide. Without these the CPU may not be fast enough to keep up with real-time.

Dependencies (Linux only)

Rodio uses cpal library to send audio to the OS for playback. ALSA development files are needed to build cpal on Linux. These are provided as part of the libasound2-dev package on Debian and Ubuntu distributions and alsa-lib-devel on Fedora.

Minimal build

It is possible to build rodio without support for audio playback. In this configuration cpal dependency and its requirements are excluded. This configuration may be useful, for example, for decoding and processing audio in environments when the audio output is not available (e.g. in case of Linux, when ALSA is not available). See into_file example that works with this build.

In order to use rodio in this configuration disable default features and add the necessary ones. In this case the Cargo.toml dependency would look like:

[dependencies]
rodio = { version = "0.21.0", default-features = false, features = ["symphonia-all"] }

Cross compling aarch64/arm

Through cpal rodio depends on the alsa library (libasound & libasound-dev), this can make crosscompiling hard. Cpal has some guides on crosscompling in their Readme (https://github.com/RustAudio/cpal). They are missing instructions on aarch64 (arm linux) so we have some here:

aarch64/arm on Debian like (Ubuntu/pop)

• Install crossbuild-essential-arm64: sudo apt-get install crossbuild-essential-arm64 clang
• Add the aarch64 target for rust: rustup target add aarch64-unknown-linux-gnu
• Add the architecture arm64 to apt using: sudo dpkg --add-architecture arm64
• Install the multi-arch version of libasound2-dev for arm64 using: sudo apt install libasound2-dev:arm64
• Build with the pkg config sysroot set to /usr/aarch64-linux-gnu and aarch64-linux-gnu as linker: PKG_CONFIG_SYSROOT_DIR=/usr/aarch64-linux-gnu RUSTFLAGS="-C linker=aarch64-linux-gnu-gcc" cargo build --target aarch64-unknown-linux-gnu

This will work for other Linux targets too if you change the architecture in the command and if there are multi-arch packages available.

You might want to look at cross if you are running on a non debian system or want to make this more repeatable.

Contributing

We love it when people join making rodio better. There are many ways to help not matter how experienced you are with audio or Rust. We would especially love help with:

• Reviewing PR's: we rely on the community to keep rodio correct, fast and maintainable. Absolutely anyone is welcome to leave reviews. Anyone can catch missing or unnecessary tests, unclear docs logic mistakes etc.
• Improving the docs: You only learn something for the first time once. Many of us forgot what was hard when things where new. Your experience using rodio for the first time can really help out here. You probably know best what needs clearification and how it should be written down. It can be anything, maybe a paragraph on audio theory or an extra example.
• Adding features: we love it when we get new features or existing onces get even better. Let us know what you are working on early. Not only can the rest of the community help out with the design we can help make the review and merge smooth. Please see our Contributing Guide for more to get you started.

License

Licensed under either of

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

at your option.

License of your contributions

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.