# Ausnd
[](https://github.com/karip/ausnd/actions/workflows/cross-test.yml)
Rust library to read and write
Sun/Next [AU audio format](https://en.wikipedia.org/wiki/Au_file_format).
Features:
- read AU files
- write AU files
- reading infinite AU streams
- no heap memory allocations
- no unsafe code
- no panicking
- supports uncompressed integer and floating point samples
- supports compression types: μ-law and A-law
- supports audio streams larger than 4 gigabytes
Out of scope:
- conversion between different sample formats (e.g., i16 to f32). There's
[so many ways](http://blog.bjornroche.com/2009/12/int-float-int-its-jungle-out-there.html)
to do the conversion that it's better that this crate doesn't do it.
## Usage
Reading an AU audio file:
```rust, no_run
let mut bufrd = std::io::BufReader::new(std::fs::File::open("test.au").expect("File error"));
let mut reader = ausnd::AuReader::new(&mut bufrd).expect("Read error");
let info = reader.read_info().expect("Invalid header");
for sample in reader.samples().expect("Can't read samples") {
println!("Got sample {:?}", sample.expect("Sample error"));
}
```
Writing an AU audio file (with the default 2 channels, 16-bit signed integer samples,
sample rate 44100):
```rust, no_run
let mut bufwr = std::io::BufWriter::new(std::fs::File::create("test.au").expect("File error"));
let winfo = ausnd::AuWriteInfo::default();
let mut writer = ausnd::AuWriter::new(&mut bufwr, &winfo).expect("Write header error");
writer.write_samples_i16(&[ 1, 2, 3, 4 ]).expect("Write sample error");
writer.finalize().expect("Finalize error");
```
See [the ausnd API documentation](https://docs.rs/ausnd/) for details.
## Examples
A simple AU player using `ausnd::AuReader` and [tinyaudio](https://crates.io/crates/tinyaudio):
```sh
cd examples/ausnd-tinyaudio
cargo run filename.au
```
A simple audio processor for volume and noise effects using `AuStreamParser` and `AuWriter`:
```sh
cargo run --example ausnd-piper v0.8 n0.1 < input.au > out.au
```
The same audio processor piped from/to ffmpeg. ffmpeg converts mp3 to AU for ausnd-piper,
which writes AU for ffmpeg to convert it to mp3.
```sh
ffmpeg -i music.mp3 -f au - | cargo run --example ausnd-piper v1.5 n0.2 | ffmpeg -i - -y out.mp3
```
## Testing
[Toisto AU Test Suite](https://github.com/karip/toisto-au-test-suite) is a submodule and
needs to be fetched before running the integration tests.
```sh
cd ausnd
git submodule update --init
./tools/test.sh
```
The test should end with `--- All tests OK.`.
Performance testing:
```sh
cargo bench
```
There is a GitHub Action called "Cross-platform tests" (cross-test.yml), which automatically
runs `./tools/test.sh` for little-endian 64-bit x64_86 and big-endian 32-bit PowerPC.
## References
- [Wikipedia: Au file format](https://en.wikipedia.org/wiki/Au_file_format)
- [Oracle AU audio file format man page](https://docs.oracle.com/cd/E36784_01/html/E36882/au-4.html)
- [Audio File Formats FAQ: File Formats (archived)](https://web.archive.org/web/20230223152815/https://sox.sourceforge.net/AudioFormats-11.html#ss11.2)
- [NeXT/Sun soundfile format](http://soundfile.sapp.org/doc/NextFormat/)
- [NeXT soundstruct.h](https://github.com/johnsonjh/NeXTDSP/blob/26d2b31a6fb4bc16d55ebe17824cd2d6f9edfc7b/sound-33/soundstruct.h#L4)
- [SunOS audio_filehdr.h](https://github.com/Arquivotheca/SunOS-4.1.3/blob/413/demo/SOUND/multimedia/audio_filehdr.h)
## License
Licensed under either of Apache License, Version
2.0 or MIT license at your option.
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.