Adhoc Audio

Audio compression written in pure rust. It Doesn't link to any bindings so its buildable for wasm32-unknown-unknown.

What is this?

Its an audio codec I cobbled together for compressing audio. I am not a compression gigachad so the codec isn't that great.

Why?

During the development of a WASM application I was writing the need suddenly arose to compress microphone data coming from the WEBAUDIO api. To keep building the project simple I needed the encoder to be written in pure rust. AFAIK, there are a few pure rust audio decoders for things like VORBIS(lewton) ,MP3(puremp3) etc but most of those crates do not support encoding.

Performance

Probably not very good, I haven't really tested this.

Compression

Compression savings seems to be anywhere from 30%-70% but i haven't dont extensive testing to say concretely. The codec is not lossy, however, it does quantize the audio on higher "compression-levels" to make significant space savings. Quantization doesn't effect audio quality too badly, I was pretty suprised at that discovery.

Encode Example

use adhoc_audio::{codec::Streamable, AdhocCodec, WavCodec};
use std::fs::File;

fn main() {
    println!("compressing file example..");
    
    //set up a buffer for reading/writing samples
    let mut samples = [0.0; 1024];

    //open wav file
    let mut wav_reader = WavCodec::load(File::open("./resources/taunt.wav")
        .unwrap()).unwrap();

    let mut adhoc = AdhocCodec::new()
        .with_compression_level(7)
        // AdhocCodec::with_info(.. ) MUST BE CALLED 
        // before calling encode/decode when you are 
        // creating a new instance of AdhocCodec
        .with_info(wav_reader.info());

    //'decode' wav stream bit-by-bit
    //Note:in this case we are just reading PCM info
    while let Some(samples_read) = wav_reader.decode(&mut samples) {
        //encode wav data bit-by-bit
        //memory is allocated as needed
        adhoc.encode(&samples[0..samples_read]);
    }

    //write compressed audio back to disk
    adhoc
        .save_to(File::create("./resources/taunt.adhoc").unwrap())
        .unwrap();

    println!("taunt.adhoc written to: ./resources");
}

Decode

check 'decompress.rs' in example folder