Native Instruments NCW Audio File Format

Description

NCW (Native Instruments Compressed Wave) is a lossless compression algorithm developed by Native Instruments which is essentially DPCM and bit truncation.

This library is a zero-dependency Rust-based library to decode NCW files. It serves as part of a wider reverse engineering effort of proprietary audio formats, and this particular library is used in ni-file, a library for Native Instruments file formats support in rust.

The repository also ships ncw-convert, a command-line NCW to WAV converter built on this crate.

Requirements

• Rust 1.85 or higher (edition 2024)

Usage

use ncw::{NcwReader, SampleFormat};

fn main() -> Result<(), Box<dyn std::error::Error>> {
    let input = std::fs::File::open("sample.ncw")?;
    let mut ncw = NcwReader::read(input)?;

    println!("channels: {}", ncw.header.channels);
    println!("sample_rate: {}", ncw.header.sample_rate);
    println!("bits_per_sample: {}", ncw.header.bits_per_sample);

    // Samples are interleaved i32 in plain channel order; mid/side encoded
    // blocks are converted to left/right for you. PCM files give
    // sign-extended integers at the file's bit depth; float files give raw
    // f32 bit patterns.
    for sample in ncw.decode_samples()? {
        match ncw.sample_format {
            SampleFormat::Pcm => println!("{sample}"),
            SampleFormat::Float => println!("{}", f32::from_bits(sample as u32)),
        }
    }
    Ok(())
}

Contribution

Pull requests are welcome. If you have Kontakt libraries at hand, the most valuable contribution right now is test material: see the Help wanted section of the repository README.