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.

This repository also includes an ncw to wav conversion cli tool, ncw-convert.

Requirements

• Rust 1.58 or higher

Usage

use ncw::{NcwReader, SampleFormat};

let input = File::open(&args[1])?;
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. 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)),
    }
}

Utility (ncw-convert)

To install the cli utility, you can use cargo:

cargo install ncw-convert

Usage

Run the program with the following command-line arguments:

ncw-convert <INPUT> <OUTPUT>

• <INPUT>: Path to the input NCW file.
• <OUTPUT>: Path where the output WAV file will be saved.

Contribution

To contribute, create a pull request with your proposed changes.