Untracker

Untracker is a high-quality stem extraction tool for tracker music modules (MOD, S3M, XM, IT, etc.). It leverages the libopenmpt extension API to provide true isolation for instruments and samples, ensuring that each extracted stem is clean and free from interference from other tracks.

Features

• True Isolation: Uses the OpenMPT Interactive Interface to mute/unmute instruments at the engine level.
• Broad Format Support: Supports all formats handled by libopenmpt (over 400 formats).
• Flexible Output: Supports WAV, Ogg Vorbis, Opus, and FLAC (feature-gated).
• Smart Detection: Automatically detects whether to use instrument-based or sample-based isolation.
• Parallel Processing: Extract multiple stems simultaneously with the --parallel flag.
• High-Quality Resampling: Multiple resampling methods available (nearest, linear, cubic, sinc).
• Customizable Audio Quality: Adjustable sample rate, bit depth, and format-specific settings.

Installation

Prerequisites

• Rust (latest stable)
• libopenmpt-dev and pkg-config (Linux/macOS)

Building

Standard build (requires libopenmpt installed on the system):

cargo build --release

Static build (builds libopenmpt from source and bundles it):

make static

Usage

untracker --input my_module.xm --output-dir ./stems --format wav

Command Line Options

  -i, --input <INPUT>
          Input module file path
  -o, --output-dir <OUTPUT_DIR>
          Output directory for stem files
      --sample-rate <SAMPLE_RATE>
          Sample rate [default: 44100]
      --channels <CHANNELS>
          Number of channels (1 or 2) [default: 2]
      --resample <RESAMPLE>
          Resampling method [default: sinc] [possible values: nearest, linear, cubic, sinc]
      --format <FORMAT>
          Output format: wav, vorbis, opus, flac [default: wav]
      --bit-depth <BIT_DEPTH>
          Bit depth for lossless formats (16 or 24) [default: 16]
      --opus-bitrate <OPUS_BITRATE>
          Bitrate for Opus format in kbps [default: 128]
      --vorbis-quality <VORBIS_QUALITY>
          Vorbis quality level (0-10) [default: 5]
      --stereo-separation <STEREO_SEPARATION>
          Stereo separation in percent (0-200) [default: 100]
  -p, --parallel
          Render stems in parallel
  -h, --help
          Print help
  -V, --version
          Print version

Audio Formats

• WAV: Uncompressed PCM audio (default format)
• Vorbis: Ogg Vorbis compressed audio (requires vorbis feature)
• Opus: Opus compressed audio (requires opus feature)
• FLAC: Lossless compressed audio (requires flac feature)

Advanced Options

• Sample Rate: Supports any sample rate (though Opus is limited to 8, 12, 16, 24, or 48 kHz)
• Channels: 1 (mono) or 2 (stereo)
• Resampling: Choose from nearest neighbor, linear, cubic, or sinc interpolation
• Stereo Separation: Adjust left/right channel separation (0% = mono, 100% = normal, 200% = exaggerated)
• Bit Depth: 16-bit or 24-bit for lossless formats
• Opus Bitrate: Custom bitrate from 64 kbps to 512 kbps
• Vorbis Quality: Scale from 0 (lowest) to 10 (highest)

Examples

Extract stems in WAV format:

untracker -i song.xm -o stems/

Extract with high-quality 24-bit FLAC output:

untracker -i song.it -o stems/ --format flac --bit-depth 24

Extract with parallel processing for faster results:

untracker -i song.mod -o stems/ --parallel

Extract with custom settings (48kHz, stereo, high quality):

untracker -i song.s3m -o stems/ --sample-rate 48000 --format vorbis --vorbis-quality 9

License

This project is licensed under the BSD-3-Clause-Attribution License.