Organ MIDI Pipeline

A Python pipeline that converts audio files to MIDI format optimized for organ music, using Demucs for audio separation and BasicPitch for transcription.

Features

• Audio Separation: Uses Demucs to separate vocals and instrumental parts
• MIDI Transcription: Converts audio to MIDI using BasicPitch
• Organ Optimization: Maps tracks to organ channels (Great, Swell, Pedal)
• UV Package Management: Uses UV for fast dependency management

Setup

1. Install UV (if not already installed):

   curl -LsSf https://astral.sh/uv/install.sh | sh

2. Install dependencies:

   make install
   # or
   uv sync

3. Add your audio file to the originals/ directory:

   cp /path/to/your/audio.mp3 originals/your_song.mp3

Usage

Run the pipeline:

# Using default file (originals/mrbrightside.mp3)
make run

# Or specify a different file
uv run python pipeline.py originals/your_song.mp3

This will:

1. Separate the audio file into 4 stems using Demucs (drums, bass, vocals, other)
2. Save separated audio files to stems/<song_name>/ directory
3. Transcribe each stem to MIDI using BasicPitch
4. Save individual MIDI files to midi_files/<song_name>/ directory
5. Merge the MIDI files with organ channel mapping
6. Output final midi_files/<song_name>/combined.mid

Output Files

After running the pipeline, you'll get:

Final Output

• midi_files/<song_name>/combined.mid - Final merged MIDI file optimized for organ

Intermediate Files

• stems/<song_name>/<song_name>_drums.wav - Separated drums audio
• stems/<song_name>/<song_name>_bass.wav - Separated bass audio
• stems/<song_name>/<song_name>_vocals.wav - Separated vocals audio
• stems/<song_name>/<song_name>_other.wav - Separated other instruments audio
• midi_files/<song_name>/drums.mid - MIDI transcription of drums
• midi_files/<song_name>/bass.mid - MIDI transcription of bass
• midi_files/<song_name>/vocals.mid - MIDI transcription of vocals
• midi_files/<song_name>/other.mid - MIDI transcription of other instruments

MIDI Channel Mapping

The generated MIDI file will have:

• Channel 0 (Pedal): Drums - Bass drum sounds
• Channel 1 (Pedal): Bass - Acoustic bass sounds
• Channel 2 (Swell): Vocals - Piano sounds in melody range
• Channel 3 (Great): Other - Piano sounds for accompaniment

Dependencies

• demucs==4.0.0
• basic-pitch==0.3.0
• torch
• torchaudio
• mido
• pretty_midi