🎛 Stemgen

Stemgen is a Stem file generator. Convert any track into a Stem and have fun with Traktor.

A Stem file is an open, multi-channel audio file that contains a track split into four musical elements – bass, drums, vocals, and melody, for example. With each element available independently, you have more control over the music you play.

Stemgen uses demucs to separate the 4 stems and ni-stem to create the Stem file.

Our new file contains four stems: bass, drums, vocals and other.

Why?

"It's no secret that I'm fully behind the approach to encourage individuality in creativity and for artists to play differently. Stems is a new format that mirrors my constant quest for spontaneity to drive the art of performance forwards. I hope that releasing my album From My Mind To Yours in this format, mastered by LANDR, inspires others to support the approach and bring even more flexibility to the art of DJing amongst its most progressive supporters." – Richie Hawtin

Stems are fun but nobody's releasing them. Stemgen is a way to create your own stems with only one command.

Requirement

• demucs https://github.com/facebookresearch/demucs or spleeter https://github.com/deezer/spleeter
• ffmpeg https://www.ffmpeg.org
• sox https://sox.sourceforge.net
• ni-stem (improved version provided in this repo or available at https://www.stems-music.com/stems-is-for-developers)
• jo https://github.com/jpmens/jo
• imagemagick https://imagemagick.org if you want to crop covers

Usage

• Clone this repo (downloading instead of cloning loses permissions to execute files)
• $ ./stemgen -i track.wav or drag and drop a track on stemgen-droplet
• Have fun! Your new .stem.m4a file is in output dir
• Supported input file format are .wav .wave .aif .aiff .flac

Quick install on macOS

• brew install coreutils ffmpeg sox jo imagemagick
• pip install demucs or pip install spleeter
• echo "alias stemgen=/Documents/stemgen/stemgen" >> ~/.zshrc

How to use the droplet

Pro tip: you can put the droplet in your dock

• Drag and drop a single track, multiple tracks or a directory on the stemgen-droplet

How to customize and re-create the droplet

I included a slightly modified version of AppleScript-droplet. You can learn more on the repo https://github.com/RichardBronosky/AppleScript-droplet

• Edit stemgen with the OUTPUT_PATH you want for example
• Remove stemgen-droplet
• Drag and drop stemgen on the script2droplet-droplet file in Finder

or

• Edit stemgen
• cp stemgen stemgen-droplet.app/Contents/Resources/Scripts/main

Performance

• I recommend to use Demucs with the mdx_extra model. This is now the default.
• Stemgen supports 16-bit and 24-bit audio files!
• Stemgen needs to downsample the track to 44.1kHz to avoid problems with the separation software because the models are trained on 44.1kHz audio files.
• You may notice that the output file is pretty big. Apple Lossless Codec (ALAC) for audio encoding is used for lossless audio compression at the cost of increased file size.

Disclaimer

If you plan to use Stemgen on copyrighted material, make sure you get proper authorization from right owners beforehand.

License

MIT