A Python and PySide6 desktop app that helps musicians, DJs, and audio creators import songs, detect BPM and key, apply tempo/key adjustments, separate stems, and manage processed exports without modifying original audio files.

Open-source music processing app
Year
2026
Role
Open-source creator and maintainer, desktop application architecture, PySide6 UI development, audio-processing workflow design, worker-thread orchestration, native analysis helper integration, testing, documentation, packaging, and release automation
Problem
Music creators often need to prepare tracks by analyzing BPM and key, matching tempo, shifting key, separating stems, and exporting processed versions. These tasks are commonly spread across multiple tools, command-line workflows, or heavy DAW setups, making the process slow, fragmented, and difficult to repeat safely across multiple songs.
Solution
TuneMatrix provides a dedicated desktop workflow for importing multiple songs, automatically analyzing duration, BPM, key, relative key, and compatible keys, then running a structured processing pipeline for key matching, tempo matching, stem separation, and export. The app uses background Qt worker threads to keep the UI responsive, prefers a native Essentia-based analysis helper when available, falls back to librosa when needed, integrates external audio tools such as FFmpeg, Rubber Band, and Demucs, and stores project sessions in JSON for repeatable workflows.
Outcome
The project demonstrates a production-minded open-source desktop application with a responsive UI, non-destructive audio processing, automated analysis queues, dependency-aware workflow gating, project save/load support, automated tests, CI, documentation, and a cross-platform packaging foundation for future public releases.
Visual archive
A closer look at the real interfaces, states, and build details behind Tune Matrix.
Build notes
Technologies