Known Limitations

This has been tested with:

Audio cards

  • MOTU UltraLite-mk5
  • Behringer X32 (through X-Live card)
  • Behringer Wing Rack

MIDI

  • MOTU UltraLite-mk5
  • Roland UM-ONE
  • CME U6MIDI Pro

DMX

DMX is expected to be well supported through OLA, but the devices that have been explicitly tested:

  • Entec DMX USB Pro
  • RatPac Satellite (Art-Net and sACN)
  • Cinelex Skycast A (sACN)

MIDI Beat Clock

The MIDI beat clock uses a dedicated real-time thread to deliver 24-ppqn timing messages. Accurate tempo requires elevated thread priority:

  • Linux: Requires CAP_SYS_NICE for SCHED_FIFO real-time scheduling. The systemd service unit grants this automatically. Without it, jitter may increase under load.
  • macOS: Crossplatform thread priority elevation works without special privileges. POSIX SCHED_FIFO is not available on macOS CoreAudio threads; this is expected and does not affect timing.

The thread priority can be tuned with MTRACK_THREAD_PRIORITY (0–99, default 70) or disabled entirely with MTRACK_DISABLE_RT_AUDIO=1.

Web UI File Management

The web UI’s song management, file upload, lighting editor, and playlist editor features require all project files to reside under a single project root directory (the directory containing mtrack.yaml). Files referenced via absolute paths or on separate mounts will play back correctly but cannot be edited, uploaded to, or managed through the web UI.

mtrack must have write access to the project root directory for management features to work. On read-only filesystems, playback and monitoring work but editing is disabled.

General disclaimer

This is my first Rust project, so this is likely cringey, horrible non-idiomatic Rust. Feel free to submit PRs to make this better.