Drumstick is a set of GPLv3 licensed C++/Qt libraries for MIDI applications. The project includes several tools as examples, and among them is the drumstick-guiplayer utility that leverages the Drumstick::ALSA library, so it is available only for Linux (because the ALSA sequencer is a linux only technology). Some people have complained that they would like to run a program with the same functionalities on Windows and macOS. And here it is...
Key features:
- MIDI Output to hardware MIDI ports, or any other Drumstick backend
- Transpose song tonality between -12 and +12 semitones
- Change MIDI volume level (using MIDI CC7)
- Scale song speed between half and double tempo
Git repoository:
https://github.com/pedrolcl/dmidiplayer
Downloads for Linux, Windows and macOS:
https://github.com/pedrolcl/dmidiplayer/releases/tag/v1.0.0 