Rosegarden is a free software digital audio workstation program developed for Linux with ALSA and Qt4. Developed by Chris Cannam, Richard Bown, Guillaume Laurent, et al.
License: Open Source
Sekaiju is primarily focused on MIDI sequencing with a powerful set of features for professionals, while Rosegarden offers a more comprehensive solution for both audio and MIDI, making it more user-friendly but potentially less focused for dedicated MIDI tasks.