KMid initially ran in Linux and FreeBSD using the OSSv3 MIDI sequencer. The release 1.0 coincided with the KDE1 publication in 1998, and version 2.0 with KDE2 in 2000. It was ported later to KDE3. Version 2.0 and was functionally very similar to KMid2, having already ALSA support.
I've started using KDE by 2002, along with the initial KDE3 releases. At that time I also became involved in the development of Rosegarden, a KDE program for music edition using MIDI technology, and used KMid frequently. The main drawback was the inability of teaming KMid with other ALSA sequencer based programs, because the play/pause/stop actions created and destroyed KMid's MIDI ports, preventing reliable external connections made by other programs like aconnect or qjackctl.
In Akademy-es 2006, that was held in Barcelona, I met Antonio and explained him my concerns about KMid, and subsequently exchanged some patches by email trying to solve the implementation of libkmid regarding the ALSA sequencer. However, any solution explored involved binary incompatibilities, so the issue was out of the question within the KDE 3.5 development cycle.
On the other hand, KDE4 development started and OSSv4 was published, so there was no need to support OSSv3 anymore. The transfer of KMid in the SVN repository from kde-multimedia to extragear provided more time and freedom to rethink the software architecture and develop a new implementation.
KMid2 was developed as a revamping of the original KMid, with the following main features and goals:
- Playback to external MIDI devices.
- Allow to use software synths as well, like TiMidity++ and FluidSynth.
- Change tempo and volume controls. Add a key (transpose) control.
- Independent MIDI channel mute control.
- Support for many character encodings for lyrics, and configurable fonts.
- Remove the deprecated OSSv3 /dev/sequencer interface support, dropped from OSSv4 anyway.
- A fair ALSA sequencer backend implementation: do not create/destroy the client and port instances on each play/pause/stop action. This enables the usage of a MIDI Patch Bay application like aconnect or qjackctl.
- More native backends for other platforms.