fraggle
Super Moderator

Posts: 6568
Registered: 07-00 |
sgtcrispy said:
Please pardon the bump and my ignorance on this question.
Just curious to what the GENMIDI lump does exactly and why it needs to be replaced/changed.
Back when people all had "SoundBlaster-compatible" sound cards, Doom's MIDI music was played back using the OPL synthesizer chip found on the SoundBlaster (and all its successors and clones). The OPL chip isn't a MIDI chip, it's essentially just 11 FM synthesizers (basically, programmable noise-making boxes).
So to play a MIDI note, you program the chip with a set of register values that will make a noise that sounds like the appropriate instrument, at the frequency corresponding to the note that's being played. The GENMIDI lump is a table of these register values, one for each of the instruments in the General MIDI instrument set. So for example, suppose the MIDI file says to play a guitar note, you might look up entry #25 in the table, program the OPL chip with those values, and it makes a noise somewhat reminiscent of a guitar.
Doom's GENMIDI lump is particularly good compared to other sets (as used by other games, etc). The one in Freedoom is converted from the instrument set used by the OpenBSD kernel (mainly because the license matched up with Freedoom's license), and it's pretty horrible. Ideally it would be nice to have some better instruments, but most source ports nowadays don't even support OPL playback - probably because most sound cards don't even have an OPL chip any more and there are much higher quality options for MIDI playback (Timidity, etc).
Csonicgo said:
also Fraggle I would love to help assist in that. I would need a better interface (AT3 is apparently in the works) and support for 4op or double-voice patches.... or I could suck it up and learn ATII's instrument editor.
If you can put together a few instruments that you think are better, I'll be more inclined to put in the effort. I don't want to go to the effort just to end up having my time wasted :-)
EDIT: There seem to be some more instrument editors linked here (I haven't tried them)
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