Re: Issue 1620 in lilypond: Midi overflow with instrument changes

[lilypond]

Comment #2 on issue 1620 by address@hidden: Midi overflow with  
instrument changes
http://code.google.com/p/lilypond/issues/detail?id=1620

There were formerly solutions to have MIDI output with more than 16  
staves.  Due to issues 645 and 754, and the fundamental limit of 16  
channels per MIDI output device, LilyPond files for large ensembles usually  
use two \score blocks: one for \layout and one for \midi.  (See at  
mutopiaproject.)  The \score block for midi uses 16 or fewer  
staff_performer s (either by combining staves or moving staff_performer  
from Staff to StaffGroup).

My suggestion for desired behavior:

The additional tracks may stay.
They help Jan's postprocessing, and do not seem to hurt others' use of the  
midi output. (Tracks are merely file structure, organizational information  
that does not go down the MIDI cable, and thus they should not affect  
audible output.)

MIDI channel assignments should be under user control.
The new automatic and dynamic re-assignment of staves to MIDI channels  
takes power from the users, who have use their plans to make good use of  
the 16 channels.
(I suggest we return to one MIDI channel per staff_performer, but the patch  
might be good enough.)

The example file has 16 players changing instruments.  The patch succeeds  
if it produces no "MIDI channel wrapped around" and if the woodwinds still  
sound like woodwinds  (as opposed to strings and muted trumpet) in the  
final measure.