Issue 1648 in lilypond: MIDI: no defined order between a simultaneous note-on and note-off

[lilypond]

Status: Accepted
Owner: ----
Labels: Type-Defect Priority-Critical Regression

New issue 1648 by address@hidden: MIDI: no defined order between a  
simultaneous note-on and note-off
http://code.google.com/p/lilypond/issues/detail?id=1648

\version "2.13.61"
\score{
  \new Staff
  << {d'' b'} \\ {b' g'} >>
  \layout {}
  \midi{}
}
produces a MIDI file with two simultaneous events on the same channel:
 the note-off for the first b' and
 the note-on for the second b'

Previously, these events were in the same midi-file track, with the  
note-off coming first, which seemed to reliably cause the note-off to be  
sent to the synthesizer first.  In 2.13.61, each voice is now stored in its  
own midi-file track, and the upper voice happens to be first.

At least one MIDI player (Windows Media Player) seems to send the note-on  
for the upper-voice b' just before the note-off for the lower-voice b',  
thus cutting off the upper-voice b'.

Workaround:
  \set Score.midiChannelMapping = #'staff


Attachments:
        1648.midi  177 bytes
        1648.png  1.7 KB