Fix MIDI drums: only override channel if channel was not preassigned.

[lilypond.git] / lily / performance.cc

diff --git a/lily/performance.cc b/lily/performance.cc
index 0bfe37ee826581ccab7815b50afd71930725740f..59cc64a2e25c31de2d6036670de92b1c0cce71ba 100644 (file)
--- a/lily/performance.cc
+++ b/lily/performance.cc
@@ -43,6 +43,7 @@ Performance::output (Midi_stream &midi_stream)
 
   midi_stream << Midi_header (1, tracks_, clocks_per_4);
   message (_ ("Track...") + " ");
+  
   int channel = 0;
   for (vsize i = 0; i < audio_staffs_.size (); i++)
     {
@@ -50,30 +51,37 @@ Performance::output (Midi_stream &midi_stream)
       if (be_verbose_global)
        progress_indication ("[" + to_string (i));
 
-      /*
-       MIDI players tend to ignore instrument settings on
-       channel 10, the percussion channel by default.
-      */
-      if (channel % 16 == 9)
-       channel++;
+      int midi_channel =  s->channel_;
+
+      if (midi_channel < 0)
+       {
+         midi_channel = channel;
+         channel ++;
+         /*
+           MIDI players tend to ignore instrument settings on
+           channel 10, the percussion channel.
+         */
+         if (channel % 16 == 9)
+           channel ++;
+       }
 
       /*
        Huh? Why does each staff also have a separate channel? We
        should map channels to voices, not staves. --hwn.
       */
-      if (channel > 15)
+      if (midi_channel > 15)
        {
          warning (_ ("MIDI channel wrapped around"));
          warning (_ ("remapping modulo 16"));
+
+         midi_channel = midi_channel % 16; 
        }
 
-      s->output (midi_stream, channel);
-      channel ++;
+      s->output (midi_stream, midi_channel);
       if (be_verbose_global)
        progress_indication ("]");
     }
 }
-
 void
 Performance::add_element (Audio_element *p)
 {