comparison util/matlab_midi/matrix2midi.m @ 81:a30e8bd6d948

matlab_midi scripts

+function midi=matrix2midi(M,ticks_per_quarter_note,timesig)
+% midi=matrix2midi(M,ticks_per_quarter_note)
+%
+% generates a midi matlab structure from a matrix
+%  specifying a list of notes.  The structure output
+%  can then be used by writemidi.m
+%
+% M: input matrix:
+%   1     2    3  4   5  6  
+%  [track chan nn vel t1 t2] (any more cols ignored...)
+%
+% optional arguments:
+% - ticks_per_quarter_note: integer (default 300)
+% - timesig: a vector of len 4 (default [4,2,24,8])
+%
+
+% Copyright (c) 2009 Ken Schutte
+% more info at: http://www.kenschutte.com/midi
+
+% TODO options:
+%  - note-off vs vel=0
+%  - tempo, ticks, etc
+
+if nargin < 2
+  ticks_per_quarter_note = 300;
+end
+
+if nargin < 3
+  timesig = [4,2,24,8];
+end
+
+tracks = unique(M(:,1));
+Ntracks = length(tracks);
+
+% start building 'midi' struct
+
+if (Ntracks==1)
+  midi.format = 0;
+else
+  midi.format = 1;
+end
+
+midi.ticks_per_quarter_note = ticks_per_quarter_note;
+
+tempo = 500000;   % could be set by user, etc...
+% (microsec per quarter note)
+
+for i=1:Ntracks
+  
+  trM = M(i==M(:,1),:);
+  
+  note_events_onoff = [];
+  note_events_n = [];
+  note_events_ticktime = [];
+ 
+  % gather all the notes:
+  for j=1:size(trM,1)
+    % note on event:
+    note_events_onoff(end+1)    = 1;
+    note_events_n(end+1)        = j;
+    note_events_ticktime(end+1) = 1e6 * trM(j,5) * ticks_per_quarter_note / tempo;
+    
+    % note off event:
+    note_events_onoff(end+1)    = 0;
+    note_events_n(end+1)        = j;
+    note_events_ticktime(end+1) = 1e6 * trM(j,6) * ticks_per_quarter_note / tempo;
+  end
+
+  
+  msgCtr = 1;
+  
+  % set tempo...
+  midi.track(i).messages(msgCtr).deltatime = 0;
+  midi.track(i).messages(msgCtr).type = 81;
+  midi.track(i).messages(msgCtr).midimeta = 0;
+  midi.track(i).messages(msgCtr).data = encode_int(tempo,3);
+  midi.track(i).messages(msgCtr).chan = [];
+  msgCtr = msgCtr + 1;
+  
+  % set time sig...
+  midi.track(i).messages(msgCtr).deltatime = 0;
+  midi.track(i).messages(msgCtr).type = 88;
+  midi.track(i).messages(msgCtr).midimeta = 0;
+  midi.track(i).messages(msgCtr).data = timesig(:);
+  midi.track(i).messages(msgCtr).chan = [];
+  msgCtr = msgCtr + 1;
+  
+  [junk,ord] = sort(note_events_ticktime);
+
+  prevtick = 0;
+  for j=1:length(ord)
+    
+    n = note_events_n(ord(j));
+    cumticks = note_events_ticktime(ord(j));
+    
+    midi.track(i).messages(msgCtr).deltatime = cumticks - prevtick;
+    midi.track(i).messages(msgCtr).midimeta = 1; 
+    midi.track(i).messages(msgCtr).chan = trM(n,2);
+    midi.track(i).messages(msgCtr).used_running_mode = 0;
+
+    if (note_events_onoff(ord(j))==1)
+      % note on:
+      midi.track(i).messages(msgCtr).type = 144;
+      midi.track(i).messages(msgCtr).data = [trM(n,3); trM(n,4)];
+    else
+      %-- note off msg:
+      %midi.track(i).messages(msgCtr).type = 128;
+      %midi.track(i).messages(msgCtr).data = [trM(n,3); trM(n,4)];
+      %-- note on vel=0:
+      midi.track(i).messages(msgCtr).type = 144;
+      midi.track(i).messages(msgCtr).data = [trM(n,3); 0];
+    end
+    msgCtr = msgCtr + 1;
+    
+    prevtick = cumticks;
+  end
+
+  % end of track:
+  midi.track(i).messages(msgCtr).deltatime = 0;
+  midi.track(i).messages(msgCtr).type = 47;
+  midi.track(i).messages(msgCtr).midimeta = 0;
+  midi.track(i).messages(msgCtr).data = [];
+  midi.track(i).messages(msgCtr).chan = [];
+  msgCtr = msgCtr + 1;
+  
+end
+
+
+% return a _column_ vector
+% (copied from writemidi.m)
+function A=encode_int(val,Nbytes)
+
+A = zeros(Nbytes,1);  %ensure col vector (diff from writemidi.m...)
+for i=1:Nbytes
+  A(i) = bitand(bitshift(val, -8*(Nbytes-i)), 255);
+end
+