ivan@81: function rawbytes=writemidi(midi,filename,do_run_mode)
ivan@81: % rawbytes=writemidi(midi,filename,do_run_mode)
ivan@81: %
ivan@81: % writes to a midi file
ivan@81: %
ivan@81: % midi is a structure like that created by readmidi.m
ivan@81: %
ivan@81: % do_run_mode: flag - use running mode when possible.
ivan@81: %    if given, will override the msg.used_running_mode
ivan@81: %    default==0.  (1 may not work...)
ivan@81: %
ivan@81: % TODO: use note-on for note-off... (for other function...)
ivan@81: %
ivan@81: 
ivan@81: % Copyright (c) 2009 Ken Schutte
ivan@81: % more info at: http://www.kenschutte.com/midi
ivan@81: 
ivan@81: 
ivan@81: %if (nargin<3)
ivan@81: do_run_mode = 0;
ivan@81: %end
ivan@81: 
ivan@81: 
ivan@81: % do each track:
ivan@81: Ntracks = length(midi.track);
ivan@81: 
ivan@81: for i=1:Ntracks
ivan@81: 
ivan@81:   databytes_track{i} = [];
ivan@81:   
ivan@81:   for j=1:length(midi.track(i).messages)
ivan@81: 
ivan@81:     msg = midi.track(i).messages(j);
ivan@81: 
ivan@81:     msg_bytes = encode_var_length(msg.deltatime);
ivan@81: 
ivan@81:     if (msg.midimeta==1)
ivan@81: 
ivan@81:       % check for doing running mode
ivan@81:       run_mode = 0;
ivan@81:       run_mode = msg.used_running_mode;
ivan@81:       
ivan@81:       % should check that prev msg has same type to allow run
ivan@81:       % mode...
ivan@81:       
ivan@81:       
ivan@81:       %      if (j>1 && do_run_mode && msg.type == midi.track(i).messages(j-1).type)
ivan@81: %	run_mode = 1;
ivan@81: %      end
ivan@81: 
ivan@81: 
ivan@81: msg_bytes = [msg_bytes; encode_midi_msg(msg, run_mode)];
ivan@81:     
ivan@81:     
ivan@81:     else
ivan@81:       
ivan@81:       msg_bytes = [msg_bytes; encode_meta_msg(msg)];
ivan@81:       
ivan@81:     end
ivan@81: 
ivan@81: %    disp(msg_bytes')
ivan@81: 
ivan@81: %if (msg_bytes ~= msg.rawbytes)
ivan@81: %  error('rawbytes mismatch');
ivan@81: %end
ivan@81: 
ivan@81:     databytes_track{i} = [databytes_track{i}; msg_bytes];
ivan@81:     
ivan@81:   end
ivan@81: end 
ivan@81: 
ivan@81: 
ivan@81: % HEADER
ivan@81: % double('MThd') = [77 84 104 100]
ivan@81: rawbytes = [77 84 104 100 ...
ivan@81: 	    0 0 0 6 ...
ivan@81: 	    encode_int(midi.format,2) ...
ivan@81: 	    encode_int(Ntracks,2) ...
ivan@81: 	    encode_int(midi.ticks_per_quarter_note,2) ...
ivan@81: 	   ]';
ivan@81: 
ivan@81: % TRACK_CHUCKS
ivan@81: for i=1:Ntracks
ivan@81:   a = length(databytes_track{i});
ivan@81:   % double('MTrk') = [77 84 114 107]
ivan@81:   tmp = [77 84 114 107 ...
ivan@81: 	 encode_int(length(databytes_track{i}),4) ...
ivan@81: 	 databytes_track{i}']';
ivan@81:   rawbytes(end+1:end+length(tmp)) = tmp;
ivan@81: end
ivan@81: 
ivan@81: 
ivan@81: % write to file
ivan@81: fid = fopen(filename,'w');
ivan@81: %fwrite(fid,rawbytes,'char');
ivan@81: fwrite(fid,rawbytes,'uint8');
ivan@81: fclose(fid);
ivan@81: 
ivan@81: % return a _column_ vector
ivan@81: function A=encode_int(val,Nbytes)
ivan@81: 
ivan@81: for i=1:Nbytes
ivan@81:   A(i) = bitand(bitshift(val, -8*(Nbytes-i)), 255);
ivan@81: end
ivan@81: 
ivan@81: 
ivan@81: function bytes=encode_var_length(val)
ivan@81: 
ivan@81: binStr = dec2base(round(val),2);
ivan@81: Nbytes = ceil(length(binStr)/7);
ivan@81: 
ivan@81: binStr = ['00000000' binStr];
ivan@81: bytes = [];
ivan@81: for i=1:Nbytes
ivan@81:   if (i==1)
ivan@81:     lastbit = '0';
ivan@81:   else
ivan@81:     lastbit = '1';
ivan@81:   end
ivan@81:   B = bin2dec([lastbit binStr(end-i*7+1:end-(i-1)*7)]);
ivan@81:   bytes = [B; bytes];
ivan@81: end
ivan@81: 
ivan@81: 
ivan@81: function bytes=encode_midi_msg(msg, run_mode)
ivan@81: 
ivan@81: bytes = [];
ivan@81: 
ivan@81: if (run_mode ~= 1)
ivan@81:   bytes = msg.type;
ivan@81:   % channel:
ivan@81:   bytes = bytes + msg.chan;  % lower nibble should be chan
ivan@81: end
ivan@81: 
ivan@81: bytes = [bytes; msg.data];
ivan@81: 
ivan@81: function bytes=encode_meta_msg(msg)
ivan@81: 
ivan@81: bytes = 255;
ivan@81: bytes = [bytes; msg.type];
ivan@81: bytes = [bytes; encode_var_length(length(msg.data))];
ivan@81: bytes = [bytes; msg.data];
ivan@81: