%%
%% MIDI Synthesizer
%%
%% (c) 2007 Kenneth Adams Jr.
%% Georgia Institute of Technology, Atlanta, GA
%%
%% For CS 1371, Prof. Stallworth, C.
%%
%% A fully functional MIDI synthesizer, supporting 128 instruments and one
%% drum track. It also supports the volume and expression MIDI
%% controllers.
%%
%% Instrument samples for this synthesizer were extracted with
%% another MATLAB script from the Roland SoundSet DLS file packaged with
%% most versions of Windows located in %SYSTEM32%\drivers\gm.dls
function [song freq] = readmidi2(midiFile)
% clc
global GAME_PATH; % Stellaria Game Directories
freq = 22050;
sndDir = GAME_PATH.UTIL_MIDI_SOUND;
runVis = false;
fftSize = floor(freq * .05);
counter = 0;
% otherMIDI = readmidi3([midiFile]);
% [otherNOTE otherENDTIME] = midiInfo(otherMIDI, freq);
% [otherTempos, otherTempos_time] = getTempoChanges(otherMIDI);
fprintf('+------------------------------+\n');
fprintf('| |\n');
fprintf('| MIDI Synthesizer |\n');
fprintf('| c2007 Kenneth Adams |\n');
fprintf('| |\n');
fprintf('+------------------------------+\n\n');
% Read wav table - preparsed from dlsparser.m
sndTbl = dlmread('sound.tbl', '\t');
instr(129).note(1).root = 0;
for (i = [1 : length(sndTbl)])
r = sndTbl(i, :);
if (r(2) == 0)
% Melodic Instrument
instr(r(1) + 1).note(end + 1).root = r(3);
instr(r(1) + 1).note(end).low = r(4);
instr(r(1) + 1).note(end).hi = r(5);
instr(r(1) + 1).note(end).idx = r(6);
instr(r(1) + 1).note(end).loopStart = r(7);
instr(r(1) + 1).note(end).loopLen = r(8);
instr(r(1) + 1).note(end).data = [];
elseif (r(1) == 0)
% Drum Kit
instr(129).note(end + 1).root = r(4);
instr(129).note(end).low = -1;
instr(129).note(end).hi = -1;
instr(129).note(end).idx = r(6);
instr(129).note(end).loopStart = r(7);
instr(129).note(end).loopLen = r(8);
instr(129).note(end).data = [];
end
end
fprintf('** Loading MIDI file: %s\n', midiFile);
fh = fopen(midiFile, 'r');
%% Read in header data
midiId = fread(fh, 8, 'uint8');
if (midiId(1 : 5) ~= [77; 84; 104; 100; 6])
error('Invalid file header.')
end
in = fread(fh, 3, 'uint16', 'ieee-be');
midiType = in(1);
midiTracks = in(2);
midiTime = in(3);
if (midiTime > 32767)
error('Unsupported time division.');
end
tempo = 120;
song = zeros(300 * freq, 1);
% Process each track.
for (track = [1 : midiTracks])
trackId = fread(fh, 4, 'uint8');
% Verify that the file points to a valid track.
if (trackId ~= [77; 84; 114; 107])
error('Invalid track header.')
end
trackLen = fread(fh, 1, 'uint32', 'ieee-be');
trackData = fread(fh, trackLen, 'uint8');
trackPtr = 1;
lastMsgType = 0;
% fprintf('[TRACK] i=%d len=%d\n', track, trackLen);
trackNotes = [];
trackTime = 0;
trackExpr = ones(1, 16);
trackVol = ones(1, 16);
trackPan = ones(1, 16) .* .5;
instrMap = ones(1, 16);
loadTimer = [0 0 0 0 0 0];
while (trackPtr < trackLen)
if (etime(clock(), loadTimer) > 1)
loadTimer = clock();
fprintf('** Loading track %2d/%2d : %4.1f%%\n', track, midiTracks, ...
100 * trackPtr / trackLen);
end
msgTime = readVarLen();
msgType = readTrack(1);
% msgType should ALWAYS have high bit set, if not, the msgType
% comes from the last message. A bunch of MIDI files use this
% as a form of compression.
if (msgType < 128)
msgType = lastMsgType;
% msgType is actually the byte ahead of the type, easiest
% way to handle this is to back up the read ptr.
trackPtr = trackPtr - 1;
end
%% MetaEvents have status byte 0xFF.
if (msgType == 255)
msgMeta = readTrack(1);
msgLen = readVarLen();
msgData = readTrack(msgLen);
switch (msgMeta)
case {1, 2, 3, 4, 5}
% Text information
% fprintf('*** Info: %s\n', char(msgData));
case 47
% End of track
break
case 81
% Tempo set
tempo = round(60000000 / (2 ^ 16 * msgData(1) + ...
2 ^ 8 * msgData(2) + msgData(3)));
end
% fprintf('[METAMSG] type=%d len=%d\n', msgMeta, msgLen);
% if msgMeta == 81
% fprintf('tempo = %.4f, trackPtr = %d\n', tempo, trackPtr);
% end
else
lastMsgType = msgType;
msgChannel = mod(msgType, 16) + 1;
msgType = floor(msgType / 16);
trackTime = trackTime + msgTime / midiTime;
if (msgType == 12 || msgType == 13)
msgParams = readTrack(1);
% fprintf('[MSG] dt=%d type=%d chan=%d p0=%d\n', ...
% msgTime, msgType, msgChannel, msgParams(1));
else
msgParams = readTrack(2);
% fprintf('[MSG] dt=%d type=%d chan=%d p0=%d p1=%d\n',...
% msgTime, msgType, msgChannel, msgParams(1), msgParams(2));
end
if (msgType == 8 || (msgType == 9 && msgParams(2) == 0))
% End the note on the same channel and note number.
for (i = [1 : length(trackNotes)])
if (trackNotes(i).channel == msgChannel && ...
trackNotes(i).note == msgParams(1))
noteStart = trackNotes(i).time;
vol = trackVol(msgChannel) * ...
trackExpr(msgChannel) * ...
trackNotes(i).note;
% volLeft = vol * (1 - trackPan(msgChannel));
% volRight = vol * trackPan(msgChannel);
%% Add note to song data.
if (msgChannel == 10)
if (msgParams(1) < 82)
id = 129;
addSample(inf, msgParams(1));
end
else
id = instrMap(msgChannel);
addSample(trackTime, msgParams(1));
end
counter = counter + 1;
trackNotes(i) = [];
break
end
end
elseif (msgType == 9)
% Begin a note
i = 1 + length(trackNotes);
trackNotes(i).channel = msgChannel;
trackNotes(i).note = msgParams(1);
trackNotes(i).time = trackTime;
trackNotes(i).vol = msgParams(2);
elseif (msgType == 11)
% MIDI Controller
if (msgParams(1) == 7)
trackVol(msgChannel) = msgParams(2) / 127;
% fprintf('[VOL] chan=%d vol=%d\n', msgChannel, msgParams(2));
elseif (msgParams(1) == 10)
trackPan(msgChannel) = msgParams(2) / 127;
elseif (msgParams(1) == 11)
trackExpr(msgChannel) = msgParams(2) / 127;
% fprintf('[EXPR] \n');
end
elseif (msgType == 12)
% Change the instrument map.
instrMap(msgChannel) = msgParams(1) + 1;
% fprintf('[MAP] chan=%d instr=%d\n', msgChannel, msgParams(1) + 1);
end
end
end
% fprintf('COUNTER = %d\n', counter);
counter = 0;
end
% Remove blanks at end of song and normalize to +/- 1.0
song(find(song ~= 0, 1, 'last') + 1: end) = [];
song = song / (max(song) .* 2);
fclose(fh);
% Play the song.
% TODO: Cache file as .wav ?
clear instr;
songTime = floor(length(song) / freq);
% fprintf('** Playing: %d m %d s\n', floor(songTime / 60), mod(songTime, 60));
% wavplay(song, freq, 'async');
% Because wavplay in sync mode maxes CPU!
% pause(songTime);
% if (runVis)
% fprintf('** Starting visualizer...\n');
% df = 1 / songTime;
% fftPos = 0;
%
% visTimer = timer( ...
% 'TimerFcn', @visCallback, ...
% 'Period', round(1000 * fftSize / freq) / 1000, ...
% 'ExecutionMode', 'fixedRate');
%
% visCallbackLock = false;
% start(visTimer);
% pause(songTime + 2);
% stop(visTimer);
% close all;
% end
%% Get a variable length value from the track
function val = readVarLen()
val = 0;
loop = true;
while (loop)
val = val * 128 + mod(trackData(trackPtr), 128);
loop = (trackData(trackPtr) > 127);
trackPtr = trackPtr + 1;
end
end
%% Get x bytes from the track.
function val = readTrack(x)
% if (trackPtr + x - 1 > length(trackData))
% error('Track data read error.');
% end
val = trackData(trackPtr : trackPtr + x - 1);
trackPtr = trackPtr + x;
end
%% Insert a sample into the song.
function addSample(noteEnd, note)
z = [];
for (j = [1 : length(instr(id).note)])
k = instr(id).note(j);
if (k.root == note)
z = k;
if (isempty(z.data))
z.data = wavread([sndDir num2str(z.idx + 1) '.wav']);
instr(id).note(j) = z;
end
break;
end
end
if (isempty(z))
for (j = [1 : length(instr(id).note)])
k = instr(id).note(j);
if (k.low <= note & note <= k.hi)
z = k;
shift = (2 ^ (1 / 12)) ^ (note - z.root);
if (isempty(z.data))
% num2str(z.idx + 1)
z.data = wavread([sndDir num2str(z.idx + 1) '.wav']);
end
n = length(z.data);
z.root = note;
z.data = z.data(round(linspace(1, n, n / shift)));
z.loopStart = floor(z.loopStart / shift);
z.loopLen = floor(z.loopLen / shift);
z.low = -1;
z.hi = -1;
instr(id).note(end + 1) = z;
break;
end
end
end
% Happens if the note data wasn't found, shouldn't happen.
if (~isstruct(z))
return
end
% Adjust midi ticks to index in sound array.
j = floor(1 + noteStart * 60 * freq / tempo);
k = floor(1 + noteEnd * 60 * freq / tempo);
if (z.loopStart > 0 & z.loopLen > 0)
loopSnd = [];
loopEnd = z.loopStart + z.loopLen - 1;
% Repeat the looping section
% There is a 2 second hard limit, in case of a "stuck note."
% These notes actually are not stuck, they probably just don't
% have a decay applied to it yet.
while (length(loopSnd) < (k - j) && length(loopSnd) < 2 * freq)
loopSnd = [loopSnd; z.data(z.loopStart : loopEnd, :)];
end
snd = [z.data(1 : z.loopStart); loopSnd; z.data(loopEnd : end)];
% Apply decay for sustain portion of note.
if (any(id == [1 : 16, 113 : 119, 129]))
n = length(snd(z.loopStart : end));
snd(z.loopStart : end) = snd(z.loopStart : end) .* ...
linspace(1, 0, n)' .^ 2;
end
else
snd = z.data;
end
n = length(snd);
if (n + j > length(song))
song(n + j + 30 * freq, 1) = 0;
end
% Combine song and sample
song(j : n + j - 1, 1) = song(j : n + j - 1, 1) + vol .* snd;
end
function visCallback(varargin)
fftPos = fftPos + 1;
if (visCallbackLock)
return
end
visCallbackLock = true;
fftStart = fftPos * fftSize + 1;
fftEnd = fftStart + fftSize - 1;
if (fftEnd > length(song))
return
end
y = abs(fft(song(fftStart : fftEnd)))';
subplot(2, 1, 1);
plot((1 : fftSize) .* df, y, '.');
% axis off
axis([0, df * fftSize * .5, 0, 100]);
%
subplot(2, 1, 2);
plot(song(fftStart : fftEnd), 'r')
% hold on
% plot([0 fftSize], [0 0], 'm');
% axis off
axis([0, fftSize, -.5, .5]);
visCallbackLock = false;
end
end
