Here is the code (subroutine) i used to decode Midi blocks and made them available on karaoke.vietbel.org
It's in perl and convert midi block to Midi Track in T2MF format. My solution is a hybrid one, it requires several program including the lyric inserting .So I think that the most important code is how to decode the midi block. You can easily write it again in C directly under Midi standard.
For each midi block
$delay =0;
for ( $j=0; $j < $midi_size -5 ; $j+=5) {
$midi_block=unpack("H*",substr($midi_part,$j,5));
$midi_delay=unpack("C",substr($midi_part,$j,1));
$midi_delay_next=unpack("C",substr($midi_part,$j+5,1));
$delay+= $midi_delay;
$midi_delay2=substr($midi_part,$j+1,1);
$midi_event=substr($midi_part,$j+2,1);
$midi_channel= ord($midi_event) & 0x0f ;
#$midi_channel= ord($midi_event);
$midi_channel+= 1;
$midi_evnt = ord($midi_event) & 0xf0;
$midi_note=ord(substr($midi_part,$j+3,1));
$midi_velocity=ord(substr($midi_part,$j+4,1));
# 192 0xC0 176 0xB0
if ( $midi_evnt == "192" ) { # 0xC0 PrCh
printf FILEOUT ("%.6d PrCh ch=$midi_channel p=$midi_note\n",$delay);
}
elsif ( $midi_evnt == "176" ) { # 0xb0 Par
printf FILEOUT ("%.6d Par ch=$midi_channel c=$midi_note v=$midi_velocity\n",$delay);
}
elsif ( $midi_evnt == "208" ) { # 0xd0 ChPr Channel Pressure
$bend= ($midi_velocity*128)+ $midi_note;
printf FILEOUT ("%.6d ChPr ch=$midi_channel v=$bend\n",$delay);
}
elsif ( $midi_evnt == "224" ) { # 0xe0 Pitch Bend
$bend= ($midi_velocity*128)+ $midi_note;
printf FILEOUT ("%.6d Pb ch=$midi_channel v=$bend\n",$delay);
}
elsif ( $midi_evnt == "160" ) { # OxA0
printf FILEOUT ("%.6d PoPr ch=$midi_channel n=$midi_note v=$midi_velocity\n",$delay);
if ( ord($midi_delay2) > 0x00) {
#delay1=$delay + ord($midi_delay2);
$delay1 =$delay + $midi_delay_next + ord($midi_delay2);
printf FILEOUT ("%.6d PoPr ch=$midi_channel n=$midi_note v=0\n",$delay1);
}
}
elsif ( $midi_evnt == "0" ) { # 0xe0 Pitch Bend
printf FILEOUT ("%.6d On ch=$midi_channel n=$midi_note v=$midi_velocity\n",$delay);
if ( ord($midi_delay2) > 0x00) {
#delay1=$delay + ord($midi_delay2);
$delay1 =$delay + $midi_delay_next + ord($midi_delay2);
printf FILEOUT ("%.6d On ch=$midi_channel n=$midi_note v=0\n",$delay1);
}
}
else {
printf FILE_EVT ("MIDI EVENT=%s ",$midi_block);
printf FILE_EVT ("%.6d UNKNOWN $midi_evnt\n",$delay);
}
}
printf FILE_DEBUG ("MIDI EVENT=%s\n",$midi_block);
close FILEOUT;
BE CAREFUL :
You must sort again the line in order to synchronize On ad Off in the chronological tick!
# Sort delay
open(FILEIN,"<$file_name") || die "cannot open file";
@DATA=<FILEIN>;
close(FILEIN);
foreach (@DATA) {
($delay,$rest) = split; # get score
$delay{$_} = $delay; # record it
}
@DATA = sort {
$delay{$a} <=> $delay{$b};
} @DATA;
# Wirte the @DATA again and you obtain the Midi Track in T2MF/MF2T format
Hope it will complete your MIDI function.
Some comments :
#0 PrCh ch=1 p=17 00 ff c0 11 ff if 3rd byte = c0
# 00 2e c0 18 ff 2e :??? (NGAN CACH)
# Program change: PrCh[ProgCh] <ch> <prog>
# TODO why ff 2e ???ff is the identifer of this event!!
#0 Par ch=1 c=7 v=90 00 01 b0 07 5a if 3rd byte = b0
#Delay 144 On ch=2 n=31 v=100 90 08 01 1f 64 --- 08 is another evt when
# velocity is 0
# Because the 3rd byte is used 0x0f for channel number
# To identify the event 3rd byte 0xf0
# c = PrCh
# b = Par
# e = Pitch Bend xx yy yy*128+xx
# 0 else is channel (16 channels ???)
# 1 ???????? TODO
# Pitch Bend Pb ch=4
# "ChPr": -- 0x0D = ChannelPressure
# do(msg[3]) -- chan
# do(msg[4]) -- val
# return chr(208+ch-1)&chr(v)--0xD0
# "PoPr": -- 0x0A = PolyPressure
# do(msg[3]) -- chan
# do(msg[4]) -- note
# do(msg[5]) -- val
# return chr(160+ch-1)&chr(n)&chr(v)--0xA0
Locked
