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/************************************************************************
* seq2mid.c - converts dump of /dev/sequencer (aka toy.c ouput) to a
* type 0 midi file.
*
* This code was written by by Nathan Laredo (laredo@gnu.ai.mit.edu)
* Source code may be freely distributed in unmodified form.
*************************************************************************/
#include <stdio.h>
#include <fcntl.h>
#include <unistd.h>
#include <stdlib.h>
#include <sys/soundcard.h>
int outfile, infile;
/*
* midi header, track header, and timing info. Given timing is good for
* /dev/sequencer tick of 100Hz. Adjust division for others.
*/
#define FLUFFSIZE 29
unsigned char midifluff[FLUFFSIZE] =
{ 0x4d, 0x54, 0x68, 0x64, /* MThd */
0x00, 0x00, 0x00, 0x06, /* 6 bytes in header block */
0x00, 0x00, /* midi format 0 */
0x00, 0x01, /* one track */
/* the following line is for a 100Hz sequencer tick, adjust accordingly */
0x00, 0x32, /* 50 ticks per quarter, 100Hz resolution */
0x4d, 0x54, 0x72, 0x6b, /* MTrk */
#define SIZEINDEX 18
0x00, 0x00, 0x00, 0x00, /* x bytes in track block */
0x00, 0xff, 0x51, 0x03, /* meta tempo event */
0x07, 0xA1, 0x20 /* one quarter note = .5 sec = 120bpm */
#define STARTCOUNT 7
};
#define ENDFLUFFSIZE 4
unsigned char endfluff[ENDFLUFFSIZE] =
{ 0x00, 0xff, 0x2f, 0x00 }; /* meta end of track */
/* indexed by high nibble of command */
int cmdlen[16] =
{0, 0, 0, 0, 0, 0, 0, 0, 2, 2, 2, 2, 1, 1, 2, 0};
void midiwrite(buf, count)
unsigned char *buf;
int count;
{
if(write(outfile, buf, count) < count) {
perror("write");
exit(-1);
}
}
int main(argc, argv)
int argc;
char **argv;
{
unsigned char delta[4], inputbuf[5], mid[8], cmd = 0;
unsigned int oldticks = 0, ticks = 0, db = 0;
off_t filesize, tracksize;
int i, status = 0;
if (argc < 3) {
fprintf(stderr, "usage: %s infile.seq outfile.mid\n", argv[0]);
exit(1);
}
if ((infile = open(argv[1], O_RDONLY, 0)) < 0) {
perror(argv[1]);
exit(-1);
}
if ((outfile = open(argv[2], O_WRONLY | O_CREAT | O_TRUNC, 0666))
< 0) {
perror(argv[2]);
exit(-1);
}
midiwrite(midifluff, FLUFFSIZE);
inputbuf[4] = 0;
while (read(infile, inputbuf, 4) == 4) {
if (inputbuf[0] == SEQ_WAIT)
ticks = (*(unsigned int *) &inputbuf[1]);
if (*inputbuf == SEQ_MIDIPUTC) {
if (inputbuf[1] & 0x80)
cmd = mid[db = 0] = inputbuf[1];
else
mid[db] = inputbuf[1];
db++;
if (db == cmdlen[cmd >> 4] + 1) {
register unsigned int buffer = ticks - oldticks;
delta[i = 3] = (buffer & 0x7f);
while ((buffer >>= 7) > 0 && i > 0)
delta[--i] = (buffer & 0x7f) | 0x80;
midiwrite(&delta[i], 4 - i);
if (status == cmd && cmd < 0xf0)
midiwrite(&mid[1], db - 1);
else
midiwrite(mid, db);
status = mid[0];
oldticks = ticks;
db = 1;
}
}
}
midiwrite(endfluff, ENDFLUFFSIZE);
/* write big endian track size */
filesize = lseek(outfile, 0, SEEK_CUR);
tracksize = filesize - FLUFFSIZE + STARTCOUNT;
lseek(outfile, SIZEINDEX, SEEK_SET);
delta[0] = (tracksize >> 24) & 0xff;
delta[1] = (tracksize >> 16) & 0xff;
delta[2] = (tracksize >> 8) & 0xff;
delta[3] = tracksize & 0xff;
midiwrite(delta, 4);
close(infile);
close(outfile);
printf("%s: saved as %s, %d bytes, %d bytes track data\n",
argv[1], argv[2], (int) filesize, (int) tracksize);
exit(0);
}
/* end of file */
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