/*
 * mvj - extract JPEG fields/frames from JPEG Quicktime movie (data untouched)
 *
 * mvj file.mv [trackno] frameno
 */
#include <bstring.h>
#include <string.h>
#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>
#include <dmedia/moviefile.h>

#define MVPR(s) fprintf(stderr, "%s: %s\n", s, mvGetErrorStr(mvGetErrno()))
#define EMV(func, s) if (func == DM_FAILURE) { MVPR(s); exit(1); }

char *prog;

static void
writefile(int n, int f, char *cp, size_t nb)
{
	char name[64];
	int fd;

	if (f) {
		sprintf(name, "%05d.%d.jpeg", n, f);
	} else {
		sprintf(name, "%05d.jpeg", n);
	}
	if ((fd = open(name, O_WRONLY|O_CREAT|O_TRUNC, 0644)) < 0) {
		perror(name);
		exit(1);
	}
printf("%s %d bytes\n", name, nb);
	if (write(fd, cp, nb) != nb) {
		perror(name);
		exit(1);
	}
	close(fd);
}

MVid movie, track;
double rate;
MVframe nframes, fr;
int index;
MVtime mvtime;
MVtime dur;
MVtimescale tscale; 


void
xframe(frameno)
{
        mvtime = (long long)frameno * dur;

        EMV(mvGetTrackDataIndexAtTime(track, mvtime, tscale, &index, &fr),
							"get track index");
	if (mvTrackDataHasFieldInfo(track, index)) {
		size_t nb1, nb2;
		char *buf1, *buf2;
		off64_t g;

		EMV(mvGetTrackDataFieldInfo(track, index, &nb1, &g, &nb2),
							"get field info");
		buf1 = malloc(nb1);
		buf2 = malloc(nb2);
		if (!buf1 || !buf2) {
			fprintf(stderr, "%s: malloc(%d,%d) failed\n",
				prog, nb1, nb2);
			exit(1);
		}
		EMV(mvReadTrackDataFields(track, index, nb1, buf1, nb2, buf2),
							"read field data");
		writefile(frameno, 1, buf1, nb1);
		writefile(frameno, 2, buf2, nb2);
	} else {
        	MVdatatype dt;
		size_t nb;
		char *buf;
		int p;

        	EMV(mvGetTrackDataInfo(track, index, &nb, &p, &dt, &fr),
						"get track info");
		if ((buf = malloc(nb)) == NULL) {
			fprintf(stderr, "%s: malloc failed\n", prog);
			exit(1);
		}
        	EMV(mvReadTrackData(track, index, nb, buf),
						"read track data");
		writefile(frameno, 0, buf, nb);
	}
}

main(int argc, char **argv)
{
	char *mvname = argv[1];
	int frameno, trackno;

	prog = argv[0];

	if (argc != 3 && argc != 4) {
		fprintf(stderr,
			"usage: %s file.mv [trackno] frameno|\'a\'\n", prog);
		exit(1);
	}
	trackno = argc == 4 ? atoi(argv[2]) : 0;
	if (argv[argc - 1][0] == 'a') {
		frameno = -1;
	} else {
		frameno = atoi(argv[argc - 1]);
	}

	EMV(mvOpenFile(mvname, O_RDONLY, &movie), mvname);
	if (mvGetFileFormat(movie) != MV_FORMAT_QT) {
		fprintf(stderr, "%s: %s is not Quicktime\n", prog, mvname);
		exit(1);
	}

	EMV(mvFindTrackByIndex(movie, trackno, &track), "find track N");
	if (mvGetTrackMedium(track) != DM_IMAGE) {
		fprintf(stderr, "%s: %s track %d is not DM_IMAGE\n",
			prog, mvname, trackno);
		exit(1);
	}
	if (strcmp(mvGetImageCompression(track), "JPEG") != 0) {
		fprintf(stderr, "%s: %s track %d is not JPEG\n",
			prog, mvname, trackno);
		exit(1);
	}
	nframes = mvGetTrackLength(track);

	tscale = mvGetMovieTimeScale(movie);
	rate = mvGetImageRate(track);
	dur = (long long)((double)tscale/rate);
	if (frameno == -1) {
		for (frameno = 0; frameno < nframes; frameno++) {
			xframe(frameno);
		}

	} else {
        	if (frameno < 0 || frameno >= nframes) {
			fprintf(stderr, "%s: %s has %d frames\n",
				prog, mvname, nframes);
			exit(1);
		}
		xframe(frameno);
	}
}