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/*
* Copyright (C) 2001 Kawamata/Hitoshi <hitoshi.kawamata@nifty.ne.jp>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#include <config.h>
#include <stdlib.h>
#include "mpegtimecode.h"
/**************************************************************
* // NTSC DROP FRAME TIMECODE / 29.97fps (SMTPE)
* // hh:mm:ss:ff
* // hh: 0..
* // mm: 0..59
* // ss: 0..59
* // ff: 0..29 # ss != 0 || mm % 10 == 0
* // 2..29 # ss == 0 && mm % 10 != 0
* //
* // 00:00:00:00 00:00:00:01 00:00:00:02 ... 00:00:00:29
* // 00:00:01:00 00:00:01:01 00:00:01:02 ... 00:00:01:29
* // :
* // 00:00:59:00 00:00:59:01 00:00:59:02 ... 00:00:59:29
* // 00:01:00:02 ... 00:01:00:29
* // 00:01:01:00 00:01:01:01 00:01:01:02 ... 00:01:00:29
* // :
* // 00:01:59:00 00:01:59:01 00:01:59:02 ... 00:01:59:29
* // 00:02:00:02 ... 00:02:00:29
* // 00:02:01:00 00:02:01:01 00:02:01:02 ... 00:02:00:29
* // :
* // :
* // 00:09:59:00 00:09:59:01 00:09:59:02 ... 00:09:59:29
* // 00:10:00:00 00:10:00:01 00:10:00:02 ... 00:10:00:29
* // 00:10:01:00 00:10:01:01 00:10:01:02 ... 00:10:01:29
* // :
* // 00:10:59:00 00:10:59:01 00:10:59:02 ... 00:10:59:29
* // 00:11:00:02 ... 00:11:00:29
* // 00:11:01:00 00:11:01:01 00:11:01:02 ... 00:11:00:29
* // :
* // :
* // DROP FRAME / 59.94fps (no any standard)
* // DROP FRAME / 23.976fps (no any standard)
***************************************************************/
int dropframetimecode = -1;
/* mpeg_timecode() return -tc->f on first frame in the minute, tc->f on other. */
int
mpeg_timecode(MPEG_timecode_t *tc, int f, int fpscode, double fps)
{
static const int ifpss[] = { 0, 24, 24, 25, 30, 30, 50, 60, 60, };
int h, m, s;
if (dropframetimecode < 0) {
char *env = getenv("MJPEG_DROP_FRAME_TIME_CODE");
dropframetimecode = (env && *env != '0' && *env != 'n' && *env != 'N');
}
if (dropframetimecode &&
0 < fpscode && fpscode + 1 < sizeof ifpss / sizeof ifpss[0] &&
ifpss[fpscode] == ifpss[fpscode + 1]) {
int topinmin = 0, k = (30*4) / ifpss[fpscode];
f *= k; /* frame# when 119.88fps */
h = (f / ((10*60*30-18)*4)); /* # of 10min. */
f %= ((10*60*30-18)*4); /* frame# in 10min. */
f -= (2*4); /* frame# in 10min. - (2*4) */
m = (f / ((60*30-2)*4)); /* min. in 10min. */
topinmin = ((f - k) / ((60*30-2)*4) < m);
m += (h % 6 * 10); /* min. */
h /= 6; /* hour */
f %= ((60*30-2)*4); /* frame# in min. - (2*4)*/
f += (2*4); /* frame# in min. */
s = f / (30*4); /* sec. */
f %= (30*4); /* frame# in sec. */
f /= k; /* frame# in sec. on original fps */
tc->f = f;
if (topinmin)
f = -f;
} else {
int ifps = ((0 < fpscode && fpscode < sizeof ifpss / sizeof ifpss[0])?
ifpss[fpscode]: (int)(fps + .5));
s = f / ifps;
f %= ifps;
m = s / 60;
s %= 60;
h = m / 60;
m %= 60;
tc->f = f;
}
tc->s = s;
tc->m = m;
tc->h = h;
return f;
}
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