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livetrax/libs/libltc/timecode.c

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/*
libltc - en+decode linear timecode
Copyright (C) 2006-2012 Robin Gareus <robin@gareus.org>
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU Lesser General Public License as
published by the Free Software Foundation, either version 3 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 Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with this library.
If not, see <http://www.gnu.org/licenses/>.
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "ltc/ltc.h"
#ifdef HAVE_CONFIG_H
# include <config.h>
#endif
/**
* SMPTE Timezones
*/
struct SMPTETimeZonesStruct {
unsigned char code; //actually 6 bit!
char timezone[6];
};
/**
* SMPTE Timezone codes as per http://www.barney-wol.net/time/timecode.html
*/
static const struct SMPTETimeZonesStruct smpte_time_zones[] =
{
/* code, timezone (UTC+) //Standard time //Daylight saving */
{ 0x00, "+0000" /* Greenwich */ /* - */ },
{ 0x00, "-0000" /* Greenwich */ /* - */ },
{ 0x01, "-0100" /* Azores */ /* - */ },
{ 0x02, "-0200" /* Mid-Atlantic */ /* - */ },
{ 0x03, "-0300" /* Buenos Aires */ /* Halifax */ },
{ 0x04, "-0400" /* Halifax */ /* New York */ },
{ 0x05, "-0500" /* New York */ /* Chicago */ },
{ 0x06, "-0600" /* Chicago Denver */ /* - */ },
{ 0x07, "-0700" /* Denver */ /* Los Angeles */ },
{ 0x08, "-0800" /* Los Angeles */ /* - */ },
{ 0x09, "-0900" /* Alaska */ /* - */ },
{ 0x10, "-1000" /* Hawaii */ /* - */ },
{ 0x11, "-1100" /* Midway Island */ /* - */ },
{ 0x12, "-1200" /* Kwaialein */ /* - */ },
{ 0x13, "+1300" /* - */ /* New Zealand */ },
{ 0x14, "+1200" /* New Zealand */ /* - */ },
{ 0x15, "+1100" /* Solomon Islands */ /* - */ },
{ 0x16, "+1000" /* Guam */ /* - */ },
{ 0x17, "+0900" /* Tokyo */ /* - */ },
{ 0x18, "+0800" /* Beijing */ /* - */ },
{ 0x19, "+0700" /* Bangkok */ /* - */ },
{ 0x20, "+0600" /* Dhaka */ /* - */ },
{ 0x21, "+0500" /* Islamabad */ /* - */ },
{ 0x22, "+0400" /* Abu Dhabi */ /* - */ },
{ 0x23, "+0300" /* Moscow */ /* - */ },
{ 0x24, "+0200" /* Eastern Europe */ /* - */ },
{ 0x25, "+0100" /* Central Europe */ /* - */ },
/* { 0x26, "Undefined" Reserved; do not use },*/
/* { 0x27, "Undefined" Reserved; do not use },*/
{ 0x28, "TP-03" /* Time precision class 3 */ /* - */ },
{ 0x29, "TP-02" /* Time precision class 2 */ /* - */ },
{ 0x30, "TP-01" /* Time precision class 1 */ /* - */ },
{ 0x31, "TP-00" /* Time precision class 0 */ /* - */ },
{ 0x0A, "-0030" /* - */ /* - */ },
{ 0x0B, "-0130" /* - */ /* - */ },
{ 0x0C, "-0230" /* - */ /* Newfoundland */ },
{ 0x0D, "-0330" /* Newfoundland */ /* - */ },
{ 0x0E, "-0430" /* - */ /* - */ },
{ 0x0F, "-0530" /* - */ /* - */ },
{ 0x1A, "-0630" /* - */ /* - */ },
{ 0x1B, "-0730" /* - */ /* - */ },
{ 0x1C, "-0830" /* - */ /* - */ },
{ 0x1D, "-0930" /* Marquesa Islands */ /* - */ },
{ 0x1E, "-1030" /* - */ /* - */ },
{ 0x1F, "-1130" /* - */ /* - */ },
{ 0x2A, "+1130" /* Norfolk Island */ /* - */ },
{ 0x2B, "+1030" /* Lord Howe Is. */ /* - */ },
{ 0x2C, "+0930" /* Darwin */ /* - */ },
{ 0x2D, "+0830" /* - */ /* - */ },
{ 0x2E, "+0730" /* - */ /* - */ },
{ 0x2F, "+0630" /* Rangoon */ /* - */ },
{ 0x3A, "+0530" /* Bombay */ /* - */ },
{ 0x3B, "+0430" /* Kabul */ /* - */ },
{ 0x3C, "+0330" /* Tehran */ /* - */ },
{ 0x3D, "+0230" /* - */ /* - */ },
{ 0x3E, "+0130" /* - */ /* - */ },
{ 0x3F, "+0030" /* - */ /* - */ },
{ 0x32, "+1245" /* Chatham Island */ /* - */ },
/* { 0x33, "Undefined" Reserved; do not use },*/
/* { 0x34, "Undefined" Reserved; do not use },*/
/* { 0x35, "Undefined" Reserved; do not use },*/
/* { 0x36, "Undefined" Reserved; do not use },*/
/* { 0x37, "Undefined" Reserved; do not use },*/
{ 0x38, "+XXXX" /* User defined time offset */ /* - */ },
/* { 0x39, "Undefined" Unknown Unknown },*/
/* { 0x39, "Undefined" Unknown Unknown },*/
{ 0xFF, "" /* The End */ }
};
static void smpte_set_timezone_string(LTCFrame *frame, SMPTETimecode *stime) {
int i = 0;
const unsigned char code = frame->user7 + (frame->user8 << 4);
char timezone[6] = "+0000";
for (i = 0 ; smpte_time_zones[i].code != 0xFF ; i++) {
if ( smpte_time_zones[i].code == code ) {
strcpy(timezone, smpte_time_zones[i].timezone);
break;
}
}
strcpy(stime->timezone, timezone);
}
static void smpte_set_timezone_code(SMPTETimecode *stime, LTCFrame *frame) {
int i = 0;
unsigned char code = 0x00;
// Find code for timezone string
// Primitive search
for (i=0; smpte_time_zones[i].code != 0xFF; i++) {
if ( (strcmp(smpte_time_zones[i].timezone, stime->timezone)) == 0 ) {
code = smpte_time_zones[i].code;
break;
}
}
frame->user7 = code & 0x0F;
frame->user8 = (code & 0xF0) >> 4;
}
/** Drop-frame support function
* We skip the first two frame numbers (0 and 1) at the beginning of each minute,
* except for minutes 0, 10, 20, 30, 40, and 50
* (i.e. we skip frame numbers at the beginning of minutes for which mins_units is not 0).
*/
static void skip_drop_frames(LTCFrame* frame) {
if ((frame->mins_units != 0)
&& (frame->secs_units == 0)
&& (frame->secs_tens == 0)
&& (frame->frame_units == 0)
&& (frame->frame_tens == 0)
) {
frame->frame_units += 2;
}
}
void ltc_frame_to_time(SMPTETimecode *stime, LTCFrame *frame, int flags) {
if (!stime) return;
if (flags & LTC_USE_DATE) {
smpte_set_timezone_string(frame, stime);
stime->years = frame->user5 + frame->user6*10;
stime->months = frame->user3 + frame->user4*10;
stime->days = frame->user1 + frame->user2*10;
} else {
stime->years = 0;
stime->months = 0;
stime->days = 0;
sprintf(stime->timezone,"+0000");
}
stime->hours = frame->hours_units + frame->hours_tens*10;
stime->mins = frame->mins_units + frame->mins_tens*10;
stime->secs = frame->secs_units + frame->secs_tens*10;
stime->frame = frame->frame_units + frame->frame_tens*10;
}
void ltc_time_to_frame(LTCFrame* frame, SMPTETimecode* stime, enum LTC_TV_STANDARD standard, int flags) {
if (flags & LTC_USE_DATE) {
smpte_set_timezone_code(stime, frame);
frame->user6 = stime->years/10;
frame->user5 = stime->years - frame->user6*10;
frame->user4 = stime->months/10;
frame->user3 = stime->months - frame->user4*10;
frame->user2 = stime->days/10;
frame->user1 = stime->days - frame->user2*10;
}
frame->hours_tens = stime->hours/10;
frame->hours_units = stime->hours - frame->hours_tens*10;
frame->mins_tens = stime->mins/10;
frame->mins_units = stime->mins - frame->mins_tens*10;
frame->secs_tens = stime->secs/10;
frame->secs_units = stime->secs - frame->secs_tens*10;
frame->frame_tens = stime->frame/10;
frame->frame_units = stime->frame - frame->frame_tens*10;
// Prevent illegal SMPTE frames
if (frame->dfbit) {
skip_drop_frames(frame);
}
if ((flags & LTC_NO_PARITY) == 0) {
ltc_frame_set_parity(frame, standard);
}
}
void ltc_frame_reset(LTCFrame* frame) {
memset(frame, 0, sizeof(LTCFrame));
// syncword = 0x3FFD
#ifdef LTC_BIG_ENDIAN
// mirrored BE bit order: FCBF
frame->sync_word = 0xFCBF;
#else
// mirrored LE bit order: BFFC
frame->sync_word = 0xBFFC;
#endif
}
int ltc_frame_increment(LTCFrame* frame, int fps, enum LTC_TV_STANDARD standard, int flags) {
int rv = 0;
frame->frame_units++;
if (frame->frame_units == 10)
{
frame->frame_units = 0;
frame->frame_tens++;
}
if (fps == frame->frame_units+frame->frame_tens*10)
{
frame->frame_units = 0;
frame->frame_tens = 0;
frame->secs_units++;
if (frame->secs_units == 10)
{
frame->secs_units = 0;
frame->secs_tens++;
if (frame->secs_tens == 6)
{
frame->secs_tens = 0;
frame->mins_units++;
if (frame->mins_units == 10)
{
frame->mins_units = 0;
frame->mins_tens++;
if (frame->mins_tens == 6)
{
frame->mins_tens = 0;
frame->hours_units++;
if (frame->hours_units == 10)
{
frame->hours_units = 0;
frame->hours_tens++;
}
if (frame->hours_units == 4 && frame->hours_tens==2)
{
/* 24h wrap around */
rv=1;
frame->hours_tens=0;
frame->hours_units = 0;
if (flags&1)
{
/* wrap date */
SMPTETimecode stime;
stime.years = frame->user5 + frame->user6*10;
stime.months = frame->user3 + frame->user4*10;
stime.days = frame->user1 + frame->user2*10;
if (stime.months > 0 && stime.months < 13)
{
unsigned char dpm[12] = {31,28,31,30,31,30,31,31,30,31,30,31};
/* proper leap-year calc:
* ((stime.years%4)==0 && ( (stime.years%100) != 0 || (stime.years%400) == 0) )
* simplified since year is 0..99
*/
if ((stime.years%4)==0 /* && stime.years!=0 */ ) /* year 2000 was a leap-year */
dpm[1]=29;
stime.days++;
if (stime.days > dpm[stime.months-1])
{
stime.days=1;
stime.months++;
if (stime.months > 12) {
stime.months=1;
stime.years=(stime.years+1)%100;
}
}
frame->user6 = stime.years/10;
frame->user5 = stime.years%10;
frame->user4 = stime.months/10;
frame->user3 = stime.months%10;
frame->user2 = stime.days/10;
frame->user1 = stime.days%10;
} else {
rv=-1;
}
}
}
}
}
}
}
}
if (frame->dfbit) {
skip_drop_frames(frame);
}
if ((flags & LTC_NO_PARITY) == 0) {
ltc_frame_set_parity(frame, standard);
}
return rv;
}
int ltc_frame_decrement(LTCFrame* frame, int fps, enum LTC_TV_STANDARD standard, int flags) {
int rv = 0;
int frames = frame->frame_units + frame->frame_tens * 10;
if (frames > 0) {
frames--;
} else {
frames = fps -1;
}
frame->frame_units = frames % 10;
frame->frame_tens = frames / 10;
if (frames == fps -1) {
int secs = frame->secs_units + frame->secs_tens * 10;
if (secs > 0) {
secs--;
} else {
secs = 59;
}
frame->secs_units = secs % 10;
frame->secs_tens = secs / 10;
if (secs == 59) {
int mins = frame->mins_units + frame->mins_tens * 10;
if (mins > 0) {
mins--;
} else {
mins = 59;
}
frame->mins_units = mins % 10;
frame->mins_tens = mins / 10;
if (mins == 59) {
int hours = frame->hours_units + frame->hours_tens * 10;
if (hours > 0) {
hours--;
} else {
hours = 23;
}
frame->hours_units = hours % 10;
frame->hours_tens = hours / 10;
if (hours == 23) {
/* 24h wrap around */
rv=1;
if (flags&LTC_USE_DATE)
{
/* wrap date */
SMPTETimecode stime;
stime.years = frame->user5 + frame->user6*10;
stime.months = frame->user3 + frame->user4*10;
stime.days = frame->user1 + frame->user2*10;
if (stime.months > 0 && stime.months < 13)
{
unsigned char dpm[12] = {31,28,31,30,31,30,31,31,30,31,30,31};
/* proper leap-year calc:
* ((stime.years%4)==0 && ( (stime.years%100) != 0 || (stime.years%400) == 0) )
* simplified since year is 0..99
*/
if ((stime.years%4)==0 /* && stime.years!=0 */ ) /* year 2000 was a leap-year */
dpm[1]=29;
//
if (stime.days > 1) {
stime.days--;
} else {
stime.months = 1 + (stime.months + 10)%12;
stime.days = dpm[stime.months-1];
if (stime.months == 12) {
stime.years=(stime.years+99)%100; // XXX
}
}
frame->user6 = stime.years/10;
frame->user5 = stime.years%10;
frame->user4 = stime.months/10;
frame->user3 = stime.months%10;
frame->user2 = stime.days/10;
frame->user1 = stime.days%10;
} else {
rv=-1;
}
}
}
}
}
}
if (frame->dfbit && /* prevent endless recursion */ fps > 2) {
if ((frame->mins_units != 0)
&& (frame->secs_units == 0)
&& (frame->secs_tens == 0)
&& (frame->frame_units == 1)
&& (frame->frame_tens == 0)
) {
ltc_frame_decrement(frame, fps, standard, flags&LTC_USE_DATE);
ltc_frame_decrement(frame, fps, standard, flags&LTC_USE_DATE);
}
}
if ((flags & LTC_NO_PARITY) == 0) {
ltc_frame_set_parity(frame, standard);
}
return rv;
}
int parse_bcg_flags(LTCFrame *f, enum LTC_TV_STANDARD standard) {
switch (standard) {
case LTC_TV_625_50: /* 25 fps mode */
return (
((f->binary_group_flag_bit0)?4:0)
| ((f->binary_group_flag_bit1)?2:0)
| ((f->biphase_mark_phase_correction)?1:0)
);
break;
default: /* 24,30 fps mode */
return (
((f->binary_group_flag_bit2)?4:0)
| ((f->binary_group_flag_bit1)?2:0)
| ((f->binary_group_flag_bit0)?1:0)
);
break;
}
}
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