libs/libltc/timecode.c

   1 /*
   2    libltc - en+decode linear timecode
   3
   4    Copyright (C) 2006-2012 Robin Gareus <robin@gareus.org>
   5
   6    This program is free software; you can redistribute it and/or modify
   7    it under the terms of the GNU Lesser General Public License as
   8    published by the Free Software Foundation, either version 3 of the
   9    License, or (at your option) any later version.
  10
  11    This program is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14    GNU Lesser General Public License for more details.
  15
  16    You should have received a copy of the GNU Lesser General Public
  17    License along with this library.
  18    If not, see <http://www.gnu.org/licenses/>.
  19 */
  20
  21 #include <stdio.h>
  22 #include <stdlib.h>
  23 #include <string.h>
  24
  25 #include "ltc/ltc.h"
  26
  27 #ifdef HAVE_CONFIG_H
  28 # include <config.h>
  29 #endif
  30
  31 /**
  32  * SMPTE Timezones
  33  */
  34 struct SMPTETimeZonesStruct {
  35         unsigned char code; //actually 6 bit!
  36         char timezone[6];
  37 };
  38
  39 /**
  40  * SMPTE Timezone codes as per http://www.barney-wol.net/time/timecode.html
  41  */
  42 static const struct SMPTETimeZonesStruct smpte_time_zones[] =
  43 {
  44     /*  code,   timezone (UTC+)     //Standard time                 //Daylight saving   */
  45     {   0x00,   "+0000"             /* Greenwich */                 /* - */             },
  46     {   0x00,   "-0000"             /* Greenwich */                 /* - */             },
  47     {   0x01,   "-0100"             /* Azores */                    /* - */             },
  48     {   0x02,   "-0200"             /* Mid-Atlantic */              /* - */             },
  49     {   0x03,   "-0300"             /* Buenos Aires */              /* Halifax */       },
  50     {   0x04,   "-0400"             /* Halifax */                   /* New York */      },
  51     {   0x05,   "-0500"             /* New York */                  /* Chicago */       },
  52     {   0x06,   "-0600"             /* Chicago Denver */            /* - */             },
  53     {   0x07,   "-0700"             /* Denver */                    /* Los Angeles */   },
  54     {   0x08,   "-0800"             /* Los Angeles */               /* - */             },
  55     {   0x09,   "-0900"             /* Alaska */                    /* - */             },
  56     {   0x10,   "-1000"             /* Hawaii */                    /* - */             },
  57     {   0x11,   "-1100"             /* Midway Island */             /* - */             },
  58     {   0x12,   "-1200"             /* Kwaialein */                 /* - */             },
  59     {   0x13,   "+1300"             /* - */                         /* New Zealand */   },
  60     {   0x14,   "+1200"             /* New Zealand */               /* - */             },
  61     {   0x15,   "+1100"             /* Solomon Islands */           /* - */             },
  62     {   0x16,   "+1000"             /* Guam */                      /* - */             },
  63     {   0x17,   "+0900"             /* Tokyo */                     /* - */             },
  64     {   0x18,   "+0800"             /* Beijing */                   /* - */             },
  65     {   0x19,   "+0700"             /* Bangkok */                   /* - */             },
  66     {   0x20,   "+0600"             /* Dhaka */                     /* - */             },
  67     {   0x21,   "+0500"             /* Islamabad */                 /* - */             },
  68     {   0x22,   "+0400"             /* Abu Dhabi */                 /* - */             },
  69     {   0x23,   "+0300"             /* Moscow */                    /* - */             },
  70     {   0x24,   "+0200"             /* Eastern Europe */            /* - */             },
  71     {   0x25,   "+0100"             /* Central Europe */            /* - */             },
  72 /*  {   0x26,   "Undefined"         Reserved; do not use                                },*/
  73 /*  {   0x27,   "Undefined"         Reserved; do not use                                },*/
  74     {   0x28,   "TP-03"             /* Time precision class 3 */    /* - */             },
  75     {   0x29,   "TP-02"             /* Time precision class 2 */    /* - */             },
  76     {   0x30,   "TP-01"             /* Time precision class 1 */    /* - */             },
  77     {   0x31,   "TP-00"             /* Time precision class 0 */    /* - */             },
  78     {   0x0A,   "-0030"             /* - */                         /* - */             },
  79     {   0x0B,   "-0130"             /* - */                         /* - */             },
  80     {   0x0C,   "-0230"             /* - */                         /* Newfoundland */  },
  81     {   0x0D,   "-0330"             /* Newfoundland */              /* - */             },
  82     {   0x0E,   "-0430"             /* - */                         /* - */             },
  83     {   0x0F,   "-0530"             /* - */                         /* - */             },
  84     {   0x1A,   "-0630"             /* - */                         /* - */             },
  85     {   0x1B,   "-0730"             /* - */                         /* - */             },
  86     {   0x1C,   "-0830"             /* - */                         /* - */             },
  87     {   0x1D,   "-0930"             /* Marquesa Islands */          /* - */             },
  88     {   0x1E,   "-1030"             /* - */                         /* - */             },
  89     {   0x1F,   "-1130"             /* - */                         /* - */             },
  90     {   0x2A,   "+1130"             /* Norfolk Island */            /* - */             },
  91     {   0x2B,   "+1030"             /* Lord Howe Is. */             /* - */             },
  92     {   0x2C,   "+0930"             /* Darwin */                    /* - */             },
  93     {   0x2D,   "+0830"             /* - */                         /* - */             },
  94     {   0x2E,   "+0730"             /* - */                         /* - */             },
  95     {   0x2F,   "+0630"             /* Rangoon */                   /* - */             },
  96     {   0x3A,   "+0530"             /* Bombay */                    /* - */             },
  97     {   0x3B,   "+0430"             /* Kabul */                     /* - */             },
  98     {   0x3C,   "+0330"             /* Tehran */                    /* - */             },
  99     {   0x3D,   "+0230"             /* - */                         /* - */             },
 100     {   0x3E,   "+0130"             /* - */                         /* - */             },
 101     {   0x3F,   "+0030"             /* - */                         /* - */             },
 102     {   0x32,   "+1245"             /* Chatham Island */            /* - */             },
 103 /*  {   0x33,   "Undefined"         Reserved; do not use                                },*/
 104 /*  {   0x34,   "Undefined"         Reserved; do not use                                },*/
 105 /*  {   0x35,   "Undefined"         Reserved; do not use                                },*/
 106 /*  {   0x36,   "Undefined"         Reserved; do not use                                },*/
 107 /*  {   0x37,   "Undefined"         Reserved; do not use                                },*/
 108     {   0x38,   "+XXXX"             /* User defined time offset */  /* - */             },
 109 /*  {   0x39,   "Undefined"         Unknown                         Unknown             },*/
 110 /*  {   0x39,   "Undefined"         Unknown                         Unknown             },*/
 111
 112     {   0xFF,   ""                  /* The End */                                       }
 113 };
 114
 115 static void smpte_set_timezone_string(LTCFrame *frame, SMPTETimecode *stime) {
 116         int i = 0;
 117
 118         const unsigned char code = frame->user7 + (frame->user8 << 4);
 119
 120         char timezone[6] = "+0000";
 121
 122         for (i = 0 ; smpte_time_zones[i].code != 0xFF ; i++) {
 123                 if ( smpte_time_zones[i].code == code ) {
 124                         strcpy(timezone, smpte_time_zones[i].timezone);
 125                         break;
 126                 }
 127         }
 128         strcpy(stime->timezone, timezone);
 129 }
 130
 131 static void smpte_set_timezone_code(SMPTETimecode *stime, LTCFrame *frame) {
 132         int i = 0;
 133         unsigned char code = 0x00;
 134
 135         // Find code for timezone string
 136         // Primitive search
 137         for (i=0; smpte_time_zones[i].code != 0xFF; i++) {
 138                 if ( (strcmp(smpte_time_zones[i].timezone, stime->timezone)) == 0 ) {
 139                         code = smpte_time_zones[i].code;
 140                         break;
 141                 }
 142         }
 143
 144         frame->user7 = code & 0x0F;
 145         frame->user8 = (code & 0xF0) >> 4;
 146 }
 147
 148 /** Drop-frame support function
 149  * We skip the first two frame numbers (0 and 1) at the beginning of each minute,
 150  * except for minutes 0, 10, 20, 30, 40, and 50
 151  * (i.e. we skip frame numbers at the beginning of minutes for which mins_units is not 0).
 152  */
 153 static void skip_drop_frames(LTCFrame* frame) {
 154         if ((frame->mins_units != 0)
 155                 && (frame->secs_units == 0)
 156                 && (frame->secs_tens == 0)
 157                 && (frame->frame_units == 0)
 158                 && (frame->frame_tens == 0)
 159                 ) {
 160                 frame->frame_units += 2;
 161         }
 162 }
 163
 164 void ltc_frame_to_time(SMPTETimecode *stime, LTCFrame *frame, int flags) {
 165         if (!stime) return;
 166
 167         if (flags & LTC_USE_DATE) {
 168                 smpte_set_timezone_string(frame, stime);
 169
 170                 stime->years  = frame->user5 + frame->user6*10;
 171                 stime->months = frame->user3 + frame->user4*10;
 172                 stime->days   = frame->user1 + frame->user2*10;
 173         } else {
 174                 stime->years  = 0;
 175                 stime->months = 0;
 176                 stime->days   = 0;
 177                 sprintf(stime->timezone,"+0000");
 178         }
 179
 180         stime->hours = frame->hours_units + frame->hours_tens*10;
 181         stime->mins  = frame->mins_units  + frame->mins_tens*10;
 182         stime->secs  = frame->secs_units  + frame->secs_tens*10;
 183         stime->frame = frame->frame_units + frame->frame_tens*10;
 184 }
 185
 186 void ltc_time_to_frame(LTCFrame* frame, SMPTETimecode* stime, enum LTC_TV_STANDARD standard, int flags) {
 187         if (flags & LTC_USE_DATE) {
 188                 smpte_set_timezone_code(stime, frame);
 189                 frame->user6 = stime->years/10;
 190                 frame->user5 = stime->years - frame->user6*10;
 191                 frame->user4 = stime->months/10;
 192                 frame->user3 = stime->months - frame->user4*10;
 193                 frame->user2 = stime->days/10;
 194                 frame->user1 = stime->days - frame->user2*10;
 195         }
 196
 197         frame->hours_tens  = stime->hours/10;
 198         frame->hours_units = stime->hours - frame->hours_tens*10;
 199         frame->mins_tens   = stime->mins/10;
 200         frame->mins_units  = stime->mins - frame->mins_tens*10;
 201         frame->secs_tens   = stime->secs/10;
 202         frame->secs_units  = stime->secs - frame->secs_tens*10;
 203         frame->frame_tens  = stime->frame/10;
 204         frame->frame_units = stime->frame - frame->frame_tens*10;
 205
 206         // Prevent illegal SMPTE frames
 207         if (frame->dfbit) {
 208                 skip_drop_frames(frame);
 209         }
 210
 211         if ((flags & LTC_NO_PARITY) == 0) {
 212                 ltc_frame_set_parity(frame, standard);
 213         }
 214 }
 215
 216 void ltc_frame_reset(LTCFrame* frame) {
 217         memset(frame, 0, sizeof(LTCFrame));
 218         // syncword = 0x3FFD
 219 #ifdef __BIG_ENDIAN__
 220         // mirrored BE bit order: FCBF
 221         frame->sync_word = 0xFCBF;
 222 #else
 223         // mirrored LE bit order: BFFC
 224         frame->sync_word = 0xBFFC;
 225 #endif
 226 }
 227
 228 int ltc_frame_increment(LTCFrame* frame, int fps, enum LTC_TV_STANDARD standard, int flags) {
 229         int rv = 0;
 230
 231         frame->frame_units++;
 232
 233         if (frame->frame_units == 10)
 234         {
 235                 frame->frame_units = 0;
 236                 frame->frame_tens++;
 237         }
 238         if (fps == frame->frame_units+frame->frame_tens*10)
 239         {
 240                 frame->frame_units = 0;
 241                 frame->frame_tens = 0;
 242                 frame->secs_units++;
 243                 if (frame->secs_units == 10)
 244                 {
 245                         frame->secs_units = 0;
 246                         frame->secs_tens++;
 247                         if (frame->secs_tens == 6)
 248                         {
 249                                 frame->secs_tens = 0;
 250                                 frame->mins_units++;
 251                                 if (frame->mins_units == 10)
 252                                 {
 253                                         frame->mins_units = 0;
 254                                         frame->mins_tens++;
 255                                         if (frame->mins_tens == 6)
 256                                         {
 257                                                 frame->mins_tens = 0;
 258                                                 frame->hours_units++;
 259                                                 if (frame->hours_units == 10)
 260                                                 {
 261                                                         frame->hours_units = 0;
 262                                                         frame->hours_tens++;
 263                                                 }
 264                                                 if (frame->hours_units == 4 && frame->hours_tens==2)
 265                                                 {
 266                                                         /* 24h wrap around */
 267                                                         rv=1;
 268                                                         frame->hours_tens=0;
 269                                                         frame->hours_units = 0;
 270
 271                                                         if (flags&1)
 272                                                         {
 273                                                                 /* wrap date */
 274                                                                 SMPTETimecode stime;
 275                                                                 stime.years  = frame->user5 + frame->user6*10;
 276                                                                 stime.months = frame->user3 + frame->user4*10;
 277                                                                 stime.days   = frame->user1 + frame->user2*10;
 278
 279                                                                 if (stime.months > 0 && stime.months < 13)
 280                                                                 {
 281                                                                         unsigned char dpm[12] = {31,28,31,30,31,30,31,31,30,31,30,31};
 282                                                                         /* proper leap-year calc:
 283                                                                          * ((stime.years%4)==0 && ( (stime.years%100) != 0 || (stime.years%400) == 0) )
 284                                                                          * simplified since year is 0..99
 285                                                                          */
 286                                                                         if ((stime.years%4)==0 /* && stime.years!=0 */ ) /* year 2000 was a leap-year */
 287                                                                                 dpm[1]=29;
 288                                                                         stime.days++;
 289                                                                         if (stime.days > dpm[stime.months-1])
 290                                                                         {
 291                                                                                 stime.days=1;
 292                                                                                 stime.months++;
 293                                                                                 if (stime.months > 12) {
 294                                                                                         stime.months=1;
 295                                                                                         stime.years=(stime.years+1)%100;
 296                                                                                 }
 297                                                                         }
 298                                                                         frame->user6 = stime.years/10;
 299                                                                         frame->user5 = stime.years%10;
 300                                                                         frame->user4 = stime.months/10;
 301                                                                         frame->user3 = stime.months%10;
 302                                                                         frame->user2 = stime.days/10;
 303                                                                         frame->user1 = stime.days%10;
 304                                                                 } else {
 305                                                                         rv=-1;
 306                                                                 }
 307                                                         }
 308                                                 }
 309                                         }
 310                                 }
 311                         }
 312                 }
 313         }
 314
 315         if (frame->dfbit) {
 316                 skip_drop_frames(frame);
 317         }
 318
 319         if ((flags & LTC_NO_PARITY) == 0) {
 320                 ltc_frame_set_parity(frame, standard);
 321         }
 322
 323         return rv;
 324 }
 325
 326 int ltc_frame_decrement(LTCFrame* frame, int fps, enum LTC_TV_STANDARD standard, int flags) {
 327         int rv = 0;
 328
 329         int frames = frame->frame_units + frame->frame_tens * 10;
 330         if (frames > 0) {
 331                 frames--;
 332         } else {
 333                 frames = fps -1;
 334         }
 335
 336         frame->frame_units = frames % 10;
 337         frame->frame_tens  = frames / 10;
 338
 339         if (frames == fps -1) {
 340                 int secs = frame->secs_units + frame->secs_tens * 10;
 341                 if (secs > 0) {
 342                         secs--;
 343                 } else {
 344                         secs = 59;
 345                 }
 346                 frame->secs_units = secs % 10;
 347                 frame->secs_tens  = secs / 10;
 348
 349                 if (secs == 59) {
 350                         int mins = frame->mins_units + frame->mins_tens * 10;
 351                         if (mins > 0) {
 352                                 mins--;
 353                         } else {
 354                                 mins = 59;
 355                         }
 356                         frame->mins_units = mins % 10;
 357                         frame->mins_tens  = mins / 10;
 358
 359                         if (mins == 59) {
 360                                 int hours = frame->hours_units + frame->hours_tens * 10;
 361                                 if (hours > 0) {
 362                                         hours--;
 363                                 } else {
 364                                         hours = 23;
 365                                 }
 366                                 frame->hours_units = hours % 10;
 367                                 frame->hours_tens  = hours / 10;
 368
 369                                 if (hours == 23) {
 370                                         /* 24h wrap around */
 371                                         rv=1;
 372                                         if (flags&LTC_USE_DATE)
 373                                         {
 374                                                 /* wrap date */
 375                                                 SMPTETimecode stime;
 376                                                 stime.years  = frame->user5 + frame->user6*10;
 377                                                 stime.months = frame->user3 + frame->user4*10;
 378                                                 stime.days   = frame->user1 + frame->user2*10;
 379
 380                                                 if (stime.months > 0 && stime.months < 13)
 381                                                 {
 382                                                         unsigned char dpm[12] = {31,28,31,30,31,30,31,31,30,31,30,31};
 383                                                         /* proper leap-year calc:
 384                                                          * ((stime.years%4)==0 && ( (stime.years%100) != 0 || (stime.years%400) == 0) )
 385                                                          * simplified since year is 0..99
 386                                                          */
 387                                                         if ((stime.years%4)==0 /* && stime.years!=0 */ ) /* year 2000 was a leap-year */
 388                                                                 dpm[1]=29;
 389                                                         //
 390                                                         if (stime.days > 1) {
 391                                                                 stime.days--;
 392                                                         } else {
 393                                                                 stime.months = 1 + (stime.months + 10)%12;
 394                                                                 stime.days = dpm[stime.months-1];
 395                                                                 if (stime.months == 12)  {
 396                                                                         stime.years=(stime.years+99)%100; // XXX
 397                                                                 }
 398                                                         }
 399
 400                                                         frame->user6 = stime.years/10;
 401                                                         frame->user5 = stime.years%10;
 402                                                         frame->user4 = stime.months/10;
 403                                                         frame->user3 = stime.months%10;
 404                                                         frame->user2 = stime.days/10;
 405                                                         frame->user1 = stime.days%10;
 406                                                 } else {
 407                                                         rv=-1;
 408                                                 }
 409                                         }
 410                                 }
 411                         }
 412                 }
 413         }
 414
 415         if (frame->dfbit && /* prevent endless recursion */ fps > 2) {
 416                 if ((frame->mins_units != 0)
 417                         && (frame->secs_units == 0)
 418                         && (frame->secs_tens == 0)
 419                         && (frame->frame_units == 1)
 420                         && (frame->frame_tens == 0)
 421                         ) {
 422                         ltc_frame_decrement(frame, fps, standard, flags&LTC_USE_DATE);
 423                         ltc_frame_decrement(frame, fps, standard, flags&LTC_USE_DATE);
 424                 }
 425         }
 426
 427         if ((flags & LTC_NO_PARITY) == 0) {
 428                 ltc_frame_set_parity(frame, standard);
 429         }
 430
 431         return rv;
 432 }
 433
 434 int parse_bcg_flags(LTCFrame *f, enum LTC_TV_STANDARD standard) {
 435         switch (standard) {
 436                 case LTC_TV_625_50: /* 25 fps mode */
 437                         return (
 438                                           ((f->binary_group_flag_bit0)?4:0)
 439                                         | ((f->binary_group_flag_bit1)?2:0)
 440                                         | ((f->biphase_mark_phase_correction)?1:0)
 441                                         );
 442                         break;
 443                 default: /* 24,30 fps mode */
 444                         return (
 445                                           ((f->binary_group_flag_bit2)?4:0)
 446                                         | ((f->binary_group_flag_bit1)?2:0)
 447                                         | ((f->binary_group_flag_bit0)?1:0)
 448                                         );
 449                         break;
 450         }
 451 }