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  1. /*
  2.  * Copyright (c) 2006 Smartjog S.A.S, Baptiste Coudurier <baptiste.coudurier@gmail.com>
  3.  * Copyright (c) 2011-2012 Smartjog S.A.S, Clément Bœsch <clement.boesch@smartjog.com>
  4.  *
  5.  * This file is part of FFmpeg.
  6.  *
  7.  * FFmpeg is free software; you can redistribute it and/or
  8.  * modify it under the terms of the GNU Lesser General Public
  9.  * License as published by the Free Software Foundation; either
  10.  * version 2.1 of the License, or (at your option) any later version.
  11.  *
  12.  * FFmpeg is distributed in the hope that it will be useful,
  13.  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14.  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15.  * Lesser General Public License for more details.
  16.  *
  17.  * You should have received a copy of the GNU Lesser General Public
  18.  * License along with FFmpeg; if not, write to the Free Software
  19.  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  20.  */
  21.  
  22. /**
  23.  * @file
  24.  * Timecode helpers
  25.  * @see https://en.wikipedia.org/wiki/SMPTE_time_code
  26.  * @see http://www.dropframetimecode.org
  27.  */
  28.  
  29. #include <stdio.h>
  30. #include "timecode.h"
  31. #include "log.h"
  32. #include "error.h"
  33.  
  34. int av_timecode_adjust_ntsc_framenum2(int framenum, int fps)
  35. {
  36.     /* only works for NTSC 29.97 and 59.94 */
  37.     int drop_frames = 0;
  38.     int d, m, frames_per_10mins;
  39.  
  40.     if (fps == 30) {
  41.         drop_frames = 2;
  42.         frames_per_10mins = 17982;
  43.     } else if (fps == 60) {
  44.         drop_frames = 4;
  45.         frames_per_10mins = 35964;
  46.     } else
  47.         return framenum;
  48.  
  49.     d = framenum / frames_per_10mins;
  50.     m = framenum % frames_per_10mins;
  51.  
  52.     return framenum + 9 * drop_frames * d + drop_frames * ((m - drop_frames) / (frames_per_10mins / 10));
  53. }
  54.  
  55. uint32_t av_timecode_get_smpte_from_framenum(const AVTimecode *tc, int framenum)
  56. {
  57.     unsigned fps = tc->fps;
  58.     int drop = !!(tc->flags & AV_TIMECODE_FLAG_DROPFRAME);
  59.     int hh, mm, ss, ff;
  60.  
  61.     framenum += tc->start;
  62.     if (drop)
  63.         framenum = av_timecode_adjust_ntsc_framenum2(framenum, tc->fps);
  64.     ff = framenum % fps;
  65.     ss = framenum / fps      % 60;
  66.     mm = framenum / (fps*60) % 60;
  67.     hh = framenum / (fps*3600) % 24;
  68.     return 0         << 31 | // color frame flag (0: unsync mode, 1: sync mode)
  69.            drop      << 30 | // drop  frame flag (0: non drop,    1: drop)
  70.            (ff / 10) << 28 | // tens  of frames
  71.            (ff % 10) << 24 | // units of frames
  72.            0         << 23 | // PC (NTSC) or BGF0 (PAL)
  73.            (ss / 10) << 20 | // tens  of seconds
  74.            (ss % 10) << 16 | // units of seconds
  75.            0         << 15 | // BGF0 (NTSC) or BGF2 (PAL)
  76.            (mm / 10) << 12 | // tens  of minutes
  77.            (mm % 10) <<  8 | // units of minutes
  78.            0         <<  7 | // BGF2 (NTSC) or PC (PAL)
  79.            0         <<  6 | // BGF1
  80.            (hh / 10) <<  4 | // tens  of hours
  81.            (hh % 10);        // units of hours
  82. }
  83.  
  84. char *av_timecode_make_string(const AVTimecode *tc, char *buf, int framenum)
  85. {
  86.     int fps = tc->fps;
  87.     int drop = tc->flags & AV_TIMECODE_FLAG_DROPFRAME;
  88.     int hh, mm, ss, ff, neg = 0;
  89.  
  90.     framenum += tc->start;
  91.     if (drop)
  92.         framenum = av_timecode_adjust_ntsc_framenum2(framenum, fps);
  93.     if (framenum < 0) {
  94.         framenum = -framenum;
  95.         neg = tc->flags & AV_TIMECODE_FLAG_ALLOWNEGATIVE;
  96.     }
  97.     ff = framenum % fps;
  98.     ss = framenum / fps        % 60;
  99.     mm = framenum / (fps*60)   % 60;
  100.     hh = framenum / (fps*3600);
  101.     if (tc->flags & AV_TIMECODE_FLAG_24HOURSMAX)
  102.         hh = hh % 24;
  103.     snprintf(buf, AV_TIMECODE_STR_SIZE, "%s%02d:%02d:%02d%c%02d",
  104.              neg ? "-" : "",
  105.              hh, mm, ss, drop ? ';' : ':', ff);
  106.     return buf;
  107. }
  108.  
  109. static unsigned bcd2uint(uint8_t bcd)
  110. {
  111.    unsigned low  = bcd & 0xf;
  112.    unsigned high = bcd >> 4;
  113.    if (low > 9 || high > 9)
  114.        return 0;
  115.    return low + 10*high;
  116. }
  117.  
  118. char *av_timecode_make_smpte_tc_string(char *buf, uint32_t tcsmpte, int prevent_df)
  119. {
  120.     unsigned hh   = bcd2uint(tcsmpte     & 0x3f);    // 6-bit hours
  121.     unsigned mm   = bcd2uint(tcsmpte>>8  & 0x7f);    // 7-bit minutes
  122.     unsigned ss   = bcd2uint(tcsmpte>>16 & 0x7f);    // 7-bit seconds
  123.     unsigned ff   = bcd2uint(tcsmpte>>24 & 0x3f);    // 6-bit frames
  124.     unsigned drop = tcsmpte & 1<<30 && !prevent_df;  // 1-bit drop if not arbitrary bit
  125.     snprintf(buf, AV_TIMECODE_STR_SIZE, "%02u:%02u:%02u%c%02u",
  126.              hh, mm, ss, drop ? ';' : ':', ff);
  127.     return buf;
  128. }
  129.  
  130. char *av_timecode_make_mpeg_tc_string(char *buf, uint32_t tc25bit)
  131. {
  132.     snprintf(buf, AV_TIMECODE_STR_SIZE, "%02u:%02u:%02u%c%02u",
  133.              tc25bit>>19 & 0x1f,              // 5-bit hours
  134.              tc25bit>>13 & 0x3f,              // 6-bit minutes
  135.              tc25bit>>6  & 0x3f,              // 6-bit seconds
  136.              tc25bit     & 1<<24 ? ';' : ':', // 1-bit drop flag
  137.              tc25bit     & 0x3f);             // 6-bit frames
  138.     return buf;
  139. }
  140.  
  141. static int check_fps(int fps)
  142. {
  143.     int i;
  144.     static const int supported_fps[] = {24, 25, 30, 50, 60};
  145.  
  146.     for (i = 0; i < FF_ARRAY_ELEMS(supported_fps); i++)
  147.         if (fps == supported_fps[i])
  148.             return 0;
  149.     return -1;
  150. }
  151.  
  152. static int check_timecode(void *log_ctx, AVTimecode *tc)
  153. {
  154.     if (tc->fps <= 0) {
  155.         av_log(log_ctx, AV_LOG_ERROR, "Timecode frame rate must be specified\n");
  156.         return AVERROR(EINVAL);
  157.     }
  158.     if ((tc->flags & AV_TIMECODE_FLAG_DROPFRAME) && tc->fps != 30 && tc->fps != 60) {
  159.         av_log(log_ctx, AV_LOG_ERROR, "Drop frame is only allowed with 30000/1001 or 60000/1001 FPS\n");
  160.         return AVERROR(EINVAL);
  161.     }
  162.     if (check_fps(tc->fps) < 0) {
  163.         av_log(log_ctx, AV_LOG_ERROR, "Timecode frame rate %d/%d not supported\n",
  164.                tc->rate.num, tc->rate.den);
  165.         return AVERROR_PATCHWELCOME;
  166.     }
  167.     return 0;
  168. }
  169.  
  170. static int fps_from_frame_rate(AVRational rate)
  171. {
  172.     if (!rate.den || !rate.num)
  173.         return -1;
  174.     return (rate.num + rate.den/2) / rate.den;
  175. }
  176.  
  177. int av_timecode_check_frame_rate(AVRational rate)
  178. {
  179.     return check_fps(fps_from_frame_rate(rate));
  180. }
  181.  
  182. int av_timecode_init(AVTimecode *tc, AVRational rate, int flags, int frame_start, void *log_ctx)
  183. {
  184.     memset(tc, 0, sizeof(*tc));
  185.     tc->start = frame_start;
  186.     tc->flags = flags;
  187.     tc->rate  = rate;
  188.     tc->fps   = fps_from_frame_rate(rate);
  189.     return check_timecode(log_ctx, tc);
  190. }
  191.  
  192. int av_timecode_init_from_string(AVTimecode *tc, AVRational rate, const char *str, void *log_ctx)
  193. {
  194.     char c;
  195.     int hh, mm, ss, ff, ret;
  196.  
  197.     if (sscanf(str, "%d:%d:%d%c%d", &hh, &mm, &ss, &c, &ff) != 5) {
  198.         av_log(log_ctx, AV_LOG_ERROR, "Unable to parse timecode, "
  199.                                       "syntax: hh:mm:ss[:;.]ff\n");
  200.         return AVERROR_INVALIDDATA;
  201.     }
  202.  
  203.     memset(tc, 0, sizeof(*tc));
  204.     tc->flags = c != ':' ? AV_TIMECODE_FLAG_DROPFRAME : 0; // drop if ';', '.', ...
  205.     tc->rate  = rate;
  206.     tc->fps   = fps_from_frame_rate(rate);
  207.  
  208.     ret = check_timecode(log_ctx, tc);
  209.     if (ret < 0)
  210.         return ret;
  211.  
  212.     tc->start = (hh*3600 + mm*60 + ss) * tc->fps + ff;
  213.     if (tc->flags & AV_TIMECODE_FLAG_DROPFRAME) { /* adjust frame number */
  214.         int tmins = 60*hh + mm;
  215.         tc->start -= 2 * (tmins - tmins/10);
  216.     }
  217.     return 0;
  218. }
  219.