timecode.c 7.1 KB

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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. * @file
  23. * Timecode helpers
  24. * @see https://en.wikipedia.org/wiki/SMPTE_time_code
  25. * @see http://www.dropframetimecode.org
  26. */
  27. #include <stdio.h>
  28. #include "timecode.h"
  29. #include "log.h"
  30. #include "error.h"
  31. int av_timecode_adjust_ntsc_framenum2(int framenum, int fps)
  32. {
  33. /* only works for NTSC 29.97 and 59.94 */
  34. int drop_frames = 0;
  35. int d, m, frames_per_10mins;
  36. if (fps == 30) {
  37. drop_frames = 2;
  38. frames_per_10mins = 17982;
  39. } else if (fps == 60) {
  40. drop_frames = 4;
  41. frames_per_10mins = 35964;
  42. } else
  43. return framenum;
  44. d = framenum / frames_per_10mins;
  45. m = framenum % frames_per_10mins;
  46. return framenum + 9 * drop_frames * d + drop_frames * ((m - drop_frames) / (frames_per_10mins / 10));
  47. }
  48. uint32_t av_timecode_get_smpte_from_framenum(const AVTimecode *tc, int framenum)
  49. {
  50. unsigned fps = tc->fps;
  51. int drop = !!(tc->flags & AV_TIMECODE_FLAG_DROPFRAME);
  52. int hh, mm, ss, ff;
  53. framenum += tc->start;
  54. if (drop)
  55. framenum = av_timecode_adjust_ntsc_framenum2(framenum, tc->fps);
  56. ff = framenum % fps;
  57. ss = framenum / fps % 60;
  58. mm = framenum / (fps*60) % 60;
  59. hh = framenum / (fps*3600) % 24;
  60. return 0 << 31 | // color frame flag (0: unsync mode, 1: sync mode)
  61. drop << 30 | // drop frame flag (0: non drop, 1: drop)
  62. (ff / 10) << 28 | // tens of frames
  63. (ff % 10) << 24 | // units of frames
  64. 0 << 23 | // PC (NTSC) or BGF0 (PAL)
  65. (ss / 10) << 20 | // tens of seconds
  66. (ss % 10) << 16 | // units of seconds
  67. 0 << 15 | // BGF0 (NTSC) or BGF2 (PAL)
  68. (mm / 10) << 12 | // tens of minutes
  69. (mm % 10) << 8 | // units of minutes
  70. 0 << 7 | // BGF2 (NTSC) or PC (PAL)
  71. 0 << 6 | // BGF1
  72. (hh / 10) << 4 | // tens of hours
  73. (hh % 10); // units of hours
  74. }
  75. char *av_timecode_make_string(const AVTimecode *tc, char *buf, int framenum)
  76. {
  77. int fps = tc->fps;
  78. int drop = tc->flags & AV_TIMECODE_FLAG_DROPFRAME;
  79. int hh, mm, ss, ff, neg = 0;
  80. framenum += tc->start;
  81. if (drop)
  82. framenum = av_timecode_adjust_ntsc_framenum2(framenum, fps);
  83. if (framenum < 0) {
  84. framenum = -framenum;
  85. neg = tc->flags & AV_TIMECODE_FLAG_ALLOWNEGATIVE;
  86. }
  87. ff = framenum % fps;
  88. ss = framenum / fps % 60;
  89. mm = framenum / (fps*60) % 60;
  90. hh = framenum / (fps*3600);
  91. if (tc->flags & AV_TIMECODE_FLAG_24HOURSMAX)
  92. hh = hh % 24;
  93. snprintf(buf, AV_TIMECODE_STR_SIZE, "%s%02d:%02d:%02d%c%02d",
  94. neg ? "-" : "",
  95. hh, mm, ss, drop ? ';' : ':', ff);
  96. return buf;
  97. }
  98. static unsigned bcd2uint(uint8_t bcd)
  99. {
  100. unsigned low = bcd & 0xf;
  101. unsigned high = bcd >> 4;
  102. if (low > 9 || high > 9)
  103. return 0;
  104. return low + 10*high;
  105. }
  106. char *av_timecode_make_smpte_tc_string(char *buf, uint32_t tcsmpte, int prevent_df)
  107. {
  108. unsigned hh = bcd2uint(tcsmpte & 0x3f); // 6-bit hours
  109. unsigned mm = bcd2uint(tcsmpte>>8 & 0x7f); // 7-bit minutes
  110. unsigned ss = bcd2uint(tcsmpte>>16 & 0x7f); // 7-bit seconds
  111. unsigned ff = bcd2uint(tcsmpte>>24 & 0x3f); // 6-bit frames
  112. unsigned drop = tcsmpte & 1<<30 && !prevent_df; // 1-bit drop if not arbitrary bit
  113. snprintf(buf, AV_TIMECODE_STR_SIZE, "%02u:%02u:%02u%c%02u",
  114. hh, mm, ss, drop ? ';' : ':', ff);
  115. return buf;
  116. }
  117. char *av_timecode_make_mpeg_tc_string(char *buf, uint32_t tc25bit)
  118. {
  119. snprintf(buf, AV_TIMECODE_STR_SIZE, "%02u:%02u:%02u%c%02u",
  120. tc25bit>>19 & 0x1f, // 5-bit hours
  121. tc25bit>>13 & 0x3f, // 6-bit minutes
  122. tc25bit>>6 & 0x3f, // 6-bit seconds
  123. tc25bit & 1<<24 ? ';' : ':', // 1-bit drop flag
  124. tc25bit & 0x3f); // 6-bit frames
  125. return buf;
  126. }
  127. static int check_fps(int fps)
  128. {
  129. int i;
  130. static const int supported_fps[] = {24, 25, 30, 50, 60};
  131. for (i = 0; i < FF_ARRAY_ELEMS(supported_fps); i++)
  132. if (fps == supported_fps[i])
  133. return 0;
  134. return -1;
  135. }
  136. static int check_timecode(void *log_ctx, AVTimecode *tc)
  137. {
  138. if (tc->fps <= 0) {
  139. av_log(log_ctx, AV_LOG_ERROR, "Timecode frame rate must be specified\n");
  140. return AVERROR(EINVAL);
  141. }
  142. if ((tc->flags & AV_TIMECODE_FLAG_DROPFRAME) && tc->fps != 30 && tc->fps != 60) {
  143. av_log(log_ctx, AV_LOG_ERROR, "Drop frame is only allowed with 30000/1001 or 60000/1001 FPS\n");
  144. return AVERROR(EINVAL);
  145. }
  146. if (check_fps(tc->fps) < 0) {
  147. av_log(log_ctx, AV_LOG_ERROR, "Timecode frame rate %d/%d not supported\n",
  148. tc->rate.num, tc->rate.den);
  149. return AVERROR_PATCHWELCOME;
  150. }
  151. return 0;
  152. }
  153. static int fps_from_frame_rate(AVRational rate)
  154. {
  155. if (!rate.den || !rate.num)
  156. return -1;
  157. return (rate.num + rate.den/2) / rate.den;
  158. }
  159. int av_timecode_check_frame_rate(AVRational rate)
  160. {
  161. return check_fps(fps_from_frame_rate(rate));
  162. }
  163. int av_timecode_init(AVTimecode *tc, AVRational rate, int flags, int frame_start, void *log_ctx)
  164. {
  165. memset(tc, 0, sizeof(*tc));
  166. tc->start = frame_start;
  167. tc->flags = flags;
  168. tc->rate = rate;
  169. tc->fps = fps_from_frame_rate(rate);
  170. return check_timecode(log_ctx, tc);
  171. }
  172. int av_timecode_init_from_string(AVTimecode *tc, AVRational rate, const char *str, void *log_ctx)
  173. {
  174. char c;
  175. int hh, mm, ss, ff, ret;
  176. if (sscanf(str, "%d:%d:%d%c%d", &hh, &mm, &ss, &c, &ff) != 5) {
  177. av_log(log_ctx, AV_LOG_ERROR, "Unable to parse timecode, "
  178. "syntax: hh:mm:ss[:;.]ff\n");
  179. return AVERROR_INVALIDDATA;
  180. }
  181. memset(tc, 0, sizeof(*tc));
  182. tc->flags = c != ':' ? AV_TIMECODE_FLAG_DROPFRAME : 0; // drop if ';', '.', ...
  183. tc->rate = rate;
  184. tc->fps = fps_from_frame_rate(rate);
  185. ret = check_timecode(log_ctx, tc);
  186. if (ret < 0)
  187. return ret;
  188. tc->start = (hh*3600 + mm*60 + ss) * tc->fps + ff;
  189. if (tc->flags & AV_TIMECODE_FLAG_DROPFRAME) { /* adjust frame number */
  190. int tmins = 60*hh + mm;
  191. tc->start -= 2 * (tmins - tmins/10);
  192. }
  193. return 0;
  194. }