libavutil/timecode.c

   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 "common.h"
  31 #include "timecode.h"
  32 #include "log.h"
  33 #include "error.h"
  34
  35 int av_timecode_adjust_ntsc_framenum2(int framenum, int fps)
  36 {
  37     /* only works for multiples of NTSC 29.97 */
  38     int drop_frames = 0;
  39     int d, m, frames_per_10mins;
  40
  41     if (fps && fps % 30 == 0) {
  42         drop_frames = fps / 30 * 2;
  43         frames_per_10mins = fps / 30 * 17982;
  44     } else
  45         return framenum;
  46
  47     d = framenum / frames_per_10mins;
  48     m = framenum % frames_per_10mins;
  49
  50     return framenum + 9U * drop_frames * d + drop_frames * ((m - drop_frames) / (frames_per_10mins / 10));
  51 }
  52
  53 uint32_t av_timecode_get_smpte_from_framenum(const AVTimecode *tc, int framenum)
  54 {
  55     unsigned fps = tc->fps;
  56     int drop = !!(tc->flags & AV_TIMECODE_FLAG_DROPFRAME);
  57     int hh, mm, ss, ff;
  58
  59     framenum += tc->start;
  60     if (drop)
  61         framenum = av_timecode_adjust_ntsc_framenum2(framenum, tc->fps);
  62     ff = framenum % fps;
  63     ss = framenum / fps      % 60;
  64     mm = framenum / (fps*60LL) % 60;
  65     hh = framenum / (fps*3600LL) % 24;
  66     return av_timecode_get_smpte(tc->rate, drop, hh, mm, ss, ff);
  67 }
  68
  69 uint32_t av_timecode_get_smpte(AVRational rate, int drop, int hh, int mm, int ss, int ff)
  70 {
  71     uint32_t tc = 0;
  72
  73     /* For SMPTE 12-M timecodes, frame count is a special case if > 30 FPS.
  74        See SMPTE ST 12-1:2014 Sec 12.1 for more info. */
  75     if (av_cmp_q(rate, (AVRational) {30, 1}) == 1) {
  76         if (ff % 2 == 1) {
  77             if (av_cmp_q(rate, (AVRational) {50, 1}) == 0)
  78                 tc |= (1 << 7);
  79             else
  80                 tc |= (1 << 23);
  81         }
  82         ff /= 2;
  83     }
  84
  85     hh = hh % 24;
  86     mm = av_clip(mm, 0, 59);
  87     ss = av_clip(ss, 0, 59);
  88     ff = ff % 40;
  89
  90     tc |= drop << 30;
  91     tc |= (ff / 10) << 28;
  92     tc |= (ff % 10) << 24;
  93     tc |= (ss / 10) << 20;
  94     tc |= (ss % 10) << 16;
  95     tc |= (mm / 10) << 12;
  96     tc |= (mm % 10) << 8;
  97     tc |= (hh / 10) << 4;
  98     tc |= (hh % 10);
  99
 100     return tc;
 101 }
 102
 103 char *av_timecode_make_string(const AVTimecode *tc, char *buf, int framenum_arg)
 104 {
 105     int fps = tc->fps;
 106     int drop = tc->flags & AV_TIMECODE_FLAG_DROPFRAME;
 107     int hh, mm, ss, ff, ff_len, neg = 0;
 108     int64_t framenum = framenum_arg;
 109
 110     framenum += tc->start;
 111     if (drop)
 112         framenum = av_timecode_adjust_ntsc_framenum2(framenum, fps);
 113     if (framenum < 0) {
 114         framenum = -framenum;
 115         neg = tc->flags & AV_TIMECODE_FLAG_ALLOWNEGATIVE;
 116     }
 117     ff = framenum % fps;
 118     ss = framenum / fps        % 60;
 119     mm = framenum / (fps*60LL) % 60;
 120     hh = framenum / (fps*3600LL);
 121     if (tc->flags & AV_TIMECODE_FLAG_24HOURSMAX)
 122         hh = hh % 24;
 123     ff_len = fps > 10000 ? 5 : fps > 1000 ? 4 : fps > 100 ? 3 : fps > 10 ? 2 : 1;
 124     snprintf(buf, AV_TIMECODE_STR_SIZE, "%s%02d:%02d:%02d%c%0*d",
 125              neg ? "-" : "",
 126              hh, mm, ss, drop ? ';' : ':', ff_len, ff);
 127     return buf;
 128 }
 129
 130 static unsigned bcd2uint(uint8_t bcd)
 131 {
 132    unsigned low  = bcd & 0xf;
 133    unsigned high = bcd >> 4;
 134    if (low > 9 || high > 9)
 135        return 0;
 136    return low + 10*high;
 137 }
 138
 139 char *av_timecode_make_smpte_tc_string2(char *buf, AVRational rate, uint32_t tcsmpte, int prevent_df, int skip_field)
 140 {
 141     unsigned hh   = bcd2uint(tcsmpte     & 0x3f);    // 6-bit hours
 142     unsigned mm   = bcd2uint(tcsmpte>>8  & 0x7f);    // 7-bit minutes
 143     unsigned ss   = bcd2uint(tcsmpte>>16 & 0x7f);    // 7-bit seconds
 144     unsigned ff   = bcd2uint(tcsmpte>>24 & 0x3f);    // 6-bit frames
 145     unsigned drop = tcsmpte & 1<<30 && !prevent_df;  // 1-bit drop if not arbitrary bit
 146
 147     if (av_cmp_q(rate, (AVRational) {30, 1}) == 1) {
 148         ff <<= 1;
 149         if (!skip_field) {
 150             if (av_cmp_q(rate, (AVRational) {50, 1}) == 0)
 151                 ff += !!(tcsmpte & 1 << 7);
 152             else
 153                 ff += !!(tcsmpte & 1 << 23);
 154         }
 155     }
 156
 157     snprintf(buf, AV_TIMECODE_STR_SIZE, "%02u:%02u:%02u%c%02u",
 158              hh, mm, ss, drop ? ';' : ':', ff);
 159     return buf;
 160
 161 }
 162
 163 char *av_timecode_make_smpte_tc_string(char *buf, uint32_t tcsmpte, int prevent_df)
 164 {
 165     return av_timecode_make_smpte_tc_string2(buf, (AVRational){30, 1}, tcsmpte, prevent_df, 1);
 166 }
 167
 168 char *av_timecode_make_mpeg_tc_string(char *buf, uint32_t tc25bit)
 169 {
 170     snprintf(buf, AV_TIMECODE_STR_SIZE,
 171              "%02"PRIu32":%02"PRIu32":%02"PRIu32"%c%02"PRIu32,
 172              tc25bit>>19 & 0x1f,              // 5-bit hours
 173              tc25bit>>13 & 0x3f,              // 6-bit minutes
 174              tc25bit>>6  & 0x3f,              // 6-bit seconds
 175              tc25bit     & 1<<24 ? ';' : ':', // 1-bit drop flag
 176              tc25bit     & 0x3f);             // 6-bit frames
 177     return buf;
 178 }
 179
 180 static int check_fps(int fps)
 181 {
 182     int i;
 183     static const int supported_fps[] = {
 184         24, 25, 30, 48, 50, 60, 100, 120, 150,
 185     };
 186
 187     for (i = 0; i < FF_ARRAY_ELEMS(supported_fps); i++)
 188         if (fps == supported_fps[i])
 189             return 0;
 190     return -1;
 191 }
 192
 193 static int check_timecode(void *log_ctx, AVTimecode *tc)
 194 {
 195     if ((int)tc->fps <= 0) {
 196         av_log(log_ctx, AV_LOG_ERROR, "Valid timecode frame rate must be specified. Minimum value is 1\n");
 197         return AVERROR(EINVAL);
 198     }
 199     if ((tc->flags & AV_TIMECODE_FLAG_DROPFRAME) && tc->fps % 30 != 0) {
 200         av_log(log_ctx, AV_LOG_ERROR, "Drop frame is only allowed with multiples of 30000/1001 FPS\n");
 201         return AVERROR(EINVAL);
 202     }
 203     if (check_fps(tc->fps) < 0) {
 204         av_log(log_ctx, AV_LOG_WARNING, "Using non-standard frame rate %d/%d\n",
 205                tc->rate.num, tc->rate.den);
 206     }
 207     return 0;
 208 }
 209
 210 static int fps_from_frame_rate(AVRational rate)
 211 {
 212     if (!rate.den || !rate.num)
 213         return -1;
 214     return (rate.num + rate.den/2LL) / rate.den;
 215 }
 216
 217 int av_timecode_check_frame_rate(AVRational rate)
 218 {
 219     return check_fps(fps_from_frame_rate(rate));
 220 }
 221
 222 int av_timecode_init(AVTimecode *tc, AVRational rate, int flags, int frame_start, void *log_ctx)
 223 {
 224     memset(tc, 0, sizeof(*tc));
 225     tc->start = frame_start;
 226     tc->flags = flags;
 227     tc->rate  = rate;
 228     tc->fps   = fps_from_frame_rate(rate);
 229     return check_timecode(log_ctx, tc);
 230 }
 231
 232 int av_timecode_init_from_components(AVTimecode *tc, AVRational rate, int flags, int hh, int mm, int ss, int ff, void *log_ctx)
 233 {
 234     int ret;
 235
 236     memset(tc, 0, sizeof(*tc));
 237     tc->flags = flags;
 238     tc->rate  = rate;
 239     tc->fps   = fps_from_frame_rate(rate);
 240
 241     ret = check_timecode(log_ctx, tc);
 242     if (ret < 0)
 243         return ret;
 244
 245     tc->start = (hh*3600 + mm*60 + ss) * tc->fps + ff;
 246     if (tc->flags & AV_TIMECODE_FLAG_DROPFRAME) { /* adjust frame number */
 247         int tmins = 60*hh + mm;
 248         tc->start -= (tc->fps / 30 * 2) * (tmins - tmins/10);
 249     }
 250     return 0;
 251 }
 252
 253 int av_timecode_init_from_string(AVTimecode *tc, AVRational rate, const char *str, void *log_ctx)
 254 {
 255     char c;
 256     int hh, mm, ss, ff, flags;
 257
 258     if (sscanf(str, "%d:%d:%d%c%d", &hh, &mm, &ss, &c, &ff) != 5) {
 259         av_log(log_ctx, AV_LOG_ERROR, "Unable to parse timecode, "
 260                                       "syntax: hh:mm:ss[:;.]ff\n");
 261         return AVERROR_INVALIDDATA;
 262     }
 263     flags = c != ':' ? AV_TIMECODE_FLAG_DROPFRAME : 0; // drop if ';', '.', ...
 264
 265     return av_timecode_init_from_components(tc, rate, flags, hh, mm, ss, ff, log_ctx);
 266 }