libavutil/timecode.h

   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 header
  25  */
  26
  27 #ifndef AVUTIL_TIMECODE_H
  28 #define AVUTIL_TIMECODE_H
  29
  30 #include <stdint.h>
  31 #include "rational.h"
  32
  33 #define AV_TIMECODE_STR_SIZE 23
  34
  35 enum AVTimecodeFlag {
  36     AV_TIMECODE_FLAG_DROPFRAME      = 1<<0, ///< timecode is drop frame
  37     AV_TIMECODE_FLAG_24HOURSMAX     = 1<<1, ///< timecode wraps after 24 hours
  38     AV_TIMECODE_FLAG_ALLOWNEGATIVE  = 1<<2, ///< negative time values are allowed
  39 };
  40
  41 typedef struct {
  42     int start;          ///< timecode frame start (first base frame number)
  43     uint32_t flags;     ///< flags such as drop frame, +24 hours support, ...
  44     AVRational rate;    ///< frame rate in rational form
  45     unsigned fps;       ///< frame per second; must be consistent with the rate field
  46 } AVTimecode;
  47
  48 /**
  49  * Adjust frame number for NTSC drop frame time code.
  50  *
  51  * @param framenum frame number to adjust
  52  * @param fps      frame per second, multiples of 30
  53  * @return         adjusted frame number
  54  * @warning        adjustment is only valid for multiples of NTSC 29.97
  55  */
  56 int av_timecode_adjust_ntsc_framenum2(int framenum, int fps);
  57
  58 /**
  59  * Convert frame number to SMPTE 12M binary representation.
  60  *
  61  * @param tc       timecode data correctly initialized
  62  * @param framenum frame number
  63  * @return         the SMPTE binary representation
  64  *
  65  * See SMPTE ST 314M-2005 Sec 4.4.2.2.1 "Time code pack (TC)"
  66  * the format description as follows:
  67  * bits 0-5:   hours, in BCD(6bits)
  68  * bits 6:     BGF1
  69  * bits 7:     BGF2 (NTSC) or FIELD (PAL)
  70  * bits 8-14:  minutes, in BCD(7bits)
  71  * bits 15:    BGF0 (NTSC) or BGF2 (PAL)
  72  * bits 16-22: seconds, in BCD(7bits)
  73  * bits 23:    FIELD (NTSC) or BGF0 (PAL)
  74  * bits 24-29: frames, in BCD(6bits)
  75  * bits 30:    drop  frame flag (0: non drop,    1: drop)
  76  * bits 31:    color frame flag (0: unsync mode, 1: sync mode)
  77  * @note BCD numbers (6 or 7 bits): 4 or 5 lower bits for units, 2 higher bits for tens.
  78  * @note Frame number adjustment is automatically done in case of drop timecode,
  79  *       you do NOT have to call av_timecode_adjust_ntsc_framenum2().
  80  * @note The frame number is relative to tc->start.
  81  * @note Color frame (CF) and binary group flags (BGF) bits are set to zero.
  82  */
  83 uint32_t av_timecode_get_smpte_from_framenum(const AVTimecode *tc, int framenum);
  84
  85 /**
  86  * Convert sei info to SMPTE 12M binary representation.
  87  *
  88  * @param rate     frame rate in rational form
  89  * @param drop     drop flag
  90  * @param hh       hour
  91  * @param mm       minute
  92  * @param ss       second
  93  * @param ff       frame number
  94  * @return         the SMPTE binary representation
  95  */
  96 uint32_t av_timecode_get_smpte(AVRational rate, int drop, int hh, int mm, int ss, int ff);
  97
  98 /**
  99  * Load timecode string in buf.
 100  *
 101  * @param tc       timecode data correctly initialized
 102  * @param buf      destination buffer, must be at least AV_TIMECODE_STR_SIZE long
 103  * @param framenum frame number
 104  * @return         the buf parameter
 105  *
 106  * @note Timecode representation can be a negative timecode and have more than
 107  *       24 hours, but will only be honored if the flags are correctly set.
 108  * @note The frame number is relative to tc->start.
 109  */
 110 char *av_timecode_make_string(const AVTimecode *tc, char *buf, int framenum);
 111
 112 /**
 113  * Get the timecode string from the SMPTE timecode format.
 114  *
 115  * In contrast to av_timecode_make_smpte_tc_string this function supports 50/60
 116  * fps timecodes by using the field bit.
 117  *
 118  * @param buf        destination buffer, must be at least AV_TIMECODE_STR_SIZE long
 119  * @param rate       frame rate of the timecode
 120  * @param tcsmpte    the 32-bit SMPTE timecode
 121  * @param prevent_df prevent the use of a drop flag when it is known the DF bit
 122  *                   is arbitrary
 123  * @param skip_field prevent the use of a field flag when it is known the field
 124  *                   bit is arbitrary (e.g. because it is used as PC flag)
 125  * @return           the buf parameter
 126  */
 127 char *av_timecode_make_smpte_tc_string2(char *buf, AVRational rate, uint32_t tcsmpte, int prevent_df, int skip_field);
 128
 129 /**
 130  * Get the timecode string from the SMPTE timecode format.
 131  *
 132  * @param buf        destination buffer, must be at least AV_TIMECODE_STR_SIZE long
 133  * @param tcsmpte    the 32-bit SMPTE timecode
 134  * @param prevent_df prevent the use of a drop flag when it is known the DF bit
 135  *                   is arbitrary
 136  * @return           the buf parameter
 137  */
 138 char *av_timecode_make_smpte_tc_string(char *buf, uint32_t tcsmpte, int prevent_df);
 139
 140 /**
 141  * Get the timecode string from the 25-bit timecode format (MPEG GOP format).
 142  *
 143  * @param buf     destination buffer, must be at least AV_TIMECODE_STR_SIZE long
 144  * @param tc25bit the 25-bits timecode
 145  * @return        the buf parameter
 146  */
 147 char *av_timecode_make_mpeg_tc_string(char *buf, uint32_t tc25bit);
 148
 149 /**
 150  * Init a timecode struct with the passed parameters.
 151  *
 152  * @param tc          pointer to an allocated AVTimecode
 153  * @param rate        frame rate in rational form
 154  * @param flags       miscellaneous flags such as drop frame, +24 hours, ...
 155  *                    (see AVTimecodeFlag)
 156  * @param frame_start the first frame number
 157  * @param log_ctx     a pointer to an arbitrary struct of which the first field
 158  *                    is a pointer to an AVClass struct (used for av_log)
 159  * @return            0 on success, AVERROR otherwise
 160  */
 161 int av_timecode_init(AVTimecode *tc, AVRational rate, int flags, int frame_start, void *log_ctx);
 162
 163 /**
 164  * Init a timecode struct from the passed timecode components.
 165  *
 166  * @param tc          pointer to an allocated AVTimecode
 167  * @param rate        frame rate in rational form
 168  * @param flags       miscellaneous flags such as drop frame, +24 hours, ...
 169  *                    (see AVTimecodeFlag)
 170  * @param hh          hours
 171  * @param mm          minutes
 172  * @param ss          seconds
 173  * @param ff          frames
 174  * @param log_ctx     a pointer to an arbitrary struct of which the first field
 175  *                    is a pointer to an AVClass struct (used for av_log)
 176  * @return            0 on success, AVERROR otherwise
 177  */
 178 int av_timecode_init_from_components(AVTimecode *tc, AVRational rate, int flags, int hh, int mm, int ss, int ff, void *log_ctx);
 179
 180 /**
 181  * Parse timecode representation (hh:mm:ss[:;.]ff).
 182  *
 183  * @param tc      pointer to an allocated AVTimecode
 184  * @param rate    frame rate in rational form
 185  * @param str     timecode string which will determine the frame start
 186  * @param log_ctx a pointer to an arbitrary struct of which the first field is a
 187  *                pointer to an AVClass struct (used for av_log).
 188  * @return        0 on success, AVERROR otherwise
 189  */
 190 int av_timecode_init_from_string(AVTimecode *tc, AVRational rate, const char *str, void *log_ctx);
 191
 192 /**
 193  * Check if the timecode feature is available for the given frame rate
 194  *
 195  * @return 0 if supported, <0 otherwise
 196  */
 197 int av_timecode_check_frame_rate(AVRational rate);
 198
 199 #endif /* AVUTIL_TIMECODE_H */