text: /*
   * Copyright (c) 2006 Smartjog S.A.S, Baptiste Coudurier <baptiste.coudurier@gmail.com>
   * Copyright (c) 2011-2012 Smartjog S.A.S, Clément Bœsch <clement.boesch@smartjog.com>
   *
   * This file is part of FFmpeg.
   *
   * FFmpeg is free software; you can redistribute it and/or
   * modify it under the terms of the GNU Lesser General Public
   * License as published by the Free Software Foundation; either
   * version 2.1 of the License, or (at your option) any later version.
   *
   * FFmpeg is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   * Lesser General Public License for more details.
   *
   * You should have received a copy of the GNU Lesser General Public
   * License along with FFmpeg; if not, write to the Free Software
   * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
   */
  
  /**
   * @file
   * Timecode helpers header
   */
  
  #ifndef AVUTIL_TIMECODE_H
  #define AVUTIL_TIMECODE_H
  
  #include <stdint.h>
  #include "rational.h"
  
  #define AV_TIMECODE_STR_SIZE 23
  
  enum AVTimecodeFlag {
      AV_TIMECODE_FLAG_DROPFRAME      = 1<<0, ///< timecode is drop frame
      AV_TIMECODE_FLAG_24HOURSMAX     = 1<<1, ///< timecode wraps after 24 hours
      AV_TIMECODE_FLAG_ALLOWNEGATIVE  = 1<<2, ///< negative time values are allowed
  };
  
  typedef struct {
      int start;          ///< timecode frame start (first base frame number)
      uint32_t flags;     ///< flags such as drop frame, +24 hours support, ...
      AVRational rate;    ///< frame rate in rational form
      unsigned fps;       ///< frame per second; must be consistent with the rate field
  } AVTimecode;
  
  /**
   * Adjust frame number for NTSC drop frame time code.
   *
   * @param framenum frame number to adjust
   * @param fps      frame per second, multiples of 30
   * @return         adjusted frame number
   * @warning        adjustment is only valid for multiples of NTSC 29.97
   */
  int av_timecode_adjust_ntsc_framenum2(int framenum, int fps);
  
  /**
   * Convert frame number to SMPTE 12M binary representation.
   *
   * @param tc       timecode data correctly initialized
   * @param framenum frame number
   * @return         the SMPTE binary representation
   *
   * See SMPTE ST 314M-2005 Sec 4.4.2.2.1 "Time code pack (TC)"
   * the format description as follows:
   * bits 0-5:   hours, in BCD(6bits)
   * bits 6:     BGF1
   * bits 7:     BGF2 (NTSC) or FIELD (PAL)
   * bits 8-14:  minutes, in BCD(7bits)
   * bits 15:    BGF0 (NTSC) or BGF2 (PAL)
   * bits 16-22: seconds, in BCD(7bits)
   * bits 23:    FIELD (NTSC) or BGF0 (PAL)
   * bits 24-29: frames, in BCD(6bits)
   * bits 30:    drop  frame flag (0: non drop,    1: drop)
   * bits 31:    color frame flag (0: unsync mode, 1: sync mode)
   * @note BCD numbers (6 or 7 bits): 4 or 5 lower bits for units, 2 higher bits for tens.
   * @note Frame number adjustment is automatically done in case of drop timecode,
   *       you do NOT have to call av_timecode_adjust_ntsc_framenum2().
   * @note The frame number is relative to tc->start.
   * @note Color frame (CF) and binary group flags (BGF) bits are set to zero.
   */
  uint32_t av_timecode_get_smpte_from_framenum(const AVTimecode *tc, int framenum);
  
  /**
   * Convert sei info to SMPTE 12M binary representation.
   *
   * @param rate     frame rate in rational form
   * @param drop     drop flag
   * @param hh       hour
   * @param mm       minute
   * @param ss       second
   * @param ff       frame number
   * @return         the SMPTE binary representation
   */
  uint32_t av_timecode_get_smpte(AVRational rate, int drop, int hh, int mm, int ss, int ff);
  
  /**
   * Load timecode string in buf.
   *
   * @param buf      destination buffer, must be at least AV_TIMECODE_STR_SIZE long
   * @param tc       timecode data correctly initialized
   * @param framenum frame number
   * @return         the buf parameter
   *
   * @note Timecode representation can be a negative timecode and have more than
   *       24 hours, but will only be honored if the flags are correctly set.
   * @note The frame number is relative to tc->start.
   */
  char *av_timecode_make_string(const AVTimecode *tc, char *buf, int framenum);
  
  /**
   * Get the timecode string from the SMPTE timecode format.
   *
   * In contrast to av_timecode_make_smpte_tc_string this function supports 50/60
   * fps timecodes by using the field bit.
   *
   * @param buf        destination buffer, must be at least AV_TIMECODE_STR_SIZE long
   * @param rate       frame rate of the timecode
   * @param tcsmpte    the 32-bit SMPTE timecode
   * @param prevent_df prevent the use of a drop flag when it is known the DF bit
   *                   is arbitrary
   * @param skip_field prevent the use of a field flag when it is known the field
   *                   bit is arbitrary (e.g. because it is used as PC flag)
   * @return           the buf parameter
   */
  char *av_timecode_make_smpte_tc_string2(char *buf, AVRational rate, uint32_t tcsmpte, int prevent_df, int skip_field);
  
  /**
   * Get the timecode string from the SMPTE timecode format.
   *
   * @param buf        destination buffer, must be at least AV_TIMECODE_STR_SIZE long
   * @param tcsmpte    the 32-bit SMPTE timecode
   * @param prevent_df prevent the use of a drop flag when it is known the DF bit
   *                   is arbitrary
   * @return           the buf parameter
   */
  char *av_timecode_make_smpte_tc_string(char *buf, uint32_t tcsmpte, int prevent_df);
  
  /**
   * Get the timecode string from the 25-bit timecode format (MPEG GOP format).
   *
   * @param buf     destination buffer, must be at least AV_TIMECODE_STR_SIZE long
   * @param tc25bit the 25-bits timecode
   * @return        the buf parameter
   */
  char *av_timecode_make_mpeg_tc_string(char *buf, uint32_t tc25bit);
  
  /**
   * Init a timecode struct with the passed parameters.
   *
   * @param log_ctx     a pointer to an arbitrary struct of which the first field
   *                    is a pointer to an AVClass struct (used for av_log)
   * @param tc          pointer to an allocated AVTimecode
   * @param rate        frame rate in rational form
   * @param flags       miscellaneous flags such as drop frame, +24 hours, ...
   *                    (see AVTimecodeFlag)
   * @param frame_start the first frame number
   * @return            0 on success, AVERROR otherwise
   */
  int av_timecode_init(AVTimecode *tc, AVRational rate, int flags, int frame_start, void *log_ctx);
  
  /**
   * Init a timecode struct from the passed timecode components.
   *
   * @param log_ctx     a pointer to an arbitrary struct of which the first field
   *                    is a pointer to an AVClass struct (used for av_log)
   * @param tc          pointer to an allocated AVTimecode
   * @param rate        frame rate in rational form
   * @param flags       miscellaneous flags such as drop frame, +24 hours, ...
   *                    (see AVTimecodeFlag)
   * @param hh          hours
   * @param mm          minutes
   * @param ss          seconds
   * @param ff          frames
   * @return            0 on success, AVERROR otherwise
   */
  int av_timecode_init_from_components(AVTimecode *tc, AVRational rate, int flags, int hh, int mm, int ss, int ff, void *log_ctx);
  
  /**
   * Parse timecode representation (hh:mm:ss[:;.]ff).
   *
   * @param log_ctx a pointer to an arbitrary struct of which the first field is a
   *                pointer to an AVClass struct (used for av_log).
   * @param tc      pointer to an allocated AVTimecode
   * @param rate    frame rate in rational form
   * @param str     timecode string which will determine the frame start
   * @return        0 on success, AVERROR otherwise
   */
  int av_timecode_init_from_string(AVTimecode *tc, AVRational rate, const char *str, void *log_ctx);
  
  /**
   * Check if the timecode feature is available for the given frame rate
   *
   * @return 0 if supported, <0 otherwise
   */
  int av_timecode_check_frame_rate(AVRational rate);
  
  #endif /* AVUTIL_TIMECODE_H */
  