FFmpeg
timecode.h
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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 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 
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, 30 or 60
53  * @return adjusted frame number
54  * @warning adjustment is only valid in NTSC 29.97 and 59.94
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  * @note Frame number adjustment is automatically done in case of drop timecode,
66  * you do NOT have to call av_timecode_adjust_ntsc_framenum2().
67  * @note The frame number is relative to tc->start.
68  * @note Color frame (CF), binary group flags (BGF) and biphase mark polarity
69  * correction (PC) bits are set to zero.
70  */
71 uint32_t av_timecode_get_smpte_from_framenum(const AVTimecode *tc, int framenum);
72 
73 /**
74  * Load timecode string in buf.
75  *
76  * @param buf destination buffer, must be at least AV_TIMECODE_STR_SIZE long
77  * @param tc timecode data correctly initialized
78  * @param framenum frame number
79  * @return the buf parameter
80  *
81  * @note Timecode representation can be a negative timecode and have more than
82  * 24 hours, but will only be honored if the flags are correctly set.
83  * @note The frame number is relative to tc->start.
84  */
85 char *av_timecode_make_string(const AVTimecode *tc, char *buf, int framenum);
86 
87 /**
88  * Get the timecode string from the SMPTE timecode format.
89  *
90  * @param buf destination buffer, must be at least AV_TIMECODE_STR_SIZE long
91  * @param tcsmpte the 32-bit SMPTE timecode
92  * @param prevent_df prevent the use of a drop flag when it is known the DF bit
93  * is arbitrary
94  * @return the buf parameter
95  */
96 char *av_timecode_make_smpte_tc_string(char *buf, uint32_t tcsmpte, int prevent_df);
97 
98 /**
99  * Get the timecode string from the 25-bit timecode format (MPEG GOP format).
100  *
101  * @param buf destination buffer, must be at least AV_TIMECODE_STR_SIZE long
102  * @param tc25bit the 25-bits timecode
103  * @return the buf parameter
104  */
105 char *av_timecode_make_mpeg_tc_string(char *buf, uint32_t tc25bit);
106 
107 /**
108  * Init a timecode struct with the passed parameters.
109  *
110  * @param log_ctx a pointer to an arbitrary struct of which the first field
111  * is a pointer to an AVClass struct (used for av_log)
112  * @param tc pointer to an allocated AVTimecode
113  * @param rate frame rate in rational form
114  * @param flags miscellaneous flags such as drop frame, +24 hours, ...
115  * (see AVTimecodeFlag)
116  * @param frame_start the first frame number
117  * @return 0 on success, AVERROR otherwise
118  */
119 int av_timecode_init(AVTimecode *tc, AVRational rate, int flags, int frame_start, void *log_ctx);
120 
121 /**
122  * Parse timecode representation (hh:mm:ss[:;.]ff).
123  *
124  * @param log_ctx a pointer to an arbitrary struct of which the first field is a
125  * pointer to an AVClass struct (used for av_log).
126  * @param tc pointer to an allocated AVTimecode
127  * @param rate frame rate in rational form
128  * @param str timecode string which will determine the frame start
129  * @return 0 on success, AVERROR otherwise
130  */
131 int av_timecode_init_from_string(AVTimecode *tc, AVRational rate, const char *str, void *log_ctx);
132 
133 /**
134  * Check if the timecode feature is available for the given frame rate
135  *
136  * @return 0 if supported, <0 otherwise
137  */
139 
140 #endif /* AVUTIL_TIMECODE_H */
#define tc
Definition: regdef.h:69
timecode is drop frame
Definition: timecode.h:36
char * av_timecode_make_string(const AVTimecode *tc, char *buf, int framenum)
Load timecode string in buf.
Definition: timecode.c:84
int start
timecode frame start (first base frame number)
Definition: timecode.h:42
int av_timecode_init_from_string(AVTimecode *tc, AVRational rate, const char *str, void *log_ctx)
Parse timecode representation (hh:mm:ss[:;.
Definition: timecode.c:194
AVTimecodeFlag
Definition: timecode.h:35
unsigned fps
frame per second; must be consistent with the rate field
Definition: timecode.h:45
timecode wraps after 24 hours
Definition: timecode.h:37
int av_timecode_adjust_ntsc_framenum2(int framenum, int fps)
Adjust frame number for NTSC drop frame time code.
Definition: timecode.c:34
AVRational rate
frame rate in rational form
Definition: timecode.h:44
int av_timecode_init(AVTimecode *tc, AVRational rate, int flags, int frame_start, void *log_ctx)
Init a timecode struct with the passed parameters.
Definition: timecode.c:184
static int frame_start(MpegEncContext *s)
void * buf
Definition: avisynth_c.h:766
Rational number (pair of numerator and denominator).
Definition: rational.h:58
int av_timecode_check_frame_rate(AVRational rate)
Check if the timecode feature is available for the given frame rate.
Definition: timecode.c:179
#define flags(name, subs,...)
Definition: cbs_av1.c:561
negative time values are allowed
Definition: timecode.h:38
char * av_timecode_make_smpte_tc_string(char *buf, uint32_t tcsmpte, int prevent_df)
Get the timecode string from the SMPTE timecode format.
Definition: timecode.c:118
char * av_timecode_make_mpeg_tc_string(char *buf, uint32_t tc25bit)
Get the timecode string from the 25-bit timecode format (MPEG GOP format).
Definition: timecode.c:130
Utilties for rational number calculation.
uint32_t av_timecode_get_smpte_from_framenum(const AVTimecode *tc, int framenum)
Convert frame number to SMPTE 12M binary representation.
Definition: timecode.c:55
uint32_t flags
flags such as drop frame, +24 hours support, ...
Definition: timecode.h:43