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timecode.c
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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
25  * @see https://en.wikipedia.org/wiki/SMPTE_time_code
26  * @see http://www.dropframetimecode.org
27  */
28 
29 #include <stdio.h>
30 #include "timecode.h"
31 #include "log.h"
32 #include "error.h"
33 
34 int av_timecode_adjust_ntsc_framenum2(int framenum, int fps)
35 {
36  /* only works for NTSC 29.97 and 59.94 */
37  int drop_frames = 0;
38  int d, m, frames_per_10mins;
39 
40  if (fps == 30) {
41  drop_frames = 2;
42  frames_per_10mins = 17982;
43  } else if (fps == 60) {
44  drop_frames = 4;
45  frames_per_10mins = 35964;
46  } else
47  return framenum;
48 
49  d = framenum / frames_per_10mins;
50  m = framenum % frames_per_10mins;
51 
52  return framenum + 9 * drop_frames * d + drop_frames * ((m - drop_frames) / (frames_per_10mins / 10));
53 }
54 
55 uint32_t av_timecode_get_smpte_from_framenum(const AVTimecode *tc, int framenum)
56 {
57  unsigned fps = tc->fps;
58  int drop = !!(tc->flags & AV_TIMECODE_FLAG_DROPFRAME);
59  int hh, mm, ss, ff;
60 
61  framenum += tc->start;
62  if (drop)
63  framenum = av_timecode_adjust_ntsc_framenum2(framenum, tc->fps);
64  ff = framenum % fps;
65  ss = framenum / fps % 60;
66  mm = framenum / (fps*60) % 60;
67  hh = framenum / (fps*3600) % 24;
68  return 0 << 31 | // color frame flag (0: unsync mode, 1: sync mode)
69  drop << 30 | // drop frame flag (0: non drop, 1: drop)
70  (ff / 10) << 28 | // tens of frames
71  (ff % 10) << 24 | // units of frames
72  0 << 23 | // PC (NTSC) or BGF0 (PAL)
73  (ss / 10) << 20 | // tens of seconds
74  (ss % 10) << 16 | // units of seconds
75  0 << 15 | // BGF0 (NTSC) or BGF2 (PAL)
76  (mm / 10) << 12 | // tens of minutes
77  (mm % 10) << 8 | // units of minutes
78  0 << 7 | // BGF2 (NTSC) or PC (PAL)
79  0 << 6 | // BGF1
80  (hh / 10) << 4 | // tens of hours
81  (hh % 10); // units of hours
82 }
83 
84 char *av_timecode_make_string(const AVTimecode *tc, char *buf, int framenum)
85 {
86  int fps = tc->fps;
87  int drop = tc->flags & AV_TIMECODE_FLAG_DROPFRAME;
88  int hh, mm, ss, ff, neg = 0;
89 
90  framenum += tc->start;
91  if (drop)
92  framenum = av_timecode_adjust_ntsc_framenum2(framenum, fps);
93  if (framenum < 0) {
94  framenum = -framenum;
96  }
97  ff = framenum % fps;
98  ss = framenum / fps % 60;
99  mm = framenum / (fps*60) % 60;
100  hh = framenum / (fps*3600);
102  hh = hh % 24;
103  snprintf(buf, AV_TIMECODE_STR_SIZE, "%s%02d:%02d:%02d%c%02d",
104  neg ? "-" : "",
105  hh, mm, ss, drop ? ';' : ':', ff);
106  return buf;
107 }
108 
109 static unsigned bcd2uint(uint8_t bcd)
110 {
111  unsigned low = bcd & 0xf;
112  unsigned high = bcd >> 4;
113  if (low > 9 || high > 9)
114  return 0;
115  return low + 10*high;
116 }
117 
118 char *av_timecode_make_smpte_tc_string(char *buf, uint32_t tcsmpte, int prevent_df)
119 {
120  unsigned hh = bcd2uint(tcsmpte & 0x3f); // 6-bit hours
121  unsigned mm = bcd2uint(tcsmpte>>8 & 0x7f); // 7-bit minutes
122  unsigned ss = bcd2uint(tcsmpte>>16 & 0x7f); // 7-bit seconds
123  unsigned ff = bcd2uint(tcsmpte>>24 & 0x3f); // 6-bit frames
124  unsigned drop = tcsmpte & 1<<30 && !prevent_df; // 1-bit drop if not arbitrary bit
125  snprintf(buf, AV_TIMECODE_STR_SIZE, "%02u:%02u:%02u%c%02u",
126  hh, mm, ss, drop ? ';' : ':', ff);
127  return buf;
128 }
129 
130 char *av_timecode_make_mpeg_tc_string(char *buf, uint32_t tc25bit)
131 {
133  "%02"PRIu32":%02"PRIu32":%02"PRIu32"%c%02"PRIu32,
134  tc25bit>>19 & 0x1f, // 5-bit hours
135  tc25bit>>13 & 0x3f, // 6-bit minutes
136  tc25bit>>6 & 0x3f, // 6-bit seconds
137  tc25bit & 1<<24 ? ';' : ':', // 1-bit drop flag
138  tc25bit & 0x3f); // 6-bit frames
139  return buf;
140 }
141 
142 static int check_fps(int fps)
143 {
144  int i;
145  static const int supported_fps[] = {
146  24, 25, 30, 48, 50, 60, 100, 120, 150,
147  };
148 
149  for (i = 0; i < FF_ARRAY_ELEMS(supported_fps); i++)
150  if (fps == supported_fps[i])
151  return 0;
152  return -1;
153 }
154 
155 static int check_timecode(void *log_ctx, AVTimecode *tc)
156 {
157  if ((int)tc->fps <= 0) {
158  av_log(log_ctx, AV_LOG_ERROR, "Valid timecode frame rate must be specified. Minimum value is 1\n");
159  return AVERROR(EINVAL);
160  }
161  if ((tc->flags & AV_TIMECODE_FLAG_DROPFRAME) && tc->fps != 30 && tc->fps != 60) {
162  av_log(log_ctx, AV_LOG_ERROR, "Drop frame is only allowed with 30000/1001 or 60000/1001 FPS\n");
163  return AVERROR(EINVAL);
164  }
165  if (check_fps(tc->fps) < 0) {
166  av_log(log_ctx, AV_LOG_WARNING, "Using non-standard frame rate %d/%d\n",
167  tc->rate.num, tc->rate.den);
168  }
169  return 0;
170 }
171 
173 {
174  if (!rate.den || !rate.num)
175  return -1;
176  return (rate.num + rate.den/2) / rate.den;
177 }
178 
180 {
181  return check_fps(fps_from_frame_rate(rate));
182 }
183 
184 int av_timecode_init(AVTimecode *tc, AVRational rate, int flags, int frame_start, void *log_ctx)
185 {
186  memset(tc, 0, sizeof(*tc));
187  tc->start = frame_start;
188  tc->flags = flags;
189  tc->rate = rate;
190  tc->fps = fps_from_frame_rate(rate);
191  return check_timecode(log_ctx, tc);
192 }
193 
194 int av_timecode_init_from_string(AVTimecode *tc, AVRational rate, const char *str, void *log_ctx)
195 {
196  char c;
197  int hh, mm, ss, ff, ret;
198 
199  if (sscanf(str, "%d:%d:%d%c%d", &hh, &mm, &ss, &c, &ff) != 5) {
200  av_log(log_ctx, AV_LOG_ERROR, "Unable to parse timecode, "
201  "syntax: hh:mm:ss[:;.]ff\n");
202  return AVERROR_INVALIDDATA;
203  }
204 
205  memset(tc, 0, sizeof(*tc));
206  tc->flags = c != ':' ? AV_TIMECODE_FLAG_DROPFRAME : 0; // drop if ';', '.', ...
207  tc->rate = rate;
208  tc->fps = fps_from_frame_rate(rate);
209 
210  ret = check_timecode(log_ctx, tc);
211  if (ret < 0)
212  return ret;
213 
214  tc->start = (hh*3600 + mm*60 + ss) * tc->fps + ff;
215  if (tc->flags & AV_TIMECODE_FLAG_DROPFRAME) { /* adjust frame number */
216  int tmins = 60*hh + mm;
217  tc->start -= (tc->fps == 30 ? 2 : 4) * (tmins - tmins/10);
218  }
219  return 0;
220 }
#define AVERROR_INVALIDDATA
Invalid data found when processing input.
Definition: error.h:59
#define AV_LOG_WARNING
Something somehow does not look correct.
Definition: log.h:182
int num
Numerator.
Definition: rational.h:59
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
#define tc
Definition: regdef.h:69
static int check_timecode(void *log_ctx, AVTimecode *tc)
Definition: timecode.c:155
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
static unsigned bcd2uint(uint8_t bcd)
Definition: timecode.c:109
uint8_t
timecode is drop frame
Definition: timecode.h:36
int start
timecode frame start (first base frame number)
Definition: timecode.h:42
#define av_log(a,...)
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 check_fps(int fps)
Definition: timecode.c:142
#define AV_LOG_ERROR
Something went wrong and cannot losslessly be recovered.
Definition: log.h:176
error code definitions
#define AVERROR(e)
Definition: error.h:43
unsigned fps
frame per second; must be consistent with the rate field
Definition: timecode.h:45
#define ss(width, name, subs,...)
Definition: cbs_vp9.c:261
#define FF_ARRAY_ELEMS(a)
int av_timecode_adjust_ntsc_framenum2(int framenum, int fps)
Adjust frame number for NTSC drop frame time code.
Definition: timecode.c:34
Timecode helpers header.
timecode wraps after 24 hours
Definition: timecode.h:37
AVRational rate
frame rate in rational form
Definition: timecode.h:44
static int frame_start(MpegEncContext *s)
void * buf
Definition: avisynth_c.h:690
Rational number (pair of numerator and denominator).
Definition: rational.h:58
#define snprintf
Definition: snprintf.h:34
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
#define flags(name, subs,...)
Definition: cbs_av1.c:596
static int fps_from_frame_rate(AVRational rate)
Definition: timecode.c:172
char * av_timecode_make_string(const AVTimecode *tc, char *buf, int framenum)
Load timecode string in buf.
Definition: timecode.c:84
negative time values are allowed
Definition: timecode.h:38
if(ret< 0)
Definition: vf_mcdeint.c:279
static double c[64]
int den
Denominator.
Definition: rational.h:60
int av_timecode_check_frame_rate(AVRational rate)
Check if the timecode feature is available for the given frame rate.
Definition: timecode.c:179
uint32_t flags
flags such as drop frame, +24 hours support, ...
Definition: timecode.h:43
#define AV_TIMECODE_STR_SIZE
Definition: timecode.h:33
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