FFmpeg
vf_fps.c
Go to the documentation of this file.
1 /*
2  * Copyright 2007 Bobby Bingham
3  * Copyright 2012 Robert Nagy <ronag89 gmail com>
4  * Copyright 2012 Anton Khirnov <anton khirnov net>
5  * Copyright 2018 Calvin Walton <calvin.walton@kepstin.ca>
6  *
7  * This file is part of FFmpeg.
8  *
9  * FFmpeg is free software; you can redistribute it and/or
10  * modify it under the terms of the GNU Lesser General Public
11  * License as published by the Free Software Foundation; either
12  * version 2.1 of the License, or (at your option) any later version.
13  *
14  * FFmpeg is distributed in the hope that it will be useful,
15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
17  * Lesser General Public License for more details.
18  *
19  * You should have received a copy of the GNU Lesser General Public
20  * License along with FFmpeg; if not, write to the Free Software
21  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
22  */
23 
24 /**
25  * @file
26  * a filter enforcing given constant framerate
27  */
28 
29 #include <float.h>
30 #include <stdint.h>
31 
32 #include "libavutil/avassert.h"
33 #include "libavutil/eval.h"
34 #include "libavutil/mathematics.h"
35 #include "libavutil/opt.h"
36 #include "avfilter.h"
37 #include "filters.h"
38 #include "internal.h"
39 
40 enum EOFAction {
44 };
45 
46 static const char *const var_names[] = {
47  "source_fps",
48  "ntsc",
49  "pal",
50  "film",
51  "ntsc_film",
52  NULL
53 };
54 
55 enum var_name {
62 };
63 
64 static const double ntsc_fps = 30000.0 / 1001.0;
65 static const double pal_fps = 25.0;
66 static const double film_fps = 24.0;
67 static const double ntsc_film_fps = 24000.0 / 1001.0;
68 
69 typedef struct FPSContext {
70  const AVClass *class;
71 
72  double start_time; ///< pts, in seconds, of the expected first frame
73 
74  char *framerate; ///< expression that defines the target framerate
75  int rounding; ///< AVRounding method for timestamps
76  int eof_action; ///< action performed for last frame in FIFO
77 
78  /* Set during outlink configuration */
79  int64_t in_pts_off; ///< input frame pts offset for start_time handling
80  int64_t out_pts_off; ///< output frame pts offset for start_time handling
81 
82  /* Runtime state */
83  int status; ///< buffered input status
84  int64_t status_pts; ///< buffered input status timestamp
85 
86  AVFrame *frames[2]; ///< buffered frames
87  int frames_count; ///< number of buffered frames
88 
89  int64_t next_pts; ///< pts of the next frame to output
90 
91  /* statistics */
92  int cur_frame_out; ///< number of times current frame has been output
93  int frames_in; ///< number of frames on input
94  int frames_out; ///< number of frames on output
95  int dup; ///< number of frames duplicated
96  int drop; ///< number of framed dropped
97 } FPSContext;
98 
99 #define OFFSET(x) offsetof(FPSContext, x)
100 #define V AV_OPT_FLAG_VIDEO_PARAM
101 #define F AV_OPT_FLAG_FILTERING_PARAM
102 static const AVOption fps_options[] = {
103  { "fps", "A string describing desired output framerate", OFFSET(framerate), AV_OPT_TYPE_STRING, { .str = "25" }, 0, 0, V|F },
104  { "start_time", "Assume the first PTS should be this value.", OFFSET(start_time), AV_OPT_TYPE_DOUBLE, { .dbl = DBL_MAX}, -DBL_MAX, DBL_MAX, V|F },
105  { "round", "set rounding method for timestamps", OFFSET(rounding), AV_OPT_TYPE_INT, { .i64 = AV_ROUND_NEAR_INF }, 0, 5, V|F, "round" },
106  { "zero", "round towards 0", 0, AV_OPT_TYPE_CONST, { .i64 = AV_ROUND_ZERO }, 0, 0, V|F, "round" },
107  { "inf", "round away from 0", 0, AV_OPT_TYPE_CONST, { .i64 = AV_ROUND_INF }, 0, 0, V|F, "round" },
108  { "down", "round towards -infty", 0, AV_OPT_TYPE_CONST, { .i64 = AV_ROUND_DOWN }, 0, 0, V|F, "round" },
109  { "up", "round towards +infty", 0, AV_OPT_TYPE_CONST, { .i64 = AV_ROUND_UP }, 0, 0, V|F, "round" },
110  { "near", "round to nearest", 0, AV_OPT_TYPE_CONST, { .i64 = AV_ROUND_NEAR_INF }, 0, 0, V|F, "round" },
111  { "eof_action", "action performed for last frame", OFFSET(eof_action), AV_OPT_TYPE_INT, { .i64 = EOF_ACTION_ROUND }, 0, EOF_ACTION_NB-1, V|F, "eof_action" },
112  { "round", "round similar to other frames", 0, AV_OPT_TYPE_CONST, { .i64 = EOF_ACTION_ROUND }, 0, 0, V|F, "eof_action" },
113  { "pass", "pass through last frame", 0, AV_OPT_TYPE_CONST, { .i64 = EOF_ACTION_PASS }, 0, 0, V|F, "eof_action" },
114  { NULL }
115 };
116 
118 
120 {
121  FPSContext *s = ctx->priv;
122 
123  s->status_pts = AV_NOPTS_VALUE;
124  s->next_pts = AV_NOPTS_VALUE;
125 
126  return 0;
127 }
128 
129 /* Remove the first frame from the buffer, returning it */
131 {
132  AVFrame *frame;
133 
134  /* Must only be called when there are frames in the buffer */
135  av_assert1(s->frames_count > 0);
136 
137  frame = s->frames[0];
138  s->frames[0] = s->frames[1];
139  s->frames[1] = NULL;
140  s->frames_count--;
141 
142  /* Update statistics counters */
143  s->frames_out += s->cur_frame_out;
144  if (s->cur_frame_out > 1) {
145  av_log(ctx, AV_LOG_DEBUG, "Duplicated frame with pts %"PRId64" %d times\n",
146  frame->pts, s->cur_frame_out - 1);
147  s->dup += s->cur_frame_out - 1;
148  } else if (s->cur_frame_out == 0) {
149  av_log(ctx, AV_LOG_DEBUG, "Dropping frame with pts %"PRId64"\n",
150  frame->pts);
151  s->drop++;
152  }
153  s->cur_frame_out = 0;
154 
155  return frame;
156 }
157 
159 {
160  FPSContext *s = ctx->priv;
161 
162  AVFrame *frame;
163 
164  while (s->frames_count > 0) {
165  frame = shift_frame(ctx, s);
167  }
168 
169  av_log(ctx, AV_LOG_VERBOSE, "%d frames in, %d frames out; %d frames dropped, "
170  "%d frames duplicated.\n", s->frames_in, s->frames_out, s->drop, s->dup);
171 }
172 
173 static int config_props(AVFilterLink* outlink)
174 {
175  AVFilterContext *ctx = outlink->src;
176  AVFilterLink *inlink = ctx->inputs[0];
177  FPSContext *s = ctx->priv;
178 
179  double var_values[VARS_NB], res;
180  int ret;
181 
182  var_values[VAR_SOURCE_FPS] = av_q2d(inlink->frame_rate);
183  var_values[VAR_FPS_NTSC] = ntsc_fps;
184  var_values[VAR_FPS_PAL] = pal_fps;
185  var_values[VAR_FPS_FILM] = film_fps;
186  var_values[VAR_FPS_NTSC_FILM] = ntsc_film_fps;
187  ret = av_expr_parse_and_eval(&res, s->framerate,
188  var_names, var_values,
189  NULL, NULL, NULL, NULL, NULL, 0, ctx);
190  if (ret < 0)
191  return ret;
192 
193  outlink->frame_rate = av_d2q(res, INT_MAX);
194  outlink->time_base = av_inv_q(outlink->frame_rate);
195 
196  /* Calculate the input and output pts offsets for start_time */
197  if (s->start_time != DBL_MAX && s->start_time != AV_NOPTS_VALUE) {
198  double first_pts = s->start_time * AV_TIME_BASE;
199  if (first_pts < INT64_MIN || first_pts > INT64_MAX) {
200  av_log(ctx, AV_LOG_ERROR, "Start time %f cannot be represented in internal time base\n",
201  s->start_time);
202  return AVERROR(EINVAL);
203  }
204  s->in_pts_off = av_rescale_q_rnd(first_pts, AV_TIME_BASE_Q, inlink->time_base,
205  s->rounding | AV_ROUND_PASS_MINMAX);
206  s->out_pts_off = av_rescale_q_rnd(first_pts, AV_TIME_BASE_Q, outlink->time_base,
207  s->rounding | AV_ROUND_PASS_MINMAX);
208  s->next_pts = s->out_pts_off;
209  av_log(ctx, AV_LOG_VERBOSE, "Set first pts to (in:%"PRId64" out:%"PRId64") from start time %f\n",
210  s->in_pts_off, s->out_pts_off, s->start_time);
211  }
212 
213  av_log(ctx, AV_LOG_VERBOSE, "fps=%d/%d\n", outlink->frame_rate.num, outlink->frame_rate.den);
214 
215  return 0;
216 }
217 
218 /* Read a frame from the input and save it in the buffer */
220 {
221  AVFrame *frame;
222  int ret;
223  int64_t in_pts;
224 
225  /* Must only be called when we have buffer room available */
226  av_assert1(s->frames_count < 2);
227 
229  /* Caller must have run ff_inlink_check_available_frame first */
230  av_assert1(ret);
231  if (ret < 0)
232  return ret;
233 
234  /* Convert frame pts to output timebase.
235  * The dance with offsets is required to match the rounding behaviour of the
236  * previous version of the fps filter when using the start_time option. */
237  in_pts = frame->pts;
238  frame->pts = s->out_pts_off + av_rescale_q_rnd(in_pts - s->in_pts_off,
239  inlink->time_base, outlink->time_base,
240  s->rounding | AV_ROUND_PASS_MINMAX);
241 
242  av_log(ctx, AV_LOG_DEBUG, "Read frame with in pts %"PRId64", out pts %"PRId64"\n",
243  in_pts, frame->pts);
244 
245  s->frames[s->frames_count++] = frame;
246  s->frames_in++;
247 
248  return 1;
249 }
250 
251 /* Write a frame to the output */
253 {
254  AVFrame *frame;
255 
256  av_assert1(s->frames_count == 2 || (s->status && s->frames_count == 1));
257 
258  /* We haven't yet determined the pts of the first frame */
259  if (s->next_pts == AV_NOPTS_VALUE) {
260  if (s->frames[0]->pts != AV_NOPTS_VALUE) {
261  s->next_pts = s->frames[0]->pts;
262  av_log(ctx, AV_LOG_VERBOSE, "Set first pts to %"PRId64"\n", s->next_pts);
263  } else {
264  av_log(ctx, AV_LOG_WARNING, "Discarding initial frame(s) with no "
265  "timestamp.\n");
266  frame = shift_frame(ctx, s);
268  *again = 1;
269  return 0;
270  }
271  }
272 
273  /* There are two conditions where we want to drop a frame:
274  * - If we have two buffered frames and the second frame is acceptable
275  * as the next output frame, then drop the first buffered frame.
276  * - If we have status (EOF) set, drop frames when we hit the
277  * status timestamp. */
278  if ((s->frames_count == 2 && s->frames[1]->pts <= s->next_pts) ||
279  (s->status && s->status_pts <= s->next_pts)) {
280 
281  frame = shift_frame(ctx, s);
283  *again = 1;
284  return 0;
285 
286  /* Output a copy of the first buffered frame */
287  } else {
288  frame = av_frame_clone(s->frames[0]);
289  if (!frame)
290  return AVERROR(ENOMEM);
291  // Make sure Closed Captions will not be duplicated
293  frame->pts = s->next_pts++;
294 
295  av_log(ctx, AV_LOG_DEBUG, "Writing frame with pts %"PRId64" to pts %"PRId64"\n",
296  s->frames[0]->pts, frame->pts);
297  s->cur_frame_out++;
298  *again = 1;
299  return ff_filter_frame(outlink, frame);
300  }
301 }
302 
303 /* Convert status_pts to outlink timebase */
304 static void update_eof_pts(AVFilterContext *ctx, FPSContext *s, AVFilterLink *inlink, AVFilterLink *outlink, int64_t status_pts)
305 {
306  int eof_rounding = (s->eof_action == EOF_ACTION_PASS) ? AV_ROUND_UP : s->rounding;
307  s->status_pts = av_rescale_q_rnd(status_pts, inlink->time_base, outlink->time_base,
308  eof_rounding | AV_ROUND_PASS_MINMAX);
309 
310  av_log(ctx, AV_LOG_DEBUG, "EOF is at pts %"PRId64"\n", s->status_pts);
311 }
312 
314 {
315  FPSContext *s = ctx->priv;
316  AVFilterLink *inlink = ctx->inputs[0];
317  AVFilterLink *outlink = ctx->outputs[0];
318 
319  int ret;
320  int again = 0;
321  int64_t status_pts;
322 
324 
325  /* No buffered status: normal operation */
326  if (!s->status) {
327 
328  /* Read available input frames if we have room */
329  while (s->frames_count < 2 && ff_inlink_check_available_frame(inlink)) {
330  ret = read_frame(ctx, s, inlink, outlink);
331  if (ret < 0)
332  return ret;
333  }
334 
335  /* We do not yet have enough frames to produce output */
336  if (s->frames_count < 2) {
337  /* Check if we've hit EOF (or otherwise that an error status is set) */
338  ret = ff_inlink_acknowledge_status(inlink, &s->status, &status_pts);
339  if (ret > 0)
340  update_eof_pts(ctx, s, inlink, outlink, status_pts);
341 
342  if (!ret) {
343  /* If someone wants us to output, we'd better ask for more input */
345  return 0;
346  }
347  }
348  }
349 
350  /* Buffered frames are available, so generate an output frame */
351  if (s->frames_count > 0) {
352  ret = write_frame(ctx, s, outlink, &again);
353  /* Couldn't generate a frame, so schedule us to perform another step */
354  if (again)
355  ff_filter_set_ready(ctx, 100);
356  return ret;
357  }
358 
359  /* No frames left, so forward the status */
360  if (s->status && s->frames_count == 0) {
361  ff_outlink_set_status(outlink, s->status, s->next_pts);
362  return 0;
363  }
364 
365  return FFERROR_NOT_READY;
366 }
367 
369  {
370  .name = "default",
371  .type = AVMEDIA_TYPE_VIDEO,
372  },
373 };
374 
376  {
377  .name = "default",
378  .type = AVMEDIA_TYPE_VIDEO,
379  .config_props = config_props,
380  },
381 };
382 
384  .name = "fps",
385  .description = NULL_IF_CONFIG_SMALL("Force constant framerate."),
386  .init = init,
387  .uninit = uninit,
388  .priv_size = sizeof(FPSContext),
389  .priv_class = &fps_class,
390  .activate = activate,
393 };
AV_LOG_WARNING
#define AV_LOG_WARNING
Something somehow does not look correct.
Definition: log.h:186
AVERROR
Filter the word “frame” indicates either a video frame or a group of audio as stored in an AVFrame structure Format for each input and each output the list of supported formats For video that means pixel format For audio that means channel sample they are references to shared objects When the negotiation mechanism computes the intersection of the formats supported at each end of a all references to both lists are replaced with a reference to the intersection And when a single format is eventually chosen for a link amongst the remaining all references to the list are updated That means that if a filter requires that its input and output have the same format amongst a supported all it has to do is use a reference to the same list of formats query_formats can leave some formats unset and return AVERROR(EAGAIN) to cause the negotiation mechanism toagain later. That can be used by filters with complex requirements to use the format negotiated on one link to set the formats supported on another. Frame references ownership and permissions
opt.h
VARS_NB
@ VARS_NB
Definition: vf_fps.c:61
ff_filter_frame
int ff_filter_frame(AVFilterLink *link, AVFrame *frame)
Send a frame of data to the next filter.
Definition: avfilter.c:1019
FFERROR_NOT_READY
return FFERROR_NOT_READY
Definition: filter_design.txt:204
AV_FRAME_DATA_A53_CC
@ AV_FRAME_DATA_A53_CC
ATSC A53 Part 4 Closed Captions.
Definition: frame.h:58
AV_TIME_BASE_Q
#define AV_TIME_BASE_Q
Internal time base represented as fractional value.
Definition: avutil.h:260
inlink
The exact code depends on how similar the blocks are and how related they are to the and needs to apply these operations to the correct inlink or outlink if there are several Macros are available to factor that when no extra processing is inlink
Definition: filter_design.txt:212
EOF_ACTION_PASS
@ EOF_ACTION_PASS
Definition: vf_fps.c:42
av_frame_free
void av_frame_free(AVFrame **frame)
Free the frame and any dynamically allocated objects in it, e.g.
Definition: frame.c:112
AVFrame
This structure describes decoded (raw) audio or video data.
Definition: frame.h:303
VAR_FPS_NTSC
@ VAR_FPS_NTSC
Definition: vf_fps.c:57
AVOption
AVOption.
Definition: opt.h:247
AV_LOG_VERBOSE
#define AV_LOG_VERBOSE
Detailed information.
Definition: log.h:196
float.h
ntsc_fps
static const double ntsc_fps
Definition: vf_fps.c:64
var_names
static const char *const var_names[]
Definition: vf_fps.c:46
mathematics.h
AVFilter::name
const char * name
Filter name.
Definition: avfilter.h:153
pal_fps
static const double pal_fps
Definition: vf_fps.c:65
init
static av_cold int init(AVFilterContext *ctx)
Definition: vf_fps.c:119
FF_FILTER_FORWARD_STATUS_BACK
#define FF_FILTER_FORWARD_STATUS_BACK(outlink, inlink)
Forward the status on an output link to an input link.
Definition: filters.h:199
config_props
static int config_props(AVFilterLink *outlink)
Definition: vf_fps.c:173
uninit
static av_cold void uninit(AVFilterContext *ctx)
Definition: vf_fps.c:158
framerate
int framerate
Definition: h264_levels.c:65
ff_inlink_consume_frame
int ff_inlink_consume_frame(AVFilterLink *link, AVFrame **rframe)
Take a frame from the link's FIFO and update the link's stats.
Definition: avfilter.c:1418
EOFAction
EOFAction
Definition: framesync.h:26
AV_ROUND_UP
@ AV_ROUND_UP
Round toward +infinity.
Definition: mathematics.h:83
AVRational::num
int num
Numerator.
Definition: rational.h:59
AVFilterPad
A filter pad used for either input or output.
Definition: internal.h:50
avassert.h
AV_LOG_ERROR
#define AV_LOG_ERROR
Something went wrong and cannot losslessly be recovered.
Definition: log.h:180
update_eof_pts
static void update_eof_pts(AVFilterContext *ctx, FPSContext *s, AVFilterLink *inlink, AVFilterLink *outlink, int64_t status_pts)
Definition: vf_fps.c:304
av_cold
#define av_cold
Definition: attributes.h:90
ff_outlink_set_status
static void ff_outlink_set_status(AVFilterLink *link, int status, int64_t pts)
Set the status field of a link from the source filter.
Definition: filters.h:189
FPSContext::eof_action
int eof_action
action performed for last frame in FIFO
Definition: vf_fps.c:76
s
#define s(width, name)
Definition: cbs_vp9.c:257
FPSContext::frames_in
int frames_in
number of frames on input
Definition: vf_fps.c:93
AV_OPT_TYPE_DOUBLE
@ AV_OPT_TYPE_DOUBLE
Definition: opt.h:226
V
#define V
Definition: vf_fps.c:100
av_q2d
static double av_q2d(AVRational a)
Convert an AVRational to a double.
Definition: rational.h:104
filters.h
var_name
var_name
Definition: noise_bsf.c:47
AV_LOG_DEBUG
#define AV_LOG_DEBUG
Stuff which is only useful for libav* developers.
Definition: log.h:201
ctx
AVFormatContext * ctx
Definition: movenc.c:48
av_frame_clone
AVFrame * av_frame_clone(const AVFrame *src)
Create a new frame that references the same data as src.
Definition: frame.c:424
FPSContext::frames_count
int frames_count
number of buffered frames
Definition: vf_fps.c:87
FILTER_INPUTS
#define FILTER_INPUTS(array)
Definition: internal.h:152
write_frame
static int write_frame(AVFilterContext *ctx, FPSContext *s, AVFilterLink *outlink, int *again)
Definition: vf_fps.c:252
FPSContext::out_pts_off
int64_t out_pts_off
output frame pts offset for start_time handling
Definition: vf_fps.c:80
ntsc_film_fps
static const double ntsc_film_fps
Definition: vf_fps.c:67
OFFSET
#define OFFSET(x)
Definition: vf_fps.c:99
AVClass
Describe the class of an AVClass context structure.
Definition: log.h:66
NULL
#define NULL
Definition: coverity.c:32
AV_ROUND_INF
@ AV_ROUND_INF
Round away from zero.
Definition: mathematics.h:81
avfilter_vf_fps_outputs
static const AVFilterPad avfilter_vf_fps_outputs[]
Definition: vf_fps.c:375
AV_ROUND_NEAR_INF
@ AV_ROUND_NEAR_INF
Round to nearest and halfway cases away from zero.
Definition: mathematics.h:84
FPSContext::status_pts
int64_t status_pts
buffered input status timestamp
Definition: vf_fps.c:84
FPSContext::frames
AVFrame * frames[2]
buffered frames
Definition: vf_fps.c:86
ff_inlink_acknowledge_status
int ff_inlink_acknowledge_status(AVFilterLink *link, int *rstatus, int64_t *rpts)
Test and acknowledge the change of status on the link.
Definition: avfilter.c:1372
VAR_FPS_FILM
@ VAR_FPS_FILM
Definition: vf_fps.c:59
FPSContext::status
int status
buffered input status
Definition: vf_fps.c:83
avfilter_vf_fps_inputs
static const AVFilterPad avfilter_vf_fps_inputs[]
Definition: vf_fps.c:368
read_frame
static int read_frame(AVFilterContext *ctx, FPSContext *s, AVFilterLink *inlink, AVFilterLink *outlink)
Definition: vf_fps.c:219
eval.h
FPSContext
Definition: vf_fps.c:69
ff_inlink_check_available_frame
int ff_inlink_check_available_frame(AVFilterLink *link)
Test if a frame is available on the link.
Definition: avfilter.c:1392
NULL_IF_CONFIG_SMALL
#define NULL_IF_CONFIG_SMALL(x)
Return NULL if CONFIG_SMALL is true, otherwise the argument without modification.
Definition: internal.h:117
av_expr_parse_and_eval
int av_expr_parse_and_eval(double *d, const char *s, const char *const *const_names, const double *const_values, const char *const *func1_names, double(*const *funcs1)(void *, double), const char *const *func2_names, double(*const *funcs2)(void *, double, double), void *opaque, int log_offset, void *log_ctx)
Parse and evaluate an expression.
Definition: eval.c:776
AV_ROUND_ZERO
@ AV_ROUND_ZERO
Round toward zero.
Definition: mathematics.h:80
start_time
static int64_t start_time
Definition: ffplay.c:330
AV_NOPTS_VALUE
#define AV_NOPTS_VALUE
Undefined timestamp value.
Definition: avutil.h:248
ff_vf_fps
const AVFilter ff_vf_fps
Definition: vf_fps.c:383
EOF_ACTION_ROUND
@ EOF_ACTION_ROUND
Definition: vf_fps.c:41
av_frame_remove_side_data
void av_frame_remove_side_data(AVFrame *frame, enum AVFrameSideDataType type)
Remove and free all side data instances of the given type.
Definition: frame.c:691
FPSContext::next_pts
int64_t next_pts
pts of the next frame to output
Definition: vf_fps.c:89
FF_FILTER_FORWARD_WANTED
FF_FILTER_FORWARD_WANTED(outlink, inlink)
EOF_ACTION_NB
@ EOF_ACTION_NB
Definition: vf_fps.c:43
FPSContext::drop
int drop
number of framed dropped
Definition: vf_fps.c:96
internal.h
shift_frame
static AVFrame * shift_frame(AVFilterContext *ctx, FPSContext *s)
Definition: vf_fps.c:130
FPSContext::framerate
char * framerate
expression that defines the target framerate
Definition: vf_fps.c:74
AV_TIME_BASE
#define AV_TIME_BASE
Internal time base represented as integer.
Definition: avutil.h:254
av_assert1
#define av_assert1(cond)
assert() equivalent, that does not lie in speed critical code.
Definition: avassert.h:53
AV_ROUND_DOWN
@ AV_ROUND_DOWN
Round toward -infinity.
Definition: mathematics.h:82
av_d2q
AVRational av_d2q(double d, int max)
Convert a double precision floating point number to a rational.
Definition: rational.c:106
av_inv_q
static av_always_inline AVRational av_inv_q(AVRational q)
Invert a rational.
Definition: rational.h:159
AVFilterPad::name
const char * name
Pad name.
Definition: internal.h:56
AVFilter
Filter definition.
Definition: avfilter.h:149
ret
ret
Definition: filter_design.txt:187
frame
these buffered frames must be flushed immediately if a new input produces new the filter must not call request_frame to get more It must just process the frame or queue it The task of requesting more frames is left to the filter s request_frame method or the application If a filter has several the filter must be ready for frames arriving randomly on any input any filter with several inputs will most likely require some kind of queuing mechanism It is perfectly acceptable to have a limited queue and to drop frames when the inputs are too unbalanced request_frame For filters that do not use the this method is called when a frame is wanted on an output For a it should directly call filter_frame on the corresponding output For a if there are queued frames already one of these frames should be pushed If the filter should request a frame on one of its repeatedly until at least one frame has been pushed Return or at least make progress towards producing a frame
Definition: filter_design.txt:264
again
Filter the word “frame” indicates either a video frame or a group of audio as stored in an AVFrame structure Format for each input and each output the list of supported formats For video that means pixel format For audio that means channel sample they are references to shared objects When the negotiation mechanism computes the intersection of the formats supported at each end of a all references to both lists are replaced with a reference to the intersection And when a single format is eventually chosen for a link amongst the remaining again
Definition: filter_design.txt:25
AVRational::den
int den
Denominator.
Definition: rational.h:60
AV_OPT_TYPE_INT
@ AV_OPT_TYPE_INT
Definition: opt.h:224
avfilter.h
FPSContext::in_pts_off
int64_t in_pts_off
input frame pts offset for start_time handling
Definition: vf_fps.c:79
film_fps
static const double film_fps
Definition: vf_fps.c:66
F
#define F
Definition: vf_fps.c:101
FPSContext::dup
int dup
number of frames duplicated
Definition: vf_fps.c:95
AVFilterContext
An instance of a filter.
Definition: avfilter.h:346
AVMEDIA_TYPE_VIDEO
@ AVMEDIA_TYPE_VIDEO
Definition: avutil.h:201
FPSContext::start_time
double start_time
pts, in seconds, of the expected first frame
Definition: vf_fps.c:72
AV_ROUND_PASS_MINMAX
@ AV_ROUND_PASS_MINMAX
Flag telling rescaling functions to pass INT64_MIN/MAX through unchanged, avoiding special cases for ...
Definition: mathematics.h:108
AVFILTER_DEFINE_CLASS
AVFILTER_DEFINE_CLASS(fps)
activate
static int activate(AVFilterContext *ctx)
Definition: vf_fps.c:313
FILTER_OUTPUTS
#define FILTER_OUTPUTS(array)
Definition: internal.h:153
fps_options
static const AVOption fps_options[]
Definition: vf_fps.c:102
av_log
#define av_log(a,...)
Definition: tableprint_vlc.h:28
FPSContext::cur_frame_out
int cur_frame_out
number of times current frame has been output
Definition: vf_fps.c:92
VAR_FPS_NTSC_FILM
@ VAR_FPS_NTSC_FILM
Definition: vf_fps.c:60
AV_OPT_TYPE_STRING
@ AV_OPT_TYPE_STRING
Definition: opt.h:228
VAR_SOURCE_FPS
@ VAR_SOURCE_FPS
Definition: vf_fps.c:56
AV_OPT_TYPE_CONST
@ AV_OPT_TYPE_CONST
Definition: opt.h:233
av_rescale_q_rnd
int64_t av_rescale_q_rnd(int64_t a, AVRational bq, AVRational cq, enum AVRounding rnd)
Rescale a 64-bit integer by 2 rational numbers with specified rounding.
Definition: mathematics.c:133
FPSContext::frames_out
int frames_out
number of frames on output
Definition: vf_fps.c:94
FPSContext::rounding
int rounding
AVRounding method for timestamps.
Definition: vf_fps.c:75
ff_filter_set_ready
void ff_filter_set_ready(AVFilterContext *filter, unsigned priority)
Mark a filter ready and schedule it for activation.
Definition: avfilter.c:212
VAR_FPS_PAL
@ VAR_FPS_PAL
Definition: vf_fps.c:58