FFmpeg
f_realtime.c
Go to the documentation of this file.
1 /*
2  * Copyright (c) 2015 Nicolas George
3  *
4  * This file is part of FFmpeg.
5  *
6  * FFmpeg is free software; you can redistribute it and/or
7  * modify it under the terms of the GNU Lesser General Public License
8  * as published by the Free Software Foundation; either
9  * version 2.1 of the License, or (at your option) any later version.
10  *
11  * FFmpeg is distributed in the hope that it will be useful,
12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14  * GNU Lesser General Public License for more details.
15  *
16  * You should have received a copy of the GNU Lesser General Public License
17  * along with FFmpeg; if not, write to the Free Software Foundation, Inc.,
18  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
19  */
20 
21 #include "libavutil/opt.h"
22 #include "libavutil/time.h"
23 #include "avfilter.h"
24 #include "internal.h"
25 #include <float.h>
26 
27 typedef struct RealtimeContext {
28  const AVClass *class;
29  int64_t delta;
30  int64_t limit;
31  double speed;
32  unsigned inited;
34 
36 {
37  AVFilterContext *ctx = inlink->dst;
38  RealtimeContext *s = ctx->priv;
39 
40  if (frame->pts != AV_NOPTS_VALUE) {
41  int64_t pts = av_rescale_q(frame->pts, inlink->time_base, AV_TIME_BASE_Q) / s->speed;
42  int64_t now = av_gettime_relative();
43  int64_t sleep = pts - now + s->delta;
44  if (!s->inited) {
45  s->inited = 1;
46  sleep = 0;
47  s->delta = now - pts;
48  }
49  if (FFABS(sleep) > s->limit / s->speed) {
51  "time discontinuity detected: %"PRIi64" us, resetting\n",
52  sleep);
53  sleep = 0;
54  s->delta = now - pts;
55  }
56  if (sleep > 0) {
57  av_log(ctx, AV_LOG_DEBUG, "sleeping %"PRIi64" us\n", sleep);
58  for (; sleep > 600000000; sleep -= 600000000)
59  av_usleep(600000000);
60  av_usleep(sleep);
61  }
62  }
63  return ff_filter_frame(inlink->dst->outputs[0], frame);
64 }
65 
66 #define OFFSET(x) offsetof(RealtimeContext, x)
67 #define FLAGS AV_OPT_FLAG_VIDEO_PARAM | AV_OPT_FLAG_AUDIO_PARAM | AV_OPT_FLAG_FILTERING_PARAM
68 static const AVOption options[] = {
69  { "limit", "sleep time limit", OFFSET(limit), AV_OPT_TYPE_DURATION, { .i64 = 2000000 }, 0, INT64_MAX, FLAGS },
70  { "speed", "speed factor", OFFSET(speed), AV_OPT_TYPE_DOUBLE, { .dbl = 1.0 }, DBL_MIN, DBL_MAX, FLAGS },
71  { NULL }
72 };
73 
74 #if CONFIG_REALTIME_FILTER
75 #define realtime_options options
76 AVFILTER_DEFINE_CLASS(realtime);
77 
78 static const AVFilterPad avfilter_vf_realtime_inputs[] = {
79  {
80  .name = "default",
81  .type = AVMEDIA_TYPE_VIDEO,
82  .filter_frame = filter_frame,
83  },
84  { NULL }
85 };
86 
87 static const AVFilterPad avfilter_vf_realtime_outputs[] = {
88  {
89  .name = "default",
90  .type = AVMEDIA_TYPE_VIDEO,
91  },
92  { NULL }
93 };
94 
96  .name = "realtime",
97  .description = NULL_IF_CONFIG_SMALL("Slow down filtering to match realtime."),
98  .priv_size = sizeof(RealtimeContext),
99  .priv_class = &realtime_class,
100  .inputs = avfilter_vf_realtime_inputs,
101  .outputs = avfilter_vf_realtime_outputs,
102 };
103 #endif /* CONFIG_REALTIME_FILTER */
104 
105 #if CONFIG_AREALTIME_FILTER
106 
107 #define arealtime_options options
108 AVFILTER_DEFINE_CLASS(arealtime);
109 
110 static const AVFilterPad arealtime_inputs[] = {
111  {
112  .name = "default",
113  .type = AVMEDIA_TYPE_AUDIO,
114  .filter_frame = filter_frame,
115  },
116  { NULL }
117 };
118 
119 static const AVFilterPad arealtime_outputs[] = {
120  {
121  .name = "default",
122  .type = AVMEDIA_TYPE_AUDIO,
123  },
124  { NULL }
125 };
126 
128  .name = "arealtime",
129  .description = NULL_IF_CONFIG_SMALL("Slow down filtering to match realtime."),
130  .priv_size = sizeof(RealtimeContext),
131  .priv_class = &arealtime_class,
132  .inputs = arealtime_inputs,
133  .outputs = arealtime_outputs,
134 };
135 #endif /* CONFIG_AREALTIME_FILTER */
#define NULL
Definition: coverity.c:32
This structure describes decoded (raw) audio or video data.
Definition: frame.h:295
AVOption.
Definition: opt.h:246
#define AV_LOG_WARNING
Something somehow does not look correct.
Definition: log.h:182
Main libavfilter public API header.
#define OFFSET(x)
Definition: f_realtime.c:66
int av_usleep(unsigned usec)
Sleep for a period of time.
Definition: time.c:84
const char * name
Pad name.
Definition: internal.h:60
int ff_filter_frame(AVFilterLink *link, AVFrame *frame)
Send a frame of data to the next filter.
Definition: avfilter.c:1080
static int filter_frame(AVFilterLink *inlink, AVFrame *frame)
Definition: f_realtime.c:35
AVOptions.
int64_t pts
Presentation timestamp in time_base units (time when frame should be shown to user).
Definition: frame.h:388
#define av_log(a,...)
A filter pad used for either input or output.
Definition: internal.h:54
int64_t av_rescale_q(int64_t a, AVRational bq, AVRational cq)
Rescale a 64-bit integer by 2 rational numbers.
Definition: mathematics.c:142
#define FLAGS
Definition: f_realtime.c:67
#define NULL_IF_CONFIG_SMALL(x)
Return NULL if CONFIG_SMALL is true, otherwise the argument without modification. ...
Definition: internal.h:186
void * priv
private data for use by the filter
Definition: avfilter.h:353
#define AV_LOG_DEBUG
Stuff which is only useful for libav* developers.
Definition: log.h:197
AVFilter ff_vf_realtime
AVFilter ff_af_arealtime
AVFormatContext * ctx
Definition: movenc.c:48
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
#define FFABS(a)
Absolute value, Note, INT_MIN / INT64_MIN result in undefined behavior as they are not representable ...
Definition: common.h:72
#define s(width, name)
Definition: cbs_vp9.c:257
static const AVFilterPad outputs[]
Definition: af_acontrast.c:203
#define AV_TIME_BASE_Q
Internal time base represented as fractional value.
Definition: avutil.h:260
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 inputs
Describe the class of an AVClass context structure.
Definition: log.h:67
Filter definition.
Definition: avfilter.h:144
int64_t limit
Definition: f_realtime.c:30
const char * name
Filter name.
Definition: avfilter.h:148
unsigned inited
Definition: f_realtime.c:32
AVFilterLink ** outputs
array of pointers to output links
Definition: avfilter.h:350
static int64_t pts
int64_t av_gettime_relative(void)
Get the current time in microseconds since some unspecified starting point.
Definition: time.c:56
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
static const AVOption options[]
Definition: f_realtime.c:68
#define AVFILTER_DEFINE_CLASS(fname)
Definition: internal.h:334
An instance of a filter.
Definition: avfilter.h:338
int64_t delta
Definition: f_realtime.c:29
internal API functions
#define AV_NOPTS_VALUE
Undefined timestamp value.
Definition: avutil.h:248