FFmpeg
f_realtime.c
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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 */
av_gettime_relative
int64_t av_gettime_relative(void)
Get the current time in microseconds since some unspecified starting point.
Definition: time.c:56
AV_LOG_WARNING
#define AV_LOG_WARNING
Something somehow does not look correct.
Definition: log.h:200
RealtimeContext::speed
double speed
Definition: f_realtime.c:31
opt.h
ff_filter_frame
int ff_filter_frame(AVFilterLink *link, AVFrame *frame)
Send a frame of data to the next filter.
Definition: avfilter.c:1094
RealtimeContext::limit
int64_t limit
Definition: f_realtime.c:30
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
AVFrame
This structure describes decoded (raw) audio or video data.
Definition: frame.h:324
AVOption
AVOption.
Definition: opt.h:248
AV_OPT_TYPE_DURATION
@ AV_OPT_TYPE_DURATION
Definition: opt.h:239
float.h
AVFilter::name
const char * name
Filter name.
Definition: avfilter.h:149
options
static const AVOption options[]
Definition: f_realtime.c:68
RealtimeContext::delta
int64_t delta
Definition: f_realtime.c:29
pts
static int64_t pts
Definition: transcode_aac.c:652
AVFilterPad
A filter pad used for either input or output.
Definition: internal.h:54
inputs
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
Definition: filter_design.txt:243
s
#define s(width, name)
Definition: cbs_vp9.c:257
AV_OPT_TYPE_DOUBLE
@ AV_OPT_TYPE_DOUBLE
Definition: opt.h:227
AVMEDIA_TYPE_AUDIO
@ AVMEDIA_TYPE_AUDIO
Definition: avutil.h:202
ff_af_arealtime
AVFilter ff_af_arealtime
outputs
static const AVFilterPad outputs[]
Definition: af_acontrast.c:203
AV_LOG_DEBUG
#define AV_LOG_DEBUG
Stuff which is only useful for libav* developers.
Definition: log.h:215
ctx
AVFormatContext * ctx
Definition: movenc.c:48
av_rescale_q
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
RealtimeContext::inited
unsigned inited
Definition: f_realtime.c:32
av_usleep
int av_usleep(unsigned usec)
Sleep for a period of time.
Definition: time.c:84
FFABS
#define FFABS(a)
Absolute value, Note, INT_MIN / INT64_MIN result in undefined behavior as they are not representable ...
Definition: common.h:72
RealtimeContext
Definition: f_realtime.c:27
AVClass
Describe the class of an AVClass context structure.
Definition: log.h:67
NULL
#define NULL
Definition: coverity.c:32
time.h
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_NOPTS_VALUE
#define AV_NOPTS_VALUE
Undefined timestamp value.
Definition: avutil.h:248
filter_frame
static int filter_frame(AVFilterLink *inlink, AVFrame *frame)
Definition: f_realtime.c:35
internal.h
AVFILTER_DEFINE_CLASS
#define AVFILTER_DEFINE_CLASS(fname)
Definition: internal.h:288
FLAGS
#define FLAGS
Definition: f_realtime.c:67
AVFilterPad::name
const char * name
Pad name.
Definition: internal.h:60
OFFSET
#define OFFSET(x)
Definition: f_realtime.c:66
AVFilter
Filter definition.
Definition: avfilter.h:145
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
avfilter.h
AVFilterContext
An instance of a filter.
Definition: avfilter.h:341
AVMEDIA_TYPE_VIDEO
@ AVMEDIA_TYPE_VIDEO
Definition: avutil.h:201
av_log
#define av_log(a,...)
Definition: tableprint_vlc.h:28
ff_vf_realtime
AVFilter ff_vf_realtime