FFmpeg
 All Data Structures Namespaces Files Functions Variables Typedefs Enumerations Enumerator Macros Groups Pages
vf_random.c
Go to the documentation of this file.
1 /*
2  * Copyright (c) 2015 Paul B Mahol
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
8  * License 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 GNU
14  * Lesser General Public License for more details.
15  *
16  * You should have received a copy of the GNU Lesser General Public
17  * License along with FFmpeg; if not, write to the Free Software
18  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
19  */
20 
21 #include "libavutil/lfg.h"
22 #include "libavutil/opt.h"
23 #include "libavutil/random_seed.h"
24 #include "avfilter.h"
25 #include "formats.h"
26 #include "internal.h"
27 #include "video.h"
28 
29 #define MAX_FRAMES 512
30 
31 typedef struct RandomContext {
32  const AVClass *class;
33 
35  int nb_frames;
36  int64_t random_seed;
39  int64_t pts[MAX_FRAMES];
40  int flush_idx;
42 
43 #define OFFSET(x) offsetof(RandomContext, x)
44 #define FLAGS AV_OPT_FLAG_VIDEO_PARAM|AV_OPT_FLAG_FILTERING_PARAM
45 
46 static const AVOption random_options[] = {
47  { "frames", "set number of frames in cache", OFFSET(nb_frames), AV_OPT_TYPE_INT, {.i64=30}, 2, MAX_FRAMES, FLAGS },
48  { "seed", "set the seed", OFFSET(random_seed), AV_OPT_TYPE_INT64, {.i64=-1}, -1, UINT32_MAX, FLAGS },
49  { NULL }
50 };
51 
52 AVFILTER_DEFINE_CLASS(random);
53 
55 {
56  RandomContext *s = ctx->priv;
57  uint32_t seed;
58 
59  if (s->random_seed < 0)
61  seed = s->random_seed;
62  av_lfg_init(&s->lfg, seed);
63 
64  return 0;
65 }
66 
67 static int filter_frame(AVFilterLink *inlink, AVFrame *in)
68 {
69  AVFilterContext *ctx = inlink->dst;
70  RandomContext *s = ctx->priv;
71  AVFilterLink *outlink = ctx->outputs[0];
72  AVFrame *out;
73  int idx;
74 
75  if (s->nb_frames_filled < s->nb_frames) {
76  s->frames[s->nb_frames_filled] = in;
77  s->pts[s->nb_frames_filled++] = in->pts;
78  return 0;
79  }
80 
81  idx = av_lfg_get(&s->lfg) % s->nb_frames;
82 
83  out = s->frames[idx];
84  out->pts = s->pts[0];
85  memmove(&s->pts[0], &s->pts[1], (s->nb_frames - 1) * sizeof(s->pts[0]));
86  s->frames[idx] = in;
87  s->pts[s->nb_frames - 1] = in->pts;
88 
89  return ff_filter_frame(outlink, out);
90 }
91 
92 static int request_frame(AVFilterLink *outlink)
93 {
94  AVFilterContext *ctx = outlink->src;
95  RandomContext *s = ctx->priv;
96  int ret;
97 
98  ret = ff_request_frame(ctx->inputs[0]);
99 
100  if (ret == AVERROR_EOF && !ctx->is_disabled && s->nb_frames > 0) {
101  AVFrame *out = s->frames[s->nb_frames - 1];
102  out->pts = s->pts[s->flush_idx++];
103  ret = ff_filter_frame(outlink, out);
104  s->frames[s->nb_frames - 1] = NULL;
105  s->nb_frames--;
106  }
107 
108  return ret;
109 }
110 
111 static const AVFilterPad random_inputs[] = {
112  {
113  .name = "default",
114  .type = AVMEDIA_TYPE_VIDEO,
115  .filter_frame = filter_frame,
116  },
117  { NULL }
118 };
119 
120 static const AVFilterPad random_outputs[] = {
121  {
122  .name = "default",
123  .type = AVMEDIA_TYPE_VIDEO,
124  .request_frame = request_frame,
125  },
126  { NULL }
127 };
128 
130  .name = "random",
131  .description = NULL_IF_CONFIG_SMALL("Return random frames."),
132  .priv_size = sizeof(RandomContext),
133  .priv_class = &random_class,
134  .init = init,
135  .inputs = random_inputs,
136  .outputs = random_outputs,
137 };
Definition: lfg.h:27
#define NULL
Definition: coverity.c:32
const char * s
Definition: avisynth_c.h:768
This structure describes decoded (raw) audio or video data.
Definition: frame.h:187
int64_t random_seed
Definition: vf_random.c:36
AVOption.
Definition: opt.h:246
Main libavfilter public API header.
static const AVOption random_options[]
Definition: vf_random.c:46
AVFrame * frames[MAX_FRAMES]
Definition: vf_random.c:38
#define OFFSET(x)
Definition: vf_random.c:43
int64_t pts[MAX_FRAMES]
Definition: vf_random.c:39
int is_disabled
the enabled state from the last expression evaluation
Definition: avfilter.h:370
const char * name
Pad name.
Definition: internal.h:60
AVFilterLink ** inputs
array of pointers to input links
Definition: avfilter.h:331
int ff_filter_frame(AVFilterLink *link, AVFrame *frame)
Send a frame of data to the next filter.
Definition: avfilter.c:1125
#define av_cold
Definition: attributes.h:82
AVOptions.
int64_t pts
Presentation timestamp in time_base units (time when frame should be shown to user).
Definition: frame.h:271
#define AVERROR_EOF
End of file.
Definition: error.h:55
A filter pad used for either input or output.
Definition: internal.h:54
AVFILTER_DEFINE_CLASS(random)
static int request_frame(AVFilterLink *outlink)
Definition: vf_random.c:92
#define NULL_IF_CONFIG_SMALL(x)
Return NULL if CONFIG_SMALL is true, otherwise the argument without modification. ...
Definition: internal.h:179
void * priv
private data for use by the filter
Definition: avfilter.h:338
#define FLAGS
Definition: vf_random.c:44
AVFilter ff_vf_random
Definition: vf_random.c:129
AVFormatContext * ctx
Definition: movenc.c:48
static const AVFilterPad outputs[]
Definition: af_afftfilt.c:386
int nb_frames_filled
Definition: vf_random.c:37
static int filter_frame(AVFilterLink *inlink, AVFrame *in)
Definition: vf_random.c:67
static const AVFilterPad inputs[]
Definition: af_afftfilt.c:376
static unsigned int seed
Definition: videogen.c:78
uint8_t pi<< 24) CONV_FUNC_GROUP(AV_SAMPLE_FMT_FLT, float, AV_SAMPLE_FMT_U8, uint8_t,(*(constuint8_t *) pi-0x80)*(1.0f/(1<< 7))) CONV_FUNC_GROUP(AV_SAMPLE_FMT_DBL, double, AV_SAMPLE_FMT_U8, uint8_t,(*(constuint8_t *) pi-0x80)*(1.0/(1<< 7))) CONV_FUNC_GROUP(AV_SAMPLE_FMT_U8, uint8_t, AV_SAMPLE_FMT_S16, int16_t,(*(constint16_t *) pi >>8)+0x80) CONV_FUNC_GROUP(AV_SAMPLE_FMT_FLT, float, AV_SAMPLE_FMT_S16, int16_t,*(constint16_t *) pi *(1.0f/(1<< 15))) CONV_FUNC_GROUP(AV_SAMPLE_FMT_DBL, double, AV_SAMPLE_FMT_S16, int16_t,*(constint16_t *) pi *(1.0/(1<< 15))) CONV_FUNC_GROUP(AV_SAMPLE_FMT_U8, uint8_t, AV_SAMPLE_FMT_S32, int32_t,(*(constint32_t *) pi >>24)+0x80) CONV_FUNC_GROUP(AV_SAMPLE_FMT_FLT, float, AV_SAMPLE_FMT_S32, int32_t,*(constint32_t *) pi *(1.0f/(1U<< 31))) CONV_FUNC_GROUP(AV_SAMPLE_FMT_DBL, double, AV_SAMPLE_FMT_S32, int32_t,*(constint32_t *) pi *(1.0/(1U<< 31))) CONV_FUNC_GROUP(AV_SAMPLE_FMT_U8, uint8_t, AV_SAMPLE_FMT_FLT, float, av_clip_uint8(lrintf(*(constfloat *) pi *(1<< 7))+0x80)) CONV_FUNC_GROUP(AV_SAMPLE_FMT_S16, int16_t, AV_SAMPLE_FMT_FLT, float, av_clip_int16(lrintf(*(constfloat *) pi *(1<< 15)))) CONV_FUNC_GROUP(AV_SAMPLE_FMT_S32, int32_t, AV_SAMPLE_FMT_FLT, float, av_clipl_int32(llrintf(*(constfloat *) pi *(1U<< 31)))) CONV_FUNC_GROUP(AV_SAMPLE_FMT_U8, uint8_t, AV_SAMPLE_FMT_DBL, double, av_clip_uint8(lrint(*(constdouble *) pi *(1<< 7))+0x80)) CONV_FUNC_GROUP(AV_SAMPLE_FMT_S16, int16_t, AV_SAMPLE_FMT_DBL, double, av_clip_int16(lrint(*(constdouble *) pi *(1<< 15)))) CONV_FUNC_GROUP(AV_SAMPLE_FMT_S32, int32_t, AV_SAMPLE_FMT_DBL, double, av_clipl_int32(llrint(*(constdouble *) pi *(1U<< 31))))#defineSET_CONV_FUNC_GROUP(ofmt, ifmt) staticvoidset_generic_function(AudioConvert *ac){}voidff_audio_convert_free(AudioConvert **ac){if(!*ac) return;ff_dither_free(&(*ac) ->dc);av_freep(ac);}AudioConvert *ff_audio_convert_alloc(AVAudioResampleContext *avr, enumAVSampleFormatout_fmt, enumAVSampleFormatin_fmt, intchannels, intsample_rate, intapply_map){AudioConvert *ac;intin_planar, out_planar;ac=av_mallocz(sizeof(*ac));if(!ac) returnNULL;ac->avr=avr;ac->out_fmt=out_fmt;ac->in_fmt=in_fmt;ac->channels=channels;ac->apply_map=apply_map;if(avr->dither_method!=AV_RESAMPLE_DITHER_NONE &&av_get_packed_sample_fmt(out_fmt)==AV_SAMPLE_FMT_S16 &&av_get_bytes_per_sample(in_fmt)>2){ac->dc=ff_dither_alloc(avr, out_fmt, in_fmt, channels, sample_rate, apply_map);if(!ac->dc){av_free(ac);returnNULL;}returnac;}in_planar=ff_sample_fmt_is_planar(in_fmt, channels);out_planar=ff_sample_fmt_is_planar(out_fmt, channels);if(in_planar==out_planar){ac->func_type=CONV_FUNC_TYPE_FLAT;ac->planes=in_planar?ac->channels:1;}elseif(in_planar) ac->func_type=CONV_FUNC_TYPE_INTERLEAVE;elseac->func_type=CONV_FUNC_TYPE_DEINTERLEAVE;set_generic_function(ac);if(ARCH_AARCH64) ff_audio_convert_init_aarch64(ac);if(ARCH_ARM) ff_audio_convert_init_arm(ac);if(ARCH_X86) ff_audio_convert_init_x86(ac);returnac;}intff_audio_convert(AudioConvert *ac, AudioData *out, AudioData *in){intuse_generic=1;intlen=in->nb_samples;intp;if(ac->dc){av_log(ac->avr, AV_LOG_TRACE,"%dsamples-audio_convert:%sto%s(dithered)\n", len, av_get_sample_fmt_name(ac->in_fmt), av_get_sample_fmt_name(ac->out_fmt));returnff_convert_dither(ac-> in
static unsigned int av_lfg_get(AVLFG *c)
Get the next random unsigned 32-bit number using an ALFG.
Definition: lfg.h:47
#define MAX_FRAMES
Definition: vf_random.c:29
Describe the class of an AVClass context structure.
Definition: log.h:67
Filter definition.
Definition: avfilter.h:144
static av_cold int init(AVFilterContext *ctx)
Definition: vf_random.c:54
const char * name
Filter name.
Definition: avfilter.h:148
av_cold void av_lfg_init(AVLFG *c, unsigned int seed)
Definition: lfg.c:32
AVFilterLink ** outputs
array of pointers to output links
Definition: avfilter.h:335
An instance of a filter.
Definition: avfilter.h:323
FILE * out
Definition: movenc.c:54
uint32_t av_get_random_seed(void)
Get a seed to use in conjunction with random functions.
Definition: random_seed.c:120
int ff_request_frame(AVFilterLink *link)
Request an input frame from the filter at the other end of the link.
Definition: avfilter.c:405
internal API functions
static const AVFilterPad random_outputs[]
Definition: vf_random.c:120
static const AVFilterPad random_inputs[]
Definition: vf_random.c:111