FFmpeg
af_drmeter.c
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1 /*
2  * Copyright (c) 2018 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 <float.h>
22 
23 #include "libavutil/ffmath.h"
24 #include "libavutil/opt.h"
25 #include "audio.h"
26 #include "avfilter.h"
27 #include "internal.h"
28 
29 typedef struct ChannelStats {
30  uint64_t nb_samples;
31  uint64_t blknum;
32  float peak;
33  float sum;
34  uint32_t peaks[10001];
35  uint32_t rms[10001];
36 } ChannelStats;
37 
38 typedef struct DRMeterContext {
39  const AVClass *class;
42  uint64_t tc_samples;
43  double time_constant;
45 
46 #define OFFSET(x) offsetof(DRMeterContext, x)
47 #define FLAGS AV_OPT_FLAG_AUDIO_PARAM|AV_OPT_FLAG_FILTERING_PARAM
48 
49 static const AVOption drmeter_options[] = {
50  { "length", "set the window length", OFFSET(time_constant), AV_OPT_TYPE_DOUBLE, {.dbl=3}, .01, 10, FLAGS },
51  { NULL }
52 };
53 
54 AVFILTER_DEFINE_CLASS(drmeter);
55 
57 {
60  static const enum AVSampleFormat sample_fmts[] = {
63  };
64  int ret;
65 
66  layouts = ff_all_channel_counts();
67  if (!layouts)
68  return AVERROR(ENOMEM);
69  ret = ff_set_common_channel_layouts(ctx, layouts);
70  if (ret < 0)
71  return ret;
72 
73  formats = ff_make_format_list(sample_fmts);
74  if (!formats)
75  return AVERROR(ENOMEM);
76  ret = ff_set_common_formats(ctx, formats);
77  if (ret < 0)
78  return ret;
79 
80  formats = ff_all_samplerates();
81  if (!formats)
82  return AVERROR(ENOMEM);
83  return ff_set_common_samplerates(ctx, formats);
84 }
85 
86 static int config_output(AVFilterLink *outlink)
87 {
88  DRMeterContext *s = outlink->src->priv;
89 
90  s->chstats = av_calloc(sizeof(*s->chstats), outlink->channels);
91  if (!s->chstats)
92  return AVERROR(ENOMEM);
93  s->nb_channels = outlink->channels;
94  s->tc_samples = s->time_constant * outlink->sample_rate + .5;
95 
96  return 0;
97 }
98 
99 static void finish_block(ChannelStats *p)
100 {
101  int peak_bin, rms_bin;
102  float peak, rms;
103 
104  rms = sqrt(2 * p->sum / p->nb_samples);
105  peak = p->peak;
106  rms_bin = av_clip(rms * 10000, 0, 10000);
107  peak_bin = av_clip(peak * 10000, 0, 10000);
108  p->rms[rms_bin]++;
109  p->peaks[peak_bin]++;
110 
111  p->peak = 0;
112  p->sum = 0;
113  p->nb_samples = 0;
114  p->blknum++;
115 }
116 
118 {
119  if (p->nb_samples >= s->tc_samples) {
120  finish_block(p);
121  }
122 
123  p->peak = FFMAX(FFABS(sample), p->peak);
124  p->sum += sample * sample;
125  p->nb_samples++;
126 }
127 
129 {
130  DRMeterContext *s = inlink->dst->priv;
131  const int channels = s->nb_channels;
132  int i, c;
133 
134  switch (inlink->format) {
135  case AV_SAMPLE_FMT_FLTP:
136  for (c = 0; c < channels; c++) {
137  ChannelStats *p = &s->chstats[c];
138  const float *src = (const float *)buf->extended_data[c];
139 
140  for (i = 0; i < buf->nb_samples; i++, src++)
141  update_stat(s, p, *src);
142  }
143  break;
144  case AV_SAMPLE_FMT_FLT: {
145  const float *src = (const float *)buf->extended_data[0];
146 
147  for (i = 0; i < buf->nb_samples; i++) {
148  for (c = 0; c < channels; c++, src++)
149  update_stat(s, &s->chstats[c], *src);
150  }}
151  break;
152  }
153 
154  return ff_filter_frame(inlink->dst->outputs[0], buf);
155 }
156 
157 #define SQR(a) ((a)*(a))
158 
160 {
161  DRMeterContext *s = ctx->priv;
162  float dr = 0;
163  int ch;
164 
165  for (ch = 0; ch < s->nb_channels; ch++) {
166  ChannelStats *p = &s->chstats[ch];
167  float chdr, secondpeak, rmssum = 0;
168  int i, j, first = 0;
169 
170  finish_block(p);
171 
172  for (i = 0; i <= 10000; i++) {
173  if (p->peaks[10000 - i]) {
174  if (first)
175  break;
176  first = 1;
177  }
178  }
179 
180  secondpeak = (10000 - i) / 10000.;
181 
182  for (i = 10000, j = 0; i >= 0 && j < 0.2 * p->blknum; i--) {
183  if (p->rms[i]) {
184  rmssum += SQR(i / 10000.) * p->rms[i];
185  j += p->rms[i];
186  }
187  }
188 
189  chdr = 20 * log10(secondpeak / sqrt(rmssum / (0.2 * p->blknum)));
190  dr += chdr;
191  av_log(ctx, AV_LOG_INFO, "Channel %d: DR: %.1f\n", ch + 1, chdr);
192  }
193 
194  av_log(ctx, AV_LOG_INFO, "Overall DR: %.1f\n", dr / s->nb_channels);
195 }
196 
198 {
199  DRMeterContext *s = ctx->priv;
200 
201  if (s->nb_channels)
202  print_stats(ctx);
203  av_freep(&s->chstats);
204 }
205 
206 static const AVFilterPad drmeter_inputs[] = {
207  {
208  .name = "default",
209  .type = AVMEDIA_TYPE_AUDIO,
210  .filter_frame = filter_frame,
211  },
212  { NULL }
213 };
214 
215 static const AVFilterPad drmeter_outputs[] = {
216  {
217  .name = "default",
218  .type = AVMEDIA_TYPE_AUDIO,
219  .config_props = config_output,
220  },
221  { NULL }
222 };
223 
225  .name = "drmeter",
226  .description = NULL_IF_CONFIG_SMALL("Measure audio dynamic range."),
227  .query_formats = query_formats,
228  .priv_size = sizeof(DRMeterContext),
229  .priv_class = &drmeter_class,
230  .uninit = uninit,
231  .inputs = drmeter_inputs,
232  .outputs = drmeter_outputs,
233 };
float, planar
Definition: samplefmt.h:69
static void update_stat(DRMeterContext *s, ChannelStats *p, float sample)
Definition: af_drmeter.c:117
#define NULL
Definition: coverity.c:32
int ff_set_common_channel_layouts(AVFilterContext *ctx, AVFilterChannelLayouts *layouts)
A helper for query_formats() which sets all links to the same list of channel layouts/sample rates...
Definition: formats.c:550
This structure describes decoded (raw) audio or video data.
Definition: frame.h:295
static int config_output(AVFilterLink *outlink)
Definition: af_drmeter.c:86
AVOption.
Definition: opt.h:246
Main libavfilter public API header.
channels
Definition: aptx.c:30
AVFilter ff_af_drmeter
Definition: af_drmeter.c:224
#define OFFSET(x)
Definition: af_drmeter.c:46
#define src
Definition: vp8dsp.c:254
#define sample
void * av_calloc(size_t nmemb, size_t size)
Non-inlined equivalent of av_mallocz_array().
Definition: mem.c:244
AVFilterFormats * ff_make_format_list(const int *fmts)
Create a list of supported formats.
Definition: formats.c:283
static void print_stats(AVFilterContext *ctx)
Definition: af_drmeter.c:159
const char * name
Pad name.
Definition: internal.h:60
#define SQR(a)
Definition: af_drmeter.c:157
int ff_filter_frame(AVFilterLink *link, AVFrame *frame)
Send a frame of data to the next filter.
Definition: avfilter.c:1093
#define av_cold
Definition: attributes.h:82
static void finish_block(ChannelStats *p)
Definition: af_drmeter.c:99
AVOptions.
Undefined Behavior In the C some operations are like signed integer dereferencing freed accessing outside allocated Undefined Behavior must not occur in a C it is not safe even if the output of undefined operations is unused The unsafety may seem nit picking but Optimizing compilers have in fact optimized code on the assumption that no undefined Behavior occurs Optimizing code based on wrong assumptions can and has in some cases lead to effects beyond the output of computations The signed integer overflow problem in speed critical code Code which is highly optimized and works with signed integers sometimes has the problem that often the output of the computation does not c
Definition: undefined.txt:32
trying all byte sequences megabyte in length and selecting the best looking sequence will yield cases to try But first
uint64_t tc_samples
Definition: af_drmeter.c:42
double time_constant
Definition: af_drmeter.c:43
#define av_log(a,...)
A filter pad used for either input or output.
Definition: internal.h:54
#define i(width, name, range_min, range_max)
Definition: cbs_h2645.c:259
int ff_set_common_formats(AVFilterContext *ctx, AVFilterFormats *formats)
A helper for query_formats() which sets all links to the same list of formats.
Definition: formats.c:569
#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 FFMAX(a, b)
Definition: common.h:94
AVFormatContext * ctx
Definition: movenc.c:48
AVFILTER_DEFINE_CLASS(drmeter)
#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
static int query_formats(AVFilterContext *ctx)
Definition: af_drmeter.c:56
A list of supported channel layouts.
Definition: formats.h:85
uint32_t rms[10001]
Definition: af_drmeter.c:35
#define AV_LOG_INFO
Standard information.
Definition: log.h:187
AVSampleFormat
Audio sample formats.
Definition: samplefmt.h:58
void * buf
Definition: avisynth_c.h:766
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
const char * name
Filter name.
Definition: avfilter.h:148
static const AVOption drmeter_options[]
Definition: af_drmeter.c:49
AVFilterLink ** outputs
array of pointers to output links
Definition: avfilter.h:350
enum MovChannelLayoutTag * layouts
Definition: mov_chan.c:434
uint8_t pi<< 24) CONV_FUNC(AV_SAMPLE_FMT_S64, int64_t, AV_SAMPLE_FMT_U8,(uint64_t)((*(const uint8_t *) pi-0x80U))<< 56) CONV_FUNC(AV_SAMPLE_FMT_FLT, float, AV_SAMPLE_FMT_U8,(*(const uint8_t *) pi-0x80)*(1.0f/(1<< 7))) CONV_FUNC(AV_SAMPLE_FMT_DBL, double, AV_SAMPLE_FMT_U8,(*(const uint8_t *) pi-0x80)*(1.0/(1<< 7))) CONV_FUNC(AV_SAMPLE_FMT_U8, uint8_t, AV_SAMPLE_FMT_S16,(*(const int16_t *) pi >>8)+0x80) CONV_FUNC(AV_SAMPLE_FMT_S64, int64_t, AV_SAMPLE_FMT_S16,(uint64_t)(*(const int16_t *) pi)<< 48) CONV_FUNC(AV_SAMPLE_FMT_FLT, float, AV_SAMPLE_FMT_S16,*(const int16_t *) pi *(1.0f/(1<< 15))) CONV_FUNC(AV_SAMPLE_FMT_DBL, double, AV_SAMPLE_FMT_S16,*(const int16_t *) pi *(1.0/(1<< 15))) CONV_FUNC(AV_SAMPLE_FMT_U8, uint8_t, AV_SAMPLE_FMT_S32,(*(const int32_t *) pi >>24)+0x80) CONV_FUNC(AV_SAMPLE_FMT_S64, int64_t, AV_SAMPLE_FMT_S32,(uint64_t)(*(const int32_t *) pi)<< 32) CONV_FUNC(AV_SAMPLE_FMT_FLT, float, AV_SAMPLE_FMT_S32,*(const int32_t *) pi *(1.0f/(1U<< 31))) CONV_FUNC(AV_SAMPLE_FMT_DBL, double, AV_SAMPLE_FMT_S32,*(const int32_t *) pi *(1.0/(1U<< 31))) CONV_FUNC(AV_SAMPLE_FMT_U8, uint8_t, AV_SAMPLE_FMT_S64,(*(const int64_t *) pi >>56)+0x80) CONV_FUNC(AV_SAMPLE_FMT_FLT, float, AV_SAMPLE_FMT_S64,*(const int64_t *) pi *(1.0f/(UINT64_C(1)<< 63))) CONV_FUNC(AV_SAMPLE_FMT_DBL, double, AV_SAMPLE_FMT_S64,*(const int64_t *) pi *(1.0/(UINT64_C(1)<< 63))) CONV_FUNC(AV_SAMPLE_FMT_U8, uint8_t, AV_SAMPLE_FMT_FLT, av_clip_uint8(lrintf(*(const float *) pi *(1<< 7))+0x80)) CONV_FUNC(AV_SAMPLE_FMT_S16, int16_t, AV_SAMPLE_FMT_FLT, av_clip_int16(lrintf(*(const float *) pi *(1<< 15)))) CONV_FUNC(AV_SAMPLE_FMT_S32, int32_t, AV_SAMPLE_FMT_FLT, av_clipl_int32(llrintf(*(const float *) pi *(1U<< 31)))) CONV_FUNC(AV_SAMPLE_FMT_S64, int64_t, AV_SAMPLE_FMT_FLT, llrintf(*(const float *) pi *(UINT64_C(1)<< 63))) CONV_FUNC(AV_SAMPLE_FMT_U8, uint8_t, AV_SAMPLE_FMT_DBL, av_clip_uint8(lrint(*(const double *) pi *(1<< 7))+0x80)) CONV_FUNC(AV_SAMPLE_FMT_S16, int16_t, AV_SAMPLE_FMT_DBL, av_clip_int16(lrint(*(const double *) pi *(1<< 15)))) CONV_FUNC(AV_SAMPLE_FMT_S32, int32_t, AV_SAMPLE_FMT_DBL, av_clipl_int32(llrint(*(const double *) pi *(1U<< 31)))) CONV_FUNC(AV_SAMPLE_FMT_S64, int64_t, AV_SAMPLE_FMT_DBL, llrint(*(const double *) pi *(UINT64_C(1)<< 63)))#define FMT_PAIR_FUNC(out, in) static conv_func_type *const fmt_pair_to_conv_functions[AV_SAMPLE_FMT_NB *AV_SAMPLE_FMT_NB]={FMT_PAIR_FUNC(AV_SAMPLE_FMT_U8, AV_SAMPLE_FMT_U8), FMT_PAIR_FUNC(AV_SAMPLE_FMT_S16, AV_SAMPLE_FMT_U8), FMT_PAIR_FUNC(AV_SAMPLE_FMT_S32, AV_SAMPLE_FMT_U8), FMT_PAIR_FUNC(AV_SAMPLE_FMT_FLT, AV_SAMPLE_FMT_U8), FMT_PAIR_FUNC(AV_SAMPLE_FMT_DBL, AV_SAMPLE_FMT_U8), FMT_PAIR_FUNC(AV_SAMPLE_FMT_S64, AV_SAMPLE_FMT_U8), FMT_PAIR_FUNC(AV_SAMPLE_FMT_U8, AV_SAMPLE_FMT_S16), FMT_PAIR_FUNC(AV_SAMPLE_FMT_S16, AV_SAMPLE_FMT_S16), FMT_PAIR_FUNC(AV_SAMPLE_FMT_S32, AV_SAMPLE_FMT_S16), FMT_PAIR_FUNC(AV_SAMPLE_FMT_FLT, AV_SAMPLE_FMT_S16), FMT_PAIR_FUNC(AV_SAMPLE_FMT_DBL, AV_SAMPLE_FMT_S16), FMT_PAIR_FUNC(AV_SAMPLE_FMT_S64, AV_SAMPLE_FMT_S16), FMT_PAIR_FUNC(AV_SAMPLE_FMT_U8, AV_SAMPLE_FMT_S32), FMT_PAIR_FUNC(AV_SAMPLE_FMT_S16, AV_SAMPLE_FMT_S32), FMT_PAIR_FUNC(AV_SAMPLE_FMT_S32, AV_SAMPLE_FMT_S32), FMT_PAIR_FUNC(AV_SAMPLE_FMT_FLT, AV_SAMPLE_FMT_S32), FMT_PAIR_FUNC(AV_SAMPLE_FMT_DBL, AV_SAMPLE_FMT_S32), FMT_PAIR_FUNC(AV_SAMPLE_FMT_S64, AV_SAMPLE_FMT_S32), FMT_PAIR_FUNC(AV_SAMPLE_FMT_U8, AV_SAMPLE_FMT_FLT), FMT_PAIR_FUNC(AV_SAMPLE_FMT_S16, AV_SAMPLE_FMT_FLT), FMT_PAIR_FUNC(AV_SAMPLE_FMT_S32, AV_SAMPLE_FMT_FLT), FMT_PAIR_FUNC(AV_SAMPLE_FMT_FLT, AV_SAMPLE_FMT_FLT), FMT_PAIR_FUNC(AV_SAMPLE_FMT_DBL, AV_SAMPLE_FMT_FLT), FMT_PAIR_FUNC(AV_SAMPLE_FMT_S64, AV_SAMPLE_FMT_FLT), FMT_PAIR_FUNC(AV_SAMPLE_FMT_U8, AV_SAMPLE_FMT_DBL), FMT_PAIR_FUNC(AV_SAMPLE_FMT_S16, AV_SAMPLE_FMT_DBL), FMT_PAIR_FUNC(AV_SAMPLE_FMT_S32, AV_SAMPLE_FMT_DBL), FMT_PAIR_FUNC(AV_SAMPLE_FMT_FLT, AV_SAMPLE_FMT_DBL), FMT_PAIR_FUNC(AV_SAMPLE_FMT_DBL, AV_SAMPLE_FMT_DBL), FMT_PAIR_FUNC(AV_SAMPLE_FMT_S64, AV_SAMPLE_FMT_DBL), FMT_PAIR_FUNC(AV_SAMPLE_FMT_U8, AV_SAMPLE_FMT_S64), FMT_PAIR_FUNC(AV_SAMPLE_FMT_S16, AV_SAMPLE_FMT_S64), FMT_PAIR_FUNC(AV_SAMPLE_FMT_S32, AV_SAMPLE_FMT_S64), FMT_PAIR_FUNC(AV_SAMPLE_FMT_FLT, AV_SAMPLE_FMT_S64), FMT_PAIR_FUNC(AV_SAMPLE_FMT_DBL, AV_SAMPLE_FMT_S64), FMT_PAIR_FUNC(AV_SAMPLE_FMT_S64, AV_SAMPLE_FMT_S64),};static void cpy1(uint8_t **dst, const uint8_t **src, int len){memcpy(*dst,*src, len);}static void cpy2(uint8_t **dst, const uint8_t **src, int len){memcpy(*dst,*src, 2 *len);}static void cpy4(uint8_t **dst, const uint8_t **src, int len){memcpy(*dst,*src, 4 *len);}static void cpy8(uint8_t **dst, const uint8_t **src, int len){memcpy(*dst,*src, 8 *len);}AudioConvert *swri_audio_convert_alloc(enum AVSampleFormat out_fmt, enum AVSampleFormat in_fmt, int channels, const int *ch_map, int flags){AudioConvert *ctx;conv_func_type *f=fmt_pair_to_conv_functions[av_get_packed_sample_fmt(out_fmt)+AV_SAMPLE_FMT_NB *av_get_packed_sample_fmt(in_fmt)];if(!f) return NULL;ctx=av_mallocz(sizeof(*ctx));if(!ctx) return NULL;if(channels==1){in_fmt=av_get_planar_sample_fmt(in_fmt);out_fmt=av_get_planar_sample_fmt(out_fmt);}ctx->channels=channels;ctx->conv_f=f;ctx->ch_map=ch_map;if(in_fmt==AV_SAMPLE_FMT_U8||in_fmt==AV_SAMPLE_FMT_U8P) memset(ctx->silence, 0x80, sizeof(ctx->silence));if(out_fmt==in_fmt &&!ch_map){switch(av_get_bytes_per_sample(in_fmt)){case 1:ctx->simd_f=cpy1;break;case 2:ctx->simd_f=cpy2;break;case 4:ctx->simd_f=cpy4;break;case 8:ctx->simd_f=cpy8;break;}}if(HAVE_X86ASM &&1) swri_audio_convert_init_x86(ctx, out_fmt, in_fmt, channels);if(ARCH_ARM) swri_audio_convert_init_arm(ctx, out_fmt, in_fmt, channels);if(ARCH_AARCH64) swri_audio_convert_init_aarch64(ctx, out_fmt, in_fmt, channels);return ctx;}void swri_audio_convert_free(AudioConvert **ctx){av_freep(ctx);}int swri_audio_convert(AudioConvert *ctx, AudioData *out, AudioData *in, int len){int ch;int off=0;const int os=(out->planar?1:out->ch_count)*out->bps;unsigned misaligned=0;av_assert0(ctx->channels==out->ch_count);if(ctx->in_simd_align_mask){int planes=in->planar?in->ch_count:1;unsigned m=0;for(ch=0;ch< planes;ch++) m|=(intptr_t) in->ch[ch];misaligned|=m &ctx->in_simd_align_mask;}if(ctx->out_simd_align_mask){int planes=out->planar?out->ch_count:1;unsigned m=0;for(ch=0;ch< planes;ch++) m|=(intptr_t) out->ch[ch];misaligned|=m &ctx->out_simd_align_mask;}if(ctx->simd_f &&!ctx->ch_map &&!misaligned){off=len &~15;av_assert1(off >=0);av_assert1(off<=len);av_assert2(ctx->channels==SWR_CH_MAX||!in->ch[ctx->channels]);if(off >0){if(out->planar==in->planar){int planes=out->planar?out->ch_count:1;for(ch=0;ch< planes;ch++){ctx->simd_f(out-> ch ch
Definition: audioconvert.c:56
AVFilterFormats * ff_all_samplerates(void)
Definition: formats.c:394
#define FLAGS
Definition: af_drmeter.c:47
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
internal math functions header
ChannelStats * chstats
Definition: af_drmeter.c:40
uint64_t nb_samples
Definition: af_astats.c:74
static int filter_frame(AVFilterLink *inlink, AVFrame *buf)
Definition: af_drmeter.c:128
A list of supported formats for one end of a filter link.
Definition: formats.h:64
static const AVFilterPad drmeter_inputs[]
Definition: af_drmeter.c:206
static av_cold void uninit(AVFilterContext *ctx)
Definition: af_drmeter.c:197
An instance of a filter.
Definition: avfilter.h:338
static enum AVSampleFormat sample_fmts[]
Definition: adpcmenc.c:701
#define av_freep(p)
formats
Definition: signature.h:48
static const AVFilterPad drmeter_outputs[]
Definition: af_drmeter.c:215
float peak
Definition: af_drmeter.c:32
internal API functions
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
AVFilterChannelLayouts * ff_all_channel_counts(void)
Construct an AVFilterChannelLayouts coding for any channel layout, with known or unknown disposition...
Definition: formats.c:409
uint8_t ** extended_data
pointers to the data planes/channels.
Definition: frame.h:342
uint64_t blknum
Definition: af_drmeter.c:31
uint32_t peaks[10001]
Definition: af_drmeter.c:34
int nb_samples
number of audio samples (per channel) described by this frame
Definition: frame.h:361
for(j=16;j >0;--j)
int ff_set_common_samplerates(AVFilterContext *ctx, AVFilterFormats *samplerates)
Definition: formats.c:557