FFmpeg
af_drmeter.c
Go to the documentation of this file.
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 #define BINS 32768
30 
31 typedef struct ChannelStats {
32  uint64_t nb_samples;
33  uint64_t blknum;
34  float peak;
35  float sum;
36  uint32_t peaks[BINS+1];
37  uint32_t rms[BINS+1];
38 } ChannelStats;
39 
40 typedef struct DRMeterContext {
41  const AVClass *class;
44  int64_t tc_samples;
45  double time_constant;
47 
48 #define OFFSET(x) offsetof(DRMeterContext, x)
49 #define FLAGS AV_OPT_FLAG_AUDIO_PARAM|AV_OPT_FLAG_FILTERING_PARAM
50 
51 static const AVOption drmeter_options[] = {
52  { "length", "set the window length", OFFSET(time_constant), AV_OPT_TYPE_DOUBLE, {.dbl=3}, .01, 10, FLAGS },
53  { NULL }
54 };
55 
56 AVFILTER_DEFINE_CLASS(drmeter);
57 
58 static int config_output(AVFilterLink *outlink)
59 {
60  DRMeterContext *s = outlink->src->priv;
61 
62  s->chstats = av_calloc(outlink->ch_layout.nb_channels, sizeof(*s->chstats));
63  if (!s->chstats)
64  return AVERROR(ENOMEM);
65  s->nb_channels = outlink->ch_layout.nb_channels;
66  s->tc_samples = lrint(s->time_constant * outlink->sample_rate);
67 
68  return 0;
69 }
70 
71 static void finish_block(ChannelStats *p)
72 {
73  int peak_bin, rms_bin;
74  float peak, rms;
75 
76  rms = sqrtf(2.f * p->sum / p->nb_samples);
77  peak = p->peak;
78  rms_bin = av_clip(lrintf(rms * BINS), 0, BINS);
79  peak_bin = av_clip(lrintf(peak * BINS), 0, BINS);
80  p->rms[rms_bin]++;
81  p->peaks[peak_bin]++;
82 
83  p->peak = 0;
84  p->sum = 0;
85  p->nb_samples = 0;
86  p->blknum++;
87 }
88 
90 {
91  p->peak = fmaxf(fabsf(sample), p->peak);
92  p->sum += sample * sample;
93  p->nb_samples++;
94  if (p->nb_samples >= s->tc_samples)
95  finish_block(p);
96 }
97 
99 {
100  DRMeterContext *s = inlink->dst->priv;
101  const int channels = s->nb_channels;
102 
103  switch (inlink->format) {
104  case AV_SAMPLE_FMT_FLTP:
105  for (int c = 0; c < channels; c++) {
106  ChannelStats *p = &s->chstats[c];
107  const float *src = (const float *)buf->extended_data[c];
108 
109  for (int i = 0; i < buf->nb_samples; i++, src++)
110  update_stat(s, p, *src);
111  }
112  break;
113  case AV_SAMPLE_FMT_FLT: {
114  const float *src = (const float *)buf->extended_data[0];
115 
116  for (int i = 0; i < buf->nb_samples; i++) {
117  for (int c = 0; c < channels; c++, src++)
118  update_stat(s, &s->chstats[c], *src);
119  }}
120  break;
121  }
122 
123  return ff_filter_frame(inlink->dst->outputs[0], buf);
124 }
125 
126 #define SQR(a) ((a)*(a))
127 
129 {
130  DRMeterContext *s = ctx->priv;
131  float dr = 0.f;
132 
133  for (int ch = 0; ch < s->nb_channels; ch++) {
134  ChannelStats *p = &s->chstats[ch];
135  float chdr, secondpeak, rmssum = 0.f;
136  int first = 0, last = lrintf(0.2f * p->blknum);
137  int peak_bin = BINS;
138 
139  if (!p->nb_samples) {
140  av_log(ctx, AV_LOG_INFO, "No data, dynamic range not meassurable\n");
141  return;
142  }
143 
144  if (p->nb_samples)
145  finish_block(p);
146 
147  for (int i = BINS; i >= 0; i--) {
148  if (p->peaks[i]) {
149  if (first || p->peaks[i] > 1) {
150  peak_bin = i;
151  break;
152  }
153  first = 1;
154  }
155  }
156 
157  secondpeak = peak_bin / (float)BINS;
158 
159  for (int64_t i = BINS, j = 0; i >= 0 && j < last; i--) {
160  if (p->rms[i]) {
161  rmssum += SQR(i / (float)BINS) * p->rms[i];
162  j += p->rms[i];
163  }
164  }
165 
166  chdr = 20.f * log10f(secondpeak / sqrtf(rmssum / (float)last));
167  dr += chdr;
168  av_log(ctx, AV_LOG_INFO, "Channel %d: DR: %g\n", ch + 1, chdr);
169  }
170 
171  av_log(ctx, AV_LOG_INFO, "Overall DR: %g\n", dr / s->nb_channels);
172 }
173 
175 {
176  DRMeterContext *s = ctx->priv;
177 
178  if (s->nb_channels)
179  print_stats(ctx);
180  av_freep(&s->chstats);
181 }
182 
183 static const AVFilterPad drmeter_inputs[] = {
184  {
185  .name = "default",
186  .type = AVMEDIA_TYPE_AUDIO,
187  .filter_frame = filter_frame,
188  },
189 };
190 
191 static const AVFilterPad drmeter_outputs[] = {
192  {
193  .name = "default",
194  .type = AVMEDIA_TYPE_AUDIO,
195  .config_props = config_output,
196  },
197 };
198 
200  .name = "drmeter",
201  .description = NULL_IF_CONFIG_SMALL("Measure audio dynamic range."),
202  .priv_size = sizeof(DRMeterContext),
203  .priv_class = &drmeter_class,
204  .uninit = uninit,
209 };
AV_SAMPLE_FMT_FLTP
@ AV_SAMPLE_FMT_FLTP
float, planar
Definition: samplefmt.h:66
uninit
static av_cold void uninit(AVFilterContext *ctx)
Definition: af_drmeter.c:174
av_clip
#define av_clip
Definition: common.h:98
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
finish_block
static void finish_block(ChannelStats *p)
Definition: af_drmeter.c:71
ff_filter_frame
int ff_filter_frame(AVFilterLink *link, AVFrame *frame)
Send a frame of data to the next filter.
Definition: avfilter.c:1007
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
filter_frame
static int filter_frame(AVFilterLink *inlink, AVFrame *buf)
Definition: af_drmeter.c:98
AVFrame
This structure describes decoded (raw) audio or video data.
Definition: frame.h:340
AVOption
AVOption.
Definition: opt.h:251
float.h
AVFilter::name
const char * name
Filter name.
Definition: avfilter.h:170
DRMeterContext::time_constant
double time_constant
Definition: af_drmeter.c:45
AVChannelLayout::nb_channels
int nb_channels
Number of channels in this layout.
Definition: channel_layout.h:323
DRMeterContext::chstats
ChannelStats * chstats
Definition: af_drmeter.c:42
AVFILTER_DEFINE_CLASS
AVFILTER_DEFINE_CLASS(drmeter)
AVFilterContext::priv
void * priv
private data for use by the filter
Definition: avfilter.h:424
log10f
#define log10f(x)
Definition: libm.h:414
fabsf
static __device__ float fabsf(float a)
Definition: cuda_runtime.h:181
AVFilterPad
A filter pad used for either input or output.
Definition: internal.h:33
update_stat
static void update_stat(DRMeterContext *s, ChannelStats *p, float sample)
Definition: af_drmeter.c:89
first
trying all byte sequences megabyte in length and selecting the best looking sequence will yield cases to try But first
Definition: rate_distortion.txt:12
lrint
#define lrint
Definition: tablegen.h:53
av_cold
#define av_cold
Definition: attributes.h:90
float
float
Definition: af_crystalizer.c:121
print_stats
static void print_stats(AVFilterContext *ctx)
Definition: af_drmeter.c:128
s
#define s(width, name)
Definition: cbs_vp9.c:198
ChannelStats::peaks
uint32_t peaks[BINS+1]
Definition: af_drmeter.c:36
AV_OPT_TYPE_DOUBLE
@ AV_OPT_TYPE_DOUBLE
Definition: opt.h:227
AVMEDIA_TYPE_AUDIO
@ AVMEDIA_TYPE_AUDIO
Definition: avutil.h:202
ctx
AVFormatContext * ctx
Definition: movenc.c:48
channels
channels
Definition: aptx.h:31
SQR
#define SQR(a)
Definition: af_drmeter.c:126
FILTER_INPUTS
#define FILTER_INPUTS(array)
Definition: internal.h:182
AVClass
Describe the class of an AVClass context structure.
Definition: log.h:66
NULL
#define NULL
Definition: coverity.c:32
DRMeterContext::tc_samples
int64_t tc_samples
Definition: af_drmeter.c:44
sqrtf
static __device__ float sqrtf(float a)
Definition: cuda_runtime.h:184
ChannelStats::rms
uint32_t rms[BINS+1]
Definition: af_drmeter.c:37
config_output
static int config_output(AVFilterLink *outlink)
Definition: af_drmeter.c:58
DRMeterContext
Definition: af_drmeter.c:40
c
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
drmeter_options
static const AVOption drmeter_options[]
Definition: af_drmeter.c:51
f
f
Definition: af_crystalizer.c:121
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:106
for
for(k=2;k<=8;++k)
Definition: h264pred_template.c:425
fmaxf
float fmaxf(float, float)
ff_af_drmeter
const AVFilter ff_af_drmeter
Definition: af_drmeter.c:199
sample
#define sample
Definition: flacdsp_template.c:44
ChannelStats::nb_samples
uint64_t nb_samples
Definition: af_astats.c:84
FLAGS
#define FLAGS
Definition: af_drmeter.c:49
OFFSET
#define OFFSET(x)
Definition: af_drmeter.c:48
AV_LOG_INFO
#define AV_LOG_INFO
Standard information.
Definition: log.h:191
internal.h
DRMeterContext::nb_channels
int nb_channels
Definition: af_drmeter.c:43
AVFrame::nb_samples
int nb_samples
number of audio samples (per channel) described by this frame
Definition: frame.h:420
ChannelStats
Definition: af_astats.c:65
lrintf
#define lrintf(x)
Definition: libm_mips.h:72
i
#define i(width, name, range_min, range_max)
Definition: cbs_h2645.c:255
AVFrame::extended_data
uint8_t ** extended_data
pointers to the data planes/channels.
Definition: frame.h:401
AVFilterPad::name
const char * name
Pad name.
Definition: internal.h:39
av_calloc
void * av_calloc(size_t nmemb, size_t size)
Definition: mem.c:262
AVFilter
Filter definition.
Definition: avfilter.h:166
BINS
#define BINS
Definition: af_drmeter.c:29
avfilter.h
AVFILTER_FLAG_METADATA_ONLY
#define AVFILTER_FLAG_METADATA_ONLY
The filter is a "metadata" filter - it does not modify the frame data in any way.
Definition: avfilter.h:133
ffmath.h
AVFilterContext
An instance of a filter.
Definition: avfilter.h:409
audio.h
FILTER_OUTPUTS
#define FILTER_OUTPUTS(array)
Definition: internal.h:183
av_freep
#define av_freep(p)
Definition: tableprint_vlc.h:34
src
INIT_CLIP pixel * src
Definition: h264pred_template.c:418
ChannelStats::peak
float peak
Definition: af_drmeter.c:34
flags
#define flags(name, subs,...)
Definition: cbs_av1.c:474
ChannelStats::blknum
uint64_t blknum
Definition: af_drmeter.c:33
av_log
#define av_log(a,...)
Definition: tableprint_vlc.h:27
drmeter_outputs
static const AVFilterPad drmeter_outputs[]
Definition: af_drmeter.c:191
ChannelStats::sum
float sum
Definition: af_drmeter.c:35
AV_SAMPLE_FMT_FLT
@ AV_SAMPLE_FMT_FLT
float
Definition: samplefmt.h:60
drmeter_inputs
static const AVFilterPad drmeter_inputs[]
Definition: af_drmeter.c:183
FILTER_SAMPLEFMTS
#define FILTER_SAMPLEFMTS(...)
Definition: internal.h:170