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af_volumedetect.c
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1 /*
2  * Copyright (c) 2012 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 
22 #include "libavutil/avassert.h"
23 #include "audio.h"
24 #include "avfilter.h"
25 #include "internal.h"
26 
27 typedef struct {
28  /**
29  * Number of samples at each PCM value.
30  * histogram[0x8000 + i] is the number of samples at value i.
31  * The extra element is there for symmetry.
32  */
33  uint64_t histogram[0x10001];
35 
37 {
38  static const enum AVSampleFormat sample_fmts[] = {
42  };
45  int ret;
46 
47  if (!(formats = ff_make_format_list(sample_fmts)))
48  return AVERROR(ENOMEM);
49 
50  layouts = ff_all_channel_counts();
51  if (!layouts)
52  return AVERROR(ENOMEM);
53  ret = ff_set_common_channel_layouts(ctx, layouts);
54  if (ret < 0)
55  return ret;
56 
57  return ff_set_common_formats(ctx, formats);
58 }
59 
60 static int filter_frame(AVFilterLink *inlink, AVFrame *samples)
61 {
62  AVFilterContext *ctx = inlink->dst;
63  VolDetectContext *vd = ctx->priv;
64  int nb_samples = samples->nb_samples;
65  int nb_channels = av_frame_get_channels(samples);
66  int nb_planes = nb_channels;
67  int plane, i;
68  int16_t *pcm;
69 
70  if (!av_sample_fmt_is_planar(samples->format)) {
71  nb_samples *= nb_channels;
72  nb_planes = 1;
73  }
74  for (plane = 0; plane < nb_planes; plane++) {
75  pcm = (int16_t *)samples->extended_data[plane];
76  for (i = 0; i < nb_samples; i++)
77  vd->histogram[pcm[i] + 0x8000]++;
78  }
79 
80  return ff_filter_frame(inlink->dst->outputs[0], samples);
81 }
82 
83 #define MAX_DB 91
84 
85 static inline double logdb(uint64_t v)
86 {
87  double d = v / (double)(0x8000 * 0x8000);
88  if (!v)
89  return MAX_DB;
90  return -log10(d) * 10;
91 }
92 
94 {
95  VolDetectContext *vd = ctx->priv;
96  int i, max_volume, shift;
97  uint64_t nb_samples = 0, power = 0, nb_samples_shift = 0, sum = 0;
98  uint64_t histdb[MAX_DB + 1] = { 0 };
99 
100  for (i = 0; i < 0x10000; i++)
101  nb_samples += vd->histogram[i];
102  av_log(ctx, AV_LOG_INFO, "n_samples: %"PRId64"\n", nb_samples);
103  if (!nb_samples)
104  return;
105 
106  /* If nb_samples > 1<<34, there is a risk of overflow in the
107  multiplication or the sum: shift all histogram values to avoid that.
108  The total number of samples must be recomputed to avoid rounding
109  errors. */
110  shift = av_log2(nb_samples >> 33);
111  for (i = 0; i < 0x10000; i++) {
112  nb_samples_shift += vd->histogram[i] >> shift;
113  power += (i - 0x8000) * (i - 0x8000) * (vd->histogram[i] >> shift);
114  }
115  if (!nb_samples_shift)
116  return;
117  power = (power + nb_samples_shift / 2) / nb_samples_shift;
118  av_assert0(power <= 0x8000 * 0x8000);
119  av_log(ctx, AV_LOG_INFO, "mean_volume: %.1f dB\n", -logdb(power));
120 
121  max_volume = 0x8000;
122  while (max_volume > 0 && !vd->histogram[0x8000 + max_volume] &&
123  !vd->histogram[0x8000 - max_volume])
124  max_volume--;
125  av_log(ctx, AV_LOG_INFO, "max_volume: %.1f dB\n", -logdb(max_volume * max_volume));
126 
127  for (i = 0; i < 0x10000; i++)
128  histdb[(int)logdb((i - 0x8000) * (i - 0x8000))] += vd->histogram[i];
129  for (i = 0; i <= MAX_DB && !histdb[i]; i++);
130  for (; i <= MAX_DB && sum < nb_samples / 1000; i++) {
131  av_log(ctx, AV_LOG_INFO, "histogram_%ddb: %"PRId64"\n", i, histdb[i]);
132  sum += histdb[i];
133  }
134 }
135 
137 {
138  print_stats(ctx);
139 }
140 
142  {
143  .name = "default",
144  .type = AVMEDIA_TYPE_AUDIO,
145  .filter_frame = filter_frame,
146  },
147  { NULL }
148 };
149 
151  {
152  .name = "default",
153  .type = AVMEDIA_TYPE_AUDIO,
154  },
155  { NULL }
156 };
157 
159  .name = "volumedetect",
160  .description = NULL_IF_CONFIG_SMALL("Detect audio volume."),
161  .priv_size = sizeof(VolDetectContext),
163  .uninit = uninit,
164  .inputs = volumedetect_inputs,
165  .outputs = volumedetect_outputs,
166 };
int plane
Definition: avisynth_c.h:422
#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:549
static int shift(int a, int b)
Definition: sonic.c:82
This structure describes decoded (raw) audio or video data.
Definition: frame.h:184
Main libavfilter public API header.
static enum AVSampleFormat formats[]
Definition: avresample.c:163
int av_log2(unsigned v)
Definition: intmath.c:26
static double logdb(uint64_t v)
AVFilterFormats * ff_make_format_list(const int *fmts)
Create a list of supported formats.
Definition: formats.c:283
static int query_formats(AVFilterContext *ctx)
const char * name
Pad name.
Definition: internal.h:59
#define av_assert0(cond)
assert() equivalent, that is always enabled.
Definition: avassert.h:37
int ff_filter_frame(AVFilterLink *link, AVFrame *frame)
Send a frame of data to the next filter.
Definition: avfilter.c:1189
#define av_cold
Definition: attributes.h:82
uint64_t histogram[0x10001]
Number of samples at each PCM value.
static int filter_frame(AVFilterLink *inlink, AVFrame *samples)
#define av_log(a,...)
int av_sample_fmt_is_planar(enum AVSampleFormat sample_fmt)
Check if the sample format is planar.
Definition: samplefmt.c:112
A filter pad used for either input or output.
Definition: internal.h:53
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:568
static const AVFilterPad volumedetect_outputs[]
#define AVERROR(e)
Definition: error.h:43
static av_cold void uninit(AVFilterContext *ctx)
#define NULL_IF_CONFIG_SMALL(x)
Return NULL if CONFIG_SMALL is true, otherwise the argument without modification. ...
Definition: internal.h:176
void * priv
private data for use by the filter
Definition: avfilter.h:322
simple assert() macros that are a bit more flexible than ISO C assert().
static void print_stats(AVFilterContext *ctx)
#define MAX_DB
audio channel layout utility functions
AVFormatContext * ctx
Definition: movenc.c:48
static const AVFilterPad outputs[]
Definition: af_afftfilt.c:386
A list of supported channel layouts.
Definition: formats.h:85
int format
format of the frame, -1 if unknown or unset Values correspond to enum AVPixelFormat for video frames...
Definition: frame.h:248
#define AV_LOG_INFO
Standard information.
Definition: log.h:187
static const AVFilterPad inputs[]
Definition: af_afftfilt.c:376
AVSampleFormat
Audio sample formats.
Definition: samplefmt.h:58
int av_frame_get_channels(const AVFrame *frame)
Filter definition.
Definition: avfilter.h:144
static const AVFilterPad volumedetect_inputs[]
const char * name
Filter name.
Definition: avfilter.h:148
AVFilterLink ** outputs
array of pointers to output links
Definition: avfilter.h:319
enum MovChannelLayoutTag * layouts
Definition: mov_chan.c:434
signed 16 bits
Definition: samplefmt.h:61
AVFilter ff_af_volumedetect
A list of supported formats for one end of a filter link.
Definition: formats.h:64
An instance of a filter.
Definition: avfilter.h:307
static enum AVSampleFormat sample_fmts[]
Definition: adpcmenc.c:701
signed 16 bits, planar
Definition: samplefmt.h:67
int nb_channels
internal API functions
AVFilterChannelLayouts * ff_all_channel_counts(void)
Construct an AVFilterChannelLayouts coding for any channel layout, with known or unknown disposition...
Definition: formats.c:410
uint8_t ** extended_data
pointers to the data planes/channels.
Definition: frame.h:231
int nb_samples
number of audio samples (per channel) described by this frame
Definition: frame.h:241
for(j=16;j >0;--j)