1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
|
/*
* Copyright (c) 2012 Nicolas George
*
* This file is part of FFmpeg.
*
* FFmpeg is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public License
* as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* FFmpeg is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with FFmpeg; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include "libavutil/channel_layout.h"
#include "libavutil/avassert.h"
#include "audio.h"
#include "avfilter.h"
#include "internal.h"
typedef struct {
/**
* Number of samples at each PCM value.
* histogram[0x8000 + i] is the number of samples at value i.
* The extra element is there for symmetry.
*/
uint64_t histogram[0x10001];
} VolDetectContext;
static int query_formats(AVFilterContext *ctx)
{
static const enum AVSampleFormat sample_fmts[] = {
AV_SAMPLE_FMT_S16,
AV_SAMPLE_FMT_S16P,
AV_SAMPLE_FMT_NONE
};
AVFilterFormats *formats;
if (!(formats = ff_make_format_list(sample_fmts)))
return AVERROR(ENOMEM);
ff_set_common_formats(ctx, formats);
return 0;
}
static int filter_frame(AVFilterLink *inlink, AVFrame *samples)
{
AVFilterContext *ctx = inlink->dst;
VolDetectContext *vd = ctx->priv;
int64_t layout = samples->channel_layout;
int nb_samples = samples->nb_samples;
int nb_channels = av_get_channel_layout_nb_channels(layout);
int nb_planes = nb_channels;
int plane, i;
int16_t *pcm;
if (!av_sample_fmt_is_planar(samples->format)) {
nb_samples *= nb_channels;
nb_planes = 1;
}
for (plane = 0; plane < nb_planes; plane++) {
pcm = (int16_t *)samples->extended_data[plane];
for (i = 0; i < nb_samples; i++)
vd->histogram[pcm[i] + 0x8000]++;
}
return ff_filter_frame(inlink->dst->outputs[0], samples);
}
#define MAX_DB 91
static inline double logdb(uint64_t v)
{
double d = v / (double)(0x8000 * 0x8000);
if (!v)
return MAX_DB;
return log(d) * -4.3429448190325182765112891891660508229; /* -10/log(10) */
}
static void print_stats(AVFilterContext *ctx)
{
VolDetectContext *vd = ctx->priv;
int i, max_volume, shift;
uint64_t nb_samples = 0, power = 0, nb_samples_shift = 0, sum = 0;
uint64_t histdb[MAX_DB + 1] = { 0 };
for (i = 0; i < 0x10000; i++)
nb_samples += vd->histogram[i];
av_log(ctx, AV_LOG_INFO, "n_samples: %"PRId64"\n", nb_samples);
if (!nb_samples)
return;
/* If nb_samples > 1<<34, there is a risk of overflow in the
multiplication or the sum: shift all histogram values to avoid that.
The total number of samples must be recomputed to avoid rounding
errors. */
shift = av_log2(nb_samples >> 33);
for (i = 0; i < 0x10000; i++) {
nb_samples_shift += vd->histogram[i] >> shift;
power += (i - 0x8000) * (i - 0x8000) * (vd->histogram[i] >> shift);
}
if (!nb_samples_shift)
return;
power = (power + nb_samples_shift / 2) / nb_samples_shift;
av_assert0(power <= 0x8000 * 0x8000);
av_log(ctx, AV_LOG_INFO, "mean_volume: %.1f dB\n", -logdb(power));
max_volume = 0x8000;
while (max_volume > 0 && !vd->histogram[0x8000 + max_volume] &&
!vd->histogram[0x8000 - max_volume])
max_volume--;
av_log(ctx, AV_LOG_INFO, "max_volume: %.1f dB\n", -logdb(max_volume * max_volume));
for (i = 0; i < 0x10000; i++)
histdb[(int)logdb((i - 0x8000) * (i - 0x8000))] += vd->histogram[i];
for (i = 0; i <= MAX_DB && !histdb[i]; i++);
for (; i <= MAX_DB && sum < nb_samples / 1000; i++) {
av_log(ctx, AV_LOG_INFO, "histogram_%ddb: %"PRId64"\n", i, histdb[i]);
sum += histdb[i];
}
}
static void uninit(AVFilterContext *ctx)
{
print_stats(ctx);
}
static const AVFilterPad volumedetect_inputs[] = {
{
.name = "default",
.type = AVMEDIA_TYPE_AUDIO,
.get_audio_buffer = ff_null_get_audio_buffer,
.filter_frame = filter_frame,
},
{ NULL }
};
static const AVFilterPad volumedetect_outputs[] = {
{
.name = "default",
.type = AVMEDIA_TYPE_AUDIO,
},
{ NULL }
};
AVFilter avfilter_af_volumedetect = {
.name = "volumedetect",
.description = NULL_IF_CONFIG_SMALL("Detect audio volume."),
.priv_size = sizeof(VolDetectContext),
.query_formats = query_formats,
.uninit = uninit,
.inputs = volumedetect_inputs,
.outputs = volumedetect_outputs,
};
|
