aboutsummaryrefslogtreecommitdiffstats
path: root/libavfilter/af_silencedetect.c
blob: 6518283d9f48a39ce6769ac4eaf9cd45eb839b7a (plain) (blame)
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
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
/*
 * Copyright (c) 2012 Clément Bœsch <u pkh me>
 *
 * 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
 */

/**
 * @file
 * Audio silence detector
 */

#include <float.h> /* DBL_MAX */

#include "libavutil/opt.h"
#include "libavutil/timestamp.h"
#include "audio.h"
#include "formats.h"
#include "avfilter.h"
#include "internal.h"

typedef struct SilenceDetectContext {
    const AVClass *class;
    double noise;               ///< noise amplitude ratio
    int64_t duration;           ///< minimum duration of silence until notification
    int mono;                   ///< mono mode : check each channel separately (default = check when ALL channels are silent)
    int channels;               ///< number of channels
    int independent_channels;   ///< number of entries in following arrays (always 1 in mono mode)
    int64_t *nb_null_samples;   ///< (array) current number of continuous zero samples
    int64_t *start;             ///< (array) if silence is detected, this value contains the time of the first zero sample (default/unset = INT64_MIN)
    int64_t frame_end;          ///< pts of the end of the current frame (used to compute duration of silence at EOS)
    int last_sample_rate;       ///< last sample rate to check for sample rate changes
    AVRational time_base;       ///< time_base

    void (*silencedetect)(struct SilenceDetectContext *s, AVFrame *insamples,
                          int nb_samples, int64_t nb_samples_notify,
                          AVRational time_base);
} SilenceDetectContext;

#define MAX_DURATION (24*3600*1000000LL)
#define OFFSET(x) offsetof(SilenceDetectContext, x)
#define FLAGS AV_OPT_FLAG_FILTERING_PARAM|AV_OPT_FLAG_AUDIO_PARAM
static const AVOption silencedetect_options[] = {
    { "n",         "set noise tolerance",              OFFSET(noise),     AV_OPT_TYPE_DOUBLE, {.dbl=0.001},          0, DBL_MAX,  FLAGS },
    { "noise",     "set noise tolerance",              OFFSET(noise),     AV_OPT_TYPE_DOUBLE, {.dbl=0.001},          0, DBL_MAX,  FLAGS },
    { "d",         "set minimum duration in seconds",  OFFSET(duration),  AV_OPT_TYPE_DURATION, {.i64=2000000},      0, MAX_DURATION,FLAGS },
    { "duration",  "set minimum duration in seconds",  OFFSET(duration),  AV_OPT_TYPE_DURATION, {.i64=2000000},      0, MAX_DURATION,FLAGS },
    { "mono",      "check each channel separately",    OFFSET(mono),      AV_OPT_TYPE_BOOL,   {.i64=0},              0, 1,        FLAGS },
    { "m",         "check each channel separately",    OFFSET(mono),      AV_OPT_TYPE_BOOL,   {.i64=0},              0, 1,        FLAGS },
    { NULL }
};

AVFILTER_DEFINE_CLASS(silencedetect);

static void set_meta(AVFrame *insamples, int channel, const char *key, char *value)
{
    char key2[128];

    if (channel)
        snprintf(key2, sizeof(key2), "lavfi.%s.%d", key, channel);
    else
        snprintf(key2, sizeof(key2), "lavfi.%s", key);
    av_dict_set(&insamples->metadata, key2, value, 0);
}
static av_always_inline void update(SilenceDetectContext *s, AVFrame *insamples,
                                    int is_silence, int current_sample, int64_t nb_samples_notify,
                                    AVRational time_base)
{
    int channel = current_sample % s->independent_channels;
    if (is_silence) {
        if (s->start[channel] == INT64_MIN) {
            s->nb_null_samples[channel]++;
            if (s->nb_null_samples[channel] >= nb_samples_notify) {
                s->start[channel] = insamples->pts + av_rescale_q(current_sample / s->channels + 1 - nb_samples_notify * s->independent_channels / s->channels,
                        (AVRational){ 1, s->last_sample_rate }, time_base);
                set_meta(insamples, s->mono ? channel + 1 : 0, "silence_start",
                        av_ts2timestr(s->start[channel], &time_base));
                if (s->mono)
                    av_log(s, AV_LOG_INFO, "channel: %d | ", channel);
                av_log(s, AV_LOG_INFO, "silence_start: %s\n",
                        av_ts2timestr(s->start[channel], &time_base));
            }
        }
    } else {
        if (s->start[channel] > INT64_MIN) {
            int64_t end_pts = insamples ? insamples->pts + av_rescale_q(current_sample / s->channels,
                    (AVRational){ 1, s->last_sample_rate }, time_base)
                    : s->frame_end;
            int64_t duration_ts = end_pts - s->start[channel];
            if (insamples) {
                set_meta(insamples, s->mono ? channel + 1 : 0, "silence_end",
                        av_ts2timestr(end_pts, &time_base));
                set_meta(insamples, s->mono ? channel + 1 : 0, "silence_duration",
                        av_ts2timestr(duration_ts, &time_base));
            }
            if (s->mono)
                av_log(s, AV_LOG_INFO, "channel: %d | ", channel);
            av_log(s, AV_LOG_INFO, "silence_end: %s | silence_duration: %s\n",
                    av_ts2timestr(end_pts, &time_base),
                    av_ts2timestr(duration_ts, &time_base));
        }
        s->nb_null_samples[channel] = 0;
        s->start[channel] = INT64_MIN;
    }
}

#define SILENCE_DETECT(name, type)                                               \
static void silencedetect_##name(SilenceDetectContext *s, AVFrame *insamples,    \
                                 int nb_samples, int64_t nb_samples_notify,      \
                                 AVRational time_base)                           \
{                                                                                \
    const type *p = (const type *)insamples->data[0];                            \
    const type noise = s->noise;                                                 \
    int i;                                                                       \
                                                                                 \
    for (i = 0; i < nb_samples; i++, p++)                                        \
        update(s, insamples, *p < noise && *p > -noise, i,                       \
               nb_samples_notify, time_base);                                    \
}

#define SILENCE_DETECT_PLANAR(name, type)                                        \
static void silencedetect_##name(SilenceDetectContext *s, AVFrame *insamples,    \
                                 int nb_samples, int64_t nb_samples_notify,      \
                                 AVRational time_base)                           \
{                                                                                \
    const int channels = insamples->ch_layout.nb_channels;                       \
    const type noise = s->noise;                                                 \
                                                                                 \
    nb_samples /= channels;                                                      \
    for (int i = 0; i < nb_samples; i++) {                                       \
        for (int ch = 0; ch < insamples->ch_layout.nb_channels; ch++) {          \
            const type *p = (const type *)insamples->extended_data[ch];          \
            update(s, insamples, p[i] < noise && p[i] > -noise,                  \
                   channels * i + ch,                                            \
                   nb_samples_notify, time_base);                                \
        }                                                                        \
    }                                                                            \
}

SILENCE_DETECT(dbl, double)
SILENCE_DETECT(flt, float)
SILENCE_DETECT(s32, int32_t)
SILENCE_DETECT(s16, int16_t)

SILENCE_DETECT_PLANAR(dblp, double)
SILENCE_DETECT_PLANAR(fltp, float)
SILENCE_DETECT_PLANAR(s32p, int32_t)
SILENCE_DETECT_PLANAR(s16p, int16_t)

static int config_input(AVFilterLink *inlink)
{
    AVFilterContext *ctx = inlink->dst;
    SilenceDetectContext *s = ctx->priv;
    int c;

    s->channels = inlink->ch_layout.nb_channels;
    s->duration = av_rescale(s->duration, inlink->sample_rate, AV_TIME_BASE);
    s->independent_channels = s->mono ? s->channels : 1;
    s->nb_null_samples = av_calloc(s->independent_channels,
                                   sizeof(*s->nb_null_samples));
    if (!s->nb_null_samples)
        return AVERROR(ENOMEM);
    s->start = av_malloc_array(sizeof(*s->start), s->independent_channels);
    if (!s->start)
        return AVERROR(ENOMEM);
    for (c = 0; c < s->independent_channels; c++)
        s->start[c] = INT64_MIN;

    switch (inlink->format) {
    case AV_SAMPLE_FMT_DBL: s->silencedetect = silencedetect_dbl; break;
    case AV_SAMPLE_FMT_FLT: s->silencedetect = silencedetect_flt; break;
    case AV_SAMPLE_FMT_S32:
        s->noise *= INT32_MAX;
        s->silencedetect = silencedetect_s32;
        break;
    case AV_SAMPLE_FMT_S16:
        s->noise *= INT16_MAX;
        s->silencedetect = silencedetect_s16;
        break;
    case AV_SAMPLE_FMT_DBLP: s->silencedetect = silencedetect_dblp; break;
    case AV_SAMPLE_FMT_FLTP: s->silencedetect = silencedetect_fltp; break;
    case AV_SAMPLE_FMT_S32P:
        s->noise *= INT32_MAX;
        s->silencedetect = silencedetect_s32p;
        break;
    case AV_SAMPLE_FMT_S16P:
        s->noise *= INT16_MAX;
        s->silencedetect = silencedetect_s16p;
        break;
    default:
        return AVERROR_BUG;
    }

    return 0;
}

static int filter_frame(AVFilterLink *inlink, AVFrame *insamples)
{
    SilenceDetectContext *s         = inlink->dst->priv;
    const int nb_channels           = inlink->ch_layout.nb_channels;
    const int srate                 = inlink->sample_rate;
    const int nb_samples            = insamples->nb_samples     * nb_channels;
    const int64_t nb_samples_notify = s->duration * (s->mono ? 1 : nb_channels);
    int c;

    // scale number of null samples to the new sample rate
    if (s->last_sample_rate && s->last_sample_rate != srate)
        for (c = 0; c < s->independent_channels; c++) {
            s->nb_null_samples[c] = srate * s->nb_null_samples[c] / s->last_sample_rate;
        }
    s->last_sample_rate = srate;
    s->time_base = inlink->time_base;
    s->frame_end = insamples->pts + av_rescale_q(insamples->nb_samples,
            (AVRational){ 1, s->last_sample_rate }, inlink->time_base);

    s->silencedetect(s, insamples, nb_samples, nb_samples_notify,
                     inlink->time_base);

    return ff_filter_frame(inlink->dst->outputs[0], insamples);
}

static av_cold void uninit(AVFilterContext *ctx)
{
    SilenceDetectContext *s = ctx->priv;
    int c;

    for (c = 0; c < s->independent_channels; c++)
        if (s->start[c] > INT64_MIN)
            update(s, NULL, 0, c, 0, s->time_base);
    av_freep(&s->nb_null_samples);
    av_freep(&s->start);
}

static const AVFilterPad silencedetect_inputs[] = {
    {
        .name         = "default",
        .type         = AVMEDIA_TYPE_AUDIO,
        .config_props = config_input,
        .filter_frame = filter_frame,
    },
};

static const AVFilterPad silencedetect_outputs[] = {
    {
        .name = "default",
        .type = AVMEDIA_TYPE_AUDIO,
    },
};

const AVFilter ff_af_silencedetect = {
    .name          = "silencedetect",
    .description   = NULL_IF_CONFIG_SMALL("Detect silence."),
    .priv_size     = sizeof(SilenceDetectContext),
    .uninit        = uninit,
    FILTER_INPUTS(silencedetect_inputs),
    FILTER_OUTPUTS(silencedetect_outputs),
    FILTER_SAMPLEFMTS(AV_SAMPLE_FMT_DBL, AV_SAMPLE_FMT_DBLP,
                      AV_SAMPLE_FMT_FLT, AV_SAMPLE_FMT_FLTP,
                      AV_SAMPLE_FMT_S32, AV_SAMPLE_FMT_S32P,
                      AV_SAMPLE_FMT_S16, AV_SAMPLE_FMT_S16P),
    .priv_class    = &silencedetect_class,
    .flags         = AVFILTER_FLAG_METADATA_ONLY,
};