FFmpeg coverage

Directory: ../../../ffmpeg/
File: src/libavfilter/af_silencedetect.c
Date: 2025-10-29 00:48:36
Exec Total Coverage
Lines: 76 109 69.7%
Functions: 6 13 46.2%
Branches: 35 109 32.1%
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1 /*
2 * Copyright (c) 2012 Clément Bœsch <u pkh me>
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 /**
22 * @file
23 * Audio silence detector
24 */
25
26 #include <float.h> /* DBL_MAX */
27
28 #include "libavutil/mem.h"
29 #include "libavutil/opt.h"
30 #include "libavutil/timestamp.h"
31 #include "audio.h"
32 #include "avfilter.h"
33 #include "filters.h"
34
35 typedef struct SilenceDetectContext {
36 const AVClass *class;
37 double noise; ///< noise amplitude ratio
38 int64_t duration; ///< minimum duration of silence until notification
39 int mono; ///< mono mode : check each channel separately (default = check when ALL channels are silent)
40 int channels; ///< number of channels
41 int independent_channels; ///< number of entries in following arrays (always 1 in mono mode)
42 int64_t *nb_null_samples; ///< (array) current number of continuous zero samples
43 int64_t *start; ///< (array) if silence is detected, this value contains the time of the first zero sample (default/unset = INT64_MIN)
44 int64_t frame_end; ///< pts of the end of the current frame (used to compute duration of silence at EOS)
45 int last_sample_rate; ///< last sample rate to check for sample rate changes
46 AVRational time_base; ///< time_base
47
48 void (*silencedetect)(AVFilterContext *ctx, AVFrame *insamples,
49 int nb_samples, int64_t nb_samples_notify,
50 AVRational time_base);
51 } SilenceDetectContext;
52
53 #define MAX_DURATION (24*3600*1000000LL)
54 #define OFFSET(x) offsetof(SilenceDetectContext, x)
55 #define FLAGS AV_OPT_FLAG_FILTERING_PARAM|AV_OPT_FLAG_AUDIO_PARAM
56 static const AVOption silencedetect_options[] = {
57 { "n", "set noise tolerance", OFFSET(noise), AV_OPT_TYPE_DOUBLE, {.dbl=0.001}, 0, DBL_MAX, FLAGS },
58 { "noise", "set noise tolerance", OFFSET(noise), AV_OPT_TYPE_DOUBLE, {.dbl=0.001}, 0, DBL_MAX, FLAGS },
59 { "d", "set minimum duration in seconds", OFFSET(duration), AV_OPT_TYPE_DURATION, {.i64=2000000}, 0, MAX_DURATION,FLAGS },
60 { "duration", "set minimum duration in seconds", OFFSET(duration), AV_OPT_TYPE_DURATION, {.i64=2000000}, 0, MAX_DURATION,FLAGS },
61 { "mono", "check each channel separately", OFFSET(mono), AV_OPT_TYPE_BOOL, {.i64=0}, 0, 1, FLAGS },
62 { "m", "check each channel separately", OFFSET(mono), AV_OPT_TYPE_BOOL, {.i64=0}, 0, 1, FLAGS },
63 { NULL }
64 };
65
66 AVFILTER_DEFINE_CLASS(silencedetect);
67
68 9 static void set_meta(AVFrame *insamples, int channel, const char *key, char *value)
69 {
70 char key2[128];
71
72
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 9 if (channel)
73 ✗ snprintf(key2, sizeof(key2), "lavfi.%s.%d", key, channel);
74 else
75 9 snprintf(key2, sizeof(key2), "lavfi.%s", key);
76 9 av_dict_set(&insamples->metadata, key2, value, 0);
77 9 }
78 1048554 static av_always_inline void update(AVFilterContext *ctx, AVFrame *insamples,
79 int is_silence, int current_sample, int64_t nb_samples_notify,
80 AVRational time_base)
81 {
82 1048554 SilenceDetectContext *s = ctx->priv;
83 1048554 int channel = current_sample % s->independent_channels;
84
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 1048554 if (is_silence) {
85
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 304774 if (s->start[channel] == INT64_MIN) {
86 221400 s->nb_null_samples[channel]++;
87
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 221400 if (s->nb_null_samples[channel] >= nb_samples_notify) {
88 3 s->start[channel] = insamples->pts + av_rescale_q(current_sample / s->channels + 1 - nb_samples_notify * s->independent_channels / s->channels,
89 3 (AVRational){ 1, s->last_sample_rate }, time_base);
90
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 3 set_meta(insamples, s->mono ? channel + 1 : 0, "silence_start",
91 3 av_ts2timestr(s->start[channel], &time_base));
92
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 3 if (s->mono)
93 ✗ av_log(ctx, AV_LOG_INFO, "channel: %d | ", channel);
94 3 av_log(ctx, AV_LOG_INFO, "silence_start: %s\n",
95 3 av_ts2timestr(s->start[channel], &time_base));
96 }
97 }
98 } else {
99
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 743780 if (s->start[channel] > INT64_MIN) {
100 6 int64_t end_pts = insamples ? insamples->pts + av_rescale_q(current_sample / s->channels,
101 3 (AVRational){ 1, s->last_sample_rate }, time_base)
102
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 3 : s->frame_end;
103 3 int64_t duration_ts = end_pts - s->start[channel];
104
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 3 if (insamples) {
105
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 3 set_meta(insamples, s->mono ? channel + 1 : 0, "silence_end",
106 3 av_ts2timestr(end_pts, &time_base));
107
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 3 set_meta(insamples, s->mono ? channel + 1 : 0, "silence_duration",
108 3 av_ts2timestr(duration_ts, &time_base));
109 }
110
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 3 if (s->mono)
111 ✗ av_log(ctx, AV_LOG_INFO, "channel: %d | ", channel);
112 3 av_log(ctx, AV_LOG_INFO, "silence_end: %s | silence_duration: %s\n",
113 3 av_ts2timestr(end_pts, &time_base),
114 3 av_ts2timestr(duration_ts, &time_base));
115 }
116 743780 s->nb_null_samples[channel] = 0;
117 743780 s->start[channel] = INT64_MIN;
118 }
119 1048554 }
120
121 #define SILENCE_DETECT(name, type) \
122 static void silencedetect_##name(AVFilterContext *ctx, AVFrame *insamples, \
123 int nb_samples, int64_t nb_samples_notify, \
124 AVRational time_base) \
125 { \
126 SilenceDetectContext *s = ctx->priv; \
127 const type *p = (const type *)insamples->data[0]; \
128 const type noise = s->noise; \
129 int i; \
130 \
131 for (i = 0; i < nb_samples; i++, p++) \
132 update(ctx, insamples, *p < noise && *p > -noise, i, \
133 nb_samples_notify, time_base); \
134 }
135
136 #define SILENCE_DETECT_PLANAR(name, type) \
137 static void silencedetect_##name(AVFilterContext *ctx, AVFrame *insamples, \
138 int nb_samples, int64_t nb_samples_notify, \
139 AVRational time_base) \
140 { \
141 SilenceDetectContext *s = ctx->priv; \
142 const int channels = insamples->ch_layout.nb_channels; \
143 const type noise = s->noise; \
144 \
145 nb_samples /= channels; \
146 for (int i = 0; i < nb_samples; i++) { \
147 for (int ch = 0; ch < insamples->ch_layout.nb_channels; ch++) { \
148 const type *p = (const type *)insamples->extended_data[ch]; \
149 update(ctx, insamples, p[i] < noise && p[i] > -noise, \
150 channels * i + ch, \
151 nb_samples_notify, time_base); \
152 } \
153 } \
154 }
155
156 ✗ SILENCE_DETECT(dbl, double)
157 ✗ SILENCE_DETECT(flt, float)
158 ✗ SILENCE_DETECT(s32, int32_t)
159
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 1048566 SILENCE_DETECT(s16, int16_t)
160
161 ✗ SILENCE_DETECT_PLANAR(dblp, double)
162 ✗ SILENCE_DETECT_PLANAR(fltp, float)
163 ✗ SILENCE_DETECT_PLANAR(s32p, int32_t)
164 ✗ SILENCE_DETECT_PLANAR(s16p, int16_t)
165
166 1 static int config_input(AVFilterLink *inlink)
167 {
168 1 AVFilterContext *ctx = inlink->dst;
169 1 SilenceDetectContext *s = ctx->priv;
170 int c;
171
172 1 s->channels = inlink->ch_layout.nb_channels;
173 1 s->duration = av_rescale(s->duration, inlink->sample_rate, AV_TIME_BASE);
174
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 1 s->independent_channels = s->mono ? s->channels : 1;
175 1 s->nb_null_samples = av_calloc(s->independent_channels,
176 sizeof(*s->nb_null_samples));
177
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 1 if (!s->nb_null_samples)
178 ✗ return AVERROR(ENOMEM);
179 1 s->start = av_malloc_array(s->independent_channels, sizeof(*s->start));
180
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 1 if (!s->start)
181 ✗ return AVERROR(ENOMEM);
182
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 2 for (c = 0; c < s->independent_channels; c++)
183 1 s->start[c] = INT64_MIN;
184
185
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 1 switch (inlink->format) {
186 ✗ case AV_SAMPLE_FMT_DBL: s->silencedetect = silencedetect_dbl; break;
187 ✗ case AV_SAMPLE_FMT_FLT: s->silencedetect = silencedetect_flt; break;
188 ✗ case AV_SAMPLE_FMT_S32:
189 ✗ s->noise *= INT32_MAX;
190 ✗ s->silencedetect = silencedetect_s32;
191 ✗ break;
192 1 case AV_SAMPLE_FMT_S16:
193 1 s->noise *= INT16_MAX;
194 1 s->silencedetect = silencedetect_s16;
195 1 break;
196 ✗ case AV_SAMPLE_FMT_DBLP: s->silencedetect = silencedetect_dblp; break;
197 ✗ case AV_SAMPLE_FMT_FLTP: s->silencedetect = silencedetect_fltp; break;
198 ✗ case AV_SAMPLE_FMT_S32P:
199 ✗ s->noise *= INT32_MAX;
200 ✗ s->silencedetect = silencedetect_s32p;
201 ✗ break;
202 ✗ case AV_SAMPLE_FMT_S16P:
203 ✗ s->noise *= INT16_MAX;
204 ✗ s->silencedetect = silencedetect_s16p;
205 ✗ break;
206 ✗ default:
207 ✗ return AVERROR_BUG;
208 }
209
210 1 return 0;
211 }
212
213 12 static int filter_frame(AVFilterLink *inlink, AVFrame *insamples)
214 {
215 12 AVFilterContext *ctx = inlink->dst;
216 12 SilenceDetectContext *s = ctx->priv;
217 12 const int nb_channels = inlink->ch_layout.nb_channels;
218 12 const int srate = inlink->sample_rate;
219 12 const int nb_samples = insamples->nb_samples * nb_channels;
220
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 12 const int64_t nb_samples_notify = s->duration * (s->mono ? 1 : nb_channels);
221 int c;
222
223 // scale number of null samples to the new sample rate
224
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 12 if (s->last_sample_rate && s->last_sample_rate != srate)
225 ✗ for (c = 0; c < s->independent_channels; c++) {
226 ✗ s->nb_null_samples[c] = srate * s->nb_null_samples[c] / s->last_sample_rate;
227 }
228 12 s->last_sample_rate = srate;
229 12 s->time_base = inlink->time_base;
230 12 s->frame_end = insamples->pts + av_rescale_q(insamples->nb_samples,
231 12 (AVRational){ 1, s->last_sample_rate }, inlink->time_base);
232
233 12 s->silencedetect(ctx, insamples, nb_samples, nb_samples_notify,
234 inlink->time_base);
235
236 12 return ff_filter_frame(inlink->dst->outputs[0], insamples);
237 }
238
239 1 static av_cold void uninit(AVFilterContext *ctx)
240 {
241 1 SilenceDetectContext *s = ctx->priv;
242 int c;
243
244
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245
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 1 if (s->start[c] > INT64_MIN)
246 ✗ update(ctx, NULL, 0, c, 0, s->time_base);
247 1 av_freep(&s->nb_null_samples);
248 1 av_freep(&s->start);
249 1 }
250
251 static const AVFilterPad silencedetect_inputs[] = {
252 {
253 .name = "default",
254 .type = AVMEDIA_TYPE_AUDIO,
255 .config_props = config_input,
256 .filter_frame = filter_frame,
257 },
258 };
259
260 const FFFilter ff_af_silencedetect = {
261 .p.name = "silencedetect",
262 .p.description = NULL_IF_CONFIG_SMALL("Detect silence."),
263 .p.priv_class = &silencedetect_class,
264 .p.flags = AVFILTER_FLAG_METADATA_ONLY,
265 .priv_size = sizeof(SilenceDetectContext),
266 .uninit = uninit,
267 FILTER_INPUTS(silencedetect_inputs),
268 FILTER_OUTPUTS(ff_audio_default_filterpad),
269 FILTER_SAMPLEFMTS(AV_SAMPLE_FMT_DBL, AV_SAMPLE_FMT_DBLP,
270 AV_SAMPLE_FMT_FLT, AV_SAMPLE_FMT_FLTP,
271 AV_SAMPLE_FMT_S32, AV_SAMPLE_FMT_S32P,
272 AV_SAMPLE_FMT_S16, AV_SAMPLE_FMT_S16P),
273 };
274