216 lines
8.0 KiB
C
216 lines
8.0 KiB
C
/*
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* Copyright (c) 2012 Clément Bœsch <u pkh me>
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*
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* This file is part of FFmpeg.
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*
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* FFmpeg is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* FFmpeg is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with FFmpeg; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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/**
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* @file
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* Audio silence detector
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*/
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#include <float.h> /* DBL_MAX */
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#include "libavutil/opt.h"
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#include "libavutil/timestamp.h"
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#include "audio.h"
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#include "formats.h"
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#include "avfilter.h"
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#include "internal.h"
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typedef struct SilenceDetectContext {
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const AVClass *class;
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double noise; ///< noise amplitude ratio
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double duration; ///< minimum duration of silence until notification
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int64_t nb_null_samples; ///< current number of continuous zero samples
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int64_t start; ///< if silence is detected, this value contains the time of the first zero sample
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int last_sample_rate; ///< last sample rate to check for sample rate changes
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void (*silencedetect)(struct SilenceDetectContext *s, AVFrame *insamples,
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int nb_samples, int64_t nb_samples_notify,
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AVRational time_base);
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} SilenceDetectContext;
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#define OFFSET(x) offsetof(SilenceDetectContext, x)
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#define FLAGS AV_OPT_FLAG_FILTERING_PARAM|AV_OPT_FLAG_AUDIO_PARAM
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static const AVOption silencedetect_options[] = {
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{ "n", "set noise tolerance", OFFSET(noise), AV_OPT_TYPE_DOUBLE, {.dbl=0.001}, 0, DBL_MAX, FLAGS },
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{ "noise", "set noise tolerance", OFFSET(noise), AV_OPT_TYPE_DOUBLE, {.dbl=0.001}, 0, DBL_MAX, FLAGS },
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{ "d", "set minimum duration in seconds", OFFSET(duration), AV_OPT_TYPE_DOUBLE, {.dbl=2.}, 0, 24*60*60, FLAGS },
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{ "duration", "set minimum duration in seconds", OFFSET(duration), AV_OPT_TYPE_DOUBLE, {.dbl=2.}, 0, 24*60*60, FLAGS },
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{ NULL }
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};
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AVFILTER_DEFINE_CLASS(silencedetect);
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static char *get_metadata_val(AVFrame *insamples, const char *key)
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{
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AVDictionaryEntry *e = av_dict_get(insamples->metadata, key, NULL, 0);
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return e && e->value ? e->value : NULL;
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}
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static av_always_inline void update(SilenceDetectContext *s, AVFrame *insamples,
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int is_silence, int64_t nb_samples_notify,
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AVRational time_base)
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{
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if (is_silence) {
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if (!s->start) {
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s->nb_null_samples++;
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if (s->nb_null_samples >= nb_samples_notify) {
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s->start = insamples->pts - (int64_t)(s->duration / av_q2d(time_base) + .5);
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av_dict_set(&insamples->metadata, "lavfi.silence_start",
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av_ts2timestr(s->start, &time_base), 0);
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av_log(s, AV_LOG_INFO, "silence_start: %s\n",
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get_metadata_val(insamples, "lavfi.silence_start"));
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}
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}
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} else {
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if (s->start) {
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av_dict_set(&insamples->metadata, "lavfi.silence_end",
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av_ts2timestr(insamples->pts, &time_base), 0);
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av_dict_set(&insamples->metadata, "lavfi.silence_duration",
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av_ts2timestr(insamples->pts - s->start, &time_base), 0);
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av_log(s, AV_LOG_INFO,
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"silence_end: %s | silence_duration: %s\n",
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get_metadata_val(insamples, "lavfi.silence_end"),
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get_metadata_val(insamples, "lavfi.silence_duration"));
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}
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s->nb_null_samples = s->start = 0;
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}
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}
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#define SILENCE_DETECT(name, type) \
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static void silencedetect_##name(SilenceDetectContext *s, AVFrame *insamples, \
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int nb_samples, int64_t nb_samples_notify, \
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AVRational time_base) \
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{ \
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const type *p = (const type *)insamples->data[0]; \
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const type noise = s->noise; \
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int i; \
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\
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for (i = 0; i < nb_samples; i++, p++) \
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update(s, insamples, *p < noise && *p > -noise, \
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nb_samples_notify, time_base); \
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}
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SILENCE_DETECT(dbl, double)
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SILENCE_DETECT(flt, float)
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SILENCE_DETECT(s32, int32_t)
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SILENCE_DETECT(s16, int16_t)
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static int config_input(AVFilterLink *inlink)
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{
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AVFilterContext *ctx = inlink->dst;
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SilenceDetectContext *s = ctx->priv;
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switch (inlink->format) {
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case AV_SAMPLE_FMT_DBL: s->silencedetect = silencedetect_dbl; break;
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case AV_SAMPLE_FMT_FLT: s->silencedetect = silencedetect_flt; break;
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case AV_SAMPLE_FMT_S32:
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s->noise *= INT32_MAX;
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s->silencedetect = silencedetect_s32;
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break;
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case AV_SAMPLE_FMT_S16:
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s->noise *= INT16_MAX;
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s->silencedetect = silencedetect_s16;
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break;
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}
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return 0;
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}
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static int filter_frame(AVFilterLink *inlink, AVFrame *insamples)
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{
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SilenceDetectContext *s = inlink->dst->priv;
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const int nb_channels = inlink->channels;
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const int srate = inlink->sample_rate;
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const int nb_samples = insamples->nb_samples * nb_channels;
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const int64_t nb_samples_notify = srate * s->duration * nb_channels;
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// scale number of null samples to the new sample rate
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if (s->last_sample_rate && s->last_sample_rate != srate)
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s->nb_null_samples = srate * s->nb_null_samples / s->last_sample_rate;
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s->last_sample_rate = srate;
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// TODO: document metadata
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s->silencedetect(s, insamples, nb_samples, nb_samples_notify,
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inlink->time_base);
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return ff_filter_frame(inlink->dst->outputs[0], insamples);
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}
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static int query_formats(AVFilterContext *ctx)
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{
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AVFilterFormats *formats = NULL;
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AVFilterChannelLayouts *layouts = NULL;
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static const enum AVSampleFormat sample_fmts[] = {
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AV_SAMPLE_FMT_DBL,
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AV_SAMPLE_FMT_FLT,
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AV_SAMPLE_FMT_S32,
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AV_SAMPLE_FMT_S16,
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AV_SAMPLE_FMT_NONE
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};
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int ret;
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layouts = ff_all_channel_layouts();
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if (!layouts)
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return AVERROR(ENOMEM);
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ret = ff_set_common_channel_layouts(ctx, layouts);
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if (ret < 0)
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return ret;
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formats = ff_make_format_list(sample_fmts);
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if (!formats)
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return AVERROR(ENOMEM);
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ret = ff_set_common_formats(ctx, formats);
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if (ret < 0)
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return ret;
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formats = ff_all_samplerates();
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if (!formats)
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return AVERROR(ENOMEM);
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return ff_set_common_samplerates(ctx, formats);
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}
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static const AVFilterPad silencedetect_inputs[] = {
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{
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.name = "default",
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.type = AVMEDIA_TYPE_AUDIO,
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.config_props = config_input,
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.filter_frame = filter_frame,
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},
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{ NULL }
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};
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static const AVFilterPad silencedetect_outputs[] = {
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{
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.name = "default",
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.type = AVMEDIA_TYPE_AUDIO,
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},
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{ NULL }
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};
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AVFilter ff_af_silencedetect = {
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.name = "silencedetect",
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.description = NULL_IF_CONFIG_SMALL("Detect silence."),
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.priv_size = sizeof(SilenceDetectContext),
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.query_formats = query_formats,
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.inputs = silencedetect_inputs,
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.outputs = silencedetect_outputs,
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.priv_class = &silencedetect_class,
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};
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