lavfi: add audio silencedetect filter.
This commit is contained in:
Clément Bœsch
parent
5ccdb907c1
commit
0c01947316
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@ -20,6 +20,7 @@ version next:
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- v308 Quicktime Uncompressed 4:4:4 encoder and decoder
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- yuv4 libquicktime packed 4:2:0 encoder and decoder
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- ffprobe -show_frames option
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- silencedetect audio filter
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version 0.9:
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@ -358,6 +358,36 @@ Note that @command{ffmpeg} integrates a default down-mix (and up-mix) system
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that should be preferred (see "-ac" option) unless you have very specific
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needs.
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@section silencedetect
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Detect silence in an audio stream.
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This filter logs a message when it detects that the input audio volume is less
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or equal to a noise tolerance value for a duration greater or equal to the
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minimum detected noise duration.
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The printed times and duration are expressed in seconds.
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@table @option
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@item duration, d
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Set silence duration until notification (default is 2 seconds).
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@item noise, n
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Set noise tolerance. Can be specified in dB (in case "dB" is appended to the
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specified value) or amplitude ratio. Default is -60dB, or 0.001.
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@end table
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Detect 5 seconds of silence with -50dB noise tolerance:
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@example
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silencedetect=n=-50dB:d=5
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@end example
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Complete example with @command{ffmpeg} to detect silence with 0.0001 noise
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tolerance in @file{silence.mp3}:
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@example
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ffmpeg -f lavfi -i amovie=silence.mp3,silencedetect=noise=0.0001 -f null -
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@end example
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@section volume
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Adjust the input audio volume.
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@ -34,6 +34,7 @@ OBJS-$(CONFIG_ASPLIT_FILTER) += af_asplit.o
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OBJS-$(CONFIG_ASTREAMSYNC_FILTER) += af_astreamsync.o
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OBJS-$(CONFIG_EARWAX_FILTER) += af_earwax.o
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OBJS-$(CONFIG_PAN_FILTER) += af_pan.o
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OBJS-$(CONFIG_SILENCEDETECT_FILTER) += af_silencedetect.o
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OBJS-$(CONFIG_VOLUME_FILTER) += af_volume.o
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OBJS-$(CONFIG_ABUFFER_FILTER) += asrc_abuffer.o
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@ -0,0 +1,175 @@
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/*
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* Copyright (c) 2012 Clément Bœsch <ubitux@gmail.com>
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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 "libavutil/opt.h"
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#include "avfilter.h"
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typedef struct {
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const AVClass *class;
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char *noise_str; ///< noise option string
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double noise; ///< noise amplitude ratio
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int 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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double 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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} SilenceDetectContext;
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#define OFFSET(x) offsetof(SilenceDetectContext, x)
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static const AVOption silencedetect_options[] = {
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{ "n", "set noise tolerance", OFFSET(noise_str), AV_OPT_TYPE_STRING, {.str="-60dB"}, CHAR_MIN, CHAR_MAX },
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{ "noise", "set noise tolerance", OFFSET(noise_str), AV_OPT_TYPE_STRING, {.str="-60dB"}, CHAR_MIN, CHAR_MAX },
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{ "d", "set minimum duration in seconds", OFFSET(duration), AV_OPT_TYPE_INT, {.dbl=2}, 0, INT_MAX},
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{ "duration", "set minimum duration in seconds", OFFSET(duration), AV_OPT_TYPE_INT, {.dbl=2}, 0, INT_MAX},
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{ NULL },
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};
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static const char *silencedetect_get_name(void *ctx)
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{
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return "silencedetect";
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}
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static const AVClass silencedetect_class = {
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.class_name = "SilenceDetectContext",
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.item_name = silencedetect_get_name,
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.option = silencedetect_options,
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};
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static av_cold int init(AVFilterContext *ctx, const char *args, void *opaque)
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{
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int ret;
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char *tail;
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SilenceDetectContext *silence = ctx->priv;
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silence->class = &silencedetect_class;
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av_opt_set_defaults(silence);
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if ((ret = av_set_options_string(silence, args, "=", ":")) < 0) {
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av_log(ctx, AV_LOG_ERROR, "Error parsing options string: '%s'\n", args);
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return ret;
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}
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silence->noise = strtod(silence->noise_str, &tail);
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if (!strcmp(tail, "dB")) {
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silence->noise = pow(10, silence->noise/20);
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} else if (*tail) {
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av_log(ctx, AV_LOG_ERROR, "Invalid value '%s' for noise parameter.\n",
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silence->noise_str);
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return AVERROR(EINVAL);
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}
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return 0;
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}
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static void filter_samples(AVFilterLink *inlink, AVFilterBufferRef *insamples)
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{
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int i;
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SilenceDetectContext *silence = inlink->dst->priv;
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const int nb_channels = av_get_channel_layout_nb_channels(inlink->channel_layout);
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const int srate = inlink->sample_rate;
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const int nb_samples = insamples->audio->nb_samples * nb_channels;
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const int64_t nb_samples_notify = srate * silence->duration * nb_channels;
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// scale number of null samples to the new sample rate
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if (silence->last_sample_rate && silence->last_sample_rate != srate)
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silence->nb_null_samples =
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srate * silence->nb_null_samples / silence->last_sample_rate;
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silence->last_sample_rate = srate;
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// TODO: support more sample formats
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if (insamples->format == AV_SAMPLE_FMT_DBL) {
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double *p = (double *)insamples->data[0];
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for (i = 0; i < nb_samples; i++, p++) {
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if (*p < silence->noise && *p > -silence->noise) {
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if (!silence->start) {
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silence->nb_null_samples++;
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if (silence->nb_null_samples >= nb_samples_notify) {
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silence->start = insamples->pts * av_q2d(inlink->time_base) - silence->duration;
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av_log(silence, AV_LOG_INFO,
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"silence_start: %f\n", silence->start);
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}
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}
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} else {
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if (silence->start) {
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double end = insamples->pts * av_q2d(inlink->time_base);
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av_log(silence, AV_LOG_INFO,
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"silence_end: %f | silence_duration: %f\n",
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end, end - silence->start);
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}
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silence->nb_null_samples = silence->start = 0;
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}
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}
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}
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avfilter_filter_samples(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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enum AVSampleFormat sample_fmts[] = {
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AV_SAMPLE_FMT_DBL,
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AV_SAMPLE_FMT_NONE
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};
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int packing_fmts[] = { AVFILTER_PACKED, -1 };
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formats = avfilter_make_all_channel_layouts();
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if (!formats)
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return AVERROR(ENOMEM);
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avfilter_set_common_channel_layouts(ctx, formats);
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formats = avfilter_make_format_list(sample_fmts);
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if (!formats)
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return AVERROR(ENOMEM);
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avfilter_set_common_sample_formats(ctx, formats);
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formats = avfilter_make_format_list(packing_fmts);
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if (!formats)
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return AVERROR(ENOMEM);
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avfilter_set_common_packing_formats(ctx, formats);
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return 0;
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}
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AVFilter avfilter_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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.init = init,
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.query_formats = query_formats,
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.inputs = (const AVFilterPad[]) {
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{ .name = "default",
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.type = AVMEDIA_TYPE_AUDIO,
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.get_audio_buffer = avfilter_null_get_audio_buffer,
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.filter_samples = filter_samples, },
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{ .name = NULL }
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},
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.outputs = (const AVFilterPad[]) {
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{ .name = "default",
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.type = AVMEDIA_TYPE_AUDIO, },
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{ .name = NULL }
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},
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};
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@ -44,6 +44,7 @@ void avfilter_register_all(void)
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REGISTER_FILTER (ASTREAMSYNC, astreamsync, af);
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REGISTER_FILTER (EARWAX, earwax, af);
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REGISTER_FILTER (PAN, pan, af);
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REGISTER_FILTER (SILENCEDETECT, silencedetect, af);
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REGISTER_FILTER (VOLUME, volume, af);
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REGISTER_FILTER (ABUFFER, abuffer, asrc);
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@ -30,8 +30,8 @@
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#include "libavcodec/avcodec.h"
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#define LIBAVFILTER_VERSION_MAJOR 2
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#define LIBAVFILTER_VERSION_MINOR 57
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#define LIBAVFILTER_VERSION_MICRO 101
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#define LIBAVFILTER_VERSION_MINOR 58
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#define LIBAVFILTER_VERSION_MICRO 100
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#define LIBAVFILTER_VERSION_INT AV_VERSION_INT(LIBAVFILTER_VERSION_MAJOR, \
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LIBAVFILTER_VERSION_MINOR, \
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