mirror of https://github.com/FFmpeg/FFmpeg.git
Clément Bœsch
13 years ago
parent
5ccdb907c1
commit
0c01947316
6 changed files with 210 additions and 2 deletions
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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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