diff options
Diffstat (limited to 'libavfilter/af_silencedetect.c')
| -rw-r--r-- | libavfilter/af_silencedetect.c | 215 |
1 files changed, 215 insertions, 0 deletions
diff --git a/libavfilter/af_silencedetect.c b/libavfilter/af_silencedetect.c new file mode 100644 index 0000000000..b048d63738 --- /dev/null +++ b/libavfilter/af_silencedetect.c @@ -0,0 +1,215 @@ +/* + * 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 + double duration; ///< minimum duration of silence until notification + int64_t nb_null_samples; ///< current number of continuous zero samples + int64_t start; ///< if silence is detected, this value contains the time of the first zero sample + int last_sample_rate; ///< last sample rate to check for sample rate changes + + void (*silencedetect)(struct SilenceDetectContext *s, AVFrame *insamples, + int nb_samples, int64_t nb_samples_notify, + AVRational time_base); +} SilenceDetectContext; + +#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_DOUBLE, {.dbl=2.}, 0, 24*60*60, FLAGS }, + { "duration", "set minimum duration in seconds", OFFSET(duration), AV_OPT_TYPE_DOUBLE, {.dbl=2.}, 0, 24*60*60, FLAGS }, + { NULL } +}; + +AVFILTER_DEFINE_CLASS(silencedetect); + +static char *get_metadata_val(AVFrame *insamples, const char *key) +{ + AVDictionaryEntry *e = av_dict_get(insamples->metadata, key, NULL, 0); + return e && e->value ? e->value : NULL; +} + +static av_always_inline void update(SilenceDetectContext *s, AVFrame *insamples, + int is_silence, int64_t nb_samples_notify, + AVRational time_base) +{ + if (is_silence) { + if (!s->start) { + s->nb_null_samples++; + if (s->nb_null_samples >= nb_samples_notify) { + s->start = insamples->pts - (int64_t)(s->duration / av_q2d(time_base) + .5); + av_dict_set(&insamples->metadata, "lavfi.silence_start", + av_ts2timestr(s->start, &time_base), 0); + av_log(s, AV_LOG_INFO, "silence_start: %s\n", + get_metadata_val(insamples, "lavfi.silence_start")); + } + } + } else { + if (s->start) { + av_dict_set(&insamples->metadata, "lavfi.silence_end", + av_ts2timestr(insamples->pts, &time_base), 0); + av_dict_set(&insamples->metadata, "lavfi.silence_duration", + av_ts2timestr(insamples->pts - s->start, &time_base), 0); + av_log(s, AV_LOG_INFO, + "silence_end: %s | silence_duration: %s\n", + get_metadata_val(insamples, "lavfi.silence_end"), + get_metadata_val(insamples, "lavfi.silence_duration")); + } + s->nb_null_samples = s->start = 0; + } +} + +#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, \ + nb_samples_notify, time_base); \ +} + +SILENCE_DETECT(dbl, double) +SILENCE_DETECT(flt, float) +SILENCE_DETECT(s32, int32_t) +SILENCE_DETECT(s16, int16_t) + +static int config_input(AVFilterLink *inlink) +{ + AVFilterContext *ctx = inlink->dst; + SilenceDetectContext *s = ctx->priv; + + 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; + } + + return 0; +} + +static int filter_frame(AVFilterLink *inlink, AVFrame *insamples) +{ + SilenceDetectContext *s = inlink->dst->priv; + const int nb_channels = inlink->channels; + const int srate = inlink->sample_rate; + const int nb_samples = insamples->nb_samples * nb_channels; + const int64_t nb_samples_notify = srate * s->duration * nb_channels; + + // scale number of null samples to the new sample rate + if (s->last_sample_rate && s->last_sample_rate != srate) + s->nb_null_samples = srate * s->nb_null_samples / s->last_sample_rate; + s->last_sample_rate = srate; + + // TODO: document metadata + s->silencedetect(s, insamples, nb_samples, nb_samples_notify, + inlink->time_base); + + return ff_filter_frame(inlink->dst->outputs[0], insamples); +} + +static int query_formats(AVFilterContext *ctx) +{ + AVFilterFormats *formats = NULL; + AVFilterChannelLayouts *layouts = NULL; + static const enum AVSampleFormat sample_fmts[] = { + AV_SAMPLE_FMT_DBL, + AV_SAMPLE_FMT_FLT, + AV_SAMPLE_FMT_S32, + AV_SAMPLE_FMT_S16, + AV_SAMPLE_FMT_NONE + }; + int ret; + + layouts = ff_all_channel_layouts(); + if (!layouts) + return AVERROR(ENOMEM); + ret = ff_set_common_channel_layouts(ctx, layouts); + if (ret < 0) + return ret; + + formats = ff_make_format_list(sample_fmts); + if (!formats) + return AVERROR(ENOMEM); + ret = ff_set_common_formats(ctx, formats); + if (ret < 0) + return ret; + + formats = ff_all_samplerates(); + if (!formats) + return AVERROR(ENOMEM); + return ff_set_common_samplerates(ctx, formats); +} + +static const AVFilterPad silencedetect_inputs[] = { + { + .name = "default", + .type = AVMEDIA_TYPE_AUDIO, + .config_props = config_input, + .filter_frame = filter_frame, + }, + { NULL } +}; + +static const AVFilterPad silencedetect_outputs[] = { + { + .name = "default", + .type = AVMEDIA_TYPE_AUDIO, + }, + { NULL } +}; + +AVFilter ff_af_silencedetect = { + .name = "silencedetect", + .description = NULL_IF_CONFIG_SMALL("Detect silence."), + .priv_size = sizeof(SilenceDetectContext), + .query_formats = query_formats, + .inputs = silencedetect_inputs, + .outputs = silencedetect_outputs, + .priv_class = &silencedetect_class, +}; |