| 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/opt.h" |
| 29 | #include "libavutil/timestamp.h" |
| 30 | #include "audio.h" |
| 31 | #include "formats.h" |
| 32 | #include "avfilter.h" |
| 33 | #include "internal.h" |
| 34 | |
| 35 | typedef struct SilenceDetectContext { |
| 36 | const AVClass *class; |
| 37 | double noise; ///< noise amplitude ratio |
| 38 | double duration; ///< minimum duration of silence until notification |
| 39 | int64_t nb_null_samples; ///< current number of continuous zero samples |
| 40 | int64_t start; ///< if silence is detected, this value contains the time of the first zero sample |
| 41 | int last_sample_rate; ///< last sample rate to check for sample rate changes |
| 42 | |
| 43 | void (*silencedetect)(struct SilenceDetectContext *s, AVFrame *insamples, |
| 44 | int nb_samples, int64_t nb_samples_notify, |
| 45 | AVRational time_base); |
| 46 | } SilenceDetectContext; |
| 47 | |
| 48 | #define OFFSET(x) offsetof(SilenceDetectContext, x) |
| 49 | #define FLAGS AV_OPT_FLAG_FILTERING_PARAM|AV_OPT_FLAG_AUDIO_PARAM |
| 50 | static const AVOption silencedetect_options[] = { |
| 51 | { "n", "set noise tolerance", OFFSET(noise), AV_OPT_TYPE_DOUBLE, {.dbl=0.001}, 0, DBL_MAX, FLAGS }, |
| 52 | { "noise", "set noise tolerance", OFFSET(noise), AV_OPT_TYPE_DOUBLE, {.dbl=0.001}, 0, DBL_MAX, FLAGS }, |
| 53 | { "d", "set minimum duration in seconds", OFFSET(duration), AV_OPT_TYPE_DOUBLE, {.dbl=2.}, 0, 24*60*60, FLAGS }, |
| 54 | { "duration", "set minimum duration in seconds", OFFSET(duration), AV_OPT_TYPE_DOUBLE, {.dbl=2.}, 0, 24*60*60, FLAGS }, |
| 55 | { NULL } |
| 56 | }; |
| 57 | |
| 58 | AVFILTER_DEFINE_CLASS(silencedetect); |
| 59 | |
| 60 | static char *get_metadata_val(AVFrame *insamples, const char *key) |
| 61 | { |
| 62 | AVDictionaryEntry *e = av_dict_get(insamples->metadata, key, NULL, 0); |
| 63 | return e && e->value ? e->value : NULL; |
| 64 | } |
| 65 | |
| 66 | static av_always_inline void update(SilenceDetectContext *s, AVFrame *insamples, |
| 67 | int is_silence, int64_t nb_samples_notify, |
| 68 | AVRational time_base) |
| 69 | { |
| 70 | if (is_silence) { |
| 71 | if (!s->start) { |
| 72 | s->nb_null_samples++; |
| 73 | if (s->nb_null_samples >= nb_samples_notify) { |
| 74 | s->start = insamples->pts - (int64_t)(s->duration / av_q2d(time_base) + .5); |
| 75 | av_dict_set(&insamples->metadata, "lavfi.silence_start", |
| 76 | av_ts2timestr(s->start, &time_base), 0); |
| 77 | av_log(s, AV_LOG_INFO, "silence_start: %s\n", |
| 78 | get_metadata_val(insamples, "lavfi.silence_start")); |
| 79 | } |
| 80 | } |
| 81 | } else { |
| 82 | if (s->start) { |
| 83 | av_dict_set(&insamples->metadata, "lavfi.silence_end", |
| 84 | av_ts2timestr(insamples->pts, &time_base), 0); |
| 85 | av_dict_set(&insamples->metadata, "lavfi.silence_duration", |
| 86 | av_ts2timestr(insamples->pts - s->start, &time_base), 0); |
| 87 | av_log(s, AV_LOG_INFO, |
| 88 | "silence_end: %s | silence_duration: %s\n", |
| 89 | get_metadata_val(insamples, "lavfi.silence_end"), |
| 90 | get_metadata_val(insamples, "lavfi.silence_duration")); |
| 91 | } |
| 92 | s->nb_null_samples = s->start = 0; |
| 93 | } |
| 94 | } |
| 95 | |
| 96 | #define SILENCE_DETECT(name, type) \ |
| 97 | static void silencedetect_##name(SilenceDetectContext *s, AVFrame *insamples, \ |
| 98 | int nb_samples, int64_t nb_samples_notify, \ |
| 99 | AVRational time_base) \ |
| 100 | { \ |
| 101 | const type *p = (const type *)insamples->data[0]; \ |
| 102 | const type noise = s->noise; \ |
| 103 | int i; \ |
| 104 | \ |
| 105 | for (i = 0; i < nb_samples; i++, p++) \ |
| 106 | update(s, insamples, *p < noise && *p > -noise, \ |
| 107 | nb_samples_notify, time_base); \ |
| 108 | } |
| 109 | |
| 110 | SILENCE_DETECT(dbl, double) |
| 111 | SILENCE_DETECT(flt, float) |
| 112 | SILENCE_DETECT(s32, int32_t) |
| 113 | SILENCE_DETECT(s16, int16_t) |
| 114 | |
| 115 | static int config_input(AVFilterLink *inlink) |
| 116 | { |
| 117 | AVFilterContext *ctx = inlink->dst; |
| 118 | SilenceDetectContext *s = ctx->priv; |
| 119 | |
| 120 | switch (inlink->format) { |
| 121 | case AV_SAMPLE_FMT_DBL: s->silencedetect = silencedetect_dbl; break; |
| 122 | case AV_SAMPLE_FMT_FLT: s->silencedetect = silencedetect_flt; break; |
| 123 | case AV_SAMPLE_FMT_S32: |
| 124 | s->noise *= INT32_MAX; |
| 125 | s->silencedetect = silencedetect_s32; |
| 126 | break; |
| 127 | case AV_SAMPLE_FMT_S16: |
| 128 | s->noise *= INT16_MAX; |
| 129 | s->silencedetect = silencedetect_s16; |
| 130 | break; |
| 131 | } |
| 132 | |
| 133 | return 0; |
| 134 | } |
| 135 | |
| 136 | static int filter_frame(AVFilterLink *inlink, AVFrame *insamples) |
| 137 | { |
| 138 | SilenceDetectContext *s = inlink->dst->priv; |
| 139 | const int nb_channels = inlink->channels; |
| 140 | const int srate = inlink->sample_rate; |
| 141 | const int nb_samples = insamples->nb_samples * nb_channels; |
| 142 | const int64_t nb_samples_notify = srate * s->duration * nb_channels; |
| 143 | |
| 144 | // scale number of null samples to the new sample rate |
| 145 | if (s->last_sample_rate && s->last_sample_rate != srate) |
| 146 | s->nb_null_samples = srate * s->nb_null_samples / s->last_sample_rate; |
| 147 | s->last_sample_rate = srate; |
| 148 | |
| 149 | // TODO: document metadata |
| 150 | s->silencedetect(s, insamples, nb_samples, nb_samples_notify, |
| 151 | inlink->time_base); |
| 152 | |
| 153 | return ff_filter_frame(inlink->dst->outputs[0], insamples); |
| 154 | } |
| 155 | |
| 156 | static int query_formats(AVFilterContext *ctx) |
| 157 | { |
| 158 | AVFilterFormats *formats = NULL; |
| 159 | AVFilterChannelLayouts *layouts = NULL; |
| 160 | static const enum AVSampleFormat sample_fmts[] = { |
| 161 | AV_SAMPLE_FMT_DBL, |
| 162 | AV_SAMPLE_FMT_FLT, |
| 163 | AV_SAMPLE_FMT_S32, |
| 164 | AV_SAMPLE_FMT_S16, |
| 165 | AV_SAMPLE_FMT_NONE |
| 166 | }; |
| 167 | |
| 168 | layouts = ff_all_channel_layouts(); |
| 169 | if (!layouts) |
| 170 | return AVERROR(ENOMEM); |
| 171 | ff_set_common_channel_layouts(ctx, layouts); |
| 172 | |
| 173 | formats = ff_make_format_list(sample_fmts); |
| 174 | if (!formats) |
| 175 | return AVERROR(ENOMEM); |
| 176 | ff_set_common_formats(ctx, formats); |
| 177 | |
| 178 | formats = ff_all_samplerates(); |
| 179 | if (!formats) |
| 180 | return AVERROR(ENOMEM); |
| 181 | ff_set_common_samplerates(ctx, formats); |
| 182 | |
| 183 | return 0; |
| 184 | } |
| 185 | |
| 186 | static const AVFilterPad silencedetect_inputs[] = { |
| 187 | { |
| 188 | .name = "default", |
| 189 | .type = AVMEDIA_TYPE_AUDIO, |
| 190 | .config_props = config_input, |
| 191 | .filter_frame = filter_frame, |
| 192 | }, |
| 193 | { NULL } |
| 194 | }; |
| 195 | |
| 196 | static const AVFilterPad silencedetect_outputs[] = { |
| 197 | { |
| 198 | .name = "default", |
| 199 | .type = AVMEDIA_TYPE_AUDIO, |
| 200 | }, |
| 201 | { NULL } |
| 202 | }; |
| 203 | |
| 204 | AVFilter ff_af_silencedetect = { |
| 205 | .name = "silencedetect", |
| 206 | .description = NULL_IF_CONFIG_SMALL("Detect silence."), |
| 207 | .priv_size = sizeof(SilenceDetectContext), |
| 208 | .query_formats = query_formats, |
| 209 | .inputs = silencedetect_inputs, |
| 210 | .outputs = silencedetect_outputs, |
| 211 | .priv_class = &silencedetect_class, |
| 212 | }; |