lavfi/silencedetect: Add mono mode

In mono mode, silence is detected in any single channel instead of all
of them simultaneously
pull/283/head
Nicolas Gaullier 7 years ago committed by Paul B Mahol
parent ae1a8b0690
commit 95e47654bc
  1. 78
      libavfilter/af_silencedetect.c

@ -36,8 +36,10 @@ 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 mono; ///< mono mode : check each channel separately (default = check when ALL channels are silent)
int independant_channels; ///< number of entries in following arrays (always 1 in mono mode)
int64_t *nb_null_samples; ///< (array) current number of continuous zero samples
int64_t *start; ///< (array) 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,
@ -52,44 +54,55 @@ static const AVOption silencedetect_options[] = {
{ "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 },
{ "mono", "check each channel separately", OFFSET(mono), AV_OPT_TYPE_BOOL, {.i64=0.}, 0, 1, FLAGS },
{ NULL }
};
AVFILTER_DEFINE_CLASS(silencedetect);
static char *get_metadata_val(AVFrame *insamples, const char *key)
static void set_meta(AVFrame *insamples, int channel, const char *key, char *value)
{
AVDictionaryEntry *e = av_dict_get(insamples->metadata, key, NULL, 0);
return e && e->value ? e->value : NULL;
}
char key2[128];
if (channel)
snprintf(key2, sizeof(key2), "lavfi.%s.%d", key, channel);
else
snprintf(key2, sizeof(key2), "lavfi.%s", key);
av_dict_set(&insamples->metadata, key2, value, 0);
}
static av_always_inline void update(SilenceDetectContext *s, AVFrame *insamples,
int is_silence, int64_t nb_samples_notify,
int is_silence, int current_sample, int64_t nb_samples_notify,
AVRational time_base)
{
int channel = current_sample % s->independant_channels;
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);
if (!s->start[channel]) {
s->nb_null_samples[channel]++;
if (s->nb_null_samples[channel] >= nb_samples_notify) {
s->start[channel] = insamples->pts - (int64_t)(s->duration / av_q2d(time_base) + .5);
set_meta(insamples, s->mono ? channel + 1 : 0, "silence_start",
av_ts2timestr(s->start[channel], &time_base));
if (s->mono)
av_log(s, AV_LOG_INFO, "channel: %d | ", channel);
av_log(s, AV_LOG_INFO, "silence_start: %s\n",
get_metadata_val(insamples, "lavfi.silence_start"));
av_ts2timestr(s->start[channel], &time_base));
}
}
} 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"));
if (s->start[channel]) {
int64_t end_pts = insamples->pts;
int64_t duration_ts = end_pts - s->start[channel];
set_meta(insamples, s->mono ? channel + 1 : 0, "silence_end",
av_ts2timestr(end_pts, &time_base));
set_meta(insamples, s->mono ? channel + 1 : 0, "silence_duration",
av_ts2timestr(duration_ts, &time_base));
if (s->mono)
av_log(s, AV_LOG_INFO, "channel: %d | ", channel);
av_log(s, AV_LOG_INFO, "silence_end: %s | silence_duration: %s\n",
av_ts2timestr(end_pts, &time_base),
av_ts2timestr(duration_ts, &time_base));
}
s->nb_null_samples = s->start = 0;
s->nb_null_samples[channel] = s->start[channel] = 0;
}
}
@ -103,7 +116,7 @@ static void silencedetect_##name(SilenceDetectContext *s, AVFrame *insamples,
int i; \
\
for (i = 0; i < nb_samples; i++, p++) \
update(s, insamples, *p < noise && *p > -noise, \
update(s, insamples, *p < noise && *p > -noise, i, \
nb_samples_notify, time_base); \
}
@ -117,6 +130,14 @@ static int config_input(AVFilterLink *inlink)
AVFilterContext *ctx = inlink->dst;
SilenceDetectContext *s = ctx->priv;
s->independant_channels = s->mono ? inlink->channels : 1;
s->nb_null_samples = av_mallocz_array(sizeof(*s->nb_null_samples), s->independant_channels);
if (!s->nb_null_samples)
return AVERROR(ENOMEM);
s->start = av_mallocz_array(sizeof(*s->start), s->independant_channels);
if (!s->start)
return AVERROR(ENOMEM);
switch (inlink->format) {
case AV_SAMPLE_FMT_DBL: s->silencedetect = silencedetect_dbl; break;
case AV_SAMPLE_FMT_FLT: s->silencedetect = silencedetect_flt; break;
@ -139,11 +160,14 @@ static int filter_frame(AVFilterLink *inlink, AVFrame *insamples)
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;
const int64_t nb_samples_notify = srate * s->duration * (s->mono ? 1 : nb_channels);
int c;
// 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;
for (c = 0; c < s->independant_channels; c++) {
s->nb_null_samples[c] = srate * s->nb_null_samples[c] / s->last_sample_rate;
}
s->last_sample_rate = srate;
// TODO: document metadata

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