This source file includes following definitions.
- compute_peak
- update_peak
- compute_rms
- update_rms
- init
- clear_window
- config_input
- flush
- filter_frame
- request_frame
- query_formats
- uninit
#include <float.h>
#include "libavutil/opt.h"
#include "libavutil/timestamp.h"
#include "audio.h"
#include "formats.h"
#include "avfilter.h"
#include "internal.h"
enum SilenceDetect {
D_PEAK,
D_RMS,
};
enum ThresholdMode {
T_ANY,
T_ALL,
};
enum SilenceMode {
SILENCE_TRIM,
SILENCE_TRIM_FLUSH,
SILENCE_COPY,
SILENCE_COPY_FLUSH,
SILENCE_STOP
};
typedef struct SilenceRemoveContext {
const AVClass *class;
enum SilenceMode mode;
int start_periods;
int64_t start_duration;
int64_t start_duration_opt;
double start_threshold;
int64_t start_silence;
int64_t start_silence_opt;
int start_mode;
int stop_periods;
int64_t stop_duration;
int64_t stop_duration_opt;
double stop_threshold;
int64_t stop_silence;
int64_t stop_silence_opt;
int stop_mode;
double *start_holdoff;
double *start_silence_hold;
size_t start_holdoff_offset;
size_t start_holdoff_end;
size_t start_silence_offset;
size_t start_silence_end;
int start_found_periods;
double *stop_holdoff;
double *stop_silence_hold;
size_t stop_holdoff_offset;
size_t stop_holdoff_end;
size_t stop_silence_offset;
size_t stop_silence_end;
int stop_found_periods;
double window_ratio;
double *window;
double *window_current;
double *window_end;
int window_size;
double sum;
int restart;
int64_t next_pts;
int detection;
void (*update)(struct SilenceRemoveContext *s, double sample);
double(*compute)(struct SilenceRemoveContext *s, double sample);
} SilenceRemoveContext;
#define OFFSET(x) offsetof(SilenceRemoveContext, x)
#define AF AV_OPT_FLAG_FILTERING_PARAM|AV_OPT_FLAG_AUDIO_PARAM
static const AVOption silenceremove_options[] = {
{ "start_periods", NULL, OFFSET(start_periods), AV_OPT_TYPE_INT, {.i64=0}, 0, 9000, AF },
{ "start_duration", "set start duration of non-silence part", OFFSET(start_duration_opt), AV_OPT_TYPE_DURATION, {.i64=0}, 0, INT32_MAX, AF },
{ "start_threshold", "set threshold for start silence detection", OFFSET(start_threshold), AV_OPT_TYPE_DOUBLE, {.dbl=0}, 0, DBL_MAX, AF },
{ "start_silence", "set start duration of silence part to keep", OFFSET(start_silence_opt), AV_OPT_TYPE_DURATION, {.i64=0}, 0, INT32_MAX, AF },
{ "start_mode", "set which channel will trigger trimming from start", OFFSET(start_mode), AV_OPT_TYPE_INT, {.i64=T_ANY}, T_ANY, T_ALL, AF, "mode" },
{ "any", 0, 0, AV_OPT_TYPE_CONST, {.i64=T_ANY}, 0, 0, AF, "mode" },
{ "all", 0, 0, AV_OPT_TYPE_CONST, {.i64=T_ALL}, 0, 0, AF, "mode" },
{ "stop_periods", NULL, OFFSET(stop_periods), AV_OPT_TYPE_INT, {.i64=0}, -9000, 9000, AF },
{ "stop_duration", "set stop duration of non-silence part", OFFSET(stop_duration_opt), AV_OPT_TYPE_DURATION, {.i64=0}, 0, INT32_MAX, AF },
{ "stop_threshold", "set threshold for stop silence detection", OFFSET(stop_threshold), AV_OPT_TYPE_DOUBLE, {.dbl=0}, 0, DBL_MAX, AF },
{ "stop_silence", "set stop duration of silence part to keep", OFFSET(stop_silence_opt), AV_OPT_TYPE_DURATION, {.i64=0}, 0, INT32_MAX, AF },
{ "stop_mode", "set which channel will trigger trimming from end", OFFSET(stop_mode), AV_OPT_TYPE_INT, {.i64=T_ANY}, T_ANY, T_ALL, AF, "mode" },
{ "detection", "set how silence is detected", OFFSET(detection), AV_OPT_TYPE_INT, {.i64=D_RMS}, D_PEAK,D_RMS, AF, "detection" },
{ "peak", "use absolute values of samples", 0, AV_OPT_TYPE_CONST, {.i64=D_PEAK},0, 0, AF, "detection" },
{ "rms", "use squared values of samples", 0, AV_OPT_TYPE_CONST, {.i64=D_RMS}, 0, 0, AF, "detection" },
{ "window", "set duration of window in seconds", OFFSET(window_ratio), AV_OPT_TYPE_DOUBLE, {.dbl=0.02}, 0, 10, AF },
{ NULL }
};
AVFILTER_DEFINE_CLASS(silenceremove);
static double compute_peak(SilenceRemoveContext *s, double sample)
{
double new_sum;
new_sum = s->sum;
new_sum -= *s->window_current;
new_sum += fabs(sample);
return new_sum / s->window_size;
}
static void update_peak(SilenceRemoveContext *s, double sample)
{
s->sum -= *s->window_current;
*s->window_current = fabs(sample);
s->sum += *s->window_current;
s->window_current++;
if (s->window_current >= s->window_end)
s->window_current = s->window;
}
static double compute_rms(SilenceRemoveContext *s, double sample)
{
double new_sum;
new_sum = s->sum;
new_sum -= *s->window_current;
new_sum += sample * sample;
return sqrt(new_sum / s->window_size);
}
static void update_rms(SilenceRemoveContext *s, double sample)
{
s->sum -= *s->window_current;
*s->window_current = sample * sample;
s->sum += *s->window_current;
s->window_current++;
if (s->window_current >= s->window_end)
s->window_current = s->window;
}
static av_cold int init(AVFilterContext *ctx)
{
SilenceRemoveContext *s = ctx->priv;
if (s->stop_periods < 0) {
s->stop_periods = -s->stop_periods;
s->restart = 1;
}
switch (s->detection) {
case D_PEAK:
s->update = update_peak;
s->compute = compute_peak;
break;
case D_RMS:
s->update = update_rms;
s->compute = compute_rms;
break;
}
return 0;
}
static void clear_window(SilenceRemoveContext *s)
{
memset(s->window, 0, s->window_size * sizeof(*s->window));
s->window_current = s->window;
s->window_end = s->window + s->window_size;
s->sum = 0;
}
static int config_input(AVFilterLink *inlink)
{
AVFilterContext *ctx = inlink->dst;
SilenceRemoveContext *s = ctx->priv;
s->next_pts = AV_NOPTS_VALUE;
s->window_size = FFMAX((inlink->sample_rate * s->window_ratio), 1) * inlink->channels;
s->window = av_malloc_array(s->window_size, sizeof(*s->window));
if (!s->window)
return AVERROR(ENOMEM);
clear_window(s);
s->start_duration = av_rescale(s->start_duration_opt, inlink->sample_rate,
AV_TIME_BASE);
s->start_silence = av_rescale(s->start_silence_opt, inlink->sample_rate,
AV_TIME_BASE);
s->stop_duration = av_rescale(s->stop_duration_opt, inlink->sample_rate,
AV_TIME_BASE);
s->stop_silence = av_rescale(s->stop_silence_opt, inlink->sample_rate,
AV_TIME_BASE);
s->start_holdoff = av_malloc_array(FFMAX(s->start_duration, 1),
sizeof(*s->start_holdoff) *
inlink->channels);
if (!s->start_holdoff)
return AVERROR(ENOMEM);
s->start_silence_hold = av_malloc_array(FFMAX(s->start_silence, 1),
sizeof(*s->start_silence_hold) *
inlink->channels);
if (!s->start_silence_hold)
return AVERROR(ENOMEM);
s->start_holdoff_offset = 0;
s->start_holdoff_end = 0;
s->start_found_periods = 0;
s->stop_holdoff = av_malloc_array(FFMAX(s->stop_duration, 1),
sizeof(*s->stop_holdoff) *
inlink->channels);
if (!s->stop_holdoff)
return AVERROR(ENOMEM);
s->stop_silence_hold = av_malloc_array(FFMAX(s->stop_silence, 1),
sizeof(*s->stop_silence_hold) *
inlink->channels);
if (!s->stop_silence_hold)
return AVERROR(ENOMEM);
s->stop_holdoff_offset = 0;
s->stop_holdoff_end = 0;
s->stop_found_periods = 0;
if (s->start_periods)
s->mode = SILENCE_TRIM;
else
s->mode = SILENCE_COPY;
return 0;
}
static void flush(SilenceRemoveContext *s,
AVFrame *out, AVFilterLink *outlink,
int *nb_samples_written, int *ret, int flush_silence)
{
AVFrame *silence;
if (*nb_samples_written) {
out->nb_samples = *nb_samples_written / outlink->channels;
out->pts = s->next_pts;
s->next_pts += av_rescale_q(out->nb_samples,
(AVRational){1, outlink->sample_rate},
outlink->time_base);
*ret = ff_filter_frame(outlink, out);
if (*ret < 0)
return;
*nb_samples_written = 0;
} else {
av_frame_free(&out);
}
if (s->stop_silence_end <= 0 || !flush_silence)
return;
silence = ff_get_audio_buffer(outlink, s->stop_silence_end / outlink->channels);
if (!silence) {
*ret = AVERROR(ENOMEM);
return;
}
if (s->stop_silence_offset < s->stop_silence_end) {
memcpy(silence->data[0],
&s->stop_silence_hold[s->stop_silence_offset],
(s->stop_silence_end - s->stop_silence_offset) * sizeof(double));
}
if (s->stop_silence_offset > 0) {
memcpy(silence->data[0] + (s->stop_silence_end - s->stop_silence_offset) * sizeof(double),
&s->stop_silence_hold[0],
s->stop_silence_offset * sizeof(double));
}
s->stop_silence_offset = 0;
s->stop_silence_end = 0;
silence->pts = s->next_pts;
s->next_pts += av_rescale_q(silence->nb_samples,
(AVRational){1, outlink->sample_rate},
outlink->time_base);
*ret = ff_filter_frame(outlink, silence);
}
static int filter_frame(AVFilterLink *inlink, AVFrame *in)
{
AVFilterContext *ctx = inlink->dst;
AVFilterLink *outlink = ctx->outputs[0];
SilenceRemoveContext *s = ctx->priv;
int i, j, threshold, ret = 0;
int nbs, nb_samples_read, nb_samples_written;
double *obuf, *ibuf = (double *)in->data[0];
AVFrame *out;
nb_samples_read = nb_samples_written = 0;
if (s->next_pts == AV_NOPTS_VALUE)
s->next_pts = in->pts;
switch (s->mode) {
case SILENCE_TRIM:
silence_trim:
nbs = in->nb_samples - nb_samples_read / outlink->channels;
if (!nbs)
break;
for (i = 0; i < nbs; i++) {
if (s->start_mode == T_ANY) {
threshold = 0;
for (j = 0; j < outlink->channels; j++) {
threshold |= s->compute(s, ibuf[j]) > s->start_threshold;
}
} else {
threshold = 1;
for (j = 0; j < outlink->channels; j++) {
threshold &= s->compute(s, ibuf[j]) > s->start_threshold;
}
}
if (threshold) {
for (j = 0; j < outlink->channels; j++) {
s->update(s, *ibuf);
s->start_holdoff[s->start_holdoff_end++] = *ibuf++;
}
nb_samples_read += outlink->channels;
if (s->start_holdoff_end >= s->start_duration * outlink->channels) {
if (++s->start_found_periods >= s->start_periods) {
s->mode = SILENCE_TRIM_FLUSH;
goto silence_trim_flush;
}
s->start_holdoff_offset = 0;
s->start_holdoff_end = 0;
s->start_silence_offset = 0;
s->start_silence_end = 0;
}
} else {
s->start_holdoff_end = 0;
for (j = 0; j < outlink->channels; j++) {
s->update(s, ibuf[j]);
if (s->start_silence) {
s->start_silence_hold[s->start_silence_offset++] = ibuf[j];
s->start_silence_end = FFMIN(s->start_silence_end + 1, outlink->channels * s->start_silence);
if (s->start_silence_offset >= outlink->channels * s->start_silence) {
s->start_silence_offset = 0;
}
}
}
ibuf += outlink->channels;
nb_samples_read += outlink->channels;
}
}
break;
case SILENCE_TRIM_FLUSH:
silence_trim_flush:
nbs = s->start_holdoff_end - s->start_holdoff_offset;
nbs -= nbs % outlink->channels;
if (!nbs)
break;
out = ff_get_audio_buffer(outlink, nbs / outlink->channels + s->start_silence_end / outlink->channels);
if (!out) {
av_frame_free(&in);
return AVERROR(ENOMEM);
}
if (s->start_silence_end > 0) {
if (s->start_silence_offset < s->start_silence_end) {
memcpy(out->data[0],
&s->start_silence_hold[s->start_silence_offset],
(s->start_silence_end - s->start_silence_offset) * sizeof(double));
}
if (s->start_silence_offset > 0) {
memcpy(out->data[0] + (s->start_silence_end - s->start_silence_offset) * sizeof(double),
&s->start_silence_hold[0],
s->start_silence_offset * sizeof(double));
}
}
memcpy(out->data[0] + s->start_silence_end * sizeof(double),
&s->start_holdoff[s->start_holdoff_offset],
nbs * sizeof(double));
out->pts = s->next_pts;
s->next_pts += av_rescale_q(out->nb_samples,
(AVRational){1, outlink->sample_rate},
outlink->time_base);
s->start_holdoff_offset += nbs;
ret = ff_filter_frame(outlink, out);
if (s->start_holdoff_offset == s->start_holdoff_end) {
s->start_holdoff_offset = 0;
s->start_holdoff_end = 0;
s->start_silence_offset = 0;
s->start_silence_end = 0;
s->mode = SILENCE_COPY;
goto silence_copy;
}
break;
case SILENCE_COPY:
silence_copy:
nbs = in->nb_samples - nb_samples_read / outlink->channels;
if (!nbs)
break;
out = ff_get_audio_buffer(outlink, nbs);
if (!out) {
av_frame_free(&in);
return AVERROR(ENOMEM);
}
obuf = (double *)out->data[0];
if (s->stop_periods) {
for (i = 0; i < nbs; i++) {
if (s->stop_mode == T_ANY) {
threshold = 0;
for (j = 0; j < outlink->channels; j++) {
threshold |= s->compute(s, ibuf[j]) > s->stop_threshold;
}
} else {
threshold = 1;
for (j = 0; j < outlink->channels; j++) {
threshold &= s->compute(s, ibuf[j]) > s->stop_threshold;
}
}
if (threshold && s->stop_holdoff_end && !s->stop_silence) {
s->mode = SILENCE_COPY_FLUSH;
flush(s, out, outlink, &nb_samples_written, &ret, 0);
goto silence_copy_flush;
} else if (threshold) {
for (j = 0; j < outlink->channels; j++) {
s->update(s, *ibuf);
*obuf++ = *ibuf++;
}
nb_samples_read += outlink->channels;
nb_samples_written += outlink->channels;
} else if (!threshold) {
for (j = 0; j < outlink->channels; j++) {
s->update(s, *ibuf);
if (s->stop_silence) {
s->stop_silence_hold[s->stop_silence_offset++] = *ibuf;
s->stop_silence_end = FFMIN(s->stop_silence_end + 1, outlink->channels * s->stop_silence);
if (s->stop_silence_offset >= outlink->channels * s->stop_silence) {
s->stop_silence_offset = 0;
}
}
s->stop_holdoff[s->stop_holdoff_end++] = *ibuf++;
}
nb_samples_read += outlink->channels;
if (s->stop_holdoff_end >= s->stop_duration * outlink->channels) {
if (++s->stop_found_periods >= s->stop_periods) {
s->stop_holdoff_offset = 0;
s->stop_holdoff_end = 0;
if (!s->restart) {
s->mode = SILENCE_STOP;
flush(s, out, outlink, &nb_samples_written, &ret, 1);
goto silence_stop;
} else {
s->stop_found_periods = 0;
s->start_found_periods = 0;
s->start_holdoff_offset = 0;
s->start_holdoff_end = 0;
s->start_silence_offset = 0;
s->start_silence_end = 0;
clear_window(s);
s->mode = SILENCE_TRIM;
flush(s, out, outlink, &nb_samples_written, &ret, 1);
goto silence_trim;
}
}
s->mode = SILENCE_COPY_FLUSH;
flush(s, out, outlink, &nb_samples_written, &ret, 0);
goto silence_copy_flush;
}
}
}
flush(s, out, outlink, &nb_samples_written, &ret, 0);
} else {
memcpy(obuf, ibuf, sizeof(double) * nbs * outlink->channels);
out->pts = s->next_pts;
s->next_pts += av_rescale_q(out->nb_samples,
(AVRational){1, outlink->sample_rate},
outlink->time_base);
ret = ff_filter_frame(outlink, out);
}
break;
case SILENCE_COPY_FLUSH:
silence_copy_flush:
nbs = s->stop_holdoff_end - s->stop_holdoff_offset;
nbs -= nbs % outlink->channels;
if (!nbs)
break;
out = ff_get_audio_buffer(outlink, nbs / outlink->channels);
if (!out) {
av_frame_free(&in);
return AVERROR(ENOMEM);
}
memcpy(out->data[0], &s->stop_holdoff[s->stop_holdoff_offset],
nbs * sizeof(double));
s->stop_holdoff_offset += nbs;
out->pts = s->next_pts;
s->next_pts += av_rescale_q(out->nb_samples,
(AVRational){1, outlink->sample_rate},
outlink->time_base);
ret = ff_filter_frame(outlink, out);
if (s->stop_holdoff_offset == s->stop_holdoff_end) {
s->stop_holdoff_offset = 0;
s->stop_holdoff_end = 0;
s->stop_silence_offset = 0;
s->stop_silence_end = 0;
s->mode = SILENCE_COPY;
goto silence_copy;
}
break;
case SILENCE_STOP:
silence_stop:
break;
}
av_frame_free(&in);
return ret;
}
static int request_frame(AVFilterLink *outlink)
{
AVFilterContext *ctx = outlink->src;
SilenceRemoveContext *s = ctx->priv;
int ret;
ret = ff_request_frame(ctx->inputs[0]);
if (ret == AVERROR_EOF && (s->mode == SILENCE_COPY_FLUSH ||
s->mode == SILENCE_COPY)) {
int nbs = s->stop_holdoff_end - s->stop_holdoff_offset;
if (nbs) {
AVFrame *frame;
frame = ff_get_audio_buffer(outlink, nbs / outlink->channels);
if (!frame)
return AVERROR(ENOMEM);
memcpy(frame->data[0], &s->stop_holdoff[s->stop_holdoff_offset],
nbs * sizeof(double));
frame->pts = s->next_pts;
s->next_pts += av_rescale_q(frame->nb_samples,
(AVRational){1, outlink->sample_rate},
outlink->time_base);
ret = ff_filter_frame(outlink, frame);
}
s->mode = SILENCE_STOP;
}
return ret;
}
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_NONE
};
int ret;
layouts = ff_all_channel_counts();
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 av_cold void uninit(AVFilterContext *ctx)
{
SilenceRemoveContext *s = ctx->priv;
av_freep(&s->start_holdoff);
av_freep(&s->start_silence_hold);
av_freep(&s->stop_holdoff);
av_freep(&s->stop_silence_hold);
av_freep(&s->window);
}
static const AVFilterPad silenceremove_inputs[] = {
{
.name = "default",
.type = AVMEDIA_TYPE_AUDIO,
.config_props = config_input,
.filter_frame = filter_frame,
},
{ NULL }
};
static const AVFilterPad silenceremove_outputs[] = {
{
.name = "default",
.type = AVMEDIA_TYPE_AUDIO,
.request_frame = request_frame,
},
{ NULL }
};
AVFilter ff_af_silenceremove = {
.name = "silenceremove",
.description = NULL_IF_CONFIG_SMALL("Remove silence."),
.priv_size = sizeof(SilenceRemoveContext),
.priv_class = &silenceremove_class,
.init = init,
.uninit = uninit,
.query_formats = query_formats,
.inputs = silenceremove_inputs,
.outputs = silenceremove_outputs,
};