ffmpeg/libavfilter/af_silenceremove.c

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/*
* Copyright (c) 2001 Heikki Leinonen
* Copyright (c) 2001 Chris Bagwell
* Copyright (c) 2003 Donnie Smith
* Copyright (c) 2014 Paul B Mahol
*
* 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
*/
#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"
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;
double start_threshold;
int stop_periods;
int64_t stop_duration;
double stop_threshold;
double *start_holdoff;
size_t start_holdoff_offset;
size_t start_holdoff_end;
int start_found_periods;
double *stop_holdoff;
size_t stop_holdoff_offset;
size_t stop_holdoff_end;
int stop_found_periods;
double *window;
double *window_current;
double *window_end;
int window_size;
double rms_sum;
int leave_silence;
int restart;
int64_t next_pts;
} SilenceRemoveContext;
#define OFFSET(x) offsetof(SilenceRemoveContext, x)
#define FLAGS 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, FLAGS },
{ "start_duration", NULL, OFFSET(start_duration), AV_OPT_TYPE_DURATION, {.i64=0}, 0, 9000, FLAGS },
{ "start_threshold", NULL, OFFSET(start_threshold), AV_OPT_TYPE_DOUBLE, {.dbl=0}, 0, DBL_MAX, FLAGS },
{ "stop_periods", NULL, OFFSET(stop_periods), AV_OPT_TYPE_INT, {.i64=0}, -9000, 9000, FLAGS },
{ "stop_duration", NULL, OFFSET(stop_duration), AV_OPT_TYPE_DURATION, {.i64=0}, 0, 9000, FLAGS },
{ "stop_threshold", NULL, OFFSET(stop_threshold), AV_OPT_TYPE_DOUBLE, {.dbl=0}, 0, DBL_MAX, FLAGS },
{ "leave_silence", NULL, OFFSET(leave_silence), AV_OPT_TYPE_INT, {.i64=0}, 0, 1, FLAGS },
{ NULL }
};
AVFILTER_DEFINE_CLASS(silenceremove);
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;
}
return 0;
}
static void clear_rms(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->rms_sum = 0;
}
static int config_input(AVFilterLink *inlink)
{
AVFilterContext *ctx = inlink->dst;
SilenceRemoveContext *s = ctx->priv;
s->window_size = (inlink->sample_rate / 50) * inlink->channels;
s->window = av_malloc_array(s->window_size, sizeof(*s->window));
if (!s->window)
return AVERROR(ENOMEM);
clear_rms(s);
s->start_duration = av_rescale(s->start_duration, inlink->sample_rate,
AV_TIME_BASE);
s->stop_duration = av_rescale(s->stop_duration, 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_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_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 int config_output(AVFilterLink *outlink)
{
outlink->flags |= FF_LINK_FLAG_REQUEST_LOOP;
return 0;
}
static double compute_rms(SilenceRemoveContext *s, double sample)
{
double new_sum;
new_sum = s->rms_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->rms_sum -= *s->window_current;
*s->window_current = sample * sample;
s->rms_sum += *s->window_current;
s->window_current++;
if (s->window_current >= s->window_end)
s->window_current = s->window;
}
static void flush(AVFrame *out, AVFilterLink *outlink,
int *nb_samples_written, int *ret)
{
if (*nb_samples_written) {
out->nb_samples = *nb_samples_written / outlink->channels;
*ret = ff_filter_frame(outlink, out);
*nb_samples_written = 0;
} else {
av_frame_free(&out);
}
}
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;
switch (s->mode) {
case SILENCE_TRIM:
silence_trim:
nbs = in->nb_samples - nb_samples_read / inlink->channels;
if (!nbs)
break;
for (i = 0; i < nbs; i++) {
threshold = 0;
for (j = 0; j < inlink->channels; j++) {
threshold |= compute_rms(s, ibuf[j]) > s->start_threshold;
}
if (threshold) {
for (j = 0; j < inlink->channels; j++) {
update_rms(s, *ibuf);
s->start_holdoff[s->start_holdoff_end++] = *ibuf++;
nb_samples_read++;
}
if (s->start_holdoff_end >= s->start_duration * inlink->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;
}
} else {
s->start_holdoff_end = 0;
for (j = 0; j < inlink->channels; j++)
update_rms(s, ibuf[j]);
ibuf += inlink->channels;
nb_samples_read += inlink->channels;
}
}
break;
case SILENCE_TRIM_FLUSH:
silence_trim_flush:
nbs = s->start_holdoff_end - s->start_holdoff_offset;
nbs -= nbs % inlink->channels;
if (!nbs)
break;
out = ff_get_audio_buffer(inlink, nbs / inlink->channels);
if (!out) {
av_frame_free(&in);
return AVERROR(ENOMEM);
}
memcpy(out->data[0], &s->start_holdoff[s->start_holdoff_offset],
nbs * sizeof(double));
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->mode = SILENCE_COPY;
goto silence_copy;
}
break;
case SILENCE_COPY:
silence_copy:
nbs = in->nb_samples - nb_samples_read / inlink->channels;
if (!nbs)
break;
out = ff_get_audio_buffer(inlink, 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++) {
threshold = 1;
for (j = 0; j < inlink->channels; j++)
threshold &= compute_rms(s, ibuf[j]) > s->stop_threshold;
if (threshold && s->stop_holdoff_end && !s->leave_silence) {
s->mode = SILENCE_COPY_FLUSH;
flush(out, outlink, &nb_samples_written, &ret);
goto silence_copy_flush;
} else if (threshold) {
for (j = 0; j < inlink->channels; j++) {
update_rms(s, *ibuf);
*obuf++ = *ibuf++;
nb_samples_read++;
nb_samples_written++;
}
} else if (!threshold) {
for (j = 0; j < inlink->channels; j++) {
update_rms(s, *ibuf);
if (s->leave_silence) {
*obuf++ = *ibuf;
nb_samples_written++;
}
s->stop_holdoff[s->stop_holdoff_end++] = *ibuf++;
nb_samples_read++;
}
if (s->stop_holdoff_end >= s->stop_duration * inlink->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(out, outlink, &nb_samples_written, &ret);
goto silence_stop;
} else {
s->stop_found_periods = 0;
s->start_found_periods = 0;
s->start_holdoff_offset = 0;
s->start_holdoff_end = 0;
clear_rms(s);
s->mode = SILENCE_TRIM;
flush(out, outlink, &nb_samples_written, &ret);
goto silence_trim;
}
}
s->mode = SILENCE_COPY_FLUSH;
flush(out, outlink, &nb_samples_written, &ret);
goto silence_copy_flush;
}
}
}
flush(out, outlink, &nb_samples_written, &ret);
} else {
memcpy(obuf, ibuf, sizeof(double) * nbs * inlink->channels);
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 % inlink->channels;
if (!nbs)
break;
out = ff_get_audio_buffer(inlink, nbs / inlink->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;
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->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));
ret = ff_filter_frame(ctx->inputs[0], 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_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 av_cold void uninit(AVFilterContext *ctx)
{
SilenceRemoveContext *s = ctx->priv;
av_freep(&s->start_holdoff);
av_freep(&s->stop_holdoff);
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,
.config_props = config_output,
.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,
};