/*
* Copyright (C) 2001-2010 Krzysztof Foltman, Markus Schmidt, Thor Harald Johansen and others
* Copyright (c) 2015 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
*/
/**
* @file
* Sidechain compressor filter
*/
#include "libavutil/avassert.h"
#include "libavutil/channel_layout.h"
#include "libavutil/common.h"
#include "libavutil/opt.h"
#include "audio.h"
#include "avfilter.h"
#include "formats.h"
#include "internal.h"
typedef struct SidechainCompressContext {
const AVClass *class;
double attack, attack_coeff;
double release, release_coeff;
double lin_slope;
double ratio;
double threshold;
double makeup;
double thres;
double knee;
double knee_start;
double knee_stop;
double lin_knee_start;
double compressed_knee_stop;
int link;
int detection;
AVFrame *input_frame[2];
} SidechainCompressContext;
#define OFFSET(x) offsetof(SidechainCompressContext, x)
#define A AV_OPT_FLAG_AUDIO_PARAM
#define F AV_OPT_FLAG_FILTERING_PARAM
static const AVOption sidechaincompress_options[] = {
{ "threshold", "set threshold", OFFSET(threshold), AV_OPT_TYPE_DOUBLE, {.dbl=0.125}, 0.000976563, 1, A|F },
{ "ratio", "set ratio", OFFSET(ratio), AV_OPT_TYPE_DOUBLE, {.dbl=2}, 1, 20, A|F },
{ "attack", "set attack", OFFSET(attack), AV_OPT_TYPE_DOUBLE, {.dbl=20}, 0.01, 2000, A|F },
{ "release", "set release", OFFSET(release), AV_OPT_TYPE_DOUBLE, {.dbl=250}, 0.01, 9000, A|F },
{ "makeup", "set make up gain", OFFSET(makeup), AV_OPT_TYPE_DOUBLE, {.dbl=2}, 1, 64, A|F },
{ "knee", "set knee", OFFSET(knee), AV_OPT_TYPE_DOUBLE, {.dbl=2.82843}, 1, 8, A|F },
{ "link", "set link type", OFFSET(link), AV_OPT_TYPE_INT, {.i64=0}, 0, 1, A|F, "link" },
{ "average", 0, 0, AV_OPT_TYPE_CONST, {.i64=0}, 0, 0, A|F, "link" },
{ "maximum", 0, 0, AV_OPT_TYPE_CONST, {.i64=1}, 0, 0, A|F, "link" },
{ "detection", "set detection", OFFSET(detection), AV_OPT_TYPE_INT, {.i64=1}, 0, 1, A|F, "detection" },
{ "peak", 0, 0, AV_OPT_TYPE_CONST, {.i64=0}, 0, 0, A|F, "detection" },
{ "rms", 0, 0, AV_OPT_TYPE_CONST, {.i64=1}, 0, 0, A|F, "detection" },
{ NULL }
};
AVFILTER_DEFINE_CLASS(sidechaincompress);
static av_cold int init(AVFilterContext *ctx)
{
SidechainCompressContext *s = ctx->priv;
s
->thres
= log(s
->threshold
); s
->lin_knee_start
= s
->threshold
/ sqrt(s
->knee
); s
->knee_start
= log(s
->lin_knee_start
); s
->knee_stop
= log(s
->threshold
* sqrt(s
->knee
)); s->compressed_knee_stop = (s->knee_stop - s->thres) / s->ratio + s->thres;
return 0;
}
static inline float hermite_interpolation(float x, float x0, float x1,
float p0, float p1,
float m0, float m1)
{
float width = x1 - x0;
float t = (x - x0) / width;
float t2, t3;
float ct0, ct1, ct2, ct3;
m0 *= width;
m1 *= width;
t2 = t*t;
t3 = t2*t;
ct0 = p0;
ct1 = m0;
ct2 = -3 * p0 - 2 * m0 + 3 * p1 - m1;
ct3 = 2 * p0 + m0 - 2 * p1 + m1;
return ct3 * t3 + ct2 * t2 + ct1 * t + ct0;
}
// A fake infinity value (because real infinity may break some hosts)
#define FAKE_INFINITY (65536.0 * 65536.0)
// Check for infinity (with appropriate-ish tolerance)
#define IS_FAKE_INFINITY(value) (fabs(value-FAKE_INFINITY) < 1.0)
static double output_gain(double lin_slope, double ratio, double thres,
double knee, double knee_start, double knee_stop,
double compressed_knee_stop, int detection)
{
double slope
= log(lin_slope
); double gain = 0.0;
double delta = 0.0;
if (detection)
slope *= 0.5;
if (IS_FAKE_INFINITY(ratio)) {
gain = thres;
delta = 0.0;
} else {
gain = (slope - thres) / ratio + thres;
delta = 1.0 / ratio;
}
if (knee > 1.0 && slope < knee_stop)
gain = hermite_interpolation(slope, knee_start, knee_stop,
knee_start, compressed_knee_stop,
1.0, delta);
return exp(gain
- slope
); }
static int filter_frame(AVFilterLink *link, AVFrame *frame)
{
AVFilterContext *ctx = link->dst;
SidechainCompressContext *s = ctx->priv;
AVFilterLink *sclink = ctx->inputs[1];
AVFilterLink *outlink = ctx->outputs[0];
const double makeup = s->makeup;
const double *scsrc;
double *sample;
int nb_samples;
int ret, i, c;
for (i = 0; i < 2; i++)
if (link == ctx->inputs[i])
break;
av_assert0(i < 2 && !s->input_frame[i]);
s->input_frame[i] = frame;
if (!s->input_frame[0] || !s->input_frame[1])
return 0;
nb_samples = FFMIN(s->input_frame[0]->nb_samples,
s->input_frame[1]->nb_samples);
sample = (double *)s->input_frame[0]->data[0];
scsrc = (const double *)s->input_frame[1]->data[0];
for (i = 0; i < nb_samples; i++) {
double abs_sample, gain = 1.0;
abs_sample = FFABS(scsrc[0]);
if (s->link == 1) {
for (c = 1; c < sclink->channels; c++)
abs_sample = FFMAX(FFABS(scsrc[c]), abs_sample);
} else {
for (c = 1; c < sclink->channels; c++)
abs_sample += FFABS(scsrc[c]);
abs_sample /= sclink->channels;
}
if (s->detection)
abs_sample *= abs_sample;
s->lin_slope += (abs_sample - s->lin_slope) * (abs_sample > s->lin_slope ? s->attack_coeff : s->release_coeff);
if (s->lin_slope > 0.0 && s->lin_slope > s->lin_knee_start)
gain = output_gain(s->lin_slope, s->ratio, s->thres, s->knee,
s->knee_start, s->knee_stop,
s->compressed_knee_stop, s->detection);
for (c = 0; c < outlink->channels; c++)
sample[c] *= gain * makeup;
sample += outlink->channels;
scsrc += sclink->channels;
}
ret = ff_filter_frame(outlink, s->input_frame[0]);
s->input_frame[0] = NULL;
av_frame_free(&s->input_frame[1]);
return ret;
}
static int request_frame(AVFilterLink *outlink)
{
AVFilterContext *ctx = outlink->src;
SidechainCompressContext *s = ctx->priv;
int i, ret;
/* get a frame on each input */
for (i = 0; i < 2; i++) {
AVFilterLink *inlink = ctx->inputs[i];
if (!s->input_frame[i] &&
(ret = ff_request_frame(inlink)) < 0)
return ret;
/* request the same number of samples on all inputs */
if (i == 0)
ctx->inputs[1]->request_samples = s->input_frame[0]->nb_samples;
}
return 0;
}
static int query_formats(AVFilterContext *ctx)
{
AVFilterFormats *formats;
AVFilterChannelLayouts *layouts = NULL;
static const enum AVSampleFormat sample_fmts[] = {
AV_SAMPLE_FMT_DBL,
AV_SAMPLE_FMT_NONE
};
int ret, i;
if (!ctx->inputs[0]->in_channel_layouts ||
!ctx->inputs[0]->in_channel_layouts->nb_channel_layouts) {
av_log(ctx, AV_LOG_WARNING,
"No channel layout for input 1\n");
return AVERROR(EAGAIN);
}
ff_add_channel_layout(&layouts, ctx->inputs[0]->in_channel_layouts->channel_layouts[0]);
if (!layouts)
return AVERROR(ENOMEM);
ff_channel_layouts_ref(layouts, &ctx->outputs[0]->in_channel_layouts);
for (i = 0; i < 2; i++) {
layouts = ff_all_channel_layouts();
if (!layouts)
return AVERROR(ENOMEM);
ff_channel_layouts_ref(layouts, &ctx->inputs[i]->out_channel_layouts);
}
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 int config_output(AVFilterLink *outlink)
{
AVFilterContext *ctx = outlink->src;
SidechainCompressContext *s = ctx->priv;
if (ctx->inputs[0]->sample_rate != ctx->inputs[1]->sample_rate) {
av_log(ctx, AV_LOG_ERROR,
"Inputs must have the same sample rate "
"%d for in0 vs %d for in1\n",
ctx->inputs[0]->sample_rate, ctx->inputs[1]->sample_rate);
return AVERROR(EINVAL);
}
outlink->sample_rate = ctx->inputs[0]->sample_rate;
outlink->time_base = ctx->inputs[0]->time_base;
outlink->channel_layout = ctx->inputs[0]->channel_layout;
outlink->channels = ctx->inputs[0]->channels;
s->attack_coeff = FFMIN(1.f, 1.f / (s->attack * outlink->sample_rate / 4000.f));
s->release_coeff = FFMIN(1.f, 1.f / (s->release * outlink->sample_rate / 4000.f));
return 0;
}
static const AVFilterPad sidechaincompress_inputs[] = {
{
.name = "main",
.type = AVMEDIA_TYPE_AUDIO,
.filter_frame = filter_frame,
.needs_writable = 1,
.needs_fifo = 1,
},{
.name = "sidechain",
.type = AVMEDIA_TYPE_AUDIO,
.filter_frame = filter_frame,
.needs_fifo = 1,
},
{ NULL }
};
static const AVFilterPad sidechaincompress_outputs[] = {
{
.name = "default",
.type = AVMEDIA_TYPE_AUDIO,
.config_props = config_output,
.request_frame = request_frame,
},
{ NULL }
};
AVFilter ff_af_sidechaincompress = {
.name = "sidechaincompress",
.description = NULL_IF_CONFIG_SMALL("Sidechain compressor."),
.priv_size = sizeof(SidechainCompressContext),
.priv_class = &sidechaincompress_class,
.init = init,
.query_formats = query_formats,
.inputs = sidechaincompress_inputs,
.outputs = sidechaincompress_outputs,
};