static int filter_frame(AVFilterLink *inlink, AVFrame *in)
{
AVFilterContext *ctx = inlink->dst;
AVFilterLink *outlink = ctx->outputs[0];
AudioGateContext *s = ctx->priv;
const double *src = (const double *)in->data[0];
const double makeup = s->makeup;
const double attack_coeff = s->attack_coeff;
const double release_coeff = s->release_coeff;
const double level_in = s->level_in;
AVFrame *out;
double *dst;
int n, c;
if (av_frame_is_writable(in)) {
out = in;
} else {
out = ff_get_audio_buffer(inlink, in->nb_samples);
if (!out) {
av_frame_free(&in);
return AVERROR(ENOMEM);
}
av_frame_copy_props(out, in);
}
dst = (double *)out->data[0];
for (n = 0; n < in->nb_samples; n++, src += inlink->channels, dst += inlink->channels) {
double abs_sample = fabs(src[0]), gain = 1.0;
for (c = 0; c < inlink->channels; c++)
dst[c] = src[c] * level_in;
if (s->link == 1) {
for (c = 1; c < inlink->channels; c++)
abs_sample = FFMAX(fabs(src[c]), abs_sample);
} else {
for (c = 1; c < inlink->channels; c++)
abs_sample += fabs(src[c]);
abs_sample /= inlink->channels;
}
if (s->detection)
abs_sample *= abs_sample;
s->lin_slope += (abs_sample - s->lin_slope) * (abs_sample > s->lin_slope ? attack_coeff : release_coeff);
if (s->lin_slope > 0.0)
gain = output_gain(s->lin_slope, s->ratio, s->thres,
s->knee, s->knee_start, s->knee_stop,
s->lin_knee_stop, s->range);
for (c = 0; c < inlink->channels; c++)
dst[c] *= gain * makeup;
}
if (out != in)
av_frame_free(&in);
return ff_filter_frame(outlink, out);
}
static void compressor(SidechainCompressContext *s,
const double *src, double *dst, const double *scsrc, int nb_samples,
double level_in, double level_sc,
AVFilterLink *inlink, AVFilterLink *sclink)
{
const double makeup = s->makeup;
const double mix = s->mix;
int i, c;
for (i = 0; i < nb_samples; i++) {
double abs_sample, gain = 1.0;
abs_sample = fabs(scsrc[0] * level_sc);
if (s->link == 1) {
for (c = 1; c < sclink->channels; c++)
abs_sample = FFMAX(fabs(scsrc[c] * level_sc), abs_sample);
} else {
for (c = 1; c < sclink->channels; c++)
abs_sample += fabs(scsrc[c] * level_sc);
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->detection ? s->adj_knee_start : 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 < inlink->channels; c++)
dst[c] = src[c] * level_in * (gain * makeup * mix + (1. - mix));
src += inlink->channels;
dst += inlink->channels;
scsrc += sclink->channels;
}
}