[FFmpeg-cvslog] avfilter/af_sidechaincompress: implement mode option
Paul B Mahol
git at videolan.org
Wed Apr 17 17:39:05 EEST 2019
ffmpeg | branch: master | Paul B Mahol <onemda at gmail.com> | Wed Apr 17 14:31:13 2019 +0200| [a0559fcd81f42f446c93357a943699f9d44eeb79] | committer: Paul B Mahol
avfilter/af_sidechaincompress: implement mode option
> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=a0559fcd81f42f446c93357a943699f9d44eeb79
---
doc/filters.texi | 8 +++++++
libavfilter/af_sidechaincompress.c | 47 +++++++++++++++++++++++++++++++-------
2 files changed, 47 insertions(+), 8 deletions(-)
diff --git a/doc/filters.texi b/doc/filters.texi
index 867607d870..05a9ca3684 100644
--- a/doc/filters.texi
+++ b/doc/filters.texi
@@ -390,6 +390,10 @@ The filter accepts the following options:
@item level_in
Set input gain. Default is 1. Range is between 0.015625 and 64.
+ at item mode
+Set mode of compressor operation. Can be @code{upward} or @code{downward}.
+Default is @code{downward}.
+
@item threshold
If a signal of stream rises above this level it will affect the gain
reduction.
@@ -4247,6 +4251,10 @@ The filter accepts the following options:
@item level_in
Set input gain. Default is 1. Range is between 0.015625 and 64.
+ at item mode
+Set mode of compressor operation. Can be @code{upward} or @code{downward}.
+Default is @code{downward}.
+
@item threshold
If a signal of second stream raises above this level it will affect the gain
reduction of first stream.
diff --git a/libavfilter/af_sidechaincompress.c b/libavfilter/af_sidechaincompress.c
index 888049eaf0..219643acb6 100644
--- a/libavfilter/af_sidechaincompress.c
+++ b/libavfilter/af_sidechaincompress.c
@@ -54,10 +54,14 @@ typedef struct SidechainCompressContext {
double knee_start;
double knee_stop;
double lin_knee_start;
+ double lin_knee_stop;
double adj_knee_start;
+ double adj_knee_stop;
+ double compressed_knee_start;
double compressed_knee_stop;
int link;
int detection;
+ int mode;
AVAudioFifo *fifo[2];
int64_t pts;
@@ -69,6 +73,9 @@ typedef struct SidechainCompressContext {
static const AVOption options[] = {
{ "level_in", "set input gain", OFFSET(level_in), AV_OPT_TYPE_DOUBLE, {.dbl=1}, 0.015625, 64, A|F },
+ { "mode", "set mode", OFFSET(mode), AV_OPT_TYPE_INT, {.i64=0}, 0, 1, A|F, "mode" },
+ { "downward",0, 0, AV_OPT_TYPE_CONST, {.i64=0}, 0, 0, A|F, "mode" },
+ { "upward", 0, 0, AV_OPT_TYPE_CONST, {.i64=1}, 0, 0, A|F, "mode" },
{ "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 },
@@ -97,7 +104,9 @@ AVFILTER_DEFINE_CLASS(sidechaincompress);
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 compressed_knee_start,
+ double compressed_knee_stop,
+ int detection, int mode)
{
double slope = log(lin_slope);
double gain = 0.0;
@@ -114,10 +123,17 @@ static double output_gain(double lin_slope, double ratio, double 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);
+ if (mode) {
+ if (knee > 1.0 && slope > knee_start)
+ gain = hermite_interpolation(slope, knee_stop, knee_start,
+ knee_stop, compressed_knee_start,
+ 1.0, delta);
+ } else {
+ 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);
}
@@ -129,9 +145,12 @@ static int compressor_config_output(AVFilterLink *outlink)
s->thres = log(s->threshold);
s->lin_knee_start = s->threshold / sqrt(s->knee);
+ s->lin_knee_stop = s->threshold * sqrt(s->knee);
s->adj_knee_start = s->lin_knee_start * s->lin_knee_start;
+ s->adj_knee_stop = s->lin_knee_stop * s->lin_knee_stop;
s->knee_start = log(s->lin_knee_start);
- s->knee_stop = log(s->threshold * sqrt(s->knee));
+ s->knee_stop = log(s->lin_knee_stop);
+ s->compressed_knee_start = (s->knee_start - s->thres) / s->ratio + s->thres;
s->compressed_knee_stop = (s->knee_stop - s->thres) / s->ratio + s->thres;
s->attack_coeff = FFMIN(1., 1. / (s->attack * outlink->sample_rate / 4000.));
@@ -151,6 +170,8 @@ static void compressor(SidechainCompressContext *s,
for (i = 0; i < nb_samples; i++) {
double abs_sample, gain = 1.0;
+ double detector;
+ int detected;
abs_sample = fabs(scsrc[0] * level_sc);
@@ -169,10 +190,20 @@ static void compressor(SidechainCompressContext *s,
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))
+ if (s->mode) {
+ detector = (s->detection ? s->adj_knee_stop : s->lin_knee_stop);
+ detected = s->lin_slope < detector;
+ } else {
+ detector = (s->detection ? s->adj_knee_start : s->lin_knee_start);
+ detected = s->lin_slope > detector;
+ }
+
+ if (s->lin_slope > 0.0 && detected)
gain = output_gain(s->lin_slope, s->ratio, s->thres, s->knee,
s->knee_start, s->knee_stop,
- s->compressed_knee_stop, s->detection);
+ s->compressed_knee_start,
+ s->compressed_knee_stop,
+ s->detection, s->mode);
for (c = 0; c < inlink->channels; c++)
dst[c] = src[c] * level_in * (gain * makeup * mix + (1. - mix));
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