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avfilter/af_stereotools: introduce different balance modes 

Signed-off-by: Paul B Mahol <onemda@gmail.com>
This commit is contained in:
Paul B Mahol 2017-05-15 19:56:55 +02:00
parent 88896c4619
commit 9bebad86c7
2 changed files with 66 additions and 5 deletions
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17
doc/filters.texi
View File

@ -3669,6 +3669,23 @@ Set S/C level. Default is 1. Allowed range is from 1 to 100.
@item phase
Set the stereo phase in degrees. Default is 0. Allowed range is from 0 to 360.
@item bmode_in, bmode_out
Set balance mode for balance_in/balance_out option.
Can be one of the following:
@table @samp
@item balance
Classic balance mode. Attenuate one channel at time.
Gain is raised up to 1.
@item amplitude
Similar as classic mode above but gain is raised up to 2.
@item power
Equal power distribution, from -6dB to +6dB range.
@end table
@end table
@subsection Examples

54
libavfilter/af_stereotools.c
View File

@ -33,6 +33,8 @@ typedef struct StereoToolsContext {
int phase_l;
int phase_r;
int mode;
int bmode_in;
int bmode_out;
double slev;
double sbal;
double mlev;
@ -83,6 +85,11 @@ static const AVOption stereotools_options[] = {
{ "delay", "set delay", OFFSET(delay), AV_OPT_TYPE_DOUBLE, {.dbl=0}, -20, 20, A },
{ "sclevel", "set S/C level", OFFSET(sc_level), AV_OPT_TYPE_DOUBLE, {.dbl=1}, 1, 100, A },
{ "phase", "set stereo phase", OFFSET(phase), AV_OPT_TYPE_DOUBLE, {.dbl=0}, 0, 360, A },
{ "bmode_in", "set balance in mode", OFFSET(bmode_in), AV_OPT_TYPE_INT, {.i64=0}, 0, 2, A, "bmode" },
{ "balance", 0, 0, AV_OPT_TYPE_CONST, {.i64=0}, 0, 0, A, "bmode" },
{ "amplitude", 0, 0, AV_OPT_TYPE_CONST, {.i64=1}, 0, 0, A, "bmode" },
{ "power", 0, 0, AV_OPT_TYPE_CONST, {.i64=2}, 0, 0, A, "bmode" },
{ "bmode_out", "set balance out mode", OFFSET(bmode_out), AV_OPT_TYPE_INT, {.i64=0}, 0, 2, A, "bmode" },
{ NULL }
};
@ -167,13 +174,31 @@ static int filter_frame(AVFilterLink *inlink, AVFrame *in)
dst = (double *)out->data[0];
for (n = 0; n < in->nb_samples; n++, src += 2, dst += 2) {
double L = src[0], R = src[1], l, r, m, S;
double L = src[0], R = src[1], l, r, m, S, gl, gr, gd;
L *= level_in;
R *= level_in;
L *= 1. - FFMAX(0., balance_in);
R *= 1. + FFMIN(0., balance_in);
gl = 1. - FFMAX(0., balance_in);
gr = 1. + FFMIN(0., balance_in);
switch (s->bmode_in) {
case 1:
gd = gl - gr;
gl = 1. + gd;
gr = 1. - gd;
break;
case 2:
if (balance_in < 0.) {
gr = FFMAX(0.5, gr);
gl = 1. / gr;
} else if (balance_in > 0.) {
gl = FFMAX(0.5, gl);
gr = 1. / gl;
}
break;
}
L *= gl;
R *= gr;
if (s->softclip) {
R = s->inv_atan_shape * atan(R * sc_level);
@ -253,8 +278,27 @@ static int filter_frame(AVFilterLink *inlink, AVFrame *in)
s->pos = (s->pos + 2) % s->length;
L *= 1. - FFMAX(0., balance_out);
R *= 1. + FFMIN(0., balance_out);
gl = 1. - FFMAX(0., balance_out);
gr = 1. + FFMIN(0., balance_out);
switch (s->bmode_out) {
case 1:
gd = gl - gr;
gl = 1. + gd;
gr = 1. - gd;
break;
case 2:
if (balance_out < 0.) {
gr = FFMAX(0.5, gr);
gl = 1. / gr;
} else if (balance_out > 0.) {
gl = FFMAX(0.5, gl);
gr = 1. / gl;
}
break;
}
L *= gl;
R *= gr;
L *= level_out;
R *= level_out;