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avfilter/af_surround: add angle option

This commit is contained in:
Paul B Mahol 2019-04-24 13:55:46 +02:00
parent e1cfb01b05
commit e1e0f94dc9
2 changed files with 29 additions and 0 deletions
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4
doc/filters.texi
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@ -4877,6 +4877,10 @@ In @var{add} mode, LFE channel is created from input audio and added to output.
In @var{sub} mode, LFE channel is created from input audio and added to output but
also all non-LFE output channels are subtracted with output LFE channel.
@item angle
Set angle of stereo surround transform, Allowed range is from @var{0} to @var{360}.
Default is @var{90}.
@item fc_in
Set front center input volume. By default, this is @var{1}.

25
libavfilter/af_surround.c
View File

@ -56,6 +56,7 @@ typedef struct AudioSurroundContext {
float lfe_in;
float lfe_out;
int lfe_mode;
float angle;
int win_size;
int win_func;
float overlap;
@ -312,6 +313,26 @@ static int config_output(AVFilterLink *outlink)
return 0;
}
static void stereo_transform(float *x, float *y, float angle)
{
float reference, r, a;
if (angle == 90.f)
return;
reference = angle * M_PI / 180.f;
r = hypotf(*x, *y);
a = atan2f(*x, *y);
if (fabsf(a) <= M_PI_4)
a *= reference / M_PI_2;
else
a = M_PI + 2 * (-2 * M_PI + reference) * (M_PI - fabsf(a)) * FFDIFFSIGN(a, 0) / (3 * M_PI);
*x = av_clipf(sinf(a) * r, -1, 1);
*y = av_clipf(cosf(a) * r, -1, 1);
}
static void stereo_position(float a, float p, float *x, float *y)
{
*x = av_clipf(a+FFMAX(0, sinf(p-M_PI_2))*FFDIFFSIGN(a,0), -1, 1);
@ -1096,6 +1117,7 @@ static void filter_stereo(AVFilterContext *ctx)
phase_dif = 2 * M_PI - phase_dif;
stereo_position(mag_dif, phase_dif, &x, &y);
stereo_transform(&x, &y, s->angle);
s->upmix_stereo(ctx, l_phase, r_phase, c_phase, mag_total, x, y, n);
}
@ -1131,6 +1153,7 @@ static void filter_surround(AVFilterContext *ctx)
phase_dif = 2 * M_PI - phase_dif;
stereo_position(mag_dif, phase_dif, &x, &y);
stereo_transform(&x, &y, s->angle);
s->upmix_3_0(ctx, l_phase, r_phase, c_phase, c_mag, mag_total, x, y, n);
}
@ -1165,6 +1188,7 @@ static void filter_2_1(AVFilterContext *ctx)
phase_dif = 2 * M_PI - phase_dif;
stereo_position(mag_dif, phase_dif, &x, &y);
stereo_transform(&x, &y, s->angle);
s->upmix_2_1(ctx, l_phase, r_phase, c_phase, mag_total, lfe_re, lfe_im, x, y, n);
}
@ -1674,6 +1698,7 @@ static const AVOption surround_options[] = {
{ "lfe_mode", "set LFE channel mode", OFFSET(lfe_mode), AV_OPT_TYPE_INT, {.i64=0}, 0, 1, FLAGS, "lfe_mode" },
{ "add", "just add LFE channel", 0, AV_OPT_TYPE_CONST, {.i64=0}, 0, 1, FLAGS, "lfe_mode" },
{ "sub", "substract LFE channel with others", 0, AV_OPT_TYPE_CONST, {.i64=1}, 0, 1, FLAGS, "lfe_mode" },
{ "angle", "set soundfield transform angle", OFFSET(angle), AV_OPT_TYPE_FLOAT, {.dbl=90}, 0, 360, FLAGS },
{ "fc_in", "set front center channel input level", OFFSET(fc_in), AV_OPT_TYPE_FLOAT, {.dbl=1}, 0, 10, FLAGS },
{ "fc_out", "set front center channel output level", OFFSET(fc_out), AV_OPT_TYPE_FLOAT, {.dbl=1}, 0, 10, FLAGS },
{ "fl_in", "set front left channel input level", OFFSET(fl_in), AV_OPT_TYPE_FLOAT, {.dbl=1}, 0, 10, FLAGS },