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avfilter/af_surround: add focus option

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And improve angle option handling.
This commit is contained in:
Paul B Mahol 2022-11-15 12:01:09 +01:00
parent c0b93c4f8b
commit 64031c5e65
2 changed files with 43 additions and 5 deletions
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4
doc/filters.texi
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@ -6674,6 +6674,10 @@ also all non-LFE output channels are subtracted with output LFE channel.
Set angle of stereo surround transform, Allowed range is from @var{0} to @var{360}.
Default is @var{90}.
@item focus
Set focus of stereo surround transform, Allowed range is from @var{-1} to @var{1}.
Default is @var{0}.
@item fc_in
Set front center input volume. By default, this is @var{1}.

44
libavfilter/af_surround.c
View File

@ -57,6 +57,7 @@ typedef struct AudioSurroundContext {
float lfe_out;
int lfe_mode;
float angle;
float focus;
int win_size;
int win_func;
float overlap;
@ -339,7 +340,17 @@ static int config_output(AVFilterLink *outlink)
return 0;
}
static void stereo_transform(float *x, float *y, float angle)
static float sqrf(float x)
{
return x * x;
}
static float r_distance(float a)
{
return fminf(sqrtf(1.f + sqrf(tanf(a))), sqrtf(1.f + sqrf(1.f / tanf(a))));
}
static void angle_transform(float *x, float *y, float angle)
{
float reference, r, a;
@ -350,11 +361,31 @@ static void stereo_transform(float *x, float *y, float angle)
r = hypotf(*x, *y);
a = atan2f(*x, *y);
r /= r_distance(a);
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);
a = M_PI + (-2.f * M_PI + reference) * (M_PI - fabsf(a)) * FFDIFFSIGN(a, 0.f) / (3.f * M_PI_2);
r *= r_distance(a);
*x = av_clipf(sinf(a) * r, -1.f, 1.f);
*y = av_clipf(cosf(a) * r, -1.f, 1.f);
}
static void focus_transform(float *x, float *y, float focus)
{
float a, r, ra;
if (focus == 0.f)
return;
a = atan2f(*x, *y);
ra = r_distance(a);
r = av_clipf(hypotf(*x, *y) / ra, 0.f, 1.f);
r = focus > 0.f ? 1.f - powf(1.f - r, 1.f + focus * 20.f) : powf(r, 1.f - focus * 20.f);
r *= ra;
*x = av_clipf(sinf(a) * r, -1.f, 1.f);
*y = av_clipf(cosf(a) * r, -1.f, 1.f);
}
@ -1405,6 +1436,7 @@ static void filter_stereo(AVFilterContext *ctx)
const float highcut = s->highcut;
const float lowcut = s->lowcut;
const float angle = s->angle;
const float focus = s->focus;
float *magtotal = s->mag_total;
float *lfemag = s->lfe_mag;
float *lphase = s->l_phase;
@ -1431,7 +1463,8 @@ static void filter_stereo(AVFilterContext *ctx)
phase_dif = 2.f * M_PI - phase_dif;
stereo_position(mag_dif, phase_dif, &x, &y);
stereo_transform(&x, &y, angle);
angle_transform(&x, &y, angle);
focus_transform(&x, &y, focus);
get_lfe(output_lfe, n, lowcut, highcut, &lfemag[n], &mag_total, lfe_mode);
xpos[n] = x;
@ -1473,7 +1506,7 @@ static void filter_surround(AVFilterContext *ctx)
phase_dif = 2.f * M_PI - phase_dif;
stereo_position(mag_dif, phase_dif, &x, &y);
stereo_transform(&x, &y, s->angle);
angle_transform(&x, &y, s->angle);
s->upmix_3_0(ctx, l_phase, r_phase, c_phase, c_mag, mag_total, x, y, n);
}
@ -1508,7 +1541,7 @@ static void filter_2_1(AVFilterContext *ctx)
phase_dif = 2.f * M_PI - phase_dif;
stereo_position(mag_dif, phase_dif, &x, &y);
stereo_transform(&x, &y, s->angle);
angle_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);
}
@ -2047,6 +2080,7 @@ static const AVOption surround_options[] = {
{ "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 },
{ "focus", "set soundfield transform focus", OFFSET(focus), AV_OPT_TYPE_FLOAT, {.dbl=0}, -1, 1, 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 },