resample: tweak kaiser resample defaults

Ensure a 110 dB stopband. Set the alpha values accordingly.
This commit is contained in:
Wim Taymans 2025-11-20 16:55:09 +01:00
parent faf4641625
commit df075e6628

View file

@ -104,21 +104,21 @@ static inline void exp_config(struct resample *r)
#include "dbesi0.c" #include "dbesi0.c"
static const struct quality kaiser_qualities[] = { static const struct quality kaiser_qualities[] = {
{ 8, 0.53, 0.53, { 5.653260, 60.0, 0.50 }}, { 8, 0.530000, 0.530000, { 3.553376, 110.000000, 0.888064 }},
{ 16, 0.67, 0.67, { 6.204260, 65.0, 0.25 }}, { 16, 0.670000, 0.670000, { 3.553376, 110.000000, 0.444032 }},
{ 24, 0.75, 0.75, { 6.534860, 68.0, 0.18 }}, { 24, 0.750000, 0.750000, { 3.904154, 120.000000, 0.325043 }},
{ 32, 0.80, 0.80, { 6.975660, 72.0, 0.140 }}, { 32, 0.800000, 0.800000, { 4.254931, 130.000000, 0.265548 }},
{ 48, 0.85, 0.85, { 7.857260, 80.0, 0.105 }}, /* default */ { 48, 0.850000, 0.850000, { 4.254931, 130.000000, 0.177032 }},
{ 64, 0.88, 0.88, { 8.408260, 85.0, 0.085 }}, { 64, 0.880000, 0.880000, { 4.254931, 130.000000, 0.132774 }},
{ 80, 0.895, 0.895, { 9.510260, 95.0, 0.076 }}, { 80, 0.895000, 0.895000, { 4.254931, 130.000000, 0.106219 }},
{ 96, 0.910, 0.910, { 10.061260, 100.0, 0.067 }}, { 96, 0.910000, 0.910000, { 4.254931, 130.000000, 0.088516 }},
{ 128, 0.936, 0.936, { 10.612260, 105.0, 0.053 }}, { 128, 0.936000, 0.936000, { 4.254931, 130.000000, 0.066387 }},
{ 160, 0.950, 0.950, { 11.163260, 110.0, 0.0445 }}, { 160, 0.950000, 0.950000, { 4.254931, 130.000000, 0.053110 }},
{ 192, 0.960, 0.960, { 11.714260, 115.0, 0.039 }}, { 192, 0.960000, 0.960000, { 4.254931, 130.000000, 0.044258 }},
{ 256, 0.970, 0.970, { 12.265260, 120.0, 0.0305 }}, { 256, 0.970000, 0.970000, { 4.605709, 140.000000, 0.035914 }},
{ 512, 0.980, 0.980, { 13.367260, 130.0, 0.0166 }}, { 512, 0.980000, 0.980000, { 4.781097, 145.000000, 0.018637 }},
{ 768, 0.985, 0.985, { 14.689660, 142.0, 0.01216 }}, { 768, 0.985000, 0.985000, { 4.956486, 150.000000, 0.012878 }},
{ 1024, 0.990, 0.990, { 16.122260, 155.0, 0.01 }}, { 1024, 0.990000, 0.990000, { 5.131875, 155.000000, 0.009999 }},
}; };
static inline void kaiser_window(struct resample *r, double *w, double t, uint32_t n_taps) static inline void kaiser_window(struct resample *r, double *w, double t, uint32_t n_taps)
@ -132,20 +132,19 @@ static inline void kaiser_window(struct resample *r, double *w, double t, uint32
} }
} }
#if 0
static inline void kaiser_config(struct resample *r) static inline void kaiser_config(struct resample *r)
{ {
double A, B, dw, tr_bw; double A, B, dw, tr_bw, alpha;
uint32_t n; uint32_t n;
const struct quality *q = &window_info[r->config.window].qualities[r->quality];
A = r->config.params[RESAMPLE_PARAM_KAISER_SB_ATT]; if ((A = r->config.params[RESAMPLE_PARAM_KAISER_SB_ATT]) == 0.0)
if (A <= 0.0) A = q->params[RESAMPLE_PARAM_KAISER_SB_ATT];
A = 160; if ((tr_bw = r->config.params[RESAMPLE_PARAM_KAISER_TR_BW]) == 0.0)
tr_bw = r->config.params[RESAMPLE_PARAM_KAISER_TR_BW]; tr_bw = q->params[RESAMPLE_PARAM_KAISER_TR_BW];
if (tr_bw <= 0.0)
tr_bw = 0.0305;
/* calculate Beta */ if ((alpha = r->config.params[RESAMPLE_PARAM_KAISER_ALPHA]) == 0.0) {
/* calculate Beta and alpha */
if (A > 50) if (A > 50)
B = 0.1102 * (A - 8.7); B = 0.1102 * (A - 8.7);
else if (A >= 21) else if (A >= 21)
@ -153,23 +152,16 @@ static inline void kaiser_config(struct resample *r)
else else
B = 0.0; B = 0.0;
r->config.params[RESAMPLE_PARAM_KAISER_ALPHA] = B / M_PI;
}
if (r->config.n_taps == 0) {
/* calculate transition width in radians */ /* calculate transition width in radians */
dw = 2 * M_PI * (tr_bw); dw = 2 * M_PI * (tr_bw);
/* order of the filter */ /* order of the filter */
n = (uint32_t)((A - 8.0) / (2.285 * dw)); n = (uint32_t)((A - 8.0) / (2.285 * dw));
r->config.params[RESAMPLE_PARAM_KAISER_ALPHA] = B / M_PI;
r->config.n_taps = n + 1; r->config.n_taps = n + 1;
}
} }
#else
static inline void kaiser_config(struct resample *r)
{
const struct quality *q = &window_info[r->config.window].qualities[r->quality];
INHERIT_PARAM(&r->config, q, RESAMPLE_PARAM_KAISER_ALPHA);
INHERIT_PARAM(&r->config, q, RESAMPLE_PARAM_KAISER_SB_ATT);
INHERIT_PARAM(&r->config, q, RESAMPLE_PARAM_KAISER_TR_BW);
}
#endif
struct window_info window_info[] = { struct window_info window_info[] = {
[RESAMPLE_WINDOW_EXP] = { RESAMPLE_WINDOW_EXP, exp_window, [RESAMPLE_WINDOW_EXP] = { RESAMPLE_WINDOW_EXP, exp_window,