50 const float *coeffs =
s->coeffs;
54 nb_samples =
FFMIN(
s->nb_samples,
s->n -
s->pts);
61 memcpy(
frame->data[0], coeffs +
s->pts, nb_samples *
sizeof(
float));
102 float term = 1, sum = 1, last_sum, x2 = x / 2;
109 sum += term *= y * y;
110 }
while (sum != last_sum);
115 static float *
make_lpf(
int num_taps,
float Fc,
float beta,
float rho,
116 float scale,
int dc_norm)
118 int i, m = num_taps - 1;
119 float *
h =
av_calloc(num_taps,
sizeof(*
h)), sum = 0;
120 float mult = scale /
bessel_I_0(beta), mult1 = 1.f / (.5f * m + rho);
124 for (
i = 0;
i <= m / 2;
i++) {
125 float z =
i - .5f * m, x = z *
M_PI, y = z * mult1;
126 h[
i] = x ?
sinf(Fc * x) / x : Fc;
134 for (
i = 0; dc_norm &&
i < num_taps;
i++)
143 static const float coefs[][4] = {
144 {-6.784957e-10, 1.02856e-05, 0.1087556, -0.8988365 + .001},
145 {-6.897885e-10, 1.027433e-05, 0.10876, -0.8994658 + .002},
146 {-1.000683e-09, 1.030092e-05, 0.1087677, -0.9007898 + .003},
147 {-3.654474e-10, 1.040631e-05, 0.1087085, -0.8977766 + .006},
148 {8.106988e-09, 6.983091e-06, 0.1091387, -0.9172048 + .015},
149 {9.519571e-09, 7.272678e-06, 0.1090068, -0.9140768 + .025},
150 {-5.626821e-09, 1.342186e-05, 0.1083999, -0.9065452 + .05},
151 {-9.965946e-08, 5.073548e-05, 0.1040967, -0.7672778 + .085},
152 {1.604808e-07, -5.856462e-05, 0.1185998, -1.34824 + .1},
153 {-1.511964e-07, 6.363034e-05, 0.1064627, -0.9876665 + .18},
155 float realm = logf(tr_bw / .0005
f) / logf(2.
f);
156 float const *c0 = coefs[av_clip((
int)realm, 0,
FF_ARRAY_ELEMS(coefs) - 1)];
157 float const *
c1 = coefs[av_clip(1 + (
int)realm, 0,
FF_ARRAY_ELEMS(coefs) - 1)];
158 float b0 = ((c0[0] * att + c0[1]) * att + c0[2]) * att + c0[3];
159 float b1 = ((
c1[0] * att +
c1[1]) * att +
c1[2]) * att +
c1[3];
161 return b0 + (
b1 -
b0) * (realm - (
int)realm);
164 return .1102f * (att - 8.7f);
166 return .58417f *
powf(att - 20.96
f, .4
f) + .07886f * (att - 20.96f);
170 static void kaiser_params(
float att,
float Fc,
float tr_bw,
float *beta,
int *num_taps)
172 *beta = *beta < 0.f ?
kaiser_beta(att, tr_bw * .5
f / Fc): *beta;
173 att = att < 60.f ? (att - 7.95f) / (2.285
f *
M_PI * 2.
f) :
174 ((.0007528358f-1.577737e-05 * *beta) * *beta + 0.6248022
f) * *beta + .06186902f;
175 *num_taps = !*num_taps ? ceilf(att/tr_bw + 1) : *num_taps;
178 static float *
lpf(
float Fn,
float Fc,
float tbw,
int *num_taps,
float att,
float *beta,
int round)
182 if ((Fc /= Fn) <= 0.
f || Fc >= 1.
f) {
187 att = att ? att : 120.f;
193 *num_taps = av_clip(n, 11, 32767);
195 *num_taps = 1 + 2 * (
int)((
int)((*num_taps / 2) * Fc + .5
f) / Fc + .5f);
198 return make_lpf(*num_taps |= 1, Fc, *beta, 0.
f, 1.
f, 0);
203 for (
int i = 0;
i < n;
i++)
209 #define PACK(h, n) h[1] = h[n]
210 #define UNPACK(h, n) h[n] = h[1], h[n + 1] = h[1] = 0;
211 #define SQR(a) ((a) * (a))
223 float *pi_wraps, *
work, phase1 = (phase > 50.f ? 100.f - phase : phase) / 50.
f;
224 int i, work_len, begin,
end, imp_peak = 0, peak = 0;
225 float imp_sum = 0, peak_imp_sum = 0;
226 float prev_angle2 = 0, cum_2pi = 0, prev_angle1 = 0, cum_1pi = 0;
228 for (
i = *
len, work_len = 2 * 2 * 8;
i > 1; work_len <<= 1, i >>= 1);
231 work =
av_calloc((work_len + 2) + (work_len / 2 + 1),
sizeof(
float));
234 pi_wraps = &
work[work_len + 2];
240 s->rdft =
s->irdft =
NULL;
243 if (!
s->rdft || !
s->irdft) {
251 for (
i = 0;
i <= work_len;
i += 2) {
253 float detect = 2 *
M_PI;
254 float delta = angle - prev_angle2;
261 delta = angle - prev_angle1;
265 pi_wraps[
i >> 1] = cum_1pi;
274 for (
i = 0;
i < work_len;
i++)
275 work[
i] *= 2.
f / work_len;
277 for (
i = 1;
i < work_len / 2;
i++) {
279 work[
i + work_len / 2] = 0;
283 for (
i = 2;
i < work_len;
i += 2)
284 work[
i + 1] = phase1 *
i / work_len * pi_wraps[work_len >> 1] + (1 - phase1) * (
work[
i + 1] + pi_wraps[
i >> 1]) - pi_wraps[
i >> 1];
288 for (
i = 2;
i < work_len;
i += 2) {
296 for (
i = 0;
i < work_len;
i++)
297 work[
i] *= 2.
f / work_len;
300 for (
i = 0;
i <= (
int) (pi_wraps[work_len >> 1] /
M_PI + .5
f);
i++) {
302 if (fabs(imp_sum) > fabs(peak_imp_sum)) {
303 peak_imp_sum = imp_sum;
310 while (peak && fabsf(
work[peak - 1]) > fabsf(
work[peak]) && (
work[peak - 1] *
work[peak] > 0)) {
316 }
else if (phase1 == 1) {
317 begin = peak - *
len / 2;
319 begin = (.997f - (2 - phase1) * .22
f) * *
len + .5f;
320 end = (.997f + (0 - phase1) * .22
f) * *
len + .5f;
321 begin = peak - (begin & ~3);
322 end = peak + 1 + ((
end + 3) & ~3);
331 for (
i = 0;
i < *
len;
i++) {
332 (*h)[
i] =
work[(begin + (phase > 50.f ? *
len - 1 -
i :
i) + work_len) & (work_len - 1)];
334 *post_len = phase > 50 ? peak - begin : begin + *
len - (peak + 1);
337 work_len, pi_wraps[work_len >> 1] /
M_PI, peak, peak_imp_sum, imp_peak,
338 work[imp_peak], *
len, *post_len, 100.
f - 100.
f * *post_len / (*
len - 1));
349 float Fn =
s->sample_rate * .5f;
351 int i, n, post_peak, longer;
356 if (
s->Fc0 >= Fn ||
s->Fc1 >= Fn) {
358 "filter frequency must be less than %d/2.\n",
s->sample_rate);
362 h[0] =
lpf(Fn,
s->Fc0,
s->tbw0, &
s->num_taps[0],
s->att, &
s->beta,
s->round);
363 h[1] =
lpf(Fn,
s->Fc1,
s->tbw1, &
s->num_taps[1],
s->att, &
s->beta,
s->round);
368 longer =
s->num_taps[1] >
s->num_taps[0];
369 n =
s->num_taps[longer];
372 for (
i = 0;
i <
s->num_taps[!longer];
i++)
373 h[longer][
i + (n -
s->num_taps[!longer]) / 2] +=
h[!longer][
i];
381 if (
s->phase != 50.f) {
395 for (
i = 0;
i < n;
i++)
396 s->coeffs[
i] =
h[longer][
i];
401 s->rdft =
s->irdft =
NULL;
413 s->rdft =
s->irdft =
NULL;
426 #define AF AV_OPT_FLAG_AUDIO_PARAM|AV_OPT_FLAG_FILTERING_PARAM
427 #define OFFSET(x) offsetof(SincContext, x)
432 {
"nb_samples",
"set the number of samples per requested frame",
OFFSET(nb_samples),
AV_OPT_TYPE_INT, {.i64=1024}, 1, INT_MAX,
AF },
433 {
"n",
"set the number of samples per requested frame",
OFFSET(nb_samples),
AV_OPT_TYPE_INT, {.i64=1024}, 1, INT_MAX,
AF },
440 {
"hptaps",
"set number of taps for high-pass filter",
OFFSET(num_taps[0]),
AV_OPT_TYPE_INT, {.i64=0}, 0, 32768,
AF },
441 {
"lptaps",
"set number of taps for low-pass filter",
OFFSET(num_taps[1]),
AV_OPT_TYPE_INT, {.i64=0}, 0, 32768,
AF },
449 .description =
NULL_IF_CONFIG_SMALL(
"Generate a sinc kaiser-windowed low-pass, high-pass, band-pass, or band-reject FIR coefficients."),
451 .priv_class = &sinc_class,