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fixed and improved bw_src_int implementation

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This commit is contained in:
Stefano D'Angelo 2023-09-13 16:55:06 +02:00
parent a3f42c8c57
commit 7d6409772f
1 changed files with 35 additions and 28 deletions
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63
include/bw_src_int.h
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@ -35,6 +35,7 @@
* <ul>
* <li>Version <strong>1.0.0</strong>:
* <ul>
* <li><code>Fixed frequency response and improved speed.</code></li>
* <li><code>bw_src_int_lim_process()</code> and
* <code>bw_src_int_lim_process_multi()</code> now use
* <code>size_t</code> to count samples and channels.</li>
@ -160,13 +161,11 @@ extern "C" {
struct bw_src_int_coeffs {
int ratio;
float a1;
float a2;
float a3;
float a4;
float b0;
float b1;
float b2;
float ma1;
float ma2;
float ma3;
float ma4;
};
struct bw_src_int_state {
@ -185,28 +184,27 @@ static inline void bw_src_int_init(bw_src_int_coeffs *BW_RESTRICT coeffs, int ra
const float T2 = T * T;
const float k = 1.f / (T * (T * (T * (T + 2.613125929752753f) + 3.414213562373095f) + 2.613125929752753f) + 1.f);
coeffs->b0 = k * T2 * T2;
coeffs->b1 = 4.f * coeffs->b0;
coeffs->b2 = 6.f * coeffs->b0;
coeffs->a1 = k * (T * (T2 * (4.f * T + 5.226251859505504f) - 5.226251859505504f) - 4.f);
coeffs->a2 = k * (T2 * (6.f * T2 - 6.82842712474619f) + 6.f);
coeffs->a3 = k * (T * (T2 * (4.f * T - 5.226251859505504f) + 5.226251859505504f) - 4.f);
coeffs->a4 = k * (T * (T * (T * (T - 2.613125929752753f) + 3.414213562373095f) - 2.613125929752753f) + 1.f);
coeffs->ma1 = k * (T * (T2 * (-5.226251859505504f - 4.f * T) + 5.226251859505504f) + 4.f);
coeffs->ma2 = k * ((6.82842712474619f - 6.f * T2) * T2 - 6.f);
coeffs->ma3 = k * (T * (T2 * (5.226251859505504f - 4.f * T) - 5.226251859505504f) + 4.f);
coeffs->ma4 = k * (T * (T * ((2.613125929752753f - T) * T - 3.414213562373095f) + 2.613125929752753f) - 1.f);
}
static inline void bw_src_int_reset_state(const bw_src_int_coeffs *BW_RESTRICT coeffs, bw_src_int_state *BW_RESTRICT state, float x_0) {
if (coeffs->ratio < 0) {
// DF-II
state->z1 = x_0 / (1.f + coeffs->a1 + coeffs->a2 + coeffs->a3 + coeffs->a4);
state->z1 = x_0 / (1.f - coeffs->ma1 - coeffs->ma2 - coeffs->ma3 - coeffs->ma4);
state->z2 = state->z1;
state->z3 = state->z2;
state->z4 = state->z3;
state->i = 0;
} else {
// TDF-II
state->z4 = (coeffs->b0 - coeffs->a4) * x_0;
state->z3 = (coeffs->b1 - coeffs->a3) * x_0 + state->z4;
state->z2 = (coeffs->b2 - coeffs->a2) * x_0 + state->z3;
state->z1 = (coeffs->b1 - coeffs->a1) * x_0 + state->z2;
const float k = 4.f * coeffs->b0;
state->z4 = (coeffs->b0 + coeffs->ma4) * x_0;
state->z3 = (k + coeffs->ma3) * x_0 + state->z4;
state->z2 = (6.f * coeffs->b0 + coeffs->ma2) * x_0 + state->z3;
state->z1 = (k + coeffs->ma1) * x_0 + state->z2;
}
}
@ -215,10 +213,10 @@ static inline size_t bw_src_int_process(const bw_src_int_coeffs *BW_RESTRICT coe
if (coeffs->ratio < 0) {
for (size_t i = 0; i < n_in_samples; i++) {
// DF-II
const float z0 = x[i] - coeffs->a1 * state->z1 - coeffs->a2 * state->z2 - coeffs->a3 * state->z3 - coeffs->a4 * state->z4;
const float z0 = x[i] + coeffs->ma1 * state->z1 + coeffs->ma2 * state->z2 + coeffs->ma3 * state->z3 + coeffs->ma4 * state->z4;
if (!state->i) {
state->i = -coeffs->ratio;
y[n] = coeffs->b0 * (z0 + state->z4) + coeffs->b1 * (state->z1 + state->z3) + coeffs->b2 * state->z2;
y[n] = coeffs->b0 * (z0 + state->z4 + 4.f * (state->z1 + state->z3) + 6.f * state->z2);
n++;
}
state->i--;
@ -230,15 +228,24 @@ static inline size_t bw_src_int_process(const bw_src_int_coeffs *BW_RESTRICT coe
} else {
for (size_t i = 0; i < n_in_samples; i++) {
// TDF-II
const float v0 = coeffs->b0 * x[i];
const float v1 = coeffs->b1 * x[i];
const float v2 = coeffs->b2 * x[i];
for (int j = 0; j < coeffs->ratio; j++) {
y[n] = v0 + state->z1;
state->z1 = v1 - coeffs->a1 * y[n] + state->z2;
state->z2 = v2 - coeffs->a2 * y[n] + state->z3;
state->z3 = v1 - coeffs->a3 * y[n] + state->z4;
state->z4 = v0 - coeffs->a4 * y[n];
const float in = coeffs->ratio * x[i];
const float v0 = coeffs->b0 * in;
const float v1 = 4.f * v0;
const float v2 = 6.f * v0;
float o = v0 + state->z1;
state->z1 = v1 + coeffs->ma1 * o + state->z2;
state->z2 = v2 + coeffs->ma2 * o + state->z3;
state->z3 = v1 + coeffs->ma3 * o + state->z4;
state->z4 = v0 + coeffs->ma4 * o;
y[n] = o;
n++;
for (int j = 1; j < coeffs->ratio; j++) {
o = state->z1;
state->z1 = coeffs->ma1 * o + state->z2;
state->z2 = coeffs->ma2 * o + state->z3;
state->z3 = coeffs->ma3 * o + state->z4;
state->z4 = coeffs->ma4 * o;
y[n] = o;
n++;
}
}