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bw_allpass2 done (untested) + fix doc bw_svf and more TODOs

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This commit is contained in:
Stefano D'Angelo 2022-12-13 22:41:18 +01:00
parent 2a482b77b0
commit aacd8236b4
3 changed files with 82 additions and 18 deletions
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2
TODO
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@ -16,6 +16,8 @@ code:
* polish examples (ranges, etc.)
* change name of vst3 template folders to something that doesn't look like a vst3 folder itself
* compute bit depth reduction only when input changes? (state)
* common smoothing policy (as control rate as possible?)
* avoid "force" in coeffs update by using inline functions?
build system:
* make makefiles handle paths with spaces etc

96
include/bw_allpass2.h
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@ -116,6 +116,14 @@ static inline void bw_allpass2_set_cutoff(bw_allpass2_coeffs *BW_RESTRICT coeffs
* Sets the cutoff frequency `value` (Hz) in `coeffs`.
*
* Default value: `1e3f`.
*
* #### bw_allpass2_set_Q()
* ```>>> */
static inline void bw_allpass2_set_Q(bw_allpass2_coeffs *BW_RESTRICT coeffs, float value);
/*! <<<```
* Sets the quality factor `value` in `coeffs`.
*
* Default value: `0.5f`.
* }}} */
/*** Implementation ***/
@ -130,20 +138,34 @@ struct _bw_allpass2_coeffs {
float t_k;
float t;
float X_k;
float kf;
float k;
float ks;
float X1_x;
float X2_X2_xz1_x1;
float X2_X1;
float X1_X2_xz1_x1;
float X1_VC1_xz1;
// Parameters
float cutoff;
float cutoff_prev;
float Q;
int param_changed;
};
struct _bw_allpass2_state {
float lp_z1;
float X_z1;
float VC1_z1;
float VC2_z1;
float X1_z1;
float X2_z1;
};
#define _BW_ALLPASS2_PARAM_CUTOFF 1
#define _BW_ALLPASS2_PARAM_Q (1<<1)
static inline void bw_allpass2_init(bw_allpass2_coeffs *BW_RESTRICT coeffs) {
coeffs->cutoff = 1e3f;
coeffs->Q = 0.5f;
}
static inline void bw_allpass2_set_sample_rate(bw_allpass2_coeffs *BW_RESTRICT coeffs, float sample_rate) {
@ -151,20 +173,38 @@ static inline void bw_allpass2_set_sample_rate(bw_allpass2_coeffs *BW_RESTRICT c
}
static inline void bw_allpass2_reset_coeffs(bw_allpass2_coeffs *BW_RESTRICT coeffs) {
coeffs->cutoff_prev = -1.f;
coeffs->param_changed = ~0;
bw_allpass2_update_coeffs_ctrl(coeffs);
}
static inline void bw_allpass2_reset_state(const bw_allpass2_coeffs *BW_RESTRICT coeffs, bw_allpass2_state *BW_RESTRICT state) {
state->lp_z1 = 0.f;
state->X_z1 = 0.f;
state->VC1_z1 = 0.f;
state->VC2_z1 = 0.f;
state->X1_z1 = 0.f;
state->X2_z1 = 0.f;
}
static inline void bw_allpass2_update_coeffs_ctrl(bw_allpass2_coeffs *BW_RESTRICT coeffs) {
if (coeffs->cutoff != coeffs->cutoff_prev) {
coeffs->t = bw_tanf_3(coeffs->t_k * coeffs->cutoff);
coeffs->X_k = bw_rcpf_2(1,f + coeffs->t);
coeffs->cutoff_prev = coeffs->cutoff;
if (coeffs->param_changed) {
if (coeffs->param_changed & _BW_ALLPASS2_PARAM_CUTOFF) {
coeffs->t = bw_tanf_3(coeffs->t_k * coeffs->cutoff);
coeffs->kf = coeffs->t * bw_rcpf_2(coeffs->cutoff);
}
if (coeffs->param_changed & _BW_ALLPASS2_PARAM_Q) {
const float Q2 = coeffs->Q + coeffs->Q;
const float Q2s = Q2 + Q2;
coeffs->k = Q2 * bw_rcpf_2(1.f + bw_sqrtf_2(1.f + Q2s + Q2s));
coeffs->ks = coeffs->k * coeffs->k;
coeffs->X1_x = 1.f - coeffs->ks - coeffs->ks;
}
const float kt = coeffs->k * coeffs->t;
const float kt1 = 1.f + kt;
const float X1_k = coeffs->cutoff * bw_rcpf_2(coeffs->t * kt1 + coeffs->k * (1.f - kt - kt));
coeffs->X2_X2_xz1_x1 = -coeffs->cutoff * coeffs->k * bw_rcpf_2(kt1);
coeffs->X2_X1 = coeffs->kf * coeffs->X2_X2_xz1_x1;
coeffs->X1_X2_xz1_x1 = 3.f * X1_k * coeffs->ks;
coeffs->X1_VC1_xz1 = X1_k * kt1;
coeffs->param_changed = 0;
}
}
@ -172,11 +212,20 @@ static inline void bw_allpass2_update_coeffs_audio(bw_allpass2_coeffs *BW_RESTRI
}
static inline float bw_allpass2_process1(const bw_allpass2_coeffs *BW_RESTRICT coeffs, bw_allpass2_state *BW_RESTRICT state, float x) {
const float X = coeffs->X_k * (x - state->lp_z1 - coeffs->t * state->X_z1);
const float lp = x - X;
state->X_z1 = X;
state->lp_z1 = lp;
return lp + lp - x;
const float VC2_xz1 = coeffs->kf * state->X2_z1 + state->VC2_z1;
const float VC1_xz1 = coeffs->kf * state->X1_z1 + state->VC1_z1;
const float X2_xz1_x1 = state->VC2_xz1 + state->VC1_xz1;
const float X2_xz1 = coeffs->X2_X2_xz1_x1 * X2_xz1_x1;
const float X1 = coeffs->X1_VC1_xz1 * (coeffs->X1_x * x - state->VC1_xz1) + coeffs->X1_X2_xz1_x1 * X2_xz1_x1;
const float X2 = X2_xz1 + coeffs->X2_X1 * X1;
const float VC1 = coeffs->kf * X1 + VC1_xz1;
const float VC2 = coeffs->kf * X2 + VC2_xz1;
const float y_x1 = VC1 + VC2;
state->VC1_z1 = VC1;
state->VC2_z1 = VC2;
state->X1_z1 = X1;
state->X2_z1 = X2;
return x - (y_x1 + y_x1);
}
static inline void bw_allpass2_process(bw_allpass2_coeffs *BW_RESTRICT coeffs, bw_allpass2_state *BW_RESTRICT state, const float *x, float *y, int n_samples) {
@ -186,9 +235,22 @@ static inline void bw_allpass2_process(bw_allpass2_coeffs *BW_RESTRICT coeffs, b
}
static inline void bw_allpass2_set_cutoff(bw_allpass2_coeffs *BW_RESTRICT coeffs, float value) {
coeffs->cutoff = value;
if (value != coeffs->cutoff) {
coeffs->cutoff = value;
coeffs->param_changed |= _BW_ALLPASS2_PARAM_CUTOFF;
}
}
static inline void bw_allpass2_set_Q(bw_allpass2_coeffs *BW_RESTRICT coeffs, float value) {
if (value != coeffs->Q) {
coeffs->Q = value;
coeffs->param_changed |= _BW_ALLPASS2_PARAM_Q;
}
}
#undef _BW_ALLPASS2_PARAM_CUTOFF
#undef _BW_ALLPASS2_PARAM_Q
#ifdef __cplusplus
}
#endif

2
include/bw_svf.h
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@ -132,7 +132,7 @@ static inline void bw_svf_set_cutoff(bw_svf_coeffs *BW_RESTRICT coeffs, float va
* ```>>> */
static inline void bw_svf_set_Q(bw_svf_coeffs *BW_RESTRICT coeffs, float value);
/*! <<<```
* Sets the quality factor to the given `value` (Hz) in `coeffs`.
* Sets the quality factor to the given `value` in `coeffs`.
*
* `value` must be equal or bigger than `0.5f`.
*