280 lines
8.2 KiB
C++
280 lines
8.2 KiB
C++
/*
|
|
* Brickworks
|
|
*
|
|
* Copyright (C) 2022, 2023 Orastron Srl unipersonale
|
|
*
|
|
* Brickworks is free software: you can redistribute it and/or modify
|
|
* it under the terms of the GNU General Public License as published by
|
|
* the Free Software Foundation, version 3 of the License.
|
|
*
|
|
* Brickworks is distributed in the hope that it will be useful,
|
|
* but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|
* GNU General Public License for more details.
|
|
*
|
|
* You should have received a copy of the GNU General Public License
|
|
* along with Brickworks. If not, see <http://www.gnu.org/licenses/>.
|
|
*
|
|
* File author: Stefano D'Angelo
|
|
*/
|
|
|
|
/*!
|
|
* module_type {{{ dsp }}}
|
|
* version {{{ 1.0.0 }}}
|
|
* requires {{{ bw_common bw_math }}}
|
|
* description {{{
|
|
* Sample rate reducer.
|
|
*
|
|
* This is purely an audio effect, it doesn't actually produce an output
|
|
* signal at a lower sample rate. The algorithm is deliberately crude to
|
|
* obtain the characteristic aliasing due to lo-fi downsampling.
|
|
* }}}
|
|
* changelog {{{
|
|
* <ul>
|
|
* <li>Version <strong>1.0.0</strong>:
|
|
* <ul>
|
|
* <li><code>bw_sr_reduce_lim_process()</code> and
|
|
* <code>bw_sr_reduce_lim_process_multi()</code> now use
|
|
* <code>size_t</code> to count samples and channels.</li>
|
|
* <li>Added more <code>const</code> and <code>BW_RESTRICT</code>
|
|
* specifiers to input arguments and implementation.</li>
|
|
* <li>Moved C++ code to C header.</li>
|
|
* <li>Added overloaded C++ <code>process()</code> function taking
|
|
* C-style arrays as arguments.</li>
|
|
* <li>Removed usage of reserved identifiers.</li>
|
|
* </ul>
|
|
* </li>
|
|
* <li>Version <strong>0.6.0</strong>:
|
|
* <ul>
|
|
* <li>Removed dependency on bw_config.</li>
|
|
* </ul>
|
|
* </li>
|
|
* <li>Version <strong>0.5.0</strong>:
|
|
* <ul>
|
|
* <li>Added <code>bw_sr_reduce_process_multi()</code>.</li>
|
|
* <li>Added C++ wrapper.</li>
|
|
* </ul>
|
|
* </li>
|
|
* <li>Version <strong>0.4.0</strong>:
|
|
* <ul>
|
|
* <li>Fixed unused parameter warnings.</li>
|
|
* </ul>
|
|
* </li>
|
|
* <li>Version <strong>0.3.0</strong>:
|
|
* <ul>
|
|
* <li>First release.</li>
|
|
* </ul>
|
|
* </li>
|
|
* </ul>
|
|
* }}}
|
|
*/
|
|
|
|
#ifndef BW_SR_REDUCE_H
|
|
#define BW_SR_REDUCE_H
|
|
|
|
#include <bw_common.h>
|
|
|
|
#ifdef __cplusplus
|
|
extern "C" {
|
|
#endif
|
|
|
|
/*! api {{{
|
|
* #### bw_sr_reduce_coeffs
|
|
* ```>>> */
|
|
typedef struct bw_sr_reduce_coeffs bw_sr_reduce_coeffs;
|
|
/*! <<<```
|
|
* Coefficients and related.
|
|
*
|
|
* #### bw_sr_reduce_state
|
|
* ```>>> */
|
|
typedef struct bw_sr_reduce_state bw_sr_reduce_state;
|
|
/*! <<<```
|
|
* Internal state and related.
|
|
*
|
|
* #### bw_sr_reduce_init()
|
|
* ```>>> */
|
|
static inline void bw_sr_reduce_init(bw_sr_reduce_coeffs *BW_RESTRICT coeffs);
|
|
/*! <<<```
|
|
* Initializes input parameter values in `coeffs`.
|
|
*
|
|
* #### bw_sr_reduce_reset_state()
|
|
* ```>>> */
|
|
static inline void bw_sr_reduce_reset_state(const bw_sr_reduce_coeffs *BW_RESTRICT coeffs, bw_sr_reduce_state *BW_RESTRICT state);
|
|
/*! <<<```
|
|
* Resets the given `state` to its initial values using the given `coeffs`.
|
|
*
|
|
* #### bw_sr_reduce_process1()
|
|
* ```>>> */
|
|
static inline float bw_sr_reduce_process1(const bw_sr_reduce_coeffs *BW_RESTRICT coeffs, bw_sr_reduce_state *BW_RESTRICT state, float x);
|
|
/*! <<<```
|
|
* Processes one input sample `x` using `coeffs`, while using and updating
|
|
* `state`. Returns the corresponding output sample.
|
|
*
|
|
* #### bw_sr_reduce_process()
|
|
* ```>>> */
|
|
static inline void bw_sr_reduce_process(bw_sr_reduce_coeffs *BW_RESTRICT coeffs, bw_sr_reduce_state *BW_RESTRICT state, const float *x, float *y, size_t n_samples);
|
|
/*! <<<```
|
|
* Processes the first `n_samples` of the input buffer `x` and fills the
|
|
* first `n_samples` of the output buffer `y`, while using `coeffs` and
|
|
* both using and updating `state` (control and audio rate).
|
|
*
|
|
* #### bw_sr_reduce_process_multi()
|
|
* ```>>> */
|
|
static inline void bw_sr_reduce_process_multi(bw_sr_reduce_coeffs *BW_RESTRICT coeffs, bw_sr_reduce_state *BW_RESTRICT const *BW_RESTRICT state, const float * const *x, float * const *y, size_t n_channels, size_t n_samples);
|
|
/*! <<<```
|
|
* Processes the first `n_samples` of the `n_channels` input buffers `x` and
|
|
* fills the first `n_samples` of the `n_channels` output buffers `y`, while
|
|
* using the common `coeffs` and both using and updating each of the
|
|
* `n_channels` `state`s.
|
|
*
|
|
* #### bw_sr_reduce_set_ratio()
|
|
* ```>>> */
|
|
static inline void bw_sr_reduce_set_ratio(bw_sr_reduce_coeffs *BW_RESTRICT coeffs, float value);
|
|
/*! <<<```
|
|
* Sets the output to input sample rate ratio in `coeffs`.
|
|
*
|
|
* Valid input range: [`0.f`, `1.f`].
|
|
*
|
|
* Default value: `1.f`.
|
|
* }}} */
|
|
|
|
#ifdef __cplusplus
|
|
}
|
|
#endif
|
|
|
|
/*** Implementation ***/
|
|
|
|
/* WARNING: This part of the file is not part of the public API. Its content may
|
|
* change at any time in future versions. Please, do not use it directly. */
|
|
|
|
#include <bw_math.h>
|
|
|
|
#ifdef __cplusplus
|
|
extern "C" {
|
|
#endif
|
|
|
|
struct bw_sr_reduce_coeffs {
|
|
// Parameters
|
|
float ratio;
|
|
};
|
|
|
|
struct bw_sr_reduce_state {
|
|
float phase;
|
|
float y_z1;
|
|
};
|
|
|
|
static inline void bw_sr_reduce_init(bw_sr_reduce_coeffs *BW_RESTRICT coeffs) {
|
|
coeffs->ratio = 1.f;
|
|
}
|
|
|
|
static inline void bw_sr_reduce_reset_state(const bw_sr_reduce_coeffs *BW_RESTRICT coeffs, bw_sr_reduce_state *BW_RESTRICT state) {
|
|
(void)coeffs;
|
|
state->phase = 1.f;
|
|
}
|
|
|
|
static inline float bw_sr_reduce_process1(const bw_sr_reduce_coeffs *BW_RESTRICT coeffs, bw_sr_reduce_state *BW_RESTRICT state, float x) {
|
|
state->phase += coeffs->ratio;
|
|
if (state->phase >= 1.f) {
|
|
state->y_z1 = x;
|
|
state->phase -= bw_floorf(state->phase);
|
|
}
|
|
return state->y_z1;
|
|
}
|
|
|
|
static inline void bw_sr_reduce_process(bw_sr_reduce_coeffs *BW_RESTRICT coeffs, bw_sr_reduce_state *BW_RESTRICT state, const float *x, float *y, size_t n_samples) {
|
|
for (size_t i = 0; i < n_samples; i++)
|
|
y[i] = bw_sr_reduce_process1(coeffs, state, x[i]);
|
|
}
|
|
|
|
static inline void bw_sr_reduce_process_multi(bw_sr_reduce_coeffs *BW_RESTRICT coeffs, bw_sr_reduce_state *BW_RESTRICT const *BW_RESTRICT state, const float * const *x, float * const *y, size_t n_channels, size_t n_samples) {
|
|
for (size_t i = 0; i < n_channels; i++)
|
|
bw_sr_reduce_process(coeffs, state[i], x[i], y[i], n_samples);
|
|
}
|
|
|
|
static inline void bw_sr_reduce_set_ratio(bw_sr_reduce_coeffs *BW_RESTRICT coeffs, float value) {
|
|
coeffs->ratio = value;
|
|
}
|
|
|
|
#ifdef __cplusplus
|
|
}
|
|
|
|
#include <array>
|
|
|
|
namespace Brickworks {
|
|
|
|
/*** Public C++ API ***/
|
|
|
|
/*! api_cpp {{{
|
|
* ##### Brickworks::SRReduce
|
|
* ```>>> */
|
|
template<size_t N_CHANNELS>
|
|
class SRReduce {
|
|
public:
|
|
SRReduce();
|
|
|
|
void reset();
|
|
void process(
|
|
const float * const *x,
|
|
float * const *y,
|
|
size_t nSamples);
|
|
void process(
|
|
std::array<const float *, N_CHANNELS> x,
|
|
std::array<float *, N_CHANNELS> y,
|
|
size_t nSamples);
|
|
|
|
void setRatio(float value);
|
|
/*! <<<...
|
|
* }
|
|
* ```
|
|
* }}} */
|
|
|
|
/*** Implementation ***/
|
|
|
|
/* WARNING: This part of the file is not part of the public API. Its content may
|
|
* change at any time in future versions. Please, do not use it directly. */
|
|
|
|
private:
|
|
bw_sr_reduce_coeffs coeffs;
|
|
bw_sr_reduce_state states[N_CHANNELS];
|
|
bw_sr_reduce_state *BW_RESTRICT statesP[N_CHANNELS];
|
|
};
|
|
|
|
template<size_t N_CHANNELS>
|
|
inline SRReduce<N_CHANNELS>::SRReduce() {
|
|
bw_sr_reduce_init(&coeffs);
|
|
for (size_t i = 0; i < N_CHANNELS; i++)
|
|
statesP[i] = states + i;
|
|
}
|
|
|
|
template<size_t N_CHANNELS>
|
|
inline void SRReduce<N_CHANNELS>::reset() {
|
|
for (size_t i = 0; i < N_CHANNELS; i++)
|
|
bw_sr_reduce_reset_state(&coeffs, states + i);
|
|
}
|
|
|
|
template<size_t N_CHANNELS>
|
|
inline void SRReduce<N_CHANNELS>::process(
|
|
const float * const *x,
|
|
float * const *y,
|
|
size_t nSamples) {
|
|
bw_sr_reduce_process_multi(&coeffs, statesP, x, y, N_CHANNELS, nSamples);
|
|
}
|
|
|
|
template<size_t N_CHANNELS>
|
|
inline void SRReduce<N_CHANNELS>::process(
|
|
std::array<const float *, N_CHANNELS> x,
|
|
std::array<float *, N_CHANNELS> y,
|
|
size_t nSamples) {
|
|
process(x.data(), y.data(), nSamples);
|
|
}
|
|
|
|
template<size_t N_CHANNELS>
|
|
inline void SRReduce<N_CHANNELS>::setRatio(float value) {
|
|
bw_sr_reduce_set_ratio(&coeffs, value);
|
|
}
|
|
|
|
}
|
|
#endif
|
|
|
|
#endif
|