/*
* Brickworks
*
* Copyright (C) 2022-2024 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 {{{ 1.2.0 }}}
* requires {{{ bw_common bw_math }}}
* description {{{
* Bit depth reducer with input gate.
*
* This is purely an audio effect, it doesn't actually produce an output
* signal with a different encoding. The algorithm is deliberately crude to
* obtain the characteristic noise due to lo-fi A/D quantization.
* }}}
* changelog {{{
* <ul>
* <li>Version <strong>1.2.0</strong>:
* <ul>
* <li>Added gate parameter.</li>
* <li>Added debugging checks from <code>bw_bd_reduce_process()</code>
* to <code>bw_bd_reduce_process_multi()</code>.</li>
* <li>Added debugging checks in
* <code>bw_bd_reduce_process_multi()</code> to ensure that buffers
* used for both input and output appear at the same channel
* indices.</li>
* </ul>
* </li>
* <li>Version <strong>1.1.0</strong>:
* <ul>
* <li>Added silence_dc parameter.</li>
* <li>Now using <code>BW_NULL</code> and
* <code>BW_CXX_NO_ARRAY</code>.</li>
* </ul>
* </li>
* <li>Version <strong>1.0.0</strong>:
* <ul>
* <li>Added <code>bw_bd_reduce_set_sample_rate()</code>.</li>
* <li><code>bw_bd_reduce_process()</code> and
* <code>bw_bd_reduce_process_multi()</code> now use
* <code>size_t</code> to count samples and channels.</li>
* <li>Added more <code>const</code> specifiers to input
* arguments.</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>
* <li>Clearly specified parameter validity ranges.</li>
* <li>Added debugging code.</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_bd_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_BD_REDUCE_H
#define BW_BD_REDUCE_H
#include <bw_common.h>
#ifdef __cplusplus
extern "C" {
#endif
/*! api {{{
* #### bw_bd_reduce_coeffs
* ```>>> */
typedef struct bw_bd_reduce_coeffs bw_bd_reduce_coeffs;
/*! <<<```
* Coefficients and related.
*
* #### bw_bd_reduce_init()
* ```>>> */
static inline void bw_bd_reduce_init(
bw_bd_reduce_coeffs * BW_RESTRICT coeffs);
/*! <<<```
* Initializes input parameter values in `coeffs`.
*
* #### bw_bw_reduce_set_sample_rate()
* ```>>> */
static inline void bw_bd_reduce_set_sample_rate(
bw_bd_reduce_coeffs * BW_RESTRICT coeffs,
float sample_rate);
/*! <<<```
* Sets the `sample_rate` (Hz) value in `coeffs`.
*
* #### bw_bd_reduce_reset_coeffs()
* ```>>> */
static inline void bw_bd_reduce_reset_coeffs(
bw_bd_reduce_coeffs * BW_RESTRICT coeffs);
/*! <<<```
* Resets coefficients in `coeffs` to assume their target values.
*
* #### bw_bd_reduce_update_coeffs_ctrl()
* ```>>> */
static inline void bw_bd_reduce_update_coeffs_ctrl(
bw_bd_reduce_coeffs * BW_RESTRICT coeffs);
/*! <<<```
* Triggers control-rate update of coefficients in `coeffs`.
*
* #### bw_bd_reduce_update_coeffs_audio()
* ```>>> */
static inline void bw_bd_reduce_update_coeffs_audio(
bw_bd_reduce_coeffs * BW_RESTRICT coeffs);
/*! <<<```
* Triggers audio-rate update of coefficients in `coeffs`.
*
* #### bw_bd_reduce_process1()
* ```>>> */
static inline float bw_bd_reduce_process1(
const bw_bd_reduce_coeffs * BW_RESTRICT coeffs,
float x);
/*! <<<```
* Processes one input sample `x` using `coeffs`. Returns the corresponding
* output sample.
*
* #### bw_bd_reduce_process()
* ```>>> */
static inline void bw_bd_reduce_process(
bw_bd_reduce_coeffs * BW_RESTRICT coeffs,
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 and updating
* `coeffs` (control and audio rate).
*
* #### bw_bd_reduce_process_multi()
* ```>>> */
static inline void bw_bd_reduce_process_multi(
bw_bd_reduce_coeffs * BW_RESTRICT coeffs,
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 and updating the common `coeffs` (control and audio rate).
*
* #### bw_bd_reduce_set_bit_depth()
* ```>>> */
static inline void bw_bd_reduce_set_bit_depth(
bw_bd_reduce_coeffs * BW_RESTRICT coeffs,
char value);
/*! <<<```
* Sets the output bit depth `value` in `coeffs`.
*
* Valid range: [`1`, `64`].
*
* Default value: `16`.
*
* #### bw_bd_reduce_set_silence_dc()
* ```>>> */
static inline void bw_bd_reduce_set_silence_dc(
bw_bd_reduce_coeffs * BW_RESTRICT coeffs,
char value);
/*! <<<```
* Sets whether the output value corresponding to silence has null dc
* (`value` `0`) or not (non-`0`) in `coeffs`.
*
* Default value: non-`0` (non-null dc).
*
* #### bw_bd_reduce_set_gate_lin()
* ```>>> */
static inline void bw_bd_reduce_set_gate_lin(
bw_bd_reduce_coeffs * BW_RESTRICT coeffs,
float value);
/*! <<<```
* Sets the input gate threshold `value` (linear) in `coeffs`.
*
* Valid range: [`0.f`, `1.f`].
*
* Default value: `0.f`.
*
* #### bw_bd_reduce_set_gate_dBFS()
* ```>>> */
static inline void bw_bd_reduce_set_gate_dBFS(
bw_bd_reduce_coeffs * BW_RESTRICT coeffs,
float value);
/*! <<<```
* Sets the input gate threshold `value` (dBFS) in `coeffs`.
*
* Valid range: [`-INFINITY`, `0.f`].
*
* Default value: `-INFINITY`.
*
* #### bw_bd_reduce_coeffs_is_valid()
* ```>>> */
static inline char bw_bd_reduce_coeffs_is_valid(
const bw_bd_reduce_coeffs * BW_RESTRICT coeffs);
/*! <<<```
* Tries to determine whether `coeffs` is valid and returns non-`0` if it
* seems to be the case and `0` if it is certainly not. False positives are
* possible, false negatives are not.
*
* `coeffs` must at least point to a readable memory block of size greater
* than or equal to that of `bw_bd_reduce_coeffs`.
* }}} */
#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
#ifdef BW_DEBUG_DEEP
enum bw_bd_reduce_coeffs_state {
bw_bd_reduce_coeffs_state_invalid,
bw_bd_reduce_coeffs_state_init,
bw_bd_reduce_coeffs_state_set_sample_rate,
bw_bd_reduce_coeffs_state_reset_coeffs
};
#endif
struct bw_bd_reduce_coeffs {
#ifdef BW_DEBUG_DEEP
uint32_t hash;
enum bw_bd_reduce_coeffs_state state;
#endif
// Coefficients
float ki;
float k;
float ko;
float max;
float gate;
// Parameters
char bit_depth;
char bit_depth_prev;
};
static inline void bw_bd_reduce_init(
bw_bd_reduce_coeffs * BW_RESTRICT coeffs) {
BW_ASSERT(coeffs != BW_NULL);
coeffs->bit_depth = 16;
coeffs->ko = 0.5f;
coeffs->gate = 0.f;
#ifdef BW_DEBUG_DEEP
coeffs->hash = bw_hash_sdbm("bw_bd_reduce_coeffs");
coeffs->state = bw_bd_reduce_coeffs_state_init;
#endif
BW_ASSERT_DEEP(bw_bd_reduce_coeffs_is_valid(coeffs));
BW_ASSERT_DEEP(coeffs->state == bw_bd_reduce_coeffs_state_init);
}
static inline void bw_bd_reduce_set_sample_rate(
bw_bd_reduce_coeffs * BW_RESTRICT coeffs,
float sample_rate) {
BW_ASSERT(coeffs != BW_NULL);
BW_ASSERT_DEEP(bw_bd_reduce_coeffs_is_valid(coeffs));
BW_ASSERT_DEEP(coeffs->state >= bw_bd_reduce_coeffs_state_init);
BW_ASSERT(bw_is_finite(sample_rate) && sample_rate > 0.f);
(void)coeffs;
(void)sample_rate;
#ifdef BW_DEBUG_DEEP
coeffs->state = bw_bd_reduce_coeffs_state_set_sample_rate;
#endif
BW_ASSERT_DEEP(bw_bd_reduce_coeffs_is_valid(coeffs));
BW_ASSERT_DEEP(coeffs->state == bw_bd_reduce_coeffs_state_set_sample_rate);
}
static inline void bw_bd_reduce_do_update_coeffs_ctrl(
bw_bd_reduce_coeffs * BW_RESTRICT coeffs) {
if (coeffs->bit_depth_prev != coeffs->bit_depth) {
coeffs->k = bw_pow2f(coeffs->bit_depth - 1);
coeffs->ki = bw_rcpf(coeffs->k);
coeffs->max = 1.f - 0.5f * coeffs->ki;
coeffs->bit_depth_prev = coeffs->bit_depth;
}
}
static inline void bw_bd_reduce_reset_coeffs(
bw_bd_reduce_coeffs * BW_RESTRICT coeffs) {
BW_ASSERT(coeffs != BW_NULL);
BW_ASSERT_DEEP(bw_bd_reduce_coeffs_is_valid(coeffs));
BW_ASSERT_DEEP(coeffs->state >= bw_bd_reduce_coeffs_state_set_sample_rate);
coeffs->bit_depth_prev = 0;
bw_bd_reduce_do_update_coeffs_ctrl(coeffs);
#ifdef BW_DEBUG_DEEP
coeffs->state = bw_bd_reduce_coeffs_state_reset_coeffs;
#endif
BW_ASSERT_DEEP(bw_bd_reduce_coeffs_is_valid(coeffs));
BW_ASSERT_DEEP(coeffs->state == bw_bd_reduce_coeffs_state_reset_coeffs);
}
static inline void bw_bd_reduce_update_coeffs_ctrl(
bw_bd_reduce_coeffs * BW_RESTRICT coeffs) {
BW_ASSERT(coeffs != BW_NULL);
BW_ASSERT_DEEP(bw_bd_reduce_coeffs_is_valid(coeffs));
BW_ASSERT_DEEP(coeffs->state >= bw_bd_reduce_coeffs_state_reset_coeffs);
bw_bd_reduce_do_update_coeffs_ctrl(coeffs);
BW_ASSERT_DEEP(bw_bd_reduce_coeffs_is_valid(coeffs));
BW_ASSERT_DEEP(coeffs->state >= bw_bd_reduce_coeffs_state_reset_coeffs);
}
static inline void bw_bd_reduce_update_coeffs_audio(
bw_bd_reduce_coeffs * BW_RESTRICT coeffs) {
BW_ASSERT(coeffs != BW_NULL);
BW_ASSERT_DEEP(bw_bd_reduce_coeffs_is_valid(coeffs));
BW_ASSERT_DEEP(coeffs->state >= bw_bd_reduce_coeffs_state_reset_coeffs);
(void)coeffs;
}
static inline float bw_bd_reduce_process1(
const bw_bd_reduce_coeffs * BW_RESTRICT coeffs,
float x) {
BW_ASSERT(coeffs != BW_NULL);
BW_ASSERT_DEEP(bw_bd_reduce_coeffs_is_valid(coeffs));
BW_ASSERT_DEEP(coeffs->state >= bw_bd_reduce_coeffs_state_reset_coeffs);
BW_ASSERT(bw_is_finite(x));
x = bw_absf(x) < coeffs->gate ? 0.f : x;
const float y = coeffs->ki * (bw_floorf(coeffs->k * bw_clipf(x, -coeffs->max, coeffs->max)) + coeffs->ko);
BW_ASSERT_DEEP(bw_bd_reduce_coeffs_is_valid(coeffs));
BW_ASSERT_DEEP(coeffs->state >= bw_bd_reduce_coeffs_state_reset_coeffs);
BW_ASSERT(bw_is_finite(y));
return y;
}
static inline void bw_bd_reduce_process(
bw_bd_reduce_coeffs * BW_RESTRICT coeffs,
const float * x,
float * y,
size_t n_samples) {
BW_ASSERT(coeffs != BW_NULL);
BW_ASSERT_DEEP(bw_bd_reduce_coeffs_is_valid(coeffs));
BW_ASSERT_DEEP(coeffs->state >= bw_bd_reduce_coeffs_state_reset_coeffs);
BW_ASSERT(x != BW_NULL);
BW_ASSERT_DEEP(bw_has_only_finite(x, n_samples));
BW_ASSERT(y != BW_NULL);
bw_bd_reduce_update_coeffs_ctrl(coeffs);
for (size_t i = 0; i < n_samples; i++)
y[i] = bw_bd_reduce_process1(coeffs, x[i]);
BW_ASSERT_DEEP(bw_bd_reduce_coeffs_is_valid(coeffs));
BW_ASSERT_DEEP(coeffs->state >= bw_bd_reduce_coeffs_state_reset_coeffs);
BW_ASSERT_DEEP(bw_has_only_finite(y, n_samples));
}
static inline void bw_bd_reduce_process_multi(
bw_bd_reduce_coeffs * BW_RESTRICT coeffs,
const float * const * x,
float * const * y,
size_t n_channels,
size_t n_samples) {
BW_ASSERT(coeffs != BW_NULL);
BW_ASSERT_DEEP(bw_bd_reduce_coeffs_is_valid(coeffs));
BW_ASSERT_DEEP(coeffs->state >= bw_bd_reduce_coeffs_state_reset_coeffs);
BW_ASSERT(x != BW_NULL);
BW_ASSERT(y != BW_NULL);
#ifndef BW_NO_DEBUG
for (size_t i = 0; i < n_channels; i++) {
BW_ASSERT(x[i] != BW_NULL);
BW_ASSERT_DEEP(bw_has_only_finite(x[i], n_samples));
BW_ASSERT(y[i] != BW_NULL);
}
for (size_t i = 0; i < n_channels; i++)
for (size_t j = i + 1; j < n_channels; j++)
BW_ASSERT(y[i] != y[j]);
for (size_t i = 0; i < n_channels; i++)
for (size_t j = 0; j < n_channels; j++)
BW_ASSERT(i == j || x[i] != y[j]);
#endif
bw_bd_reduce_update_coeffs_ctrl(coeffs);
for (size_t i = 0; i < n_samples; i++)
for (size_t j = 0; j < n_channels; j++)
y[j][i] = bw_bd_reduce_process1(coeffs, x[j][i]);
BW_ASSERT_DEEP(bw_bd_reduce_coeffs_is_valid(coeffs));
BW_ASSERT_DEEP(coeffs->state >= bw_bd_reduce_coeffs_state_reset_coeffs);
#ifndef BW_NO_DEBUG
for (size_t i = 0; i < n_channels; i++)
BW_ASSERT_DEEP(bw_has_only_finite(y[i], n_samples));
#endif
}
static inline void bw_bd_reduce_set_bit_depth(
bw_bd_reduce_coeffs * BW_RESTRICT coeffs,
char value) {
BW_ASSERT(coeffs != BW_NULL);
BW_ASSERT_DEEP(bw_bd_reduce_coeffs_is_valid(coeffs));
BW_ASSERT_DEEP(coeffs->state >= bw_bd_reduce_coeffs_state_init);
BW_ASSERT(value >= 1 && value <= 64);
coeffs->bit_depth = value;
BW_ASSERT_DEEP(bw_bd_reduce_coeffs_is_valid(coeffs));
BW_ASSERT_DEEP(coeffs->state >= bw_bd_reduce_coeffs_state_init);
}
static inline void bw_bd_reduce_set_silence_dc(
bw_bd_reduce_coeffs * BW_RESTRICT coeffs,
char value) {
BW_ASSERT(coeffs != BW_NULL);
BW_ASSERT_DEEP(bw_bd_reduce_coeffs_is_valid(coeffs));
BW_ASSERT_DEEP(coeffs->state >= bw_bd_reduce_coeffs_state_init);
coeffs->ko = value ? 0.5f : 0.f;
BW_ASSERT_DEEP(bw_bd_reduce_coeffs_is_valid(coeffs));
BW_ASSERT_DEEP(coeffs->state >= bw_bd_reduce_coeffs_state_init);
}
static inline void bw_bd_reduce_set_gate_lin(
bw_bd_reduce_coeffs * BW_RESTRICT coeffs,
float value) {
BW_ASSERT(coeffs != BW_NULL);
BW_ASSERT_DEEP(bw_bd_reduce_coeffs_is_valid(coeffs));
BW_ASSERT_DEEP(coeffs->state >= bw_bd_reduce_coeffs_state_init);
BW_ASSERT(bw_is_finite(value));
BW_ASSERT(value >= 0.f && value <= 1.f);
coeffs->gate = value;
BW_ASSERT_DEEP(bw_bd_reduce_coeffs_is_valid(coeffs));
BW_ASSERT_DEEP(coeffs->state >= bw_bd_reduce_coeffs_state_init);
}
static inline void bw_bd_reduce_set_gate_dBFS(
bw_bd_reduce_coeffs * BW_RESTRICT coeffs,
float value) {
BW_ASSERT(coeffs != BW_NULL);
BW_ASSERT_DEEP(bw_bd_reduce_coeffs_is_valid(coeffs));
BW_ASSERT_DEEP(coeffs->state >= bw_bd_reduce_coeffs_state_init);
BW_ASSERT(bw_is_finite(value));
BW_ASSERT(value <= 0.f);
coeffs->gate = bw_dB2linf(value);
BW_ASSERT_DEEP(bw_bd_reduce_coeffs_is_valid(coeffs));
BW_ASSERT_DEEP(coeffs->state >= bw_bd_reduce_coeffs_state_init);
}
static inline char bw_bd_reduce_coeffs_is_valid(
const bw_bd_reduce_coeffs * BW_RESTRICT coeffs) {
BW_ASSERT(coeffs != BW_NULL);
#ifdef BW_DEBUG_DEEP
if (coeffs->hash != bw_hash_sdbm("bw_bd_reduce_coeffs"))
return 0;
if (coeffs->state < bw_bd_reduce_coeffs_state_init || coeffs->state > bw_bd_reduce_coeffs_state_reset_coeffs)
return 0;
#endif
if (coeffs->bit_depth < 1 || coeffs->bit_depth > 64)
return 0;
#ifdef BW_DEBUG_DEEP
if (coeffs->state >= bw_bd_reduce_coeffs_state_reset_coeffs) {
if (coeffs->bit_depth_prev < 1 || coeffs->bit_depth_prev > 64)
return 0;
if (!bw_is_finite(coeffs->ki) || coeffs->ki <= 0.f)
return 0;
if (!bw_is_finite(coeffs->k) || coeffs->k <= 0.f)
return 0;
if (coeffs->ko != 0.f && coeffs->ko != 0.5f)
return 0;
if (!bw_is_finite(coeffs->max) || coeffs->max < 0.5f || coeffs->max > 1.f)
return 0;
if (!bw_is_finite(coeffs->gate) || coeffs->gate < 0.f || coeffs->gate > 1.f)
return 0;
}
#endif
return 1;
}
#ifdef __cplusplus
}
#ifndef BW_CXX_NO_ARRAY
# include <array>
#endif
namespace Brickworks {
/*** Public C++ API ***/
/*! api_cpp {{{
* ##### Brickworks::BDReduce
* ```>>> */
template<size_t N_CHANNELS>
class BDReduce {
public:
BDReduce();
void setSampleRate(
float sampleRate);
void reset();
void process(
const float * const * x,
float * const * y,
size_t nSamples);
#ifndef BW_CXX_NO_ARRAY
void process(
std::array<const float *, N_CHANNELS> x,
std::array<float *, N_CHANNELS> y,
size_t nSamples);
#endif
void setBitDepth(
char value);
void setSilenceDc(
char value);
void setGateLin(
float value);
void setGateDBFS(
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_bd_reduce_coeffs coeffs;
};
template<size_t N_CHANNELS>
inline BDReduce<N_CHANNELS>::BDReduce() {
bw_bd_reduce_init(&coeffs);
}
template<size_t N_CHANNELS>
inline void BDReduce<N_CHANNELS>::setSampleRate(
float sampleRate) {
bw_bd_reduce_set_sample_rate(&coeffs, sampleRate);
}
template<size_t N_CHANNELS>
inline void BDReduce<N_CHANNELS>::reset() {
bw_bd_reduce_reset_coeffs(&coeffs);
}
template<size_t N_CHANNELS>
inline void BDReduce<N_CHANNELS>::process(
const float * const * x,
float * const * y,
size_t nSamples) {
bw_bd_reduce_process_multi(&coeffs, x, y, N_CHANNELS, nSamples);
}
#ifndef BW_CXX_NO_ARRAY
template<size_t N_CHANNELS>
inline void BDReduce<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);
}
#endif
template<size_t N_CHANNELS>
inline void BDReduce<N_CHANNELS>::setBitDepth(
char value) {
bw_bd_reduce_set_bit_depth(&coeffs, value);
}
template<size_t N_CHANNELS>
inline void BDReduce<N_CHANNELS>::setSilenceDc(
char value) {
bw_bd_reduce_set_silence_dc(&coeffs, value);
}
template<size_t N_CHANNELS>
inline void BDReduce<N_CHANNELS>::setGateLin(
float value) {
bw_bd_reduce_set_gate_lin(&coeffs, value);
}
template<size_t N_CHANNELS>
inline void BDReduce<N_CHANNELS>::setGateDBFS(
float value) {
bw_bd_reduce_set_gate_dBFS(&coeffs, value);
}
}
#endif
#endif