/* * 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 . * * 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 {{{ * * }}} */ #ifndef BW_BD_REDUCE_H #define BW_BD_REDUCE_H #include #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 #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++) 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); } 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 #endif namespace Brickworks { /*** Public C++ API ***/ /*! api_cpp {{{ * ##### Brickworks::BDReduce * ```>>> */ template 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 x, std::array 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 inline BDReduce::BDReduce() { bw_bd_reduce_init(&coeffs); } template inline void BDReduce::setSampleRate( float sampleRate) { bw_bd_reduce_set_sample_rate(&coeffs, sampleRate); } template inline void BDReduce::reset() { bw_bd_reduce_reset_coeffs(&coeffs); } template inline void BDReduce::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 inline void BDReduce::process( std::array x, std::array y, size_t nSamples) { process(x.data(), y.data(), nSamples); } #endif template inline void BDReduce::setBitDepth( char value) { bw_bd_reduce_set_bit_depth(&coeffs, value); } template inline void BDReduce::setSilenceDc( char value) { bw_bd_reduce_set_silence_dc(&coeffs, value); } template inline void BDReduce::setGateLin( float value) { bw_bd_reduce_set_gate_lin(&coeffs, value); } template inline void BDReduce::setGateDBFS( float value) { bw_bd_reduce_set_gate_dBFS(&coeffs, value); } } #endif #endif