/* * 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 {{{ 1.1.1 }}} * 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 {{{ * * }}} */ #ifndef BW_SR_REDUCE_H #define BW_SR_REDUCE_H #include #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_set_sample_rate() * ```>>> */ static inline void bw_sr_reduce_set_sample_rate( bw_sr_reduce_coeffs * BW_RESTRICT coeffs, float sample_rate); /*! <<<``` * Sets the `sample_rate` (Hz) value in `coeffs`. * * #### bw_sr_reduce_reset_coeffs() * ```>>> */ static inline void bw_sr_reduce_reset_coeffs( bw_sr_reduce_coeffs * BW_RESTRICT coeffs); /*! <<<``` * Resets coefficients in `coeffs` to assume their target values. * * #### bw_sr_reduce_reset_state() * ```>>> */ static inline float bw_sr_reduce_reset_state( const bw_sr_reduce_coeffs * BW_RESTRICT coeffs, bw_sr_reduce_state * BW_RESTRICT state, float x_0); /*! <<<``` * Resets the given `state` to its initial values using the given `coeffs` * and the initial input value `x_0`. * * Returns the corresponding initial output value. * * #### bw_sr_reduce_reset_state_multi() * ```>>> */ static inline void bw_sr_reduce_reset_state_multi( const bw_sr_reduce_coeffs * BW_RESTRICT coeffs, bw_sr_reduce_state * BW_RESTRICT const * BW_RESTRICT state, const float * x_0, float * y_0, size_t n_channels); /*! <<<``` * Resets each of the `n_channels` `state`s to its initial values using the * given `coeffs` and the corresponding initial input value in the `x_0` * array. * * The corresponding initial output values are written into the `y_0` array, * if not `BW_NULL`. * * #### bw_sr_reduce_update_coeffs_ctrl() * ```>>> */ static inline void bw_sr_reduce_update_coeffs_ctrl( bw_sr_reduce_coeffs * BW_RESTRICT coeffs); /*! <<<``` * Triggers control-rate update of coefficients in `coeffs`. * * #### bw_sr_reduce_update_coeffs_audio() * ```>>> */ static inline void bw_sr_reduce_update_coeffs_audio( bw_sr_reduce_coeffs * BW_RESTRICT coeffs); /*! <<<``` * Triggers audio-rate update of coefficients in `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`. * * #### bw_sr_reduce_coeffs_is_valid() * ```>>> */ static inline char bw_sr_reduce_coeffs_is_valid( const bw_sr_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_sr_reduce_coeffs`. * * #### bw_sr_reduce_state_is_valid() * ```>>> */ static inline char bw_sr_reduce_state_is_valid( const bw_sr_reduce_coeffs * BW_RESTRICT coeffs, const bw_sr_reduce_state * BW_RESTRICT state); /*! <<<``` * Tries to determine whether `state` 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. * * If `coeffs` is not `BW_NULL` extra cross-checks might be performed * (`state` is supposed to be associated to `coeffs`). * * `state` must at least point to a readable memory block of size greater * than or equal to that of `bw_sr_reduce_state`. * }}} */ #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_sr_reduce_coeffs_state { bw_sr_reduce_coeffs_state_invalid, bw_sr_reduce_coeffs_state_init, bw_sr_reduce_coeffs_state_set_sample_rate, bw_sr_reduce_coeffs_state_reset_coeffs }; #endif struct bw_sr_reduce_coeffs { #ifdef BW_DEBUG_DEEP uint32_t hash; enum bw_sr_reduce_coeffs_state state; uint32_t reset_id; #endif // Parameters float ratio; }; struct bw_sr_reduce_state { #ifdef BW_DEBUG_DEEP uint32_t hash; uint32_t coeffs_reset_id; #endif // States float phase; float y_z1; }; static inline void bw_sr_reduce_init( bw_sr_reduce_coeffs * BW_RESTRICT coeffs) { BW_ASSERT(coeffs != BW_NULL); coeffs->ratio = 1.f; #ifdef BW_DEBUG_DEEP coeffs->hash = bw_hash_sdbm("bw_sr_reduce_coeffs"); coeffs->state = bw_sr_reduce_coeffs_state_init; coeffs->reset_id = coeffs->hash + 1; #endif BW_ASSERT_DEEP(bw_sr_reduce_coeffs_is_valid(coeffs)); BW_ASSERT_DEEP(coeffs->state == bw_sr_reduce_coeffs_state_init); } static inline void bw_sr_reduce_set_sample_rate( bw_sr_reduce_coeffs * BW_RESTRICT coeffs, float sample_rate) { BW_ASSERT(coeffs != BW_NULL); BW_ASSERT_DEEP(bw_sr_reduce_coeffs_is_valid(coeffs)); BW_ASSERT_DEEP(coeffs->state >= bw_sr_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_sr_reduce_coeffs_state_set_sample_rate; #endif BW_ASSERT_DEEP(bw_sr_reduce_coeffs_is_valid(coeffs)); BW_ASSERT_DEEP(coeffs->state == bw_sr_reduce_coeffs_state_set_sample_rate); } static inline void bw_sr_reduce_reset_coeffs( bw_sr_reduce_coeffs * BW_RESTRICT coeffs) { BW_ASSERT(coeffs != BW_NULL); BW_ASSERT_DEEP(bw_sr_reduce_coeffs_is_valid(coeffs)); BW_ASSERT_DEEP(coeffs->state >= bw_sr_reduce_coeffs_state_set_sample_rate); (void)coeffs; #ifdef BW_DEBUG_DEEP coeffs->state = bw_sr_reduce_coeffs_state_reset_coeffs; coeffs->reset_id++; #endif BW_ASSERT_DEEP(bw_sr_reduce_coeffs_is_valid(coeffs)); BW_ASSERT_DEEP(coeffs->state == bw_sr_reduce_coeffs_state_reset_coeffs); } static inline float bw_sr_reduce_reset_state( const bw_sr_reduce_coeffs * BW_RESTRICT coeffs, bw_sr_reduce_state * BW_RESTRICT state, float x_0) { BW_ASSERT(coeffs != BW_NULL); BW_ASSERT_DEEP(bw_sr_reduce_coeffs_is_valid(coeffs)); BW_ASSERT_DEEP(coeffs->state >= bw_sr_reduce_coeffs_state_reset_coeffs); BW_ASSERT(state != BW_NULL); BW_ASSERT(bw_is_finite(x_0)); (void)coeffs; state->y_z1 = x_0; state->phase = 1.f; const float y = x_0; #ifdef BW_DEBUG_DEEP state->hash = bw_hash_sdbm("bw_sr_reduce_state"); state->coeffs_reset_id = coeffs->reset_id; #endif BW_ASSERT_DEEP(bw_sr_reduce_coeffs_is_valid(coeffs)); BW_ASSERT_DEEP(coeffs->state >= bw_sr_reduce_coeffs_state_reset_coeffs); BW_ASSERT_DEEP(bw_sr_reduce_state_is_valid(coeffs, state)); BW_ASSERT(bw_is_finite(y)); return y; } static inline void bw_sr_reduce_reset_state_multi( const bw_sr_reduce_coeffs * BW_RESTRICT coeffs, bw_sr_reduce_state * BW_RESTRICT const * BW_RESTRICT state, const float * x_0, float * y_0, size_t n_channels) { BW_ASSERT(coeffs != BW_NULL); BW_ASSERT_DEEP(bw_sr_reduce_coeffs_is_valid(coeffs)); BW_ASSERT_DEEP(coeffs->state >= bw_sr_reduce_coeffs_state_reset_coeffs); BW_ASSERT(state != 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(state[i] != state[j]); #endif BW_ASSERT(x_0 != BW_NULL); if (y_0 != BW_NULL) for (size_t i = 0; i < n_channels; i++) y_0[i] = bw_sr_reduce_reset_state(coeffs, state[i], x_0[i]); else for (size_t i = 0; i < n_channels; i++) bw_sr_reduce_reset_state(coeffs, state[i], x_0[i]); BW_ASSERT_DEEP(bw_sr_reduce_coeffs_is_valid(coeffs)); BW_ASSERT_DEEP(coeffs->state >= bw_sr_reduce_coeffs_state_reset_coeffs); BW_ASSERT_DEEP(y_0 != BW_NULL ? bw_has_only_finite(y_0, n_channels) : 1); } static inline void bw_sr_reduce_update_coeffs_ctrl( bw_sr_reduce_coeffs * BW_RESTRICT coeffs) { BW_ASSERT(coeffs != BW_NULL); BW_ASSERT_DEEP(bw_sr_reduce_coeffs_is_valid(coeffs)); BW_ASSERT_DEEP(coeffs->state >= bw_sr_reduce_coeffs_state_reset_coeffs); (void)coeffs; } static inline void bw_sr_reduce_update_coeffs_audio( bw_sr_reduce_coeffs * BW_RESTRICT coeffs) { BW_ASSERT(coeffs != BW_NULL); BW_ASSERT_DEEP(bw_sr_reduce_coeffs_is_valid(coeffs)); BW_ASSERT_DEEP(coeffs->state >= bw_sr_reduce_coeffs_state_reset_coeffs); (void)coeffs; } static inline float bw_sr_reduce_process1( const bw_sr_reduce_coeffs * BW_RESTRICT coeffs, bw_sr_reduce_state * BW_RESTRICT state, float x) { BW_ASSERT(coeffs != BW_NULL); BW_ASSERT_DEEP(bw_sr_reduce_coeffs_is_valid(coeffs)); BW_ASSERT_DEEP(coeffs->state >= bw_sr_reduce_coeffs_state_reset_coeffs); BW_ASSERT(state != BW_NULL); BW_ASSERT_DEEP(bw_sr_reduce_state_is_valid(coeffs, state)); BW_ASSERT(bw_is_finite(x)); state->phase += coeffs->ratio; if (state->phase >= 1.f) { state->y_z1 = x; state->phase -= bw_floorf(state->phase); } const float y = state->y_z1; BW_ASSERT_DEEP(bw_sr_reduce_coeffs_is_valid(coeffs)); BW_ASSERT_DEEP(coeffs->state >= bw_sr_reduce_coeffs_state_reset_coeffs); BW_ASSERT_DEEP(bw_sr_reduce_state_is_valid(coeffs, state)); BW_ASSERT(bw_is_finite(y)); return y; } 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) { BW_ASSERT(coeffs != BW_NULL); BW_ASSERT_DEEP(bw_sr_reduce_coeffs_is_valid(coeffs)); BW_ASSERT_DEEP(coeffs->state >= bw_sr_reduce_coeffs_state_reset_coeffs); BW_ASSERT(state != BW_NULL); BW_ASSERT_DEEP(bw_sr_reduce_state_is_valid(coeffs, state)); BW_ASSERT(x != BW_NULL); BW_ASSERT_DEEP(bw_has_only_finite(x, n_samples)); BW_ASSERT(y != BW_NULL); for (size_t i = 0; i < n_samples; i++) y[i] = bw_sr_reduce_process1(coeffs, state, x[i]); BW_ASSERT_DEEP(bw_sr_reduce_coeffs_is_valid(coeffs)); BW_ASSERT_DEEP(coeffs->state >= bw_sr_reduce_coeffs_state_reset_coeffs); BW_ASSERT_DEEP(bw_sr_reduce_state_is_valid(coeffs, state)); BW_ASSERT_DEEP(bw_has_only_finite(y, n_samples)); } 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) { BW_ASSERT(coeffs != BW_NULL); BW_ASSERT_DEEP(bw_sr_reduce_coeffs_is_valid(coeffs)); BW_ASSERT_DEEP(coeffs->state >= bw_sr_reduce_coeffs_state_reset_coeffs); BW_ASSERT(state != 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(state[i] != state[j]); #endif 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 for (size_t i = 0; i < n_channels; i++) bw_sr_reduce_process(coeffs, state[i], x[i], y[i], n_samples); BW_ASSERT_DEEP(bw_sr_reduce_coeffs_is_valid(coeffs)); BW_ASSERT_DEEP(coeffs->state >= bw_sr_reduce_coeffs_state_reset_coeffs); } static inline void bw_sr_reduce_set_ratio( bw_sr_reduce_coeffs * BW_RESTRICT coeffs, float value) { BW_ASSERT(coeffs != BW_NULL); BW_ASSERT_DEEP(bw_sr_reduce_coeffs_is_valid(coeffs)); BW_ASSERT_DEEP(coeffs->state >= bw_sr_reduce_coeffs_state_init); BW_ASSERT(bw_is_finite(value)); BW_ASSERT(value >= 0.f && value <= 1.f); coeffs->ratio = value; BW_ASSERT_DEEP(bw_sr_reduce_coeffs_is_valid(coeffs)); BW_ASSERT_DEEP(coeffs->state >= bw_sr_reduce_coeffs_state_init); } static inline char bw_sr_reduce_coeffs_is_valid( const bw_sr_reduce_coeffs * BW_RESTRICT coeffs) { BW_ASSERT(coeffs != BW_NULL); #ifdef BW_DEBUG_DEEP if (coeffs->hash != bw_hash_sdbm("bw_sr_reduce_coeffs")) return 0; if (coeffs->state < bw_sr_reduce_coeffs_state_init || coeffs->state > bw_sr_reduce_coeffs_state_reset_coeffs) return 0; #endif return bw_is_finite(coeffs->ratio) && coeffs->ratio >= 0.f && coeffs->ratio <= 1.f; } static inline char bw_sr_reduce_state_is_valid( const bw_sr_reduce_coeffs * BW_RESTRICT coeffs, const bw_sr_reduce_state * BW_RESTRICT state) { BW_ASSERT(state != BW_NULL); #ifdef BW_DEBUG_DEEP if (state->hash != bw_hash_sdbm("bw_sr_reduce_state")) return 0; if (coeffs != BW_NULL && coeffs->reset_id != state->coeffs_reset_id) return 0; #endif (void)coeffs; return bw_is_finite(state->phase) && state->phase >= 0.f && bw_is_finite(state->y_z1); } #ifdef __cplusplus } #ifndef BW_CXX_NO_ARRAY # include #endif namespace Brickworks { /*** Public C++ API ***/ /*! api_cpp {{{ * ##### Brickworks::SRReduce * ```>>> */ template class SRReduce { public: SRReduce(); void setSampleRate( float sampleRate); void reset( float x0 = 0.f, float * BW_RESTRICT y0 = nullptr); #ifndef BW_CXX_NO_ARRAY void reset( float x0, std::array * BW_RESTRICT y0); #endif void reset( const float * x0, float * y0 = nullptr); #ifndef BW_CXX_NO_ARRAY void reset( std::array x0, std::array * BW_RESTRICT y0 = nullptr); #endif 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 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 inline SRReduce::SRReduce() { bw_sr_reduce_init(&coeffs); for (size_t i = 0; i < N_CHANNELS; i++) statesP[i] = states + i; } template inline void SRReduce::setSampleRate( float sampleRate) { bw_sr_reduce_set_sample_rate(&coeffs, sampleRate); } template inline void SRReduce::reset( float x0, float * BW_RESTRICT y0) { bw_sr_reduce_reset_coeffs(&coeffs); if (y0 != nullptr) for (size_t i = 0; i < N_CHANNELS; i++) y0[i] = bw_sr_reduce_reset_state(&coeffs, states + i, x0); else for (size_t i = 0; i < N_CHANNELS; i++) bw_sr_reduce_reset_state(&coeffs, states + i, x0); } #ifndef BW_CXX_NO_ARRAY template inline void SRReduce::reset( float x0, std::array * BW_RESTRICT y0) { reset(x0, y0 != nullptr ? y0->data() : nullptr); } #endif template inline void SRReduce::reset( const float * x0, float * y0) { bw_sr_reduce_reset_coeffs(&coeffs); bw_sr_reduce_reset_state_multi(&coeffs, statesP, x0, y0, N_CHANNELS); } #ifndef BW_CXX_NO_ARRAY template inline void SRReduce::reset( std::array x0, std::array * BW_RESTRICT y0) { reset(x0.data(), y0 != nullptr ? y0->data() : nullptr); } #endif template inline void SRReduce::process( const float * const * x, float * const * y, size_t nSamples) { bw_sr_reduce_process_multi(&coeffs, statesP, x, y, N_CHANNELS, nSamples); } #ifndef BW_CXX_NO_ARRAY template inline void SRReduce::process( std::array x, std::array y, size_t nSamples) { process(x.data(), y.data(), nSamples); } #endif template inline void SRReduce::setRatio(float value) { bw_sr_reduce_set_ratio(&coeffs, value); } } #endif #endif