384 lines
13 KiB
C
384 lines
13 KiB
C
/*
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* Brickworks
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*
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* Copyright (C) 2022, 2023 Orastron Srl unipersonale
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*
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* Brickworks is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, version 3 of the License.
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*
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* Brickworks is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with Brickworks. If not, see <http://www.gnu.org/licenses/>.
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*
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* File author: Stefano D'Angelo
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*/
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/*!
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* module_type {{{ dsp }}}
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* version {{{ 0.5.0 }}}
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* requires {{{ bw_common bw_config bw_math }}}
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* description {{{
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* Slew-rate limiter with separate maximum increasing and decreasing rates.
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* }}}
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* changelog {{{
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* <ul>
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* <li>Version <strong>0.5.0</strong>:
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* <ul>
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* <li>Added <code>bw_slew_lim_process_multi()</code>.</li>
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* <li>Fixed documentation of <code>bw_slew_lim_process()</code>.</li>
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* <li>Fixed unused parameter warnings.</li>
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* <li>Added C++ wrapper.</li>
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* </ul>
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* </li>
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* <li>Version <strong>0.2.0</strong>:
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* <ul>
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* <li>Refactored API.</li>
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* </ul>
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* </li>
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* <li>Version <strong>0.1.0</strong>:
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* <ul>
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* <li>First release.</li>
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* </ul>
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* </li>
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* </ul>
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* }}}
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*/
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#ifndef _BW_SLEW_LIM_H
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#define _BW_SLEW_LIM_H
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#ifdef __cplusplus
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extern "C" {
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#endif
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#include <bw_common.h>
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/*! api {{{
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* #### bw_slew_lim_coeffs
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* ```>>> */
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typedef struct _bw_slew_lim_coeffs bw_slew_lim_coeffs;
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/*! <<<```
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* Coefficients and related.
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*
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* #### bw_slew_lim_state
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* ```>>> */
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typedef struct _bw_slew_lim_state bw_slew_lim_state;
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/*! <<<```
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* Internal state and related.
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*
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* #### bw_slew_lim_init()
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* ```>>> */
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static inline void bw_slew_lim_init(bw_slew_lim_coeffs *BW_RESTRICT coeffs);
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/*! <<<```
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* Initializes input parameter values in `coeffs`.
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*
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* #### bw_slew_lim_set_sample_rate()
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* ```>>> */
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static inline void bw_slew_lim_set_sample_rate(bw_slew_lim_coeffs *BW_RESTRICT coeffs, float sample_rate);
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/*! <<<```
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* Sets the `sample_rate` (Hz) value in `coeffs`.
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*
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* #### bw_slew_lim_reset_coeffs()
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* ```>>> */
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static inline void bw_slew_lim_reset_coeffs(bw_slew_lim_coeffs *BW_RESTRICT coeffs);
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/*! <<<```
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* Resets coefficients in `coeffs` to assume their target values.
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*
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* #### bw_slew_lim_reset_state()
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* ```>>> */
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static inline void bw_slew_lim_reset_state(const bw_slew_lim_coeffs *BW_RESTRICT coeffs, bw_slew_lim_state *BW_RESTRICT state, float y_z1);
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/*! <<<```
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* Resets the given `state` to its initial values using the given `coeffs`
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* and the quiescent/equilibrium value `y_z1`.
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*
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* #### bw_slew_lim_update_coeffs_ctrl()
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* ```>>> */
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static inline void bw_slew_lim_update_coeffs_ctrl(bw_slew_lim_coeffs *BW_RESTRICT coeffs);
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/*! <<<```
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* Triggers control-rate update of coefficients in `coeffs`.
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*
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* #### bw_one_pole_update_coeffs_audio()
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* ```>>> */
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static inline void bw_slew_lim_update_coeffs_audio(bw_slew_lim_coeffs *BW_RESTRICT coeffs);
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/*! <<<```
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* Triggers audio-rate update of coefficients in `coeffs`.
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*
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* #### bw_slew_lim_process1\*()
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* ```>>> */
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static inline float bw_slew_lim_process1(const bw_slew_lim_coeffs *BW_RESTRICT coeffs, bw_slew_lim_state *BW_RESTRICT state, float x);
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static inline float bw_slew_lim_process1_up(const bw_slew_lim_coeffs *BW_RESTRICT coeffs, bw_slew_lim_state *BW_RESTRICT state, float x);
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static inline float bw_slew_lim_process1_down(const bw_slew_lim_coeffs *BW_RESTRICT coeffs, bw_slew_lim_state *BW_RESTRICT state, float x);
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/*! <<<```
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* These function process one input sample `x` using `coeffs`, while using
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* and updating `state`. They return the corresponding output sample.
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*
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* In particular:
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* * `bw_slew_lim_process1()` assumes that both the maximum upgoing and
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* downgoing variation rates are finite;
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* * `bw_slew_lim_process1_up()` assumes that both the maximum upgoing
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* variation rate is finite and the maximum downgoing variation rate is
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* infinite;
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* * `bw_slew_lim_process1_down()` assumes that both the maximum upgoing
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* variation rate is infinite and the maximum downgoing variation rate is
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* finite.
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*
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* #### bw_slew_lim_process()
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* ```>>> */
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static inline void bw_slew_lim_process(bw_slew_lim_coeffs *BW_RESTRICT coeffs, bw_slew_lim_state *BW_RESTRICT state, const float *x, float *y, int n_samples);
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/*! <<<```
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* Processes the first `n_samples` of the input buffer `x` and fills the
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* first `n_samples` of the output buffer `y`, while using and updating both
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* `coeffs` and `state` (control and audio rate).
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*
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* `y` may be `NULL`.
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*
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* #### bw_slew_lim_process_multi()
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* ```>>> */
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static inline void bw_slew_lim_process_multi(bw_slew_lim_coeffs *BW_RESTRICT coeffs, bw_slew_lim_state **BW_RESTRICT state, const float **x, float **y, int n_channels, int n_samples);
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/*! <<<```
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* Processes the first `n_samples` of the `n_channels` input buffers `x` and
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* fills the first `n_samples` of the `n_channels` output buffers `y`, while
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* using and updating both the common `coeffs` and each of the `n_channels`
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* `state`s (control and audio rate).
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*
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* `y` or any element of `y` may be `NULL`.
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*
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* #### bw_slew_lim_set_max_rate()
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* ```>>> */
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static inline void bw_slew_lim_set_max_rate(bw_slew_lim_coeffs *BW_RESTRICT coeffs, float value);
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/*! <<<```
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* Sets both the maximum increasing and decreasing variation rate to the
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* given `value` (1/s) in `coeffs`.
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*
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* `value` represents the maximum variation per second and must be
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* non-negative.
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*
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* This is equivalent to calling both `bw_slew_lim_set_max_inc_rate()` and
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* `bw_slew_lim_set_max_dec_rate()` with same `coeffs` and `value`.
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*
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* Default value: `INFINITY`.
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* >>> */
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/*! ...
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* #### bw_slew_lim_set_max_rate_up()
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* ```>>> */
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static inline void bw_slew_lim_set_max_rate_up(bw_slew_lim_coeffs *BW_RESTRICT coeffs, float value);
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/*! <<<```
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* Sets the maximum increasing variation rate to the given `value` (1/s) in
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* `coeffs`.
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*
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* `value` represents the maximum variation per second and must be
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* non-negative.
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*
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* Default value: `INFINITY`.
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* >>> */
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/*! ...
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* #### bw_slew_lim_set_max_inc_rate()
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* ```>>> */
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static inline void bw_slew_lim_set_max_rate_down(bw_slew_lim_coeffs *BW_RESTRICT coeffs, float value);
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/*! <<<```
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* Sets the maximum decreasing variation rate to the given `value` (1/s) in
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* `coeffs`.
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*
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* `value` represents the maximum variation per second and must be
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* non-negative.
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*
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* Default value: `INFINITY`.
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* }}} */
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static inline float bw_slew_lim_get_y_z1(const bw_slew_lim_state *BW_RESTRICT state);
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/*** Implementation ***/
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/* WARNING: This part of the file is not part of the public API. Its content may
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* change at any time in future versions. Please, do not use it directly. */
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#include <bw_math.h>
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struct _bw_slew_lim_coeffs {
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// Coefficients
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float T;
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float max_inc;
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float max_dec;
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// Parameters
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float max_rate_up;
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float max_rate_down;
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};
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struct _bw_slew_lim_state {
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float y_z1;
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};
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static inline void bw_slew_lim_init(bw_slew_lim_coeffs *BW_RESTRICT coeffs) {
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coeffs->max_inc = INFINITY;
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coeffs->max_dec = INFINITY;
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}
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static inline void bw_slew_lim_set_sample_rate(bw_slew_lim_coeffs *BW_RESTRICT coeffs, float sample_rate) {
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coeffs->T = 1.f / sample_rate;
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}
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static inline void bw_slew_lim_reset_coeffs(bw_slew_lim_coeffs *BW_RESTRICT coeffs) {
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bw_slew_lim_update_coeffs_ctrl(coeffs);
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}
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static inline void bw_slew_lim_reset_state(const bw_slew_lim_coeffs *BW_RESTRICT coeffs, bw_slew_lim_state *BW_RESTRICT state, float y_z1) {
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(void)coeffs;
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state->y_z1 = y_z1;
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}
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static inline void bw_slew_lim_update_coeffs_ctrl(bw_slew_lim_coeffs *BW_RESTRICT coeffs) {
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// tracking parameter changes is more trouble than it's worth
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coeffs->max_inc = coeffs->T * coeffs->max_rate_up;
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coeffs->max_dec = coeffs->T * coeffs->max_rate_down;
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}
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static inline void bw_slew_lim_update_coeffs_audio(bw_slew_lim_coeffs *BW_RESTRICT coeffs) {
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(void)coeffs;
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}
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static inline float bw_slew_lim_process1(const bw_slew_lim_coeffs *BW_RESTRICT coeffs, bw_slew_lim_state *BW_RESTRICT state, float x) {
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float y = bw_clipf(x, state->y_z1 - coeffs->max_dec, state->y_z1 + coeffs->max_inc);
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state->y_z1 = y;
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return y;
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}
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static inline float bw_slew_lim_process1_up(const bw_slew_lim_coeffs *BW_RESTRICT coeffs, bw_slew_lim_state *BW_RESTRICT state, float x) {
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float y = bw_minf(x, state->y_z1 + coeffs->max_inc);
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state->y_z1 = y;
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return y;
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}
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static inline float bw_slew_lim_process1_down(const bw_slew_lim_coeffs *BW_RESTRICT coeffs, bw_slew_lim_state *BW_RESTRICT state, float x) {
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float y = bw_maxf(x, state->y_z1 - coeffs->max_dec);
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state->y_z1 = y;
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return y;
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}
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static inline void bw_slew_lim_process(bw_slew_lim_coeffs *BW_RESTRICT coeffs, bw_slew_lim_state *BW_RESTRICT state, const float *x, float *y, int n_samples) {
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bw_slew_lim_update_coeffs_ctrl(coeffs);
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if (y != NULL) {
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if (coeffs->max_rate_up != INFINITY) {
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if (coeffs->max_rate_down != INFINITY)
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for (int i = 0; i < n_samples; i++)
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y[i] = bw_slew_lim_process1(coeffs, state, x[i]);
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else
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for (int i = 0; i < n_samples; i++)
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y[i] = bw_slew_lim_process1_up(coeffs, state, x[i]);
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} else {
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if (coeffs->max_rate_down != INFINITY)
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for (int i = 0; i < n_samples; i++)
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y[i] = bw_slew_lim_process1_down(coeffs, state, x[i]);
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else {
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for (int i = 0; i < n_samples; i++)
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y[i] = x[i];
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state->y_z1 = x[n_samples - 1];
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}
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}
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} else {
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if (coeffs->max_rate_up != INFINITY) {
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if (coeffs->max_rate_down != INFINITY)
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for (int i = 0; i < n_samples; i++)
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bw_slew_lim_process1(coeffs, state, x[i]);
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else
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for (int i = 0; i < n_samples; i++)
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bw_slew_lim_process1_up(coeffs, state, x[i]);
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} else {
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if (coeffs->max_rate_down != INFINITY)
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for (int i = 0; i < n_samples; i++)
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bw_slew_lim_process1_down(coeffs, state, x[i]);
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else
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state->y_z1 = x[n_samples - 1];
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}
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}
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}
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static inline void bw_slew_lim_process_multi(bw_slew_lim_coeffs *BW_RESTRICT coeffs, bw_slew_lim_state **BW_RESTRICT state, const float **x, float **y, int n_channels, int n_samples) {
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bw_slew_lim_update_coeffs_ctrl(coeffs);
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if (y != NULL) {
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if (coeffs->max_rate_up != INFINITY) {
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if (coeffs->max_rate_down != INFINITY)
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for (int j = 0; j < n_channels; j++)
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if (y[j] != NULL)
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for (int i = 0; i < n_samples; i++)
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y[j][i] = bw_slew_lim_process1(coeffs, state[j], x[j][i]);
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else
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for (int i = 0; i < n_samples; i++)
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bw_slew_lim_process1(coeffs, state[j], x[j][i]);
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else
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for (int j = 0; j < n_channels; j++)
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for (int i = 0; i < n_samples; i++)
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if (y[j] != NULL)
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y[j][i] = bw_slew_lim_process1_up(coeffs, state[j], x[j][i]);
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else
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bw_slew_lim_process1_up(coeffs, state[j], x[j][i]);
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} else {
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if (coeffs->max_rate_down != INFINITY)
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for (int j = 0; j < n_channels; j++)
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if (y[j] != NULL)
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for (int i = 0; i < n_samples; i++)
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y[j][i] = bw_slew_lim_process1_down(coeffs, state[j], x[j][i]);
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else
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for (int i = 0; i < n_samples; i++)
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bw_slew_lim_process1_down(coeffs, state[j], x[j][i]);
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else
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for (int j = 0; j < n_channels; j++) {
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if (y[j] != NULL)
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for (int i = 0; i < n_samples; i++)
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y[j][i] = x[j][i];
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state[j]->y_z1 = x[j][n_samples - 1];
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}
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}
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} else {
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if (coeffs->max_rate_up != INFINITY) {
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if (coeffs->max_rate_down != INFINITY)
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for (int j = 0; j < n_channels; j++)
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for (int i = 0; i < n_samples; i++)
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bw_slew_lim_process1(coeffs, state[j], x[j][i]);
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else
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for (int j = 0; j < n_channels; j++)
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for (int i = 0; i < n_samples; i++)
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bw_slew_lim_process1_up(coeffs, state[j], x[j][i]);
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} else {
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if (coeffs->max_rate_down != INFINITY)
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for (int j = 0; j < n_channels; j++)
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for (int i = 0; i < n_samples; i++)
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bw_slew_lim_process1_down(coeffs, state[j], x[j][i]);
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else
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for (int j = 0; j < n_channels; j++)
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state[j]->y_z1 = x[j][n_samples - 1];
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}
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}
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}
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static inline void bw_slew_lim_set_max_rate(bw_slew_lim_coeffs *BW_RESTRICT coeffs, float value) {
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bw_slew_lim_set_max_rate_up(coeffs, value);
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bw_slew_lim_set_max_rate_down(coeffs, value);
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}
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static inline void bw_slew_lim_set_max_rate_up(bw_slew_lim_coeffs *BW_RESTRICT coeffs, float value) {
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coeffs->max_rate_up = value;
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}
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static inline void bw_slew_lim_set_max_rate_down(bw_slew_lim_coeffs *BW_RESTRICT coeffs, float value) {
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coeffs->max_rate_down = value;
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}
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static inline float bw_slew_lim_get_y_z1(const bw_slew_lim_state *BW_RESTRICT state) {
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return state->y_z1;
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}
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#ifdef __cplusplus
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}
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#endif
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#endif
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