515 lines
15 KiB
C++
515 lines
15 KiB
C++
/*
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* Brickworks
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*
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* Copyright (C) 2022-2024 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 {{{ 1.1.0 }}}
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* requires {{{ bw_common bw_math }}}
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* description {{{
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* Bit depth reducer.
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*
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* This is purely an audio effect, it doesn't actually produce an output
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* signal with a different encoding. The algorithm is deliberately crude to
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* obtain the characteristic noise due to lo-fi A/D quantization.
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* }}}
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* changelog {{{
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* <ul>
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* <li>Version <strong>1.1.0</strong>:
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* <ul>
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* <li>Now using <code>BW_NULL</code> and
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* <code>BW_CXX_NO_ARRAY</code>.</li>
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* </ul>
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* </li>
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* <li>Version <strong>1.0.0</strong>:
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* <ul>
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* <li>Added <code>bw_bd_reduce_set_sample_rate()</code>.</li>
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* <li><code>bw_bd_reduce_process()</code> and
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* <code>bw_bd_reduce_process_multi()</code> now use
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* <code>size_t</code> to count samples and channels.</li>
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* <li>Added more <code>const</code> specifiers to input
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* arguments.</li>
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* <li>Moved C++ code to C header.</li>
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* <li>Added overloaded C++ <code>process()</code> function taking
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* C-style arrays as arguments.</li>
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* <li>Removed usage of reserved identifiers.</li>
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* <li>Clearly specified parameter validity ranges.</li>
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* <li>Added debugging code.</li>
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* </ul>
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* </li>
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* <li>Version <strong>0.6.0</strong>:
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* <ul>
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* <li>Removed dependency on bw_config.</li>
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* </ul>
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* </li>
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* <li>Version <strong>0.5.0</strong>:
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* <ul>
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* <li>Added <code>bw_bd_reduce_process_multi()</code>.</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>0.4.0</strong>:
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* <ul>
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* <li>Fixed unused parameter warnings.</li>
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* </ul>
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* </li>
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* <li>Version <strong>0.3.0</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_BD_REDUCE_H
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#define BW_BD_REDUCE_H
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#include <bw_common.h>
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#ifdef __cplusplus
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extern "C" {
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#endif
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/*! api {{{
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* #### bw_bd_reduce_coeffs
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* ```>>> */
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typedef struct bw_bd_reduce_coeffs bw_bd_reduce_coeffs;
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/*! <<<```
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* Coefficients and related.
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*
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* #### bw_bd_reduce_init()
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* ```>>> */
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static inline void bw_bd_reduce_init(
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bw_bd_reduce_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_bw_reduce_set_sample_rate()
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* ```>>> */
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static inline void bw_bd_reduce_set_sample_rate(
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bw_bd_reduce_coeffs * BW_RESTRICT coeffs,
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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_bd_reduce_reset_coeffs()
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* ```>>> */
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static inline void bw_bd_reduce_reset_coeffs(
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bw_bd_reduce_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_bd_reduce_update_coeffs_ctrl()
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* ```>>> */
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static inline void bw_bd_reduce_update_coeffs_ctrl(
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bw_bd_reduce_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_bd_reduce_update_coeffs_audio()
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* ```>>> */
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static inline void bw_bd_reduce_update_coeffs_audio(
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bw_bd_reduce_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_bd_reduce_process1()
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* ```>>> */
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static inline float bw_bd_reduce_process1(
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const bw_bd_reduce_coeffs * BW_RESTRICT coeffs,
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float x);
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/*! <<<```
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* Processes one input sample `x` using `coeffs`. Returns the corresponding
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* output sample.
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*
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* #### bw_bd_reduce_process()
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* ```>>> */
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static inline void bw_bd_reduce_process(
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bw_bd_reduce_coeffs * BW_RESTRICT coeffs,
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const float * x,
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float * y,
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size_t 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
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* `coeffs` (control and audio rate).
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*
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* #### bw_bd_reduce_process_multi()
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* ```>>> */
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static inline void bw_bd_reduce_process_multi(
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bw_bd_reduce_coeffs * BW_RESTRICT coeffs,
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const float * const * x,
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float * const * y,
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size_t n_channels,
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size_t 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 the common `coeffs` (control and audio rate).
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*
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* #### bw_bd_reduce_set_bit_depth()
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* ```>>> */
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static inline void bw_bd_reduce_set_bit_depth(
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bw_bd_reduce_coeffs * BW_RESTRICT coeffs,
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char value);
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/*! <<<```
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* Sets the output bit depth `value` in `coeffs`.
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*
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* Valid range: [`1`, `64`].
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*
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* Default value: `16`.
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*
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* #### bw_bd_reduce_coeffs_is_valid()
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* ```>>> */
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static inline char bw_bd_reduce_coeffs_is_valid(
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const bw_bd_reduce_coeffs * BW_RESTRICT coeffs);
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/*! <<<```
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* Tries to determine whether `coeffs` is valid and returns non-`0` if it
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* seems to be the case and `0` if it is certainly not. False positives are
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* possible, false negatives are not.
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*
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* `coeffs` must at least point to a readable memory block of size greater
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* than or equal to that of `bw_bd_reduce_coeffs`.
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* }}} */
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#ifdef __cplusplus
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}
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#endif
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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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#ifdef __cplusplus
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extern "C" {
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#endif
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#ifdef BW_DEBUG_DEEP
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enum bw_bd_reduce_coeffs_state {
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bw_bd_reduce_coeffs_state_invalid,
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bw_bd_reduce_coeffs_state_init,
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bw_bd_reduce_coeffs_state_set_sample_rate,
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bw_bd_reduce_coeffs_state_reset_coeffs
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};
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#endif
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struct bw_bd_reduce_coeffs {
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#ifdef BW_DEBUG_DEEP
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uint32_t hash;
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enum bw_bd_reduce_coeffs_state state;
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#endif
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// Coefficients
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float ki;
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float k;
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float max;
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// Parameters
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char bit_depth;
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char bit_depth_prev;
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};
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static inline void bw_bd_reduce_init(
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bw_bd_reduce_coeffs * BW_RESTRICT coeffs) {
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BW_ASSERT(coeffs != BW_NULL);
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coeffs->bit_depth = 16;
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#ifdef BW_DEBUG_DEEP
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coeffs->hash = bw_hash_sdbm("bw_bd_reduce_coeffs");
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coeffs->state = bw_bd_reduce_coeffs_state_init;
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#endif
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BW_ASSERT_DEEP(bw_bd_reduce_coeffs_is_valid(coeffs));
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BW_ASSERT_DEEP(coeffs->state == bw_bd_reduce_coeffs_state_init);
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}
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static inline void bw_bd_reduce_set_sample_rate(
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bw_bd_reduce_coeffs * BW_RESTRICT coeffs,
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float sample_rate) {
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BW_ASSERT(coeffs != BW_NULL);
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BW_ASSERT_DEEP(bw_bd_reduce_coeffs_is_valid(coeffs));
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BW_ASSERT_DEEP(coeffs->state >= bw_bd_reduce_coeffs_state_init);
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BW_ASSERT(bw_is_finite(sample_rate) && sample_rate > 0.f);
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(void)coeffs;
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(void)sample_rate;
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#ifdef BW_DEBUG_DEEP
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coeffs->state = bw_bd_reduce_coeffs_state_set_sample_rate;
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#endif
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BW_ASSERT_DEEP(bw_bd_reduce_coeffs_is_valid(coeffs));
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BW_ASSERT_DEEP(coeffs->state == bw_bd_reduce_coeffs_state_set_sample_rate);
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}
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static inline void bw_bd_reduce_do_update_coeffs_ctrl(
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bw_bd_reduce_coeffs * BW_RESTRICT coeffs) {
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if (coeffs->bit_depth_prev != coeffs->bit_depth) {
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coeffs->k = bw_pow2f(coeffs->bit_depth - 1);
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coeffs->ki = bw_rcpf(coeffs->k);
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coeffs->max = 1.f - 0.5f * coeffs->ki;
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coeffs->bit_depth_prev = coeffs->bit_depth;
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}
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}
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static inline void bw_bd_reduce_reset_coeffs(
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bw_bd_reduce_coeffs * BW_RESTRICT coeffs) {
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BW_ASSERT(coeffs != BW_NULL);
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BW_ASSERT_DEEP(bw_bd_reduce_coeffs_is_valid(coeffs));
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BW_ASSERT_DEEP(coeffs->state >= bw_bd_reduce_coeffs_state_set_sample_rate);
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coeffs->bit_depth_prev = 0;
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bw_bd_reduce_do_update_coeffs_ctrl(coeffs);
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#ifdef BW_DEBUG_DEEP
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coeffs->state = bw_bd_reduce_coeffs_state_reset_coeffs;
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#endif
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BW_ASSERT_DEEP(bw_bd_reduce_coeffs_is_valid(coeffs));
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BW_ASSERT_DEEP(coeffs->state == bw_bd_reduce_coeffs_state_reset_coeffs);
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}
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static inline void bw_bd_reduce_update_coeffs_ctrl(
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bw_bd_reduce_coeffs * BW_RESTRICT coeffs) {
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BW_ASSERT(coeffs != BW_NULL);
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BW_ASSERT_DEEP(bw_bd_reduce_coeffs_is_valid(coeffs));
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BW_ASSERT_DEEP(coeffs->state >= bw_bd_reduce_coeffs_state_reset_coeffs);
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bw_bd_reduce_do_update_coeffs_ctrl(coeffs);
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BW_ASSERT_DEEP(bw_bd_reduce_coeffs_is_valid(coeffs));
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BW_ASSERT_DEEP(coeffs->state >= bw_bd_reduce_coeffs_state_reset_coeffs);
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}
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static inline void bw_bd_reduce_update_coeffs_audio(
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bw_bd_reduce_coeffs * BW_RESTRICT coeffs) {
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BW_ASSERT(coeffs != BW_NULL);
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BW_ASSERT_DEEP(bw_bd_reduce_coeffs_is_valid(coeffs));
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BW_ASSERT_DEEP(coeffs->state >= bw_bd_reduce_coeffs_state_reset_coeffs);
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(void)coeffs;
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}
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static inline float bw_bd_reduce_process1(
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const bw_bd_reduce_coeffs * BW_RESTRICT coeffs,
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float x) {
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BW_ASSERT(coeffs != BW_NULL);
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BW_ASSERT_DEEP(bw_bd_reduce_coeffs_is_valid(coeffs));
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BW_ASSERT_DEEP(coeffs->state >= bw_bd_reduce_coeffs_state_reset_coeffs);
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BW_ASSERT(bw_is_finite(x));
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const float y = coeffs->ki * (bw_floorf(coeffs->k * bw_clipf(x, -coeffs->max, coeffs->max)) + 0.5f);
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BW_ASSERT_DEEP(bw_bd_reduce_coeffs_is_valid(coeffs));
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BW_ASSERT_DEEP(coeffs->state >= bw_bd_reduce_coeffs_state_reset_coeffs);
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BW_ASSERT(bw_is_finite(y));
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return y;
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}
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static inline void bw_bd_reduce_process(
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bw_bd_reduce_coeffs * BW_RESTRICT coeffs,
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const float * x,
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float * y,
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size_t n_samples) {
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BW_ASSERT(coeffs != BW_NULL);
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BW_ASSERT_DEEP(bw_bd_reduce_coeffs_is_valid(coeffs));
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BW_ASSERT_DEEP(coeffs->state >= bw_bd_reduce_coeffs_state_reset_coeffs);
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BW_ASSERT(x != BW_NULL);
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BW_ASSERT_DEEP(bw_has_only_finite(x, n_samples));
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BW_ASSERT(y != BW_NULL);
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bw_bd_reduce_update_coeffs_ctrl(coeffs);
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for (size_t i = 0; i < n_samples; i++)
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y[i] = bw_bd_reduce_process1(coeffs, x[i]);
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BW_ASSERT_DEEP(bw_bd_reduce_coeffs_is_valid(coeffs));
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BW_ASSERT_DEEP(coeffs->state >= bw_bd_reduce_coeffs_state_reset_coeffs);
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BW_ASSERT_DEEP(bw_has_only_finite(y, n_samples));
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}
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static inline void bw_bd_reduce_process_multi(
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bw_bd_reduce_coeffs * BW_RESTRICT coeffs,
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const float * const * x,
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float * const * y,
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size_t n_channels,
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size_t n_samples) {
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BW_ASSERT(coeffs != BW_NULL);
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BW_ASSERT_DEEP(bw_bd_reduce_coeffs_is_valid(coeffs));
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BW_ASSERT_DEEP(coeffs->state >= bw_bd_reduce_coeffs_state_reset_coeffs);
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BW_ASSERT(x != BW_NULL);
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BW_ASSERT(y != BW_NULL);
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#ifndef BW_NO_DEBUG
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for (size_t i = 0; i < n_channels; i++)
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for (size_t j = i + 1; j < n_channels; j++)
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BW_ASSERT(y[i] != y[j]);
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#endif
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bw_bd_reduce_update_coeffs_ctrl(coeffs);
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for (size_t i = 0; i < n_samples; i++)
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for (size_t j = 0; j < n_channels; j++)
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y[j][i] = bw_bd_reduce_process1(coeffs, x[j][i]);
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BW_ASSERT_DEEP(bw_bd_reduce_coeffs_is_valid(coeffs));
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BW_ASSERT_DEEP(coeffs->state >= bw_bd_reduce_coeffs_state_reset_coeffs);
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}
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static inline void bw_bd_reduce_set_bit_depth(
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bw_bd_reduce_coeffs * BW_RESTRICT coeffs,
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char value) {
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BW_ASSERT(coeffs != BW_NULL);
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BW_ASSERT_DEEP(bw_bd_reduce_coeffs_is_valid(coeffs));
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BW_ASSERT_DEEP(coeffs->state >= bw_bd_reduce_coeffs_state_init);
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BW_ASSERT(value >= 1 && value <= 64);
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coeffs->bit_depth = value;
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BW_ASSERT_DEEP(bw_bd_reduce_coeffs_is_valid(coeffs));
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BW_ASSERT_DEEP(coeffs->state >= bw_bd_reduce_coeffs_state_init);
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}
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static inline char bw_bd_reduce_coeffs_is_valid(
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const bw_bd_reduce_coeffs * BW_RESTRICT coeffs) {
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BW_ASSERT(coeffs != BW_NULL);
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#ifdef BW_DEBUG_DEEP
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if (coeffs->hash != bw_hash_sdbm("bw_bd_reduce_coeffs"))
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return 0;
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if (coeffs->state < bw_bd_reduce_coeffs_state_init || coeffs->state > bw_bd_reduce_coeffs_state_reset_coeffs)
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return 0;
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#endif
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if (coeffs->bit_depth < 1 || coeffs->bit_depth > 64)
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return 0;
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#ifdef BW_DEBUG_DEEP
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if (coeffs->state >= bw_bd_reduce_coeffs_state_reset_coeffs) {
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if (coeffs->bit_depth_prev < 1 || coeffs->bit_depth_prev > 64)
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return 0;
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if (!bw_is_finite(coeffs->k) || coeffs->k <= 0.f)
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return 0;
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if (!bw_is_finite(coeffs->ki) || coeffs->ki <= 0.f)
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return 0;
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if (!bw_is_finite(coeffs->max) || coeffs->max < 0.5f || coeffs->max > 1.f)
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return 0;
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}
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#endif
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return 1;
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}
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#ifdef __cplusplus
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}
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#ifndef BW_CXX_NO_ARRAY
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# include <array>
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#endif
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namespace Brickworks {
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/*** Public C++ API ***/
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/*! api_cpp {{{
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* ##### Brickworks::BDReduce
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* ```>>> */
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template<size_t N_CHANNELS>
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class BDReduce {
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public:
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BDReduce();
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void setSampleRate(
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float sampleRate);
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void reset();
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void process(
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const float * const * x,
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float * const * y,
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size_t nSamples);
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#ifndef BW_CXX_NO_ARRAY
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void process(
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std::array<const float *, N_CHANNELS> x,
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std::array<float *, N_CHANNELS> y,
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size_t nSamples);
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#endif
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|
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void setBitDepth(
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char value);
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|
/*! <<<...
|
|
* }
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|
* ```
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|
* }}} */
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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
|
|
* change at any time in future versions. Please, do not use it directly. */
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|
|
|
private:
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|
bw_bd_reduce_coeffs coeffs;
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|
};
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|
|
|
template<size_t N_CHANNELS>
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|
inline BDReduce<N_CHANNELS>::BDReduce() {
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|
bw_bd_reduce_init(&coeffs);
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|
}
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|
|
|
template<size_t N_CHANNELS>
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|
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);
|
|
}
|
|
|
|
}
|
|
#endif
|
|
|
|
#endif
|