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usr.sbin/virtual_oss/virtual_oss/compressor.c
- This file was added.
| /*- | |||||
| * Copyright (c) 2020 Hans Petter Selasky | |||||
| * | |||||
| * Redistribution and use in source and binary forms, with or without | |||||
| * modification, are permitted provided that the following conditions | |||||
| * are met: | |||||
| * 1. Redistributions of source code must retain the above copyright | |||||
| * notice, this list of conditions and the following disclaimer. | |||||
| * 2. Redistributions in binary form must reproduce the above copyright | |||||
| * notice, this list of conditions and the following disclaimer in the | |||||
| * documentation and/or other materials provided with the distribution. | |||||
| * | |||||
| * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND | |||||
| * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE | |||||
| * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE | |||||
| * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE | |||||
| * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL | |||||
| * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS | |||||
| * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) | |||||
| * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT | |||||
| * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY | |||||
| * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF | |||||
| * SUCH DAMAGE. | |||||
| */ | |||||
| #include <sys/queue.h> | |||||
| #include <stdint.h> | |||||
| #include <string.h> | |||||
| #include "int.h" | |||||
| #include "virtual_oss.h" | |||||
| struct virtual_compressor voss_output_compressor_param = { | |||||
| .knee = 85, | |||||
| .attack = 3, | |||||
| .decay = 20, | |||||
| }; | |||||
| double voss_output_compressor_gain[VMAX_CHAN]; | |||||
| void | |||||
| voss_compressor(int64_t *buffer, double *p_ch_gain, | |||||
| const struct virtual_compressor *p_param, const unsigned samples, | |||||
| const unsigned maxchan, const int64_t fmt_max) | |||||
| { | |||||
| int64_t knee_amp; | |||||
| int64_t sample; | |||||
| unsigned ch; | |||||
| unsigned i; | |||||
| double amp; | |||||
| /* check if compressor is enabled */ | |||||
| if (p_param->enabled != 1) | |||||
| return; | |||||
| knee_amp = (fmt_max * p_param->knee) / VIRTUAL_OSS_KNEE_MAX; | |||||
| for (ch = i = 0; i != samples; i++) { | |||||
| sample = buffer[i]; | |||||
| if (sample < 0) | |||||
| sample = -sample; | |||||
| amp = p_ch_gain[ch]; | |||||
| if (sample > knee_amp) { | |||||
| const double gain = (double)knee_amp / (double)sample; | |||||
| if (gain < amp) | |||||
| amp += (gain - amp) / (1LL << p_param->attack); | |||||
| } | |||||
| buffer[i] *= amp; | |||||
| amp += (1.0 - amp) / (1LL << p_param->decay); | |||||
| p_ch_gain[ch] = amp; | |||||
| if (++ch == maxchan) | |||||
| ch = 0; | |||||
| } | |||||
| } | |||||