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71 lines
2 KiB
C
71 lines
2 KiB
C
/* Simple DLL
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*
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* Copyright © 2019 Wim Taymans
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*
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* Permission is hereby granted, free of charge, to any person obtaining a
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* copy of this software and associated documentation files (the "Software"),
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* to deal in the Software without restriction, including without limitation
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* the rights to use, copy, modify, merge, publish, distribute, sublicense,
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* and/or sell copies of the Software, and to permit persons to whom the
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* Software is furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice (including the next
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* paragraph) shall be included in all copies or substantial portions of the
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* Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
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* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
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* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
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* DEALINGS IN THE SOFTWARE.
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*/
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#ifndef SPA_DLL_H
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#define SPA_DLL_H
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#ifdef __cplusplus
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extern "C" {
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#endif
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#include <stddef.h>
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#include <math.h>
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#define SPA_DLL_BW_MAX 0.128
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#define SPA_DLL_BW_MIN 0.016
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struct spa_dll {
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double bw;
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double z1, z2, z3;
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double w0, w1, w2;
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};
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static inline void spa_dll_init(struct spa_dll *dll)
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{
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dll->bw = 0.0;
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dll->z1 = dll->z2 = dll->z3 = 0.0;
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}
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static inline void spa_dll_set_bw(struct spa_dll *dll, double bw, uint32_t period, uint32_t rate)
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{
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double w = 2 * M_PI * bw * period / rate;
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dll->w0 = 1.0 - exp (-20.0 * w);
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dll->w1 = w * 1.5 / period;
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dll->w2 = w / 1.5;
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dll->bw = bw;
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}
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static inline double spa_dll_update(struct spa_dll *dll, double err)
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{
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dll->z1 += dll->w0 * (dll->w1 * err - dll->z1);
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dll->z2 += dll->w0 * (dll->z1 - dll->z2);
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dll->z3 += dll->w2 * dll->z2;
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return 1.0 - (dll->z2 + dll->z3);
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}
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#ifdef __cplusplus
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} /* extern "C" */
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#endif
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#endif /* SPA_DLL_H */
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