PipeWire: spa/utils/dll.h Source File

PipeWire 0.3.51

dll.h
1/* Simple DLL
2 *
3 * Copyright © 2019 Wim Taymans
4 *
5 * Permission is hereby granted, free of charge, to any person obtaining a
6 * copy of this software and associated documentation files (the "Software"),
7 * to deal in the Software without restriction, including without limitation
8 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
9 * and/or sell copies of the Software, and to permit persons to whom the
10 * Software is furnished to do so, subject to the following conditions:
11 *
12 * The above copyright notice and this permission notice (including the next
13 * paragraph) shall be included in all copies or substantial portions of the
14 * Software.
15 *
16 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
17 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
18 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
19 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
20 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
21 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
22 * DEALINGS IN THE SOFTWARE.
23 */
24
25#ifndef SPA_DLL_H
26#define SPA_DLL_H
27
28#ifdef __cplusplus
29extern "C" {
30#endif
31
32#include <stddef.h>
33#include <math.h>
34
35#define SPA_DLL_BW_MAX 0.128
36#define SPA_DLL_BW_MIN 0.016
37
38struct spa_dll {
39 double bw;
40 double z1, z2, z3;
41 double w0, w1, w2;
42};
43
44 static inline void spa_dll_init(struct spa_dll *dll)
45{
46 dll->bw = 0.0;
47 dll->z1 = dll->z2 = dll->z3 = 0.0;
48}
49
50static inline void spa_dll_set_bw(struct spa_dll *dll, double bw, unsigned period, unsigned rate)
51{
52 double w = 2 * M_PI * bw * period / rate;
53 dll->w0 = 1.0 - exp (-20.0 * w);
54 dll->w1 = w * 1.5 / period;
55 dll->w2 = w / 1.5;
56 dll->bw = bw;
57}
58
59static inline double spa_dll_update(struct spa_dll *dll, double err)
60{
61 dll->z1 += dll->w0 * (dll->w1 * err - dll->z1);
62 dll->z2 += dll->w0 * (dll->z1 - dll->z2);
63 dll->z3 += dll->w2 * dll->z2;
64 return 1.0 - (dll->z2 + dll->z3);
65}
66
67#ifdef __cplusplus
68} /* extern "C" */
69#endif
70
71#endif /* SPA_DLL_H */
spa_dll
Definition: dll.h:44
spa_dll::z2
double z2
Definition: dll.h:46
spa_dll::z1
double z1
Definition: dll.h:46
spa_dll::w2
double w2
Definition: dll.h:47
spa_dll::z3
double z3
Definition: dll.h:46
spa_dll::w0
double w0
Definition: dll.h:47
spa_dll::bw
double bw
Definition: dll.h:45
spa_dll::w1
double w1
Definition: dll.h:47