1/*	$OpenBSD: dsp.h,v 1.12 2024/04/22 12:32:51 ratchov Exp $	*/
2/*
3 * Copyright (c) 2012 Alexandre Ratchov <alex@caoua.org>
4 *
5 * Permission to use, copy, modify, and distribute this software for any
6 * purpose with or without fee is hereby granted, provided that the above
7 * copyright notice and this permission notice appear in all copies.
8 *
9 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
10 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
11 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
12 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
13 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
14 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
15 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
16 */
17#ifndef DSP_H
18#define DSP_H
19
20#include <sys/types.h>
21#include "defs.h"
22
23/*
24 * Samples are numbers in the interval [-1, 1[, note that 1, the upper
25 * boundary is excluded. We represent them as signed fixed point numbers
26 * of ADATA_BITS. We also assume that 2^(ADATA_BITS - 1) fits in a int.
27 */
28#define ADATA_BITS			24
29#define ADATA_LE			(BYTE_ORDER == LITTLE_ENDIAN)
30#define ADATA_UNIT			(1 << (ADATA_BITS - 1))
31
32#define ADATA_MUL(x,y)		\
33	((int)(((long long)(x) * (long long)(y)) >> (ADATA_BITS - 1)))
34
35typedef int adata_t;
36
37/*
38 * The FIR is sampled and stored in a table of fixed-point numbers
39 * with 23 fractional bits. For convenience, we use the same fixed-point
40 * numbers to represent time and to walk through the table.
41 */
42#define RESAMP_BITS		23
43#define RESAMP_UNIT		(1 << RESAMP_BITS)
44
45/*
46 * Filter window length (the time unit is RESAMP_UNIT)
47 */
48#define RESAMP_LENGTH		(8 * RESAMP_UNIT)
49
50/*
51 * Time between samples of the FIR (the time unit is RESAMP_UNIT)
52 */
53#define RESAMP_STEP_BITS	(RESAMP_BITS - 6)
54#define RESAMP_STEP		(1 << RESAMP_STEP_BITS)
55
56/*
57 * Maximum downsample/upsample ratio we support, must be a power of two.
58 * The ratio between the max and the min sample rates is 192kHz / 4kHz = 48,
59 * so we can use 64
60 */
61#define RESAMP_RATIO		64
62
63/*
64 * Maximum size of the encoding string (the longest possible
65 * encoding is ``s24le3msb'').
66 */
67#define ENCMAX	10
68
69/*
70 * Default bytes per sample for the given bits per sample.
71 */
72#define APARAMS_BPS(bits) (((bits) <= 8) ? 1 : (((bits) <= 16) ? 2 : 4))
73
74struct aparams {
75	unsigned int bps;		/* bytes per sample */
76	unsigned int bits;		/* actually used bits */
77	unsigned int le;		/* 1 if little endian, else be */
78	unsigned int sig;		/* 1 if signed, 0 if unsigned */
79	unsigned int msb;		/* 1 if msb justified, else lsb */
80};
81
82struct resamp {
83#define RESAMP_NCTX	(RESAMP_LENGTH / RESAMP_UNIT * RESAMP_RATIO)
84	unsigned int ctx_start;
85	adata_t ctx[NCHAN_MAX * RESAMP_NCTX];
86	int filt_cutoff, filt_step;
87	unsigned int iblksz, oblksz;
88	int diff;
89	int nch;
90};
91
92struct conv {
93	int bfirst;			/* bytes to skip at startup */
94	unsigned int bps;		/* bytes per sample */
95	unsigned int shift;		/* shift to get 32bit MSB */
96	unsigned int bias;		/* bias of unsigned samples */
97	int bnext;			/* to reach the next byte */
98	int snext;			/* to reach the next sample */
99	int nch;
100};
101
102struct cmap {
103	int istart;
104	int inext;
105	int onext;
106	int ostart;
107	int nch;
108};
109
110#define MIDI_TO_ADATA(m)	(aparams_ctltovol[m])
111extern const int aparams_ctltovol[128];
112
113void aparams_init(struct aparams *);
114void aparams_log(struct aparams *);
115int aparams_strtoenc(struct aparams *, char *);
116int aparams_enctostr(struct aparams *, char *);
117int aparams_native(struct aparams *);
118
119void resamp_getcnt(struct resamp *, int *, int *);
120void resamp_do(struct resamp *, adata_t *, adata_t *, int, int);
121void resamp_init(struct resamp *, unsigned int, unsigned int, int);
122void enc_do(struct conv *, unsigned char *, unsigned char *, int);
123void enc_sil_do(struct conv *, unsigned char *, int);
124void enc_init(struct conv *, struct aparams *, int);
125void dec_do(struct conv *, unsigned char *, unsigned char *, int);
126void dec_do_float(struct conv *, unsigned char *, unsigned char *, int);
127void dec_do_ulaw(struct conv *, unsigned char *, unsigned char *, int, int);
128void dec_init(struct conv *, struct aparams *, int);
129void cmap_add(struct cmap *, void *, void *, int, int);
130void cmap_copy(struct cmap *, void *, void *, int, int);
131void cmap_init(struct cmap *, int, int, int, int, int, int, int, int);
132
133#endif /* !defined(DSP_H) */
134