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/* $OpenBSD: dsp.h,v 1.12 2022/12/26 19:16:03 jmc Exp $ */
/*
* Copyright (c) 2012 Alexandre Ratchov <alex@caoua.org>
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
#ifndef DSP_H
#define DSP_H
#include <sys/types.h>
#include "defs.h"
/*
* Samples are numbers in the interval [-1, 1[, note that 1, the upper
* boundary is excluded. We represent them as signed fixed point numbers
* of ADATA_BITS. We also assume that 2^(ADATA_BITS - 1) fits in a int.
*/
#define ADATA_BITS 24
#define ADATA_LE (BYTE_ORDER == LITTLE_ENDIAN)
#define ADATA_UNIT (1 << (ADATA_BITS - 1))
#define ADATA_MUL(x,y) \
((int)(((long long)(x) * (long long)(y)) >> (ADATA_BITS - 1)))
typedef int adata_t;
/*
* The FIR is sampled and stored in a table of fixed-point numbers
* with 23 fractional bits. For convenience, we use the same fixed-point
* numbers to represent time and to walk through the table.
*/
#define RESAMP_BITS 23
#define RESAMP_UNIT (1 << RESAMP_BITS)
/*
* Filter window length (the time unit is RESAMP_UNIT)
*/
#define RESAMP_LENGTH (8 * RESAMP_UNIT)
/*
* Time between samples of the FIR (the time unit is RESAMP_UNIT)
*/
#define RESAMP_STEP_BITS (RESAMP_BITS - 6)
#define RESAMP_STEP (1 << RESAMP_STEP_BITS)
/*
* Maximum downsample/upsample ratio we support, must be a power of two.
* The ratio between the max and the min sample rates is 192kHz / 4kHz = 48,
* so we can use 64
*/
#define RESAMP_RATIO 64
/*
* Maximum size of the encoding string (the longest possible
* encoding is ``s24le3msb'').
*/
#define ENCMAX 10
/*
* Default bytes per sample for the given bits per sample.
*/
#define APARAMS_BPS(bits) (((bits) <= 8) ? 1 : (((bits) <= 16) ? 2 : 4))
struct aparams {
unsigned int bps; /* bytes per sample */
unsigned int bits; /* actually used bits */
unsigned int le; /* 1 if little endian, else be */
unsigned int sig; /* 1 if signed, 0 if unsigned */
unsigned int msb; /* 1 if msb justified, else lsb */
};
struct resamp {
#define RESAMP_NCTX (RESAMP_LENGTH / RESAMP_UNIT * RESAMP_RATIO)
unsigned int ctx_start;
adata_t ctx[NCHAN_MAX * RESAMP_NCTX];
int filt_cutoff, filt_step;
unsigned int iblksz, oblksz;
int nch;
};
struct conv {
int bfirst; /* bytes to skip at startup */
unsigned int bps; /* bytes per sample */
unsigned int shift; /* shift to get 32bit MSB */
unsigned int bias; /* bias of unsigned samples */
int bnext; /* to reach the next byte */
int snext; /* to reach the next sample */
int nch;
};
struct cmap {
int istart;
int inext;
int onext;
int ostart;
int nch;
};
#define MIDI_TO_ADATA(m) (aparams_ctltovol[m] << (ADATA_BITS - 16))
extern const int aparams_ctltovol[128];
void aparams_init(struct aparams *);
void aparams_log(struct aparams *);
int aparams_strtoenc(struct aparams *, char *);
int aparams_enctostr(struct aparams *, char *);
int aparams_native(struct aparams *);
void resamp_do(struct resamp *, adata_t *, adata_t *, int);
void resamp_init(struct resamp *, unsigned int, unsigned int, int);
void enc_do(struct conv *, unsigned char *, unsigned char *, int);
void enc_sil_do(struct conv *, unsigned char *, int);
void enc_init(struct conv *, struct aparams *, int);
void dec_do(struct conv *, unsigned char *, unsigned char *, int);
void dec_init(struct conv *, struct aparams *, int);
void cmap_add(struct cmap *, void *, void *, int, int);
void cmap_copy(struct cmap *, void *, void *, int, int);
void cmap_init(struct cmap *, int, int, int, int, int, int, int, int);
#endif /* !defined(DSP_H) */
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