134 lines
4.3 KiB
C
134 lines
4.3 KiB
C
/* $OpenBSD: dsp.h,v 1.12 2024/04/22 12:32:51 ratchov Exp $ */
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/*
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* Copyright (c) 2012 Alexandre Ratchov <alex@caoua.org>
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*
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* Permission to use, copy, modify, and distribute this software for any
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* purpose with or without fee is hereby granted, provided that the above
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* copyright notice and this permission notice appear in all copies.
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*
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* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
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* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
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* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
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* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
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* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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*/
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#ifndef DSP_H
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#define DSP_H
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#include <sys/types.h>
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#include "defs.h"
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/*
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* Samples are numbers in the interval [-1, 1[, note that 1, the upper
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* boundary is excluded. We represent them as signed fixed point numbers
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* of ADATA_BITS. We also assume that 2^(ADATA_BITS - 1) fits in a int.
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*/
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#define ADATA_BITS 24
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#define ADATA_LE (BYTE_ORDER == LITTLE_ENDIAN)
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#define ADATA_UNIT (1 << (ADATA_BITS - 1))
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#define ADATA_MUL(x,y) \
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((int)(((long long)(x) * (long long)(y)) >> (ADATA_BITS - 1)))
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typedef int adata_t;
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/*
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* The FIR is sampled and stored in a table of fixed-point numbers
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* with 23 fractional bits. For convenience, we use the same fixed-point
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* numbers to represent time and to walk through the table.
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*/
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#define RESAMP_BITS 23
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#define RESAMP_UNIT (1 << RESAMP_BITS)
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/*
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* Filter window length (the time unit is RESAMP_UNIT)
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*/
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#define RESAMP_LENGTH (8 * RESAMP_UNIT)
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/*
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* Time between samples of the FIR (the time unit is RESAMP_UNIT)
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*/
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#define RESAMP_STEP_BITS (RESAMP_BITS - 6)
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#define RESAMP_STEP (1 << RESAMP_STEP_BITS)
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/*
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* Maximum downsample/upsample ratio we support, must be a power of two.
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* The ratio between the max and the min sample rates is 192kHz / 4kHz = 48,
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* so we can use 64
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*/
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#define RESAMP_RATIO 64
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/*
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* Maximum size of the encoding string (the longest possible
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* encoding is ``s24le3msb'').
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*/
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#define ENCMAX 10
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/*
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* Default bytes per sample for the given bits per sample.
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*/
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#define APARAMS_BPS(bits) (((bits) <= 8) ? 1 : (((bits) <= 16) ? 2 : 4))
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struct aparams {
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unsigned int bps; /* bytes per sample */
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unsigned int bits; /* actually used bits */
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unsigned int le; /* 1 if little endian, else be */
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unsigned int sig; /* 1 if signed, 0 if unsigned */
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unsigned int msb; /* 1 if msb justified, else lsb */
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};
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struct resamp {
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#define RESAMP_NCTX (RESAMP_LENGTH / RESAMP_UNIT * RESAMP_RATIO)
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unsigned int ctx_start;
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adata_t ctx[NCHAN_MAX * RESAMP_NCTX];
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int filt_cutoff, filt_step;
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unsigned int iblksz, oblksz;
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int diff;
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int nch;
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};
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struct conv {
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int bfirst; /* bytes to skip at startup */
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unsigned int bps; /* bytes per sample */
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unsigned int shift; /* shift to get 32bit MSB */
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unsigned int bias; /* bias of unsigned samples */
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int bnext; /* to reach the next byte */
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int snext; /* to reach the next sample */
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int nch;
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};
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struct cmap {
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int istart;
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int inext;
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int onext;
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int ostart;
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int nch;
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};
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#define MIDI_TO_ADATA(m) (aparams_ctltovol[m])
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extern const int aparams_ctltovol[128];
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void aparams_init(struct aparams *);
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void aparams_log(struct aparams *);
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int aparams_strtoenc(struct aparams *, char *);
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int aparams_enctostr(struct aparams *, char *);
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int aparams_native(struct aparams *);
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void resamp_getcnt(struct resamp *, int *, int *);
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void resamp_do(struct resamp *, adata_t *, adata_t *, int, int);
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void resamp_init(struct resamp *, unsigned int, unsigned int, int);
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void enc_do(struct conv *, unsigned char *, unsigned char *, int);
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void enc_sil_do(struct conv *, unsigned char *, int);
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void enc_init(struct conv *, struct aparams *, int);
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void dec_do(struct conv *, unsigned char *, unsigned char *, int);
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void dec_do_float(struct conv *, unsigned char *, unsigned char *, int);
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void dec_do_ulaw(struct conv *, unsigned char *, unsigned char *, int, int);
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void dec_init(struct conv *, struct aparams *, int);
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void cmap_add(struct cmap *, void *, void *, int, int);
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void cmap_copy(struct cmap *, void *, void *, int, int);
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void cmap_init(struct cmap *, int, int, int, int, int, int, int, int);
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#endif /* !defined(DSP_H) */
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