Nyaaori/rockbox
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity
rockbox/apps/codecs/demac/libdemac/predictor.c

271 lines
9.3 KiB
C
Raw Blame History

/*
libdemac - A Monkey's Audio decoder
$Id$
Copyright (C) Dave Chapman 2007
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110, USA
*/
#include <inttypes.h>
#include <string.h>
#include "parser.h"
#include "predictor.h"
#include "demac_config.h"
/* Return 0 if x is zero, -1 if x is positive, 1 if x is negative */
#define SIGN(x) (x) ? (((x) > 0) ? -1 : 1) : 0
static const int32_t initial_coeffs[4] = {
360, 317, -109, 98
};
#define YDELAYA (18 + PREDICTOR_ORDER*4)
#define YDELAYB (18 + PREDICTOR_ORDER*3)
#define XDELAYA (18 + PREDICTOR_ORDER*2)
#define XDELAYB (18 + PREDICTOR_ORDER)
#define YADAPTCOEFFSA (18)
#define XADAPTCOEFFSA (14)
#define YADAPTCOEFFSB (10)
#define XADAPTCOEFFSB (5)
void init_predictor_decoder(struct predictor_t* p)
{
/* Zero the history buffers */
memset(p->historybuffer, 0, PREDICTOR_SIZE * sizeof(int32_t));
p->buf = p->historybuffer;
/* Initialise and zero the co-efficients */
memcpy(p->YcoeffsA, initial_coeffs, sizeof(initial_coeffs));
memcpy(p->XcoeffsA, initial_coeffs, sizeof(initial_coeffs));
memset(p->YcoeffsB, 0, sizeof(p->YcoeffsB));
memset(p->XcoeffsB, 0, sizeof(p->XcoeffsB));
p->YfilterA = 0;
p->YfilterB = 0;
p->YlastA = 0;
p->XfilterA = 0;
p->XfilterB = 0;
p->XlastA = 0;
}
#if !defined(CPU_ARM) && !defined(CPU_COLDFIRE)
void ICODE_ATTR_DEMAC predictor_decode_stereo(struct predictor_t* p,
int32_t* decoded0,
int32_t* decoded1,
int count)
{
int32_t predictionA, predictionB;
while (LIKELY(count--))
{
/* Predictor Y */
p->buf[YDELAYA] = p->YlastA;
p->buf[YADAPTCOEFFSA] = SIGN(p->buf[YDELAYA]);
p->buf[YDELAYA-1] = p->buf[YDELAYA] - p->buf[YDELAYA-1];
p->buf[YADAPTCOEFFSA-1] = SIGN(p->buf[YDELAYA-1]);
predictionA = (p->buf[YDELAYA] * p->YcoeffsA[0]) +
(p->buf[YDELAYA-1] * p->YcoeffsA[1]) +
(p->buf[YDELAYA-2] * p->YcoeffsA[2]) +
(p->buf[YDELAYA-3] * p->YcoeffsA[3]);
/* Apply a scaled first-order filter compression */
p->buf[YDELAYB] = p->XfilterA - ((p->YfilterB * 31) >> 5);
p->buf[YADAPTCOEFFSB] = SIGN(p->buf[YDELAYB]);
p->YfilterB = p->XfilterA;
p->buf[YDELAYB-1] = p->buf[YDELAYB] - p->buf[YDELAYB-1];
p->buf[YADAPTCOEFFSB-1] = SIGN(p->buf[YDELAYB-1]);
predictionB = (p->buf[YDELAYB] * p->YcoeffsB[0]) +
(p->buf[YDELAYB-1] * p->YcoeffsB[1]) +
(p->buf[YDELAYB-2] * p->YcoeffsB[2]) +
(p->buf[YDELAYB-3] * p->YcoeffsB[3]) +
(p->buf[YDELAYB-4] * p->YcoeffsB[4]);
p->YlastA = *decoded0 + ((predictionA + (predictionB >> 1)) >> 10);
p->YfilterA = p->YlastA + ((p->YfilterA * 31) >> 5);
/* Predictor X */
p->buf[XDELAYA] = p->XlastA;
p->buf[XADAPTCOEFFSA] = SIGN(p->buf[XDELAYA]);
p->buf[XDELAYA-1] = p->buf[XDELAYA] - p->buf[XDELAYA-1];
p->buf[XADAPTCOEFFSA-1] = SIGN(p->buf[XDELAYA-1]);
predictionA = (p->buf[XDELAYA] * p->XcoeffsA[0]) +
(p->buf[XDELAYA-1] * p->XcoeffsA[1]) +
(p->buf[XDELAYA-2] * p->XcoeffsA[2]) +
(p->buf[XDELAYA-3] * p->XcoeffsA[3]);
/* Apply a scaled first-order filter compression */
p->buf[XDELAYB] = p->YfilterA - ((p->XfilterB * 31) >> 5);
p->buf[XADAPTCOEFFSB] = SIGN(p->buf[XDELAYB]);
p->XfilterB = p->YfilterA;
p->buf[XDELAYB-1] = p->buf[XDELAYB] - p->buf[XDELAYB-1];
p->buf[XADAPTCOEFFSB-1] = SIGN(p->buf[XDELAYB-1]);
predictionB = (p->buf[XDELAYB] * p->XcoeffsB[0]) +
(p->buf[XDELAYB-1] * p->XcoeffsB[1]) +
(p->buf[XDELAYB-2] * p->XcoeffsB[2]) +
(p->buf[XDELAYB-3] * p->XcoeffsB[3]) +
(p->buf[XDELAYB-4] * p->XcoeffsB[4]);
p->XlastA = *decoded1 + ((predictionA + (predictionB >> 1)) >> 10);
p->XfilterA = p->XlastA + ((p->XfilterA * 31) >> 5);
if (LIKELY(*decoded0 != 0))
{
if (*decoded0 > 0)
{
p->YcoeffsA[0] -= p->buf[YADAPTCOEFFSA];
p->YcoeffsA[1] -= p->buf[YADAPTCOEFFSA-1];
p->YcoeffsA[2] -= p->buf[YADAPTCOEFFSA-2];
p->YcoeffsA[3] -= p->buf[YADAPTCOEFFSA-3];
p->YcoeffsB[0] -= p->buf[YADAPTCOEFFSB];
p->YcoeffsB[1] -= p->buf[YADAPTCOEFFSB-1];
p->YcoeffsB[2] -= p->buf[YADAPTCOEFFSB-2];
p->YcoeffsB[3] -= p->buf[YADAPTCOEFFSB-3];
p->YcoeffsB[4] -= p->buf[YADAPTCOEFFSB-4];
}
else
{
p->YcoeffsA[0] += p->buf[YADAPTCOEFFSA];
p->YcoeffsA[1] += p->buf[YADAPTCOEFFSA-1];
p->YcoeffsA[2] += p->buf[YADAPTCOEFFSA-2];
p->YcoeffsA[3] += p->buf[YADAPTCOEFFSA-3];
p->YcoeffsB[0] += p->buf[YADAPTCOEFFSB];
p->YcoeffsB[1] += p->buf[YADAPTCOEFFSB-1];
p->YcoeffsB[2] += p->buf[YADAPTCOEFFSB-2];
p->YcoeffsB[3] += p->buf[YADAPTCOEFFSB-3];
p->YcoeffsB[4] += p->buf[YADAPTCOEFFSB-4];
}
}
*(decoded0++) = p->YfilterA;
if (LIKELY(*decoded1 != 0))
{
if (*decoded1 > 0)
{
p->XcoeffsA[0] -= p->buf[XADAPTCOEFFSA];
p->XcoeffsA[1] -= p->buf[XADAPTCOEFFSA-1];
p->XcoeffsA[2] -= p->buf[XADAPTCOEFFSA-2];
p->XcoeffsA[3] -= p->buf[XADAPTCOEFFSA-3];
p->XcoeffsB[0] -= p->buf[XADAPTCOEFFSB];
p->XcoeffsB[1] -= p->buf[XADAPTCOEFFSB-1];
p->XcoeffsB[2] -= p->buf[XADAPTCOEFFSB-2];
p->XcoeffsB[3] -= p->buf[XADAPTCOEFFSB-3];
p->XcoeffsB[4] -= p->buf[XADAPTCOEFFSB-4];
}
else
{
p->XcoeffsA[0] += p->buf[XADAPTCOEFFSA];
p->XcoeffsA[1] += p->buf[XADAPTCOEFFSA-1];
p->XcoeffsA[2] += p->buf[XADAPTCOEFFSA-2];
p->XcoeffsA[3] += p->buf[XADAPTCOEFFSA-3];
p->XcoeffsB[0] += p->buf[XADAPTCOEFFSB];
p->XcoeffsB[1] += p->buf[XADAPTCOEFFSB-1];
p->XcoeffsB[2] += p->buf[XADAPTCOEFFSB-2];
p->XcoeffsB[3] += p->buf[XADAPTCOEFFSB-3];
p->XcoeffsB[4] += p->buf[XADAPTCOEFFSB-4];
}
}
*(decoded1++) = p->XfilterA;
/* Combined */
p->buf++;
/* Have we filled the history buffer? */
if (UNLIKELY(p->buf == p->historybuffer + PREDICTOR_HISTORY_SIZE)) {
memmove(p->historybuffer, p->buf,
PREDICTOR_SIZE * sizeof(int32_t));
p->buf = p->historybuffer;
}
}
}
void ICODE_ATTR_DEMAC predictor_decode_mono(struct predictor_t* p,
int32_t* decoded0,
int count)
{
int32_t predictionA, currentA, A;
currentA = p->YlastA;
while (LIKELY(count--))
{
A = *decoded0;
p->buf[YDELAYA] = currentA;
p->buf[YDELAYA-1] = p->buf[YDELAYA] - p->buf[YDELAYA-1];
predictionA = (p->buf[YDELAYA] * p->YcoeffsA[0]) +
(p->buf[YDELAYA-1] * p->YcoeffsA[1]) +
(p->buf[YDELAYA-2] * p->YcoeffsA[2]) +
(p->buf[YDELAYA-3] * p->YcoeffsA[3]);
currentA = A + (predictionA >> 10);
p->buf[YADAPTCOEFFSA] = SIGN(p->buf[YDELAYA]);
p->buf[YADAPTCOEFFSA-1] = SIGN(p->buf[YDELAYA-1]);
if (LIKELY(A != 0))
{
if (A > 0)
{
p->YcoeffsA[0] -= p->buf[YADAPTCOEFFSA];
p->YcoeffsA[1] -= p->buf[YADAPTCOEFFSA-1];
p->YcoeffsA[2] -= p->buf[YADAPTCOEFFSA-2];
p->YcoeffsA[3] -= p->buf[YADAPTCOEFFSA-3];
}
else
{
p->YcoeffsA[0] += p->buf[YADAPTCOEFFSA];
p->YcoeffsA[1] += p->buf[YADAPTCOEFFSA-1];
p->YcoeffsA[2] += p->buf[YADAPTCOEFFSA-2];
p->YcoeffsA[3] += p->buf[YADAPTCOEFFSA-3];
}
}
p->buf++;
/* Have we filled the history buffer? */
if (UNLIKELY(p->buf == p->historybuffer + PREDICTOR_HISTORY_SIZE)) {
memmove(p->historybuffer, p->buf,
PREDICTOR_SIZE * sizeof(int32_t));
p->buf = p->historybuffer;
}
p->YfilterA = currentA + ((p->YfilterA * 31) >> 5);
*(decoded0++) = p->YfilterA;
}
p->YlastA = currentA;
}
#endif
Reference in a new issue View git blame Copy permalink