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asterisk/codecs/mp3/src/icdct.c
Mark Spencer 75b660551a Version 0.1.1 from FTP 
git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@95 65c4cc65-6c06-0410-ace0-fbb531ad65f3
1999-12-07 05:45:48 +00:00

384 lines
10 KiB
C
Executable File
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/*____________________________________________________________________________
FreeAmp - The Free MP3 Player
MP3 Decoder originally Copyright (C) 1995-1997 Xing Technology
Corp. http://www.xingtech.com
Portions Copyright (C) 1998 EMusic.com
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., 675 Mass Ave, Cambridge, MA 02139, USA.
$Id$
____________________________________________________________________________*/
/**** icdct.c ***************************************************
MPEG audio decoder, dct
portable C integer dct
mod 1/8/97 warnings
******************************************************************/
#include <stdlib.h>
#include <stdio.h>
#include <float.h>
#include <math.h>
#include "itype.h"
/*-------------------------------------------------------------------*/
static DCTCOEF coef32[32]; /* 32 pt dct coefs */
#define forward_bf idx_forward_bf
/*--- #define forward_bf ptr_forward_bf ---*/
/*------------------------------------------------------------*/
DCTCOEF *i_dct_coef_addr()
{
return coef32;
}
/*------------------------------------------------------------*/
static void idx_forward_bf(int m, int n, INT32 x[], INT32 f[], DCTCOEF coef[])
{
int i, j, n2;
int p, q, p0, k;
p0 = 0;
n2 = n >> 1;
for (i = 0; i < m; i++, p0 += n)
{
k = 0;
p = p0;
q = p + n - 1;
for (j = 0; j < n2; j++, p++, q--, k++)
{
f[p] = x[p] + x[q];
f[n2 + p] = ((x[p] - x[q]) * coef[k]) >> DCTBITS;
}
}
}
/*------------------------------------------------------------*/
/*--
static void ptr_forward_bf(int m, int n, INT32 x[], INT32 f[], DCTCOEF coef[])
{
int i, j, n2;
DCTCOEF *c;
INT32 *y;
n2 = n >> 1;
for(i=0; i<m; i++) {
c = coef;
y = x+n;
for(j=0; j<n2; j++) {
*f = *x + *--y;
*((f++)+n2) = ( (*x++ - *y) * (*c++) ) >> DCTBITS;
}
f+=n2;
x+=n2;
}
}
---*/
/*------------------------------------------------------------*/
static void forward_bfm(int m, INT32 x[], INT32 f[])
{
int i;
int p;
/*--- special case last fwd stage ----*/
for (p = 0, i = 0; i < m; i++, p += 2)
{
f[p] = x[p] + x[p + 1];
f[p + 1] = ((x[p] - x[p + 1]) * coef32[30]) >> DCTBITS;
}
}
/*------------------------------------------------------------*/
static void back_bf(int m, int n, INT32 x[], INT32 f[])
{
int i, j, n2, n21;
int p, q, p0;
p0 = 0;
n2 = n >> 1;
n21 = n2 - 1;
for (i = 0; i < m; i++, p0 += n)
{
p = p0;
q = p0;
for (j = 0; j < n2; j++, p += 2, q++)
f[p] = x[q];
p = p0 + 1;
for (j = 0; j < n21; j++, p += 2, q++)
f[p] = x[q] + x[q + 1];
f[p] = x[q];
}
}
/*------------------------------------------------------------*/
static void back_bf0(int n, INT32 x[], WININT f[])
{
int p, q;
n--;
#if DCTSATURATE
for (p = 0, q = 0; p < n; p += 2, q++)
{
tmp = x[q];
if (tmp > 32767)
tmp = 32767;
else if (tmp < -32768)
tmp = -32768;
f[p] = tmp;
}
for (p = 1; q < n; p += 2, q++)
{
tmp = x[q] + x[q + 1];
if (tmp > 32767)
tmp = 32767;
else if (tmp < -32768)
tmp = -32768;
f[p] = tmp;
}
tmp = x[q];
if (tmp > 32767)
tmp = 32767;
else if (tmp < -32768)
tmp = -32768;
f[p] = tmp;
#else
for (p = 0, q = 0; p < n; p += 2, q++)
f[p] = x[q];
for (p = 1; q < n; p += 2, q++)
f[p] = x[q] + x[q + 1];
f[p] = x[q];
#endif
}
/*------------------------------------------------------------*/
void i_dct32(SAMPLEINT x[], WININT c[])
{
INT32 a[32]; /* ping pong buffers */
INT32 b[32];
int p, q;
/* special first stage */
for (p = 0, q = 31; p < 16; p++, q--)
{
a[p] = (INT32) x[p] + x[q];
a[16 + p] = (coef32[p] * ((INT32) x[p] - x[q])) >> DCTBITS;
}
forward_bf(2, 16, a, b, coef32 + 16);
forward_bf(4, 8, b, a, coef32 + 16 + 8);
forward_bf(8, 4, a, b, coef32 + 16 + 8 + 4);
forward_bfm(16, b, a);
back_bf(8, 4, a, b);
back_bf(4, 8, b, a);
back_bf(2, 16, a, b);
back_bf0(32, b, c);
}
/*------------------------------------------------------------*/
void i_dct32_dual(SAMPLEINT x[], WININT c[])
{
INT32 a[32]; /* ping pong buffers */
INT32 b[32];
int p, pp, qq;
/* special first stage for dual chan (interleaved x) */
pp = 0;
qq = 2 * 31;
for (p = 0; p < 16; p++, pp += 2, qq -= 2)
{
a[p] = (INT32) x[pp] + x[qq];
a[16 + p] = (coef32[p] * ((INT32) x[pp] - x[qq])) >> DCTBITS;
}
forward_bf(2, 16, a, b, coef32 + 16);
forward_bf(4, 8, b, a, coef32 + 16 + 8);
forward_bf(8, 4, a, b, coef32 + 16 + 8 + 4);
forward_bfm(16, b, a);
back_bf(8, 4, a, b);
back_bf(4, 8, b, a);
back_bf(2, 16, a, b);
back_bf0(32, b, c);
}
/*---------------convert dual to mono------------------------------*/
void i_dct32_dual_mono(SAMPLEINT x[], WININT c[])
{
INT32 a[32]; /* ping pong buffers */
INT32 b[32];
INT32 t1, t2;
int p, pp, qq;
/* special first stage */
pp = 0;
qq = 2 * 31;
for (p = 0; p < 16; p++, pp += 2, qq -= 2)
{
t1 = ((INT32) x[pp] + x[pp + 1]);
t2 = ((INT32) x[qq] + x[qq + 1]);
a[p] = (t1 + t2) >> 1;
a[16 + p] = coef32[p] * (t1 - t2) >> (DCTBITS + 1);
}
forward_bf(2, 16, a, b, coef32 + 16);
forward_bf(4, 8, b, a, coef32 + 16 + 8);
forward_bf(8, 4, a, b, coef32 + 16 + 8 + 4);
forward_bfm(16, b, a);
back_bf(8, 4, a, b);
back_bf(4, 8, b, a);
back_bf(2, 16, a, b);
back_bf0(32, b, c);
}
/*------------------------------------------------------------*/
/*---------------- 16 pt dct -------------------------------*/
void i_dct16(SAMPLEINT x[], WININT c[])
{
INT32 a[16]; /* ping pong buffers */
INT32 b[16];
int p, q;
/* special first stage (drop highest sb) */
a[0] = x[0];
a[8] = (a[0] * coef32[16]) >> DCTBITS;
for (p = 1, q = 14; p < 8; p++, q--)
{
a[p] = (INT32) x[p] + x[q];
a[8 + p] = (((INT32) x[p] - x[q]) * coef32[16 + p]) >> DCTBITS;
}
forward_bf(2, 8, a, b, coef32 + 16 + 8);
forward_bf(4, 4, b, a, coef32 + 16 + 8 + 4);
forward_bfm(8, a, b);
back_bf(4, 4, b, a);
back_bf(2, 8, a, b);
back_bf0(16, b, c);
}
/*------------------------------------------------------------*/
/*---------------- 16 pt dct dual chan---------------------*/
void i_dct16_dual(SAMPLEINT x[], WININT c[])
{
int p, pp, qq;
INT32 a[16]; /* ping pong buffers */
INT32 b[16];
/* special first stage for interleaved input */
a[0] = x[0];
a[8] = (coef32[16] * a[0]) >> DCTBITS;
pp = 2;
qq = 2 * 14;
for (p = 1; p < 8; p++, pp += 2, qq -= 2)
{
a[p] = (INT32) x[pp] + x[qq];
a[8 + p] = (coef32[16 + p] * ((INT32) x[pp] - x[qq])) >> DCTBITS;
}
forward_bf(2, 8, a, b, coef32 + 16 + 8);
forward_bf(4, 4, b, a, coef32 + 16 + 8 + 4);
forward_bfm(8, a, b);
back_bf(4, 4, b, a);
back_bf(2, 8, a, b);
back_bf0(16, b, c);
}
/*------------------------------------------------------------*/
/*---------------- 16 pt dct dual to mono-------------------*/
void i_dct16_dual_mono(SAMPLEINT x[], WININT c[])
{
INT32 a[16]; /* ping pong buffers */
INT32 b[16];
INT32 t1, t2;
int p, pp, qq;
/* special first stage */
a[0] = ((INT32) x[0] + x[1]) >> 1;
a[8] = (coef32[16] * a[0]) >> DCTBITS;
pp = 2;
qq = 2 * 14;
for (p = 1; p < 8; p++, pp += 2, qq -= 2)
{
t1 = (INT32) x[pp] + x[pp + 1];
t2 = (INT32) x[qq] + x[qq + 1];
a[p] = (t1 + t2) >> 1;
a[8 + p] = (coef32[16 + p] * (t1 - t2)) >> (DCTBITS + 1);
}
forward_bf(2, 8, a, b, coef32 + 16 + 8);
forward_bf(4, 4, b, a, coef32 + 16 + 8 + 4);
forward_bfm(8, a, b);
back_bf(4, 4, b, a);
back_bf(2, 8, a, b);
back_bf0(16, b, c);
}
/*------------------------------------------------------------*/
/*---------------- 8 pt dct -------------------------------*/
void i_dct8(SAMPLEINT x[], WININT c[])
{
int p, q;
INT32 a[8]; /* ping pong buffers */
INT32 b[8];
/* special first stage */
for (p = 0, q = 7; p < 4; p++, q--)
{
b[p] = (INT32) x[p] + x[q];
b[4 + p] = (coef32[16 + 8 + p] * ((INT32) x[p] - x[q])) >> DCTBITS;
}
forward_bf(2, 4, b, a, coef32 + 16 + 8 + 4);
forward_bfm(4, a, b);
back_bf(2, 4, b, a);
back_bf0(8, a, c);
}
/*------------------------------------------------------------*/
/*---------------- 8 pt dct dual chan---------------------*/
void i_dct8_dual(SAMPLEINT x[], WININT c[])
{
int p, pp, qq;
INT32 a[8]; /* ping pong buffers */
INT32 b[8];
/* special first stage for interleaved input */
for (p = 0, pp = 0, qq = 14; p < 4; p++, pp += 2, qq -= 2)
{
b[p] = (INT32) x[pp] + x[qq];
b[4 + p] = (coef32[16 + 8 + p] * ((INT32) x[pp] - x[qq])) >> DCTBITS;
}
forward_bf(2, 4, b, a, coef32 + 16 + 8 + 4);
forward_bfm(4, a, b);
back_bf(2, 4, b, a);
back_bf0(8, a, c);
}
/*------------------------------------------------------------*/
/*---------------- 8 pt dct dual to mono---------------------*/
void i_dct8_dual_mono(SAMPLEINT x[], WININT c[])
{
int p, pp, qq;
INT32 a[8]; /* ping pong buffers */
INT32 b[8];
INT32 t1, t2;
/* special first stage */
for (p = 0, pp = 0, qq = 14; p < 4; p++, pp += 2, qq -= 2)
{
t1 = (INT32) x[pp] + x[pp + 1];
t2 = (INT32) x[qq] + x[qq + 1];
b[p] = (t1 + t2) >> 1;
b[4 + p] = (coef32[16 + 8 + p] * (t1 - t2)) >> (DCTBITS + 1);
}
forward_bf(2, 4, b, a, coef32 + 16 + 8 + 4);
forward_bfm(4, a, b);
back_bf(2, 4, b, a);
back_bf0(8, a, c);
}
/*------------------------------------------------------------*/
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