* GOVERNED BY A BSD-STYLE SOURCE LICENSE INCLUDED WITH THIS SOURCE *
* IN 'COPYING'. PLEASE READ THESE TERMS BEFORE DISTRIBUTING. *
* *
- * THE OggVorbis SOURCE CODE IS (C) COPYRIGHT 1994-2007 *
- * by the Xiph.Org Foundation http://www.xiph.org/ *
+ * THE OggVorbis SOURCE CODE IS (C) COPYRIGHT 1994-2009 *
+ * by the Xiph.Org Foundation https://xiph.org/ *
* *
********************************************************************
function: normalized modified discrete cosine transform
power of two length transform only [64 <= n ]
- last mod: $Id$
Original algorithm adapted long ago from _The use of multirate filter
banks for coding of high quality digital audio_, by T. Sporer,
void mdct_init(mdct_lookup *lookup,int n){
int *bitrev=_ogg_malloc(sizeof(*bitrev)*(n/4));
DATA_TYPE *T=_ogg_malloc(sizeof(*T)*(n+n/4));
-
+
int i;
int n2=n>>1;
int log2n=lookup->log2n=rint(log((float)n)/log(2.f));
x[6] = r0 + r2;
x[4] = r0 - r2;
-
+
r0 = x[5] - x[1];
r2 = x[7] - x[3];
x[0] = r1 + r0;
x[2] = r1 - r0;
-
+
r0 = x[5] + x[1];
r1 = x[7] + x[3];
x[3] = r2 + r3;
x[1] = r2 - r3;
x[7] = r1 + r0;
x[5] = r1 - r0;
-
+
}
/* 16 point butterfly (in place, 4 register) */
REG_TYPE r0 = x[30] - x[14];
REG_TYPE r1 = x[31] - x[15];
- x[30] += x[14];
+ x[30] += x[14];
x[31] += x[15];
- x[14] = r0;
+ x[14] = r0;
x[15] = r1;
- r0 = x[28] - x[12];
+ r0 = x[28] - x[12];
r1 = x[29] - x[13];
- x[28] += x[12];
+ x[28] += x[12];
x[29] += x[13];
x[12] = MULT_NORM( r0 * cPI1_8 - r1 * cPI3_8 );
x[13] = MULT_NORM( r0 * cPI3_8 + r1 * cPI1_8 );
STIN void mdct_butterfly_first(DATA_TYPE *T,
DATA_TYPE *x,
int points){
-
+
DATA_TYPE *x1 = x + points - 8;
DATA_TYPE *x2 = x + (points>>1) - 8;
REG_TYPE r0;
REG_TYPE r1;
do{
-
+
r0 = x1[6] - x2[6];
r1 = x1[7] - x2[7];
x1[6] += x2[6];
x1[7] += x2[7];
x2[6] = MULT_NORM(r1 * T[1] + r0 * T[0]);
x2[7] = MULT_NORM(r1 * T[0] - r0 * T[1]);
-
+
r0 = x1[4] - x2[4];
r1 = x1[5] - x2[5];
x1[4] += x2[4];
x1[5] += x2[5];
x2[4] = MULT_NORM(r1 * T[5] + r0 * T[4]);
x2[5] = MULT_NORM(r1 * T[4] - r0 * T[5]);
-
+
r0 = x1[2] - x2[2];
r1 = x1[3] - x2[3];
x1[2] += x2[2];
x1[3] += x2[3];
x2[2] = MULT_NORM(r1 * T[9] + r0 * T[8]);
x2[3] = MULT_NORM(r1 * T[8] - r0 * T[9]);
-
+
r0 = x1[0] - x2[0];
r1 = x1[1] - x2[1];
x1[0] += x2[0];
x1[1] += x2[1];
x2[0] = MULT_NORM(r1 * T[13] + r0 * T[12]);
x2[1] = MULT_NORM(r1 * T[12] - r0 * T[13]);
-
+
x1-=8;
x2-=8;
T+=16;
DATA_TYPE *x,
int points,
int trigint){
-
+
DATA_TYPE *x1 = x + points - 8;
DATA_TYPE *x2 = x + (points>>1) - 8;
REG_TYPE r0;
REG_TYPE r1;
do{
-
+
r0 = x1[6] - x2[6];
r1 = x1[7] - x2[7];
x1[6] += x2[6];
x1[7] += x2[7];
x2[6] = MULT_NORM(r1 * T[1] + r0 * T[0]);
x2[7] = MULT_NORM(r1 * T[0] - r0 * T[1]);
-
+
T+=trigint;
-
+
r0 = x1[4] - x2[4];
r1 = x1[5] - x2[5];
x1[4] += x2[4];
x1[5] += x2[5];
x2[4] = MULT_NORM(r1 * T[1] + r0 * T[0]);
x2[5] = MULT_NORM(r1 * T[0] - r0 * T[1]);
-
+
T+=trigint;
-
+
r0 = x1[2] - x2[2];
r1 = x1[3] - x2[3];
x1[2] += x2[2];
x1[3] += x2[3];
x2[2] = MULT_NORM(r1 * T[1] + r0 * T[0]);
x2[3] = MULT_NORM(r1 * T[0] - r0 * T[1]);
-
+
T+=trigint;
-
+
r0 = x1[0] - x2[0];
r1 = x1[1] - x2[1];
x1[0] += x2[0];
STIN void mdct_butterflies(mdct_lookup *init,
DATA_TYPE *x,
int points){
-
+
DATA_TYPE *T=init->trig;
int stages=init->log2n-5;
int i,j;
-
+
if(--stages>0){
mdct_butterfly_first(T,x,points);
}
}
}
-STIN void mdct_bitreverse(mdct_lookup *init,
+STIN void mdct_bitreverse(mdct_lookup *init,
DATA_TYPE *x){
int n = init->n;
int *bit = init->bitrev;
r0 = HALVE(x0[1] + x1[1]);
r1 = HALVE(x0[0] - x1[0]);
-
+
w0[0] = r0 + r2;
w1[2] = r0 - r2;
w0[1] = r1 + r3;
r0 = HALVE(x0[1] + x1[1]);
r1 = HALVE(x0[0] - x1[0]);
-
+
w0[2] = r0 + r2;
w1[0] = r0 - r2;
w0[3] = r1 + r3;
DATA_TYPE *oX2=out+n2+n4;
DATA_TYPE *iX =out;
T =init->trig+n2;
-
+
do{
oX1-=4;
/* rotate */
/* window + rotate + step 1 */
-
+
REG_TYPE r0;
REG_TYPE r1;
DATA_TYPE *x0=in+n2+n4;
DATA_TYPE *x1=x0+1;
DATA_TYPE *T=init->trig+n2;
-
+
int i=0;
-
+
for(i=0;i<n8;i+=2){
x0 -=4;
T-=2;
r0= x0[2] + x1[0];
- r1= x0[0] + x1[2];
+ r1= x0[0] + x1[2];
w2[i]= MULT_NORM(r1*T[1] + r0*T[0]);
w2[i+1]= MULT_NORM(r1*T[0] - r0*T[1]);
x1 +=4;
}
x1=in+1;
-
+
for(;i<n2-n8;i+=2){
T-=2;
x0 -=4;
r0= x0[2] - x1[0];
- r1= x0[0] - x1[2];
+ r1= x0[0] - x1[2];
w2[i]= MULT_NORM(r1*T[1] + r0*T[0]);
w2[i+1]= MULT_NORM(r1*T[0] - r0*T[1]);
x1 +=4;
}
-
+
x0=in+n;
for(;i<n2;i+=2){
T-=2;
x0 -=4;
r0= -x0[2] - x1[0];
- r1= -x0[0] - x1[2];
+ r1= -x0[0] - x1[2];
w2[i]= MULT_NORM(r1*T[1] + r0*T[0]);
w2[i+1]= MULT_NORM(r1*T[0] - r0*T[1]);
x1 +=4;
T+=2;
}
}
-