* 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 1994-2002 *
- * by the XIPHOPHORUS Company http://www.xiph.org/ *
+ * THE OggVorbis SOURCE CODE IS (C) COPYRIGHT 1994-2009 *
+ * by the Xiph.Org Foundation http://www.xiph.org/ *
* *
********************************************************************
function: LSP (also called LSF) conversion routines
- last mod: $Id: lsp.c,v 1.23 2002/10/11 07:44:28 xiphmont Exp $
The LSP generation code is taken (with minimal modification and a
few bugfixes) from "On the Computation of the LSP Frequencies" by
- Joseph Rothweiler <rothwlr@altavista.net>, available at:
-
- http://www2.xtdl.com/~rothwlr/lsfpaper/lsfpage.html
+ Joseph Rothweiler (see http://www.rothweiler.us for contact info).
+ The paper is available at:
+
+ http://www.myown1.com/joe/lsf
********************************************************************/
implementation. The float lookup is likely the optimal choice on
any machine with an FPU. The integer implementation is *not* fixed
point (due to the need for a large dynamic range and thus a
- seperately tracked exponent) and thus much more complex than the
+ separately tracked exponent) and thus much more complex than the
relatively simple float implementations. It's mostly for future
work on a fully fixed point implementation for processors like the
ARM family. */
-/* undefine both for the 'old' but more precise implementation */
-#define FLOAT_LOOKUP
-#undef INT_LOOKUP
+/* define either of these (preferably FLOAT_LOOKUP) to have faster
+ but less precise implementation. */
+#undef FLOAT_LOOKUP
+#undef INT_LOOKUP
#ifdef FLOAT_LOOKUP
#include "lookup.c" /* catch this in the build system; we #include for
/* side effect: changes *lsp to cosines of lsp */
void vorbis_lsp_to_curve(float *curve,int *map,int n,int ln,float *lsp,int m,
- float amp,float ampoffset){
+ float amp,float ampoffset){
int i;
float wdel=M_PI/ln;
vorbis_fpu_control fpu;
-
+
vorbis_fpu_setround(&fpu);
for(i=0;i<m;i++)lsp[i]=vorbis_coslook(lsp[i]);
float *ftmp=lsp;
int c=m>>1;
- do{
+ while(c--){
q*=ftmp[0]-w;
p*=ftmp[1]-w;
ftmp+=2;
- }while(--c);
+ }
if(m&1){
/* odd order filter; slightly assymetric */
}
q=frexp(p+q,&qexp);
- q=vorbis_fromdBlook(amp*
- vorbis_invsqlook(q)*
- vorbis_invsq2explook(qexp+m)-
- ampoffset);
+ q=vorbis_fromdBlook(amp*
+ vorbis_invsqlook(q)*
+ vorbis_invsq2explook(qexp+m)-
+ ampoffset);
do{
curve[i++]*=q;
compilers (like gcc) that can't inline across
modules */
-static int MLOOP_1[64]={
+static const int MLOOP_1[64]={
0,10,11,11, 12,12,12,12, 13,13,13,13, 13,13,13,13,
14,14,14,14, 14,14,14,14, 14,14,14,14, 14,14,14,14,
15,15,15,15, 15,15,15,15, 15,15,15,15, 15,15,15,15,
15,15,15,15, 15,15,15,15, 15,15,15,15, 15,15,15,15,
};
-static int MLOOP_2[64]={
+static const int MLOOP_2[64]={
0,4,5,5, 6,6,6,6, 7,7,7,7, 7,7,7,7,
8,8,8,8, 8,8,8,8, 8,8,8,8, 8,8,8,8,
9,9,9,9, 9,9,9,9, 9,9,9,9, 9,9,9,9,
9,9,9,9, 9,9,9,9, 9,9,9,9, 9,9,9,9,
};
-static int MLOOP_3[8]={0,1,2,2,3,3,3,3};
+static const int MLOOP_3[8]={0,1,2,2,3,3,3,3};
/* side effect: changes *lsp to cosines of lsp */
void vorbis_lsp_to_curve(float *curve,int *map,int n,int ln,float *lsp,int m,
- float amp,float ampoffset){
+ float amp,float ampoffset){
/* 0 <= m < 256 */
for(j=3;j<m;j+=2){
if(!(shift=MLOOP_1[(pi|qi)>>25]))
- if(!(shift=MLOOP_2[(pi|qi)>>19]))
- shift=MLOOP_3[(pi|qi)>>16];
+ if(!(shift=MLOOP_2[(pi|qi)>>19]))
+ shift=MLOOP_3[(pi|qi)>>16];
qi=(qi>>shift)*labs(ilsp[j-1]-wi);
pi=(pi>>shift)*labs(ilsp[j]-wi);
qexp+=shift;
}
if(!(shift=MLOOP_1[(pi|qi)>>25]))
if(!(shift=MLOOP_2[(pi|qi)>>19]))
- shift=MLOOP_3[(pi|qi)>>16];
+ shift=MLOOP_3[(pi|qi)>>16];
/* pi,qi normalized collectively, both tracked using qexp */
qexp+=shift;
if(!(shift=MLOOP_1[(pi|qi)>>25]))
- if(!(shift=MLOOP_2[(pi|qi)>>19]))
- shift=MLOOP_3[(pi|qi)>>16];
-
+ if(!(shift=MLOOP_2[(pi|qi)>>19]))
+ shift=MLOOP_3[(pi|qi)>>16];
+
pi>>=shift;
qi>>=shift;
qexp+=shift-14*((m+1)>>1);
/* even order filter; still symmetric */
/* p*=p(1-w), q*=q(1+w), let normalization drift because it isn't
- worth tracking step by step */
-
+ worth tracking step by step */
+
pi>>=shift;
qi>>=shift;
qexp+=shift-7*m;
pi=((pi*pi)>>16);
qi=((qi*qi)>>16);
qexp=qexp*2+m;
-
+
pi*=(1<<14)-wi;
qi*=(1<<14)+wi;
qi=(qi+pi)>>14;
-
+
}
-
+
/* we've let the normalization drift because it wasn't important;
however, for the lookup, things must be normalized again. We
need at most one right shift or a number of left shifts */
if(qi&0xffff0000){ /* checks for 1.xxxxxxxxxxxxxxxx */
- qi>>=1; qexp++;
+ qi>>=1; qexp++;
}else
while(qi && !(qi&0x8000)){ /* checks for 0.0xxxxxxxxxxxxxxx or less*/
- qi<<=1; qexp--;
+ qi<<=1; qexp--;
}
amp=vorbis_fromdBlook_i(ampi* /* n.4 */
- vorbis_invsqlook_i(qi,qexp)-
- /* m.8, m+n<=8 */
- ampoffseti); /* 8.12[0] */
+ vorbis_invsqlook_i(qi,qexp)-
+ /* m.8, m+n<=8 */
+ ampoffseti); /* 8.12[0] */
curve[i]*=amp;
while(map[++i]==k)curve[i]*=amp;
}
}
-#else
+#else
/* old, nonoptimized but simple version for any poor sap who needs to
figure out what the hell this code does, or wants the other
/* side effect: changes *lsp to cosines of lsp */
void vorbis_lsp_to_curve(float *curve,int *map,int n,int ln,float *lsp,int m,
- float amp,float ampoffset){
+ float amp,float ampoffset){
int i;
float wdel=M_PI/ln;
for(i=0;i<m;i++)lsp[i]=2.f*cos(lsp[i]);
for(i=2; i<= ord; i++) {
for(j=ord; j >= i; j--) {
g[j-2] -= g[j];
- g[j] += g[j];
+ g[j] += g[j];
}
}
}
#define EPSILON 10e-7
static int Laguerre_With_Deflation(float *a,int ord,float *r){
int i,m;
- double lastdelta=0.f;
double *defl=alloca(sizeof(*defl)*(ord+1));
for(i=0;i<=ord;i++)defl[i]=a[i];
/* iterate a root */
while(1){
double p=defl[m],pp=0.f,ppp=0.f,denom;
-
+
/* eval the polynomial and its first two derivatives */
for(i=m;i>0;i--){
- ppp = new*ppp + pp;
- pp = new*pp + p;
- p = new*p + defl[i-1];
+ ppp = new*ppp + pp;
+ pp = new*pp + p;
+ p = new*p + defl[i-1];
}
-
+
/* Laguerre's method */
denom=(m-1) * ((m-1)*pp*pp - m*p*ppp);
if(denom<0)
- return(-1); /* complex root! The LPC generator handed us a bad filter */
+ return(-1); /* complex root! The LPC generator handed us a bad filter */
if(pp>0){
- denom = pp + sqrt(denom);
- if(denom<EPSILON)denom=EPSILON;
+ denom = pp + sqrt(denom);
+ if(denom<EPSILON)denom=EPSILON;
}else{
- denom = pp - sqrt(denom);
- if(denom>-(EPSILON))denom=-(EPSILON);
+ denom = pp - sqrt(denom);
+ if(denom>-(EPSILON))denom=-(EPSILON);
}
delta = m*p/denom;
if(delta<0.f)delta*=-1;
- if(fabs(delta/new)<10e-12)break;
- lastdelta=delta;
+ if(fabs(delta/new)<10e-12)break;
}
r[m-1]=new;
/* forward deflation */
-
+
for(i=m;i>0;i--)
defl[i-1]+=new*defl[i];
defl++;
double *root=alloca(ord*sizeof(*root));
for(i=0; i<ord;i++) root[i] = r[i];
-
+
while(error>1e-20){
error=0;
-
+
for(i=0; i<ord; i++) { /* Update each point. */
double pp=0.,delta;
double rooti=root[i];
double p=a[ord];
for(k=ord-1; k>= 0; k--) {
- pp= pp* rooti + p;
- p = p * rooti + a[k];
+ pp= pp* rooti + p;
+ p = p * rooti + a[k];
}
delta = p/pp;
root[i] -= delta;
error+= delta*delta;
}
-
+
if(count>40)return(-1);
-
+
count++;
}
/* Compute the first half of K & R F1 & F2 polynomials. */
/* Compute half of the symmetric and antisymmetric polynomials. */
/* Remove the roots at +1 and -1. */
-
+
g1[g1_order] = 1.f;
for(i=1;i<=g1_order;i++) g1[g1_order-i] = lpc[i-1]+lpc[m-i];
g2[g2_order] = 1.f;
for(i=1;i<=g2_order;i++) g2[g2_order-i] = lpc[i-1]-lpc[m-i];
-
+
if(g1_order>g2_order){
for(i=2; i<=g2_order;i++) g2[g2_order-i] += g2[g2_order-i+2];
}else{
projects / platform / upstream / libvorbis.git / blobdiff