source: downloads/libvorbis-1.2.0/lib/floor1.c @ 58

/********************************************************************
 *                                                                  *
 * THIS FILE IS PART OF THE OggVorbis SOFTWARE CODEC SOURCE CODE.   *
 * USE, DISTRIBUTION AND REPRODUCTION OF THIS LIBRARY SOURCE IS     *
 * 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/                  *
 *                                                                  *
 ********************************************************************

 function: floor backend 1 implementation
 last mod: $Id: floor1.c 13293 2007-07-24 00:09:47Z xiphmont $

 ********************************************************************/

#include <stdlib.h>
#include <string.h>
#include <math.h>
#include <ogg/ogg.h>
#include "vorbis/codec.h"
#include "codec_internal.h"
#include "registry.h"
#include "codebook.h"
#include "misc.h"
#include "scales.h"

#include <stdio.h>

#define floor1_rangedB 140 /* floor 1 fixed at -140dB to 0dB range */

typedef struct {
  int sorted_index[VIF_POSIT+2];
  int forward_index[VIF_POSIT+2];
  int reverse_index[VIF_POSIT+2];
  
  int hineighbor[VIF_POSIT];
  int loneighbor[VIF_POSIT];
  int posts;

  int n;
  int quant_q;
  vorbis_info_floor1 *vi;

  long phrasebits;
  long postbits;
  long frames;
} vorbis_look_floor1;

typedef struct lsfit_acc{
  long x0;
  long x1;

  long xa;
  long ya;
  long x2a;
  long y2a;
  long xya; 
  long an;
} lsfit_acc;

/***********************************************/
 
static void floor1_free_info(vorbis_info_floor *i){
  vorbis_info_floor1 *info=(vorbis_info_floor1 *)i;
  if(info){
    memset(info,0,sizeof(*info));
    _ogg_free(info);
  }
}

static void floor1_free_look(vorbis_look_floor *i){
  vorbis_look_floor1 *look=(vorbis_look_floor1 *)i;
  if(look){
    /*fprintf(stderr,"floor 1 bit usage %f:%f (%f total)\n",
            (float)look->phrasebits/look->frames,
            (float)look->postbits/look->frames,
            (float)(look->postbits+look->phrasebits)/look->frames);*/

    memset(look,0,sizeof(*look));
    _ogg_free(look);
  }
}

static int ilog(unsigned int v){
  int ret=0;
  while(v){
    ret++;
    v>>=1;
  }
  return(ret);
}

static int ilog2(unsigned int v){
  int ret=0;
  if(v)--v;
  while(v){
    ret++;
    v>>=1;
  }
  return(ret);
}

static void floor1_pack (vorbis_info_floor *i,oggpack_buffer *opb){
  vorbis_info_floor1 *info=(vorbis_info_floor1 *)i;
  int j,k;
  int count=0;
  int rangebits;
  int maxposit=info->postlist[1];
  int maxclass=-1;

  /* save out partitions */
  oggpack_write(opb,info->partitions,5); /* only 0 to 31 legal */
  for(j=0;j<info->partitions;j++){
    oggpack_write(opb,info->partitionclass[j],4); /* only 0 to 15 legal */
    if(maxclass<info->partitionclass[j])maxclass=info->partitionclass[j];
  }

  /* save out partition classes */
  for(j=0;j<maxclass+1;j++){
    oggpack_write(opb,info->class_dim[j]-1,3); /* 1 to 8 */
    oggpack_write(opb,info->class_subs[j],2); /* 0 to 3 */
    if(info->class_subs[j])oggpack_write(opb,info->class_book[j],8);
    for(k=0;k<(1<<info->class_subs[j]);k++)
      oggpack_write(opb,info->class_subbook[j][k]+1,8);
  }

  /* save out the post list */
  oggpack_write(opb,info->mult-1,2);     /* only 1,2,3,4 legal now */ 
  oggpack_write(opb,ilog2(maxposit),4);
  rangebits=ilog2(maxposit);

  for(j=0,k=0;j<info->partitions;j++){
    count+=info->class_dim[info->partitionclass[j]]; 
    for(;k<count;k++)
      oggpack_write(opb,info->postlist[k+2],rangebits);
  }
}


static vorbis_info_floor *floor1_unpack (vorbis_info *vi,oggpack_buffer *opb){
  codec_setup_info     *ci=vi->codec_setup;
  int j,k,count=0,maxclass=-1,rangebits;

  vorbis_info_floor1 *info=_ogg_calloc(1,sizeof(*info));
  /* read partitions */
  info->partitions=oggpack_read(opb,5); /* only 0 to 31 legal */
  for(j=0;j<info->partitions;j++){
    info->partitionclass[j]=oggpack_read(opb,4); /* only 0 to 15 legal */
    if(maxclass<info->partitionclass[j])maxclass=info->partitionclass[j];
  }

  /* read partition classes */
  for(j=0;j<maxclass+1;j++){
    info->class_dim[j]=oggpack_read(opb,3)+1; /* 1 to 8 */
    info->class_subs[j]=oggpack_read(opb,2); /* 0,1,2,3 bits */
    if(info->class_subs[j]<0)
      goto err_out;
    if(info->class_subs[j])info->class_book[j]=oggpack_read(opb,8);
    if(info->class_book[j]<0 || info->class_book[j]>=ci->books)
      goto err_out;
    for(k=0;k<(1<<info->class_subs[j]);k++){
      info->class_subbook[j][k]=oggpack_read(opb,8)-1;
      if(info->class_subbook[j][k]<-1 || info->class_subbook[j][k]>=ci->books)
        goto err_out;
    }
  }

  /* read the post list */
  info->mult=oggpack_read(opb,2)+1;     /* only 1,2,3,4 legal now */ 
  rangebits=oggpack_read(opb,4);

  for(j=0,k=0;j<info->partitions;j++){
    count+=info->class_dim[info->partitionclass[j]]; 
    for(;k<count;k++){
      int t=info->postlist[k+2]=oggpack_read(opb,rangebits);
      if(t<0 || t>=(1<<rangebits))
        goto err_out;
    }
  }
  info->postlist[0]=0;
  info->postlist[1]=1<<rangebits;

  return(info);
  
 err_out:
  floor1_free_info(info);
  return(NULL);
}

static int icomp(const void *a,const void *b){
  return(**(int **)a-**(int **)b);
}

static vorbis_look_floor *floor1_look(vorbis_dsp_state *vd,
                                      vorbis_info_floor *in){

  int *sortpointer[VIF_POSIT+2];
  vorbis_info_floor1 *info=(vorbis_info_floor1 *)in;
  vorbis_look_floor1 *look=_ogg_calloc(1,sizeof(*look));
  int i,j,n=0;

  look->vi=info;
  look->n=info->postlist[1];
 
  /* we drop each position value in-between already decoded values,
     and use linear interpolation to predict each new value past the
     edges.  The positions are read in the order of the position
     list... we precompute the bounding positions in the lookup.  Of
     course, the neighbors can change (if a position is declined), but
     this is an initial mapping */

  for(i=0;i<info->partitions;i++)n+=info->class_dim[info->partitionclass[i]];
  n+=2;
  look->posts=n;

  /* also store a sorted position index */
  for(i=0;i<n;i++)sortpointer[i]=info->postlist+i;
  qsort(sortpointer,n,sizeof(*sortpointer),icomp);

  /* points from sort order back to range number */
  for(i=0;i<n;i++)look->forward_index[i]=sortpointer[i]-info->postlist;
  /* points from range order to sorted position */
  for(i=0;i<n;i++)look->reverse_index[look->forward_index[i]]=i;
  /* we actually need the post values too */
  for(i=0;i<n;i++)look->sorted_index[i]=info->postlist[look->forward_index[i]];
  
  /* quantize values to multiplier spec */
  switch(info->mult){
  case 1: /* 1024 -> 256 */
    look->quant_q=256;
    break;
  case 2: /* 1024 -> 128 */
    look->quant_q=128;
    break;
  case 3: /* 1024 -> 86 */
    look->quant_q=86;
    break;
  case 4: /* 1024 -> 64 */
    look->quant_q=64;
    break;
  }

  /* discover our neighbors for decode where we don't use fit flags
     (that would push the neighbors outward) */
  for(i=0;i<n-2;i++){
    int lo=0;
    int hi=1;
    int lx=0;
    int hx=look->n;
    int currentx=info->postlist[i+2];
    for(j=0;j<i+2;j++){
      int x=info->postlist[j];
      if(x>lx && x<currentx){
        lo=j;
        lx=x;
      }
      if(x<hx && x>currentx){
        hi=j;
        hx=x;
      }
    }
    look->loneighbor[i]=lo;
    look->hineighbor[i]=hi;
  }

  return(look);
}

static int render_point(int x0,int x1,int y0,int y1,int x){
  y0&=0x7fff; /* mask off flag */
  y1&=0x7fff;
    
  {
    int dy=y1-y0;
    int adx=x1-x0;
    int ady=abs(dy);
    int err=ady*(x-x0);
    
    int off=err/adx;
    if(dy<0)return(y0-off);
    return(y0+off);
  }
}

static int vorbis_dBquant(const float *x){
  int i= *x*7.3142857f+1023.5f;
  if(i>1023)return(1023);
  if(i<0)return(0);
  return i;
}

static float FLOOR1_fromdB_LOOKUP[256]={
  1.0649863e-07F, 1.1341951e-07F, 1.2079015e-07F, 1.2863978e-07F, 
  1.3699951e-07F, 1.4590251e-07F, 1.5538408e-07F, 1.6548181e-07F, 
  1.7623575e-07F, 1.8768855e-07F, 1.9988561e-07F, 2.128753e-07F, 
  2.2670913e-07F, 2.4144197e-07F, 2.5713223e-07F, 2.7384213e-07F, 
  2.9163793e-07F, 3.1059021e-07F, 3.3077411e-07F, 3.5226968e-07F, 
  3.7516214e-07F, 3.9954229e-07F, 4.2550680e-07F, 4.5315863e-07F, 
  4.8260743e-07F, 5.1396998e-07F, 5.4737065e-07F, 5.8294187e-07F, 
  6.2082472e-07F, 6.6116941e-07F, 7.0413592e-07F, 7.4989464e-07F, 
  7.9862701e-07F, 8.5052630e-07F, 9.0579828e-07F, 9.6466216e-07F, 
  1.0273513e-06F, 1.0941144e-06F, 1.1652161e-06F, 1.2409384e-06F, 
  1.3215816e-06F, 1.4074654e-06F, 1.4989305e-06F, 1.5963394e-06F, 
  1.7000785e-06F, 1.8105592e-06F, 1.9282195e-06F, 2.0535261e-06F, 
  2.1869758e-06F, 2.3290978e-06F, 2.4804557e-06F, 2.6416497e-06F, 
  2.8133190e-06F, 2.9961443e-06F, 3.1908506e-06F, 3.3982101e-06F, 
  3.6190449e-06F, 3.8542308e-06F, 4.1047004e-06F, 4.3714470e-06F, 
  4.6555282e-06F, 4.9580707e-06F, 5.2802740e-06F, 5.6234160e-06F, 
  5.9888572e-06F, 6.3780469e-06F, 6.7925283e-06F, 7.2339451e-06F, 
  7.7040476e-06F, 8.2047000e-06F, 8.7378876e-06F, 9.3057248e-06F, 
  9.9104632e-06F, 1.0554501e-05F, 1.1240392e-05F, 1.1970856e-05F, 
  1.2748789e-05F, 1.3577278e-05F, 1.4459606e-05F, 1.5399272e-05F, 
  1.6400004e-05F, 1.7465768e-05F, 1.8600792e-05F, 1.9809576e-05F, 
  2.1096914e-05F, 2.2467911e-05F, 2.3928002e-05F, 2.5482978e-05F, 
  2.7139006e-05F, 2.8902651e-05F, 3.0780908e-05F, 3.2781225e-05F, 
  3.4911534e-05F, 3.7180282e-05F, 3.9596466e-05F, 4.2169667e-05F, 
  4.4910090e-05F, 4.7828601e-05F, 5.0936773e-05F, 5.4246931e-05F, 
  5.7772202e-05F, 6.1526565e-05F, 6.5524908e-05F, 6.9783085e-05F, 
  7.4317983e-05F, 7.9147585e-05F, 8.4291040e-05F, 8.9768747e-05F, 
  9.5602426e-05F, 0.00010181521F, 0.00010843174F, 0.00011547824F, 
  0.00012298267F, 0.00013097477F, 0.00013948625F, 0.00014855085F, 
  0.00015820453F, 0.00016848555F, 0.00017943469F, 0.00019109536F, 
  0.00020351382F, 0.00021673929F, 0.00023082423F, 0.00024582449F, 
  0.00026179955F, 0.00027881276F, 0.00029693158F, 0.00031622787F, 
  0.00033677814F, 0.00035866388F, 0.00038197188F, 0.00040679456F, 
  0.00043323036F, 0.00046138411F, 0.00049136745F, 0.00052329927F, 
  0.00055730621F, 0.00059352311F, 0.00063209358F, 0.00067317058F, 
  0.00071691700F, 0.00076350630F, 0.00081312324F, 0.00086596457F, 
  0.00092223983F, 0.00098217216F, 0.0010459992F, 0.0011139742F, 
  0.0011863665F, 0.0012634633F, 0.0013455702F, 0.0014330129F, 
  0.0015261382F, 0.0016253153F, 0.0017309374F, 0.0018434235F, 
  0.0019632195F, 0.0020908006F, 0.0022266726F, 0.0023713743F, 
  0.0025254795F, 0.0026895994F, 0.0028643847F, 0.0030505286F, 
  0.0032487691F, 0.0034598925F, 0.0036847358F, 0.0039241906F, 
  0.0041792066F, 0.0044507950F, 0.0047400328F, 0.0050480668F, 
  0.0053761186F, 0.0057254891F, 0.0060975636F, 0.0064938176F, 
  0.0069158225F, 0.0073652516F, 0.0078438871F, 0.0083536271F, 
  0.0088964928F, 0.009474637F, 0.010090352F, 0.010746080F, 
  0.011444421F, 0.012188144F, 0.012980198F, 0.013823725F, 
  0.014722068F, 0.015678791F, 0.016697687F, 0.017782797F, 
  0.018938423F, 0.020169149F, 0.021479854F, 0.022875735F, 
  0.024362330F, 0.025945531F, 0.027631618F, 0.029427276F, 
  0.031339626F, 0.033376252F, 0.035545228F, 0.037855157F, 
  0.040315199F, 0.042935108F, 0.045725273F, 0.048696758F, 
  0.051861348F, 0.055231591F, 0.058820850F, 0.062643361F, 
  0.066714279F, 0.071049749F, 0.075666962F, 0.080584227F, 
  0.085821044F, 0.091398179F, 0.097337747F, 0.10366330F, 
  0.11039993F, 0.11757434F, 0.12521498F, 0.13335215F, 
  0.14201813F, 0.15124727F, 0.16107617F, 0.17154380F, 
  0.18269168F, 0.19456402F, 0.20720788F, 0.22067342F, 
  0.23501402F, 0.25028656F, 0.26655159F, 0.28387361F, 
  0.30232132F, 0.32196786F, 0.34289114F, 0.36517414F, 
  0.38890521F, 0.41417847F, 0.44109412F, 0.46975890F, 
  0.50028648F, 0.53279791F, 0.56742212F, 0.60429640F, 
  0.64356699F, 0.68538959F, 0.72993007F, 0.77736504F, 
  0.82788260F, 0.88168307F, 0.9389798F, 1.F, 
};

static void render_line(int n, int x0,int x1,int y0,int y1,float *d){
  int dy=y1-y0;
  int adx=x1-x0;
  int ady=abs(dy);
  int base=dy/adx;
  int sy=(dy<0?base-1:base+1);
  int x=x0;
  int y=y0;
  int err=0;

  ady-=abs(base*adx);

  if(n>x1)n=x1;

  if(x<n)
    d[x]*=FLOOR1_fromdB_LOOKUP[y];

  while(++x<n){
    err=err+ady;
    if(err>=adx){
      err-=adx;
      y+=sy;
    }else{
      y+=base;
    }
    d[x]*=FLOOR1_fromdB_LOOKUP[y];
  }
}

static void render_line0(int x0,int x1,int y0,int y1,int *d){
  int dy=y1-y0;
  int adx=x1-x0;
  int ady=abs(dy);
  int base=dy/adx;
  int sy=(dy<0?base-1:base+1);
  int x=x0;
  int y=y0;
  int err=0;

  ady-=abs(base*adx);

  d[x]=y;
  while(++x<x1){
    err=err+ady;
    if(err>=adx){
      err-=adx;
      y+=sy;
    }else{
      y+=base;
    }
    d[x]=y;
  }
}

/* the floor has already been filtered to only include relevant sections */
static int accumulate_fit(const float *flr,const float *mdct,
                          int x0, int x1,lsfit_acc *a,
                          int n,vorbis_info_floor1 *info){
  long i;
  int quantized=vorbis_dBquant(flr+x0);

  long xa=0,ya=0,x2a=0,y2a=0,xya=0,na=0, xb=0,yb=0,x2b=0,y2b=0,xyb=0,nb=0;

  memset(a,0,sizeof(*a));
  a->x0=x0;
  a->x1=x1;
  if(x1>=n)x1=n-1;

  for(i=x0;i<=x1;i++){
    int quantized=vorbis_dBquant(flr+i);
    if(quantized){
      if(mdct[i]+info->twofitatten>=flr[i]){
        xa  += i;
        ya  += quantized;
        x2a += i*i;
        y2a += quantized*quantized;
        xya += i*quantized;
        na++;
      }else{
        xb  += i;
        yb  += quantized;
        x2b += i*i;
        y2b += quantized*quantized;
        xyb += i*quantized;
        nb++;
      }
    }
  }

  xb+=xa;
  yb+=ya;
  x2b+=x2a;
  y2b+=y2a;
  xyb+=xya;
  nb+=na;

  /* weight toward the actually used frequencies if we meet the threshhold */
  {
    int weight=nb*info->twofitweight/(na+1);

    a->xa=xa*weight+xb;
    a->ya=ya*weight+yb;
    a->x2a=x2a*weight+x2b;
    a->y2a=y2a*weight+y2b;
    a->xya=xya*weight+xyb;
    a->an=na*weight+nb;
  }

  return(na);
}

static void fit_line(lsfit_acc *a,int fits,int *y0,int *y1){
  long x=0,y=0,x2=0,y2=0,xy=0,an=0,i;
  long x0=a[0].x0;
  long x1=a[fits-1].x1;

  for(i=0;i<fits;i++){
    x+=a[i].xa;
    y+=a[i].ya;
    x2+=a[i].x2a;
    y2+=a[i].y2a;
    xy+=a[i].xya;
    an+=a[i].an;
  }

  if(*y0>=0){
    x+=   x0;
    y+=  *y0;
    x2+=  x0 *  x0;
    y2+= *y0 * *y0;
    xy+= *y0 *  x0;
    an++;
  }

  if(*y1>=0){
    x+=   x1;
    y+=  *y1;
    x2+=  x1 *  x1;
    y2+= *y1 * *y1;
    xy+= *y1 *  x1;
    an++;
  }
  
  if(an){
    /* need 64 bit multiplies, which C doesn't give portably as int */
    double fx=x;
    double fy=y;
    double fx2=x2;
    double fxy=xy;
    double denom=1./(an*fx2-fx*fx);
    double a=(fy*fx2-fxy*fx)*denom;
    double b=(an*fxy-fx*fy)*denom;
    *y0=rint(a+b*x0);
    *y1=rint(a+b*x1);
    
    /* limit to our range! */
    if(*y0>1023)*y0=1023;
    if(*y1>1023)*y1=1023;
    if(*y0<0)*y0=0;
    if(*y1<0)*y1=0;
    
  }else{
    *y0=0;
    *y1=0;
  }
}

/*static void fit_line_point(lsfit_acc *a,int fits,int *y0,int *y1){
  long y=0;
  int i;

  for(i=0;i<fits && y==0;i++)
    y+=a[i].ya;
  
  *y0=*y1=y;
  }*/

static int inspect_error(int x0,int x1,int y0,int y1,const float *mask,
                         const float *mdct,
                         vorbis_info_floor1 *info){
  int dy=y1-y0;
  int adx=x1-x0;
  int ady=abs(dy);
  int base=dy/adx;
  int sy=(dy<0?base-1:base+1);
  int x=x0;
  int y=y0;
  int err=0;
  int val=vorbis_dBquant(mask+x);
  int mse=0;
  int n=0;

  ady-=abs(base*adx);
  
  mse=(y-val);
  mse*=mse;
  n++;
  if(mdct[x]+info->twofitatten>=mask[x]){
    if(y+info->maxover<val)return(1);
    if(y-info->maxunder>val)return(1);
  }

  while(++x<x1){
    err=err+ady;
    if(err>=adx){
      err-=adx;
      y+=sy;
    }else{
      y+=base;
    }

    val=vorbis_dBquant(mask+x);
    mse+=((y-val)*(y-val));
    n++;
    if(mdct[x]+info->twofitatten>=mask[x]){
      if(val){
        if(y+info->maxover<val)return(1);
        if(y-info->maxunder>val)return(1);
      }
    }
  }
  
  if(info->maxover*info->maxover/n>info->maxerr)return(0);
  if(info->maxunder*info->maxunder/n>info->maxerr)return(0);
  if(mse/n>info->maxerr)return(1);
  return(0);
}

static int post_Y(int *A,int *B,int pos){
  if(A[pos]<0)
    return B[pos];
  if(B[pos]<0)
    return A[pos];

  return (A[pos]+B[pos])>>1;
}

static int seq=0;

int *floor1_fit(vorbis_block *vb,vorbis_look_floor1 *look,
                          const float *logmdct,   /* in */
                          const float *logmask){
  long i,j;
  vorbis_info_floor1 *info=look->vi;
  long n=look->n;
  long posts=look->posts;
  long nonzero=0;
  lsfit_acc fits[VIF_POSIT+1];
  int fit_valueA[VIF_POSIT+2]; /* index by range list position */
  int fit_valueB[VIF_POSIT+2]; /* index by range list position */

  int loneighbor[VIF_POSIT+2]; /* sorted index of range list position (+2) */
  int hineighbor[VIF_POSIT+2]; 
  int *output=NULL;
  int memo[VIF_POSIT+2];

  for(i=0;i<posts;i++)fit_valueA[i]=-200; /* mark all unused */
  for(i=0;i<posts;i++)fit_valueB[i]=-200; /* mark all unused */
  for(i=0;i<posts;i++)loneighbor[i]=0; /* 0 for the implicit 0 post */
  for(i=0;i<posts;i++)hineighbor[i]=1; /* 1 for the implicit post at n */
  for(i=0;i<posts;i++)memo[i]=-1;      /* no neighbor yet */

  /* quantize the relevant floor points and collect them into line fit
     structures (one per minimal division) at the same time */
  if(posts==0){
    nonzero+=accumulate_fit(logmask,logmdct,0,n,fits,n,info);
  }else{
    for(i=0;i<posts-1;i++)
      nonzero+=accumulate_fit(logmask,logmdct,look->sorted_index[i],
                              look->sorted_index[i+1],fits+i,
                              n,info);
  }
  
  if(nonzero){
    /* start by fitting the implicit base case.... */
    int y0=-200;
    int y1=-200;
    fit_line(fits,posts-1,&y0,&y1);

    fit_valueA[0]=y0;
    fit_valueB[0]=y0;
    fit_valueB[1]=y1;
    fit_valueA[1]=y1;

    /* Non degenerate case */
    /* start progressive splitting.  This is a greedy, non-optimal
       algorithm, but simple and close enough to the best
       answer. */
    for(i=2;i<posts;i++){
      int sortpos=look->reverse_index[i];
      int ln=loneighbor[sortpos];
      int hn=hineighbor[sortpos];
      
      /* eliminate repeat searches of a particular range with a memo */
      if(memo[ln]!=hn){
        /* haven't performed this error search yet */
        int lsortpos=look->reverse_index[ln];
        int hsortpos=look->reverse_index[hn];
        memo[ln]=hn;
                
        {
          /* A note: we want to bound/minimize *local*, not global, error */
          int lx=info->postlist[ln];
          int hx=info->postlist[hn];      
          int ly=post_Y(fit_valueA,fit_valueB,ln);
          int hy=post_Y(fit_valueA,fit_valueB,hn);
          
          if(ly==-1 || hy==-1){
            exit(1);
          }

          if(inspect_error(lx,hx,ly,hy,logmask,logmdct,info)){
            /* outside error bounds/begin search area.  Split it. */
            int ly0=-200;
            int ly1=-200;
            int hy0=-200;
            int hy1=-200;
            fit_line(fits+lsortpos,sortpos-lsortpos,&ly0,&ly1);
            fit_line(fits+sortpos,hsortpos-sortpos,&hy0,&hy1);
            
            /* store new edge values */
            fit_valueB[ln]=ly0;
            if(ln==0)fit_valueA[ln]=ly0;
            fit_valueA[i]=ly1;
            fit_valueB[i]=hy0;
            fit_valueA[hn]=hy1;
            if(hn==1)fit_valueB[hn]=hy1;
            
            if(ly1>=0 || hy0>=0){
              /* store new neighbor values */
              for(j=sortpos-1;j>=0;j--)
                if(hineighbor[j]==hn)
                  hineighbor[j]=i;
                else
                  break;
              for(j=sortpos+1;j<posts;j++)
                if(loneighbor[j]==ln)
                  loneighbor[j]=i;
                else
                  break;
              
            }
          }else{
            
            fit_valueA[i]=-200;
            fit_valueB[i]=-200;
          }
        }
      }
    }
  
    output=_vorbis_block_alloc(vb,sizeof(*output)*posts);
    
    output[0]=post_Y(fit_valueA,fit_valueB,0);
    output[1]=post_Y(fit_valueA,fit_valueB,1);
    
    /* fill in posts marked as not using a fit; we will zero
       back out to 'unused' when encoding them so long as curve
       interpolation doesn't force them into use */
    for(i=2;i<posts;i++){
      int ln=look->loneighbor[i-2];
      int hn=look->hineighbor[i-2];
      int x0=info->postlist[ln];
      int x1=info->postlist[hn];
      int y0=output[ln];
      int y1=output[hn];
      
      int predicted=render_point(x0,x1,y0,y1,info->postlist[i]);
      int vx=post_Y(fit_valueA,fit_valueB,i);
      
      if(vx>=0 && predicted!=vx){ 
        output[i]=vx;
      }else{
        output[i]= predicted|0x8000;
      }
    }
  }

  return(output);
  
}
                
int *floor1_interpolate_fit(vorbis_block *vb,vorbis_look_floor1 *look,
                          int *A,int *B,
                          int del){

  long i;
  long posts=look->posts;
  int *output=NULL;
  
  if(A && B){
    output=_vorbis_block_alloc(vb,sizeof(*output)*posts);
    
    for(i=0;i<posts;i++){
      output[i]=((65536-del)*(A[i]&0x7fff)+del*(B[i]&0x7fff)+32768)>>16;
      if(A[i]&0x8000 && B[i]&0x8000)output[i]|=0x8000;
    }
  }

  return(output);
}


int floor1_encode(oggpack_buffer *opb,vorbis_block *vb,
                  vorbis_look_floor1 *look,
                  int *post,int *ilogmask){

  long i,j;
  vorbis_info_floor1 *info=look->vi;
  long n=look->n;
  long posts=look->posts;
  codec_setup_info *ci=vb->vd->vi->codec_setup;
  int out[VIF_POSIT+2];
  static_codebook **sbooks=ci->book_param;
  codebook *books=ci->fullbooks;
  static long seq=0; 

  /* quantize values to multiplier spec */
  if(post){
    for(i=0;i<posts;i++){
      int val=post[i]&0x7fff;
      switch(info->mult){
      case 1: /* 1024 -> 256 */
        val>>=2;
        break;
      case 2: /* 1024 -> 128 */
        val>>=3;
        break;
      case 3: /* 1024 -> 86 */
        val/=12;
        break;
      case 4: /* 1024 -> 64 */
        val>>=4;
        break;
      }
      post[i]=val | (post[i]&0x8000);
    }

    out[0]=post[0];
    out[1]=post[1];

    /* find prediction values for each post and subtract them */
    for(i=2;i<posts;i++){
      int ln=look->loneighbor[i-2];
      int hn=look->hineighbor[i-2];
      int x0=info->postlist[ln];
      int x1=info->postlist[hn];
      int y0=post[ln];
      int y1=post[hn];
      
      int predicted=render_point(x0,x1,y0,y1,info->postlist[i]);
      
      if((post[i]&0x8000) || (predicted==post[i])){
        post[i]=predicted|0x8000; /* in case there was roundoff jitter
                                     in interpolation */
        out[i]=0;
      }else{
        int headroom=(look->quant_q-predicted<predicted?
                      look->quant_q-predicted:predicted);
        
        int val=post[i]-predicted;
        
        /* at this point the 'deviation' value is in the range +/- max
           range, but the real, unique range can always be mapped to
           only [0-maxrange).  So we want to wrap the deviation into
           this limited range, but do it in the way that least screws
           an essentially gaussian probability distribution. */
        
        if(val<0)
          if(val<-headroom)
            val=headroom-val-1;
          else
            val=-1-(val<<1);
        else
          if(val>=headroom)
            val= val+headroom;
          else
            val<<=1;
        
        out[i]=val;
        post[ln]&=0x7fff;
        post[hn]&=0x7fff;
      }
    }
    
    /* we have everything we need. pack it out */
    /* mark nontrivial floor */
    oggpack_write(opb,1,1);
      
    /* beginning/end post */
    look->frames++;
    look->postbits+=ilog(look->quant_q-1)*2;
    oggpack_write(opb,out[0],ilog(look->quant_q-1));
    oggpack_write(opb,out[1],ilog(look->quant_q-1));
      
      
    /* partition by partition */
    for(i=0,j=2;i<info->partitions;i++){
      int class=info->partitionclass[i];
      int cdim=info->class_dim[class];
      int csubbits=info->class_subs[class];
      int csub=1<<csubbits;
      int bookas[8]={0,0,0,0,0,0,0,0};
      int cval=0;
      int cshift=0;
      int k,l;

      /* generate the partition's first stage cascade value */
      if(csubbits){
        int maxval[8];
        for(k=0;k<csub;k++){
          int booknum=info->class_subbook[class][k];
          if(booknum<0){
            maxval[k]=1;
          }else{
            maxval[k]=sbooks[info->class_subbook[class][k]]->entries;
          }
        }
        for(k=0;k<cdim;k++){
          for(l=0;l<csub;l++){
            int val=out[j+k];
            if(val<maxval[l]){
              bookas[k]=l;
              break;
            }
          }
          cval|= bookas[k]<<cshift;
          cshift+=csubbits;
        }
        /* write it */
        look->phrasebits+=
          vorbis_book_encode(books+info->class_book[class],cval,opb);
        
#ifdef TRAIN_FLOOR1
        {
          FILE *of;
          char buffer[80];
          sprintf(buffer,"line_%dx%ld_class%d.vqd",
                  vb->pcmend/2,posts-2,class);
          of=fopen(buffer,"a");
          fprintf(of,"%d\n",cval);
          fclose(of);
        }
#endif
      }
        
      /* write post values */
      for(k=0;k<cdim;k++){
        int book=info->class_subbook[class][bookas[k]];
        if(book>=0){
          /* hack to allow training with 'bad' books */
          if(out[j+k]<(books+book)->entries)
            look->postbits+=vorbis_book_encode(books+book,
                                               out[j+k],opb);
          /*else
            fprintf(stderr,"+!");*/
          
#ifdef TRAIN_FLOOR1
          {
            FILE *of;
            char buffer[80];
            sprintf(buffer,"line_%dx%ld_%dsub%d.vqd",
                    vb->pcmend/2,posts-2,class,bookas[k]);
            of=fopen(buffer,"a");
            fprintf(of,"%d\n",out[j+k]);
            fclose(of);
          }
#endif
        }
      }
      j+=cdim;
    }
    
    {
      /* generate quantized floor equivalent to what we'd unpack in decode */
      /* render the lines */
      int hx=0;
      int lx=0;
      int ly=post[0]*info->mult;
      for(j=1;j<look->posts;j++){
        int current=look->forward_index[j];
        int hy=post[current]&0x7fff;
        if(hy==post[current]){
          
          hy*=info->mult;
          hx=info->postlist[current];
        
          render_line0(lx,hx,ly,hy,ilogmask);
        
          lx=hx;
          ly=hy;
        }
      }
      for(j=hx;j<vb->pcmend/2;j++)ilogmask[j]=ly; /* be certain */    
      seq++;
      return(1);
    }
  }else{
    oggpack_write(opb,0,1);
    memset(ilogmask,0,vb->pcmend/2*sizeof(*ilogmask));
    seq++;
    return(0);
  }
}

static void *floor1_inverse1(vorbis_block *vb,vorbis_look_floor *in){
  vorbis_look_floor1 *look=(vorbis_look_floor1 *)in;
  vorbis_info_floor1 *info=look->vi;
  codec_setup_info   *ci=vb->vd->vi->codec_setup;
  
  int i,j,k;
  codebook *books=ci->fullbooks;   

  /* unpack wrapped/predicted values from stream */
  if(oggpack_read(&vb->opb,1)==1){
    int *fit_value=_vorbis_block_alloc(vb,(look->posts)*sizeof(*fit_value));

    fit_value[0]=oggpack_read(&vb->opb,ilog(look->quant_q-1));
    fit_value[1]=oggpack_read(&vb->opb,ilog(look->quant_q-1));

    /* partition by partition */
    for(i=0,j=2;i<info->partitions;i++){
      int class=info->partitionclass[i];
      int cdim=info->class_dim[class];
      int csubbits=info->class_subs[class];
      int csub=1<<csubbits;
      int cval=0;

      /* decode the partition's first stage cascade value */
      if(csubbits){
        cval=vorbis_book_decode(books+info->class_book[class],&vb->opb);

        if(cval==-1)goto eop;
      }

      for(k=0;k<cdim;k++){
        int book=info->class_subbook[class][cval&(csub-1)];
        cval>>=csubbits;
        if(book>=0){
          if((fit_value[j+k]=vorbis_book_decode(books+book,&vb->opb))==-1)
            goto eop;
        }else{
          fit_value[j+k]=0;
        }
      }
      j+=cdim;
    }

    /* unwrap positive values and reconsitute via linear interpolation */
    for(i=2;i<look->posts;i++){
      int predicted=render_point(info->postlist[look->loneighbor[i-2]],
                                 info->postlist[look->hineighbor[i-2]],
                                 fit_value[look->loneighbor[i-2]],
                                 fit_value[look->hineighbor[i-2]],
                                 info->postlist[i]);
      int hiroom=look->quant_q-predicted;
      int loroom=predicted;
      int room=(hiroom<loroom?hiroom:loroom)<<1;
      int val=fit_value[i];

      if(val){
        if(val>=room){
          if(hiroom>loroom){
            val = val-loroom;
          }else{
            val = -1-(val-hiroom);
          }
        }else{
          if(val&1){
            val= -((val+1)>>1);
          }else{
            val>>=1;
          }
        }

        fit_value[i]=val+predicted;
        fit_value[look->loneighbor[i-2]]&=0x7fff;
        fit_value[look->hineighbor[i-2]]&=0x7fff;

      }else{
        fit_value[i]=predicted|0x8000;
      }
        
    }

    return(fit_value);
  }
 eop:
  return(NULL);
}

static int floor1_inverse2(vorbis_block *vb,vorbis_look_floor *in,void *memo,
                          float *out){
  vorbis_look_floor1 *look=(vorbis_look_floor1 *)in;
  vorbis_info_floor1 *info=look->vi;

  codec_setup_info   *ci=vb->vd->vi->codec_setup;
  int                  n=ci->blocksizes[vb->W]/2;
  int j;

  if(memo){
    /* render the lines */
    int *fit_value=(int *)memo;
    int hx=0;
    int lx=0;
    int ly=fit_value[0]*info->mult;
    for(j=1;j<look->posts;j++){
      int current=look->forward_index[j];
      int hy=fit_value[current]&0x7fff;
      if(hy==fit_value[current]){
        
        hy*=info->mult;
        hx=info->postlist[current];
        
        render_line(n,lx,hx,ly,hy,out);
        
        lx=hx;
        ly=hy;
      }
    }
    for(j=hx;j<n;j++)out[j]*=FLOOR1_fromdB_LOOKUP[ly]; /* be certain */    
    return(1);
  }
  memset(out,0,sizeof(*out)*n);
  return(0);
}

/* export hooks */
vorbis_func_floor floor1_exportbundle={
  &floor1_pack,&floor1_unpack,&floor1_look,&floor1_free_info,
  &floor1_free_look,&floor1_inverse1,&floor1_inverse2
};