Two bugfixes (float) not (float *) and an optimization to
[platform/upstream/libvorbis.git] / lib / psy.c
index a511413..35df7e7 100644 (file)
--- a/lib/psy.c
+++ b/lib/psy.c
 /********************************************************************
  *                                                                  *
- * THIS FILE IS PART OF THE Ogg Vorbis SOFTWARE CODEC SOURCE CODE.  *
+ * THIS FILE IS PART OF THE OggVorbis SOFTWARE CODEC SOURCE CODE.   *
  * USE, DISTRIBUTION AND REPRODUCTION OF THIS SOURCE IS GOVERNED BY *
- * THE GNU PUBLIC LICENSE 2, WHICH IS INCLUDED WITH THIS SOURCE.    *
- * PLEASE READ THESE TERMS DISTRIBUTING.                            *
+ * THE GNU LESSER/LIBRARY PUBLIC LICENSE, WHICH IS INCLUDED WITH    *
+ * THIS SOURCE. PLEASE READ THESE TERMS BEFORE DISTRIBUTING.        *
  *                                                                  *
- * THE OggSQUISH SOURCE CODE IS (C) COPYRIGHT 1994-1999             *
- * by 1999 Monty <monty@xiph.org> and The XIPHOPHORUS Company       *
+ * THE OggVorbis SOURCE CODE IS (C) COPYRIGHT 1994-2000             *
+ * by Monty <monty@xiph.org> and the XIPHOPHORUS Company            *
  * http://www.xiph.org/                                             *
  *                                                                  *
  ********************************************************************
 
- function: random psychoacoustics (not including preecho)
- author: Monty <xiphmont@mit.edu>
- modifications by: Monty
- last modification date: Aug 26 1999
+ function: psychoacoustics not including preecho
+ last mod: $Id: psy.c,v 1.40 2001/02/02 02:52:34 xiphmont Exp $
 
  ********************************************************************/
 
+#include <stdlib.h>
 #include <math.h>
 #include <string.h>
-#include "stdio.h"
-#include "codec.h"
+#include "vorbis/codec.h"
+#include "codec_internal.h"
+
+#include "masking.h"
 #include "psy.h"
+#include "os.h"
 #include "lpc.h"
 #include "smallft.h"
-#include "xlogmap.h"
+#include "scales.h"
+#include "misc.h"
+
+#define NEGINF -9999.f
 
-#define NOISEdB -6
+/* Why Bark scale for encoding but not masking computation? Because
+   masking has a strong harmonic dependancy */
+
+/* the beginnings of real psychoacoustic infrastructure.  This is
+   still not tightly tuned */
+void _vi_psy_free(vorbis_info_psy *i){
+  if(i){
+    memset(i,0,sizeof(vorbis_info_psy));
+    _ogg_free(i);
+  }
+}
 
-#define MASKdB  20
-#define HROLL   60
-#define LROLL   90
-#define MASKBIAS  10
+vorbis_info_psy *_vi_psy_copy(vorbis_info_psy *i){
+  vorbis_info_psy *ret=_ogg_malloc(sizeof(vorbis_info_psy));
+  memcpy(ret,i,sizeof(vorbis_info_psy));
+  return(ret);
+}
 
-#define LNOISE  .95
-#define HNOISE  1.01
-#define NOISEBIAS  20
+/* Set up decibel threshold slopes on a Bark frequency scale */
+/* ATH is the only bit left on a Bark scale.  No reason to change it
+   right now */
+static void set_curve(float *ref,float *c,int n, float crate){
+  int i,j=0;
+
+  for(i=0;i<MAX_BARK-1;i++){
+    int endpos=rint(fromBARK(i+1)*2*n/crate);
+    float base=ref[i];
+    if(j<endpos){
+      float delta=(ref[i+1]-base)/(endpos-j);
+      for(;j<endpos && j<n;j++){
+       c[j]=base;
+       base+=delta;
+      }
+    }
+  }
+}
 
-/* Find the mean log energy of a given 'band'; used to evaluate tones
-   against background noise */
+static void min_curve(float *c,
+                      float *c2){
+  int i;  
+  for(i=0;i<EHMER_MAX;i++)if(c2[i]<c[i])c[i]=c2[i];
+}
+static void max_curve(float *c,
+                      float *c2){
+  int i;  
+  for(i=0;i<EHMER_MAX;i++)if(c2[i]>c[i])c[i]=c2[i];
+}
 
-/* This is faster than a real convolution, gives us roughly the log f
-   scale we seek, and gives OK results.  So, that means it's a good
-   hack */
+static void attenuate_curve(float *c,float att){
+  int i;
+  for(i=0;i<EHMER_MAX;i++)
+    c[i]+=att;
+}
 
-/* To add: f scale noise attenuation curve */
+static void interp_curve(float *c,float *c1,float *c2,float del){
+  int i;
+  for(i=0;i<EHMER_MAX;i++)
+    c[i]=c2[i]*del+c1[i]*(1.f-del);
+}
 
-void _vp_noise_floor(double *f, double *m,int n){
-  long lo=0,hi=0;
-  double acc=0,div=0;
+static void setup_curve(float **c,
+                       int band,
+                       float *curveatt_dB){
   int i,j;
+  float ath[EHMER_MAX];
+  float tempc[P_LEVELS][EHMER_MAX];
+
+  memcpy(c[0]+2,c[4]+2,sizeof(float)*EHMER_MAX);
+  memcpy(c[2]+2,c[4]+2,sizeof(float)*EHMER_MAX);
+
+  /* we add back in the ATH to avoid low level curves falling off to
+     -infinity and unneccessarily cutting off high level curves in the
+     curve limiting (last step).  But again, remember... a half-band's
+     settings must be valid over the whole band, and it's better to
+     mask too little than too much, so be pessimal. */
+
+  for(i=0;i<EHMER_MAX;i++){
+    float oc_min=band*.5+(i-EHMER_OFFSET)*.125;
+    float oc_max=band*.5+(i-EHMER_OFFSET+1)*.125;
+    float bark=toBARK(fromOC(oc_min));
+    int ibark=floor(bark);
+    float del=bark-ibark;
+    float ath_min,ath_max;
+
+    if(ibark<26)
+      ath_min=ATH_Bark_dB[ibark]*(1.f-del)+ATH_Bark_dB[ibark+1]*del;
+    else
+      ath_min=ATH_Bark_dB[25];
 
-  for(i=100;i<n;i++){
-    long newlo=i*LNOISE-NOISEBIAS;
-    long newhi=i*HNOISE+NOISEBIAS;
-    double temp;
-    
-    if(newhi>n)newhi=n;
-    if(newlo<0)newlo=0;
+    bark=toBARK(fromOC(oc_max));
+    ibark=floor(bark);
+    del=bark-ibark;
 
-    for(j=hi;j<newhi;j++){
-      acc+=todB(f[j]);
-      div++;
-    }
-    for(j=lo;j<newlo;j++){
-      acc-=todB(f[j]);
-      div--;
-    }
+    if(ibark<26)
+      ath_max=ATH_Bark_dB[ibark]*(1.f-del)+ATH_Bark_dB[ibark+1]*del;
+    else
+      ath_max=ATH_Bark_dB[25];
+
+    ath[i]=min(ath_min,ath_max);
+  }
 
-    hi=newhi;
-    lo=newlo;
+  /* The c array is comes in as dB curves at 20 40 60 80 100 dB.
+     interpolate intermediate dB curves */
+  for(i=1;i<P_LEVELS;i+=2){
+    interp_curve(c[i]+2,c[i-1]+2,c[i+1]+2,.5);
+  }
+
+  /* normalize curves so the driving amplitude is 0dB */
+  /* make temp curves with the ATH overlayed */
+  for(i=0;i<P_LEVELS;i++){
+    attenuate_curve(c[i]+2,curveatt_dB[i]);
+    memcpy(tempc[i],ath,EHMER_MAX*sizeof(float));
+    attenuate_curve(tempc[i],-i*10.f);
+    max_curve(tempc[i],c[i]+2);
+  }
+
+  /* Now limit the louder curves.
+
+     the idea is this: We don't know what the playback attenuation
+     will be; 0dB SL moves every time the user twiddles the volume
+     knob. So that means we have to use a single 'most pessimal' curve
+     for all masking amplitudes, right?  Wrong.  The *loudest* sound
+     can be in (we assume) a range of ...+100dB] SL.  However, sounds
+     20dB down will be in a range ...+80], 40dB down is from ...+60],
+     etc... */
+
+  for(j=1;j<P_LEVELS;j++){
+    min_curve(tempc[j],tempc[j-1]);
+    min_curve(c[j]+2,tempc[j]);
+  }
+
+  /* add fenceposts */
+  for(j=0;j<P_LEVELS;j++){
+
+    for(i=0;i<EHMER_MAX;i++)
+      if(c[j][i+2]>-200.f)break;  
+    c[j][0]=i;
+
+    for(i=EHMER_MAX-1;i>=0;i--)
+      if(c[j][i+2]>-200.f)
+       break;
+    c[j][1]=i;
 
-    temp=fromdB(acc/div+NOISEdB); /* The NOISEdB constant should be an
-                                    attenuation curve */
-    if(m[i]<temp)m[i]=temp;
   }
 }
 
-/* figure the masking curve.  linear rolloff on a dB scale, adjusted
-   by octave */
-void _vp_mask_floor(double *f, double *m,int n){
-  double ocSCALE=1./log(2);
-  double curmask=-9.e40;
-  double curoc=log(MASKBIAS)*ocSCALE;
-  long i;
+void _vp_psy_init(vorbis_look_psy *p,vorbis_info_psy *vi,int n,long rate){
+  long i,j;
+  long maxoc;
+  memset(p,0,sizeof(vorbis_look_psy));
+
+
+  p->eighth_octave_lines=vi->eighth_octave_lines;
+  p->shiftoc=rint(log(vi->eighth_octave_lines*8)/log(2))-1;
+
+  p->firstoc=toOC(.25f*rate/n)*(1<<(p->shiftoc+1))-vi->eighth_octave_lines;
+  maxoc=toOC((n*.5f-.25f)*rate/n)*(1<<(p->shiftoc+1))+.5f;
+  p->total_octave_lines=maxoc-p->firstoc+1;
+
+  p->ath=_ogg_malloc(n*sizeof(float));
+  p->octave=_ogg_malloc(n*sizeof(int));
+  p->bark=_ogg_malloc(n*sizeof(float));
+  p->vi=vi;
+  p->n=n;
+
+  /* set up the lookups for a given blocksize and sample rate */
+  /* Vorbis max sample rate is currently limited by 26 Bark (54kHz) */
+  set_curve(ATH_Bark_dB, p->ath,n,rate);
+  for(i=0;i<n;i++)
+    p->bark[i]=toBARK(rate/(2*n)*i); 
+
+  for(i=0;i<n;i++)
+    p->octave[i]=toOC((i*.5f+.25f)*rate/n)*(1<<(p->shiftoc+1))+.5f;
+
+  p->tonecurves=_ogg_malloc(P_BANDS*sizeof(float **));
+  p->noisemedian=_ogg_malloc(n*sizeof(float));
+  p->noiseoffset=_ogg_malloc(n*sizeof(float));
+  p->peakatt=_ogg_malloc(P_BANDS*sizeof(float *));
+  for(i=0;i<P_BANDS;i++){
+    p->tonecurves[i]=_ogg_malloc(P_LEVELS*sizeof(float *));
+    p->peakatt[i]=_ogg_malloc(P_LEVELS*sizeof(float));
+  }
 
-  /* run mask forward then backward */
-  for(i=0;i<n;i++){
-    double newmask=todB(f[i])-MASKdB;
-    double newoc=log(i+MASKBIAS)*ocSCALE;
-    double roll=curmask-(newoc-curoc)*HROLL;
-    double lroll;
-    if(newmask>roll){
-      roll=curmask=newmask;
-      curoc=newoc;
+  for(i=0;i<P_BANDS;i++)
+    for(j=0;j<P_LEVELS;j++){
+      p->tonecurves[i][j]=_ogg_malloc((EHMER_MAX+2)*sizeof(float));
     }
-    lroll=fromdB(roll);
-    if(m[i]<lroll)m[i]=lroll;
-  }
-
-  curmask=-9.e40;
-  curoc=log(n+MASKBIAS)*ocSCALE;
-  for(i=n-1;i>=0;i--){
-    double newmask=todB(f[i])-MASKdB;
-    double newoc=log(i+MASKBIAS)*ocSCALE;
-    double roll=curmask-(curoc-newoc)*LROLL;
-    double lroll;
-    if(newmask>roll){
-      roll=curmask=newmask;
-      curoc=newoc;
+
+  /* OK, yeah, this was a silly way to do it */
+  memcpy(p->tonecurves[0][4]+2,tone_125_40dB_SL,sizeof(float)*EHMER_MAX);
+  memcpy(p->tonecurves[0][6]+2,tone_125_60dB_SL,sizeof(float)*EHMER_MAX);
+  memcpy(p->tonecurves[0][8]+2,tone_125_80dB_SL,sizeof(float)*EHMER_MAX);
+  memcpy(p->tonecurves[0][10]+2,tone_125_100dB_SL,sizeof(float)*EHMER_MAX);
+
+  memcpy(p->tonecurves[2][4]+2,tone_125_40dB_SL,sizeof(float)*EHMER_MAX);
+  memcpy(p->tonecurves[2][6]+2,tone_125_60dB_SL,sizeof(float)*EHMER_MAX);
+  memcpy(p->tonecurves[2][8]+2,tone_125_80dB_SL,sizeof(float)*EHMER_MAX);
+  memcpy(p->tonecurves[2][10]+2,tone_125_100dB_SL,sizeof(float)*EHMER_MAX);
+
+  memcpy(p->tonecurves[4][4]+2,tone_250_40dB_SL,sizeof(float)*EHMER_MAX);
+  memcpy(p->tonecurves[4][6]+2,tone_250_60dB_SL,sizeof(float)*EHMER_MAX);
+  memcpy(p->tonecurves[4][8]+2,tone_250_80dB_SL,sizeof(float)*EHMER_MAX);
+  memcpy(p->tonecurves[4][10]+2,tone_250_100dB_SL,sizeof(float)*EHMER_MAX);
+
+  memcpy(p->tonecurves[6][4]+2,tone_500_40dB_SL,sizeof(float)*EHMER_MAX);
+  memcpy(p->tonecurves[6][6]+2,tone_500_60dB_SL,sizeof(float)*EHMER_MAX);
+  memcpy(p->tonecurves[6][8]+2,tone_500_80dB_SL,sizeof(float)*EHMER_MAX);
+  memcpy(p->tonecurves[6][10]+2,tone_500_100dB_SL,sizeof(float)*EHMER_MAX);
+
+  memcpy(p->tonecurves[8][4]+2,tone_1000_40dB_SL,sizeof(float)*EHMER_MAX);
+  memcpy(p->tonecurves[8][6]+2,tone_1000_60dB_SL,sizeof(float)*EHMER_MAX);
+  memcpy(p->tonecurves[8][8]+2,tone_1000_80dB_SL,sizeof(float)*EHMER_MAX);
+  memcpy(p->tonecurves[8][10]+2,tone_1000_100dB_SL,sizeof(float)*EHMER_MAX);
+
+  memcpy(p->tonecurves[10][4]+2,tone_2000_40dB_SL,sizeof(float)*EHMER_MAX);
+  memcpy(p->tonecurves[10][6]+2,tone_2000_60dB_SL,sizeof(float)*EHMER_MAX);
+  memcpy(p->tonecurves[10][8]+2,tone_2000_80dB_SL,sizeof(float)*EHMER_MAX);
+  memcpy(p->tonecurves[10][10]+2,tone_2000_100dB_SL,sizeof(float)*EHMER_MAX);
+
+  memcpy(p->tonecurves[12][4]+2,tone_4000_40dB_SL,sizeof(float)*EHMER_MAX);
+  memcpy(p->tonecurves[12][6]+2,tone_4000_60dB_SL,sizeof(float)*EHMER_MAX);
+  memcpy(p->tonecurves[12][8]+2,tone_4000_80dB_SL,sizeof(float)*EHMER_MAX);
+  memcpy(p->tonecurves[12][10]+2,tone_4000_100dB_SL,sizeof(float)*EHMER_MAX);
+
+  memcpy(p->tonecurves[14][4]+2,tone_8000_40dB_SL,sizeof(float)*EHMER_MAX);
+  memcpy(p->tonecurves[14][6]+2,tone_8000_60dB_SL,sizeof(float)*EHMER_MAX);
+  memcpy(p->tonecurves[14][8]+2,tone_8000_80dB_SL,sizeof(float)*EHMER_MAX);
+  memcpy(p->tonecurves[14][10]+2,tone_8000_100dB_SL,sizeof(float)*EHMER_MAX);
+
+  memcpy(p->tonecurves[16][4]+2,tone_8000_40dB_SL,sizeof(float)*EHMER_MAX);
+  memcpy(p->tonecurves[16][6]+2,tone_8000_60dB_SL,sizeof(float)*EHMER_MAX);
+  memcpy(p->tonecurves[16][8]+2,tone_8000_80dB_SL,sizeof(float)*EHMER_MAX);
+  memcpy(p->tonecurves[16][10]+2,tone_8000_100dB_SL,sizeof(float)*EHMER_MAX);
+
+  /* interpolate curves between */
+  for(i=1;i<P_BANDS;i+=2)
+    for(j=4;j<P_LEVELS;j+=2){
+      memcpy(p->tonecurves[i][j]+2,p->tonecurves[i-1][j]+2,EHMER_MAX*sizeof(float));
+      /*interp_curve(p->tonecurves[i][j],
+                  p->tonecurves[i-1][j],
+                  p->tonecurves[i+1][j],.5);*/
+      min_curve(p->tonecurves[i][j]+2,p->tonecurves[i+1][j]+2);
+    }
+
+  /* set up the final curves */
+  for(i=0;i<P_BANDS;i++)
+    setup_curve(p->tonecurves[i],i,vi->toneatt[i]);
+
+  /* set up attenuation levels */
+  for(i=0;i<P_BANDS;i++)
+    for(j=0;j<P_LEVELS;j++){
+      p->peakatt[i][j]=p->vi->peakatt[i][j];
+    }
+
+  /* set up rolling noise median */
+  for(i=0;i<n;i++){
+    float halfoc=toOC((i+.5)*rate/(2.*n))*2.+2.;
+    int inthalfoc;
+    float del;
+    
+    if(halfoc<0)halfoc=0;
+    if(halfoc>=P_BANDS-1)halfoc=P_BANDS-1;
+    inthalfoc=(int)halfoc;
+    del=halfoc-inthalfoc;
+
+    p->noisemedian[i]=
+      p->vi->noisemedian[inthalfoc*2]*(1.-del) + 
+      p->vi->noisemedian[inthalfoc*2+2]*del;
+    p->noiseoffset[i]=
+      p->vi->noisemedian[inthalfoc*2+1]*(1.-del) + 
+      p->vi->noisemedian[inthalfoc*2+3]*del;
+  }
+  /*_analysis_output("mediancurve",0,p->noisemedian,n,0,0);*/
+}
+
+void _vp_psy_clear(vorbis_look_psy *p){
+  int i,j;
+  if(p){
+    if(p->ath)_ogg_free(p->ath);
+    if(p->octave)_ogg_free(p->octave);
+    if(p->bark)_ogg_free(p->bark);
+    if(p->tonecurves){
+      for(i=0;i<P_BANDS;i++){
+       for(j=0;j<P_LEVELS;j++){
+         _ogg_free(p->tonecurves[i][j]);
+       }
+       _ogg_free(p->tonecurves[i]);
+       _ogg_free(p->peakatt[i]);
+      }
+      _ogg_free(p->tonecurves);
+      _ogg_free(p->noisemedian);
+      _ogg_free(p->noiseoffset);
+      _ogg_free(p->peakatt);
     }
-    lroll=fromdB(roll);
-    if(m[i]<lroll)m[i]=lroll;
+    memset(p,0,sizeof(vorbis_look_psy));
   }
 }
 
-/* s must be padded at the end with m-1 zeroes */
-static void time_convolve(double *s,double *r,int n,int m){
+/* octave/(8*eighth_octave_lines) x scale and dB y scale */
+static void seed_curve(float *seed,
+                     float **curves,
+                     float amp,
+                     int oc,int n,int linesper,float dBoffset){
   int i;
-  
-  for(i=0;i<n;i++){
-    int j;
-    double acc=0;
+  long seedptr;
+  float *posts,*curve;
+
+  int choice=(int)((amp+dBoffset)*.1f);
+  choice=max(choice,0);
+  choice=min(choice,P_LEVELS-1);
+  posts=curves[choice];
+  curve=posts+2;
+  seedptr=oc+(posts[0]-16)*linesper-(linesper>>1);
+
+  for(i=posts[0];i<posts[1];i++){
+    if(seedptr>0){
+      float lin=amp+curve[i];
+      if(seed[seedptr]<lin)seed[seedptr]=lin;
+    }
+    seedptr+=linesper;
+    if(seedptr>=n)break;
+  }
+}
 
-    for(j=0;j<m;j++)
-      acc+=s[i+j]*r[m-j-1];
+static void seed_peak(float *seed,
+                     float *att,
+                     float amp,
+                     int oc,
+                     int linesper,
+                     float dBoffset){
+  long seedptr;
+
+  int choice=(int)((amp+dBoffset)*.1f);
+  choice=max(choice,0);
+  choice=min(choice,P_LEVELS-1);
+  seedptr=oc-(linesper>>1);
+
+  amp+=att[choice];
+  if(seed[seedptr]<amp)seed[seedptr]=amp;
 
-    s[i]=acc;
-  }
 }
 
-/*************************************************************************/
-/* Continuous balance analysis/synthesis *********************************/
+static void seed_loop(vorbis_look_psy *p,
+                     float ***curves,
+                     float **att,
+                     float *f, 
+                     float *flr,
+                     float *minseed,
+                     float *maxseed,
+                     float specmax){
+  vorbis_info_psy *vi=p->vi;
+  long n=p->n,i;
+  float dBoffset=vi->max_curve_dB-specmax;
 
+  /* prime the working vector with peak values */
 
-/* Compute the average continual spectral balance of the given vectors
-   (in radians); encode into LPC coefficients */
+  for(i=0;i<n;i++){
+      float max=f[i];
+      long oc=p->octave[i];
+      while(i+1<n && p->octave[i+1]==oc){
+       i++;
+       if(f[i]>max)max=f[i];
+      }
 
-double _vp_balance_compute(double *A, double *B, double *lpc,lpc_lookup *vb){
-  /* correlate in time (the response function is small).  Log
-     frequency scale, small mapping */
+      if(max>flr[i]){
+       oc=oc>>p->shiftoc;
+       if(oc>=P_BANDS)oc=P_BANDS-1;
+       if(oc<0)oc=0;
+       if(vi->tonemaskp)
+         seed_curve(minseed,
+                    curves[oc],
+                    max,
+                    p->octave[i]-p->firstoc,
+                    p->total_octave_lines,
+                    p->eighth_octave_lines,
+                    dBoffset);
+       if(vi->peakattp)
+         seed_peak(maxseed,
+                   att[oc],
+                   max,
+                   p->octave[i]-p->firstoc,
+                   p->eighth_octave_lines,
+                   dBoffset);
+      }
+  }
+}
 
-  int n=vb->n;
-  int mapped=vb->ln;
+static void bound_loop(vorbis_look_psy *p,
+                      float *f, 
+                      float *seeds,
+                      float *flr,
+                      float att){
+  long n=p->n,i;
 
-  /* 256/15 are arbitrary but unimportant to decoding */
-  int resp=15;
-  int i;
+  long off=(p->eighth_octave_lines>>1)+p->firstoc;
+  long *ocp=p->octave;
 
-  /* This is encode side. Don't think too hard about it */
-  
-  double workA[mapped+resp];
-  double workB[mapped+resp];
-  double p[mapped];
-  double workC[resp];
+  for(i=0;i<n;i++){
+    long oc=ocp[i]-off;
+    float v=f[i]+att;
+    if(seeds[oc]<v)seeds[oc]=v;
+  }
+}
 
-  memset(workA,0,sizeof(workA));
-  memset(workB,0,sizeof(workB));
-  memset(workC,0,sizeof(workC));
+static void seed_chase(float *seeds, int linesper, long n){
+  long  *posstack=alloca(n*sizeof(long));
+  float *ampstack=alloca(n*sizeof(float));
+  long   stack=0;
+  long   pos=0;
+  long   i;
 
   for(i=0;i<n;i++){
-    int j=vb->bscale[i]+(resp>>1);
-    double mag_sq=A[i]*A[i]+B[i]*B[i];
-    double phi;
-
-    if(B[i]==0)
-      phi=M_PI/2.;
-    else{
-      phi=atan(A[i]/B[i]);
-      if((A[i]<0 && B[i]>0)||
-        (A[i]>0 && B[i]<0)){
-       /* rotate II and IV into the first quadrant.  III is already there */
-       phi+=M_PI/2;
+    if(stack<2){
+      posstack[stack]=i;
+      ampstack[stack++]=seeds[i];
+    }else{
+      while(1){
+       if(seeds[i]<ampstack[stack-1]){
+         posstack[stack]=i;
+         ampstack[stack++]=seeds[i];
+         break;
+       }else{
+         if(i<posstack[stack-1]+linesper){
+           if(stack>1 && ampstack[stack-1]<=ampstack[stack-2] &&
+              i<posstack[stack-2]+linesper){
+             /* we completely overlap, making stack-1 irrelevant.  pop it */
+             stack--;
+             continue;
+           }
+         }
+         posstack[stack]=i;
+         ampstack[stack++]=seeds[i];
+         break;
+
+       }
       }
     }
+  }
 
-    workA[j]+=mag_sq*sin(phi);
-    workB[j]+=mag_sq*cos(phi);
+  /* the stack now contains only the positions that are relevant. Scan
+     'em straight through */
+
+  for(i=0;i<stack;i++){
+    long endpos;
+    if(i<stack-1 && ampstack[i+1]>ampstack[i]){
+      endpos=posstack[i+1];
+    }else{
+      endpos=posstack[i]+linesper+1; /* +1 is important, else bin 0 is
+                                       discarded in short frames */
+    }
+    if(endpos>n)endpos=n;
+    for(;pos<endpos;pos++)
+      seeds[pos]=ampstack[i];
   }
+  
+  /* there.  Linear time.  I now remember this was on a problem set I
+     had in Grad Skool... I didn't solve it at the time ;-) */
+
+}
 
-  /* prepare convolution vector.  Play with a few different shapes */
+/* bleaugh, this is more complicated than it needs to be */
+static void max_seeds(vorbis_look_psy *p,float *minseed,float *maxseed,
+                     float *flr){
+  long   n=p->total_octave_lines;
+  int    linesper=p->eighth_octave_lines;
+  long   linpos=0;
+  long   pos;
+
+  seed_chase(minseed,linesper,n); /* for masking */
+  seed_chase(maxseed,linesper,n); /* for peak att */
+  pos=p->octave[0]-p->firstoc-(linesper>>1);
+  while(linpos+1<p->n){
+    float min=minseed[pos];
+    float max=maxseed[pos];
+    long end=((p->octave[linpos]+p->octave[linpos+1])>>1)-p->firstoc;
+    while(pos+1<=end){
+      pos++;
+      if((minseed[pos]>NEGINF && minseed[pos]<min) || min==NEGINF)
+       min=minseed[pos];
+      if(maxseed[pos]>max)max=maxseed[pos];
+    }
+    if(max<min)max=min;
+    
+    /* seed scale is log.  Floor is linear.  Map back to it */
+    end=pos+p->firstoc;
+    for(;linpos<p->n && p->octave[linpos]<=end;linpos++)
+      if(flr[linpos]<max)flr[linpos]=max;
+  }
   
-  for(i=0;i<resp;i++){
-    workC[i]=sin(M_PI*(i+1)/(float)(resp+1));
-    workC[i]*=workC[i];
+  {
+    float min=minseed[p->total_octave_lines-1];
+    float max=maxseed[p->total_octave_lines-1];
+    if(max<min)max=min;
+    for(;linpos<p->n;linpos++)
+      if(flr[linpos]<max)flr[linpos]=max;
   }
+  
+}
 
-  time_convolve(workA,workC,mapped,resp);
-  time_convolve(workB,workC,mapped,resp);
+/* quarter-dB bins */
+#define BIN(x)   ((int)((x)*negFour))
+#define BINdB(x) ((x)*negQuarter)
+#define BINCOUNT (200*4)
+#define LASTBIN  (BINCOUNT-1)
 
-  {
-    double amp1;
+static void bark_noise_median(long n,float *b,float *f,float *noise,
+                             float lowidth,float hiwidth,
+                             int lomin,int himin,
+                             float *thresh,float *off){
+  long i=0,lo=0,hi=0;
+  float bi,threshi;
+  long median=LASTBIN;
+  float negFour = -4.0f;
+  float negQuarter = -0.25f;
+
+   /* these are really integral values, but we store them in floats to
+      avoid excessive float/int conversions, which GCC and MSVC are
+      farily poor at optimizing. */
+
+  float radix[BINCOUNT];
+  float countabove=0;
+  float countbelow=0;
 
-    for(i=0;i<mapped;i++){
-      p[i]=atan2(workA[i],workB[i]);
+  memset(radix,0,sizeof(radix));
+
+  for(i=0;i<n;i++){
+    /* find new lo/hi */
+    bi=b[i]+hiwidth;
+    for(;hi<n && (hi<i+himin || b[hi]<=bi);hi++){
+      int bin=BIN(f[hi]);
+      if(bin>LASTBIN)bin=LASTBIN;
+      if(bin<0)bin=0;
+      radix[bin]++;
+      if(bin<median)
+       countabove++;
+      else
+       countbelow++;
+    }
+    bi=b[i]-lowidth;
+    for(;lo<i && lo+lomin<i && b[lo]<=bi;lo++){
+      int bin=BIN(f[lo]);
+      if(bin>LASTBIN)bin=LASTBIN;
+      if(bin<0)bin=0;
+      radix[bin]--;
+      if(bin<median)
+       countabove--;
+      else
+       countbelow--;
     }
 
-    amp1=sqrt(vorbis_gen_lpc(p,lpc,vb));
+    /* move the median if needed */
+    if(countabove+countbelow){
+      threshi = thresh[i]*(countabove+countbelow);
 
-    return(amp1);
+      while(threshi>countbelow && median>0){
+       median--;
+       countabove-=radix[median];
+       countbelow+=radix[median];
+      }
+
+      while(threshi<(countbelow-radix[median]) &&
+           median<LASTBIN){
+       countabove+=radix[median];
+       countbelow-=radix[median];
+       median++;
+      }
+    }
+    noise[i]=BINdB(median)+off[i];
   }
 
 }
 
-/*void _vp_balance_apply(double *A, double *B, double *lpc, double amp,
-                    lpc_lookup *vb,int divp){
-  int i;
-  for(i=0;i<vb->n;i++){
-    double mag=sqrt(A[i]*A[i]+B[i]*B[i]);
-    double del=vorbis_lpc_magnitude(vb->dscale[i],lpc,vb->m)*amp;
-    double phi=atan2(A[i],B[i]);
+float _vp_compute_mask(vorbis_look_psy *p,
+                     float *fft, 
+                     float *mdct, 
+                     float *flr, 
+                     float *decay,
+                     float specmax){
+  int i,n=p->n;
+  float localmax=NEGINF;
+  static int seq=0;
+
+  float *minseed=alloca(sizeof(float)*p->total_octave_lines);
+  float *maxseed=alloca(sizeof(float)*p->total_octave_lines);
+  for(i=0;i<p->total_octave_lines;i++)minseed[i]=maxseed[i]=NEGINF;
+
+  /* go to dB scale. Also find the highest peak so we know the limits */
+  for(i=0;i<n;i++){
+    fft[i]=todB(fft[i]);
+    if(fft[i]>localmax)localmax=fft[i];
+  }
+  if(specmax<localmax)specmax=localmax;
 
-    if(divp)
-      phi-=del;
-    else
-      phi+=del;
 
-    A[i]=mag*sin(phi);
-    B[i]=mag*cos(phi);
+  for(i=0;i<n;i++){
+    mdct[i]=todB(mdct[i]);
+  }
+
+  _analysis_output("mdct",seq,mdct,n,0,0);
+  _analysis_output("fft",seq,fft,n,0,0);
+
+  /* noise masking */
+  if(p->vi->noisemaskp){
+    bark_noise_median(n,p->bark,mdct,flr,
+                     p->vi->noisewindowlo,
+                     p->vi->noisewindowhi,
+                     p->vi->noisewindowlomin,
+                     p->vi->noisewindowhimin,
+                     p->noisemedian,
+                     p->noiseoffset);
+    /* suppress any noise curve > specmax+p->vi->noisemaxsupp */
+    for(i=0;i<n;i++)
+      if(flr[i]>specmax+p->vi->noisemaxsupp)
+       flr[i]=specmax+p->vi->noisemaxsupp;
+    _analysis_output("noise",seq,flr,n,0,0);
+  }else{
+    for(i=0;i<n;i++)flr[i]=NEGINF;
+  }
+
+  /* set the ATH (floating below localmax, not global max by a
+     specified att) */
+  if(p->vi->athp){
+    float att=localmax+p->vi->ath_adjatt;
+    if(att<p->vi->ath_maxatt)att=p->vi->ath_maxatt;
+
+    for(i=0;i<n;i++){
+      float av=p->ath[i]+att;
+      if(av>flr[i])flr[i]=av;
+    }
+  }
+
+  _analysis_output("ath",seq,flr,n,0,0);
+
+  /* tone/peak masking */
+
+  /* XXX apply decay to the fft here */
+
+  seed_loop(p,p->tonecurves,p->peakatt,fft,flr,minseed,maxseed,specmax);
+  bound_loop(p,mdct,maxseed,flr,p->vi->bound_att_dB);
+  _analysis_output("minseed",seq,minseed,p->total_octave_lines,0,0);
+  _analysis_output("maxseed",seq,maxseed,p->total_octave_lines,0,0);
+  max_seeds(p,minseed,maxseed,flr);
+  _analysis_output("final",seq,flr,n,0,0);
+
+  /* doing this here is clean, but we need to find a faster way to do
+     it than to just tack it on */
+
+  for(i=0;i<n;i++)if(mdct[i]>=flr[i])break;
+  if(i==n)for(i=0;i<n;i++)flr[i]=NEGINF;
+
+
+  seq++;
+
+  return(specmax);
+}
+
+
+/* this applies the floor and (optionally) tries to preserve noise
+   energy in low resolution portions of the spectrum */
+/* f and flr are *linear* scale, not dB */
+void _vp_apply_floor(vorbis_look_psy *p,float *f, float *flr){
+  float *work=alloca(p->n*sizeof(float));
+  int j;
+
+  /* subtract the floor */
+  for(j=0;j<p->n;j++){
+    if(flr[j]<=0)
+      work[j]=0.f;
+    else
+      work[j]=f[j]/flr[j];
   }
-  }*/
+
+  memcpy(f,work,p->n*sizeof(float));
+}
+
+float _vp_ampmax_decay(float amp,vorbis_dsp_state *vd){
+  vorbis_info *vi=vd->vi;
+  codec_setup_info *ci=vi->codec_setup;
+  int n=ci->blocksizes[vd->W]/2;
+  float secs=(float)n/vi->rate;
+
+  amp+=secs*ci->ampmax_att_per_sec;
+  if(amp<-9999)amp=-9999;
+  return(amp);
+}
+
+
+