psy.c

OGG文件格式音频数解压缩SDK.现在OGG文件格式在一些游戏开发中使用的比较多.

  int seedptr;
  const float *posts,*curve;

  int choice=(int)((amp+dBoffset-P_LEVEL_0)*.1f);
  choice=max(choice,0);
  choice=min(choice,P_LEVELS-1);
  posts=curves[choice];
  curve=posts+2;
  post1=(int)posts[1];
  seedptr=(int)(oc+(posts[0]-EHMER_OFFSET)*linesper-(linesper>>1));

  for(i=(int)posts[0];i<post1;i++){
    if(seedptr>0){
      float lin=amp+curve[i];
      if(seed[seedptr]<lin)seed[seedptr]=lin;
    }
    seedptr+=linesper;
    if(seedptr>=n)break;
  }
}

static void seed_loop(vorbis_look_psy *p,
		      const float ***curves,
		      const float *f, 
		      const float *flr,
		      float *seed,
		      float specmax){
  vorbis_info_psy *vi=p->vi;
  ogg_int32_t n=p->n,i;
  float dBoffset=vi->max_curve_dB-specmax;

  /* prime the working vector with peak values */

  for(i=0;i<n;i++){
    float max=f[i];
    ogg_int32_t oc=p->octave[i];
    while(i+1<n && p->octave[i+1]==oc){
      i++;
      if(f[i]>max)max=f[i];
    }
    
    if(max+6.f>flr[i]){
      oc=oc>>p->shiftoc;

      if(oc>=P_BANDS)oc=P_BANDS-1;
      if(oc<0)oc=0;

      seed_curve(seed,
		 curves[oc],
		 max,
		 p->octave[i]-p->firstoc,
		 p->total_octave_lines,
		 p->eighth_octave_lines,
		 dBoffset);
    }
  }
}

static void seed_chase(float *seeds, int linesper, ogg_int32_t n){
  ogg_int32_t  *posstack=alloca(n*sizeof(*posstack));
  float *ampstack=alloca(n*sizeof(*ampstack));
  ogg_int32_t   stack=0;
  ogg_int32_t   pos=0;
  ogg_int32_t   i;

  for(i=0;i<n;i++){
    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;

	}
      }
    }
  }

  /* the stack now contains only the positions that are relevant. Scan
     'em straight through */

  for(i=0;i<stack;i++){
    ogg_int32_t 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 ;-) */

}

/* bleaugh, this is more complicated than it needs to be */
#include<stdio.h>
static void max_seeds(vorbis_look_psy *p,
		      float *seed,
		      float *flr){
  ogg_int32_t   n=p->total_octave_lines;
  int    linesper=p->eighth_octave_lines;
  ogg_int32_t   linpos=0;
  ogg_int32_t   pos;

  seed_chase(seed,linesper,n); /* for masking */
 
  pos=p->octave[0]-p->firstoc-(linesper>>1);

  while(linpos+1<p->n){
    float minV=seed[pos];
    ogg_int32_t end=((p->octave[linpos]+p->octave[linpos+1])>>1)-p->firstoc;
    if(minV>p->vi->tone_abs_limit)minV=p->vi->tone_abs_limit;
    while(pos+1<=end){
      pos++;
      if((seed[pos]>NEGINF && seed[pos]<minV) || minV==NEGINF)
	minV=seed[pos];
    }
    
    end=pos+p->firstoc;
    for(;linpos<p->n && p->octave[linpos]<=end;linpos++)
      if(flr[linpos]<minV)flr[linpos]=minV;
  }
  
  {
    float minV=seed[p->total_octave_lines-1];
    for(;linpos<p->n;linpos++)
      if(flr[linpos]<minV)flr[linpos]=minV;
  }
  
}

static void bark_noise_hybridmp(int n,const ogg_int32_t *b,
                                const float *f,
                                float *noise,
                                const float offset,
                                const int fixed)
{
  float *N=alloca(n*sizeof(*N));
  float *X=alloca(n*sizeof(*N));
  float *XX=alloca(n*sizeof(*N));
  float *Y=alloca(n*sizeof(*N));
  float *XY=alloca(n*sizeof(*N));

  float tN, tX, tXX, tY, tXY;
  int i;

  int lo, hi;
  float R, A, B, D;
  float w, x, y;
  
  tN = tX = tXX = tY = tXY = 0.f;

  y = f[0] + offset;
  if (y < 1.f) y = 1.f;

  w = y * y * 0.5f;
    
  tN += w;
  tX += w;
  tY += w * y;

  N[0] = tN;
  X[0] = tX;
  XX[0] = tXX;
  Y[0] = tY;
  XY[0] = tXY;

  for (i = 1, x = 1.f; i < n; i++, x += 1.f) {
    
    y = f[i] + offset;
    if (y < 1.f) y = 1.f;

    w = y * y;
    
    tN += w;
    tX += w * x;
    tXX += w * x * x;
    tY += w * y;
    tXY += w * x * y;

    N[i] = tN;
    X[i] = tX;
    XX[i] = tXX;
    Y[i] = tY;
    XY[i] = tXY;
  }
  
  for (i = 0, x = 0.f;; i++, x += 1.f) {
    
    lo = b[i] >> 16;
    if( lo>=0 ) break;
    hi = b[i] & 0xffff;
    
    tN = N[hi] + N[-lo];
    tX = X[hi] - X[-lo];
    tXX = XX[hi] + XX[-lo];
    tY = Y[hi] + Y[-lo];    
    tXY = XY[hi] - XY[-lo];
    
    A = tY * tXX - tX * tXY;
    B = tN * tXY - tX * tY;
    D = tN * tXX - tX * tX;
    R = (A + x * B) / D;
    if (R < 0.f)
      R = 0.f;
    
    noise[i] = R - offset;
  }
  
  for ( ;; i++, x += 1.f) {
    
    lo = b[i] >> 16;
    hi = b[i] & 0xffff;
    if(hi>=n)break;
    
    tN = N[hi] - N[lo];
    tX = X[hi] - X[lo];
    tXX = XX[hi] - XX[lo];
    tY = Y[hi] - Y[lo];
    tXY = XY[hi] - XY[lo];
    
    A = tY * tXX - tX * tXY;
    B = tN * tXY - tX * tY;
    D = tN * tXX - tX * tX;
    R = (A + x * B) / D;
    if (R < 0.f) R = 0.f;
    
    noise[i] = R - offset;
  }
  for ( ; i < n; i++, x += 1.f) {
    
    R = (A + x * B) / D;
    if (R < 0.f) R = 0.f;
    
    noise[i] = R - offset;
  }
  
  if (fixed <= 0) return;
  
  for (i = 0, x = 0.f;; i++, x += 1.f) {
    hi = i + fixed / 2;
    lo = hi - fixed;
    if(lo>=0)break;

    tN = N[hi] + N[-lo];
    tX = X[hi] - X[-lo];
    tXX = XX[hi] + XX[-lo];
    tY = Y[hi] + Y[-lo];
    tXY = XY[hi] - XY[-lo];
    
    
    A = tY * tXX - tX * tXY;
    B = tN * tXY - tX * tY;
    D = tN * tXX - tX * tX;
    R = (A + x * B) / D;

    if (R - offset < noise[i]) noise[i] = R - offset;
  }
  for ( ;; i++, x += 1.f) {
    
    hi = i + fixed / 2;
    lo = hi - fixed;
    if(hi>=n)break;
    
    tN = N[hi] - N[lo];
    tX = X[hi] - X[lo];
    tXX = XX[hi] - XX[lo];
    tY = Y[hi] - Y[lo];
    tXY = XY[hi] - XY[lo];
    
    A = tY * tXX - tX * tXY;
    B = tN * tXY - tX * tY;
    D = tN * tXX - tX * tX;
    R = (A + x * B) / D;
    
    if (R - offset < noise[i]) noise[i] = R - offset;
  }
  for ( ; i < n; i++, x += 1.f) {
    R = (A + x * B) / D;
    if (R - offset < noise[i]) noise[i] = R - offset;
  }
}

static float FLOOR1_fromdB_INV_LOOKUP[256]={
  0.F, 8.81683e+06F, 8.27882e+06F, 7.77365e+06F, 
  7.29930e+06F, 6.85389e+06F, 6.43567e+06F, 6.04296e+06F, 
  5.67422e+06F, 5.32798e+06F, 5.00286e+06F, 4.69759e+06F, 
  4.41094e+06F, 4.14178e+06F, 3.88905e+06F, 3.65174e+06F, 
  3.42891e+06F, 3.21968e+06F, 3.02321e+06F, 2.83873e+06F, 
  2.66551e+06F, 2.50286e+06F, 2.35014e+06F, 2.20673e+06F, 
  2.07208e+06F, 1.94564e+06F, 1.82692e+06F, 1.71544e+06F, 
  1.61076e+06F, 1.51247e+06F, 1.42018e+06F, 1.33352e+06F, 
  1.25215e+06F, 1.17574e+06F, 1.10400e+06F, 1.03663e+06F, 
  973377.F, 913981.F, 858210.F, 805842.F, 
  756669.F, 710497.F, 667142.F, 626433.F, 
  588208.F, 552316.F, 518613.F, 486967.F, 
  457252.F, 429351.F, 403152.F, 378551.F, 
  355452.F, 333762.F, 313396.F, 294273.F, 
  276316.F, 259455.F, 243623.F, 228757.F, 
  214798.F, 201691.F, 189384.F, 177828.F, 
  166977.F, 156788.F, 147221.F, 138237.F, 
  129802.F, 121881.F, 114444.F, 107461.F, 
  100903.F, 94746.3F, 88964.9F, 83536.2F, 
  78438.8F, 73652.5F, 69158.2F, 64938.1F, 
  60975.6F, 57254.9F, 53761.2F, 50480.6F, 
  47400.3F, 44507.9F, 41792.0F, 39241.9F, 
  36847.3F, 34598.9F, 32487.7F, 30505.3F, 
  28643.8F, 26896.0F, 25254.8F, 23713.7F, 
  22266.7F, 20908.0F, 19632.2F, 18434.2F, 
  17309.4F, 16253.1F, 15261.4F, 14330.1F, 
  13455.7F, 12634.6F, 11863.7F, 11139.7F, 
  10460.0F, 9821.72F, 9222.39F, 8659.64F, 
  8131.23F, 7635.06F, 7169.17F, 6731.70F, 
  6320.93F, 5935.23F, 5573.06F, 5232.99F, 
  4913.67F, 4613.84F, 4332.30F, 4067.94F, 
  3819.72F, 3586.64F, 3367.78F, 3162.28F, 
  2969.31F, 2788.13F, 2617.99F, 2458.24F, 
  2308.24F, 2167.39F, 2035.14F, 1910.95F, 
  1794.35F, 1684.85F, 1582.04F, 1485.51F, 
  1394.86F, 1309.75F, 1229.83F, 1154.78F, 
  1084.32F, 1018.15F, 956.024F, 897.687F, 
  842.910F, 791.475F, 743.179F, 697.830F, 
  655.249F, 615.265F, 577.722F, 542.469F, 
  509.367F, 478.286F, 449.101F, 421.696F, 
  395.964F, 371.803F, 349.115F, 327.812F, 
  307.809F, 289.026F, 271.390F, 254.830F, 
  239.280F, 224.679F, 210.969F, 198.096F, 
  186.008F, 174.658F, 164.000F, 153.993F, 
  144.596F, 135.773F, 127.488F, 119.708F, 
  112.404F, 105.545F, 99.1046F, 93.0572F, 
  87.3788F, 82.0469F, 77.0404F, 72.3394F, 
  67.9252F, 63.7804F, 59.8885F, 56.2341F, 
  52.8027F, 49.5807F, 46.5553F, 43.7144F, 
  41.0470F, 38.5423F, 36.1904F, 33.9821F, 
  31.9085F, 29.9614F, 28.1332F, 26.4165F, 
  24.8045F, 23.2910F, 21.8697F, 20.5352F, 
  19.2822F, 18.1056F, 17.0008F, 15.9634F, 
  14.9893F, 14.0746F, 13.2158F, 12.4094F, 
  11.6522F, 10.9411F, 10.2735F, 9.64662F, 
  9.05798F, 8.50526F, 7.98626F, 7.49894F, 
  7.04135F, 6.61169F, 6.20824F, 5.82941F, 
  5.47370F, 5.13970F, 4.82607F, 4.53158F, 
  4.25507F, 3.99542F, 3.75162F, 3.52269F, 
  3.30774F, 3.10590F, 2.91638F, 2.73842F, 
  2.57132F, 2.41442F, 2.26709F, 2.12875F, 
  1.99885F, 1.87688F, 1.76236F, 1.65482F, 
  1.55384F, 1.45902F, 1.36999F, 1.28640F, 
  1.20790F, 1.13419F, 1.06499F, 1.F
};

void _vp_remove_floor(vorbis_look_psy *p,
		      float *mdct,
		      int *codedflr,