/* quantize.c, quantization / inverse quantization                          *//* Copyright (C) 1996, MPEG Software Simulation Group. All Rights Reserved. *//* * Disclaimer of Warranty * * These software programs are available to the user without any license fee or * royalty on an "as is" basis.  The MPEG Software Simulation Group disclaims * any and all warranties, whether express, implied, or statuary, including any * implied warranties or merchantability or of fitness for a particular * purpose.  In no event shall the copyright-holder be liable for any * incidental, punitive, or consequential damages of any kind whatsoever * arising from the use of these programs. * * This disclaimer of warranty extends to the user of these programs and user's * customers, employees, agents, transferees, successors, and assigns. * * The MPEG Software Simulation Group does not represent or warrant that the * programs furnished hereunder are free of infringement of any third-party * patents. * * Commercial implementations of MPEG-1 and MPEG-2 video, including shareware, * are subject to royalty fees to patent holders.  Many of these patents are * general enough such that they are unavoidable regardless of implementation * design. * */#include <stdio.h>#include "config.h"#include "global.h"static void iquant1_intra _ANSI_ARGS_((short *src, short *dst,  int dc_prec, unsigned char *quant_mat, int mquant));static void iquant1_non_intra _ANSI_ARGS_((short *src, short *dst,  unsigned char *quant_mat, int mquant));/* Test Model 5 quantization * * this quantizer has a bias of 1/8 stepsize towards zero * (except for the DC coefficient) */int quant_intra(src,dst,dc_prec,quant_mat,mquant)short *src, *dst;int dc_prec;unsigned char *quant_mat;int mquant;{  int i;  int x, y, d;  x = src[0];  d = 8>>dc_prec; /* intra_dc_mult */  dst[0] = (x>=0) ? (x+(d>>1))/d : -((-x+(d>>1))/d); /* round(x/d) */  for (i=1; i<64; i++)  {    x = src[i];    d = quant_mat[i];    y = (32*(x>=0 ? x : -x) + (d>>1))/d; /* round(32*x/quant_mat) */    d = (3*mquant+2)>>2;    y = (y+d)/(2*mquant); /* (y+0.75*mquant) / (2*mquant) */    /* clip to syntax limits */    if (y > 255)    {      if (mpeg1)        y = 255;      else if (y > 2047)        y = 2047;    }    dst[i] = (x>=0) ? y : -y;#if 0    /* this quantizer is virtually identical to the above */    if (x<0)      x = -x;    d = mquant*quant_mat[i];    y = (16*x + ((3*d)>>3)) / d;    dst[i] = (src[i]<0) ? -y : y;#endif  }  return 1;}int quant_non_intra(src,dst,quant_mat,mquant)short *src, *dst;unsigned char *quant_mat;int mquant;{  int i;  int x, y, d;  int nzflag;  nzflag = 0;  for (i=0; i<64; i++)  {    x = src[i];    d = quant_mat[i];    y = (32*(x>=0 ? x : -x) + (d>>1))/d; /* round(32*x/quant_mat) */    y /= (2*mquant);    /* clip to syntax limits */    if (y > 255)    {      if (mpeg1)        y = 255;      else if (y > 2047)        y = 2047;    }    if ((dst[i] = (x>=0 ? y : -y)) != 0)      nzflag=1;  }  return nzflag;}/* MPEG-2 inverse quantization */void iquant_intra(src,dst,dc_prec,quant_mat,mquant)short *src, *dst;int dc_prec;unsigned char *quant_mat;int mquant;{  int i, val, sum;  if (mpeg1)    iquant1_intra(src,dst,dc_prec,quant_mat,mquant);  else  {    sum = dst[0] = src[0] << (3-dc_prec);    for (i=1; i<64; i++)    {      val = (int)(src[i]*quant_mat[i]*mquant)/16;      sum+= dst[i] = (val>2047) ? 2047 : ((val<-2048) ? -2048 : val);    }    /* mismatch control */    if ((sum&1)==0)      dst[63]^= 1;  }}void iquant_non_intra(src,dst,quant_mat,mquant)short *src, *dst;unsigned char *quant_mat;int mquant;{  int i, val, sum;  if (mpeg1)    iquant1_non_intra(src,dst,quant_mat,mquant);  else  {    sum = 0;    for (i=0; i<64; i++)    {      val = src[i];      if (val!=0)        val = (int)((2*val+(val>0 ? 1 : -1))*quant_mat[i]*mquant)/32;      sum+= dst[i] = (val>2047) ? 2047 : ((val<-2048) ? -2048 : val);    }    /* mismatch control */    if ((sum&1)==0)      dst[63]^= 1;  }}/* MPEG-1 inverse quantization */static void iquant1_intra(src,dst,dc_prec,quant_mat,mquant)short *src, *dst;int dc_prec;unsigned char *quant_mat;int mquant;{  int i, val;  dst[0] = src[0] << (3-dc_prec);  for (i=1; i<64; i++)  {    val = (int)(src[i]*quant_mat[i]*mquant)/16;    /* mismatch control */    if ((val&1)==0 && val!=0)      val+= (val>0) ? -1 : 1;    /* saturation */    dst[i] = (val>2047) ? 2047 : ((val<-2048) ? -2048 : val);  }}static void iquant1_non_intra(src,dst,quant_mat,mquant)short *src, *dst;unsigned char *quant_mat;int mquant;{  int i, val;  for (i=0; i<64; i++)  {    val = src[i];    if (val!=0)    {      val = (int)((2*val+(val>0 ? 1 : -1))*quant_mat[i]*mquant)/32;      /* mismatch control */      if ((val&1)==0 && val!=0)        val+= (val>0) ? -1 : 1;    }    /* saturation */    dst[i] = (val>2047) ? 2047 : ((val<-2048) ? -2048 : val);  }}