/************************************************************************ *量化器 * ************************************************************************/#include"sim.h"/**********************************************************************
 *
 *	函數名:        Quant
 *	功能:	量化器
 *	
 *	Input:  變換系數、量化系數、量化參數以及量化模式
 *        
 *
 ***********************************************************************/

void Quant(int *coeff, int *qcoeff, int QP, int Mode)
{
  int i;
  int level;
  //如果量化參數不為0，表示量化器有意義
  if (QP) {
    //量化器首先判斷當前幀是否為幀內圖像
    if (Mode == MODE_INTRA || Mode == MODE_INTRA_Q) { 
      qcoeff[0] = mmax(1,mmin(254,coeff[0]/8));
      //量化編碼塊中的所有系數
      for (i = 1; i < 64; i++) {
        level = (abs(coeff[i])) / (2*QP);	
        qcoeff[i] =  mmin(127,mmax(-127,sign(coeff[i]) * level));
      }
    }
	//如果不是幀內圖像，則取系數差進行量化
    else { /* non Intra */
      for (i = 0; i < 64; i++) {
        level = (abs(coeff[i])-QP/2)  / (2*QP);
        qcoeff[i] = mmin(127,mmax(-127,sign(coeff[i]) * level));
      }
    }
  }
  //量化參數為0，系數不量化
  else {
    for (i = 0; i < 64; i++) {
      qcoeff[i] = coeff[i];
    }
  }
  return;
}
/********************************************************************** * *	Name:        Dequant *	功能:	解量化 *	輸入： 重構系數、量化系數、量化參數以及量化模式 ***********************************************************************/void Dequant(int *qcoeff, int *rcoeff, int QP, int Mode)
{
  int i;
  //如果量化參數不為0，表明有量化
  if (QP) {
    for (i = 0; i < 64; i++) {
      if (qcoeff[i]) {
        //量化參數是奇數
        if ((QP % 2) == 1)
          rcoeff[i] = QP * (2*abs(qcoeff[i]) + 1);
        else
          //量化參數是偶數
          rcoeff[i] = QP * (2*abs(qcoeff[i]) + 1) - 1;
        rcoeff[i] = sign(qcoeff[i]) * rcoeff[i];
      }
      //量化系數為0，重構系數也為0
      else
        rcoeff[i] = 0;
    }
    //幀內系數的處理
    if (Mode == MODE_INTRA || Mode == MODE_INTRA_Q) { 
      rcoeff[0] = qcoeff[0]*8;
    }
  }
  //沒有量化，直接賦值
  else {
    for (i = 0; i < 64; i++) {
      rcoeff[i] = qcoeff[i];
    }
  }
  return;
}