motion.c

avi2mpg1_src 中包含了mpeg1编码的源程序

 *curref：当前的重建图像帧（用来根据第一个场预测第二个场）
 *sxf，syf：前向搜索窗口
 *sxb，syb：后向搜索窗口
 *mbi：指向宏块信息结构体的指针
 *secondfield：指示一帧图像的第二个场
 *ipflag：指示当前P图像帧是由I图像帧所预测产生的

 *输出结果mbi->
 *mb_type: 0, MB_INTRA, MB_FORWARD, MB_BACKWARD, MB_FORWARD|MB_BACKWARD
 *MV[][][]: 运动向量 (场格式)
 *mv_field_sel: 顶部/底部场
 *motion_type: MC_FIELD, MC_16X8

 */
static void field_ME(oldorg,neworg,oldref,newref,cur,curref,i,j,
  sxf,syf,sxb,syb,mbi,secondfield,ipflag)
unsigned char *oldorg,*neworg,*oldref,*newref,*cur,*curref;
int i,j,sxf,syf,sxb,syb;
struct mbinfo *mbi;
int secondfield,ipflag;
{
  int w2;
  unsigned char *mb, *toporg, *topref, *botorg, *botref;
  int var,vmc,v0,dmc,dmcfieldi,dmc8i;
  int imin,jmin,imin8u,jmin8u,imin8l,jmin8l,dmcfield,dmc8,sel,sel8u,sel8l;
  int iminf,jminf,imin8uf,jmin8uf,imin8lf,jmin8lf,dmcfieldf,dmc8f,self,sel8uf,sel8lf;
  int iminr,jminr,imin8ur,jmin8ur,imin8lr,jmin8lr,dmcfieldr,dmc8r,selr,sel8ur,sel8lr;
  int imins,jmins,ds,imindmv,jmindmv,vmc_dp,dmc_dp;

  w2 = width<<1;

  mb = cur + i + w2*j;
  if (pict_struct==BOTTOM_FIELD)
    mb += width;

  var = variance(mb,w2);

  if (pict_type==I_TYPE)
    mbi->mb_type = MB_INTRA;
  else if (pict_type==P_TYPE)
  {
    toporg = oldorg;
    topref = oldref;
    botorg = oldorg + width;
    botref = oldref + width;

    if (secondfield)
    {
      
      if (pict_struct==TOP_FIELD)
      {
        
        botorg = cur + width;
        botref = curref + width;
      }
      else
      {
        
        toporg = cur;
        topref = curref;
      }
    }

    field_estimate(toporg,topref,botorg,botref,mb,i,j,sxf,syf,ipflag,
                   &imin,&jmin,&imin8u,&jmin8u,&imin8l,&jmin8l,
                   &dmcfield,&dmc8,&sel,&sel8u,&sel8l,&imins,&jmins,&ds);

    if (M==1 && !ipflag)  
      dpfield_estimate(topref,botref,mb,i,j,imins,jmins,&imindmv,&jmindmv,
        &dmc_dp,&vmc_dp);

    
    if (M==1 && !ipflag && dmc_dp<dmc8 && dmc_dp<dmcfield)
    {
      
      mbi->motion_type = MC_DMV;
      dmc = dmc_dp;     
      vmc = vmc_dp;     

    }
    else if (dmc8<dmcfield)
    {
       /* 16x8 预测 */
      mbi->motion_type = MC_16X8;
      /* 上半部分宏块*/
      vmc = dist2((sel8u?botref:topref) + (imin8u>>1) + w2*(jmin8u>>1),
                  mb,w2,imin8u&1,jmin8u&1,8);
      /* lower half block */
      vmc+= dist2((sel8l?botref:topref) + (imin8l>>1) + w2*(jmin8l>>1),
                  mb+8*w2,w2,imin8l&1,jmin8l&1,8);
    }
    else
    {
      /* 下半部分宏块 */
      mbi->motion_type = MC_FIELD;
      vmc = dist2((sel?botref:topref) + (imin>>1) + w2*(jmin>>1),
                  mb,w2,imin&1,jmin&1,16);
    }

    /* 选择帧内编码还是非帧内编码*/
    if (vmc>var && vmc>=9*256)
      mbi->mb_type = MB_INTRA;
    else
    {
      
      if (!ipflag)
        v0 = dist2(((pict_struct==BOTTOM_FIELD)?botref:topref) + i + w2*j,
                   mb,w2,0,0,16);
      if (ipflag || (4*v0>5*vmc && v0>=9*256))
      {
        var = vmc;
        mbi->mb_type = MB_FORWARD;
        if (mbi->motion_type==MC_FIELD)
        {
          mbi->MV[0][0][0] = imin - (i<<1);
          mbi->MV[0][0][1] = jmin - (j<<1);
          mbi->mv_field_sel[0][0] = sel;
        }
        else if (mbi->motion_type==MC_DMV)
        {
          
          mbi->MV[0][0][0] = imins - (i<<1);
          mbi->MV[0][0][1] = jmins - (j<<1);

         
          mbi->dmvector[0] = imindmv;
          mbi->dmvector[1] = jmindmv;
        }
        else
        {
          mbi->MV[0][0][0] = imin8u - (i<<1);
          mbi->MV[0][0][1] = jmin8u - (j<<1);
          mbi->MV[1][0][0] = imin8l - (i<<1);
          mbi->MV[1][0][1] = jmin8l - ((j+8)<<1);
          mbi->mv_field_sel[0][0] = sel8u;
          mbi->mv_field_sel[1][0] = sel8l;
        }
      }
      else
      {
        
        var = v0;
        mbi->mb_type = 0;
        mbi->motion_type = MC_FIELD;
        mbi->MV[0][0][0] = 0;
        mbi->MV[0][0][1] = 0;
        mbi->mv_field_sel[0][0] = (pict_struct==BOTTOM_FIELD);
      }
    }
  }
  else /* 如果为B帧图像*/
  {
    /* 前向预测*/
    field_estimate(oldorg,oldref,oldorg+width,oldref+width,mb,
                   i,j,sxf,syf,0,
                   &iminf,&jminf,&imin8uf,&jmin8uf,&imin8lf,&jmin8lf,
                   &dmcfieldf,&dmc8f,&self,&sel8uf,&sel8lf,&imins,&jmins,&ds);

     /*后向预测*/
    field_estimate(neworg,newref,neworg+width,newref+width,mb,
                   i,j,sxb,syb,0,
                   &iminr,&jminr,&imin8ur,&jmin8ur,&imin8lr,&jmin8lr,
                   &dmcfieldr,&dmc8r,&selr,&sel8ur,&sel8lr,&imins,&jmins,&ds);

     /* 计算双向预测的距离*/
    /* 场 */
    dmcfieldi = bdist1(oldref + (self?width:0) + (iminf>>1) + w2*(jminf>>1),
                       newref + (selr?width:0) + (iminr>>1) + w2*(jminr>>1),
                       mb,w2,iminf&1,jminf&1,iminr&1,jminr&1,16);

    /* 16x8 上半块*/
    dmc8i = bdist1(oldref + (sel8uf?width:0) + (imin8uf>>1) + w2*(jmin8uf>>1),
                   newref + (sel8ur?width:0) + (imin8ur>>1) + w2*(jmin8ur>>1),
                   mb,w2,imin8uf&1,jmin8uf&1,imin8ur&1,jmin8ur&1,8);

    /* 16x8 下半块 */
    dmc8i+= bdist1(oldref + (sel8lf?width:0) + (imin8lf>>1) + w2*(jmin8lf>>1),
                   newref + (sel8lr?width:0) + (imin8lr>>1) + w2*(jmin8lr>>1),
                   mb+8*w2,w2,imin8lf&1,jmin8lf&1,imin8lr&1,jmin8lr&1,8);

   /*选择距离最小的预测类型*/
    if (dmcfieldi<dmc8i && dmcfieldi<dmcfieldf && dmcfieldi<dmc8f
        && dmcfieldi<dmcfieldr && dmcfieldi<dmc8r)
    {
      /* 内插*/
      mbi->mb_type = MB_FORWARD|MB_BACKWARD;
      mbi->motion_type = MC_FIELD;
      vmc = bdist2(oldref + (self?width:0) + (iminf>>1) + w2*(jminf>>1),
                   newref + (selr?width:0) + (iminr>>1) + w2*(jminr>>1),
                   mb,w2,iminf&1,jminf&1,iminr&1,jminr&1,16);
    }
    else if (dmc8i<dmcfieldf && dmc8i<dmc8f
             && dmc8i<dmcfieldr && dmc8i<dmc8r)
    {
      /* 16x8, 内插*/
      mbi->mb_type = MB_FORWARD|MB_BACKWARD;
      mbi->motion_type = MC_16X8;

      /* 上半块 */
      vmc = bdist2(oldref + (sel8uf?width:0) + (imin8uf>>1) + w2*(jmin8uf>>1),
                   newref + (sel8ur?width:0) + (imin8ur>>1) + w2*(jmin8ur>>1),
                   mb,w2,imin8uf&1,jmin8uf&1,imin8ur&1,jmin8ur&1,8);

      /* 下半块 */
      vmc+= bdist2(oldref + (sel8lf?width:0) + (imin8lf>>1) + w2*(jmin8lf>>1),
                   newref + (sel8lr?width:0) + (imin8lr>>1) + w2*(jmin8lr>>1),
                   mb+8*w2,w2,imin8lf&1,jmin8lf&1,imin8lr&1,jmin8lr&1,8);
    }
    else if (dmcfieldf<dmc8f && dmcfieldf<dmcfieldr && dmcfieldf<dmc8r)
    {
      
      mbi->mb_type = MB_FORWARD;
      mbi->motion_type = MC_FIELD;
      vmc = dist2(oldref + (self?width:0) + (iminf>>1) + w2*(jminf>>1),
                  mb,w2,iminf&1,jminf&1,16);
    }
    else if (dmc8f<dmcfieldr && dmc8f<dmc8r)
    {
       /* 16x8, 前向*/
      mbi->mb_type = MB_FORWARD;
      mbi->motion_type = MC_16X8;

      
      vmc = dist2(oldref + (sel8uf?width:0) + (imin8uf>>1) + w2*(jmin8uf>>1),
                  mb,w2,imin8uf&1,jmin8uf&1,8);

     
      vmc+= dist2(oldref + (sel8lf?width:0) + (imin8lf>>1) + w2*(jmin8lf>>1),
                  mb+8*w2,w2,imin8lf&1,jmin8lf&1,8);
    }
    else if (dmcfieldr<dmc8r)
    {
      
      mbi->mb_type = MB_BACKWARD;
      mbi->motion_type = MC_FIELD;
      vmc = dist2(newref + (selr?width:0) + (iminr>>1) + w2*(jminr>>1),
                  mb,w2,iminr&1,jminr&1,16);
    }
    else
    {
      
      mbi->mb_type = MB_BACKWARD;
      mbi->motion_type = MC_16X8;

     
      vmc = dist2(newref + (sel8ur?width:0) + (imin8ur>>1) + w2*(jmin8ur>>1),
                  mb,w2,imin8ur&1,jmin8ur&1,8);

      vmc+= dist2(newref + (sel8lr?width:0) + (imin8lr>>1) + w2*(jmin8lr>>1),
                  mb+8*w2,w2,imin8lr&1,jmin8lr&1,8);
    }

   
    if (vmc>var && vmc>=9*256)
      mbi->mb_type = MB_INTRA;
    else
    {
      var = vmc;
      if (mbi->motion_type==MC_FIELD)
      {
        /* 前向 */
        mbi->MV[0][0][0] = iminf - (i<<1);
        mbi->MV[0][0][1] = jminf - (j<<1);
        mbi->mv_field_sel[0][0] = self;
        /* 后向 */
        mbi->MV[0][1][0] = iminr - (i<<1);
        mbi->MV[0][1][1] = jminr - (j<<1);
        mbi->mv_field_sel[0][1] = selr;
      }
      else /* MC_16X8 */
      {
        /* 前向 */
        mbi->MV[0][0][0] = imin8uf - (i<<1);
        mbi->MV[0][0][1] = jmin8uf - (j<<1);
        mbi->mv_field_sel[0][0] = sel8uf;
        mbi->MV[1][0][0] = imin8lf - (i<<1);
        mbi->MV[1][0][1] = jmin8lf - ((j+8)<<1);
        mbi->mv_field_sel[1][0] = sel8lf;
        /* 后向 */
        mbi->MV[0][1][0] = imin8ur - (i<<1);
        mbi->MV[0][1][1] = jmin8ur - (j<<1);
        mbi->mv_field_sel[0][1] = sel8ur;
        mbi->MV[1][1][0] = imin8lr - (i<<1);
        mbi->MV[1][1][1] = jmin8lr - ((j+8)<<1);
        mbi->mv_field_sel[1][1] = sel8lr;
      }
    }
  }

  mbi->var = var;
}

/*
 * 帧图像运动估计
 *
 
 */
static void frame_estimate(org,ref,mb,i,j,sx,sy,
  iminp,jminp,imintp,jmintp,iminbp,jminbp,dframep,dfieldp,tselp,bselp,
  imins,jmins)
unsigned char *org,*ref,*mb;
int i,j,sx,sy;
int *iminp,*jminp;
int *imintp,*jmintp,*iminbp,*jminbp;
int *dframep,*dfieldp;
int *tselp,*bselp;
int imins[2][2],jmins[2][2];
{
  int dt,db,dmint,dminb;
  int imint,iminb,jmint,jminb;

  /* frame prediction */
  *dframep = fullsearch(org,ref,mb,width,i,j,sx,sy,16,width,height,
                        iminp,jminp);

  /* predict top field from top field */
  dt = fullsearch(org,ref,mb,width<<1,i,j>>1,sx,sy>>1,8,width,height>>1,
                  &imint,&jmint);

  /* predict top field from bottom field */
  db = fullsearch(org+width,ref+width,mb,width<<1,i,j>>1,sx,sy>>1,8,width,height>>1,
                  &iminb,&jminb);

  imins[0][0] = imint;
  jmins[0][0] = jmint;
  imins[1][0] = iminb;
  jmins[1][0] = jminb;

  /* select prediction for top field */
  if (dt<=db)
  {
    dmint=dt; *imintp=imint; *jmintp=jmint; *tselp=0;
  }
  else
  {
    dmint=db; *imintp=iminb; *jmintp=jminb; *tselp=1;
  }

  /* predict bottom field from top field */
  dt = fullsearch(org,ref,mb+width,width<<1,i,j>>1,sx,sy>>1,8,width,height>>1,
                  &imint,&jmint);

  /* predict bottom field from bottom field */
  db = fullsearch(org+width,ref+width,mb+width,width<<1,i,j>>1,sx,sy>>1,8,width,height>>1,
                  &iminb,&jminb);

  imins[0][1] = imint;
  jmins[0][1] = jmint;
  imins[1][1] = iminb;
  jmins[1][1] = jminb;

  /* select prediction for bottom field */
  if (db<=dt)
  {
    dminb=db; *iminbp=iminb; *jminbp=jminb; *bselp=1;
  }
  else
  {
    dminb=dt; *iminbp=imint; *jminbp=jmint; *bselp=0;
  }

  *dfieldp=dmint+dminb;
}

/*
 * 场图片运动预测程序
 *
 * toporg：原始上半部分场地址
 *topref：重建的上半部分场地址
 *botorg：原始下半部分参考场地址
 *botref：重建的下半部分参考场的地址
 *mb：待匹配的宏块
 *i，j：宏块的位置（即搜索窗口的中心）
 *iminp，jminp，selp，dfieldp：最佳预测场的位置和距离
 *imin8up，jmin8up，sel8up：上半部分宏块的最佳预测的位置
 *imin8lp，jmin8lp，sel8lp：下半部分宏块的最佳预测的位置
 *d8p：最佳16×8的预测块的距离
 *iminsp，jminsp，dsp：最佳同奇偶性预测场的位置和距离
 */

static void field_estimate(toporg,topref,botorg,botref,mb,i,j,sx,sy,ipflag,
  iminp,jminp,imin8up,jmin8up,imin8lp,jmin8lp,dfieldp,d8p,selp,sel8up,sel8lp,
  iminsp,jminsp,dsp)
unsigned char *toporg, *topref, *botorg, *botref, *mb;
int i,j,sx,sy;
int ipflag;
int *iminp, *jminp;
int *imin8up, *jmin8up, *imin8lp, *jmin8lp;
int *dfieldp,*d8p;
int *selp, *sel8up, *sel8lp;
int *iminsp, *jminsp, *dsp;
{
  int dt, db, imint, jmint, iminb, jminb, notop, nobot;

  /* 如果ipflag为1则仅从对偶场预测 */
  notop = ipflag && (pict_struct==TOP_FIELD);
  nobot = ipflag && (pict_struct==BOTTOM_FIELD);

   /*场预测*/

  /* 从上半部分场预测当前场 */
  if (notop)
    dt = 65536; 
  else
    dt = fullsearch(toporg,topref,mb,width<<1,
                    i,j,sx,sy>>1,16,width,height>>1,
                    &imint,&jmint);

   /* 从下半部分场预测当前场*/
  if (nobot)
    db = 65536; 
  else
    db = fullsearch(botorg,botref,mb,width<<1,
                    i,j,sx,sy>>1,16,width,height>>1,
                    &iminb,&jminb);

  if (pict_struct==TOP_FIELD)
  {
    *iminsp = imint; *jminsp = jmint; *dsp = dt;
  }
  else
  {