motion.c

MPEG2视频编解码程序

/* motion.c, 运动估计函数*/



#include <stdio.h>
#include "config.h"
#include "global.h"

/* private prototypes */

static void frame_ME _ANSI_ARGS_((unsigned char *oldorg, unsigned char *neworg,
  unsigned char *oldref, unsigned char *newref, unsigned char *cur,
  int i, int j, int sxf, int syf, int sxb, int syb, struct mbinfo *mbi));

static void field_ME _ANSI_ARGS_((unsigned char *oldorg, unsigned char *neworg,
  unsigned char *oldref, unsigned char *newref, unsigned char *cur,
  unsigned char *curref, int i, int j, int sxf, int syf, int sxb, int syb,
  struct mbinfo *mbi, int secondfield, int ipflag));

static void frame_estimate _ANSI_ARGS_((unsigned char *org,
  unsigned char *ref, unsigned char *mb,
  int i, int j,
  int sx, int sy, int *iminp, int *jminp, int *imintp, int *jmintp,
  int *iminbp, int *jminbp, int *dframep, int *dfieldp,
  int *tselp, int *bselp, int imins[2][2], int jmins[2][2]));

static void field_estimate _ANSI_ARGS_((unsigned char *toporg,
  unsigned char *topref, unsigned char *botorg, unsigned char *botref,
  unsigned char *mb, int i, int j, int sx, int sy, int ipflag,
  int *iminp, int *jminp, int *imin8up, int *jmin8up, int *imin8lp,
  int *jmin8lp, int *dfieldp, int *d8p, int *selp, int *sel8up, int *sel8lp,
  int *iminsp, int *jminsp, int *dsp));

static void dpframe_estimate _ANSI_ARGS_((unsigned char *ref,
  unsigned char *mb, int i, int j, int iminf[2][2], int jminf[2][2],
  int *iminp, int *jminp, int *imindmvp, int *jmindmvp,
  int *dmcp, int *vmcp));

static void dpfield_estimate _ANSI_ARGS_((unsigned char *topref,
  unsigned char *botref, unsigned char *mb,
  int i, int j, int imins, int jmins, int *imindmvp, int *jmindmvp,
  int *dmcp, int *vmcp));

static int fullsearch _ANSI_ARGS_((unsigned char *org, unsigned char *ref,
  unsigned char *blk,
  int lx, int i0, int j0, int sx, int sy, int h, int xmax, int ymax,
  int *iminp, int *jminp));

static int dist1 _ANSI_ARGS_((unsigned char *blk1, unsigned char *blk2,
  int lx, int hx, int hy, int h, int distlim));

static int dist2 _ANSI_ARGS_((unsigned char *blk1, unsigned char *blk2,
  int lx, int hx, int hy, int h));

static int bdist1 _ANSI_ARGS_((unsigned char *pf, unsigned char *pb,
  unsigned char *p2, int lx, int hxf, int hyf, int hxb, int hyb, int h));

static int bdist2 _ANSI_ARGS_((unsigned char *pf, unsigned char *pb,
  unsigned char *p2, int lx, int hxf, int hyf, int hxb, int hyb, int h));

static int variance _ANSI_ARGS_((unsigned char *p, int lx));

/*
 * 前向和交织帧的运动估计
 *
 *oldorg：前向预测的原始参考图（供P图像和B图像使用）
 *neworg：后向预测的原始参考图（仅供B图像使用）
 *oldref：前向预测的重建图像（P图像和B图像）
 *newref：后向预测的重建图像（B图像）
 *cur：当前原始图像帧（由预测图像产生的）
 *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
 *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
 */
void motion_estimation(oldorg,neworg,oldref,newref,cur,curref,
  sxf,syf,sxb,syb,mbi,secondfield,ipflag)
unsigned char *oldorg,*neworg,*oldref,*newref,*cur,*curref;
int sxf,syf,sxb,syb;
struct mbinfo *mbi;
int secondfield,ipflag;
{
  int i, j;

    /* 对所有的宏块进行循环操作 */
  for (j=0; j<height2; j+=16)
  {
    for (i=0; i<width; i+=16)
    {
		 /*根据图像结构的类型来判断是进行帧预测还是场预测*/     
      if (pict_struct==FRAME_PICTURE)
        frame_ME(oldorg,neworg,oldref,newref,cur,i,j,sxf,syf,sxb,syb,mbi);
      else
        field_ME(oldorg,neworg,oldref,newref,cur,curref,i,j,sxf,syf,sxb,syb,
          mbi,secondfield,ipflag);
      mbi++;
    }

    if (!quiet)
    {
      putc('.',stderr);
      fflush(stderr);
    }
  }
  if (!quiet)
    putc('\n',stderr);
}

static void frame_ME(oldorg,neworg,oldref,newref,cur,i,j,sxf,syf,sxb,syb,mbi)
unsigned char *oldorg,*neworg,*oldref,*newref,*cur;
int i,j,sxf,syf,sxb,syb;
struct mbinfo *mbi;
{
  int imin,jmin,iminf,jminf,iminr,jminr;
  int imint,jmint,iminb,jminb;
  int imintf,jmintf,iminbf,jminbf;
  int imintr,jmintr,iminbr,jminbr;
  int var,v0;
  int dmc,dmcf,dmcr,dmci,vmc,vmcf,vmcr,vmci;
  int dmcfield,dmcfieldf,dmcfieldr,dmcfieldi;
  int tsel,bsel,tself,bself,tselr,bselr;
  unsigned char *mb;
  int imins[2][2],jmins[2][2];
  int imindp,jmindp,imindmv,jmindmv,dmc_dp,vmc_dp;

  mb = cur + i + width*j;

  var = variance(mb,width);

  if (pict_type==I_TYPE)
    mbi->mb_type = MB_INTRA;
  else if (pict_type==P_TYPE)
  {
    if (frame_pred_dct)
    {
      dmc = fullsearch(oldorg,oldref,mb,
                       width,i,j,sxf,syf,16,width,height,&imin,&jmin);
      vmc = dist2(oldref+(imin>>1)+width*(jmin>>1),mb,
                  width,imin&1,jmin&1,16);
      mbi->motion_type = MC_FRAME;
    }
    else
    {
      frame_estimate(oldorg,oldref,mb,i,j,sxf,syf,
        &imin,&jmin,&imint,&jmint,&iminb,&jminb,
        &dmc,&dmcfield,&tsel,&bsel,imins,jmins);

      if (M==1)
        dpframe_estimate(oldref,mb,i,j>>1,imins,jmins,
          &imindp,&jmindp,&imindmv,&jmindmv,&dmc_dp,&vmc_dp);

      /* select between dual prime, frame and field prediction */
      if (M==1 && dmc_dp<dmc && dmc_dp<dmcfield)
      {
        mbi->motion_type = MC_DMV;
        dmc = dmc_dp;
        vmc = vmc_dp;
      }
      else if (dmc<=dmcfield)
      {
        mbi->motion_type = MC_FRAME;
        vmc = dist2(oldref+(imin>>1)+width*(jmin>>1),mb,
                    width,imin&1,jmin&1,16);
      }
      else
      {
        mbi->motion_type = MC_FIELD;
        dmc = dmcfield;
        vmc = dist2(oldref+(tsel?width:0)+(imint>>1)+(width<<1)*(jmint>>1),
                    mb,width<<1,imint&1,jmint&1,8);
        vmc+= dist2(oldref+(bsel?width:0)+(iminb>>1)+(width<<1)*(jminb>>1),
                    mb+width,width<<1,iminb&1,jminb&1,8);
      }
    }

    /* select between intra or non-intra coding:
     *
     * selection is based on intra block variance (var) vs.
     * prediction error variance (vmc)
     *
     * blocks with small prediction error are always coded non-intra
     * even if variance is smaller (is this reasonable?)
     */
    if (vmc>var && vmc>=9*256)
      mbi->mb_type = MB_INTRA;
    else
    {
      /* select between MC / No-MC
       *
       * use No-MC if var(No-MC) <= 1.25*var(MC)
       * (i.e slightly biased towards No-MC)
       *
       * blocks with small prediction error are always coded as No-MC
       * (requires no motion vectors, allows skipping)
       */
      v0 = dist2(oldref+i+width*j,mb,width,0,0,16);
      if (4*v0>5*vmc && v0>=9*256)
      {
        /* use MC */
        var = vmc;
        mbi->mb_type = MB_FORWARD;
        if (mbi->motion_type==MC_FRAME)
        {
          mbi->MV[0][0][0] = imin - (i<<1);
          mbi->MV[0][0][1] = jmin - (j<<1);
        }
        else if (mbi->motion_type==MC_DMV)
        {
          /* these are FRAME vectors */
          /* same parity vector */
          mbi->MV[0][0][0] = imindp - (i<<1);
          mbi->MV[0][0][1] = (jmindp<<1) - (j<<1);

          /* opposite parity vector */
          mbi->dmvector[0] = imindmv;
          mbi->dmvector[1] = jmindmv;
        }
        else
        {
          /* these are FRAME vectors */
          mbi->MV[0][0][0] = imint - (i<<1);
          mbi->MV[0][0][1] = (jmint<<1) - (j<<1);
          mbi->MV[1][0][0] = iminb - (i<<1);
          mbi->MV[1][0][1] = (jminb<<1) - (j<<1);
          mbi->mv_field_sel[0][0] = tsel;
          mbi->mv_field_sel[1][0] = bsel;
        }
      }
      else
      {
        /* No-MC */
        var = v0;
        mbi->mb_type = 0;
        mbi->motion_type = MC_FRAME;
        mbi->MV[0][0][0] = 0;
        mbi->MV[0][0][1] = 0;
      }
    }
  }
  else /* if (pict_type==B_TYPE) */
  {
    if (frame_pred_dct)
    {
      /* forward */
      dmcf = fullsearch(oldorg,oldref,mb,
                        width,i,j,sxf,syf,16,width,height,&iminf,&jminf);
      vmcf = dist2(oldref+(iminf>>1)+width*(jminf>>1),mb,
                   width,iminf&1,jminf&1,16);

      /* backward */
      dmcr = fullsearch(neworg,newref,mb,
                        width,i,j,sxb,syb,16,width,height,&iminr,&jminr);
      vmcr = dist2(newref+(iminr>>1)+width*(jminr>>1),mb,
                   width,iminr&1,jminr&1,16);

      /* interpolated (bidirectional) */
      vmci = bdist2(oldref+(iminf>>1)+width*(jminf>>1),
                    newref+(iminr>>1)+width*(jminr>>1),
                    mb,width,iminf&1,jminf&1,iminr&1,jminr&1,16);

      /* decisions */

      /* select between forward/backward/interpolated prediction:
       * use the one with smallest mean sqaured prediction error
       */
      if (vmcf<=vmcr && vmcf<=vmci)
      {
        vmc = vmcf;
        mbi->mb_type = MB_FORWARD;
      }
      else if (vmcr<=vmci)
      {
        vmc = vmcr;
        mbi->mb_type = MB_BACKWARD;
      }
      else
      {
        vmc = vmci;
        mbi->mb_type = MB_FORWARD|MB_BACKWARD;
      }

      mbi->motion_type = MC_FRAME;
    }
    else
    {
      /* forward prediction */
      frame_estimate(oldorg,oldref,mb,i,j,sxf,syf,
        &iminf,&jminf,&imintf,&jmintf,&iminbf,&jminbf,
        &dmcf,&dmcfieldf,&tself,&bself,imins,jmins);

      /* backward prediction */
      frame_estimate(neworg,newref,mb,i,j,sxb,syb,
        &iminr,&jminr,&imintr,&jmintr,&iminbr,&jminbr,
        &dmcr,&dmcfieldr,&tselr,&bselr,imins,jmins);

      /* calculate interpolated distance */
      /* frame */
      dmci = bdist1(oldref+(iminf>>1)+width*(jminf>>1),
                    newref+(iminr>>1)+width*(jminr>>1),
                    mb,width,iminf&1,jminf&1,iminr&1,jminr&1,16);

      /* top field */
      dmcfieldi = bdist1(
                    oldref+(imintf>>1)+(tself?width:0)+(width<<1)*(jmintf>>1),
                    newref+(imintr>>1)+(tselr?width:0)+(width<<1)*(jmintr>>1),
                    mb,width<<1,imintf&1,jmintf&1,imintr&1,jmintr&1,8);

      /* bottom field */
      dmcfieldi+= bdist1(
                    oldref+(iminbf>>1)+(bself?width:0)+(width<<1)*(jminbf>>1),
                    newref+(iminbr>>1)+(bselr?width:0)+(width<<1)*(jminbr>>1),
                    mb+width,width<<1,iminbf&1,jminbf&1,iminbr&1,jminbr&1,8);

      /* select prediction type of minimum distance from the
       * six candidates (field/frame * forward/backward/interpolated)
       */
      if (dmci<dmcfieldi && dmci<dmcf && dmci<dmcfieldf
          && dmci<dmcr && dmci<dmcfieldr)
      {
        /* frame, interpolated */
        mbi->mb_type = MB_FORWARD|MB_BACKWARD;
        mbi->motion_type = MC_FRAME;
        vmc = bdist2(oldref+(iminf>>1)+width*(jminf>>1),
                     newref+(iminr>>1)+width*(jminr>>1),
                     mb,width,iminf&1,jminf&1,iminr&1,jminr&1,16);
      }
      else if (dmcfieldi<dmcf && dmcfieldi<dmcfieldf
               && dmcfieldi<dmcr && dmcfieldi<dmcfieldr)
      {
        /* field, interpolated */
        mbi->mb_type = MB_FORWARD|MB_BACKWARD;
        mbi->motion_type = MC_FIELD;
        vmc = bdist2(oldref+(imintf>>1)+(tself?width:0)+(width<<1)*(jmintf>>1),
                     newref+(imintr>>1)+(tselr?width:0)+(width<<1)*(jmintr>>1),
                     mb,width<<1,imintf&1,jmintf&1,imintr&1,jmintr&1,8);
        vmc+= bdist2(oldref+(iminbf>>1)+(bself?width:0)+(width<<1)*(jminbf>>1),
                     newref+(iminbr>>1)+(bselr?width:0)+(width<<1)*(jminbr>>1),
                     mb+width,width<<1,iminbf&1,jminbf&1,iminbr&1,jminbr&1,8);
      }
      else if (dmcf<dmcfieldf && dmcf<dmcr && dmcf<dmcfieldr)
      {
        /* frame, forward */
        mbi->mb_type = MB_FORWARD;
        mbi->motion_type = MC_FRAME;
        vmc = dist2(oldref+(iminf>>1)+width*(jminf>>1),mb,
                    width,iminf&1,jminf&1,16);
      }
      else if (dmcfieldf<dmcr && dmcfieldf<dmcfieldr)
      {
        /* field, forward */
        mbi->mb_type = MB_FORWARD;
        mbi->motion_type = MC_FIELD;
        vmc = dist2(oldref+(tself?width:0)+(imintf>>1)+(width<<1)*(jmintf>>1),
                    mb,width<<1,imintf&1,jmintf&1,8);
        vmc+= dist2(oldref+(bself?width:0)+(iminbf>>1)+(width<<1)*(jminbf>>1),
                    mb+width,width<<1,iminbf&1,jminbf&1,8);
      }
      else if (dmcr<dmcfieldr)
      {
        /* frame, backward */
        mbi->mb_type = MB_BACKWARD;
        mbi->motion_type = MC_FRAME;
        vmc = dist2(newref+(iminr>>1)+width*(jminr>>1),mb,
                    width,iminr&1,jminr&1,16);
      }
      else
      {
        /* field, backward */
        mbi->mb_type = MB_BACKWARD;
        mbi->motion_type = MC_FIELD;
        vmc = dist2(newref+(tselr?width:0)+(imintr>>1)+(width<<1)*(jmintr>>1),
                    mb,width<<1,imintr&1,jmintr&1,8);
        vmc+= dist2(newref+(bselr?width:0)+(iminbr>>1)+(width<<1)*(jminbr>>1),
                    mb+width,width<<1,iminbr&1,jminbr&1,8);
      }
    }

    /* select between intra or non-intra coding:
     *
     * selection is based on intra block variance (var) vs.
     * prediction error variance (vmc)
     *
     * blocks with small prediction error are always coded non-intra
     * even if variance is smaller (is this reasonable?)
     */
    if (vmc>var && vmc>=9*256)
      mbi->mb_type = MB_INTRA;
    else
    {
      var = vmc;
      if (mbi->motion_type==MC_FRAME)
      {
        /* forward */
        mbi->MV[0][0][0] = iminf - (i<<1);
        mbi->MV[0][0][1] = jminf - (j<<1);
        /* backward */
        mbi->MV[0][1][0] = iminr - (i<<1);
        mbi->MV[0][1][1] = jminr - (j<<1);
      }
      else
      {
        /* these are FRAME vectors */
        /* forward */
        mbi->MV[0][0][0] = imintf - (i<<1);
        mbi->MV[0][0][1] = (jmintf<<1) - (j<<1);
        mbi->MV[1][0][0] = iminbf - (i<<1);
        mbi->MV[1][0][1] = (jminbf<<1) - (j<<1);
        mbi->mv_field_sel[0][0] = tself;
        mbi->mv_field_sel[1][0] = bself;
        /* backward */
        mbi->MV[0][1][0] = imintr - (i<<1);
        mbi->MV[0][1][1] = (jmintr<<1) - (j<<1);
        mbi->MV[1][1][0] = iminbr - (i<<1);
        mbi->MV[1][1][1] = (jminbr<<1) - (j<<1);
        mbi->mv_field_sel[0][1] = tselr;
        mbi->mv_field_sel[1][1] = bselr;
      }
    }
  }

  mbi->var = var;
}

/*
 * 场图像的运动估计
 *
 *oldorg：前向预测的原始参考图（供P图像和B图像使用）
 *neworg：后向预测的原始参考图（仅供B图像使用）
 *oldref：前向预测的重建图像（P图像和B图像）
 *newref：后向预测的重建图像（B图像）
 *cur：当前原始图像帧（由预测图像产生的）
 *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)
    {
      /* opposite parity field is in same frame */
      if (pict_struct==TOP_FIELD)
      {
        /* current is top field */
        botorg = cur + width;
        botref = curref + width;
      }
      else
      {
        /* current is bottom field */
        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)  /* generic condition which permits Dual Prime */
      dpfield_estimate(topref,botref,mb,i,j,imins,jmins,&imindmv,&jmindmv,
        &dmc_dp,&vmc_dp);

    /* select between dual prime, field and 16x8 prediction */
    if (M==1 && !ipflag && dmc_dp<dmc8 && dmc_dp<dmcfield)
    {
      /* Dual Prime prediction */
      mbi->motion_type = MC_DMV;
      dmc = dmc_dp;     /* L1 metric */
      vmc = vmc_dp;     /* we already calculated L2 error for Dual */

    }
    else if (dmc8<dmcfield)
    {
      /* 16x8 prediction */
      mbi->motion_type = MC_16X8;
      /* upper half block */
      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);