/* Predict.c, motion compensation routines                                    *//* 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"/* private prototypes */static void form_prediction _ANSI_ARGS_((unsigned char *src[], int sfield,  unsigned char *dst[], int dfield,  int lx, int lx2, int w, int h, int x, int y, int dx, int dy,  int average_flag));static void form_component_prediction _ANSI_ARGS_((unsigned char *src, unsigned char *dst,  int lx, int lx2, int w, int h, int x, int y, int dx, int dy, int average_flag));void form_predictions(bx,by,macroblock_type,motion_type,PMV,motion_vertical_field_select,dmvector,stwtype)int bx, by;int macroblock_type;int motion_type;int PMV[2][2][2], motion_vertical_field_select[2][2], dmvector[2];int stwtype;{  int currentfield;  unsigned char **predframe;  int DMV[2][2];  int stwtop, stwbot;  stwtop = stwtype%3; /* 0:temporal, 1:(spat+temp)/2, 2:spatial */  stwbot = stwtype/3;  if ((macroblock_type & MACROBLOCK_MOTION_FORWARD)    || (picture_coding_type==P_TYPE))  {    if (picture_structure==FRAME_PICTURE)    {      if ((motion_type==MC_FRAME)         || !(macroblock_type & MACROBLOCK_MOTION_FORWARD))      {        /* frame-based prediction (broken into top and bottom halves             for spatial scalability prediction purposes) */        if (stwtop<2)          form_prediction(forward_reference_frame,0,current_frame,0,            Coded_Picture_Width,Coded_Picture_Width<<1,16,8,bx,by,            PMV[0][0][0],PMV[0][0][1],stwtop);        if (stwbot<2)          form_prediction(forward_reference_frame,1,current_frame,1,            Coded_Picture_Width,Coded_Picture_Width<<1,16,8,bx,by,            PMV[0][0][0],PMV[0][0][1],stwbot);      }      else if (motion_type==MC_FIELD) /* field-based prediction */      {        /* top field prediction */        if (stwtop<2)          form_prediction(forward_reference_frame,motion_vertical_field_select[0][0],            current_frame,0,Coded_Picture_Width<<1,Coded_Picture_Width<<1,16,8,            bx,by>>1,PMV[0][0][0],PMV[0][0][1]>>1,stwtop);        /* bottom field prediction */        if (stwbot<2)          form_prediction(forward_reference_frame,motion_vertical_field_select[1][0],            current_frame,1,Coded_Picture_Width<<1,Coded_Picture_Width<<1,16,8,            bx,by>>1,PMV[1][0][0],PMV[1][0][1]>>1,stwbot);      }      else if (motion_type==MC_DMV) /* dual prime prediction */      {        /* calculate derived motion vectors */        Dual_Prime_Arithmetic(DMV,dmvector,PMV[0][0][0],PMV[0][0][1]>>1);        if (stwtop<2)        {          /* predict top field from top field */          form_prediction(forward_reference_frame,0,current_frame,0,            Coded_Picture_Width<<1,Coded_Picture_Width<<1,16,8,bx,by>>1,            PMV[0][0][0],PMV[0][0][1]>>1,0);          /* predict and add to top field from bottom field */          form_prediction(forward_reference_frame,1,current_frame,0,            Coded_Picture_Width<<1,Coded_Picture_Width<<1,16,8,bx,by>>1,            DMV[0][0],DMV[0][1],1);        }        if (stwbot<2)        {          /* predict bottom field from bottom field */          form_prediction(forward_reference_frame,1,current_frame,1,            Coded_Picture_Width<<1,Coded_Picture_Width<<1,16,8,bx,by>>1,            PMV[0][0][0],PMV[0][0][1]>>1,0);          /* predict and add to bottom field from top field */          form_prediction(forward_reference_frame,0,current_frame,1,            Coded_Picture_Width<<1,Coded_Picture_Width<<1,16,8,bx,by>>1,            DMV[1][0],DMV[1][1],1);        }      }      else        /* invalid motion_type */        printf("invalid motion_type\n");    }    else /* TOP_FIELD or BOTTOM_FIELD */    {      /* field picture */      currentfield = (picture_structure==BOTTOM_FIELD);      /* determine which frame to use for prediction */      if ((picture_coding_type==P_TYPE) && Second_Field         && (currentfield!=motion_vertical_field_select[0][0]))        predframe = backward_reference_frame; /* same frame */      else        predframe = forward_reference_frame; /* previous frame */      if ((motion_type==MC_FIELD)        || !(macroblock_type & MACROBLOCK_MOTION_FORWARD))      {        /* field-based prediction */        if (stwtop<2)          form_prediction(predframe,motion_vertical_field_select[0][0],current_frame,0,            Coded_Picture_Width<<1,Coded_Picture_Width<<1,16,16,bx,by,            PMV[0][0][0],PMV[0][0][1],stwtop);      }      else if (motion_type==MC_16X8)      {        if (stwtop<2)        {          form_prediction(predframe,motion_vertical_field_select[0][0],current_frame,0,            Coded_Picture_Width<<1,Coded_Picture_Width<<1,16,8,bx,by,            PMV[0][0][0],PMV[0][0][1],stwtop);          /* determine which frame to use for lower half prediction */          if ((picture_coding_type==P_TYPE) && Second_Field             && (currentfield!=motion_vertical_field_select[1][0]))            predframe = backward_reference_frame; /* same frame */          else            predframe = forward_reference_frame; /* previous frame */          form_prediction(predframe,motion_vertical_field_select[1][0],current_frame,0,            Coded_Picture_Width<<1,Coded_Picture_Width<<1,16,8,bx,by+8,            PMV[1][0][0],PMV[1][0][1],stwtop);        }      }      else if (motion_type==MC_DMV) /* dual prime prediction */      {        if (Second_Field)          predframe = backward_reference_frame; /* same frame */        else          predframe = forward_reference_frame; /* previous frame */        /* calculate derived motion vectors */        Dual_Prime_Arithmetic(DMV,dmvector,PMV[0][0][0],PMV[0][0][1]);        /* predict from field of same parity */        form_prediction(forward_reference_frame,currentfield,current_frame,0,          Coded_Picture_Width<<1,Coded_Picture_Width<<1,16,16,bx,by,          PMV[0][0][0],PMV[0][0][1],0);        /* predict from field of opposite parity */        form_prediction(predframe,!currentfield,current_frame,0,          Coded_Picture_Width<<1,Coded_Picture_Width<<1,16,16,bx,by,          DMV[0][0],DMV[0][1],1);      }      else        /* invalid motion_type */        printf("invalid motion_type\n");    }    stwtop = stwbot = 1;  }  if (macroblock_type & MACROBLOCK_MOTION_BACKWARD)  {    if (picture_structure==FRAME_PICTURE)    {      if (motion_type==MC_FRAME)      {        /* frame-based prediction */        if (stwtop<2)          form_prediction(backward_reference_frame,0,current_frame,0,            Coded_Picture_Width,Coded_Picture_Width<<1,16,8,bx,by,            PMV[0][1][0],PMV[0][1][1],stwtop);        if (stwbot<2)          form_prediction(backward_reference_frame,1,current_frame,1,            Coded_Picture_Width,Coded_Picture_Width<<1,16,8,bx,by,            PMV[0][1][0],PMV[0][1][1],stwbot);      }      else /* field-based prediction */      {        /* top field prediction */        if (stwtop<2)          form_prediction(backward_reference_frame,motion_vertical_field_select[0][1],            current_frame,0,Coded_Picture_Width<<1,Coded_Picture_Width<<1,16,8,            bx,by>>1,PMV[0][1][0],PMV[0][1][1]>>1,stwtop);        /* bottom field prediction */        if (stwbot<2)          form_prediction(backward_reference_frame,motion_vertical_field_select[1][1],            current_frame,1,Coded_Picture_Width<<1,Coded_Picture_Width<<1,16,8,            bx,by>>1,PMV[1][1][0],PMV[1][1][1]>>1,stwbot);      }    }    else /* TOP_FIELD or BOTTOM_FIELD */    {      /* field picture */      if (motion_type==MC_FIELD)      {        /* field-based prediction */        form_prediction(backward_reference_frame,motion_vertical_field_select[0][1],