/* 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],