recon.c

DirectFB-1.0.1可用于linux的嵌入式GUI

/* 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 "global.h"

/* private prototypes */
static void form_prediction (MPEG2_Decoder *dec, 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 (MPEG2_Decoder *dec, 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
MPEG2_form_predictions(MPEG2_Decoder *dec,
                       int bx, int by,
                       int macroblock_type,
                       int motion_type,
                       int PMV[2][2][2], int motion_vertical_field_select[2][2], int 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) 
         || (dec->picture_coding_type==P_TYPE)) {
          if (dec->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(dec, dec->forward_reference_frame,0,dec->current_frame,0,
                                         dec->Coded_Picture_Width,dec->Coded_Picture_Width<<1,16,8,bx,by,
                                         PMV[0][0][0],PMV[0][0][1],stwtop);

                    if (stwbot<2)
                         form_prediction(dec, dec->forward_reference_frame,1,dec->current_frame,1,
                                         dec->Coded_Picture_Width,dec->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(dec, dec->forward_reference_frame,motion_vertical_field_select[0][0],
                                         dec->current_frame,0,dec->Coded_Picture_Width<<1,dec->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(dec, dec->forward_reference_frame,motion_vertical_field_select[1][0],
                                         dec->current_frame,1,dec->Coded_Picture_Width<<1,dec->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 */
                    MPEG2_Dual_Prime_Arithmetic(dec, DMV,dmvector,PMV[0][0][0],PMV[0][0][1]>>1);

                    if (stwtop<2) {
                         /* predict top field from top field */
                         form_prediction(dec, dec->forward_reference_frame,0,dec->current_frame,0,
                                         dec->Coded_Picture_Width<<1,dec->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(dec, dec->forward_reference_frame,1,dec->current_frame,0,
                                         dec->Coded_Picture_Width<<1,dec->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(dec, dec->forward_reference_frame,1,dec->current_frame,1,
                                         dec->Coded_Picture_Width<<1,dec->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(dec, dec->forward_reference_frame,0,dec->current_frame,1,
                                         dec->Coded_Picture_Width<<1,dec->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 = (dec->picture_structure==BOTTOM_FIELD);

               /* determine which frame to use for prediction */
               if ((dec->picture_coding_type==P_TYPE) && dec->Second_Field
                   && (currentfield!=motion_vertical_field_select[0][0]))
                    predframe = dec->backward_reference_frame; /* same frame */
               else
                    predframe = dec->forward_reference_frame; /* previous frame */

               if ((motion_type==MC_FIELD)
                   || !(macroblock_type & MACROBLOCK_MOTION_FORWARD)) {
                    /* field-based prediction */
                    if (stwtop<2)
                         form_prediction(dec, predframe,motion_vertical_field_select[0][0],dec->current_frame,0,
                                         dec->Coded_Picture_Width<<1,dec->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(dec, predframe,motion_vertical_field_select[0][0],dec->current_frame,0,
                                         dec->Coded_Picture_Width<<1,dec->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 ((dec->picture_coding_type==P_TYPE) && dec->Second_Field
                             && (currentfield!=motion_vertical_field_select[1][0]))
                              predframe = dec->backward_reference_frame; /* same frame */
                         else
                              predframe = dec->forward_reference_frame; /* previous frame */

                         form_prediction(dec, predframe,motion_vertical_field_select[1][0],dec->current_frame,0,
                                         dec->Coded_Picture_Width<<1,dec->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 (dec->Second_Field)
                         predframe = dec->backward_reference_frame; /* same frame */
                    else
                         predframe = dec->forward_reference_frame; /* previous frame */

                    /* calculate derived motion vectors */
                    MPEG2_Dual_Prime_Arithmetic(dec, DMV,dmvector,PMV[0][0][0],PMV[0][0][1]);

                    /* predict from field of same parity */
                    form_prediction(dec, dec->forward_reference_frame,currentfield,dec->current_frame,0,
                                    dec->Coded_Picture_Width<<1,dec->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(dec, predframe,!currentfield,dec->current_frame,0,
                                    dec->Coded_Picture_Width<<1,dec->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 (dec->picture_structure==FRAME_PICTURE) {
               if (motion_type==MC_FRAME) {
                    /* frame-based prediction */
                    if (stwtop<2)
                         form_prediction(dec, dec->backward_reference_frame,0,dec->current_frame,0,
                                         dec->Coded_Picture_Width,dec->Coded_Picture_Width<<1,16,8,bx,by,
                                         PMV[0][1][0],PMV[0][1][1],stwtop);

                    if (stwbot<2)
                         form_prediction(dec, dec->backward_reference_frame,1,dec->current_frame,1,
                                         dec->Coded_Picture_Width,dec->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(dec, dec->backward_reference_frame,motion_vertical_field_select[0][1],
                                         dec->current_frame,0,dec->Coded_Picture_Width<<1,dec->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(dec, dec->backward_reference_frame,motion_vertical_field_select[1][1],
                                         dec->current_frame,1,dec->Coded_Picture_Width<<1,dec->Coded_Picture_Width<<1,16,8,
                                         bx,by>>1,PMV[1][1][0],PMV[1][1][1]>>1,stwbot);
               }
          }