erc_do_p.c

可以用H.264编码解码器源码(c语言)

/*!
 *************************************************************************************
 * \file 
 *      erc_do_p.c
 *
 * \brief
 *      Inter (P) frame error concealment algorithms for decoder
 *
 *  \author
 *      - Viktor Varsa                     <[e-mail]>
 *      - Ye-Kui Wang                   <[e-mail]>
 *
 *************************************************************************************
 */

#include <stdlib.h>
#include <assert.h>
#include "mbuffer.h"
#include "global.h"
#include "memalloc.h"
#include "erc_do.h"
#include "image.h"

extern int erc_mvperMB;
struct img_par *erc_img;

// static function declarations
static int concealByCopy(frame *recfr, int currMBNum,
  objectBuffer_t *object_list, int32 picSizeX);
static int concealByTrial(frame *recfr, byte *predMB, 
                          int currMBNum, objectBuffer_t *object_list, int predBlocks[], 
                          int32 picSizeX, int32 picSizeY, int *yCondition);
static int edgeDistortion (int predBlocks[], int currYBlockNum, byte *predMB, 
                           byte *recY, int32 picSizeX, int32 regionSize);
static void copyBetweenFrames (frame *recfr, 
   int currYBlockNum, int32 picSizeX, int32 regionSize);
static void buildPredRegionYUV(struct img_par *img, int32 *mv, int x, int y, byte *predMB);
static void copyPredMB (int currYBlockNum, byte *predMB, frame *recfr, 
                        int32 picSizeX, int32 regionSize);

/*!
 ************************************************************************
 * \brief
 *      The main function for Inter (P) frame concealment.
 * \return
 *      0, if the concealment was not successful and simple concealment should be used
 *      1, otherwise (even if none of the blocks were concealed)
 * \param recfr
 *      Reconstructed frame buffer
 * \param object_list
 *      Motion info for all MBs in the frame
 * \param picSizeX
 *      Width of the frame in pixels
 * \param picSizeY
 *      Height of the frame in pixels
 * \param errorVar   
 *      Variables for error concealment
 ************************************************************************
 */
int ercConcealInterFrame(frame *recfr, objectBuffer_t *object_list, 
                         int32 picSizeX, int32 picSizeY, ercVariables_t *errorVar ) 
{
  int lastColumn = 0, lastRow = 0, predBlocks[8];
  int lastCorruptedRow = -1, firstCorruptedRow = -1, currRow = 0, 
    row, column, columnInd, areaHeight = 0, i = 0;
  byte *predMB;
  
  /* if concealment is on */
  if ( errorVar && errorVar->concealment ) 
  {
    /* if there are segments to be concealed */
    if ( errorVar->nOfCorruptedSegments ) 
    {
      
      predMB = (byte *) malloc(DEF_REGION_SIZE);
      if ( predMB == NULL ) no_mem_exit("ercConcealInterFrame: predMB");
      
      lastRow = (int) (picSizeY>>4);
      lastColumn = (int) (picSizeX>>4);
      
      for ( columnInd = 0; columnInd < lastColumn; columnInd ++) 
      {
        
        column = ((columnInd%2) ? (lastColumn - columnInd/2 -1) : (columnInd/2));
        
        for ( row = 0; row < lastRow; row++) 
        {
          
          if ( errorVar->yCondition[MBxy2YBlock(column, row, 0, picSizeX)] <= ERC_BLOCK_CORRUPTED ) 
          {                           // ERC_BLOCK_CORRUPTED (1) or ERC_BLOCK_EMPTY (0)
            firstCorruptedRow = row;
            /* find the last row which has corrupted blocks (in same continuous area) */
            for ( lastCorruptedRow = row+1; lastCorruptedRow < lastRow; lastCorruptedRow++) 
            {
              /* check blocks in the current column */
              if (errorVar->yCondition[MBxy2YBlock(column, lastCorruptedRow, 0, picSizeX)] > ERC_BLOCK_CORRUPTED) 
              {
                /* current one is already OK, so the last was the previous one */
                lastCorruptedRow --;
                break;
              }
            }
            if ( lastCorruptedRow >= lastRow ) 
            {
              /* correct only from above */
              lastCorruptedRow = lastRow-1;
              for ( currRow = firstCorruptedRow; currRow < lastRow; currRow++ ) 
              {
                
                ercCollect8PredBlocks (predBlocks, (currRow<<1), (column<<1), 
                  errorVar->yCondition, (lastRow<<1), (lastColumn<<1), 2, 0);      
                
                if(erc_mvperMB >= MVPERMB_THR)
                  concealByTrial(recfr, predMB, 
                    currRow*lastColumn+column, object_list, predBlocks, 
                    picSizeX, picSizeY,
                    errorVar->yCondition);
                else 
                  concealByCopy(recfr, currRow*lastColumn+column, 
                    object_list, picSizeX);
                
                ercMarkCurrMBConcealed (currRow*lastColumn+column, -1, picSizeX, errorVar);
              }
              row = lastRow;
            } 
            else if ( firstCorruptedRow == 0 ) 
            {
              /* correct only from below */
              for ( currRow = lastCorruptedRow; currRow >= 0; currRow-- ) 
              {
                
                ercCollect8PredBlocks (predBlocks, (currRow<<1), (column<<1), 
                  errorVar->yCondition, (lastRow<<1), (lastColumn<<1), 2, 0);      
                
                if(erc_mvperMB >= MVPERMB_THR)
                  concealByTrial(recfr, predMB, 
                    currRow*lastColumn+column, object_list, predBlocks, 
                    picSizeX, picSizeY,
                    errorVar->yCondition);
                else 
                  concealByCopy(recfr, currRow*lastColumn+column, 
                    object_list, picSizeX);
                
                ercMarkCurrMBConcealed (currRow*lastColumn+column, -1, picSizeX, errorVar);
              }
              
              row = lastCorruptedRow+1;
            }
            else 
            {
              /* correct bi-directionally */
              
              row = lastCorruptedRow+1;
              
              areaHeight = lastCorruptedRow-firstCorruptedRow+1;
              
              /* 
              *  Conceal the corrupted area switching between the up and the bottom rows 
              */
              for ( i = 0; i < areaHeight; i++) 
              {
                if ( i % 2 ) 
                {
                  currRow = lastCorruptedRow;
                  lastCorruptedRow --;
                }
                else 
                {
                  currRow = firstCorruptedRow;
                  firstCorruptedRow ++; 
                }
                
                ercCollect8PredBlocks (predBlocks, (currRow<<1), (column<<1), 
                  errorVar->yCondition, (lastRow<<1), (lastColumn<<1), 2, 0);      
                
                if(erc_mvperMB >= MVPERMB_THR)
                  concealByTrial(recfr, predMB, 
                    currRow*lastColumn+column, object_list, predBlocks, 
                    picSizeX, picSizeY,
                    errorVar->yCondition);
                else
                  concealByCopy(recfr, currRow*lastColumn+column, 
                    object_list, picSizeX);
                
                ercMarkCurrMBConcealed (currRow*lastColumn+column, -1, picSizeX, errorVar);
                
              }
            }
            lastCorruptedRow = -1;
            firstCorruptedRow = -1;
          }
        }
      }
    
      free(predMB);
    }
    return 1;
  }
  else
    return 0;
}

/*!
 ************************************************************************
 * \brief
 *      It conceals a given MB by simply copying the pixel area from the reference image 
 *      that is at the same location as the macroblock in the current image. This correcponds 
 *      to COPY MBs. 
 * \return
 *      Always zero (0).
 * \param recfr
 *      Reconstructed frame buffer
 * \param currMBNum
 *      current MB index
 * \param object_list
 *      Motion info for all MBs in the frame
 * \param picSizeX
 *      Width of the frame in pixels
 ************************************************************************
 */
static int concealByCopy(frame *recfr, int currMBNum,
  objectBuffer_t *object_list, int32 picSizeX)
{
  objectBuffer_t *currRegion;
   
  currRegion = object_list+(currMBNum<<2);
  currRegion->regionMode = REGMODE_INTER_COPY;
   
  currRegion->xMin = (xPosMB(currMBNum,picSizeX)<<4);
  currRegion->yMin = (yPosMB(currMBNum,picSizeX)<<4);
   
  copyBetweenFrames (recfr, MBNum2YBlock(currMBNum,0,picSizeX), picSizeX, 16);
   
  return 0;
}

/*!
 ************************************************************************
 * \brief
 *      Copies the co-located pixel values from the reference to the current frame. 
 *      Used by concealByCopy
 * \param recfr
 *      Reconstructed frame buffer
 * \param currYBlockNum
 *      index of the block (8x8) in the Y plane
 * \param picSizeX
 *      Width of the frame in pixels
 * \param regionSize      
 *      can be 16 or 8 to tell the dimension of the region to copy
 ************************************************************************
 */
static void copyBetweenFrames (frame *recfr, 
   int currYBlockNum, int32 picSizeX, int32 regionSize)
{
  int j, k, location, xmin, ymin;
   
  /* set the position of the region to be copied */
  xmin = (xPosYBlock(currYBlockNum,picSizeX)<<3);
  ymin = (yPosYBlock(currYBlockNum,picSizeX)<<3);
   
  for (j = ymin; j < ymin + regionSize; j++)
    for (k = xmin; k < xmin + regionSize; k++)
    {
      location = j * picSizeX + k; 
      recfr->yptr[location] = dec_picture->imgY[j][k];
    }
     
    for (j = ymin / 2; j < (ymin + regionSize) / 2; j++)
      for (k = xmin / 2; k < (xmin + regionSize) / 2; k++)
      {
        location = j * picSizeX / 2 + k;
        recfr->uptr[location] = dec_picture->imgUV[0][j][k];
        recfr->vptr[location] = dec_picture->imgUV[1][j][k];
      }                                
}

/*!
 ************************************************************************
 * \brief
 *      It conceals a given MB by using the motion vectors of one reliable neighbor. That MV of a 
 *      neighbor is selected wich gives the lowest pixel difference at the edges of the MB 
 *      (see function edgeDistortion). This corresponds to a spatial smoothness criteria.
 * \return
 *      Always zero (0).
 * \param recfr
 *      Reconstructed frame buffer
 * \param predMB
 *      memory area for storing temporary pixel values for a macroblock
 *      the Y,U,V planes are concatenated y = predMB, u = predMB+256, v = predMB+320
 * \param currMBNum
 *      current MB index
 * \param object_list
 *      array of region structures storing region mode and mv for each region
 * \param predBlocks
 *      status array of the neighboring blocks (if they are OK, concealed or lost)
 * \param picSizeX
 *      Width of the frame in pixels
 * \param picSizeY
 *      Height of the frame in pixels
 * \param yCondition
 *      array for conditions of Y blocks from ercVariables_t
 ************************************************************************
 */
static int concealByTrial(frame *recfr, byte *predMB, 
                          int currMBNum, objectBuffer_t *object_list, int predBlocks[], 
                          int32 picSizeX, int32 picSizeY, int *yCondition)
{
  int predMBNum = 0, numMBPerLine,
      compSplit1 = 0, compSplit2 = 0, compLeft = 1, comp = 0, compPred, order = 1,
      fInterNeighborExists, numIntraNeighbours,
      fZeroMotionChecked, predSplitted = 0,
      threshold = ERC_BLOCK_OK,
      minDist, currDist, i, k, bestDir;
  int32 regionSize;
  objectBuffer_t *currRegion;
  int32 mvBest[3] , mvPred[3], *mvptr;
  
  numMBPerLine = (int) (picSizeX>>4);
  
  comp = 0;
  regionSize = 16;
  
  do 
  { /* 4 blocks loop */
    
    currRegion = object_list+(currMBNum<<2)+comp;
    
    /* set the position of the region to be concealed */
    
    currRegion->xMin = (xPosYBlock(MBNum2YBlock(currMBNum,comp,picSizeX),picSizeX)<<3);
    currRegion->yMin = (yPosYBlock(MBNum2YBlock(currMBNum,comp,picSizeX),picSizeX)<<3);
    
    do 
    { /* reliability loop */
      
      minDist = 0; 
      fInterNeighborExists = 0; 
      numIntraNeighbours = 0; 
      fZeroMotionChecked = 0;
      
      /* loop the 4 neighbours */
      for (i = 4; i < 8; i++) 
      {
        
        /* if reliable, try it */
        if (predBlocks[i] >= threshold) 
        {
          switch (i) 
          {
          case 4:
            predMBNum = currMBNum-numMBPerLine;
            compSplit1 = 2;
            compSplit2 = 3;
            break;
              
          case 5:
            predMBNum = currMBNum-1;
            compSplit1 = 1;
            compSplit2 = 3;
            break;
              
          case 6:
            predMBNum = currMBNum+numMBPerLine;
            compSplit1 = 0;
            compSplit2 = 1;
            break;
              
          case 7:
            predMBNum = currMBNum+1;
            compSplit1 = 0;
            compSplit2 = 2;
            break;
          }
          
          /* try the concealment with the Motion Info of the current neighbour
          only try if the neighbour is not Intra */
          if (isBlock(object_list,predMBNum,compSplit1,INTRA) || 
            isBlock(object_list,predMBNum,compSplit2,INTRA))
          {            
            numIntraNeighbours++;
          } 
          else 
          {
            /* if neighbour MB is splitted, try both neighbour blocks */
            for (predSplitted = isSplitted(object_list, predMBNum), 
              compPred = compSplit1;
              predSplitted >= 0;
              compPred = compSplit2,
              predSplitted -= ((compSplit1 == compSplit2) ? 2 : 1)) 
            {