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/*!

 *************************************************************************************

 * \file

 *      erc_do_i.c

 *

 * \brief

 *      Intra (I) frame error concealment algorithms for decoder

 *

 *  \author

 *      - Ari Hourunranta              <ari.hourunranta@nokia.com>

 *      - Viktor Varsa                 <viktor.varsa@nokia.com>

 *      - Ye-Kui Wang                  <wyk@ieee.org>

 *

 *************************************************************************************

 */

#include <stdlib.h>

#include "global.h"

#include "erc_do.h"

static void concealBlocks( int lastColumn, int lastRow, int comp, frame *recfr, int picSizeX, int *condition );

static void pixMeanInterpolateBlock( imgpel *src[], imgpel *block, int blockSize, int frameWidth );

/*!

 ************************************************************************

 * \brief

 *      The main function for Intra frame concealment.

 *      Calls "concealBlocks" for each color component (Y,U,V) separately

 * \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 picSizeX

 *      Width of the frame in pixels

 * \param picSizeY

 *      Height of the frame in pixels

 * \param errorVar

 *      Variables for error concealment

 ************************************************************************

 */

int ercConcealIntraFrame( frame *recfr, int picSizeX, int picSizeY, ercVariables_t *errorVar )

{

  int lastColumn = 0, lastRow = 0;

  // if concealment is on

  if ( errorVar && errorVar->concealment )

  {

    // if there are segments to be concealed

    if ( errorVar->nOfCorruptedSegments )

    {

      // Y

      lastRow = (int) (picSizeY>>3);

      lastColumn = (int) (picSizeX>>3);

      concealBlocks( lastColumn, lastRow, 0, recfr, picSizeX, errorVar->yCondition );

      // U (dimensions halved compared to Y)

      lastRow = (int) (picSizeY>>4);

      lastColumn = (int) (picSizeX>>4);

      concealBlocks( lastColumn, lastRow, 1, recfr, picSizeX, errorVar->uCondition );

      // V ( dimensions equal to U )

      concealBlocks( lastColumn, lastRow, 2, recfr, picSizeX, errorVar->vCondition );

    }

    return 1;

  }

  else

    return 0;

}

/*!

 ************************************************************************

 * \brief

 *      Conceals the MB at position (row, column) using pixels from predBlocks[]

 *      using pixMeanInterpolateBlock()

 * \param currFrame

 *      current frame

 * \param row

 *      y coordinate in blocks

 * \param column

 *      x coordinate in blocks

 * \param predBlocks[]

 *      list of neighboring source blocks (numbering 0 to 7, 1 means: use the neighbor)

 * \param frameWidth

 *      width of frame in pixels

 * \param mbWidthInBlocks

 *      2 for Y, 1 for U/V components

 ************************************************************************

 */

void ercPixConcealIMB(imgpel *currFrame, int row, int column, int predBlocks[], int frameWidth, int mbWidthInBlocks)

{

   imgpel *src[8]={NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL};

   imgpel *currBlock = NULL;

   // collect the reliable neighboring blocks

   if (predBlocks[0])

      src[0] = currFrame + (row-mbWidthInBlocks)*frameWidth*8 + (column+mbWidthInBlocks)*8;

   if (predBlocks[1])

      src[1] = currFrame + (row-mbWidthInBlocks)*frameWidth*8 + (column-mbWidthInBlocks)*8;

   if (predBlocks[2])

      src[2] = currFrame + (row+mbWidthInBlocks)*frameWidth*8 + (column-mbWidthInBlocks)*8;

   if (predBlocks[3])

      src[3] = currFrame + (row+mbWidthInBlocks)*frameWidth*8 + (column+mbWidthInBlocks)*8;

   if (predBlocks[4])

      src[4] = currFrame + (row-mbWidthInBlocks)*frameWidth*8 + column*8;

   if (predBlocks[5])

      src[5] = currFrame + row*frameWidth*8 + (column-mbWidthInBlocks)*8;

   if (predBlocks[6])

      src[6] = currFrame + (row+mbWidthInBlocks)*frameWidth*8 + column*8;

   if (predBlocks[7])

      src[7] = currFrame + row*frameWidth*8 + (column+mbWidthInBlocks)*8;

   currBlock = currFrame + row*frameWidth*8 + column*8;

   pixMeanInterpolateBlock( src, currBlock, mbWidthInBlocks*8, frameWidth );

}

/*!

 ************************************************************************

 * \brief

 *      This function checks the neighbors of a Macroblock for usability in

 *      concealment. First the OK macroblocks are marked, and if there is not

 *      enough of them, then the CONCEALED ones as well.

 *      A "1" in the the output array means reliable, a "0" non reliable MB.

 *      The block order in "predBlocks":

 *              1 4 0

 *              5 x 7

 *              2 6 3

 *      i.e., corners first.

 * \return

 *      Number of useable neighbor macroblocks for concealment.

 * \param predBlocks[]

 *      Array for indicating the valid neighbor blocks

 * \param currRow

 *      Current block row in the frame

 * \param currColumn

 *      Current block column in the frame

 * \param condition

 *      The block condition (ok, lost) table

 * \param maxRow

 *      Number of block rows in the frame

 * \param maxColumn

 *      Number of block columns in the frame

 * \param step

 *      Number of blocks belonging to a MB, when counting

 *      in vertical/horizontal direction. (Y:2 U,V:1)

 * \param fNoCornerNeigh

 *      No corner neighbors are considered

 ************************************************************************

 */

int ercCollect8PredBlocks( int predBlocks[], int currRow, int currColumn, int *condition,

                           int maxRow, int maxColumn, int step, byte fNoCornerNeigh )

{

  int srcCounter  = 0;

  int srcCountMin = (fNoCornerNeigh ? 2 : 4);

  int threshold   = ERC_BLOCK_OK;

  memset( predBlocks, 0, 8*sizeof(int) );

  // collect the reliable neighboring blocks

  do

  {

    srcCounter = 0;

    // top

    if (currRow > 0 && condition[ (currRow-1)*maxColumn + currColumn ] >= threshold )

    {                           //ERC_BLOCK_OK (3) or ERC_BLOCK_CONCEALED (2)

      predBlocks[4] = condition[ (currRow-1)*maxColumn + currColumn ];

      srcCounter++;

    }

    // bottom

    if ( currRow < (maxRow-step) && condition[ (currRow+step)*maxColumn + currColumn ] >= threshold )

    {

      predBlocks[6] = condition[ (currRow+step)*maxColumn + currColumn ];

      srcCounter++;

    }

    if ( currColumn > 0 )

    {

      // left

      if ( condition[ currRow*maxColumn + currColumn - 1 ] >= threshold )

      {

        predBlocks[5] = condition[ currRow*maxColumn + currColumn - 1 ];

        srcCounter++;

      }

      if ( !fNoCornerNeigh )

      {

        // top-left

        if ( currRow > 0 && condition[ (currRow-1)*maxColumn + currColumn - 1 ] >= threshold )

        {

          predBlocks[1] = condition[ (currRow-1)*maxColumn + currColumn - 1 ];

          srcCounter++;

        }

        // bottom-left

        if ( currRow < (maxRow-step) && condition[ (currRow+step)*maxColumn + currColumn - 1 ] >= threshold )

        {

          predBlocks[2] = condition[ (currRow+step)*maxColumn + currColumn - 1 ];

          srcCounter++;

        }

      }

    }

    if ( currColumn < (maxColumn-step) )

    {

      // right

      if ( condition[ currRow*maxColumn+currColumn + step ] >= threshold )

      {

        predBlocks[7] = condition[ currRow*maxColumn+currColumn + step ];

        srcCounter++;

      }

      if ( !fNoCornerNeigh )

      {

        // top-right

        if ( currRow > 0 && condition[ (currRow-1)*maxColumn + currColumn + step ] >= threshold )

        {

          predBlocks[0] = condition[ (currRow-1)*maxColumn + currColumn + step ];

          srcCounter++;

        }

        // bottom-right

        if ( currRow < (maxRow-step) && condition[ (currRow+step)*maxColumn + currColumn + step ] >= threshold )

        {

          predBlocks[3] = condition[ (currRow+step)*maxColumn + currColumn + step ];

          srcCounter++;

        }

      }

    }

    // prepare for the next round

    threshold--;

    if (threshold < ERC_BLOCK_CONCEALED)

      break;

  } while ( srcCounter < srcCountMin);

  return srcCounter;

}

/*!

 ************************************************************************

 * \brief

 *      collects prediction blocks only from the current column

 * \return

 *      Number of usable neighbour Macroblocks for concealment.

 * \param predBlocks[]

 *      Array for indicating the valid neighbor blocks

 * \param currRow

 *      Current block row in the frame

 * \param currColumn

 *      Current block column in the frame

 * \param condition

 *      The block condition (ok, lost) table

 * \param maxRow

 *      Number of block rows in the frame

 * \param maxColumn

 *      Number of block columns in the frame

 * \param step

 *      Number of blocks belonging to a MB, when counting

 *      in vertical/horizontal direction. (Y:2 U,V:1)

 ************************************************************************

 */

int ercCollectColumnBlocks( int predBlocks[], int currRow, int currColumn, int *condition, int maxRow, int maxColumn, int step )

{

  int srcCounter = 0, threshold = ERC_BLOCK_CORRUPTED;

  memset( predBlocks, 0, 8*sizeof(int) );

  // in this case, row > 0 and row < 17

  if ( condition[ (currRow-1)*maxColumn + currColumn ] > threshold )

  {

    predBlocks[4] = 1;

    srcCounter++;

  }

  if ( condition[ (currRow+step)*maxColumn + currColumn ] > threshold )

  {

    predBlocks[6] = 1;

    srcCounter++;

  }

  return srcCounter;

}

/*!

 ************************************************************************

 * \brief

 *      Core for the Intra blocks concealment.

 *      It is called for each color component (Y,U,V) separately

 *      Finds the corrupted blocks and calls pixel interpolation functions

 *      to correct them, one block at a time.

 *      Scanning is done vertically and each corrupted column is corrected

 *      bi-directionally, i.e., first block, last block, first block+1, last block -1 ...

 * \param lastColumn

 *      Number of block columns in the frame

 * \param lastRow

 *      Number of block rows in the frame

 * \param comp

 *      color component

 * \param recfr

 *      Reconstructed frame buffer

 * \param picSizeX

 *      Width of the frame in pixels

 * \param condition

 *      The block condition (ok, lost) table

 ************************************************************************

 */

static void concealBlocks( int lastColumn, int lastRow, int comp, frame *recfr, int picSizeX, int *condition )

{

  int row, column, srcCounter = 0,  thr = ERC_BLOCK_CORRUPTED,

      lastCorruptedRow = -1, firstCorruptedRow = -1, currRow = 0,

      areaHeight = 0, i = 0, smoothColumn = 0;

  int predBlocks[8], step = 1;

  // in the Y component do the concealment MB-wise (not block-wise):

  // this is useful if only whole MBs can be damaged or lost

  if ( comp == 0 )

    step = 2;

  else

    step = 1;

  for ( column = 0; column < lastColumn; column += step )

  {

    for ( row = 0; row < lastRow; row += step )

    {

      if ( condition[row*lastColumn+column] <= thr )

      {

        firstCorruptedRow = row;

        // find the last row which has corrupted blocks (in same continuous area)

        for ( lastCorruptedRow = row+step; lastCorruptedRow < lastRow; lastCorruptedRow += step )

        {

          // check blocks in the current column

          if ( condition[ lastCorruptedRow*lastColumn + column ] > thr )

          {

            // current one is already OK, so the last was the previous one

            lastCorruptedRow -= step;

            break;

          }

        }

        if ( lastCorruptedRow >= lastRow )

        {

          // correct only from above

          lastCorruptedRow = lastRow-step;

          for ( currRow = firstCorruptedRow; currRow < lastRow; currRow += step )

          {

            srcCounter = ercCollect8PredBlocks( predBlocks, currRow, column, condition, lastRow, lastColumn, step, 1 );

            switch( comp )

            {

            case 0 :

              ercPixConcealIMB( recfr->yptr, currRow, column, predBlocks, picSizeX, 2 );

              break;

            case 1 :

              ercPixConcealIMB( recfr->uptr, currRow, column, predBlocks, (picSizeX>>1), 1 );

              break;

            case 2 :

              ercPixConcealIMB( recfr->vptr, currRow, column, predBlocks, (picSizeX>>1), 1 );

              break;

            }

            if ( comp == 0 )

            {

              condition[ currRow*lastColumn+column] = ERC_BLOCK_CONCEALED;

              condition[ currRow*lastColumn+column + 1] = ERC_BLOCK_CONCEALED;

              condition[ currRow*lastColumn+column + lastColumn] = ERC_BLOCK_CONCEALED;

              condition[ currRow*lastColumn+column + lastColumn + 1] = ERC_BLOCK_CONCEALED;

            }

            else

            {

              condition[ currRow*lastColumn+column] = ERC_BLOCK_CONCEALED;

            }

          }

          row = lastRow;

        }

        else if ( firstCorruptedRow == 0 )

        {

          // correct only from below

          for ( currRow = lastCorruptedRow; currRow >= 0; currRow -= step )

          {

            srcCounter = ercCollect8PredBlocks( predBlocks, currRow, column, condition, lastRow, lastColumn, step, 1 );

            switch( comp )

            {

            case 0 :

              ercPixConcealIMB( recfr->yptr, currRow, column, predBlocks, picSizeX, 2 );

              break;

            case 1 :

              ercPixConcealIMB( recfr->uptr, currRow, column, predBlocks, (picSizeX>>1), 1 );

              break;

            case 2 :

              ercPixConcealIMB( recfr->vptr, currRow, column, predBlocks, (picSizeX>>1), 1 );

              break;

            }

            if ( comp == 0 )

            {

              condition[ currRow*lastColumn+column] = ERC_BLOCK_CONCEALED;

              condition[ currRow*lastColumn+column + 1] = ERC_BLOCK_CONCEALED;

              condition[ currRow*lastColumn+column + lastColumn] = ERC_BLOCK_CONCEALED;

              condition[ currRow*lastColumn+column + lastColumn + 1] = ERC_BLOCK_CONCEALED;

            }

            else

            {

              condition[ currRow*lastColumn+column] = ERC_BLOCK_CONCEALED;

            }

          }

          row = lastCorruptedRow+step;

        }

        else

        {

          // correct bi-directionally

          row = lastCorruptedRow+step;

          areaHeight = lastCorruptedRow-firstCorruptedRow+step;

          // Conceal the corrupted area switching between the up and the bottom rows

          for ( i = 0; i < areaHeight; i += step )

          {

            if ( i % 2 )

            {

              currRow = lastCorruptedRow;

              lastCorruptedRow -= step;

            }

            else

            {

              currRow = firstCorruptedRow;

              firstCorruptedRow += step;

            }

            if (smoothColumn > 0)

            {

              srcCounter = ercCollectColumnBlocks( predBlocks, currRow, column, condition, lastRow, lastColumn, step );

            }

            else

            {

              srcCounter = ercCollect8PredBlocks( predBlocks, currRow, column, condition, lastRow, lastColumn, step, 1 );

            }

            switch( comp )

            {

            case 0 :

              ercPixConcealIMB( recfr->yptr, currRow, column, predBlocks, picSizeX, 2 );

              break;

            case 1 :

              ercPixConcealIMB( recfr->uptr, currRow, column, predBlocks, (picSizeX>>1), 1 );

              break;

            case 2 :

              ercPixConcealIMB( recfr->vptr, currRow, column, predBlocks, (picSizeX>>1), 1 );

              break;

            }

            if ( comp == 0 )

            {

              condition[ currRow*lastColumn+column] = ERC_BLOCK_CONCEALED;

              condition[ currRow*lastColumn+column + 1] = ERC_BLOCK_CONCEALED;

              condition[ currRow*lastColumn+column + lastColumn] = ERC_BLOCK_CONCEALED;

              condition[ currRow*lastColumn+column + lastColumn + 1] = ERC_BLOCK_CONCEALED;

            }

            else

            {

              condition[ currRow*lastColumn+column ] = ERC_BLOCK_CONCEALED;

            }

          }

        }

        lastCorruptedRow = -1;

        firstCorruptedRow = -1;

      }

    }

  }

}

/*!

 ************************************************************************

 * \brief

 *      Does the actual pixel based interpolation for block[]

 *      using weighted average

 * \param src[]

 *      pointers to neighboring source blocks

 * \param block

 *      destination block

 * \param blockSize

 *      16 for Y, 8 for U/V components

 * \param frameWidth

 *      Width of the frame in pixels

 ************************************************************************

 */

static void pixMeanInterpolateBlock( imgpel *src[], imgpel *block, int blockSize, int frameWidth )

{

  int row, column, k, tmp, srcCounter = 0, weight = 0, bmax = blockSize - 1;

  k = 0;

  for ( row = 0; row < blockSize; row++ )

  {

    for ( column = 0; column < blockSize; column++ )

    {

      tmp = 0;

      srcCounter = 0;

      // above

      if ( src[4] != NULL )

      {

        weight = blockSize-row;

        tmp += weight * (*(src[4]+bmax*frameWidth+column));

        srcCounter += weight;

      }

      // left

      if ( src[5] != NULL )

      {

        weight = blockSize-column;

        tmp += weight * (*(src[5]+row*frameWidth+bmax));

        srcCounter += weight;

      }

      // below

      if ( src[6] != NULL )

      {

        weight = row+1;

        tmp += weight * (*(src[6]+column));

        srcCounter += weight;

      }

      // right

      if ( src[7] != NULL )

      {

        weight = column+1;

        tmp += weight * (*(src[7]+row*frameWidth));

        srcCounter += weight;

      }

      if ( srcCounter > 0 )

        block[ k + column ] = (byte)(tmp/srcCounter);

      else

        block[ k + column ] = blockSize == 8 ? img->dc_pred_value_chroma : img->dc_pred_value_luma;

    }

    k += frameWidth;

  }

}