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📄 transform8x8.c

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/*!
 ***************************************************************************
 * \file transform8x8.c
 *
 * \brief
 *    8x8 transform functions
 *
 * \author
 *    Main contributors (see contributors.h for copyright, address and affiliation details)
 *    - Yuri Vatis
 *    - Jan Muenster
 *
 * \date
 *    12. October 2003
 **************************************************************************
 */

#include "global.h"

#include "image.h"
#include "mb_access.h"
#include "elements.h"
#include "transform8x8.h"
#include "transform.h"
#include "quant.h"



// function declarations
void   LowPassForIntra8x8Pred(imgpel *PredPel, int block_up_left, int block_up, int block_left);


// Notation for comments regarding prediction and predictors.
// The pels of the 4x4 block are labeled a..p. The predictor pels above
// are labeled A..H, from the left I..P, and from above left X, as follows:
//
//  Z  A  B  C  D  E  F  G  H  I  J  K  L  M   N  O  P
//  Q  a1 b1 c1 d1 e1 f1 g1 h1
//  R  a2 b2 c2 d2 e2 f2 g2 h2
//  S  a3 b3 c3 d3 e3 f3 g3 h3
//  T  a4 b4 c4 d4 e4 f4 g4 h4
//  U  a5 b5 c5 d5 e5 f5 g5 h5
//  V  a6 b6 c6 d6 e6 f6 g6 h6
//  W  a7 b7 c7 d7 e7 f7 g7 h7
//  X  a8 b8 c8 d8 e8 f8 g8 h8


// Predictor array index definitions
#define P_Z (PredPel[0])
#define P_A (PredPel[1])
#define P_B (PredPel[2])
#define P_C (PredPel[3])
#define P_D (PredPel[4])
#define P_E (PredPel[5])
#define P_F (PredPel[6])
#define P_G (PredPel[7])
#define P_H (PredPel[8])
#define P_I (PredPel[9])
#define P_J (PredPel[10])
#define P_K (PredPel[11])
#define P_L (PredPel[12])
#define P_M (PredPel[13])
#define P_N (PredPel[14])
#define P_O (PredPel[15])
#define P_P (PredPel[16])
#define P_Q (PredPel[17])
#define P_R (PredPel[18])
#define P_S (PredPel[19])
#define P_T (PredPel[20])
#define P_U (PredPel[21])
#define P_V (PredPel[22])
#define P_W (PredPel[23])
#define P_X (PredPel[24])

/*!
 ************************************************************************
 * \brief
 *    Make intra 8x8 prediction according to all 9 prediction modes.
 *    The routine uses left and upper neighbouring points from
 *    previous coded blocks to do this (if available). Notice that
 *    inaccessible neighbouring points are signalled with a negative
 *    value in the predmode array .
 *
 *  \par Input:
 *     Starting point of current 8x8 block image position
 *
 ************************************************************************
 */
int intrapred8x8(ImageParameters *img,  //!< image parameters
                 Macroblock *currMB,   //!< Current Macroblock 
                 ColorPlane pl,        //!< Current Colorplane                 
                 int b8)

{
  int i,j;
  int s0;
  imgpel PredPel[25];  // array of predictor pels
  int uv = pl-1;
  imgpel **imgY = (pl) ? dec_picture->imgUV[uv] : dec_picture->imgY; // For MB level frame/field coding tools -- set default to imgY

  PixelPos pix_a[8];
  PixelPos pix_b, pix_c, pix_d;

  int block_available_up;
  int block_available_left;
  int block_available_up_left;
  int block_available_up_right;
  int img_block_x = (img->mb_x << 2) + ((b8 & 0x01) << 1);
  int img_block_y = (img->mb_y << 2) + ((b8  >>  1) << 1);
  int ioff = (b8 & 0x01) << 3;
  int joff = (b8 >> 1  ) << 3;
  int jpos0 = joff    , jpos1 = joff + 1, jpos2 = joff + 2, jpos3 = joff + 3;
  int jpos4 = joff + 4, jpos5 = joff + 5, jpos6 = joff + 6, jpos7 = joff + 7;
  int ipos0 = ioff    , ipos1 = ioff + 1, ipos2 = ioff + 2, ipos3 = ioff + 3;
  int ipos4 = ioff + 4, ipos5 = ioff + 5, ipos6 = ioff + 6, ipos7 = ioff + 7;
  int jpos, ipos;
  imgpel *pred_pels, (*mpr)[16] = img->mb_pred[pl];
  int *mb_size = img->mb_size[IS_LUMA];

  byte predmode = img->ipredmode[img_block_y][img_block_x];
  ipmode_DPCM = predmode;  //For residual DPCM

  for (i=0;i<8;i++)
  {
    getNeighbour(currMB, ioff - 1, joff + i, mb_size, &pix_a[i]);
  }

  getNeighbour(currMB, ioff    , joff - 1, mb_size, &pix_b);
  getNeighbour(currMB, ioff + 8, joff - 1, mb_size, &pix_c);
  getNeighbour(currMB, ioff - 1, joff - 1, mb_size, &pix_d);

  pix_c.available = pix_c.available &&!(ioff == 8 && joff == 8);

  if (active_pps->constrained_intra_pred_flag)
  {
    for (i=0, block_available_left=1; i<8;i++)
      block_available_left  &= pix_a[i].available ? img->intra_block[pix_a[i].mb_addr]: 0;
    block_available_up       = pix_b.available ? img->intra_block [pix_b.mb_addr] : 0;
    block_available_up_right = pix_c.available ? img->intra_block [pix_c.mb_addr] : 0;
    block_available_up_left  = pix_d.available ? img->intra_block [pix_d.mb_addr] : 0;
  }
  else
  {
    block_available_left     = pix_a[0].available;
    block_available_up       = pix_b.available;
    block_available_up_right = pix_c.available;
    block_available_up_left  = pix_d.available;
  }

  // form predictor pels
  if (block_available_up)
  {
    pred_pels = &imgY[pix_b.pos_y][pix_b.pos_x];
    P_A = pred_pels[0];
    P_B = pred_pels[1];
    P_C = pred_pels[2];
    P_D = pred_pels[3];
    P_E = pred_pels[4];
    P_F = pred_pels[5];
    P_G = pred_pels[6];
    P_H = pred_pels[7];
  }
  else
  {
    P_A = P_B = P_C = P_D = P_E = P_F = P_G = P_H = (imgpel) img->dc_pred_value_comp[pl];
  }

  if (block_available_up_right)
  {
    pred_pels = &imgY[pix_c.pos_y][pix_c.pos_x];
    P_I = pred_pels[0];
    P_J = pred_pels[1];
    P_K = pred_pels[2];
    P_L = pred_pels[3];
    P_M = pred_pels[4];
    P_N = pred_pels[5];
    P_O = pred_pels[6];
    P_P = pred_pels[7];

  }
  else
  {
    P_I = P_J = P_K = P_L = P_M = P_N = P_O = P_P = P_H;
  }

  if (block_available_left)
  {
    P_Q = imgY[pix_a[0].pos_y][pix_a[0].pos_x];
    P_R = imgY[pix_a[1].pos_y][pix_a[1].pos_x];
    P_S = imgY[pix_a[2].pos_y][pix_a[2].pos_x];
    P_T = imgY[pix_a[3].pos_y][pix_a[3].pos_x];
    P_U = imgY[pix_a[4].pos_y][pix_a[4].pos_x];
    P_V = imgY[pix_a[5].pos_y][pix_a[5].pos_x];
    P_W = imgY[pix_a[6].pos_y][pix_a[6].pos_x];
    P_X = imgY[pix_a[7].pos_y][pix_a[7].pos_x];
  }
  else
  {
    P_Q = P_R = P_S = P_T = P_U = P_V = P_W = P_X = (imgpel) img->dc_pred_value_comp[pl];
  }

  if (block_available_up_left)
  {
    P_Z = imgY[pix_d.pos_y][pix_d.pos_x];
  }
  else
  {
    P_Z = (imgpel) img->dc_pred_value_comp[pl];
  }

  LowPassForIntra8x8Pred(&(P_Z), block_available_up_left, block_available_up, block_available_left);

  switch(predmode)
  {
  case DC_PRED:
    s0 = 0;
    if (block_available_up && block_available_left)
    {
      // no edge
      s0 = (P_A + P_B + P_C + P_D + P_E + P_F + P_G + P_H + P_Q + P_R + P_S + P_T + P_U + P_V + P_W + P_X + 8) >> 4;
    }
    else if (!block_available_up && block_available_left)
    {
      // upper edge
      s0 = (P_Q + P_R + P_S + P_T + P_U + P_V + P_W + P_X + 4) >> 3;
    }
    else if (block_available_up && !block_available_left)
    {
      // left edge
      s0 = (P_A + P_B + P_C + P_D + P_E + P_F + P_G + P_H + 4) >> 3;
    }
    else //if (!block_available_up && !block_available_left)
    {
      // top left corner, nothing to predict from
      s0 = img->dc_pred_value_comp[pl];
    }
    for(j = joff; j < joff + BLOCK_SIZE_8x8; j++)
      for(i = ioff; i < ioff + BLOCK_SIZE_8x8; i++)
        mpr[j][i] = (imgpel) s0;
    break;
  case VERT_PRED:
    if (!block_available_up)
      printf ("warning: Intra_8x8_Vertical prediction mode not allowed at mb %d\n", (int) img->current_mb_nr);

    for (i=0; i < BLOCK_SIZE_8x8; i++)
    {
      ipos = i+ioff;
      mpr[jpos0][ipos] =
      mpr[jpos1][ipos] =
      mpr[jpos2][ipos] =
      mpr[jpos3][ipos] =
      mpr[jpos4][ipos] =
      mpr[jpos5][ipos] =
      mpr[jpos6][ipos] =
      mpr[jpos7][ipos] = (imgpel) (&P_A)[i];
    }
    break;
  case HOR_PRED:
    if (!block_available_left)
      printf ("warning: Intra_8x8_Horizontal prediction mode not allowed at mb %d\n", (int) img->current_mb_nr);

    for (j=0; j < BLOCK_SIZE_8x8; j++)
    {
      jpos = j + joff;
      mpr[jpos][ipos0]  =
      mpr[jpos][ipos1]  =
      mpr[jpos][ipos2]  =
      mpr[jpos][ipos3]  =
      mpr[jpos][ipos4]  =
      mpr[jpos][ipos5]  =
      mpr[jpos][ipos6]  =
      mpr[jpos][ipos7]  = (imgpel) (&P_Q)[j];
    }
    break;

  case DIAG_DOWN_LEFT_PRED:
    if (!block_available_up)
      printf ("warning: Intra_8x8_Diagonal_Down_Left prediction mode not allowed at mb %d\n", (int) img->current_mb_nr);
    // Mode DIAG_DOWN_LEFT_PRED
    mpr[jpos0][ipos0] = (imgpel) ((P_A + P_C + 2*(P_B) + 2) >> 2);
    mpr[jpos1][ipos0] =
    mpr[jpos0][ipos1] = (imgpel) ((P_B + P_D + 2*(P_C) + 2) >> 2);
    mpr[jpos2][ipos0] =
    mpr[jpos1][ipos1] =
    mpr[jpos0][ipos2] = (imgpel) ((P_C + P_E + 2*(P_D) + 2) >> 2);
    mpr[jpos3][ipos0] =
    mpr[jpos2][ipos1] =
    mpr[jpos1][ipos2] =
    mpr[jpos0][ipos3] = (imgpel) ((P_D + P_F + 2*(P_E) + 2) >> 2);
    mpr[jpos4][ipos0] =
    mpr[jpos3][ipos1] =
    mpr[jpos2][ipos2] =
    mpr[jpos1][ipos3] =
    mpr[jpos0][ipos4] = (imgpel) ((P_E + P_G + 2*(P_F) + 2) >> 2);
    mpr[jpos5][ipos0] =
    mpr[jpos4][ipos1] =
    mpr[jpos3][ipos2] =
    mpr[jpos2][ipos3] =
    mpr[jpos1][ipos4] =
    mpr[jpos0][ipos5] = (imgpel) ((P_F + P_H + 2*(P_G) + 2) >> 2);
    mpr[jpos6][ipos0] =
    mpr[jpos5][ipos1] =
    mpr[jpos4][ipos2] =
    mpr[jpos3][ipos3] =
    mpr[jpos2][ipos4] =
    mpr[jpos1][ipos5] =
    mpr[jpos0][ipos6] = (imgpel) ((P_G + P_I + 2*(P_H) + 2) >> 2);
    mpr[jpos7][ipos0] =
    mpr[jpos6][ipos1] =
    mpr[jpos5][ipos2] =
    mpr[jpos4][ipos3] =
    mpr[jpos3][ipos4] =
    mpr[jpos2][ipos5] =
    mpr[jpos1][ipos6] =
    mpr[jpos0][ipos7] = (imgpel) ((P_H + P_J + 2*(P_I) + 2) >> 2);
    mpr[jpos7][ipos1] =
    mpr[jpos6][ipos2] =
    mpr[jpos5][ipos3] =
    mpr[jpos4][ipos4] =
    mpr[jpos3][ipos5] =
    mpr[jpos2][ipos6] =
    mpr[jpos1][ipos7] = (imgpel) ((P_I + P_K + 2*(P_J) + 2) >> 2);
    mpr[jpos7][ipos2] =
    mpr[jpos6][ipos3] =
    mpr[jpos5][ipos4] =
    mpr[jpos4][ipos5] =
    mpr[jpos3][ipos6] =
    mpr[jpos2][ipos7] = (imgpel) ((P_J + P_L + 2*(P_K) + 2) >> 2);
    mpr[jpos7][ipos3] =
    mpr[jpos6][ipos4] =
    mpr[jpos5][ipos5] =
    mpr[jpos4][ipos6] =
    mpr[jpos3][ipos7] = (imgpel) ((P_K + P_M + 2*(P_L) + 2) >> 2);
    mpr[jpos7][ipos4] =
    mpr[jpos6][ipos5] =
    mpr[jpos5][ipos6] =
    mpr[jpos4][ipos7] = (imgpel) ((P_L + P_N + 2*(P_M) + 2) >> 2);
    mpr[jpos7][ipos5] =
    mpr[jpos6][ipos6] =
    mpr[jpos5][ipos7] = (imgpel) ((P_M + P_O + 2*(P_N) + 2) >> 2);
    mpr[jpos7][ipos6] =
    mpr[jpos6][ipos7] = (imgpel) ((P_N + P_P + 2*(P_O) + 2) >> 2);
    mpr[jpos7][ipos7] = (imgpel) ((P_O + 3*(P_P) + 2) >> 2);
    break;

  case VERT_LEFT_PRED:
    if (!block_available_up)
      printf ("warning: Intra_4x4_Vertical_Left prediction mode not allowed at mb %d\n", (int) img->current_mb_nr);

    mpr[jpos0][ipos0] = (imgpel) ((P_A + P_B + 1) >> 1);
    mpr[jpos0][ipos1] =
    mpr[jpos2][ipos0] = (imgpel) ((P_B + P_C + 1) >> 1);
    mpr[jpos0][ipos2] =
    mpr[jpos2][ipos1] =
    mpr[jpos4][ipos0] = (imgpel) ((P_C + P_D + 1) >> 1);
    mpr[jpos0][ipos3] =
    mpr[jpos2][ipos2] =
    mpr[jpos4][ipos1] =
    mpr[jpos6][ipos0] = (imgpel) ((P_D + P_E + 1) >> 1);
    mpr[jpos0][ipos4] =
    mpr[jpos2][ipos3] =
    mpr[jpos4][ipos2] =
    mpr[jpos6][ipos1] = (imgpel) ((P_E + P_F + 1) >> 1);
    mpr[jpos0][ipos5] =
    mpr[jpos2][ipos4] =
    mpr[jpos4][ipos3] =
    mpr[jpos6][ipos2] = (imgpel) ((P_F + P_G + 1) >> 1);
    mpr[jpos0][ipos6] =
    mpr[jpos2][ipos5] =
    mpr[jpos4][ipos4] =
    mpr[jpos6][ipos3] = (imgpel) ((P_G + P_H + 1) >> 1);
    mpr[jpos0][ipos7] =
    mpr[jpos2][ipos6] =
    mpr[jpos4][ipos5] =
    mpr[jpos6][ipos4] = (imgpel) ((P_H + P_I + 1) >> 1);
    mpr[jpos2][ipos7] =
    mpr[jpos4][ipos6] =
    mpr[jpos6][ipos5] = (imgpel) ((P_I + P_J + 1) >> 1);
    mpr[jpos4][ipos7] =
    mpr[jpos6][ipos6] = (imgpel) ((P_J + P_K + 1) >> 1);
    mpr[jpos6][ipos7] = (imgpel) ((P_K + P_L + 1) >> 1);
    mpr[jpos1][ipos0] = (imgpel) ((P_A + P_C + 2*P_B + 2) >> 2);
    mpr[jpos1][ipos1] =
    mpr[jpos3][ipos0] = (imgpel) ((P_B + P_D + 2*P_C + 2) >> 2);
    mpr[jpos1][ipos2] =
    mpr[jpos3][ipos1] =
    mpr[jpos5][ipos0] = (imgpel) ((P_C + P_E + 2*P_D + 2) >> 2);
    mpr[jpos1][ipos3] =
    mpr[jpos3][ipos2] =
    mpr[jpos5][ipos1] =
    mpr[jpos7][ipos0] = (imgpel) ((P_D + P_F + 2*P_E + 2) >> 2);
    mpr[jpos1][ipos4] =
    mpr[jpos3][ipos3] =
    mpr[jpos5][ipos2] =
    mpr[jpos7][ipos1] = (imgpel) ((P_E + P_G + 2*P_F + 2) >> 2);
    mpr[jpos1][ipos5] =
    mpr[jpos3][ipos4] =
    mpr[jpos5][ipos3] =
    mpr[jpos7][ipos2] = (imgpel) ((P_F + P_H + 2*P_G + 2) >> 2);
    mpr[jpos1][ipos6] =
    mpr[jpos3][ipos5] =
    mpr[jpos5][ipos4] =
    mpr[jpos7][ipos3] = (imgpel) ((P_G + P_I + 2*P_H + 2) >> 2);
    mpr[jpos1][ipos7] =
    mpr[jpos3][ipos6] =

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