block.c

H.264编码实现

/*!
 ***********************************************************************
 *  \file
 *      block.c
 *
 *  \brief
 *      Block functions
 *
 *  \author
 *      Main contributors (see contributors.h for copyright, address and affiliation details)
 *      - Inge Lille-Langoy          <[e-mail]>
 *      - Rickard Sjoberg            <[e-mail]>
 ***********************************************************************
 */

#include "contributors.h"

#include "global.h"
#include "block.h"
#include "image.h"
#include "mb_access.h"
#include "transform.h"
#include "quant.h"

// Notation for comments regarding prediction and predictors.
// The pels of the 4x4 block are labelled a..p. The predictor pels above
// are labelled A..H, from the left I..L, and from above left X, as follows:
//
//  X A B C D E F G H
//  I a b c d
//  J e f g h
//  K i j k l
//  L m n o p
//

// Predictor array index definitions
#define P_X (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])

  static int M4[BLOCK_SIZE][BLOCK_SIZE];
  static int PBlock[MB_BLOCK_SIZE][MB_BLOCK_SIZE];

static void intra_chroma_DC_single(imgpel **curr_img, int up_avail, int left_avail, PixelPos up, PixelPos left[17], int blk_x, int blk_y, int *pred, int direction )
{
  static int i;
  int s0 = 0;

  if ((direction && up_avail) || (!left_avail && up_avail))
  {
    for (i = blk_x; i < (blk_x + 4);i++)  
      s0 += curr_img[up.pos_y][up.pos_x + i];
    *pred = (s0 + 2) >> 2;
  }
  else if (left_avail)  
  {
    for (i = blk_y; i < (blk_y + 4);i++)  
      s0 += curr_img[left[i].pos_y][left[i].pos_x];
    *pred = (s0 + 2) >> 2;
  }
}


static void intra_chroma_DC_all(imgpel **curr_img, int up_avail, int left_avail, PixelPos up, PixelPos left[17], int blk_x, int blk_y, int *pred )
{
  static int i;
  int s0 = 0, s1 = 0;

  if (up_avail)       
    for (i = blk_x; i < (blk_x + 4);i++)  
      s0 += curr_img[up.pos_y][up.pos_x + i];
  
  if (left_avail)  
    for (i = blk_y; i < (blk_y + 4);i++)  
      s1 += curr_img[left[i].pos_y][left[i].pos_x];
  
  if (up_avail && left_avail)
    *pred = (s0 + s1 + 4) >> 3;
  else if (up_avail)
    *pred = (s0 + 2) >> 2;
  else if (left_avail)
    *pred = (s1 + 2) >> 2;
}

/*!
 ***********************************************************************
 * \brief
 *    makes and returns 4x4 blocks with all 5 intra prediction modes
 *
 * \return
 *    DECODING_OK   decoding of intraprediction mode was sucessfull            \n
 *    SEARCH_SYNC   search next sync element as errors while decoding occured
 ***********************************************************************
 */
int intrapred(ImageParameters *img,  //!< image parameters 
              Macroblock *currMB, 
              ColorPlane pl,               
              int ioff,             //!< pixel offset X within MB
              int joff,             //!< pixel offset Y within MB
              int img_block_x,      //!< location of block X, multiples of 4
              int img_block_y)      //!< location of block Y, multiples of 4
{
  int i,j;
  int s0;  
  imgpel PredPel[13];  // array of predictor pels
  int uv = pl-1;
  imgpel **imgY = (pl) ? dec_picture->imgUV[uv] : dec_picture->imgY;

  PixelPos pix_a[4];
  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;

  byte predmode = img->ipredmode[img_block_y][img_block_x];
  int jpos0 = joff, jpos1 = joff + 1, jpos2 = joff + 2, jpos3 = joff + 3;
  int ipos0 = ioff, ipos1 = ioff + 1, ipos2 = ioff + 2, ipos3 = ioff + 3;
  imgpel *predrow, prediction, (*mpr)[16] = img->mb_pred[pl];

  ipmode_DPCM = predmode; //For residual DPCM

  for (i=0;i<4;i++)
  {
    getNeighbour(currMB, ioff -1 , joff +i , img->mb_size[IS_LUMA], &pix_a[i]);
  }

  getNeighbour(currMB, ioff    , joff -1 , img->mb_size[IS_LUMA], &pix_b);
  getNeighbour(currMB, ioff +4 , joff -1 , img->mb_size[IS_LUMA], &pix_c);
  getNeighbour(currMB, ioff -1 , joff -1 , img->mb_size[IS_LUMA], &pix_d);

  pix_c.available = pix_c.available && !((ioff==4) && ((joff==4)||(joff==12)));

  if (active_pps->constrained_intra_pred_flag)
  {
    for (i=0, block_available_left=1; i<4;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)
  {
    P_A = imgY[pix_b.pos_y][pix_b.pos_x + 0];
    P_B = imgY[pix_b.pos_y][pix_b.pos_x + 1];
    P_C = imgY[pix_b.pos_y][pix_b.pos_x + 2];
    P_D = imgY[pix_b.pos_y][pix_b.pos_x + 3];

  }
  else
  {
    P_A = P_B = P_C = P_D = (imgpel) img->dc_pred_value_comp[pl];
  }

  if (block_available_up_right)
  {
    P_E = imgY[pix_c.pos_y][pix_c.pos_x + 0];
    P_F = imgY[pix_c.pos_y][pix_c.pos_x + 1];
    P_G = imgY[pix_c.pos_y][pix_c.pos_x + 2];
    P_H = imgY[pix_c.pos_y][pix_c.pos_x + 3];
  }
  else
  {
    P_E = P_F = P_G = P_H = P_D;
  }

  if (block_available_left)
  {
    P_I = imgY[pix_a[0].pos_y][pix_a[0].pos_x];
    P_J = imgY[pix_a[1].pos_y][pix_a[1].pos_x];
    P_K = imgY[pix_a[2].pos_y][pix_a[2].pos_x];
    P_L = imgY[pix_a[3].pos_y][pix_a[3].pos_x];
  }
  else
  {
    P_I = P_J = P_K = P_L = (imgpel) img->dc_pred_value_comp[pl];
  }

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


  switch (predmode)
  {
  case DC_PRED:                         /* DC prediction */

    s0 = 0;
    if (block_available_up && block_available_left)
    {
      // no edge
      s0 = (P_A + P_B + P_C + P_D + P_I + P_J + P_K + P_L + 4)>>3;
    }
    else if (!block_available_up && block_available_left)
    {
      // upper edge
      s0 = (P_I + P_J + P_K + P_L + 2)>>2;
    }
    else if (block_available_up && !block_available_left)
    {
      // left edge
      s0 = (P_A + P_B + P_C + P_D + 2)>>2;
    }
    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; j++)
    {
      for (i=ioff; i < ioff + BLOCK_SIZE; i++)
      {
        // store DC prediction
        mpr[j][i] = (imgpel) s0;
      }
    }
    break;

  case VERT_PRED:                       /* vertical prediction from block above */
    if (!block_available_up)
      printf ("warning: Intra_4x4_Vertical prediction mode not allowed at mb %d\n", (int) img->current_mb_nr);

    for(j = joff; j < joff + BLOCK_SIZE; j++) /* store predicted 4x4 block */
      memcpy(&(mpr[j][ioff]), &(imgY[pix_b.pos_y][pix_b.pos_x]), BLOCK_SIZE * sizeof(imgpel));
    break;

  case HOR_PRED:                        /* horizontal prediction from left block */
    if (!block_available_left)
      printf ("warning: Intra_4x4_Horizontal prediction mode not allowed at mb %d\n",(int) img->current_mb_nr);

    for(j=0;j<BLOCK_SIZE;j++)
    {
      predrow = mpr[j+joff];
      prediction = imgY[pix_a[j].pos_y][pix_a[j].pos_x];
      for(i = ioff;i < ioff + BLOCK_SIZE;i++)
        predrow[i]= prediction; /* store predicted 4x4 block */
    }
    break;

  case DIAG_DOWN_RIGHT_PRED:
    if ((!block_available_up)||(!block_available_left)||(!block_available_up_left))
      printf ("warning: Intra_4x4_Diagonal_Down_Right prediction mode not allowed at mb %d\n",(int) img->current_mb_nr);

    mpr[jpos3][ipos0] = (imgpel) ((P_L + 2*P_K + P_J + 2) >> 2);
    mpr[jpos2][ipos0] =
    mpr[jpos3][ipos1] = (imgpel) ((P_K + 2*P_J + P_I + 2) >> 2);
    mpr[jpos1][ipos0] =
    mpr[jpos2][ipos1] =
    mpr[jpos3][ipos2] = (imgpel) ((P_J + 2*P_I + P_X + 2) >> 2);
    mpr[jpos0][ipos0] =
    mpr[jpos1][ipos1] =
    mpr[jpos2][ipos2] =
    mpr[jpos3][ipos3] = (imgpel) ((P_I + 2*P_X + P_A + 2) >> 2);
    mpr[jpos0][ipos1] =
    mpr[jpos1][ipos2] =
    mpr[jpos2][ipos3] = (imgpel) ((P_X + 2*P_A + P_B + 2) >> 2);
    mpr[jpos0][ipos2] =
    mpr[jpos1][ipos3] = (imgpel) ((P_A + 2*P_B + P_C + 2) >> 2);
    mpr[jpos0][ipos3] = (imgpel) ((P_B + 2*P_C + P_D + 2) >> 2);
    break;

  case DIAG_DOWN_LEFT_PRED:
    if (!block_available_up)
      printf ("warning: Intra_4x4_Diagonal_Down_Left prediction mode not allowed at mb %d\n", (int) img->current_mb_nr);

    mpr[jpos0][ipos0] = (imgpel) ((P_A + P_C + 2*(P_B) + 2) >> 2);
    mpr[jpos0][ipos1] =
    mpr[jpos1][ipos0] = (imgpel) ((P_B + P_D + 2*(P_C) + 2) >> 2);
    mpr[jpos0][ipos2] =
    mpr[jpos1][ipos1] =
    mpr[jpos2][ipos0] = (imgpel) ((P_C + P_E + 2*(P_D) + 2) >> 2);
    mpr[jpos0][ipos3] =
    mpr[jpos1][ipos2] =
    mpr[jpos2][ipos1] =
    mpr[jpos3][ipos0] = (imgpel) ((P_D + P_F + 2*(P_E) + 2) >> 2);
    mpr[jpos1][ipos3] =
    mpr[jpos2][ipos2] =
    mpr[jpos3][ipos1] = (imgpel) ((P_E + P_G + 2*(P_F) + 2) >> 2);
    mpr[jpos2][ipos3] =
    mpr[jpos3][ipos2] = (imgpel) ((P_F + P_H + 2*(P_G) + 2) >> 2);
    mpr[jpos3][ipos3] = (imgpel) ((P_G + 3*(P_H) + 2) >> 2);
    break;

  case  VERT_RIGHT_PRED:/* diagonal prediction -22.5 deg to horizontal plane */
    if ((!block_available_up)||(!block_available_left)||(!block_available_up_left))
      printf ("warning: Intra_4x4_Vertical_Right prediction mode not allowed at mb %d\n", (int) img->current_mb_nr);

    mpr[jpos0][ipos0] =
    mpr[jpos2][ipos1] = (imgpel) ((P_X + P_A + 1) >> 1);
    mpr[jpos0][ipos1] =
    mpr[jpos2][ipos2] = (imgpel) ((P_A + P_B + 1) >> 1);
    mpr[jpos0][ipos2] =
    mpr[jpos2][ipos3] = (imgpel) ((P_B + P_C + 1) >> 1);
    mpr[jpos0][ipos3] = (imgpel) ((P_C + P_D + 1) >> 1);
    mpr[jpos1][ipos0] =
    mpr[jpos3][ipos1] = (imgpel) ((P_I + 2*P_X + P_A + 2) >> 2);
    mpr[jpos1][ipos1] =
    mpr[jpos3][ipos2] = (imgpel) ((P_X + 2*P_A + P_B + 2) >> 2);
    mpr[jpos1][ipos2] =
    mpr[jpos3][ipos3] = (imgpel) ((P_A + 2*P_B + P_C + 2) >> 2);
    mpr[jpos1][ipos3] = (imgpel) ((P_B + 2*P_C + P_D + 2) >> 2);
    mpr[jpos2][ipos0] = (imgpel) ((P_X + 2*P_I + P_J + 2) >> 2);
    mpr[jpos3][ipos0] = (imgpel) ((P_I + 2*P_J + P_K + 2) >> 2);
    break;

  case  VERT_LEFT_PRED:/* diagonal prediction -22.5 deg to horizontal plane */
    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] = (imgpel) ((P_C + P_D + 1) >> 1);
    mpr[jpos0][ipos3] =
    mpr[jpos2][ipos2] = (imgpel) ((P_D + P_E + 1) >> 1);
    mpr[jpos2][ipos3] = (imgpel) ((P_E + P_F + 1) >> 1);
    mpr[jpos1][ipos0] = (imgpel) ((P_A + 2*P_B + P_C + 2) >> 2);
    mpr[jpos1][ipos1] =
    mpr[jpos3][ipos0] = (imgpel) ((P_B + 2*P_C + P_D + 2) >> 2);
    mpr[jpos1][ipos2] =
    mpr[jpos3][ipos1] = (imgpel) ((P_C + 2*P_D + P_E + 2) >> 2);
    mpr[jpos1][ipos3] =
    mpr[jpos3][ipos2] = (imgpel) ((P_D + 2*P_E + P_F + 2) >> 2);
    mpr[jpos3][ipos3] = (imgpel) ((P_E + 2*P_F + P_G + 2) >> 2);
    break;

  case  HOR_UP_PRED:/* diagonal prediction -22.5 deg to horizontal plane */
    if (!block_available_left)
      printf ("warning: Intra_4x4_Horizontal_Up prediction mode not allowed at mb %d\n",(int) img->current_mb_nr);

    mpr[jpos0][ipos0] = (imgpel) ((P_I + P_J + 1) >> 1);
    mpr[jpos0][ipos1] = (imgpel) ((P_I + 2*P_J + P_K + 2) >> 2);
    mpr[jpos0][ipos2] =
    mpr[jpos1][ipos0] = (imgpel) ((P_J + P_K + 1) >> 1);
    mpr[jpos0][ipos3] =
    mpr[jpos1][ipos1] = (imgpel) ((P_J + 2*P_K + P_L + 2) >> 2);
    mpr[jpos1][ipos2] =
    mpr[jpos2][ipos0] = (imgpel) ((P_K + P_L + 1) >> 1);
    mpr[jpos1][ipos3] =
    mpr[jpos2][ipos1] = (imgpel) ((P_K + 2*P_L + P_L + 2) >> 2);
    mpr[jpos2][ipos3] =
    mpr[jpos3][ipos1] =
    mpr[jpos3][ipos0] =
    mpr[jpos2][ipos2] =
    mpr[jpos3][ipos2] =
    mpr[jpos3][ipos3] = (imgpel) P_L;
    break;

  case  HOR_DOWN_PRED:/* diagonal prediction -22.5 deg to horizontal plane */
    if ((!block_available_up)||(!block_available_left)||(!block_available_up_left))
      printf ("warning: Intra_4x4_Horizontal_Down prediction mode not allowed at mb %d\n", (int) img->current_mb_nr);

    mpr[jpos0][ipos0] =
    mpr[jpos1][ipos2] = (imgpel) ((P_X + P_I + 1) >> 1);
    mpr[jpos0][ipos1] =
    mpr[jpos1][ipos3] = (imgpel) ((P_I + 2*P_X + P_A + 2) >> 2);
    mpr[jpos0][ipos2] = (imgpel) ((P_X + 2*P_A + P_B + 2) >> 2);
    mpr[jpos0][ipos3] = (imgpel) ((P_A + 2*P_B + P_C + 2) >> 2);
    mpr[jpos1][ipos0] =
    mpr[jpos2][ipos2] = (imgpel) ((P_I + P_J + 1) >> 1);
    mpr[jpos1][ipos1] =
    mpr[jpos2][ipos3] = (imgpel) ((P_X + 2*P_I + P_J + 2) >> 2);
    mpr[jpos2][ipos0] =
    mpr[jpos3][ipos2] = (imgpel) ((P_J + P_K + 1) >> 1);
    mpr[jpos2][ipos1] =
    mpr[jpos3][ipos3] = (imgpel) ((P_I + 2*P_J + P_K + 2) >> 2);
    mpr[jpos3][ipos0] = (imgpel) ((P_K + P_L + 1) >> 1);
    mpr[jpos3][ipos1] = (imgpel) ((P_J + 2*P_K + P_L + 2) >> 2);
    break;

  default:
    printf("Error: illegal intra_4x4 prediction mode: %d\n", (int) predmode);
    return SEARCH_SYNC;
    break;
  }

  return DECODING_OK;
}


/*!
 ***********************************************************************
 * \return
 *    best SAD
 ***********************************************************************
 */ 
int intrapred_luma_16x16(ImageParameters *img, //!< image parameters
                         Macroblock *currMB,  //!< Current Macroblock
                         ColorPlane pl,       //!< Current colorplane (for 4:4:4)                         
                         int predmode)        //!< prediction mode
{
  int s0 = 0, s1, s2;

  int i,j;

  int ih,iv;
  int ib,ic,iaa;

  int uv = pl-1;
  imgpel **imgY = (pl) ? dec_picture->imgUV[uv] : dec_picture->imgY;
  imgpel (*mpr)[MB_BLOCK_SIZE] = &(img->mb_pred[pl][0]); 
  imgpel *mpr_line;
  imgpel prediction;
  int max_imgpel_value = img->max_imgpel_value_comp[pl];

  PixelPos up;          //!< pixel position p(0,-1)