block.c

包含了从MPEG4的视频解码到H.264的视频编码部分的源代码

/*
***********************************************************************
* COPYRIGHT AND WARRANTY INFORMATION
*
* Copyright 2001, International Telecommunications Union, Geneva
*
* DISCLAIMER OF WARRANTY
*
* These software programs are available to the user without any
* license fee or royalty on an "as is" basis. The ITU disclaims
* any and all warranties, whether express, implied, or
* statutory, including any implied warranties of merchantability
* or of fitness for a particular purpose.  In no event shall the
* contributor or the ITU 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 ITU does not represent or warrant that the programs furnished
* hereunder are free of infringement of any third-party patents.
* Commercial implementations of ITU-T Recommendations, including
* shareware, may be subject to royalty fees to patent holders.
* Information regarding the ITU-T patent policy is available from
* the ITU Web site at http://www.itu.int.
*
* THIS IS NOT A GRANT OF PATENT RIGHTS - SEE THE ITU-T PATENT POLICY.
************************************************************************
*/

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

#include "contributors.h"

#include <stdlib.h>
#include <math.h>

#include "block.h"


#define Q_BITS          15

static const int quant_coef[6][4][4] = {
  {{13107, 8066,13107, 8066},{ 8066, 5243, 8066, 5243},{13107, 8066,13107, 8066},{ 8066, 5243, 8066, 5243}},
  {{11916, 7490,11916, 7490},{ 7490, 4660, 7490, 4660},{11916, 7490,11916, 7490},{ 7490, 4660, 7490, 4660}},
  {{10082, 6554,10082, 6554},{ 6554, 4194, 6554, 4194},{10082, 6554,10082, 6554},{ 6554, 4194, 6554, 4194}},
  {{ 9362, 5825, 9362, 5825},{ 5825, 3647, 5825, 3647},{ 9362, 5825, 9362, 5825},{ 5825, 3647, 5825, 3647}},
  {{ 8192, 5243, 8192, 5243},{ 5243, 3355, 5243, 3355},{ 8192, 5243, 8192, 5243},{ 5243, 3355, 5243, 3355}},
  {{ 7282, 4559, 7282, 4559},{ 4559, 2893, 4559, 2893},{ 7282, 4559, 7282, 4559},{ 4559, 2893, 4559, 2893}}
};
static const int A[4][4] = {
  { 16, 20, 16, 20},
  { 20, 25, 20, 25},
  { 16, 20, 16, 20},
  { 20, 25, 20, 25}
};

// 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])

/*!
 ***********************************************************************
 * \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(
  struct img_par *img,  //!< image parameters
  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;
  int img_y,img_x;
  int PredPel[13];  // array of predictor pels

  int block_available_up;
  int block_available_up_right;
  int block_available_left;
  int block_available_up_left; // new

  byte predmode = img->ipredmode[img_block_x+1][img_block_y+1];

  img_x=img_block_x*4;
  img_y=img_block_y*4;
  if (img->mb_field)
  {
  if (img->current_mb_nr%2)
  {
    predmode = img->ipredmode_bot[img_block_x+1][img_block_y+1];

    block_available_up        = (img->ipredmode_bot[img_block_x+1][img_block_y] >=0);
    block_available_up_right  = (img->ipredmode_bot[img_x/BLOCK_SIZE+2][img_y/BLOCK_SIZE] >=0); // ???
    block_available_left      = (img->ipredmode_bot[img_block_x][img_block_y+1] >=0);
    block_available_up_left   = (img->ipredmode_bot[img_block_x][img_block_y] >=0);

    if(img->mb_frame_field_flag && img_x%MB_BLOCK_SIZE == 12 && img_y%MB_BLOCK_SIZE )
      block_available_up_right = 0;
  }
  else
  {
    predmode = img->ipredmode_top[img_block_x+1][img_block_y+1];

    block_available_up        = (img->ipredmode_top[img_block_x+1][img_block_y] >=0);
    block_available_up_right  = (img->ipredmode_top[img_x/BLOCK_SIZE+2][img_y/BLOCK_SIZE] >=0); // ???
    block_available_left      = (img->ipredmode_top[img_block_x][img_block_y+1] >=0);
    block_available_up_left   = (img->ipredmode_top[img_block_x][img_block_y] >=0);

    if(img->mb_frame_field_flag && img_x%MB_BLOCK_SIZE == 12 && img_y%MB_BLOCK_SIZE )
      block_available_up_right = 0;
  }
  }
  else
  {
    block_available_up        = (img->ipredmode[img_block_x+1][img_block_y] >=0);              /// can use frm
    block_available_up_right  = (img->ipredmode[img_x/BLOCK_SIZE+2][img_y/BLOCK_SIZE] >=0); // ???  /// can use frm
    block_available_left      = (img->ipredmode[img_block_x][img_block_y+1] >=0);            /// can use frm
    block_available_up_left   = (img->ipredmode[img_block_x][img_block_y] >=0);

    if(img->mb_frame_field_flag && img_x%MB_BLOCK_SIZE == 12 && img_y%(2*MB_BLOCK_SIZE) )
      block_available_up_right = 0;
  }
  if( img_x+4 == img->width )
  {
    block_available_up_right = 0;
  }

/*
  if(img_x%MB_BLOCK_SIZE == 12 && img->mb_frame_field_flag)
    block_available_up_right = 0;
    */

  i = (img_x & 15);
  j = (img_y & 15);
  if (block_available_up_right)
  {
    if ((i == 4  && j == 4) ||
        (i == 12 && j == 4) ||
        (i == 12 && j == 8) ||
        (i == 4  && j == 12) ||
        (i == 12 && j == 12))
    {
      block_available_up_right = 0;
    }
  }

  // form predictor pels
  if (block_available_up)
  {
    P_A = imgY[img_y-1][img_x+0];
    P_B = imgY[img_y-1][img_x+1];
    P_C = imgY[img_y-1][img_x+2];
    P_D = imgY[img_y-1][img_x+3];

    if (block_available_up_right)
    {
      P_E = imgY[img_y-1][img_x+4];
      P_F = imgY[img_y-1][img_x+5];
      P_G = imgY[img_y-1][img_x+6];
      P_H = imgY[img_y-1][img_x+7];
    }
    else
    {
      P_E = P_F = P_G = P_H = P_D;
    }
  }
  else
  {
    P_A = P_B = P_C = P_D = P_E = P_F = P_G = P_H = 128;
  }

  if (block_available_left)
  {
    P_I = imgY[img_y+0][img_x-1];
    P_J = imgY[img_y+1][img_x-1];
    P_K = imgY[img_y+2][img_x-1];
    P_L = imgY[img_y+3][img_x-1];
  }
  else
  {
    P_I = P_J = P_K = P_L = 128;
  }

  if (block_available_up_left)
  {
    P_X = imgY[img_y-1][img_x-1];
  }
  else
  {
    P_X = 128;
  }

  
  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)/(2*BLOCK_SIZE);
    }
    else if (!block_available_up && block_available_left)
    {
      // upper edge
      s0 = (P_I + P_J + P_K + P_L + 2)/BLOCK_SIZE;             
    }
    else if (block_available_up && !block_available_left)
    {
      // left edge
      s0 = (P_A + P_B + P_C + P_D + 2)/BLOCK_SIZE;             
    }
    else //if (!block_available_up && !block_available_left)
    {
      // top left corner, nothing to predict from
      s0 = 128;                           
    }

    for (j=0; j < BLOCK_SIZE; j++)
    {
      for (i=0; i < BLOCK_SIZE; i++)
      {
        // store DC prediction
        img->mpr[i+ioff][j+joff] = s0;
      }
    }
    break;

  case VERT_PRED:                       /* vertical prediction from block above */
    for(j=0;j<BLOCK_SIZE;j++)
      for(i=0;i<BLOCK_SIZE;i++)
        img->mpr[i+ioff][j+joff]=imgY[img_y-1][img_x+i];/* store predicted 4x4 block */
    break;

  case HOR_PRED:                        /* horisontal prediction from left block */
    for(j=0;j<BLOCK_SIZE;j++)
      for(i=0;i<BLOCK_SIZE;i++)
        img->mpr[i+ioff][j+joff]=imgY[img_y+j][img_x-1]; /* store predicted 4x4 block */
    break;

  case DIAG_DOWN_RIGHT_PRED:
    img->mpr[0+ioff][3+joff] = (P_L + 2*P_K + P_J + 2) / 4; 
    img->mpr[0+ioff][2+joff] =
    img->mpr[1+ioff][3+joff] = (P_K + 2*P_J + P_I + 2) / 4; 
    img->mpr[0+ioff][1+joff] =
    img->mpr[1+ioff][2+joff] = 
    img->mpr[2+ioff][3+joff] = (P_J + 2*P_I + P_X + 2) / 4; 
    img->mpr[0+ioff][0+joff] =
    img->mpr[1+ioff][1+joff] =
    img->mpr[2+ioff][2+joff] =
    img->mpr[3+ioff][3+joff] = (P_I + 2*P_X + P_A + 2) / 4; 
    img->mpr[1+ioff][0+joff] =
    img->mpr[2+ioff][1+joff] =
    img->mpr[3+ioff][2+joff] = (P_X + 2*P_A + P_B + 2) / 4;
    img->mpr[2+ioff][0+joff] =
    img->mpr[3+ioff][1+joff] = (P_A + 2*P_B + P_C + 2) / 4;
    img->mpr[3+ioff][0+joff] = (P_B + 2*P_C + P_D + 2) / 4;
    break;

  case DIAG_DOWN_LEFT_PRED:
    img->mpr[0+ioff][0+joff] = (P_A + P_C + 2*(P_B) + 2) / 4;
    img->mpr[1+ioff][0+joff] = 
    img->mpr[0+ioff][1+joff] = (P_B + P_D + 2*(P_C) + 2) / 4;
    img->mpr[2+ioff][0+joff] =
    img->mpr[1+ioff][1+joff] =
    img->mpr[0+ioff][2+joff] = (P_C + P_E + 2*(P_D) + 2) / 4;
    img->mpr[3+ioff][0+joff] = 
    img->mpr[2+ioff][1+joff] = 
    img->mpr[1+ioff][2+joff] = 
    img->mpr[0+ioff][3+joff] = (P_D + P_F + 2*(P_E) + 2) / 4;
    img->mpr[3+ioff][1+joff] = 
    img->mpr[2+ioff][2+joff] = 
    img->mpr[1+ioff][3+joff] = (P_E + P_G + 2*(P_F) + 2) / 4;
    img->mpr[3+ioff][2+joff] = 
    img->mpr[2+ioff][3+joff] = (P_F + P_H + 2*(P_G) + 2) / 4;
    img->mpr[3+ioff][3+joff] = (P_G + 3*(P_H) + 2) / 4;