cabac.c

来自「JM 11.0 KTA 2.1 Source Code」· C语言 代码 · 共 1,962 行 · 第 1/5 页

* \brief
*    This function is used to arithmetically encode the mb_skip_flag.
***************************************************************************
*/
void writeMB_skip_flagInfo_CABAC(SyntaxElement *se, EncodingEnvironmentPtr eep_dp)
{
  int a,b,act_ctx;
  int bframe   = (img->type==B_SLICE);
  MotionInfoContexts *ctx         = (img->currentSlice)->mot_ctx;
  Macroblock         *currMB      = &img->mb_data[img->current_mb_nr];
  int                curr_mb_type = se->value1;
  
  if (bframe)
  {
    if (currMB->mb_available_up == NULL)
      b = 0;
    else
      b = (currMB->mb_available_up->skip_flag==0 ? 1 : 0);
    if (currMB->mb_available_left == NULL)
      a = 0;
    else
      a = (currMB->mb_available_left->skip_flag==0 ? 1 : 0);
    
    act_ctx = 7 + a + b;

    if (se->value1==0 && se->value2==0) // DIRECT mode, no coefficients
      biari_encode_symbol (eep_dp, 1, &ctx->mb_type_contexts[2][act_ctx]);
    else
      biari_encode_symbol (eep_dp, 0, &ctx->mb_type_contexts[2][act_ctx]);   

    currMB->skip_flag = (se->value1==0 && se->value2==0)?1:0;
  }
  else
  {
    if (currMB->mb_available_up == NULL)
      b = 0;
    else
      b = (( (currMB->mb_available_up)->skip_flag == 0) ? 1 : 0 );
    if (currMB->mb_available_left == NULL)
      a = 0;
    else
      a = (( (currMB->mb_available_left)->skip_flag == 0) ? 1 : 0 );

    act_ctx = a + b;

    if (curr_mb_type==0) // SKIP
      biari_encode_symbol(eep_dp, 1,&ctx->mb_type_contexts[1][act_ctx]);
    else
      biari_encode_symbol(eep_dp, 0,&ctx->mb_type_contexts[1][act_ctx]);

    currMB->skip_flag = (curr_mb_type==0)?1:0;
  }
  se->context = act_ctx;

  return;
}

/*!
***************************************************************************
* \brief
*    This function is used to arithmetically encode the macroblock
*    intra_pred_size flag info of a given MB.
***************************************************************************
*/

void writeMB_transform_size_CABAC(SyntaxElement *se, EncodingEnvironmentPtr eep_dp)
{
  int a, b;
  int act_ctx = 0;
  int act_sym;
  
  MotionInfoContexts *ctx         = (img->currentSlice)->mot_ctx;
  Macroblock         *currMB      = &img->mb_data[img->current_mb_nr];
  
  
  b = (currMB->mb_available_up == NULL) ? 0 : currMB->mb_available_up->luma_transform_size_8x8_flag;
  a = (currMB->mb_available_left == NULL) ? 0 :currMB->mb_available_left->luma_transform_size_8x8_flag;
    
  act_ctx     = a + b;
  act_sym     = currMB->luma_transform_size_8x8_flag;
  se->context = act_ctx; // store context
  biari_encode_symbol(eep_dp, (signed short) (act_sym != 0), ctx->transform_size_contexts + act_ctx );  
}

/*!
 ***************************************************************************
 * \brief
 *    This function is used to arithmetically encode the macroblock
 *    type info of a given MB.
 ***************************************************************************
 */

void writeMB_typeInfo_CABAC(SyntaxElement *se, EncodingEnvironmentPtr eep_dp)
{
  int a, b;
  int act_ctx = 0;
  int act_sym;
  signed short csym;
  int bframe   = (img->type==B_SLICE);
  int mode_sym = 0;
  int mode16x16;


  MotionInfoContexts *ctx         = (img->currentSlice)->mot_ctx;
  Macroblock         *currMB      = &img->mb_data[img->current_mb_nr];
  int                curr_mb_type = se->value1;

  if(img->type == I_SLICE)  // INTRA-frame
  {
    if (currMB->mb_available_up == NULL)
      b = 0;
    else 
      b = ((currMB->mb_available_up->mb_type != I4MB &&  currMB->mb_available_up->mb_type != I8MB) ? 1 : 0 );

    if (currMB->mb_available_left == NULL)
      a = 0;
    else 
      a = ((currMB->mb_available_left->mb_type != I4MB &&  currMB->mb_available_left->mb_type != I8MB) ? 1 : 0 );
    
    act_ctx     = a + b;
    act_sym     = curr_mb_type;
    se->context = act_ctx; // store context

    if (act_sym==0) // 4x4 Intra
    {
      biari_encode_symbol(eep_dp, 0, ctx->mb_type_contexts[0] + act_ctx );
    }
    else if( act_sym == 25 ) // PCM-MODE
    {
      biari_encode_symbol(eep_dp, 1, ctx->mb_type_contexts[0] + act_ctx );
      biari_encode_symbol_final(eep_dp, 1);
    }
    else // 16x16 Intra
    {
      biari_encode_symbol(eep_dp, 1, ctx->mb_type_contexts[0] + act_ctx );

      biari_encode_symbol_final(eep_dp, 0);

      mode_sym = act_sym-1; // Values in the range of 0...23
      act_ctx  = 4;
      act_sym  = mode_sym/12;
      biari_encode_symbol(eep_dp, (signed short) act_sym, ctx->mb_type_contexts[0] + act_ctx ); // coding of AC/no AC
      mode_sym = mode_sym % 12;
      act_sym  = mode_sym / 4; // coding of cbp: 0,1,2
      act_ctx  = 5;
      if (act_sym==0)
      {
        biari_encode_symbol(eep_dp, 0, ctx->mb_type_contexts[0] + act_ctx );
      }
      else
      {
        biari_encode_symbol(eep_dp, 1, ctx->mb_type_contexts[0] + act_ctx );
        act_ctx=6;
        biari_encode_symbol(eep_dp, (signed short) (act_sym!=1), ctx->mb_type_contexts[0] + act_ctx );
      }
      mode_sym = mode_sym & 0x03; // coding of I pred-mode: 0,1,2,3
      act_sym  = mode_sym >> 1;
      act_ctx  = 7;
      biari_encode_symbol(eep_dp, (signed short) act_sym, ctx->mb_type_contexts[0] + act_ctx );
      act_ctx  = 8;
      act_sym  = mode_sym & 0x01;
      biari_encode_symbol(eep_dp, (signed short) act_sym, ctx->mb_type_contexts[0] + act_ctx );
    }
  }
  else // INTER
  {
    
    if (bframe)
    {
      if (currMB->mb_available_up == NULL)
        b = 0;
      else
        b = ((currMB->mb_available_up->mb_type != 0) ? 1 : 0 );

      if (currMB->mb_available_left == NULL)
        a = 0;
      else
        a = ((currMB->mb_available_left->mb_type != 0) ? 1 : 0 );
      act_ctx = a + b;
      se->context = act_ctx; // store context
    }
    act_sym = curr_mb_type;

    if (act_sym>=(mode16x16=(bframe?24:7)))
    {
      mode_sym = act_sym-mode16x16;
      act_sym  = mode16x16; // 16x16 mode info
    }

    if (!bframe)
    {
      switch (act_sym)
      {
      case 0:
        break;
      case 1:
        biari_encode_symbol (eep_dp, 0, &ctx->mb_type_contexts[1][4]);
        biari_encode_symbol (eep_dp, 0, &ctx->mb_type_contexts[1][5]);
        biari_encode_symbol (eep_dp, 0, &ctx->mb_type_contexts[1][6]);
        break;
      case 2:
        biari_encode_symbol (eep_dp, 0, &ctx->mb_type_contexts[1][4]);
        biari_encode_symbol (eep_dp, 1, &ctx->mb_type_contexts[1][5]);
        biari_encode_symbol (eep_dp, 1, &ctx->mb_type_contexts[1][7]);
        break;
      case 3:
        biari_encode_symbol (eep_dp, 0, &ctx->mb_type_contexts[1][4]);
        biari_encode_symbol (eep_dp, 1, &ctx->mb_type_contexts[1][5]);
        biari_encode_symbol (eep_dp, 0, &ctx->mb_type_contexts[1][7]);
        break;
      case 4:
      case 5:
        biari_encode_symbol (eep_dp, 0, &ctx->mb_type_contexts[1][4]);
        biari_encode_symbol (eep_dp, 0, &ctx->mb_type_contexts[1][5]);
        biari_encode_symbol (eep_dp, 1, &ctx->mb_type_contexts[1][6]);
        break;
      case 6:
        biari_encode_symbol (eep_dp, 1, &ctx->mb_type_contexts[1][4]);
        biari_encode_symbol (eep_dp, 0, &ctx->mb_type_contexts[1][7]);
        break;
      case 7:
        biari_encode_symbol (eep_dp, 1, &ctx->mb_type_contexts[1][4]);
        biari_encode_symbol (eep_dp, 1, &ctx->mb_type_contexts[1][7]);
        break;
      default:
        printf ("Unsupported MB-MODE in writeMB_typeInfo_CABAC!\n");
        exit (1);
      }
    }
    else //===== B-FRAMES =====
    {
      if (act_sym==0)
      {
        biari_encode_symbol (eep_dp, 0, &ctx->mb_type_contexts[2][act_ctx]);
      }
      else if (act_sym<=2)
      {
        biari_encode_symbol (eep_dp, 1, &ctx->mb_type_contexts[2][act_ctx]);
        biari_encode_symbol (eep_dp, 0, &ctx->mb_type_contexts[2][4]);
        csym = (act_sym-1 != 0);
        biari_encode_symbol (eep_dp, csym, &ctx->mb_type_contexts[2][6]);
      }
      else if (act_sym<=10)
      {
        biari_encode_symbol (eep_dp, 1, &ctx->mb_type_contexts[2][act_ctx]);
        biari_encode_symbol (eep_dp, 1, &ctx->mb_type_contexts[2][4]);
        biari_encode_symbol (eep_dp, 0, &ctx->mb_type_contexts[2][5]);
        csym=(((act_sym-3)>>2)&0x01) != 0;
        biari_encode_symbol (eep_dp, csym, &ctx->mb_type_contexts[2][6]);
        csym=(((act_sym-3)>>1)&0x01) != 0;
        biari_encode_symbol (eep_dp, csym, &ctx->mb_type_contexts[2][6]);
        csym=((act_sym-3)&0x01) != 0;
        biari_encode_symbol (eep_dp, csym, &ctx->mb_type_contexts[2][6]);
      }
      else if (act_sym==11 || act_sym==22)
      {
        biari_encode_symbol (eep_dp, 1, &ctx->mb_type_contexts[2][act_ctx]);
        biari_encode_symbol (eep_dp, 1, &ctx->mb_type_contexts[2][4]);
        biari_encode_symbol (eep_dp, 1, &ctx->mb_type_contexts[2][5]);
        biari_encode_symbol (eep_dp, 1, &ctx->mb_type_contexts[2][6]);
        biari_encode_symbol (eep_dp, 1, &ctx->mb_type_contexts[2][6]);
        csym = (act_sym != 11);
        biari_encode_symbol (eep_dp, csym, &ctx->mb_type_contexts[2][6]);
      }
      else
      {
        if (act_sym > 22) act_sym--;
        biari_encode_symbol (eep_dp, 1, &ctx->mb_type_contexts[2][act_ctx]);
        biari_encode_symbol (eep_dp, 1, &ctx->mb_type_contexts[2][4]);
        biari_encode_symbol (eep_dp, 1, &ctx->mb_type_contexts[2][5]);
        csym=(((act_sym-12)>>3)&0x01) != 0;
        biari_encode_symbol (eep_dp, csym, &ctx->mb_type_contexts[2][6]);
        csym=(((act_sym-12)>>2)&0x01) != 0;
        biari_encode_symbol (eep_dp, csym, &ctx->mb_type_contexts[2][6]);
        csym=(((act_sym-12)>>1)&0x01) != 0;
        biari_encode_symbol (eep_dp, csym, &ctx->mb_type_contexts[2][6]);
        csym=((act_sym-12)&0x01) != 0;
        biari_encode_symbol (eep_dp, csym, &ctx->mb_type_contexts[2][6]);         
        if (act_sym >=22) act_sym++;
      }
    }

    if(act_sym==mode16x16) // additional info for 16x16 Intra-mode
    {
      if( mode_sym==25 )
      {
        biari_encode_symbol_final(eep_dp, 1 );
        return;
      }
      biari_encode_symbol_final(eep_dp, 0 );

      act_ctx = 8;
      act_sym = mode_sym/12;
      biari_encode_symbol(eep_dp, (signed short) act_sym, ctx->mb_type_contexts[1] + act_ctx ); // coding of AC/no AC
      mode_sym = mode_sym % 12;

      act_sym = mode_sym / 4; // coding of cbp: 0,1,2
      act_ctx = 9;
      if (act_sym==0)
      {
        biari_encode_symbol(eep_dp, 0, ctx->mb_type_contexts[1] + act_ctx );
      }
      else
      {
        biari_encode_symbol(eep_dp, 1, ctx->mb_type_contexts[1] + act_ctx );
        biari_encode_symbol(eep_dp, (signed short) (act_sym!=1), ctx->mb_type_contexts[1] + act_ctx );
      }

      mode_sym = mode_sym % 4; // coding of I pred-mode: 0,1,2,3
      act_ctx  = 10;
      act_sym  = mode_sym/2;
      biari_encode_symbol(eep_dp, (signed short) act_sym, ctx->mb_type_contexts[1] + act_ctx );
      act_sym  = mode_sym%2;
      biari_encode_symbol(eep_dp, (signed short) act_sym, ctx->mb_type_contexts[1] + act_ctx );
    }
  }
}


/*!
 ***************************************************************************
 * \brief
 *    This function is used to arithmetically encode the 8x8 block
 *    type info
 ***************************************************************************
 */
void writeB8_typeInfo_CABAC(SyntaxElement *se, EncodingEnvironmentPtr eep_dp)
{
  int act_ctx;
  int act_sym;
  signed short csym;
  int bframe=(img->type==B_SLICE);

  MotionInfoContexts *ctx = (img->currentSlice)->mot_ctx;

  act_sym = se->value1;
  act_ctx = 0;

  if (!bframe)  
  {
    switch (act_sym)
    {
    case 0:
      biari_encode_symbol (eep_dp, 1, &ctx->b8_type_contexts[0][1]);
      break;
    case 1:
      biari_encode_symbol (eep_dp, 0, &ctx->b8_type_contexts[0][1]);
      biari_encode_symbol (eep_dp, 0, &ctx->b8_type_contexts[0][3]);
      break;
    case 2:
      biari_encode_symbol (eep_dp, 0, &ctx->b8_type_contexts[0][1]);
      biari_encode_symbol (eep_dp, 1, &ctx->b8_type_contexts[0][3]);
      biari_encode_symbol (eep_dp, 1, &ctx->b8_type_contexts[0][4]);
      break;
    case 3:
      biari_encode_symbol (eep_dp, 0, &ctx->b8_type_contexts[0][1]);
      biari_encode_symbol (eep_dp, 1, &ctx->b8_type_contexts[0][3]);
      biari_encode_symbol (eep_dp, 0, &ctx->b8_type_contexts[0][4]);
      break;
    }
  }
  else //===== B-FRAME =====
  {
    if (act_sym==0)
    {
      biari_encode_symbol (eep_dp, 0, &ctx->b8_type_contexts[1][0]);
      return;
    }
    else
    {
      biari_encode_symbol (eep_dp, 1, &ctx->b8_type_contexts[1][0]);
      act_sym--;
    }
    if (act_sym<2)
    {
      biari_encode_symbol (eep_dp, 0, &ctx->b8_type_contexts[1][1]);
      biari_encode_symbol (eep_dp, (signed short) (act_sym!=0), &ctx->b8_type_contexts[1][3]);
    }
    else if (act_sym<6)
    {
      biari_encode_symbol (eep_dp, 1, &ctx->b8_type_contexts[1][1]);
      biari_encode_symbol (eep_dp, 0, &ctx->b8_type_contexts[1][2]);
      csym=(((act_sym-2)>>1)&0x01) != 0;
      biari_encode_symbol (eep_dp, csym, &ctx->b8_type_contexts[1][3]);
      csym=((act_sym-2)&0x01) != 0;
      biari_encode_symbol (eep_dp, csym, &ctx->b8_type_contexts[1][3]);
    }
    else
    {
      biari_encode_symbol (eep_dp, 1, &ctx->b8_type_contexts[1][1]);
      biari_encode_symbol (eep_dp, 1, &ctx->b8_type_contexts[1][2]);
      csym=(((act_sym-6)>>2)&0x01);
      if (csym)