cabac.c

H.264编码解码器源码(c语言).zip

          if (biari_decode_symbol (dep_dp, &ctx->b8_type_contexts[1][3])) act_sym+=2;
          if (biari_decode_symbol (dep_dp, &ctx->b8_type_contexts[1][3])) act_sym+=1;
        }
      }
      else
      {
        if (biari_decode_symbol (dep_dp, &ctx->b8_type_contexts[1][3])) act_sym = 1;
        else                                                            act_sym = 0;
      }
      act_sym++;
    }
    else
    {
      act_sym= 0;
    }
  }
  se->value1 = act_sym;

#if TRACE
  fprintf(p_trace, "@%d %s\t\t%d\n",symbolCount++, se->tracestring, se->value1);
  fflush(p_trace);
#endif
}

/*!
 ************************************************************************
 * \brief
 *    This function is used to arithmetically decode the macroblock
 *    type info of a given MB.
 ************************************************************************
 */
void readMB_skip_flagInfo_CABAC( SyntaxElement *se,
                                 struct inp_par *inp,
                                 struct img_par *img,
                                 DecodingEnvironmentPtr dep_dp)
{
  int a, b;
  int act_ctx;
  int bframe=(img->type==B_SLICE);
  MotionInfoContexts *ctx = (img->currentSlice)->mot_ctx;
  Macroblock *currMB = &img->mb_data[img->current_mb_nr];


  if (bframe)
  {
    if (currMB->mb_available_up == NULL)
      b = 0;
    else
      b = (currMB->mb_available_up->mb_type==0 && currMB->mb_available_up->cbp==0 ? 0 : 1);
    if (currMB->mb_available_left == NULL)
      a = 0;
    else
      a = (currMB->mb_available_left->mb_type==0 && currMB->mb_available_left->cbp==0 ? 0 : 1);
    
    act_ctx = 7 + a + b;
    
    if (biari_decode_symbol (dep_dp, &ctx->mb_type_contexts[2][act_ctx]) == 1)
      se->value1 = se->value2 = 0;
    else
      se->value1 = se->value2 = 1;
  }
  else
  {
    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;

    if (biari_decode_symbol(dep_dp, &ctx->mb_type_contexts[1][act_ctx]) == 1)
      se->value1 = 0;
    else
      se->value1 = 1;
  }
#if TRACE
  fprintf(p_trace, "@%d %s\t\t%d\t%d %d\n",symbolCount++, se->tracestring, se->value1,a,b);
  fflush(p_trace);
#endif
  if (!se->value1)
  {
    last_dquant=0;
  }
  return;
}
/*!
 ************************************************************************
 * \brief
 *    This function is used to arithmetically decode the macroblock
 *    type info of a given MB.
 ************************************************************************
 */
void readMB_typeInfo_CABAC( SyntaxElement *se,
                            struct inp_par *inp,
                            struct img_par *img,
                            DecodingEnvironmentPtr dep_dp)
{
  int a, b;
  int act_ctx;
  int act_sym;
  int bframe=(img->type==B_SLICE);
  int mode_sym;
  int ct = 0;
  int curr_mb_type;


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

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

    act_ctx = a + b;
    act_sym = biari_decode_symbol(dep_dp, ctx->mb_type_contexts[0] + act_ctx);
    se->context = act_ctx; // store context

    if (act_sym==0) // 4x4 Intra
    {
      curr_mb_type = act_sym;
    }
    else // 16x16 Intra
    {
      mode_sym = biari_decode_final(dep_dp);
      if(mode_sym == 1)
      {
        curr_mb_type = 25;
      }
      else
      {
        act_sym = 1;
        act_ctx = 4;
        mode_sym =  biari_decode_symbol(dep_dp, ctx->mb_type_contexts[0] + act_ctx ); // decoding of AC/no AC
        act_sym += mode_sym*12;
        act_ctx = 5;
        // decoding of cbp: 0,1,2
          mode_sym =  biari_decode_symbol(dep_dp, ctx->mb_type_contexts[0] + act_ctx );
        if (mode_sym!=0)
        {
          act_ctx=6;
          mode_sym = biari_decode_symbol(dep_dp, ctx->mb_type_contexts[0] + act_ctx );
          act_sym+=4;
          if (mode_sym!=0)
              act_sym+=4;
            }
          // decoding of I pred-mode: 0,1,2,3
          act_ctx = 7;
          mode_sym =  biari_decode_symbol(dep_dp, ctx->mb_type_contexts[0] + act_ctx );
          act_sym += mode_sym*2;
          act_ctx = 8;
          mode_sym =  biari_decode_symbol(dep_dp, ctx->mb_type_contexts[0] + act_ctx );
          act_sym += mode_sym;
          curr_mb_type = act_sym;
      }
    }
  }
  else if(img->type == SI_SLICE)  // SI-frame
  {
    // special ctx's for SI4MB
    if (currMB->mb_available_up == NULL)
      b = 0;
    else 
      b = (( (currMB->mb_available_up)->mb_type != SI4MB) ? 1 : 0 );
    if (currMB->mb_available_left == NULL)
      a = 0;
    else 
      a = (( (currMB->mb_available_left)->mb_type != SI4MB) ? 1 : 0 );

    act_ctx = a + b;
    act_sym = biari_decode_symbol(dep_dp, ctx->mb_type_contexts[4] + act_ctx);
    se->context = act_ctx; // store context

    if (act_sym==0) //  SI 4x4 Intra
    {
      curr_mb_type = 0;
    }
    else // analog INTRA_IMG
    {
      if (currMB->mb_available_up == NULL)
        b = 0;
      else 
        b = (( (currMB->mb_available_up)->mb_type != I4MB) ? 1 : 0 );
      if (currMB->mb_available_left == NULL)
        a = 0;
      else 
        a = (( (currMB->mb_available_left)->mb_type != I4MB) ? 1 : 0 );

      act_ctx = a + b;
      act_sym = biari_decode_symbol(dep_dp, ctx->mb_type_contexts[0] + act_ctx);
      se->context = act_ctx; // store context
      
      
      if (act_sym==0) // 4x4 Intra
      {
        curr_mb_type = 1;
      }
      else // 16x16 Intra
      {
        mode_sym = biari_decode_final(dep_dp);
        if( mode_sym==1 )
        {
          curr_mb_type = 26;
        }
        else
        {
          act_sym = 2;
          act_ctx = 4;
          mode_sym =  biari_decode_symbol(dep_dp, ctx->mb_type_contexts[0] + act_ctx ); // decoding of AC/no AC
          act_sym += mode_sym*12;
          act_ctx = 5;
          // decoding of cbp: 0,1,2
          mode_sym =  biari_decode_symbol(dep_dp, ctx->mb_type_contexts[0] + act_ctx );
          if (mode_sym!=0)
          {
            act_ctx=6;
            mode_sym = biari_decode_symbol(dep_dp, ctx->mb_type_contexts[0] + act_ctx );
            act_sym+=4;
            if (mode_sym!=0)
              act_sym+=4;
          }
          // decoding of I pred-mode: 0,1,2,3
          act_ctx = 7;
          mode_sym =  biari_decode_symbol(dep_dp, ctx->mb_type_contexts[0] + act_ctx );
          act_sym += mode_sym*2;
          act_ctx = 8;
          mode_sym =  biari_decode_symbol(dep_dp, ctx->mb_type_contexts[0] + act_ctx );
          act_sym += mode_sym;
          curr_mb_type = act_sym;
        }
      }
    }
  }
  else
  {
    if (bframe)
    {
      ct = 1;
      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;

      if (biari_decode_symbol (dep_dp, &ctx->mb_type_contexts[2][act_ctx]))
      {
        if (biari_decode_symbol (dep_dp, &ctx->mb_type_contexts[2][4]))
        {
          if (biari_decode_symbol (dep_dp, &ctx->mb_type_contexts[2][5]))
          {
            act_sym=12;
            if (biari_decode_symbol (dep_dp, &ctx->mb_type_contexts[2][6])) act_sym+=8;
            if (biari_decode_symbol (dep_dp, &ctx->mb_type_contexts[2][6])) act_sym+=4;
            if (biari_decode_symbol (dep_dp, &ctx->mb_type_contexts[2][6])) act_sym+=2;

            if      (act_sym==24)  act_sym=11;
            else if (act_sym==26)  act_sym=22;
            else
            {
              if (act_sym==22)     act_sym=23;
              if (biari_decode_symbol (dep_dp, &ctx->mb_type_contexts[2][6])) act_sym+=1; 
            }
          }
          else
          {
            act_sym=3;
            if (biari_decode_symbol (dep_dp, &ctx->mb_type_contexts[2][6])) act_sym+=4;
            if (biari_decode_symbol (dep_dp, &ctx->mb_type_contexts[2][6])) act_sym+=2;
            if (biari_decode_symbol (dep_dp, &ctx->mb_type_contexts[2][6])) act_sym+=1;
          }
        }
        else
        {
          if (biari_decode_symbol (dep_dp, &ctx->mb_type_contexts[2][6])) act_sym=2;
          else                                                            act_sym=1;
        }
      }
      else
      {
        act_sym = 0;
      }
    }
    else // P-frame
    {
      {
        if (biari_decode_symbol(dep_dp, &ctx->mb_type_contexts[1][4] )) 
        {
          if (biari_decode_symbol(dep_dp, &ctx->mb_type_contexts[1][7] ))   act_sym = 7;
          else                                                              act_sym = 6;
        }
        else
        {
          if (biari_decode_symbol(dep_dp, &ctx->mb_type_contexts[1][5] ))
          {
            if (biari_decode_symbol(dep_dp, &ctx->mb_type_contexts[1][7] )) act_sym = 2;
            else                                                            act_sym = 3;
          }
          else
          {
            if (biari_decode_symbol(dep_dp, &ctx->mb_type_contexts[1][6] )) act_sym = 4;
            else                                                            act_sym = 1;
          }
        }
      }
    }

    if (act_sym<=6 || (((img->type == B_SLICE)?1:0) && act_sym<=23))
    {
      curr_mb_type = act_sym;
    }
    else  // additional info for 16x16 Intra-mode
    {
      mode_sym = biari_decode_final(dep_dp);
      if( mode_sym==1 )
      {
        curr_mb_type = act_sym + 25;
      }
      else
      {
        act_ctx = 8;
        mode_sym =  biari_decode_symbol(dep_dp, ctx->mb_type_contexts[1] + act_ctx ); // decoding of AC/no AC
        act_sym += mode_sym*12;

        // decoding of cbp: 0,1,2
        act_ctx = 9;
        mode_sym = biari_decode_symbol(dep_dp, ctx->mb_type_contexts[1] + act_ctx );
        if (mode_sym != 0)
        {
          act_sym+=4;
          mode_sym = biari_decode_symbol(dep_dp, ctx->mb_type_contexts[1] + act_ctx );
          if (mode_sym != 0)
            act_sym+=4;
        }

        // decoding of I pred-mode: 0,1,2,3
        act_ctx = 10;
        mode_sym = biari_decode_symbol(dep_dp, ctx->mb_type_contexts[1] + act_ctx );
        act_sym += mode_sym*2;
        mode_sym = biari_decode_symbol(dep_dp, ctx->mb_type_contexts[1] + act_ctx );
        act_sym += mode_sym;
        curr_mb_type = act_sym;
      }
    }
  }
  se->value1 = curr_mb_type;

//	if (curr_mb_type >= 23)				printf(" stopx");
#if TRACE
  fprintf(p_trace, "@%d %s\t\t\t%d\n",symbolCount++, se->tracestring, se->value1);
  fflush(p_trace);
#endif
}

/*!
 ************************************************************************
 * \brief
 *    This function is used to arithmetically decode a pair of
 *    intra prediction modes of a given MB.
 ************************************************************************
 */
void readIntraPredMode_CABAC( SyntaxElement *se,
                              struct inp_par *inp,
                              struct img_par *img,
                              DecodingEnvironmentPtr dep_dp)
{
  TextureInfoContexts *ctx     = img->currentSlice->tex_ctx;
	int act_sym;

	// use_most_probable_mode
	act_sym = biari_decode_symbol(dep_dp, ctx->ipr_contexts);

	// remaining_mode_selector
	if (act_sym == 1)
		se->value1 = -1;
	else
	{
		se->value1  = 0;
		se->value1 |= (biari_decode_symbol(dep_dp, ctx->ipr_contexts+1)     );
		se->value1 |= (biari_decode_symbol(dep_dp, ctx->ipr_contexts+1) << 1);
		se->value1 |= (biari_decode_symbol(dep_dp, ctx->ipr_contexts+1) << 2);
	}

#if TRACE
  fprintf(p_trace, "@%d %s\t\t\t%d\n",symbolCount++, se->tracestring, se->value1);
  fflush(p_trace);
#endif
}
/*!
 ************************************************************************
 * \brief
 *    This function is used to arithmetically decode the reference
 *    parameter of a given MB.
 ************************************************************************
 */
void readRefFrame_CABAC( SyntaxElement *se,
                         struct inp_par *inp,
                         struct img_par *img,
                         DecodingEnvironmentPtr dep_dp)
{