cabac.c

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#include "global.h"
#include "cabac.h"
#include "memalloc.h"
#include "elements.h"
#include "image.h"
#include "biaridecod.h"
#include "mb_access.h"
#include "vlc.h"

#if TRACE
int symbolCount = 0;
#endif

/***********************************************************************
 * L O C A L L Y   D E F I N E D   F U N C T I O N   P R O T O T Y P E S
 ***********************************************************************
 */
static unsigned int unary_bin_decode(DecodingEnvironmentPtr dep_dp,
                                     BiContextTypePtr ctx,
                                     int ctx_offset);
static unsigned int unary_bin_max_decode(DecodingEnvironmentPtr dep_dp,
                                         BiContextTypePtr ctx,
                                         int ctx_offset,
                                         unsigned int max_symbol);
static unsigned int unary_exp_golomb_level_decode( DecodingEnvironmentPtr dep_dp,
                                                  BiContextTypePtr ctx);
static unsigned int unary_exp_golomb_mv_decode(DecodingEnvironmentPtr dep_dp,
                                               BiContextTypePtr ctx,
                                               unsigned int max_bin);

void CheckAvailabilityOfNeighborsCABAC(Macroblock *currMB)
{
  ImageParameters *p_Img = currMB->p_Img;
  PixelPos up, left;
  int *mb_size = p_Img->mb_size[IS_LUMA];

  p_Img->getNeighbour(currMB, -1,  0, mb_size, &left);
  p_Img->getNeighbour(currMB,  0, -1, mb_size, &up);

  if (up.available)
    currMB->mb_up = &p_Img->mb_data[up.mb_addr];
  else
    currMB->mb_up = NULL;

  if (left.available)
    currMB->mb_left = &p_Img->mb_data[left.mb_addr];
  else
    currMB->mb_left = NULL;
}

void cabac_new_slice(Slice *currSlice)
{
  currSlice->last_dquant=0;
}

MotionInfoContexts* create_contexts_MotionInfo(void)
{
  MotionInfoContexts *deco_ctx;

  deco_ctx = (MotionInfoContexts*) calloc(1, sizeof(MotionInfoContexts) );
  if( deco_ctx == NULL )
    no_mem_exit("create_contexts_MotionInfo: deco_ctx");

  return deco_ctx;
}


TextureInfoContexts* create_contexts_TextureInfo(void)
{
  TextureInfoContexts *deco_ctx;

  deco_ctx = (TextureInfoContexts*) calloc(1, sizeof(TextureInfoContexts) );
  if( deco_ctx == NULL )
    no_mem_exit("create_contexts_TextureInfo: deco_ctx");

  return deco_ctx;
}


void delete_contexts_MotionInfo(MotionInfoContexts *deco_ctx)
{
  if( deco_ctx == NULL )
    return;

  free( deco_ctx );
}


void delete_contexts_TextureInfo(TextureInfoContexts *deco_ctx)
{
  if( deco_ctx == NULL )
    return;

  free( deco_ctx );
}

void readFieldModeInfo_CABAC(Macroblock *currMB,  
                             SyntaxElement *se,
                             DecodingEnvironmentPtr dep_dp)
{  
  Slice *currSlice = currMB->p_Slice;
  ImageParameters *p_Img = currMB->p_Img;
  MotionInfoContexts *ctx  = currSlice->mot_ctx;
  int a = currMB->mbAvailA ? p_Img->mb_data[currMB->mbAddrA].mb_field : 0;
  int b = currMB->mbAvailB ? p_Img->mb_data[currMB->mbAddrB].mb_field : 0;
  int act_ctx = a + b;

  se->value1 = biari_decode_symbol (dep_dp, &ctx->mb_aff_contexts[act_ctx]);

#if TRACE
  fprintf(p_Dec->p_trace, "@%-6d %-63s (%3d)\n",symbolCount++, se->tracestring, se->value1);
  fflush(p_Dec->p_trace);
#endif
}


int check_next_mb_and_get_field_mode_CABAC( Slice *currSlice,
                                           SyntaxElement *se,                                           
                                           DataPartition  *act_dp)
{
  ImageParameters *p_Img = currSlice->p_Img;
  BiContextTypePtr          mb_type_ctx_copy[3];
  BiContextTypePtr          mb_aff_ctx_copy;
  DecodingEnvironmentPtr    dep_dp_copy;

  int length;
  DecodingEnvironmentPtr    dep_dp = &(act_dp->de_cabac);

  int bframe = (currSlice->slice_type == B_SLICE);
  int skip   = 0;
  int field  = 0;
  int i;

  Macroblock *currMB;

  //get next MB
  ++p_Img->current_mb_nr;

  currMB = &p_Img->mb_data[p_Img->current_mb_nr];
  currMB->p_Img    = p_Img;
  currMB->p_Slice  = currSlice; 
  currMB->slice_nr = p_Img->current_slice_nr;
  currMB->mb_field = p_Img->mb_data[p_Img->current_mb_nr-1].mb_field;
  currMB->mbAddrX  = p_Img->current_mb_nr;

  CheckAvailabilityOfNeighbors(currMB);
  CheckAvailabilityOfNeighborsCABAC(currMB);

  //create
  dep_dp_copy = (DecodingEnvironmentPtr) calloc(1, sizeof(DecodingEnvironment) );
  for (i=0;i<3;++i)
    mb_type_ctx_copy[i] = (BiContextTypePtr) calloc(NUM_MB_TYPE_CTX, sizeof(BiContextType) );
  mb_aff_ctx_copy = (BiContextTypePtr) calloc(NUM_MB_AFF_CTX, sizeof(BiContextType) );

  //copy
  memcpy(dep_dp_copy,dep_dp,sizeof(DecodingEnvironment));
  length = *(dep_dp_copy->Dcodestrm_len) = *(dep_dp->Dcodestrm_len);
  for (i=0;i<3;++i)
    memcpy(mb_type_ctx_copy[i], currSlice->mot_ctx->mb_type_contexts[i],NUM_MB_TYPE_CTX*sizeof(BiContextType) );
  memcpy(mb_aff_ctx_copy, currSlice->mot_ctx->mb_aff_contexts,NUM_MB_AFF_CTX*sizeof(BiContextType) );

  //check_next_mb
#if TRACE
  strncpy(se->tracestring, "mb_skip_flag (of following bottom MB)", TRACESTRING_SIZE);
#endif
  currSlice->last_dquant = 0;
  readMB_skip_flagInfo_CABAC(currMB, se, dep_dp);

  skip = (bframe)? (se->value1==0 && se->value2==0) : (se->value1==0);
  if (!skip)
  {
#if TRACE
    strncpy(se->tracestring, "mb_field_decoding_flag (of following bottom MB)", TRACESTRING_SIZE);
#endif
    readFieldModeInfo_CABAC( currMB, se,dep_dp);
    field = se->value1;
    p_Img->mb_data[p_Img->current_mb_nr-1].mb_field = field;
  }

  //reset
  p_Img->current_mb_nr--;

  memcpy(dep_dp,dep_dp_copy,sizeof(DecodingEnvironment));
  *(dep_dp->Dcodestrm_len) = length;
  for (i=0;i<3;++i)
    memcpy(currSlice->mot_ctx->mb_type_contexts[i],mb_type_ctx_copy[i], NUM_MB_TYPE_CTX*sizeof(BiContextType) );
  memcpy( currSlice->mot_ctx->mb_aff_contexts,mb_aff_ctx_copy,NUM_MB_AFF_CTX*sizeof(BiContextType) );

  CheckAvailabilityOfNeighborsCABAC(currMB);

  //delete
  free(dep_dp_copy);
  for (i=0;i<3;++i)
    free(mb_type_ctx_copy[i]);
  free(mb_aff_ctx_copy);

  return skip;
}




void readMVD_CABAC( Macroblock *currMB, 
                   SyntaxElement *se,
                   DecodingEnvironmentPtr dep_dp)
{
  ImageParameters *p_Img = currMB->p_Img;
  Slice *currSlice = currMB->p_Slice;
  MotionInfoContexts *ctx = currSlice->mot_ctx;
  int i = currMB->subblock_x;
  int j = currMB->subblock_y;
  int a = 0, b = 0;
  int act_ctx;
  int act_sym;
  int mv_local_err;
  int list_idx = se->value2 & 0x01;
  int k = (se->value2 >> 1); // MVD component

  PixelPos block_a, block_b;

  get4x4Neighbour(currMB, i - 1, j    , p_Img->mb_size[IS_LUMA], &block_a);
  get4x4Neighbour(currMB, i,     j - 1, p_Img->mb_size[IS_LUMA], &block_b);

  if (block_b.available)
  {
    b = iabs(p_Img->mb_data[block_b.mb_addr].mvd[list_idx][block_b.y][block_b.x][k]);
    if (currSlice->MbaffFrameFlag && (k==1))
    {
      if ((currMB->mb_field==0) && (p_Img->mb_data[block_b.mb_addr].mb_field==1))
        b *= 2;
      else if ((currMB->mb_field==1) && (p_Img->mb_data[block_b.mb_addr].mb_field==0))
        b /= 2;
    }
  }

  if (block_a.available)
  {
    a = iabs(p_Img->mb_data[block_a.mb_addr].mvd[list_idx][block_a.y][block_a.x][k]);
    if (currSlice->MbaffFrameFlag && (k==1))
    {
      if ((currMB->mb_field==0) && (p_Img->mb_data[block_a.mb_addr].mb_field==1))
        a *= 2;
      else if ((currMB->mb_field==1) && (p_Img->mb_data[block_a.mb_addr].mb_field==0))
        a /= 2;
    }
  }

  if ((mv_local_err = a + b)<3)
    act_ctx = 5*k;
  else
  {
    if (mv_local_err > 32)
      act_ctx = 5*k+3;
    else
      act_ctx = 5*k+2;
  }

  se->context = act_ctx;

  act_sym = biari_decode_symbol(dep_dp,&ctx->mv_res_contexts[0][act_ctx] );

  if (act_sym != 0)
  {
    int mv_sign;
    act_ctx = 5 * k;
    act_sym = unary_exp_golomb_mv_decode(dep_dp,ctx->mv_res_contexts[1]+act_ctx,3);
    ++act_sym;
    mv_sign = biari_decode_symbol_eq_prob(dep_dp);

    if(mv_sign)
      act_sym = -act_sym;
  }
  se->value1 = act_sym;

#if TRACE
  fprintf(p_Dec->p_trace, "@%-6d %-63s (%3d)\n",symbolCount++, se->tracestring, se->value1);
  fflush(p_Dec->p_trace);
#endif
}


void readB8_typeInfo_CABAC (Macroblock *currMB, 
                            SyntaxElement *se,
                            DecodingEnvironmentPtr dep_dp)
{
  Slice *currSlice = currMB->p_Slice;
  int act_sym = 0;
  int bframe  = (currSlice->slice_type == B_SLICE);

  MotionInfoContexts *ctx = currSlice->mot_ctx;


  if (!bframe)
  {
    if (biari_decode_symbol (dep_dp, &ctx->b8_type_contexts[0][1]))
    {
      act_sym = 0;
    }
    else
    {
      if (biari_decode_symbol (dep_dp, &ctx->b8_type_contexts[0][3]))
      {
        if (biari_decode_symbol (dep_dp, &ctx->b8_type_contexts[0][4])) act_sym = 2;
        else                                                            act_sym = 3;
      }
      else
      {
        act_sym = 1;
      }
    }
  }
  else
  {
    if (biari_decode_symbol (dep_dp, &ctx->b8_type_contexts[1][0]))
    {
      if (biari_decode_symbol (dep_dp, &ctx->b8_type_contexts[1][1]))
      {
        if (biari_decode_symbol (dep_dp, &ctx->b8_type_contexts[1][2]))
        {
          if (biari_decode_symbol (dep_dp, &ctx->b8_type_contexts[1][3]))
          {
            act_sym = 10;
            if (biari_decode_symbol (dep_dp, &ctx->b8_type_contexts[1][3])) act_sym++;
          }
          else
          {
            act_sym = 6;
            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++;
          }
        }
        else
        {
          act_sym=2;
          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_Dec->p_trace, "@%-6d %-63s (%3d)\n",symbolCount++, se->tracestring, se->value1);
  fflush(p_Dec->p_trace);
#endif
}

void readMB_skip_flagInfo_CABAC( Macroblock *currMB, 
                                SyntaxElement *se,
                                DecodingEnvironmentPtr dep_dp)
{  
  Slice *currSlice = currMB->p_Slice;
  int bframe=(currSlice->slice_type == B_SLICE);
  MotionInfoContexts *ctx = currSlice->mot_ctx;  
  int a = (currMB->mb_left != NULL) ? (currMB->mb_left->skip_flag == 0) : 0;
  int b = (currMB->mb_up   != NULL) ? (currMB->mb_up  ->skip_flag == 0) : 0;
  int act_ctx;

  if (bframe)
  {
    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
  {
    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_Dec->p_trace, "@%-6d %-63s (%3d)\n",symbolCount++, se->tracestring, se->value1);
  fflush(p_Dec->p_trace);
#endif
  if (!se->value1)
  {
    currSlice->last_dquant = 0;
  }
}

void readMB_transform_size_flag_CABAC( Macroblock *currMB, 
                                      SyntaxElement *se,
                                      DecodingEnvironmentPtr dep_dp)
{
  Slice *currSlice = currMB->p_Slice;
  TextureInfoContexts*ctx = currSlice->tex_ctx;

  int b = (currMB->mb_up   == NULL) ? 0 : currMB->mb_up->luma_transform_size_8x8_flag;
  int a = (currMB->mb_left == NULL) ? 0 : currMB->mb_left->luma_transform_size_8x8_flag;

  int act_ctx = a + b;
  int act_sym = biari_decode_symbol(dep_dp, ctx->transform_size_contexts + act_ctx );

  se->value1 = act_sym;

#if TRACE
  fprintf(p_Dec->p_trace, "@%-6d %-63s (%3d)\n",symbolCount++, se->tracestring, se->value1);
  fflush(p_Dec->p_trace);
#endif

}

void readMB_typeInfo_CABAC(Macroblock *currMB,  
                           SyntaxElement *se,
                           DecodingEnvironmentPtr dep_dp)
{
  Slice *currSlice = currMB->p_Slice;
  MotionInfoContexts *ctx = currSlice->mot_ctx;

  int a = 0, b = 0;
  int act_ctx;
  int act_sym;
  int bframe=(currSlice->slice_type == B_SLICE);
  int mode_sym;
  int curr_mb_type;


  if(currSlice->slice_type == I_SLICE)  // INTRA-frame
  {
    if (currMB->mb_up != NULL)
      b = (((currMB->mb_up)->mb_type != I4MB && currMB->mb_up->mb_type != I8MB) ? 1 : 0 );

    if (currMB->mb_left != NULL)
      a = (((currMB->mb_left)->mb_type != I4MB && currMB->mb_left->mb_type != I8MB) ? 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(currSlice->slice_type == SI_SLICE)  // SI-frame
  {
    // special ctx's for SI4MB
    if (currMB->mb_up != NULL)
      b = (( (currMB->mb_up)->mb_type != SI4MB) ? 1 : 0 );

    if (currMB->mb_left != NULL)
      a = (( (currMB->mb_left)->mb_type != SI4MB) ? 1 : 0 );

    act_ctx = a + b;
    act_sym = biari_decode_symbol(dep_dp, ctx->mb_type_contexts[1] + 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_up != NULL)
        b = (( (currMB->mb_up)->mb_type != I4MB) ? 1 : 0 );

      if (currMB->mb_left != NULL)
        a = (( (currMB->mb_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)
    {
      if (currMB->mb_up != NULL)
        b = (( (currMB->mb_up)->mb_type != 0) ? 1 : 0 );

      if (currMB->mb_left != NULL)
        a = (( (currMB->mb_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 || (((currSlice->slice_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 )
      {
        if(bframe)  // B frame
          curr_mb_type = 48;
        else      // P frame
          curr_mb_type = 31;
      }
      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_Dec->p_trace, "@%-6d %-63s (%3d)\n",symbolCount++, se->tracestring, se->value1);
  fflush(p_Dec->p_trace);
#endif
}

void readIntraPredMode_CABAC( Macroblock *currMB, 
                              SyntaxElement *se,
                              DecodingEnvironmentPtr dep_dp)
{
  Slice *currSlice = currMB->p_Slice;
  TextureInfoContexts *ctx     = currSlice->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_Dec->p_trace, "@%-6d %-63s (%3d)\n",symbolCount++, se->tracestring, se->value1);
  fflush(p_Dec->p_trace);
#endif
}
void readRefFrame_CABAC(Macroblock *currMB, 
                        SyntaxElement *se,
                        DecodingEnvironmentPtr dep_dp)
{
  Slice *currSlice = currMB->p_Slice;
  ImageParameters *p_Img = currMB->p_Img;
  StorablePicture *dec_picture = p_Img->dec_picture;
  MotionInfoContexts *ctx = currSlice->mot_ctx;
  Macroblock *neighborMB = NULL;

  int   addctx  = 0;
  int   a = 0, b = 0;
  int   act_ctx;
  int   act_sym;
  char** refframe_array = dec_picture->motion.ref_idx[se->value2];

  PixelPos block_a, block_b;

  get4x4Neighbour(currMB, currMB->subblock_x - 1, currMB->subblock_y    , p_Img->mb_size[IS_LUMA], &block_a);
  get4x4Neighbour(currMB, currMB->subblock_x,     currMB->subblock_y - 1, p_Img->mb_size[IS_LUMA], &block_b);

  if (block_b.available)
  {
    int b8b=((block_b.x >> 1) & 0x01)+(block_b.y & 0x02);    
    neighborMB = &p_Img->mb_data[block_b.mb_addr];
    if (!( (neighborMB->mb_type==IPCM) || IS_DIRECT(neighborMB) || (neighborMB->b8mode[b8b]==0 && neighborMB->b8pdir[b8b]==2)))
    {
      if (currSlice->MbaffFrameFlag && (currMB->mb_field == FALSE) && (neighborMB->mb_field == TRUE))
        b = (refframe_array[block_b.pos_y][block_b.pos_x] > 1 ? 2 : 0);
      else
        b = (refframe_array[block_b.pos_y][block_b.pos_x] > 0 ? 2 : 0);
    }
  }

  if (block_a.available)
  {    
    int b8a=((block_a.x >> 1) & 0x01)+(block_a.y & 0x02);    
    neighborMB = &p_Img->mb_data[block_a.mb_addr];
    if (!((neighborMB->mb_type==IPCM) || IS_DIRECT(neighborMB) || (neighborMB->b8mode[b8a]==0 && neighborMB->b8pdir[b8a]==2)))
    {
      if (currSlice->MbaffFrameFlag && (currMB->mb_field == FALSE) && (neighborMB->mb_field == 1))
        a = (refframe_array[block_a.pos_y][block_a.pos_x] > 1 ? 1 : 0);
      else
        a = (refframe_array[block_a.pos_y][block_a.pos_x] > 0 ? 1 : 0);
    }
  }

  act_ctx = a + b;
  se->context = act_ctx; // store context

  act_sym = biari_decode_symbol(dep_dp,ctx->ref_no_contexts[addctx] + act_ctx );

  if (act_sym != 0)
  {
    act_ctx = 4;
    act_sym = unary_bin_decode(dep_dp,ctx->ref_no_contexts[addctx] + act_ctx,1);
    ++act_sym;
  }
  se->value1 = act_sym;

#if TRACE
  fprintf(p_Dec->p_trace, "@%-6d %-63s (%3d)\n",symbolCount++, se->tracestring, se->value1);
//  fprintf(p_Dec->p_trace," c: %d :%d \n",ctx->ref_no_contexts[addctx][act_ctx].cum_freq[0],ctx->ref_no_contexts[addctx][act_ctx].cum_freq[1]);
  fflush(p_Dec->p_trace);
#endif
}


void readDquant_CABAC( Macroblock *currMB, 
                       SyntaxElement *se,                       
                       DecodingEnvironmentPtr dep_dp)
{
  Slice *currSlice = currMB->p_Slice;
  MotionInfoContexts *ctx = currSlice->mot_ctx;
  int *dquant = &se->value1;
  int act_ctx = ((currSlice->last_dquant != 0) ? 1 : 0);
  int act_sym = biari_decode_symbol(dep_dp,ctx->delta_qp_contexts + act_ctx );

  if (act_sym != 0)
  {
    act_ctx = 2;
    act_sym = unary_bin_decode(dep_dp,ctx->delta_qp_contexts + act_ctx,1);
    ++act_sym;
  }

  *dquant = (act_sym + 1) >> 1;
  if((act_sym & 0x01)==0)                           // lsb is signed bit
    *dquant = -*dquant;

  currSlice->last_dquant = *dquant;

#if TRACE
  fprintf(p_Dec->p_trace, "@%-6d %-63s (%3d)\n",symbolCount++, se->tracestring, se->value1);
  fflush(p_Dec->p_trace);
#endif
}
void readCBP_CABAC(Macroblock *currMB, 
                   SyntaxElement *se,
                   DecodingEnvironmentPtr dep_dp)
{
  ImageParameters *p_Img = currMB->p_Img;
  StorablePicture *dec_picture = p_Img->dec_picture;
  Slice *currSlice = currMB->p_Slice;
  TextureInfoContexts *ctx = currSlice->tex_ctx;  
  Macroblock *neighborMB = NULL;

  int mb_x, mb_y;
  int a = 0, b = 0;
  int curr_cbp_ctx;
  int cbp = 0;
  int cbp_bit;
  int mask;
  PixelPos block_a;

  //  coding of luma part (bit by bit)
  for (mb_y=0; mb_y < 4; mb_y += 2)
  {
    if (mb_y == 0)
    {
      neighborMB = currMB->mb_up;
      b = 0;
    }

    for (mb_x=0; mb_x < 4; mb_x += 2)
    {
      if (mb_y == 0)
      {
        if (neighborMB != NULL)
        {
          if(neighborMB->mb_type!=IPCM)
            b = (( (neighborMB->cbp & (1<<(2 + (mb_x>>1)))) == 0) ? 2 : 0);
        }
      }
      else
        b = ( ((cbp & (1<<(mb_x/2))) == 0) ? 2: 0);

      if (mb_x == 0)
      {
        get4x4Neighbour(currMB, (mb_x<<2) - 1, (mb_y << 2), p_Img->mb_size[IS_LUMA], &block_a);
        if (block_a.available)
        {
          if(p_Img->mb_data[block_a.mb_addr].mb_type==IPCM)
            a = 0;
          else
            a = (( (p_Img->mb_data[block_a.mb_addr].cbp & (1<<(2*(block_a.y/2)+1))) == 0) ? 1 : 0);
        }
        else
          a=0;
      }
      else
        a = ( ((cbp & (1<<mb_y)) == 0) ? 1: 0);

      curr_cbp_ctx = a + b;
      mask = (1 << (mb_y + (mb_x >> 1)));
      cbp_bit = biari_decode_symbol(dep_dp, ctx->cbp_contexts[0] + curr_cbp_ctx );
      if (cbp_bit) 
        cbp += mask;
    }
  }

  if ((dec_picture->chroma_format_idc != YUV400) && (dec_picture->chroma_format_idc != YUV444)) 
  {
    // coding of chroma part
    // CABAC decoding for BinIdx 0
    b = 0;
    neighborMB = currMB->mb_up;
    if (neighborMB != NULL)
    {
      if (neighborMB->mb_type==IPCM || (neighborMB->cbp > 15))
        b = 2;
    }

    a = 0;
    neighborMB = currMB->mb_left;
    if (neighborMB != NULL)
    {
      if (neighborMB->mb_type==IPCM || (neighborMB->cbp > 15))
        a = 1;
    }

    curr_cbp_ctx = a + b;
    cbp_bit = biari_decode_symbol(dep_dp, ctx->cbp_contexts[1] + curr_cbp_ctx );

    // CABAC decoding for BinIdx 1
    if (cbp_bit) // set the chroma bits
    {
      b = 0;
      neighborMB = currMB->mb_up;
      if (neighborMB != NULL)
      {
        //if ((neighborMB->mb_type == IPCM) || ((neighborMB->cbp > 15) && ((neighborMB->cbp >> 4) == 2)))
        if ((neighborMB->mb_type == IPCM) || ((neighborMB->cbp >> 4) == 2))
          b = 2;
      }


      a = 0;
      neighborMB = currMB->mb_left;
      if (neighborMB != NULL)
      {
        if ((neighborMB->mb_type == IPCM) || ((neighborMB->cbp >> 4) == 2))
          a = 1;
      }

      curr_cbp_ctx = a + b;
      cbp_bit = biari_decode_symbol(dep_dp, ctx->cbp_contexts[2] + curr_cbp_ctx );
      cbp += (cbp_bit == 1) ? 32 : 16;
    }
  }

  se->value1 = cbp;

  if (!cbp)
  {
    currSlice->last_dquant = 0;
  }

#if TRACE
  fprintf(p_Dec->p_trace, "@%-6d %-63s (%3d)\n",symbolCount++, se->tracestring, se->value1);
  fflush(p_Dec->p_trace);
#endif
}

void readCIPredMode_CABAC(Macroblock *currMB, 
                          SyntaxElement *se,
                          DecodingEnvironmentPtr dep_dp)
{
  Slice *currSlice = currMB->p_Slice;
  TextureInfoContexts *ctx = currSlice->tex_ctx;
  int                 *act_sym  = &se->value1;

  Macroblock          *MbUp   = currMB->mb_up;
  Macroblock          *MbLeft = currMB->mb_left;

  int b = (MbUp != NULL)   ? (((MbUp->c_ipred_mode   != 0) && (MbUp->mb_type != IPCM)) ? 1 : 0) : 0;
  int a = (MbLeft != NULL) ? (((MbLeft->c_ipred_mode != 0) && (MbLeft->mb_type != IPCM)) ? 1 : 0) : 0;
  int act_ctx = a + b;

  *act_sym = biari_decode_symbol(dep_dp, ctx->cipr_contexts + act_ctx );

  if (*act_sym != 0)
    *act_sym = unary_bin_max_decode(dep_dp, ctx->cipr_contexts + 3, 0, 1) + 1;

#if TRACE
  fprintf(p_Dec->p_trace, "@%-6d %-63s (%3d)\n",symbolCount++, se->tracestring, se->value1);
  fflush(p_Dec->p_trace);
#endif

}

static const int maxpos       [] = {15, 14, 63, 31, 31, 15,  3, 14,  7, 15, 15, 14, 63, 31, 31, 15, 15, 14, 63, 31, 31, 15};
static const int c1isdc       [] = { 1,  0,  1,  1,  1,  1,  1,  0,  1,  1,  1,  0,  1,  1,  1,  1,  1,  0,  1,  1,  1,  1};
static const int type2ctx_bcbp[] = { 0,  1,  2,  3,  3,  4,  5,  6,  5,  5, 10, 11, 12, 13, 13, 14, 16, 17, 18, 19, 19, 20};
static const int type2ctx_map [] = { 0,  1,  2,  3,  4,  5,  6,  7,  6,  6, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21}; // 8
static const int type2ctx_last[] = { 0,  1,  2,  3,  4,  5,  6,  7,  6,  6, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21}; // 8
static const int type2ctx_one [] = { 0,  1,  2,  3,  3,  4,  5,  6,  5,  5, 10, 11, 12, 13, 13, 14, 16, 17, 18, 19, 19, 20}; // 7
static const int type2ctx_abs [] = { 0,  1,  2,  3,  3,  4,  5,  6,  5,  5, 10, 11, 12, 13, 13, 14, 16, 17, 18, 19, 19, 20}; // 7
static const int max_c2       [] = { 4,  4,  4,  4,  4,  4,  3,  4,  3,  3,  4,  4,  4,  4,  4,  4,  4,  4,  4,  4,  4,  4}; // 9



int read_and_store_CBP_block_bit_444 (Macroblock              *currMB,
                                        DecodingEnvironmentPtr  dep_dp,
                                        int                     type)
{
  Slice *currSlice = currMB->p_Slice;
  ImageParameters *p_Img = currMB->p_Img;
  StorablePicture *dec_picture = p_Img->dec_picture;
  TextureInfoContexts *tex_ctx = currSlice->tex_ctx;

  int y_ac        = (type==LUMA_16AC || type==LUMA_8x8 || type==LUMA_8x4 || type==LUMA_4x8 || type==LUMA_4x4
    || type==CB_16AC || type==CB_8x8 || type==CB_8x4 || type==CB_4x8 || type==CB_4x4
    || type==CR_16AC || type==CR_8x8 || type==CR_8x4 || type==CR_4x8 || type==CR_4x4);
  int y_dc        = (type==LUMA_16DC || type==CB_16DC || type==CR_16DC); 
  int u_ac        = (type==CHROMA_AC && !currMB->is_v_block);
  int v_ac        = (type==CHROMA_AC &&  currMB->is_v_block);
  int chroma_dc   = (type==CHROMA_DC || type==CHROMA_DC_2x4 || type==CHROMA_DC_4x4);
  int u_dc        = (chroma_dc && !currMB->is_v_block);
  int v_dc        = (chroma_dc &&  currMB->is_v_block);
  int j           = (y_ac || u_ac || v_ac ? currMB->subblock_y : 0);
  int i           = (y_ac || u_ac || v_ac ? currMB->subblock_x : 0);
  int bit         = (y_dc ? 0 : y_ac ? 1 : u_dc ? 17 : v_dc ? 18 : u_ac ? 19 : 35);
  int default_bit = (currMB->is_intra_block ? 1 : 0);
  int upper_bit   = default_bit;
  int left_bit    = default_bit;
  int cbp_bit     = 1;  // always one for 8x8 mode
  int ctx;
  int bit_pos_a   = 0;
  int bit_pos_b   = 0;
  
  PixelPos block_a, block_b;
  if (y_ac)
  {
    get4x4Neighbour(currMB, i - 1, j    , p_Img->mb_size[IS_LUMA], &block_a);
    get4x4Neighbour(currMB, i    , j - 1, p_Img->mb_size[IS_LUMA], &block_b);
    if (block_a.available)
        bit_pos_a = 4*block_a.y + block_a.x;
      if (block_b.available)
        bit_pos_b = 4*block_b.y + block_b.x;
  }
  else if (y_dc)
  {
    get4x4Neighbour(currMB, i - 1, j    , p_Img->mb_size[IS_LUMA], &block_a);
    get4x4Neighbour(currMB, i    , j - 1, p_Img->mb_size[IS_LUMA], &block_b);
  }
  else if (u_ac||v_ac)
  {
    get4x4Neighbour(currMB, i - 1, j    , p_Img->mb_size[IS_CHROMA], &block_a);
    get4x4Neighbour(currMB, i    , j - 1, p_Img->mb_size[IS_CHROMA], &block_b);
    if (block_a.available)
      bit_pos_a = 4*block_a.y + block_a.x;
    if (block_b.available)
      bit_pos_b = 4*block_b.y + block_b.x;
  }
  else
  {
    get4x4Neighbour(currMB, i - 1, j    , p_Img->mb_size[IS_CHROMA], &block_a);
    get4x4Neighbour(currMB, i    , j - 1, p_Img->mb_size[IS_CHROMA], &block_b);
  }
  
  if (dec_picture->chroma_format_idc!=YUV444)
  {
    if (type!=LUMA_8x8)
    {
      //--- get bits from neighboring blocks ---
      if (block_b.available)
      {
        if(p_Img->mb_data[block_b.mb_addr].mb_type==IPCM)
          upper_bit=1;
        else
          upper_bit = get_bit(p_Img->mb_data[block_b.mb_addr].cbp_bits[0], bit + bit_pos_b);
      }
            
      if (block_a.available)
      {
        if(p_Img->mb_data[block_a.mb_addr].mb_type==IPCM)
          left_bit=1;
        else
          left_bit = get_bit(p_Img->mb_data[block_a.mb_addr].cbp_bits[0],bit + bit_pos_a);
      }
      
      
      ctx = 2 * upper_bit + left_bit;     
      //===== encode symbol =====
      cbp_bit = biari_decode_symbol (dep_dp, tex_ctx->bcbp_contexts[type2ctx_bcbp[type]] + ctx);
    }
  }
  else if( IS_INDEPENDENT(p_Img) )
  {
    if (type!=LUMA_8x8)
    {
      //--- get bits from neighbouring blocks ---
      if (block_b.available)
      {
        if(p_Img->mb_data[block_b.mb_addr].mb_type==IPCM)
          upper_bit = 1;
        else
          upper_bit = get_bit(p_Img->mb_data[block_b.mb_addr].cbp_bits[0],bit+bit_pos_b);
      }
      
      
      if (block_a.available)
      {
        if(p_Img->mb_data[block_a.mb_addr].mb_type==IPCM)
          left_bit = 1;
        else
          left_bit = get_bit(p_Img->mb_data[block_a.mb_addr].cbp_bits[0],bit+bit_pos_a);
      }
      
      
      ctx = 2 * upper_bit + left_bit;     
      //===== encode symbol =====
      cbp_bit = biari_decode_symbol (dep_dp, tex_ctx->bcbp_contexts[type2ctx_bcbp[type]] + ctx);
    }
  }
  else {
    if (block_b.available)
    {
      if(p_Img->mb_data[block_b.mb_addr].mb_type==IPCM)
        upper_bit=1;
      else
      {
        if(type==LUMA_8x8)
          upper_bit = get_bit(p_Img->mb_data[block_b.mb_addr].cbp_bits_8x8[0], bit + bit_pos_b);
        else if (type==CB_8x8)
          upper_bit = get_bit(p_Img->mb_data[block_b.mb_addr].cbp_bits_8x8[1], bit + bit_pos_b);
        else if (type==CR_8x8)
          upper_bit = get_bit(p_Img->mb_data[block_b.mb_addr].cbp_bits_8x8[2], bit + bit_pos_b);
        else if ((type==CB_4x4)||(type==CB_4x8)||(type==CB_8x4)||(type==CB_16AC)||(type==CB_16DC))
          upper_bit = get_bit(p_Img->mb_data[block_b.mb_addr].cbp_bits[1],bit+bit_pos_b);
        else if ((type==CR_4x4)||(type==CR_4x8)||(type==CR_8x4)||(type==CR_16AC)||(type==CR_16DC))
          upper_bit = get_bit(p_Img->mb_data[block_b.mb_addr].cbp_bits[2],bit+bit_pos_b);
        else
          upper_bit = get_bit(p_Img->mb_data[block_b.mb_addr].cbp_bits[0],bit+bit_pos_b);
      }
    }
    
    
    if (block_a.available)
    {
      if(p_Img->mb_data[block_a.mb_addr].mb_type==IPCM)
        left_bit=1;
      else
      {
        if(type==LUMA_8x8)
          left_bit = get_bit(p_Img->mb_data[block_a.mb_addr].cbp_bits_8x8[0],bit+bit_pos_a);
        else if (type==CB_8x8)
          left_bit = get_bit(p_Img->mb_data[block_a.mb_addr].cbp_bits_8x8[1],bit+bit_pos_a);
        else if (type==CR_8x8)
          left_bit = get_bit(p_Img->mb_data[block_a.mb_addr].cbp_bits_8x8[2],bit+bit_pos_a);
        else if ((type==CB_4x4)||(type==CB_4x8)||(type==CB_8x4)||(type==CB_16AC)||(type==CB_16DC))
          left_bit = get_bit(p_Img->mb_data[block_a.mb_addr].cbp_bits[1],bit+bit_pos_a);
        else if ((type==CR_4x4)||(type==CR_4x8)||(type==CR_8x4)||(type==CR_16AC)||(type==CR_16DC))
          left_bit = get_bit(p_Img->mb_data[block_a.mb_addr].cbp_bits[2],bit+bit_pos_a);
        else
          left_bit = get_bit(p_Img->mb_data[block_a.mb_addr].cbp_bits[0],bit+bit_pos_a);
      }
    }
    
    ctx = 2 * upper_bit + left_bit;
    //===== encode symbol =====
    cbp_bit = biari_decode_symbol (dep_dp, tex_ctx->bcbp_contexts[type2ctx_bcbp[type]] + ctx);
  }
 
  //--- set bits for current block ---
  bit = (y_dc ? 0 : y_ac ? 1 + j + (i >> 2) : u_dc ? 17 : v_dc ? 18 : u_ac ? 19 + j + (i >> 2) : 35 + j + (i >> 2)); 

  if (cbp_bit)
  {  
    if (type==LUMA_8x8) 
    {      
      currMB->cbp_bits[0] |= ((int64) 0x33 << bit   );
      
      if (dec_picture->chroma_format_idc==YUV444)
      {
        currMB->cbp_bits_8x8[0]   |= ((int64) 0x33 << bit   );
      }
    }
    else if (type==CB_8x8)
    {
      currMB->cbp_bits_8x8[1]   |= ((int64) 0x33 << bit   );      
      currMB->cbp_bits[1]   |= ((int64) 0x33 << bit   );
    }
    else if (type==CR_8x8)
    {
      currMB->cbp_bits_8x8[2]   |= ((int64) 0x33 << bit   );      
      currMB->cbp_bits[2]   |= ((int64) 0x33 << bit   );
    }
    else if (type==LUMA_8x4)
    {
      currMB->cbp_bits[0]   |= ((int64) 0x03 << bit   );
    }
    else if (type==CB_8x4)
    {
      currMB->cbp_bits[1]   |= ((int64) 0x03 << bit   );
    }
    else if (type==CR_8x4)
    {
      currMB->cbp_bits[2]   |= ((int64) 0x03 << bit   );
    }
    else if (type==LUMA_4x8)
    {
      currMB->cbp_bits[0]   |= ((int64) 0x11<< bit   );
    }
    else if (type==CB_4x8)
    {
      currMB->cbp_bits[1]   |= ((int64)0x11<< bit   );
    }
    else if (type==CR_4x8)
    {
      currMB->cbp_bits[2]   |= ((int64)0x11<< bit   );
    }
    else if ((type==CB_4x4)||(type==CB_16AC)||(type==CB_16DC))
    {
      currMB->cbp_bits[1]   |= ((int64)0x01<<bit);
    }
    else if ((type==CR_4x4)||(type==CR_16AC)||(type==CR_16DC))
    {
      currMB->cbp_bits[2]   |= ((int64)0x01<<bit);
    }
    else
    {
      currMB->cbp_bits[0]   |= ((int64)0x01<<bit);
    }
  }
  return cbp_bit;
}


int read_and_store_CBP_block_bit_normal (Macroblock              *currMB,
                                         DecodingEnvironmentPtr  dep_dp,
                                         int                     type)
{
  Slice *currSlice = currMB->p_Slice;
  ImageParameters *p_Img = currMB->p_Img;
  TextureInfoContexts *tex_ctx = currSlice->tex_ctx;

  int y_ac        = (type==LUMA_16AC || type==LUMA_8x8 || type==LUMA_8x4 || type==LUMA_4x8 || type==LUMA_4x4);
  int y_dc        = (type==LUMA_16DC); 
  int u_ac        = (type==CHROMA_AC && !currMB->is_v_block);
  int v_ac        = (type==CHROMA_AC &&  currMB->is_v_block);
  int chroma_dc   = (type==CHROMA_DC || type==CHROMA_DC_2x4 || type==CHROMA_DC_4x4);
  int u_dc        = (chroma_dc && !currMB->is_v_block);
  int v_dc        = (chroma_dc &&  currMB->is_v_block);
  int j           = (y_ac || u_ac || v_ac ? currMB->subblock_y : 0);
  int i           = (y_ac || u_ac || v_ac ? currMB->subblock_x : 0);
  int bit         = (y_dc ? 0 : y_ac ? 1 : u_dc ? 17 : v_dc ? 18 : u_ac ? 19 : 35);
  int default_bit = (currMB->is_intra_block ? 1 : 0);
  int upper_bit   = default_bit;
  int left_bit    = default_bit;
  int cbp_bit     = 1;  // always one for 8x8 mode
  int ctx;
  int bit_pos_a   = 0;
  int bit_pos_b   = 0;

  PixelPos block_a, block_b;

  if (y_ac)
  {
    get4x4Neighbour(currMB, i - 1, j    , p_Img->mb_size[IS_LUMA], &block_a);
    get4x4Neighbour(currMB, i    , j - 1, p_Img->mb_size[IS_LUMA], &block_b);
    if (block_a.available)
      bit_pos_a = 4*block_a.y + block_a.x;
    if (block_b.available)
      bit_pos_b = 4*block_b.y + block_b.x;
  }
  else if (y_dc)
  {
    get4x4Neighbour(currMB, i - 1, j    , p_Img->mb_size[IS_LUMA], &block_a);
    get4x4Neighbour(currMB, i    , j - 1, p_Img->mb_size[IS_LUMA], &block_b);
  }
  else if (u_ac||v_ac)
  {
    get4x4Neighbour(currMB, i - 1, j    , p_Img->mb_size[IS_CHROMA], &block_a);
    get4x4Neighbour(currMB, i    , j - 1, p_Img->mb_size[IS_CHROMA], &block_b);
    if (block_a.available)
      bit_pos_a = 4*block_a.y + block_a.x;
    if (block_b.available)
      bit_pos_b = 4*block_b.y + block_b.x;
  }
  else
  {
    get4x4Neighbour(currMB, i - 1, j    , p_Img->mb_size[IS_CHROMA], &block_a);
    get4x4Neighbour(currMB, i    , j - 1, p_Img->mb_size[IS_CHROMA], &block_b);
  }

  if (type!=LUMA_8x8)
  {
    //--- get bits from neighboring blocks ---
    if (block_b.available)
    {
      if(p_Img->mb_data[block_b.mb_addr].mb_type==IPCM)
        upper_bit=1;
      else
        upper_bit = get_bit(p_Img->mb_data[block_b.mb_addr].cbp_bits[0], bit + bit_pos_b);
    }

    if (block_a.available)
    {
      if(p_Img->mb_data[block_a.mb_addr].mb_type==IPCM)
        left_bit=1;
      else
        left_bit = get_bit(p_Img->mb_data[block_a.mb_addr].cbp_bits[0],bit + bit_pos_a);
    }

    ctx = 2 * upper_bit + left_bit;     
    //===== encode symbol =====
    cbp_bit = biari_decode_symbol (dep_dp, tex_ctx->bcbp_contexts[type2ctx_bcbp[type]] + ctx);
  }

  //--- set bits for current block ---
  bit = (y_dc ? 0 : y_ac ? 1 + j + (i >> 2) : u_dc ? 17 : v_dc ? 18 : u_ac ? 19 + j + (i >> 2) : 35 + j + (i >> 2)); 

  if (cbp_bit)
  {  
    if (type==LUMA_8x8) 
    {      
      currMB->cbp_bits[0] |= ((int64) 0x33 << bit   );      
    }
    else if (type==LUMA_8x4)
    {
      currMB->cbp_bits[0]   |= ((int64) 0x03 << bit   );
    }
    else if (type==LUMA_4x8)
    {
      currMB->cbp_bits[0]   |= ((int64) 0x11<< bit   );
    }
    else
    {
      currMB->cbp_bits[0]   |= ((int64)0x01<<bit);
    }
  }
  return cbp_bit;
}






//===== position -> ctx for MAP =====
//--- zig-zag scan ----
static const byte  pos2ctx_map8x8 [] = { 0,  1,  2,  3,  4,  5,  5,  4,  4,  3,  3,  4,  4,  4,  5,  5,
                                         4,  4,  4,  4,  3,  3,  6,  7,  7,  7,  8,  9, 10,  9,  8,  7,
                                         7,  6, 11, 12, 13, 11,  6,  7,  8,  9, 14, 10,  9,  8,  6, 11,
                                        12, 13, 11,  6,  9, 14, 10,  9, 11, 12, 13, 11 ,14, 10, 12, 14}; // 15 CTX
static const byte  pos2ctx_map8x4 [] = { 0,  1,  2,  3,  4,  5,  7,  8,  9, 10, 11,  9,  8,  6,  7,  8,
                                         9, 10, 11,  9,  8,  6, 12,  8,  9, 10, 11,  9, 13, 13, 14, 14}; // 15 CTX
static const byte  pos2ctx_map4x4 [] = { 0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11, 12, 13, 14, 14}; // 15 CTX
static const byte  pos2ctx_map2x4c[] = { 0,  0,  1,  1,  2,  2,  2,  2,  2,  2,  2,  2,  2,  2,  2,  2}; // 15 CTX
static const byte  pos2ctx_map4x4c[] = { 0,  0,  0,  0,  1,  1,  1,  1,  2,  2,  2,  2,  2,  2,  2,  2}; // 15 CTX
static const byte* pos2ctx_map    [] = {pos2ctx_map4x4, pos2ctx_map4x4, pos2ctx_map8x8, pos2ctx_map8x4,
                                        pos2ctx_map8x4, pos2ctx_map4x4, pos2ctx_map4x4, pos2ctx_map4x4,
                                        pos2ctx_map2x4c, pos2ctx_map4x4c, 
                                        pos2ctx_map4x4, pos2ctx_map4x4, pos2ctx_map8x8,pos2ctx_map8x4,
                                        pos2ctx_map8x4, pos2ctx_map4x4,
                                        pos2ctx_map4x4, pos2ctx_map4x4, pos2ctx_map8x8,pos2ctx_map8x4,
                                        pos2ctx_map8x4,pos2ctx_map4x4};
//--- interlace scan ----
//taken from ABT
static const byte  pos2ctx_map8x8i[] = { 0,  1,  1,  2,  2,  3,  3,  4,  5,  6,  7,  7,  7,  8,  4,  5,
                                         6,  9, 10, 10,  8, 11, 12, 11,  9,  9, 10, 10,  8, 11, 12, 11,
                                         9,  9, 10, 10,  8, 11, 12, 11,  9,  9, 10, 10,  8, 13, 13,  9,
                                         9, 10, 10,  8, 13, 13,  9,  9, 10, 10, 14, 14, 14, 14, 14, 14}; // 15 CTX
static const byte  pos2ctx_map8x4i[] = { 0,  1,  2,  3,  4,  5,  6,  3,  4,  5,  6,  3,  4,  7,  6,  8,
                                         9,  7,  6,  8,  9, 10, 11, 12, 12, 10, 11, 13, 13, 14, 14, 14}; // 15 CTX
static const byte  pos2ctx_map4x8i[] = { 0,  1,  1,  1,  2,  3,  3,  4,  4,  4,  5,  6,  2,  7,  7,  8,
                                         8,  8,  5,  6,  9, 10, 10, 11, 11, 11, 12, 13, 13, 14, 14, 14}; // 15 CTX
static const byte* pos2ctx_map_int[] = {pos2ctx_map4x4, pos2ctx_map4x4, pos2ctx_map8x8i,pos2ctx_map8x4i,
                                        pos2ctx_map4x8i,pos2ctx_map4x4, pos2ctx_map4x4, pos2ctx_map4x4,
                                        pos2ctx_map2x4c, pos2ctx_map4x4c,
                                        pos2ctx_map4x4, pos2ctx_map4x4, pos2ctx_map8x8i,pos2ctx_map8x4i,
                                        pos2ctx_map8x4i,pos2ctx_map4x4,
                                        pos2ctx_map4x4, pos2ctx_map4x4, pos2ctx_map8x8i,pos2ctx_map8x4i,
                                        pos2ctx_map8x4i,pos2ctx_map4x4};

//===== position -> ctx for LAST =====
static const byte  pos2ctx_last8x8 [] = { 0,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,
                                          2,  2,  2,  2,  2,  2,  2,  2,  2,  2,  2,  2,  2,  2,  2,  2,
                                          3,  3,  3,  3,  3,  3,  3,  3,  4,  4,  4,  4,  4,  4,  4,  4,
                                          5,  5,  5,  5,  6,  6,  6,  6,  7,  7,  7,  7,  8,  8,  8,  8}; //  9 CTX
static const byte  pos2ctx_last8x4 [] = { 0,  1,  1,  1,  1,  1,  1,  1,  2,  2,  2,  2,  2,  2,  2,  2,
                                          3,  3,  3,  3,  4,  4,  4,  4,  5,  5,  6,  6,  7,  7,  8,  8}; //  9 CTX

static const byte  pos2ctx_last4x4 [] = { 0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11, 12, 13, 14, 15}; // 15 CTX
static const byte  pos2ctx_last2x4c[] = { 0,  0,  1,  1,  2,  2,  2,  2,  2,  2,  2,  2,  2,  2,  2,  2}; // 15 CTX
static const byte  pos2ctx_last4x4c[] = { 0,  0,  0,  0,  1,  1,  1,  1,  2,  2,  2,  2,  2,  2,  2,  2}; // 15 CTX
static const byte* pos2ctx_last    [] = {pos2ctx_last4x4, pos2ctx_last4x4, pos2ctx_last8x8, pos2ctx_last8x4,
                                         pos2ctx_last8x4, pos2ctx_last4x4, pos2ctx_last4x4, pos2ctx_last4x4,
                                         pos2ctx_last2x4c, pos2ctx_last4x4c,
                                         pos2ctx_last4x4, pos2ctx_last4x4, pos2ctx_last8x8,pos2ctx_last8x4,
                                         pos2ctx_last8x4, pos2ctx_last4x4,
                                         pos2ctx_last4x4, pos2ctx_last4x4, pos2ctx_last8x8,pos2ctx_last8x4,
                                         pos2ctx_last8x4, pos2ctx_last4x4};



int read_significance_map (Macroblock              *currMB,
                           DecodingEnvironmentPtr  dep_dp,
                           int                     type,
                           int                     coeff[])
{
  int   i, sig;
  int   coeff_ctr = 0;
  int   i0        = 0;
  int   i1        = maxpos[type];
  ImageParameters *p_Img = currMB->p_Img;

  int               fld       = ( p_Img->structure!=FRAME || currMB->mb_field );
  const byte **pos2ctx_Map = (fld) ? pos2ctx_map_int : pos2ctx_map;
  Slice *currSlice = currMB->p_Slice;
  TextureInfoContexts *tex_ctx = currSlice->tex_ctx;

  BiContextTypePtr  map_ctx   = tex_ctx->map_contexts[fld][type2ctx_map [type]];
  BiContextTypePtr  last_ctx  = tex_ctx->last_contexts[fld][type2ctx_last[type]];

  if (!c1isdc[type])
  {
    ++i0; 
    ++i1; 
    coeff--;
  }

  for (i=i0; i < i1; ++i) // if last coeff is reached, it has to be significant
  {
    //--- read significance symbol ---
    sig = biari_decode_symbol   (dep_dp, map_ctx + pos2ctx_Map [type][i]);

    if (sig)
    {
      coeff[i] = 1;
      ++coeff_ctr;
      //--- read last coefficient symbol ---
      if (biari_decode_symbol (dep_dp, last_ctx + pos2ctx_last[type][i]))
      {
        memset(&coeff[i + 1], 0, (i1 - i) * sizeof(int));
        i = i1;
      }
    }
    else
    {
      coeff[i] = 0;
    }
  }
  //--- last coefficient must be significant if no last symbol was received ---
  if (i < i1 + 1)
  {
    coeff[i] = 1;
    ++coeff_ctr;
  }

  return coeff_ctr;
}



void read_significant_coefficients (DecodingEnvironmentPtr  dep_dp,
                                    TextureInfoContexts    *tex_ctx,
                                    int                     type,
                                    int                     coeff[])
{
  int   i, ctx;
  int   c1 = 1;
  int   c2 = 0;
  BiContextType *one_contexts = tex_ctx->one_contexts[type2ctx_one[type]];
  BiContextType *abs_contexts = tex_ctx->abs_contexts[type2ctx_abs[type]];

  for (i=maxpos[type]; i>=0; i--)
  {
    if (coeff[i]!=0)
    {
      ctx = imin (c1,4);
      coeff[i] += biari_decode_symbol (dep_dp, one_contexts + ctx);
      if (coeff[i]==2)
      {
        ctx = imin (c2++, max_c2[type]);
        coeff[i] += unary_exp_golomb_level_decode (dep_dp, abs_contexts + ctx);
        c1=0;
      }
      else if (c1)
      {
        ++c1;
      }
      if (biari_decode_symbol_eq_prob(dep_dp))
      {
        coeff[i] *= -1;
      }
    }
  }
}


void readRunLevel_CABAC (Macroblock *currMB, 
                         SyntaxElement  *se,
                         DecodingEnvironmentPtr dep_dp)
{
  Slice *currSlice = currMB->p_Slice;
  ImageParameters *p_Img = currMB->p_Img;
  seq_parameter_set_rbsp_t *active_sps = p_Img->active_sps;

  // This can be moved into a sequence level initialization function
  if (active_sps->chroma_format_idc == YUV444)
    currMB->read_and_store_CBP_block_bit = read_and_store_CBP_block_bit_444;
  else
    currMB->read_and_store_CBP_block_bit = read_and_store_CBP_block_bit_normal; 


  //--- read coefficients for whole block ---
  if (currSlice->coeff_ctr < 0)
  {
    //===== decode CBP-BIT =====
    if ((currSlice->coeff_ctr = currMB->read_and_store_CBP_block_bit (currMB, dep_dp, se->context) )!=0)
    {
      //===== decode significance map =====
      currSlice->coeff_ctr = read_significance_map (currMB, dep_dp, se->context, currSlice->coeff);

      //===== decode significant coefficients =====
      read_significant_coefficients     (dep_dp, currSlice->tex_ctx, se->context, currSlice->coeff);
    }
  }

  //--- set run and level ---
  if (currSlice->coeff_ctr)
  {
    //--- set run and level (coefficient) ---
    for (se->value2=0; currSlice->coeff[currSlice->pos]==0; ++currSlice->pos, ++se->value2);
    se->value1 = currSlice->coeff[currSlice->pos++];
  }
  else
  {
    //--- set run and level (EOB) ---
    se->value1 = se->value2 = 0;
  }
  //--- decrement coefficient counter and re-set position ---
  if (currSlice->coeff_ctr-- == 0) currSlice->pos=0;

#if TRACE
  fprintf(p_Dec->p_trace, "@%-6d %-53s %3d  %3d\n",symbolCount++, se->tracestring, se->value1,se->value2);
  fflush(p_Dec->p_trace);
#endif
}

int readSyntaxElement_CABAC(SyntaxElement *se, ImageParameters *p_Img, DataPartition *this_dataPart)
{
  Macroblock *currMB = &p_Img->mb_data[p_Img->current_mb_nr];
  DecodingEnvironmentPtr dep_dp = &(this_dataPart->de_cabac);
  int curr_len = arideco_bits_read(dep_dp);

  // perform the actual decoding by calling the appropriate method
  se->reading(currMB, se, dep_dp);
  //read again and minus curr_len = arideco_bits_read(dep_dp); from above
  se->len = (arideco_bits_read(dep_dp) - curr_len);

#if (TRACE==2)
  fprintf(p_Dec->p_trace, "curr_len: %d\n",curr_len);
  fprintf(p_Dec->p_trace, "se_len: %d\n",se->len);
#endif

  return (se->len); 
}


static unsigned int unary_bin_max_decode(DecodingEnvironmentPtr dep_dp,
                                  BiContextTypePtr ctx,
                                  int ctx_offset,
                                  unsigned int max_symbol)
{
  unsigned int symbol =  biari_decode_symbol(dep_dp, ctx );

  if (symbol==0 || (max_symbol == 0))
    return symbol;
  else
  {    
    unsigned int l;
    ctx += ctx_offset;
    symbol = 0;
    do
    {
      l = biari_decode_symbol(dep_dp, ctx);
      ++symbol;
    }
    while( (l != 0) && (symbol < max_symbol) );

    if ((l != 0) && (symbol == max_symbol))
      ++symbol;
    return symbol;
  }
}


static unsigned int unary_bin_decode(DecodingEnvironmentPtr dep_dp,
                              BiContextTypePtr ctx,
                              int ctx_offset)
{
  unsigned int symbol = biari_decode_symbol(dep_dp, ctx );

  if (symbol == 0)
    return 0;
  else
  {
    unsigned int l;
    ctx += ctx_offset;;
    symbol = 0;
    do
    {
      l=biari_decode_symbol(dep_dp, ctx);
      ++symbol;
    }
    while( l != 0 );
    return symbol;
  }
}


int cabac_startcode_follows(Slice *currSlice, int eos_bit)
{
  unsigned int  bit;

  if( eos_bit )
  {
    const byte   *partMap    = assignSE2partition[currSlice->dp_mode];
    DataPartition *dP = &(currSlice->partArr[partMap[SE_MBTYPE]]);  
    DecodingEnvironmentPtr dep_dp = &(dP->de_cabac);

    bit = biari_decode_final (dep_dp); //GB

#if TRACE
    fprintf(p_Dec->p_trace, "@%-6d %-63s (%3d)\n",symbolCount++, "end_of_slice_flag", bit);
    fflush(p_Dec->p_trace);
#endif
  }
  else
  {
    bit = 0;
  }

  return (bit == 1 ? 1 : 0);
}

unsigned int exp_golomb_decode_eq_prob( DecodingEnvironmentPtr dep_dp,
                                        int k)
{
  unsigned int l;
  int symbol = 0;
  int binary_symbol = 0;

  do
  {
    l = biari_decode_symbol_eq_prob(dep_dp);
    if (l == 1)
    {
      symbol += (1<<k);
      ++k;
    }
  }
  while (l!=0);

  while (k--)                             //next binary part
    if (biari_decode_symbol_eq_prob(dep_dp)==1)
      binary_symbol |= (1<<k);

  return (unsigned int) (symbol + binary_symbol);
}


static unsigned int unary_exp_golomb_level_decode( DecodingEnvironmentPtr dep_dp,
                                                  BiContextTypePtr ctx)
{
  unsigned int symbol = biari_decode_symbol(dep_dp, ctx );

  if (symbol==0)
    return 0;
  else
  {
    unsigned int l, k = 1;
    unsigned int exp_start = 13;

    symbol=0;

    do
    {
      l=biari_decode_symbol(dep_dp, ctx);
      ++symbol;
      ++k;
    }
    while((l != 0) && (k != exp_start));
    if (l!=0)
      symbol += exp_golomb_decode_eq_prob(dep_dp,0)+1;
    return symbol;
  }
}




static unsigned int unary_exp_golomb_mv_decode(DecodingEnvironmentPtr dep_dp,
                                               BiContextTypePtr ctx,
                                               unsigned int max_bin)
{
  unsigned int symbol = biari_decode_symbol(dep_dp, ctx );

  if (symbol == 0)
    return 0;
  else
  {
    unsigned int exp_start = 8;
    unsigned int l,k = 1;
    unsigned int bin = 1;

    symbol=0;

    ++ctx;
    do
    {
      l=biari_decode_symbol(dep_dp, ctx);
      if ((++bin)==2) ctx++;
      if (bin==max_bin) 
        ++ctx;
      ++symbol;
      ++k;
    }
    while((l!=0) && (k!=exp_start));
    if (l!=0)
      symbol += exp_golomb_decode_eq_prob(dep_dp,3) + 1;
    return symbol;
  }
}


void readIPCM_CABAC(Slice *currSlice, struct datapartition *dP)
{
  ImageParameters *p_Img = currSlice->p_Img;
  StorablePicture *dec_picture = p_Img->dec_picture;
  Bitstream* currStream = dP->bitstream;
  DecodingEnvironmentPtr dep = &(dP->de_cabac);
  byte *buf = currStream->streamBuffer;
  int BitstreamLengthInBits = (dP->bitstream->bitstream_length << 3) + 7;

  int val = 0;

  int bits_read = 0;
  int bitoffset, bitdepth;
  int uv, i, j;

  while (dep->DbitsLeft >= 8)
  {
    dep->Dvalue   >>= 8;
    dep->DbitsLeft -= 8;
    (*dep->Dcodestrm_len)--;
  }
  
  bitoffset = (*dep->Dcodestrm_len) << 3;

  // read luma values
  bitdepth = p_Img->bitdepth_luma;
  for(i=0;i<MB_BLOCK_SIZE;++i)
  {
    for(j=0;j<MB_BLOCK_SIZE;++j)
    {
      bits_read += GetBits(buf, bitoffset, &val, BitstreamLengthInBits, bitdepth);
#if TRACE
      tracebits2("pcm_byte luma", bitdepth, val);
#endif
      currSlice->cof[0][i][j] = val;

      bitoffset += bitdepth;
    }
  }

  // read chroma values
  bitdepth = p_Img->bitdepth_chroma;
  if ((dec_picture->chroma_format_idc != YUV400) && !IS_INDEPENDENT(p_Img))
  {
    for (uv=1; uv<3; ++uv)
    {
      for(i=0;i<p_Img->mb_cr_size_y;++i)
      {
        for(j=0;j<p_Img->mb_cr_size_x;++j)
        {
          bits_read += GetBits(buf, bitoffset, &val, BitstreamLengthInBits, bitdepth);
#if TRACE
          tracebits2("pcm_byte chroma", bitdepth, val);
#endif
          currSlice->cof[uv][i][j] = val;

          bitoffset += bitdepth;
        }
      }
    }
  }

  (*dep->Dcodestrm_len) += ( bits_read >> 3);
  if (bits_read & 7)
  {
    ++(*dep->Dcodestrm_len);
  }
}

---

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