cabac.c

G729、h263、h264、MPEG4四种最流行的音频和视频标准的压缩和解压算法的源代码.rar

      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;
        if (csym) biari_encode_symbol (eep_dp, 1, &ctx->mb_type_contexts[2][6]);
        else      biari_encode_symbol (eep_dp, 0, &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);
        if (csym) biari_encode_symbol (eep_dp, 1, &ctx->mb_type_contexts[2][6]);
        else      biari_encode_symbol (eep_dp, 0, &ctx->mb_type_contexts[2][6]);
        csym=(((act_sym-3)>>1)&0x01);
        if (csym) biari_encode_symbol (eep_dp, 1, &ctx->mb_type_contexts[2][6]);
        else      biari_encode_symbol (eep_dp, 0, &ctx->mb_type_contexts[2][6]);
        csym=((act_sym-3)&0x01);
        if (csym) biari_encode_symbol (eep_dp, 1, &ctx->mb_type_contexts[2][6]);
        else      biari_encode_symbol (eep_dp, 0, &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]);
        if (act_sym==11)  biari_encode_symbol (eep_dp, 0, &ctx->mb_type_contexts[2][6]);
        else              biari_encode_symbol (eep_dp, 1, &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);
        if (csym) biari_encode_symbol (eep_dp, 1, &ctx->mb_type_contexts[2][6]);
        else      biari_encode_symbol (eep_dp, 0, &ctx->mb_type_contexts[2][6]);
        csym=(((act_sym-12)>>2)&0x01);
        if (csym) biari_encode_symbol (eep_dp, 1, &ctx->mb_type_contexts[2][6]);
        else      biari_encode_symbol (eep_dp, 0, &ctx->mb_type_contexts[2][6]);
        csym=(((act_sym-12)>>1)&0x01);
        if (csym) biari_encode_symbol (eep_dp, 1, &ctx->mb_type_contexts[2][6]);
        else      biari_encode_symbol (eep_dp, 0, &ctx->mb_type_contexts[2][6]);
        csym=((act_sym-12)&0x01);
        if (csym) biari_encode_symbol (eep_dp, 1, &ctx->mb_type_contexts[2][6]); 
        else      biari_encode_symbol (eep_dp, 0, &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, (unsigned char) 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 );
        if (act_sym==1)
        {
          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 );
        }
      }

      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, (unsigned char) act_sym, ctx->mb_type_contexts[1] + act_ctx );
      act_sym  = mode_sym%2;
      biari_encode_symbol(eep_dp, (unsigned char) 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, 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]);
      if (act_sym==0)   biari_encode_symbol (eep_dp, 0, &ctx->b8_type_contexts[1][3]);
      else              biari_encode_symbol (eep_dp, 1, &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);
      if (csym) biari_encode_symbol (eep_dp, 1, &ctx->b8_type_contexts[1][3]);
      else      biari_encode_symbol (eep_dp, 0, &ctx->b8_type_contexts[1][3]);
      csym=((act_sym-2)&0x01);
      if (csym) biari_encode_symbol (eep_dp, 1, &ctx->b8_type_contexts[1][3]);
      else      biari_encode_symbol (eep_dp, 0, &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)
      {
        biari_encode_symbol (eep_dp, 1, &ctx->b8_type_contexts[1][3]);
        csym=((act_sym-6)&0x01);
        if (csym) biari_encode_symbol (eep_dp, 1, &ctx->b8_type_contexts[1][3]);
        else      biari_encode_symbol (eep_dp, 0, &ctx->b8_type_contexts[1][3]);
      }
      else
      {
        biari_encode_symbol (eep_dp, 0, &ctx->b8_type_contexts[1][3]);
        csym=(((act_sym-6)>>1)&0x01);
        if (csym) biari_encode_symbol (eep_dp, 1, &ctx->b8_type_contexts[1][3]);
        else      biari_encode_symbol (eep_dp, 0, &ctx->b8_type_contexts[1][3]);
        csym=((act_sym-6)&0x01);
        if (csym) biari_encode_symbol (eep_dp, 1, &ctx->b8_type_contexts[1][3]);
        else      biari_encode_symbol (eep_dp, 0, &ctx->b8_type_contexts[1][3]);
      }
    }
  }
}


/*!
 ****************************************************************************
 * \brief
 *    This function is used to arithmetically encode a pair of
 *    intra prediction modes of a given MB.
 ****************************************************************************
 */
void writeIntraPredMode_CABAC(SyntaxElement *se, EncodingEnvironmentPtr eep_dp)
{
  TextureInfoContexts *ctx = img->currentSlice->tex_ctx;
  
  // use_most_probable_mode
  if (se->value1 == -1)
    biari_encode_symbol(eep_dp, 1, ctx->ipr_contexts);
  else
  {
    biari_encode_symbol(eep_dp, 0, ctx->ipr_contexts);
        
    // remaining_mode_selector
    biari_encode_symbol(eep_dp,(signed short)( se->value1 & 0x1    ), ctx->ipr_contexts+1);
    biari_encode_symbol(eep_dp,(signed short)((se->value1 & 0x2)>>1), ctx->ipr_contexts+1);
    biari_encode_symbol(eep_dp,(signed short)((se->value1 & 0x4)>>2), ctx->ipr_contexts+1);
  }
}
/*!
 ****************************************************************************
 * \brief
 *    This function is used to arithmetically encode the reference
 *    parameter of a given MB.
 ****************************************************************************
 */
void writeRefFrame_CABAC(SyntaxElement *se, EncodingEnvironmentPtr eep_dp)
{
  MotionInfoContexts  *ctx    = img->currentSlice->mot_ctx;
  Macroblock          *currMB = &img->mb_data[img->current_mb_nr];
  int                 addctx  = 0;

  int   a, b;
  int   act_ctx;
  int   act_sym;
  int** refframe_array = enc_picture->ref_idx[se->value2];

  int bslice = (img->type==B_SLICE);

  int   b8a, b8b;

  PixelPos block_a, block_b;
  
  getLuma4x4Neighbour(img->current_mb_nr, img->subblock_x, img->subblock_y, -1,  0, &block_a);
  getLuma4x4Neighbour(img->current_mb_nr, img->subblock_x, img->subblock_y,  0, -1, &block_b);

  b8a=((block_a.x/2)%2)+2*((block_a.y/2)%2);
  b8b=((block_b.x/2)%2)+2*((block_b.y/2)%2);

  
  if (!block_b.available)
    b=0;
  else if (IS_DIRECT(&img->mb_data[block_b.mb_addr]) || (img->mb_data[block_b.mb_addr].b8mode[b8b]==0 && bslice))
    b=0;
  else
  {
    if (img->MbaffFrameFlag && (currMB->mb_field == 0) && (img->mb_data[block_b.mb_addr].mb_field == 1))
      b = (refframe_array[block_b.pos_x][block_b.pos_y] > 1 ? 1 : 0);
    else
      b = (refframe_array[block_b.pos_x][block_b.pos_y] > 0 ? 1 : 0);
  }

  if (!block_a.available)
    a=0;
  else if (IS_DIRECT(&img->mb_data[block_a.mb_addr]) || (img->mb_data[block_a.mb_addr].b8mode[b8a]==0 && bslice))
    a=0;
  else 
  {
    if (img->MbaffFrameFlag && (currMB->mb_field == 0) && (img->mb_data[block_a.mb_addr].mb_field == 1))
      a = (refframe_array[block_a.pos_x][block_a.pos_y] > 1 ? 1 : 0);
    else
      a = (refframe_array[block_a.pos_x][block_a.pos_y] > 0 ? 1 : 0);
  }

  act_ctx     = a + 2*b; 
  se->context = act_ctx; // store context
  act_sym     = se->value1;

  if (act_sym==0)
  {
    biari_encode_symbol(eep_dp, 0, ctx->ref_no_contexts[addctx] + act_ctx );
  }
  else
  {
    biari_encode_symbol(eep_dp, 1, ctx->ref_no_contexts[addctx] + act_ctx);
    act_sym--;
    act_ctx=4;
    unary_bin_encode(eep_dp, act_sym,ctx->ref_no_contexts[addctx]+act_ctx,1);
  }
}

/*!
 ****************************************************************************
 * \brief
 *    This function is used to arithmetically encode the coded
 *    block pattern of a given delta quant.
 ****************************************************************************
 */
void writeDquant_CABAC(SyntaxElement *se, EncodingEnvironmentPtr eep_dp)
{
  MotionInfoContexts *ctx = img->currentSlice->mot_ctx;

  int act_ctx;
  int act_sym;
  int dquant = se->value1;
  int sign=0;

  Macroblock     *currMB       = &img->mb_data[img->current_mb_nr];

  last_dquant=currMB->prev_delta_qp;