cabac.c

H.264编码解码器源码(c语言).zip

      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   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 && img->mb_data[block_b.mb_addr].b8pdir[b8b]==2))
    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 && img->mb_data[block_a.mb_addr].b8pdir[b8a]==2))
    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;
  Macroblock *currMB = &img->mb_data[img->current_mb_nr];

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

  if (dquant <= 0)
    sign = 1;
  act_sym = abs(dquant) << 1;

  act_sym += sign;
  act_sym --;

  if (currMB->mb_available_left == NULL)
    act_ctx = 0;
  else
    act_ctx = ( ((currMB->mb_available_left)->delta_qp != 0) ? 1 : 0);

  if (act_sym==0)
  {
    biari_encode_symbol(eep_dp, 0, ctx->delta_qp_contexts + act_ctx );
  }
  else
  {
    biari_encode_symbol(eep_dp, 1, ctx->delta_qp_contexts + act_ctx);
    act_ctx=2;
    act_sym--;
    unary_bin_encode(eep_dp, act_sym,ctx->delta_qp_contexts+act_ctx,1);
  }
}

/*!
 ****************************************************************************
 * \brief
 *    This function is used to arithmetically encode the motion
 *    vector data of a B-frame MB.
 ****************************************************************************
 */
void writeMVD_CABAC(SyntaxElement *se, EncodingEnvironmentPtr eep_dp)
{
  int i = img->subblock_x;
  int j = img->subblock_y;
  int a, b;
  int act_ctx;
  int act_sym;
  int mv_pred_res;
  int mv_local_err;
  int mv_sign;
  int list_idx = se->value2 & 0x01;
  int k = (se->value2>>1); // MVD component

  PixelPos block_a, block_b;

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

  getLuma4x4Neighbour(img->current_mb_nr, i, j, -1,  0, &block_a);
  getLuma4x4Neighbour(img->current_mb_nr, i, j,  0, -1, &block_b);

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

  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;
  }
  mv_pred_res = se->value1;
  se->context = act_ctx;

  act_sym = absm(mv_pred_res);

  if (act_sym == 0)
    biari_encode_symbol(eep_dp, 0, &ctx->mv_res_contexts[0][act_ctx] );
  else
  {
    biari_encode_symbol(eep_dp, 1, &ctx->mv_res_contexts[0][act_ctx] );
    act_sym--;
    act_ctx=5*k;
    unary_exp_golomb_mv_encode(eep_dp,act_sym,ctx->mv_res_contexts[1]+act_ctx,3);
    mv_sign = (mv_pred_res<0) ? 1: 0;
    biari_encode_symbol_eq_prob(eep_dp, (unsigned char) mv_sign);
  }
}


/*!
 ****************************************************************************
 * \brief
 *    This function is used to arithmetically encode the chroma
 *    intra prediction mode of an 8x8 block
 ****************************************************************************
 */
void writeCIPredMode_CABAC(SyntaxElement *se, EncodingEnvironmentPtr eep_dp)
{
  TextureInfoContexts *ctx     = img->currentSlice->tex_ctx;
  Macroblock          *currMB  = &img->mb_data[img->current_mb_nr];
  int                 act_ctx,a,b;
  int                 act_sym  = se->value1;

  if (currMB->mb_available_up == NULL) b = 0;
  else  b = ( ((currMB->mb_available_up)->c_ipred_mode != 0) ? 1 : 0);

  if (currMB->mb_available_left == NULL) a = 0;
  else  a = ( ((currMB->mb_available_left)->c_ipred_mode != 0) ? 1 : 0);

  act_ctx = a+b;

  if (act_sym==0) biari_encode_symbol(eep_dp, 0, ctx->cipr_contexts + act_ctx );
  else
  {
    biari_encode_symbol(eep_dp, 1, ctx->cipr_contexts + act_ctx );
    unary_bin_max_encode(eep_dp,(unsigned int) (act_sym-1),ctx->cipr_contexts+3,0,2);
  }
}


/*!
 ****************************************************************************
 * \brief
 *    This function is used to arithmetically encode the coded
 *    block pattern of an 8x8 block
 ****************************************************************************
 */
void writeCBP_BIT_CABAC (int b8, int bit, int cbp, Macroblock* currMB, int inter, EncodingEnvironmentPtr eep_dp)
{
  int a, b;

  //===== GET CONTEXT FOR CBP-BIT =====
  if (b8/2 == 0) // upper block is in upper macroblock
  {
    if (currMB->mb_available_up == NULL)
      b = 0;
    else
      b = ((currMB->mb_available_up->cbp & (1<<(b8+2))) == 0 ? 1 : 0);
  }
  else
    b   = ((cbp & (1<<(b8-2))) == 0 ? 1: 0);
  if (b8%2 == 0) // left block is in left macroblock
  {
    if (currMB->mb_available_left == NULL)
      a = 0;
    else
      a = ((currMB->mb_available_left->cbp & (1<<(b8+1))) == 0 ? 1 : 0);
  }
  else
    a   = ((cbp & (1<<(b8-1))) == 0 ? 1: 0);

  //===== WRITE BIT =====
  biari_encode_symbol (eep_dp, (unsigned char) bit,
                       img->currentSlice->tex_ctx->cbp_contexts[0] + a+2*b);

}

/*!
 ****************************************************************************
 * \brief
 *    This function is used to arithmetically encode the coded
 *    block pattern of a macroblock
 ****************************************************************************
 */
void writeCBP_CABAC(SyntaxElement *se, EncodingEnvironmentPtr eep_dp)
{
  TextureInfoContexts *ctx = img->currentSlice->tex_ctx;
  Macroblock *currMB = &img->mb_data[img->current_mb_nr];

  int a, b;
  int curr_cbp_ctx, curr_cbp_idx;
  int cbp = se->value1; // symbol to encode
  int cbp_bit;
  int b8;

  for (b8=0; b8<4; b8++)
  {
    curr_cbp_idx = (currMB->b8mode[b8] == IBLOCK ? 0 : 1);
    writeCBP_BIT_CABAC (b8, cbp&(1<<b8), cbp, currMB, curr_cbp_idx, eep_dp);
  }

  if ( se->type == SE_CBP_INTRA )
    curr_cbp_idx = 0;
  else
    curr_cbp_idx = 1;

  // coding of chroma part
  b = 0;
  if (currMB->mb_available_up != NULL)
    b = ((currMB->mb_available_up)->cbp > 15) ? 1 : 0;

  a = 0;
  if (currMB->mb_available_left != NULL)
    a = ((currMB->mb_available_left)->cbp > 15) ? 1 : 0;

  curr_cbp_ctx = a+2*b;
  cbp_bit = (cbp > 15 ) ? 1 : 0;
  biari_encode_symbol(eep_dp, (unsigned char) cbp_bit, ctx->cbp_contexts[1] + curr_cbp_ctx );

  if (cbp > 15)
  {
    b = 0;
    if (currMB->mb_available_up != NULL)
      if ((currMB->mb_available_up)->cbp > 15)
        b = (( ((currMB->mb_available_up)->cbp >> 4) == 2) ? 1 : 0);

    a = 0;
    if (currMB->mb_available_left != NULL)
      if ((currMB->mb_available_left)->cbp > 15)
        a = (( ((currMB->mb_available_left)->cbp >> 4) == 2) ? 1 : 0);

    curr_cbp_ctx = a+2*b;
    cbp_bit = ((cbp>>4) == 2) ? 1 : 0;
    biari_encode_symbol(eep_dp, (unsigned char) cbp_bit, ctx->cbp_contexts[2] + curr_cbp_ctx );