cabac.c

H.264编码实现

    else
      act_ctx=5*k+2;
  }

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

  act_sym = iabs(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, (signed short) mv_sign);
  }

  dp->bitstream->write_flag = 1;
  se->len = (arienco_bits_written(eep_dp) - curr_len);
  CABAC_TRACE;
}


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

  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);
  }

  dp->bitstream->write_flag = 1;
  se->len = (arienco_bits_written(eep_dp) - curr_len);
  CABAC_TRACE;
}


/*!
 ****************************************************************************
 * \brief
 *    This function is used to arithmetically encode the coded
 *    block pattern of an 8x8 block
 ****************************************************************************
 */
void writeCBP_BIT_CABAC (Macroblock* currMB, int b8, int bit, int cbp, int inter, EncodingEnvironmentPtr eep_dp, TextureInfoContexts *ctx)
{
  PixelPos block_a;
  int a = 0, b = 0;

  int mb_x=(b8 & 0x01)<<1;
  int mb_y=(b8 >> 1)<<1;

  if (mb_y == 0)
  {
    if (!((currMB->mb_available_up == NULL) || ((currMB->mb_available_up)->mb_type==IPCM)))
    {
      b = (( ((currMB->mb_available_up)->cbp & (1<<(2+(mb_x>>1)))) == 0) ? 1 : 0);   //VG-ADD
    }

  }
  else
    b = ( ((cbp & (1<<(mb_x >> 1))) == 0) ? 1: 0);

  if (mb_x == 0)
  {
    get4x4Neighbour(currMB, (mb_x << 2) - 1, (mb_y << 2), img->mb_size[IS_LUMA], &block_a);

    if (block_a.available && (!(img->mb_data[block_a.mb_addr].mb_type==IPCM)))
    {
      a = (( (img->mb_data[block_a.mb_addr].cbp & (1<<(2*(block_a.y>>1)+1))) == 0) ? 1 : 0); //VG-ADD
    }    
  }
  else
    a = ( ((cbp & (1<<mb_y)) == 0) ? 1: 0);

  //===== WRITE BIT =====
  biari_encode_symbol (eep_dp, (signed short) bit, 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(Macroblock *currMB, SyntaxElement *se, DataPartition *dp)
{
  EncodingEnvironmentPtr eep_dp = &(dp->ee_cabac);
  int curr_len = arienco_bits_written(eep_dp);
  TextureInfoContexts *ctx = img->currentSlice->tex_ctx;

  int a0 = 0, a1 = 0, b0 = 0, b1 = 0;
  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 (currMB, b8, cbp&(1<<b8), cbp, curr_cbp_idx, eep_dp, ctx);
  }

  if ((img->yuv_format != YUV400) && (img->yuv_format != YUV444) )
  {
    // coding of chroma part
    if (currMB->mb_available_up != NULL)
    {
      if((currMB->mb_available_up)->mb_type == IPCM || ((currMB->mb_available_up)->cbp > 15))
        b0 = 2;
    }

    if (currMB->mb_available_left != NULL)
    {
      if((currMB->mb_available_left)->mb_type==IPCM || ((currMB->mb_available_left)->cbp > 15))
        a0 = 1;
    }

    curr_cbp_ctx = a0 + b0;
    cbp_bit = (cbp > 15 ) ? 1 : 0;
    biari_encode_symbol(eep_dp, (signed short) cbp_bit, ctx->cbp_contexts[1] + curr_cbp_ctx );

    if (cbp > 15)
    {
      if (currMB->mb_available_up != NULL)
      {
        if((currMB->mb_available_up)->mb_type==IPCM || 
          (((currMB->mb_available_up)->cbp > 15) && ( ((currMB->mb_available_up)->cbp >> 4) == 2)))
          b1 = 2;
      }

      if (currMB->mb_available_left != NULL)
      {
        if((currMB->mb_available_left)->mb_type==IPCM || 
          (((currMB->mb_available_left)->cbp > 15) && ( ((currMB->mb_available_left)->cbp >> 4) == 2)))
          a1 = 1;
      }

      curr_cbp_ctx = a1 + b1;
      cbp_bit = ((cbp>>4) == 2) ? 1 : 0;
      biari_encode_symbol(eep_dp, (signed short) cbp_bit, ctx->cbp_contexts[2] + curr_cbp_ctx );
    }
  }

  dp->bitstream->write_flag = 1;
  se->len = (arienco_bits_written(eep_dp) - curr_len);
  CABAC_TRACE;
}

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};
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};

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};
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
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
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
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
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

/*!
 ****************************************************************************
 * \brief
 *    Write CBP4-BIT
 ****************************************************************************
 */
void write_and_store_CBP_block_bit (Macroblock* currMB, EncodingEnvironmentPtr eep_dp, int type, int cbp_bit, TextureInfoContexts*  tex_ctx)
{
#define BIT_SET(x,n)  ((int)(((x)&((int64)1<<(n)))>>(n)))

  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 && !img->is_v_block);
  int v_ac        = (type==CHROMA_AC &&  img->is_v_block);
  int chroma_dc   = (type==CHROMA_DC || type==CHROMA_DC_2x4 || type==CHROMA_DC_4x4);
  int u_dc        = (chroma_dc && !img->is_v_block);
  int v_dc        = (chroma_dc &&  img->is_v_block);
  int j           = ((y_ac || u_ac || v_ac ? img->subblock_y : 0) << 2);
  int i           =  (y_ac || u_ac || v_ac ? img->subblock_x : 0);
  int bit         =  (y_dc ? 0 : y_ac ? 1 : u_dc ? 17 : v_dc ? 18 : u_ac ? 19 : 23);
  int default_bit =  (img->is_intra_block ? 1 : 0);
  int upper_bit   = default_bit;
  int left_bit    = default_bit;
  int ctx;

  int bit_pos_a   = 0;
  int bit_pos_b   = 0;

  PixelPos block_a, block_b;

  if (y_ac || y_dc)
  {
    get4x4Neighbour(currMB, (i << 2) - 1, j   , img->mb_size[IS_LUMA], &block_a);
    get4x4Neighbour(currMB, (i << 2),     j -1, img->mb_size[IS_LUMA], &block_b);
    if (y_ac)
    {
      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 << 2) - 1, j    , img->mb_size[IS_CHROMA], &block_a);
    get4x4Neighbour(currMB, (i << 2),     j - 1, img->mb_size[IS_CHROMA], &block_b);
    if (u_ac||v_ac)
    {
      if (block_a.available)
        bit_pos_a = (block_a.y << 2) + block_a.x;
      if (block_b.available)
        bit_pos_b = (block_b.y << 2) + block_b.x;
    }
  }

  bit = (y_dc ? 0 : y_ac ? 1 + j + i : u_dc ? 17 : v_dc ? 18 : u_ac ? 19 + j + i : 35 + j + i);
  //--- set bits for current block ---
  if (cbp_bit)
  {    
    if (type==LUMA_8x8)
    {
      currMB->cbp_bits[0] |= ((int64) 0x33 << bit);

      if (enc_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==LUMA_4x8)
    {      
      currMB->cbp_bits[0]     |= ((int64) 0x11 << 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==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);
    }
  }

  bit = (y_dc ? 0 : y_ac ? 1 : u_dc ? 17 : v_dc ? 18 : u_ac ? 19 : 35);

  if (enc_picture->chroma_format_idc!=YUV444)
  {
    if (type!=LUMA_8x8)
    {
      if (block_b.available)
      {
        if(img->mb_data[block_b.mb_addr].mb_type==IPCM)
          upper_bit = 1;
        else
          upper_bit = BIT_SET(img->mb_data[block_b.mb_addr].cbp_bits[0],bit+bit_pos_b);
      }


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

      ctx = 2 * upper_bit + left_bit;

      //===== encode symbol =====
      biari_encode_symbol (eep_dp, (short)cbp_bit, tex_ctx->bcbp_contexts[type2ctx_bcbp[type]] + ctx);
    }
  }
  else if( IS_INDEPENDENT(params) )
  {
    if (type!=LUMA_8x8)
    {
      if (block_b.available)
      {
        if(img->mb_data[block_b.mb_addr].mb_type==IPCM)
          upper_bit = 1;
        else
          upper_bit = BIT_SET(img->mb_data[block_b.mb_addr].cbp_bits[0],bit+bit_pos_b);
      }


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

      ctx = 2 * upper_bit + left_bit;

      //===== encode symbol =====
      biari_encode_symbol (eep_dp, (short)cbp_bit, tex_ctx->bcbp_contexts[type2ctx_bcbp[type]] + ctx);
    }
  }
  else 
  {
    if (block_b.available)
    {
      if(img->mb_data[block_b.mb_addr].mb_type == IPCM)
        upper_bit=1;
      else
      {
        if(type==LUMA_8x8)
          upper_bit = BIT_SET(img->mb_data[block_b.mb_addr].cbp_bits_8x8[0], bit + bit_pos_b);
        else if (type==CB_8x8)
          upper_bit = BIT_SET(img->mb_data[block_b.mb_addr].cbp_bits_8x8[1], bit + bit_pos_b);
        else if (type==CR_8x8)
          upper_bit = BIT_SET(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 = BIT_SET(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 = BIT_SET(img->mb_data[block_b.mb_addr].cbp_bits[2], bit + bit_pos_b);
        else
          upper_bit = BIT_SET(img->mb_data[block_b.mb_addr].cbp_bits[0], bit + bit_pos_b);
      }
    }

    if (block_a.available)
    {
      if(img->mb_data[block_a.mb_addr].mb_type==IPCM)
        left_bit = 1;
      else
      {
        if(type==LUMA_8x8)
          left_bit = BIT_SET(img->mb_data[block_a.mb_addr].cbp_bits_8x8[0],bit + bit_pos_a);
        else if (type==CB_8x8)
          left_bit = BIT_SET(img->mb_data[block_a.mb_addr].cbp_bits_8x8[1],bit + bit_pos_a);
        else if (type==CR_8x8)
          left_bit = BIT_SET(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 = BIT_SET(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 = BIT_SET(img->mb_data[block_a.mb_addr].cbp_bits[2],bit + bit_pos_a);
        else
          left_bit = BIT_SET(img->mb_data[block_a.mb_addr].cbp_bits[0],bit + bit_pos_a);
      }
    }

    ctx = 2*upper_bit+left_bit;