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

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

  act_sym += sign;
  act_sym --;

  act_ctx = ( (last_dquant != 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)
{
  PixelPos block_a;
  int a, b;
  
  int mb_x=(b8%2)<<1;
  int mb_y=(b8/2)<<1;
  
  if (mb_y == 0)
  {
    if (currMB->mb_available_up == NULL)
      b = 0;
    else
    {
      if((currMB->mb_available_up)->mb_type==IPCM)
        b=0;
      else
				b = (( ((currMB->mb_available_up)->cbp & (1<<(2+mb_x/2))) == 0) ? 1 : 0);   //VG-ADD
    }
    
  }
  else
    b = ( ((cbp & (1<<(mb_x/2))) == 0) ? 1: 0);
  
  if (mb_x == 0)
  {
    getLuma4x4Neighbour(img->current_mb_nr, mb_x, mb_y, -1, 0, &block_a);
    if (block_a.available)
    {
      {
        if(img->mb_data[block_a.mb_addr].mb_type==IPCM)
          a=0;
        else
					a = (( (img->mb_data[block_a.mb_addr].cbp & (1<<(2*(block_a.y/2)+1))) == 0) ? 1 : 0); //VG-ADD
      }
      
    }
    else
      a=0;
  }
  else
    a = ( ((cbp & (1<<mb_y)) == 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)
  {
    if((currMB->mb_available_up)->mb_type==IPCM)
      b=1;
    else
      b = ((currMB->mb_available_up)->cbp > 15) ? 1 : 0;
  }


  a = 0;
  if (currMB->mb_available_left != NULL)
  {
    if((currMB->mb_available_left)->mb_type==IPCM)
      a=1;
    else
      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)->mb_type==IPCM)
        b=1;
      else
        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)->mb_type==IPCM)
        a=1;
      else
        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 );
  }
}


static const int maxpos       [] = {16, 15, 64, 32, 32, 16,  4, 15};
static const int c1isdc       [] = { 1,  0,  1,  1,  1,  1,  1,  0};

static const int type2ctx_bcbp[] = { 0,  1,  2,  2,  3,  4,  5,  6}; // 7
static const int type2ctx_map [] = { 0,  1,  2,  3,  4,  5,  6,  7}; // 8
static const int type2ctx_last[] = { 0,  1,  2,  3,  4,  5,  6,  7}; // 8
static const int type2ctx_one [] = { 0,  1,  2,  3,  3,  4,  5,  6}; // 7
static const int type2ctx_abs [] = { 0,  1,  2,  3,  3,  4,  5,  6}; // 7



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

  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 && !img->is_v_block);
  int v_ac        = (type==CHROMA_AC &&  img->is_v_block);
  int u_dc        = (type==CHROMA_DC && !img->is_v_block);
  int v_dc        = (type==CHROMA_DC &&  img->is_v_block);
  int j           = (y_ac || u_ac || v_ac ? img->subblock_y : 0);
  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)
  {
    getLuma4x4Neighbour(img->current_mb_nr, i, j, -1,  0, &block_a);
    getLuma4x4Neighbour(img->current_mb_nr, i, j,  0, -1, &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
  {
    getChroma4x4Neighbour(img->current_mb_nr, i, j, -1,  0, &block_a);
    getChroma4x4Neighbour(img->current_mb_nr, i, j,  0, -1, &block_b);
    if (u_ac||v_ac)
    {
      if (block_a.available)
        bit_pos_a = 2*block_a.y + block_a.x;
      if (block_b.available)
        bit_pos_b = 2*block_b.y + block_b.x;
    }
  }

  bit         = (y_dc ? 0 : y_ac ? 1+4*j+i : u_dc ? 17 : v_dc ? 18 : u_ac ? 19+2*j+i : 23+2*j+i);
  //--- set bits for current block ---
  if (cbp_bit)
  {
    if (type==LUMA_8x8)
    {
      currMB->cbp_bits   |= (1<< bit   );
      currMB->cbp_bits   |= (1<<(bit+1));
      currMB->cbp_bits   |= (1<<(bit+4));
      currMB->cbp_bits   |= (1<<(bit+5));
    }
    else if (type==LUMA_8x4)
    {
      currMB->cbp_bits   |= (1<< bit   );
      currMB->cbp_bits   |= (1<<(bit+1));
    }
    else if (type==LUMA_4x8)
    {
      currMB->cbp_bits   |= (1<< bit   );
      currMB->cbp_bits   |= (1<<(bit+4));
    }
    else
    {
      currMB->cbp_bits   |= (1<<bit);
    }
  }

  bit         = (y_dc ? 0 : y_ac ? 1 : u_dc ? 17 : v_dc ? 18 : u_ac ? 19 : 23);
  if (type!=LUMA_8x8)
  {
    if (block_b.available)
    {
      if(img->mb_data[block_b.mb_addr].mb_type==IPCM)
        upper_bit=1;