cabac.c

h.264/avc 视频编码程序,实现分数像素匹配功能,非原创.

      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 if (act_sym==12)
    {
      biari_encode_symbol (eep_dp, 1, &ctx->b8_type_contexts[1][1]);
      biari_encode_symbol (eep_dp, 1, &ctx->b8_type_contexts[1][2]);
      biari_encode_symbol (eep_dp, 1, &ctx->b8_type_contexts[1][3]);
      biari_encode_symbol (eep_dp, 1, &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]);
      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 writeIntraPredMode2Buffer_CABAC(SyntaxElement *se, EncodingEnvironmentPtr eep_dp)
{
  static const int    right[8] = {0, 0, 1, 1, 0, 0, 1, 1};
  Macroblock          *currMB  = &(img->mb_data[img->current_mb_nr]);
  TextureInfoContexts *ctx     = img->currentSlice->tex_ctx;
  int                 prev_sym; 
 
  //--- first symbol ---
  if (right[se->context/2])             prev_sym = currMB->intra_pred_modes[se->context-3];
  else if (currMB->mb_available[1][0])  prev_sym = currMB->mb_available[1][0]->intra_pred_modes[se->context+5];
  else                                  prev_sym = 0;

#ifndef USE_6_INTRA_MODES
  unary_bin_max_encode(eep_dp,(unsigned int) se->value1,ctx->ipr_contexts[prev_sym],1,8);
#else
  unary_bin_max_encode(eep_dp,(unsigned int) se->value1,ctx->ipr_contexts[prev_sym],1,5);
#endif

  //--- second symbol ---
  prev_sym = se->value1;
#ifndef USE_6_INTRA_MODES
  unary_bin_max_encode(eep_dp,(unsigned int) se->value2,ctx->ipr_contexts[prev_sym],1,8);
#else
  unary_bin_max_encode(eep_dp,(unsigned int) se->value2,ctx->ipr_contexts[prev_sym],1,5);
#endif
}


/*!
 ****************************************************************************
 * \brief
 *    This function is used to arithmetically encode the reference
 *    parameter of a given MB.
 ****************************************************************************
 */
void writeRefFrame2Buffer_CABAC(SyntaxElement *se, EncodingEnvironmentPtr eep_dp)
{
  MotionInfoContexts  *ctx    = img->currentSlice->mot_ctx;
  Macroblock          *currMB = &img->mb_data[img->current_mb_nr];
  int                 addctx  = se->context;

  int   a, b;
  int   act_ctx;
  int   act_sym;
  int** refframe_array = (img->type==B_IMG ? fw_refFrArr : refFrArr);

  if (currMB->mb_available[0][1] == NULL)
    b = 0;
  else
    b = (refframe_array[img->block_y+img->subblock_y-1][img->block_x+img->subblock_x] > 0 ? 1 : 0);
  if (currMB->mb_available[1][0] == NULL)
    a = 0;
  else 
    a = (refframe_array[img->block_y+img->subblock_y][img->block_x+img->subblock_x-1] > 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 motion
 *    vector data of a given MB.
 ****************************************************************************
 */
void writeMVD2Buffer_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 k = se->value2; // MVD component

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

  if (j==0)
  {
    if (currMB->mb_available[0][1] == NULL)
      b = 0;
    else 
      b = absm((currMB->mb_available[0][1])->mvd[0][BLOCK_SIZE-1][i][k]);
  }
  else
    b = absm(currMB->mvd[0][j-1][i][k]);
          
  if (i==0)
  {
    if (currMB->mb_available[1][0] == NULL)
      a = 0;
    else 
      a = absm((currMB->mb_available[1][0])->mvd[0][j][BLOCK_SIZE-1][k]);
  }
  else
    a = absm(currMB->mvd[0][j][i-1][k]);

  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] );
    mv_sign = (mv_pred_res<0) ? 1: 0;
    act_ctx=5*k+4;
    biari_encode_symbol(eep_dp, (unsigned char) mv_sign, &ctx->mv_res_contexts[1][act_ctx] );
    act_sym--;
    act_ctx=5*k;
    unary_mv_encode(eep_dp,act_sym,ctx->mv_res_contexts[1]+act_ctx,3);
  }
}


/*!
 ****************************************************************************
 * \brief
 *    This function is used to arithmetically encode the coded
 *    block pattern of a given delta quant.
 ****************************************************************************
 */
void writeDquant_inter_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[1][0] == NULL)
    act_ctx = 0;
  else
    act_ctx = ( ((currMB->mb_available[1][0])->delta_qp != 0) ? 1 : 0);

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


/*!
 ****************************************************************************
 * \brief
 *    This function is used to arithmetically encode the coded
 *    block pattern of a given delta quant.
 ****************************************************************************
 */
void writeDquant_intra_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[1][0] == NULL)
    act_ctx = 0;
  else
    act_ctx = ( ((currMB->mb_available[1][0])->delta_qp != 0) ? 1 : 0);

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


/*!
 ****************************************************************************
 * \brief
 *    This function is used to arithmetically encode the motion
 *    vector data of a B-frame MB.
 ****************************************************************************
 */
void writeBiMVD2Buffer_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 backward = se->value2 & 0x01;
  int k = (se->value2>>1); // MVD component

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

  if (j==0)
  {
    if (currMB->mb_available[0][1] == NULL)
      b = 0;
    else
      b = absm((currMB->mb_available[0][1])->mvd[backward][BLOCK_SIZE-1][i][k]);
  }
  else
    b = absm(currMB->mvd[backward][j-1][i][k]);

  if (i==0)
  {
    if (currMB->mb_available[1][0] == NULL)
      a = 0;
    else
      a = absm((currMB->mb_available[1][0])->mvd[backward][j][BLOCK_SIZE-1][k]);
  }
  else
    a = absm(currMB->mvd[backward][j][i-1][k]);

  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] );
    mv_sign = (mv_pred_res<0) ? 1: 0;
    act_ctx=5*k+4;
    biari_encode_symbol(eep_dp, (unsigned char) mv_sign, &ctx->mv_res_contexts[1][act_ctx] );
    act_sym--;
    act_ctx=5*k;
    unary_mv_encode(eep_dp,act_sym,ctx->mv_res_contexts[1]+act_ctx,3);
  }
}


/*!
 ****************************************************************************
 * \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[0][1] == NULL)
      b = 0;
    else
      b = ((currMB->mb_available[0][1]->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[1][0] == NULL)
      a = 0;
    else
      a = ((currMB->mb_available[1][0]->cbp & (1<<(b8+1))) == 0 ? 1 : 0);
  }
  else
    a   = ((cbp & (1<<(b8-1))) == 0 ? 1: 0);