quant4x4_around.c

H.264编码实现

/*!
 *************************************************************************************
 * \file quant4x4.c
 *
 * \brief
 *    Quantization process for a 4x4 block
 *
 * \author
 *    Main contributors (see contributors.h for copyright, address and affiliation details)
 *    - Alexis Michael Tourapis                  <[e-mail]>
 *    - Limin Liu                                <[e-mail]>
 *
 *************************************************************************************
 */

#include "contributors.h"

#include <math.h>

#include "global.h"

#include "image.h"
#include "mb_access.h"
#include "vlc.h"
#include "transform.h"
#include "mc_prediction.h"
#include "q_offsets.h"
#include "q_matrix.h"
#include "quant4x4.h"


/*!
 ************************************************************************
 * \brief
 *    Quantization process for All coefficients for a 4x4 block
 *
 * \par Input:
 *
 * \par Output:
 *
 ************************************************************************
 */
int quant_4x4_around(int (*tblock)[16], int block_y, int block_x, int  qp,                 
                     int*  ACLevel, int*  ACRun, 
                     int **fadjust4x4, int **levelscale, int **invlevelscale, int **leveloffset,
                     int *coeff_cost, const byte (*pos_scan)[2], const byte *c_cost, int is_cavlc)
{
  static int i,j, coeff_ctr;

  static int *m7;
  static int scaled_coeff;

  int   level, run = 0;
  int   nonzero = FALSE;
  int   qp_per = qp_per_matrix[qp];
  int   q_bits = Q_BITS + qp_per;
  const byte *p_scan = &pos_scan[0][0];
  int*  ACL = &ACLevel[0];
  int*  ACR = &ACRun[0];

  // Quantization
  for (coeff_ctr = 0; coeff_ctr < 16; coeff_ctr++)
  {
    i = *p_scan++;  // horizontal position
    j = *p_scan++;  // vertical position

    m7 = &tblock[j][block_x + i];

    if (*m7 != 0)
    {
      scaled_coeff = iabs (*m7) * levelscale[j][i];
      level = (scaled_coeff + leveloffset[j][i]) >> q_bits;

      if (level != 0)
      {
        if (is_cavlc)
          level = imin(level, CAVLC_LEVEL_LIMIT);

        fadjust4x4[j][block_x + i] = rshift_rnd_sf((AdaptRndWeight * (scaled_coeff - (level << q_bits))), q_bits + 1);

        *coeff_cost += (level > 1) ? MAX_VALUE : c_cost[run];

        level   = isignab(level, *m7);
        *m7     = rshift_rnd_sf(((level * invlevelscale[j][i]) << qp_per), 4);
        // inverse scale can be alternative performed as follows to ensure 16bit
        // arithmetic is satisfied.
        // *m7 = (qp_per<4) ? rshift_rnd_sf((level*invlevelscale[j][i]),4-qp_per) : (level*invlevelscale[j][i])<<(qp_per-4);
        *ACL++  = level;
        *ACR++  = run; 
        // reset zero level counter
        run     = 0;
        nonzero = TRUE;        
      }
      else
      {
        fadjust4x4[j][block_x + i] = 0;
        run++;
        *m7 = 0;
      } 
    }
    else
    {
      fadjust4x4[j][block_x + i] = 0;
      run++;
    } 
  }

  *ACL = 0;

  return nonzero;
}

int quant_ac4x4_around(int (*tblock)[16], int block_y, int block_x, int qp,
                       int*  ACLevel, int*  ACRun, 
                       int **fadjust4x4, int **levelscale, int **invlevelscale, int **leveloffset,
                       int *coeff_cost, const byte (*pos_scan)[2], const byte *c_cost, int type, int is_cavlc)
{
  static int i,j, coeff_ctr;

  static int *m7;
  static int scaled_coeff;

  int   level, run = 0;
  int   nonzero = FALSE;  
  int   qp_per = qp_per_matrix[qp];
  int   q_bits = Q_BITS + qp_per;
  const byte *p_scan = &pos_scan[1][0];
  int*  ACL = &ACLevel[0];
  int*  ACR = &ACRun[0];

  // Quantization
  for (coeff_ctr = 1; coeff_ctr < 16; coeff_ctr++)
  {
    i = *p_scan++;  // horizontal position
    j = *p_scan++;  // vertical position

    m7 = &tblock[j][block_x + i];
    if (*m7 != 0)
    {
      scaled_coeff = iabs (*m7) * levelscale[j][i];
      level = (scaled_coeff + leveloffset[j][i]) >> q_bits;

      if (level != 0)
      {
        if (is_cavlc)
          level = imin(level, CAVLC_LEVEL_LIMIT);

        fadjust4x4[j][block_x + i] = rshift_rnd_sf((AdaptRndWeight * (scaled_coeff - (level << q_bits))), (q_bits + 1));

        *coeff_cost += (level > 1) ? MAX_VALUE : c_cost[run];

        level  = isignab(level, *m7);
        *m7    = rshift_rnd_sf(((level * invlevelscale[j][i]) << qp_per), 4);
        // inverse scale can be alternative performed as follows to ensure 16bit
        // arithmetic is satisfied.
        // *m7 = (qp_per<4) ? rshift_rnd_sf((level*invlevelscale[j][i]),4-qp_per) : (level*invlevelscale[j][i])<<(qp_per-4);
        *ACL++  = level;
        *ACR++  = run; 
        // reset zero level counter
        run     = 0;
        nonzero = TRUE;
      }
      else
      {
        fadjust4x4[j][block_x + i] = 0;
        run++;
        *m7 = 0;
      }
    }
    else
    {
      fadjust4x4[j][block_x + i] = 0;
      run++;
    }          
  }

  *ACL = 0;

  return nonzero;
}
 
/*!
 ************************************************************************
 * \brief
 *    Quantization process for All coefficients for a 4x4 DC block
 *
 * \par Input:
 *
 * \par Output:
 *
 ************************************************************************
 */
int quant_dc4x4_around(int (*tblock)[4], int qp, int* DCLevel, int* DCRun, 
                       int levelscale, int invlevelscale, int leveloffset, const byte (*pos_scan)[2], int is_calvc)
{
  static int i,j, coeff_ctr;

  static int *m7;
  static int scaled_coeff;

  int   level, run = 0;
  int   nonzero = FALSE;  
  int   qp_per = qp_per_matrix[qp];
  int   q_bits = Q_BITS + qp_per + 1;
  const byte *p_scan = &pos_scan[0][0];
  int*  DCL = &DCLevel[0];
  int*  DCR = &DCRun[0];

  // Quantization
  for (coeff_ctr = 0; coeff_ctr < 16; coeff_ctr++)
  {
    i = *p_scan++;  // horizontal position
    j = *p_scan++;  // vertical position

    m7 = &tblock[j][i];

    if (*m7 != 0)
    {    
      scaled_coeff = iabs (*m7) * levelscale;
      level = (scaled_coeff + (leveloffset << 1) ) >> q_bits;

      if (level != 0)
      {
        if (is_calvc)
          level = imin(level, CAVLC_LEVEL_LIMIT);

        level   = isignab(level, *m7);
        *m7     = level;
        *DCL++  = level;
        *DCR++  = run;
        // reset zero level counter
        run     = 0;
        nonzero = TRUE;
      }
      else
      {
        run++;
        *m7 = 0;
      }
    }
    else
    {
      run++;
    }                    
  }

  *DCL = 0;

  return nonzero;
}