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Diff of /xvidcore/src/quant/quant_mpeg4.c

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revision 1.4, Sat Sep 7 11:21:10 2002 UTC revision 1.9.2.1, Mon Jun 9 01:24:55 2003 UTC
# Line 1  Line 1 
1  /*****************************************************************************  /**************************************************************************
2   *   *
3   *  XVID MPEG-4 VIDEO CODEC   *  XVID MPEG-4 VIDEO CODEC
4   *  - Mpeg4 quantization/dequantization functions -   *    mpeg-4 quantization/dequantization
  *  
  *  Copyright(C) 2002 Peter Ross  
5   *   *
6   *  This program is an implementation of a part of one or more MPEG-4   *  This program is an implementation of a part of one or more MPEG-4
7   *  Video tools as specified in ISO/IEC 14496-2 standard.  Those intending   *  Video tools as specified in ISO/IEC 14496-2 standard.  Those intending
# Line 26  Line 24 
24   *   *
25   *  You should have received a copy of the GNU General Public License   *  You should have received a copy of the GNU General Public License
26   *  along with this program ; if not, write to the Free Software   *  along with this program ; if not, write to the Free Software
27   *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA   *    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
28     *
29     *************************************************************************/
30    
31    /**************************************************************************
32     *
33     *    History:
34   *   *
35   *  $Id$   *      26.01.2002    fixed  quant4_intra dcscalar signed/unsigned error
36     *  20.01.2002    increased accuracy of >> divide
37     *  26.12.2001    divide-by-multiplication optimization
38     *  22.12.2001    [-127,127] clamping removed; minor tweaks
39     *      19.11.2001    inital version <pross@cs.rmit.edu.au>
40   *   *
41   ****************************************************************************/   *************************************************************************/
42    
43    #include "../global.h"
44  #include "quant_mpeg4.h"  #include "quant_mpeg4.h"
45  #include "quant_matrix.h"  #include "quant_matrix.h"
46    
47  /*****************************************************************************  /* function pointers */
  * Function pointers  
  ****************************************************************************/  
   
48  quant_intraFuncPtr quant4_intra;  quant_intraFuncPtr quant4_intra;
49  quant_intraFuncPtr dequant4_intra;  quant_intraFuncPtr dequant4_intra;
50  dequant_interFuncPtr dequant4_inter;  dequant_interFuncPtr dequant4_inter;
51  quant_interFuncPtr quant4_inter;  quant_interFuncPtr quant4_inter;
52    
53    
 /*****************************************************************************  
  * Local data  
  ****************************************************************************/  
   
 #define DIV_DIV(A,B)    ( (A) > 0 ? ((A)+((B)>>1))/(B) : ((A)-((B)>>1))/(B) )  
 #define SIGN(A)  ((A)>0?1:-1)  
54  #define VM18P    3  #define VM18P    3
55  #define VM18Q    4  #define VM18Q    4
56    
# Line 74  Line 74 
74          FIX(56), FIX(58), FIX(60), FIX(62)          FIX(56), FIX(58), FIX(60), FIX(62)
75  };  };
76    
 /*****************************************************************************  
  * Functions  
  ****************************************************************************/  
   
77  /*    quantize intra-block  /*    quantize intra-block
78     *
79      // const int32_t quantd = DIV_DIV(VM18P*quant, VM18Q);   * const int32_t quantd = DIV_DIV(VM18P*quant, VM18Q);
80      //   * level = DIV_DIV(16 * data[i], default_intra_matrix[i]);
81      // level = DIV_DIV(16 * data[i], default_intra_matrix[i]);   * coeff[i] = (level + quantd) / quant2;
     // coeff[i] = (level + quantd) / quant2;  
82  */  */
83    
84  void  void
# Line 122  Line 117 
117    
118    
119    
120  /*    dequantize intra-block & clamp to [-2048,2047]  /*
121      // data[i] = (coeff[i] * default_intra_matrix[i] * quant2) >> 4;   * dequantize intra-block & clamp to [-2048,2047]
122     *
123     * data[i] = (coeff[i] * default_intra_matrix[i] * quant2) >> 4;
124  */  */
125    
126  void  void
# Line 152  Line 149 
149    
150                          level = (level * intra_matrix[i] * quant) >> 3;                          level = (level * intra_matrix[i] * quant) >> 3;
151                          data[i] = (level <= 2048 ? -(int16_t) level : -2048);                          data[i] = (level <= 2048 ? -(int16_t) level : -2048);
152                  } else                                  // if (coeff[i] > 0)                  } else                                  /* if (coeff[i] > 0) */
153                  {                  {
154                          uint32_t level = coeff[i];                          uint32_t level = coeff[i];
155    
# Line 165  Line 162 
162    
163    
164  /*    quantize inter-block  /*    quantize inter-block
165     *
166      // level = DIV_DIV(16 * data[i], default_intra_matrix[i]);   * level = DIV_DIV(16 * data[i], default_intra_matrix[i]);
167      // coeff[i] = (level + quantd) / quant2;   * coeff[i] = (level + quantd) / quant2;
168      // sum += abs(level);   * sum += abs(level);
169  */  */
170    
171  uint32_t  uint32_t
# Line 230  Line 227 
227    
228                          level = ((2 * level + 1) * inter_matrix[i] * quant) >> 4;                          level = ((2 * level + 1) * inter_matrix[i] * quant) >> 4;
229                          data[i] = (level <= 2048 ? -level : -2048);                          data[i] = (level <= 2048 ? -level : -2048);
230                  } else                                  // if (coeff[i] > 0)                  } else                                  /* if (coeff[i] > 0) */
231                  {                  {
232                          uint32_t level = coeff[i];                          uint32_t level = coeff[i];
233    
# Line 241  Line 238 
238                  sum ^= data[i];                  sum ^= data[i];
239          }          }
240    
241          // mismatch control          /*  mismatch control */
242    
243          if ((sum & 1) == 0) {          if ((sum & 1) == 0) {
244                  data[63] ^= 1;                  data[63] ^= 1;
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