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

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revision 1.9, Sat Feb 15 15:22:19 2003 UTC revision 1.9.2.2, Mon Jun 9 13:55:25 2003 UTC
# Line 1  Line 1 
1  /**************************************************************************  /*****************************************************************************
2   *   *
3   *    XVID MPEG-4 VIDEO CODEC   *    XVID MPEG-4 VIDEO CODEC
4   *    mpeg-4 quantization/dequantization   *  - MPEG4 Quantization related header  -
5   *   *
6   *    This program is an implementation of a part of one or more MPEG-4   *  Copyright(C) 2001-2003 Peter Ross <pross@xvid.org>
  *    Video tools as specified in ISO/IEC 14496-2 standard.  Those intending  
  *    to use this software module in hardware or software products are  
  *    advised that its use may infringe existing patents or copyrights, and  
  *    any such use would be at such party's own risk.  The original  
  *    developer of this software module and his/her company, and subsequent  
  *    editors and their companies, will have no liability for use of this  
  *    software or modifications or derivatives thereof.  
7   *   *
8   *    This program is free software; you can redistribute it and/or modify   *    This program is free software; you can redistribute it and/or modify
9   *    it under the terms of the GNU General Public License as published by   *    it under the terms of the GNU General Public License as published by
# Line 24  Line 17 
17   *   *
18   *    You should have received a copy of the GNU General Public License   *    You should have received a copy of the GNU General Public License
19   *    along with this program; if not, write to the Free Software   *    along with this program; if not, write to the Free Software
20   *    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.   *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
21   *   *
22   *************************************************************************/   * $Id$
   
 /**************************************************************************  
  *  
  *    History:  
  *  
  *      26.01.2002    fixed  quant4_intra dcscalar signed/unsigned error  
  *  20.01.2002    increased accuracy of >> divide  
  *  26.12.2001    divide-by-multiplication optimization  
  *  22.12.2001    [-127,127] clamping removed; minor tweaks  
  *      19.11.2001    inital version <pross@cs.rmit.edu.au>  
23   *   *
24   *************************************************************************/   ****************************************************************************/
25    
26  #include "../global.h"  #include "../global.h"
27  #include "quant_mpeg4.h"  #include "quant_mpeg4.h"
28  #include "quant_matrix.h"  #include "quant_matrix.h"
29    
30  // function pointers  /* function pointers */
31  quant_intraFuncPtr quant4_intra;  quant_intraFuncPtr quant4_intra;
32  quant_intraFuncPtr dequant4_intra;  quant_intraFuncPtr dequant4_intra;
33  dequant_interFuncPtr dequant4_inter;  dequant_interFuncPtr dequant4_inter;
# Line 55  Line 38 
38  #define VM18Q    4  #define VM18Q    4
39    
40    
41  // divide-by-multiply table  /*
42  // need 17 bit shift (16 causes slight errors when q > 19)   * divide-by-multiply table
43     * need 17 bit shift (16 causes slight errors when q > 19)
44     */
45    
46  #define SCALEBITS    17  #define SCALEBITS    17
47  #define FIX(X)        ((1UL << SCALEBITS) / (X) + 1)  #define FIX(X)        ((1UL << SCALEBITS) / (X) + 1)
# Line 73  Line 58 
58  };  };
59    
60  /*    quantize intra-block  /*    quantize intra-block
61     *
62      // const int32_t quantd = DIV_DIV(VM18P*quant, VM18Q);   * const int32_t quantd = DIV_DIV(VM18P*quant, VM18Q);
63      //   * level = DIV_DIV(16 * data[i], default_intra_matrix[i]);
64      // level = DIV_DIV(16 * data[i], default_intra_matrix[i]);   * coeff[i] = (level + quantd) / quant2;
     // coeff[i] = (level + quantd) / quant2;  
65  */  */
66    
67  void  void
# Line 116  Line 100 
100    
101    
102    
103  /*    dequantize intra-block & clamp to [-2048,2047]  /*
104      // data[i] = (coeff[i] * default_intra_matrix[i] * quant2) >> 4;   * dequantize intra-block & clamp to [-2048,2047]
105     *
106     * data[i] = (coeff[i] * default_intra_matrix[i] * quant2) >> 4;
107  */  */
108    
109  void  void
# Line 146  Line 132 
132    
133                          level = (level * intra_matrix[i] * quant) >> 3;                          level = (level * intra_matrix[i] * quant) >> 3;
134                          data[i] = (level <= 2048 ? -(int16_t) level : -2048);                          data[i] = (level <= 2048 ? -(int16_t) level : -2048);
135                  } else                                  // if (coeff[i] > 0)                  } else                                  /* if (coeff[i] > 0) */
136                  {                  {
137                          uint32_t level = coeff[i];                          uint32_t level = coeff[i];
138    
# Line 159  Line 145 
145    
146    
147  /*    quantize inter-block  /*    quantize inter-block
148     *
149      // level = DIV_DIV(16 * data[i], default_intra_matrix[i]);   * level = DIV_DIV(16 * data[i], default_intra_matrix[i]);
150      // coeff[i] = (level + quantd) / quant2;   * coeff[i] = (level + quantd) / quant2;
151      // sum += abs(level);   * sum += abs(level);
152  */  */
153    
154  uint32_t  uint32_t
# Line 224  Line 210 
210    
211                          level = ((2 * level + 1) * inter_matrix[i] * quant) >> 4;                          level = ((2 * level + 1) * inter_matrix[i] * quant) >> 4;
212                          data[i] = (level <= 2048 ? -level : -2048);                          data[i] = (level <= 2048 ? -level : -2048);
213                  } else                                  // if (coeff[i] > 0)                  } else                                  /* if (coeff[i] > 0) */
214                  {                  {
215                          uint32_t level = coeff[i];                          uint32_t level = coeff[i];
216    
# Line 235  Line 221 
221                  sum ^= data[i];                  sum ^= data[i];
222          }          }
223    
224          // mismatch control          /*  mismatch control */
225    
226          if ((sum & 1) == 0) {          if ((sum & 1) == 0) {
227                  data[63] ^= 1;                  data[63] ^= 1;
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