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revision 195, Wed Jun 12 20:38:41 2002 UTC revision 653, Sun Nov 17 00:41:20 2002 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/dequantization functions -
5   *   *
6   *    This program is an implementation of a part of one or more MPEG-4   *  Copyright(C) 2002 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 file is part of XviD, a free MPEG-4 video encoder/decoder
9   *    it under the terms of the GNU General Public License as published by   *
10     *  XviD is free software; you can redistribute it and/or modify it
11     *  under the terms of the GNU General Public License as published by
12   *    the Free Software Foundation; either version 2 of the License, or   *    the Free Software Foundation; either version 2 of the License, or
13   *    (at your option) any later version.   *    (at your option) any later version.
14   *   *
# Line 24  Line 19 
19   *   *
20   *    You should have received a copy of the GNU General Public License   *    You should have received a copy of the GNU General Public License
21   *    along with this program; if not, write to the Free Software   *    along with this program; if not, write to the Free Software
22   *    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.   *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
23   *   *
24   *************************************************************************/   *  Under section 8 of the GNU General Public License, the copyright
25     *  holders of XVID explicitly forbid distribution in the following
26  /**************************************************************************   *  countries:
27   *   *
28   *    History:   *    - Japan
29     *    - United States of America
30   *   *
31   *      26.01.2002    fixed  quant4_intra dcscalar signed/unsigned error   *  Linking XviD statically or dynamically with other modules is making a
32   *  20.01.2002    increased accuracy of >> divide   *  combined work based on XviD.  Thus, the terms and conditions of the
33   *  26.12.2001    divide-by-multiplication optimization   *  GNU General Public License cover the whole combination.
  *  22.12.2001    [-127,127] clamping removed; minor tweaks  
  *      19.11.2001    inital version <pross@cs.rmit.edu.au>  
34   *   *
35   *************************************************************************/   *  As a special exception, the copyright holders of XviD give you
36     *  permission to link XviD with independent modules that communicate with
37     *  XviD solely through the VFW1.1 and DShow interfaces, regardless of the
38     *  license terms of these independent modules, and to copy and distribute
39     *  the resulting combined work under terms of your choice, provided that
40     *  every copy of the combined work is accompanied by a complete copy of
41     *  the source code of XviD (the version of XviD used to produce the
42     *  combined work), being distributed under the terms of the GNU General
43     *  Public License plus this exception.  An independent module is a module
44     *  which is not derived from or based on XviD.
45     *
46     *  Note that people who make modified versions of XviD are not obligated
47     *  to grant this special exception for their modified versions; it is
48     *  their choice whether to do so.  The GNU General Public License gives
49     *  permission to release a modified version without this exception; this
50     *  exception also makes it possible to release a modified version which
51     *  carries forward this exception.
52     *
53     * $Id: quant_mpeg4.c,v 1.6 2002-11-17 00:41:19 edgomez Exp $
54     *
55     ****************************************************************************/
56    
57  #include "quant_mpeg4.h"  #include "quant_mpeg4.h"
58  #include "quant_matrix.h"  #include "quant_matrix.h"
59    
60  // function pointers  /*****************************************************************************
61     * Function pointers
62     ****************************************************************************/
63    
64  quant_intraFuncPtr quant4_intra;  quant_intraFuncPtr quant4_intra;
65  quant_intraFuncPtr dequant4_intra;  quant_intraFuncPtr dequant4_intra;
66  dequant_interFuncPtr dequant4_inter;  dequant_interFuncPtr dequant4_inter;
67  quant_interFuncPtr quant4_inter;  quant_interFuncPtr quant4_inter;
68    
69    
70    /*****************************************************************************
71     * Local data
72     ****************************************************************************/
73    
74  #define DIV_DIV(A,B)    ( (A) > 0 ? ((A)+((B)>>1))/(B) : ((A)-((B)>>1))/(B) )  #define DIV_DIV(A,B)    ( (A) > 0 ? ((A)+((B)>>1))/(B) : ((A)-((B)>>1))/(B) )
75  #define SIGN(A)  ((A)>0?1:-1)  #define SIGN(A)  ((A)>0?1:-1)
76  #define VM18P    3  #define VM18P    3
77  #define VM18Q    4  #define VM18Q    4
78    
79    
80  // divide-by-multiply table  /*
81  // need 17 bit shift (16 causes slight errors when q > 19)   * divide-by-multiply table
82     * need 17 bit shift (16 causes slight errors when q > 19)
83     */
84    
85  #define SCALEBITS    17  #define SCALEBITS    17
86  #define FIX(X)        ((1UL << SCALEBITS) / (X) + 1)  #define FIX(X)        ((1UL << SCALEBITS) / (X) + 1)
# Line 74  Line 96 
96          FIX(56), FIX(58), FIX(60), FIX(62)          FIX(56), FIX(58), FIX(60), FIX(62)
97  };  };
98    
99    /*****************************************************************************
100     * Functions
101     ****************************************************************************/
102    
103  /*    quantize intra-block  /*    quantize intra-block
104    
105      // const int32_t quantd = DIV_DIV(VM18P*quant, VM18Q);      // const int32_t quantd = DIV_DIV(VM18P*quant, VM18Q);
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