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revision 653, Sun Nov 17 00:41:20 2002 UTC revision 851, Sat Feb 15 15:22:19 2003 UTC
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1  /*****************************************************************************  /**************************************************************************
2   *   *
3   *  XVID MPEG-4 VIDEO CODEC   *  XVID MPEG-4 VIDEO CODEC
4   *  - Mpeg4 quantization/dequantization functions -   *    mpeg-4 quantization/dequantization
5   *   *
6   *  Copyright(C) 2002 Peter Ross <pross@xvid.org>   *    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
8     *    to use this software module in hardware or software products are
9     *    advised that its use may infringe existing patents or copyrights, and
10     *    any such use would be at such party's own risk.  The original
11     *    developer of this software module and his/her company, and subsequent
12     *    editors and their companies, will have no liability for use of this
13     *    software or modifications or derivatives thereof.
14   *   *
15   *  This file is part of XviD, a free MPEG-4 video encoder/decoder   *    This program is free software; you can redistribute it and/or modify
16   *   *    it under the terms of the GNU General Public License as published by
  *  XviD is free software; you can redistribute it and/or modify it  
  *  under the terms of the GNU General Public License as published by  
17   *  the Free Software Foundation; either version 2 of the License, or   *  the Free Software Foundation; either version 2 of the License, or
18   *  (at your option) any later version.   *  (at your option) any later version.
19   *   *
# Line 19  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.
  *  
  *  Under section 8 of the GNU General Public License, the copyright  
  *  holders of XVID explicitly forbid distribution in the following  
  *  countries:  
  *  
  *    - Japan  
  *    - United States of America  
28   *   *
29   *  Linking XviD statically or dynamically with other modules is making a   *************************************************************************/
30   *  combined work based on XviD.  Thus, the terms and conditions of the  
31   *  GNU General Public License cover the whole combination.  /**************************************************************************
  *  
  *  As a special exception, the copyright holders of XviD give you  
  *  permission to link XviD with independent modules that communicate with  
  *  XviD solely through the VFW1.1 and DShow interfaces, regardless of the  
  *  license terms of these independent modules, and to copy and distribute  
  *  the resulting combined work under terms of your choice, provided that  
  *  every copy of the combined work is accompanied by a complete copy of  
  *  the source code of XviD (the version of XviD used to produce the  
  *  combined work), being distributed under the terms of the GNU General  
  *  Public License plus this exception.  An independent module is a module  
  *  which is not derived from or based on XviD.  
32   *   *
33   *  Note that people who make modified versions of XviD are not obligated   *    History:
  *  to grant this special exception for their modified versions; it is  
  *  their choice whether to do so.  The GNU General Public License gives  
  *  permission to release a modified version without this exception; this  
  *  exception also makes it possible to release a modified version which  
  *  carries forward this exception.  
34   *   *
35   * $Id: quant_mpeg4.c,v 1.6 2002-11-17 00:41:19 edgomez Exp $   *      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    
57    
58  /*  // divide-by-multiply table
59   * divide-by-multiply table  // need 17 bit shift (16 causes slight errors when q > 19)
  * need 17 bit shift (16 causes slight errors when q > 19)  
  */  
60    
61  #define SCALEBITS    17  #define SCALEBITS    17
62  #define FIX(X)        ((1UL << SCALEBITS) / (X) + 1)  #define FIX(X)        ((1UL << SCALEBITS) / (X) + 1)
# Line 96  Line 72 
72          FIX(56), FIX(58), FIX(60), FIX(62)          FIX(56), FIX(58), FIX(60), FIX(62)
73  };  };
74    
 /*****************************************************************************  
  * Functions  
  ****************************************************************************/  
   
75  /*    quantize intra-block  /*    quantize intra-block
76    
77      // const int32_t quantd = DIV_DIV(VM18P*quant, VM18Q);      // const int32_t quantd = DIV_DIV(VM18P*quant, VM18Q);
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