hvirtual/quicktime/decore50/mp4_iquant.c

   1 /**************************************************************************
   2  *                                                                        *
   3  * This code has been developed by Andrea Graziani. This software is an   *
   4  * implementation of a part of one or more MPEG-4 Video tools as          *
   5  * specified in ISO/IEC 14496-2 standard.  Those intending to use this    *
   6  * software module in hardware or software products are advised that its  *
   7  * use may infringe existing patents or copyrights, and any such use      *
   8  * would be at such party's own risk.  The original developer of this     *
   9  * software module and his/her company, and subsequent editors and their  *
  10  * companies (including Project Mayo), will have no liability for use of  *
  11  * this software or modifications or derivatives thereof.                 *
  12  *                                                                        *
  13  * Project Mayo gives users of the Codec a license to this software       *
  14  * module or modifications thereof for use in hardware or software        *
  15  * products claiming conformance to the MPEG-4 Video Standard as          *
  16  * described in the Open DivX license.                                    *
  17  *                                                                        *
  18  * The complete Open DivX license can be found at                         *
  19  * http://www.projectmayo.com/opendivx/license.php                        *
  20  *                                                                        *
  21  **************************************************************************/
  22 /**
  23 *  Copyright (C) 2001 - Project Mayo
  24  *
  25  * Andrea Graziani (Ag)
  26  *
  27  * DivX Advanced Research Center <darc@projectmayo.com>
  28 *
  29 **/
  30 // mp4_iquant.c //
  31
  32 #include "mp4_vars.h"
  33
  34 #include "mp4_predict.h"
  35 #include "mp4_iquant.h"
  36
  37 /**
  38  *      inverse quantization for intra blocks
  39 **/
  40
  41 #define _iquant_h263(coeff, q_2scale, q_add) \
  42 if ((coeff) > 0) \
  43 {       \
  44         (coeff) = ((q_2scale) * (coeff)) + (q_add);     \
  45 }       \
  46 else \
  47 if ((coeff) < 0)\
  48 {       \
  49         (coeff) *= -1;  \
  50         (coeff) = ((q_2scale) * (coeff)) + (q_add);     \
  51         (coeff) *= -1; \
  52 }       \
  53
  54 /**
  55  *
  56 **/
  57
  58 // iquant type h.263, not optimized
  59 // intraFlag is 0 or 1
  60 __inline void iquant (short * psblock, int intraFlag)
  61 {
  62         int i;
  63         int q_scale = mp4_state->hdr.quantizer;
  64         int q_2scale = q_scale << 1;
  65         int q_add = (q_scale & 1) ? q_scale : (q_scale - 1);
  66 /*
  67  * static int count = 0;
  68  * count++;
  69  * if(!(count % 1000))
  70  * {
  71  *      printf("iquant %d\n", count);
  72  * }
  73  */
  74
  75         if(intraFlag)
  76                 for (i = 1; i < 64; i++)
  77                 {
  78                         _iquant_h263(psblock[i], q_2scale, q_add);
  79                 }
  80         else
  81                 for (i = 0; i < 64; i++)
  82                 {
  83                         _iquant_h263(psblock[i], q_2scale, q_add);
  84                 }
  85 }
  86
  87
  88 void iquant_typefirst (short * psblock)
  89 {
  90         int i;
  91 /*
  92  * static int count = 0;
  93  * count++;
  94  * if(!(count % 1000))
  95  * {
  96  *      printf("iquant_typefirst %d\n", count);
  97  * }
  98  */
  99
 100         for (i = 1; i < 64; i++)
 101         {
 102                 if (psblock[i] != 0) {
 103                         psblock[i] = (psblock[i] * 2 *  mp4_state->hdr.quantizer *
 104                                 mp4_tables->intra_quant_matrix[mp4_tables->zig_zag_scan[i]]) >> 4;
 105                 }
 106         }
 107 }
 108
 109