vp8/common/quant_common.c

   1 /*
   2  *  Copyright (c) 2010 The WebM project authors. All Rights Reserved.
   3  *
   4  *  Use of this source code is governed by a BSD-style license
   5  *  that can be found in the LICENSE file in the root of the source
   6  *  tree. An additional intellectual property rights grant can be found
   7  *  in the file PATENTS.  All contributing project authors may
   8  *  be found in the AUTHORS file in the root of the source tree.
   9  */
  10
  11
  12 #include "quant_common.h"
  13
  14 static const int dc_qlookup[QINDEX_RANGE] =
  15 {
  16     4,    5,    6,    7,    8,    9,   10,   10,   11,   12,   13,   14,   15,   16,   17,   17,
  17     18,   19,   20,   20,   21,   21,   22,   22,   23,   23,   24,   25,   25,   26,   27,   28,
  18     29,   30,   31,   32,   33,   34,   35,   36,   37,   37,   38,   39,   40,   41,   42,   43,
  19     44,   45,   46,   46,   47,   48,   49,   50,   51,   52,   53,   54,   55,   56,   57,   58,
  20     59,   60,   61,   62,   63,   64,   65,   66,   67,   68,   69,   70,   71,   72,   73,   74,
  21     75,   76,   76,   77,   78,   79,   80,   81,   82,   83,   84,   85,   86,   87,   88,   89,
  22     91,   93,   95,   96,   98,  100,  101,  102,  104,  106,  108,  110,  112,  114,  116,  118,
  23     122,  124,  126,  128,  130,  132,  134,  136,  138,  140,  143,  145,  148,  151,  154,  157,
  24 };
  25
  26 static const int ac_qlookup[QINDEX_RANGE] =
  27 {
  28     4,    5,    6,    7,    8,    9,   10,   11,   12,   13,   14,   15,   16,   17,   18,   19,
  29     20,   21,   22,   23,   24,   25,   26,   27,   28,   29,   30,   31,   32,   33,   34,   35,
  30     36,   37,   38,   39,   40,   41,   42,   43,   44,   45,   46,   47,   48,   49,   50,   51,
  31     52,   53,   54,   55,   56,   57,   58,   60,   62,   64,   66,   68,   70,   72,   74,   76,
  32     78,   80,   82,   84,   86,   88,   90,   92,   94,   96,   98,  100,  102,  104,  106,  108,
  33     110,  112,  114,  116,  119,  122,  125,  128,  131,  134,  137,  140,  143,  146,  149,  152,
  34     155,  158,  161,  164,  167,  170,  173,  177,  181,  185,  189,  193,  197,  201,  205,  209,
  35     213,  217,  221,  225,  229,  234,  239,  245,  249,  254,  259,  264,  269,  274,  279,  284,
  36 };
  37
  38
  39 int vp8_dc_quant(int QIndex, int Delta)
  40 {
  41     int retval;
  42
  43     QIndex = QIndex + Delta;
  44
  45     if (QIndex > 127)
  46         QIndex = 127;
  47     else if (QIndex < 0)
  48         QIndex = 0;
  49
  50     retval = dc_qlookup[ QIndex ];
  51     return retval;
  52 }
  53
  54 int vp8_dc2quant(int QIndex, int Delta)
  55 {
  56     int retval;
  57
  58     QIndex = QIndex + Delta;
  59
  60     if (QIndex > 127)
  61         QIndex = 127;
  62     else if (QIndex < 0)
  63         QIndex = 0;
  64
  65     retval = dc_qlookup[ QIndex ] * 2;
  66     return retval;
  67
  68 }
  69 int vp8_dc_uv_quant(int QIndex, int Delta)
  70 {
  71     int retval;
  72
  73     QIndex = QIndex + Delta;
  74
  75     if (QIndex > 127)
  76         QIndex = 127;
  77     else if (QIndex < 0)
  78         QIndex = 0;
  79
  80     retval = dc_qlookup[ QIndex ];
  81
  82     if (retval > 132)
  83         retval = 132;
  84
  85     return retval;
  86 }
  87
  88 int vp8_ac_yquant(int QIndex)
  89 {
  90     int retval;
  91
  92     if (QIndex > 127)
  93         QIndex = 127;
  94     else if (QIndex < 0)
  95         QIndex = 0;
  96
  97     retval = ac_qlookup[ QIndex ];
  98     return retval;
  99 }
 100
 101 int vp8_ac2quant(int QIndex, int Delta)
 102 {
 103     int retval;
 104
 105     QIndex = QIndex + Delta;
 106
 107     if (QIndex > 127)
 108         QIndex = 127;
 109     else if (QIndex < 0)
 110         QIndex = 0;
 111
 112     retval = (ac_qlookup[ QIndex ] * 155) / 100;
 113
 114     if (retval < 8)
 115         retval = 8;
 116
 117     return retval;
 118 }
 119 int vp8_ac_uv_quant(int QIndex, int Delta)
 120 {
 121     int retval;
 122
 123     QIndex = QIndex + Delta;
 124
 125     if (QIndex > 127)
 126         QIndex = 127;
 127     else if (QIndex < 0)
 128         QIndex = 0;
 129
 130     retval = ac_qlookup[ QIndex ];
 131     return retval;
 132 }