Line data Source code
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 : #include "quant_common.h"
12 :
13 : static const int dc_qlookup[QINDEX_RANGE] = {
14 : 4, 5, 6, 7, 8, 9, 10, 10, 11, 12, 13, 14, 15, 16, 17,
15 : 17, 18, 19, 20, 20, 21, 21, 22, 22, 23, 23, 24, 25, 25, 26,
16 : 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 37, 38, 39, 40,
17 : 41, 42, 43, 44, 45, 46, 46, 47, 48, 49, 50, 51, 52, 53, 54,
18 : 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69,
19 : 70, 71, 72, 73, 74, 75, 76, 76, 77, 78, 79, 80, 81, 82, 83,
20 : 84, 85, 86, 87, 88, 89, 91, 93, 95, 96, 98, 100, 101, 102, 104,
21 : 106, 108, 110, 112, 114, 116, 118, 122, 124, 126, 128, 130, 132, 134, 136,
22 : 138, 140, 143, 145, 148, 151, 154, 157,
23 : };
24 :
25 : static const int ac_qlookup[QINDEX_RANGE] = {
26 : 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18,
27 : 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33,
28 : 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48,
29 : 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 60, 62, 64, 66, 68,
30 : 70, 72, 74, 76, 78, 80, 82, 84, 86, 88, 90, 92, 94, 96, 98,
31 : 100, 102, 104, 106, 108, 110, 112, 114, 116, 119, 122, 125, 128, 131, 134,
32 : 137, 140, 143, 146, 149, 152, 155, 158, 161, 164, 167, 170, 173, 177, 181,
33 : 185, 189, 193, 197, 201, 205, 209, 213, 217, 221, 225, 229, 234, 239, 245,
34 : 249, 254, 259, 264, 269, 274, 279, 284,
35 : };
36 :
37 0 : int vp8_dc_quant(int QIndex, int Delta) {
38 : int retval;
39 :
40 0 : QIndex = QIndex + Delta;
41 :
42 0 : if (QIndex > 127) {
43 0 : QIndex = 127;
44 0 : } else if (QIndex < 0) {
45 0 : QIndex = 0;
46 : }
47 :
48 0 : retval = dc_qlookup[QIndex];
49 0 : return retval;
50 : }
51 :
52 0 : int vp8_dc2quant(int QIndex, int Delta) {
53 : int retval;
54 :
55 0 : QIndex = QIndex + Delta;
56 :
57 0 : if (QIndex > 127) {
58 0 : QIndex = 127;
59 0 : } else if (QIndex < 0) {
60 0 : QIndex = 0;
61 : }
62 :
63 0 : retval = dc_qlookup[QIndex] * 2;
64 0 : return retval;
65 : }
66 0 : int vp8_dc_uv_quant(int QIndex, int Delta) {
67 : int retval;
68 :
69 0 : QIndex = QIndex + Delta;
70 :
71 0 : if (QIndex > 127) {
72 0 : QIndex = 127;
73 0 : } else if (QIndex < 0) {
74 0 : QIndex = 0;
75 : }
76 :
77 0 : retval = dc_qlookup[QIndex];
78 :
79 0 : if (retval > 132) retval = 132;
80 :
81 0 : return retval;
82 : }
83 :
84 0 : int vp8_ac_yquant(int QIndex) {
85 : int retval;
86 :
87 0 : if (QIndex > 127) {
88 0 : QIndex = 127;
89 0 : } else if (QIndex < 0) {
90 0 : QIndex = 0;
91 : }
92 :
93 0 : retval = ac_qlookup[QIndex];
94 0 : return retval;
95 : }
96 :
97 0 : int vp8_ac2quant(int QIndex, int Delta) {
98 : int retval;
99 :
100 0 : QIndex = QIndex + Delta;
101 :
102 0 : if (QIndex > 127) {
103 0 : QIndex = 127;
104 0 : } else if (QIndex < 0) {
105 0 : QIndex = 0;
106 : }
107 :
108 : /* For all x in [0..284], x*155/100 is bitwise equal to (x*101581) >> 16.
109 : * The smallest precision for that is '(x*6349) >> 12' but 16 is a good
110 : * word size. */
111 0 : retval = (ac_qlookup[QIndex] * 101581) >> 16;
112 :
113 0 : if (retval < 8) retval = 8;
114 :
115 0 : return retval;
116 : }
117 0 : int vp8_ac_uv_quant(int QIndex, int Delta) {
118 : int retval;
119 :
120 0 : QIndex = QIndex + Delta;
121 :
122 0 : if (QIndex > 127) {
123 0 : QIndex = 127;
124 0 : } else if (QIndex < 0) {
125 0 : QIndex = 0;
126 : }
127 :
128 0 : retval = ac_qlookup[QIndex];
129 0 : return retval;
130 : }
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