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
vp8_dc_quant(int QIndex,int Delta)37 int vp8_dc_quant(int QIndex, int Delta) {
38 int retval;
39
40 QIndex = QIndex + Delta;
41
42 if (QIndex > 127) {
43 QIndex = 127;
44 } else if (QIndex < 0) {
45 QIndex = 0;
46 }
47
48 retval = dc_qlookup[QIndex];
49 return retval;
50 }
51
vp8_dc2quant(int QIndex,int Delta)52 int vp8_dc2quant(int QIndex, int Delta) {
53 int retval;
54
55 QIndex = QIndex + Delta;
56
57 if (QIndex > 127) {
58 QIndex = 127;
59 } else if (QIndex < 0) {
60 QIndex = 0;
61 }
62
63 retval = dc_qlookup[QIndex] * 2;
64 return retval;
65 }
vp8_dc_uv_quant(int QIndex,int Delta)66 int vp8_dc_uv_quant(int QIndex, int Delta) {
67 int retval;
68
69 QIndex = QIndex + Delta;
70
71 if (QIndex > 127) {
72 QIndex = 127;
73 } else if (QIndex < 0) {
74 QIndex = 0;
75 }
76
77 retval = dc_qlookup[QIndex];
78
79 if (retval > 132) retval = 132;
80
81 return retval;
82 }
83
vp8_ac_yquant(int QIndex)84 int vp8_ac_yquant(int QIndex) {
85 int retval;
86
87 if (QIndex > 127) {
88 QIndex = 127;
89 } else if (QIndex < 0) {
90 QIndex = 0;
91 }
92
93 retval = ac_qlookup[QIndex];
94 return retval;
95 }
96
vp8_ac2quant(int QIndex,int Delta)97 int vp8_ac2quant(int QIndex, int Delta) {
98 int retval;
99
100 QIndex = QIndex + Delta;
101
102 if (QIndex > 127) {
103 QIndex = 127;
104 } else if (QIndex < 0) {
105 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 retval = (ac_qlookup[QIndex] * 101581) >> 16;
112
113 if (retval < 8) retval = 8;
114
115 return retval;
116 }
vp8_ac_uv_quant(int QIndex,int Delta)117 int vp8_ac_uv_quant(int QIndex, int Delta) {
118 int retval;
119
120 QIndex = QIndex + Delta;
121
122 if (QIndex > 127) {
123 QIndex = 127;
124 } else if (QIndex < 0) {
125 QIndex = 0;
126 }
127
128 retval = ac_qlookup[QIndex];
129 return retval;
130 }
131