media/libvpx/vp8/common/quant_common.c@ac0c01689b40
media/libvpx/vp8/common/quant_common.c
Thu, 15 Jan 2015 15:59:08 +0100
- author
- Michael Schloh von Bennewitz <michael@schloh.com>
- date
- Thu, 15 Jan 2015 15:59:08 +0100
- branch
- TOR_BUG_9701
- changeset 10
- ac0c01689b40
- permissions
- -rw-r--r--
Implement a real Private Browsing Mode condition by changing the API/ABI;
This solves Tor bug #9701, complying with disk avoidance documented in
https://www.torproject.org/projects/torbrowser/design/#disk-avoidance.
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 */
12 #include "quant_common.h"
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 };
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 };
39 int vp8_dc_quant(int QIndex, int Delta)
40 {
41 int retval;
43 QIndex = QIndex + Delta;
45 if (QIndex > 127)
46 QIndex = 127;
47 else if (QIndex < 0)
48 QIndex = 0;
50 retval = dc_qlookup[ QIndex ];
51 return retval;
52 }
54 int vp8_dc2quant(int QIndex, int Delta)
55 {
56 int retval;
58 QIndex = QIndex + Delta;
60 if (QIndex > 127)
61 QIndex = 127;
62 else if (QIndex < 0)
63 QIndex = 0;
65 retval = dc_qlookup[ QIndex ] * 2;
66 return retval;
68 }
69 int vp8_dc_uv_quant(int QIndex, int Delta)
70 {
71 int retval;
73 QIndex = QIndex + Delta;
75 if (QIndex > 127)
76 QIndex = 127;
77 else if (QIndex < 0)
78 QIndex = 0;
80 retval = dc_qlookup[ QIndex ];
82 if (retval > 132)
83 retval = 132;
85 return retval;
86 }
88 int vp8_ac_yquant(int QIndex)
89 {
90 int retval;
92 if (QIndex > 127)
93 QIndex = 127;
94 else if (QIndex < 0)
95 QIndex = 0;
97 retval = ac_qlookup[ QIndex ];
98 return retval;
99 }
101 int vp8_ac2quant(int QIndex, int Delta)
102 {
103 int retval;
105 QIndex = QIndex + Delta;
107 if (QIndex > 127)
108 QIndex = 127;
109 else if (QIndex < 0)
110 QIndex = 0;
112 /* For all x in [0..284], x*155/100 is bitwise equal to (x*101581) >> 16.
113 * The smallest precision for that is '(x*6349) >> 12' but 16 is a good
114 * word size. */
115 retval = (ac_qlookup[ QIndex ] * 101581) >> 16;
117 if (retval < 8)
118 retval = 8;
120 return retval;
121 }
122 int vp8_ac_uv_quant(int QIndex, int Delta)
123 {
124 int retval;
126 QIndex = QIndex + Delta;
128 if (QIndex > 127)
129 QIndex = 127;
130 else if (QIndex < 0)
131 QIndex = 0;
133 retval = ac_qlookup[ QIndex ];
134 return retval;
135 }
