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 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 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 } 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 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 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 } 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
