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| 1 : | Isibaar | 3 | /************************************************************************** |
| 2 : | * | ||
| 3 : | * XVID MPEG-4 VIDEO CODEC | ||
| 4 : | * quantization/dequantization | ||
| 5 : | * | ||
| 6 : | * This program is an implementation of a part of one or more MPEG-4 | ||
| 7 : | * Video tools as specified in ISO/IEC 14496-2 standard. Those intending | ||
| 8 : | * to use this software module in hardware or software products are | ||
| 9 : | * advised that its use may infringe existing patents or copyrights, and | ||
| 10 : | * any such use would be at such party's own risk. The original | ||
| 11 : | * developer of this software module and his/her company, and subsequent | ||
| 12 : | * editors and their companies, will have no liability for use of this | ||
| 13 : | * software or modifications or derivatives thereof. | ||
| 14 : | * | ||
| 15 : | * This program is free software; you can redistribute it and/or modify | ||
| 16 : | * it under the terms of the GNU General Public License as published by | ||
| 17 : | * the Free Software Foundation; either version 2 of the License, or | ||
| 18 : | * (at your option) any later version. | ||
| 19 : | * | ||
| 20 : | * This program is distributed in the hope that it will be useful, | ||
| 21 : | * but WITHOUT ANY WARRANTY; without even the implied warranty of | ||
| 22 : | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | ||
| 23 : | * GNU General Public License for more details. | ||
| 24 : | * | ||
| 25 : | * You should have received a copy of the GNU General Public License | ||
| 26 : | * along with this program; if not, write to the Free Software | ||
| 27 : | * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. | ||
| 28 : | * | ||
| 29 : | *************************************************************************/ | ||
| 30 : | |||
| 31 : | /************************************************************************** | ||
| 32 : | * | ||
| 33 : | * History: | ||
| 34 : | * | ||
| 35 : | * 26.12.2001 dequant_inter bug fix | ||
| 36 : | * 22.12.2001 clamp dequant output to [-2048,2047] | ||
| 37 : | * 19.11.2001 quant_inter now returns sum of abs. coefficient values | ||
| 38 : | * 02.11.2001 added const to function args <pross@cs.rmit.edu.au> | ||
| 39 : | * 28.10.2001 total rewrite <pross@cs.rmit.edu.au> | ||
| 40 : | * | ||
| 41 : | *************************************************************************/ | ||
| 42 : | |||
| 43 : | #include "quant_h263.h" | ||
| 44 : | |||
| 45 : | /* mutliply+shift division table | ||
| 46 : | */ | ||
| 47 : | |||
| 48 : | #define SCALEBITS 16 | ||
| 49 : | #define FIX(X) ((1L << SCALEBITS) / (X) + 1) | ||
| 50 : | |||
| 51 : | static const uint32_t multipliers[32] = | ||
| 52 : | { | ||
| 53 : | 0, FIX(2), FIX(4), FIX(6), | ||
| 54 : | FIX(8), FIX(10), FIX(12), FIX(14), | ||
| 55 : | FIX(16), FIX(18), FIX(20), FIX(22), | ||
| 56 : | FIX(24), FIX(26), FIX(28), FIX(30), | ||
| 57 : | FIX(32), FIX(34), FIX(36), FIX(38), | ||
| 58 : | FIX(40), FIX(42), FIX(44), FIX(46), | ||
| 59 : | FIX(48), FIX(50), FIX(52), FIX(54), | ||
| 60 : | FIX(56), FIX(58), FIX(60), FIX(62) | ||
| 61 : | }; | ||
| 62 : | |||
| 63 : | |||
| 64 : | |||
| 65 : | #define DIV_DIV(a, b) ((a)>0) ? ((a)+((b)>>1))/(b) : ((a)-((b)>>1))/(b) | ||
| 66 : | |||
| 67 : | // function pointers | ||
| 68 : | quanth263_intraFuncPtr quant_intra; | ||
| 69 : | quanth263_intraFuncPtr dequant_intra; | ||
| 70 : | |||
| 71 : | quanth263_interFuncPtr quant_inter; | ||
| 72 : | dequanth263_interFuncPtr dequant_inter; | ||
| 73 : | |||
| 74 : | |||
| 75 : | |||
| 76 : | /* quantize intra-block | ||
| 77 : | */ | ||
| 78 : | |||
| 79 : | |||
| 80 : | void quant_intra_c(int16_t * coeff, const int16_t * data, const uint32_t quant, const uint32_t dcscalar) | ||
| 81 : | { | ||
| 82 : | const uint32_t mult = multipliers[quant]; | ||
| 83 : | const uint16_t quant_m_2 = quant << 1; | ||
| 84 : | uint32_t i; | ||
| 85 : | |||
| 86 : | coeff[0] = DIV_DIV(data[0], (int32_t)dcscalar); | ||
| 87 : | |||
| 88 : | for (i = 1; i < 64; i++) { | ||
| 89 : | int16_t acLevel = data[i]; | ||
| 90 : | |||
| 91 : | if (acLevel < 0) { | ||
| 92 : | acLevel = -acLevel; | ||
| 93 : | if (acLevel < quant_m_2) { | ||
| 94 : | coeff[i] = 0; | ||
| 95 : | continue; | ||
| 96 : | } | ||
| 97 : | acLevel = (acLevel * mult) >> SCALEBITS; | ||
| 98 : | coeff[i] = -acLevel; | ||
| 99 : | } else { | ||
| 100 : | if (acLevel < quant_m_2) { | ||
| 101 : | coeff[i] = 0; | ||
| 102 : | continue; | ||
| 103 : | } | ||
| 104 : | acLevel = (acLevel * mult) >> SCALEBITS; | ||
| 105 : | coeff[i] = acLevel; | ||
| 106 : | } | ||
| 107 : | } | ||
| 108 : | } | ||
| 109 : | |||
| 110 : | |||
| 111 : | /* quantize inter-block | ||
| 112 : | */ | ||
| 113 : | |||
| 114 : | uint32_t quant_inter_c(int16_t *coeff, const int16_t *data, const uint32_t quant) | ||
| 115 : | { | ||
| 116 : | const uint32_t mult = multipliers[quant]; | ||
| 117 : | const uint16_t quant_m_2 = quant << 1; | ||
| 118 : | const uint16_t quant_d_2 = quant >> 1; | ||
| 119 : | int sum = 0; | ||
| 120 : | uint32_t i; | ||
| 121 : | |||
| 122 : | for (i = 0; i < 64; i++) { | ||
| 123 : | int16_t acLevel = data[i]; | ||
| 124 : | |||
| 125 : | if (acLevel < 0) { | ||
| 126 : | acLevel = (-acLevel) - quant_d_2; | ||
| 127 : | if (acLevel < quant_m_2) { | ||
| 128 : | coeff[i] = 0; | ||
| 129 : | continue; | ||
| 130 : | } | ||
| 131 : | |||
| 132 : | acLevel = (acLevel * mult) >> SCALEBITS; | ||
| 133 : | sum += acLevel; // sum += |acLevel| | ||
| 134 : | coeff[i] = -acLevel; | ||
| 135 : | } else { | ||
| 136 : | acLevel -= quant_d_2; | ||
| 137 : | if (acLevel < quant_m_2) { | ||
| 138 : | coeff[i] = 0; | ||
| 139 : | continue; | ||
| 140 : | } | ||
| 141 : | acLevel = (acLevel * mult) >> SCALEBITS; | ||
| 142 : | sum += acLevel; | ||
| 143 : | coeff[i] = acLevel; | ||
| 144 : | } | ||
| 145 : | } | ||
| 146 : | |||
| 147 : | return sum; | ||
| 148 : | } | ||
| 149 : | |||
| 150 : | |||
| 151 : | /* dequantize intra-block & clamp to [-2048,2047] | ||
| 152 : | */ | ||
| 153 : | |||
| 154 : | void dequant_intra_c(int16_t *data, const int16_t *coeff, const uint32_t quant, const uint32_t dcscalar) | ||
| 155 : | { | ||
| 156 : | const int32_t quant_m_2 = quant << 1; | ||
| 157 : | const int32_t quant_add = (quant & 1 ? quant : quant - 1); | ||
| 158 : | uint32_t i; | ||
| 159 : | |||
| 160 : | data[0] = coeff[0] * dcscalar; | ||
| 161 : | if (data[0] < -2048) | ||
| 162 : | { | ||
| 163 : | data[0] = -2048; | ||
| 164 : | } | ||
| 165 : | else if (data[0] > 2047) | ||
| 166 : | { | ||
| 167 : | data[0] = 2047; | ||
| 168 : | } | ||
| 169 : | |||
| 170 : | |||
| 171 : | for (i = 1; i < 64; i++) { | ||
| 172 : | int32_t acLevel = coeff[i]; | ||
| 173 : | if (acLevel == 0) | ||
| 174 : | { | ||
| 175 : | data[i] = 0; | ||
| 176 : | } | ||
| 177 : | else if (acLevel < 0) | ||
| 178 : | { | ||
| 179 : | acLevel = quant_m_2 * -acLevel + quant_add; | ||
| 180 : | data[i] = (acLevel <= 2048 ? -acLevel : -2048); | ||
| 181 : | } | ||
| 182 : | else // if (acLevel > 0) { | ||
| 183 : | { | ||
| 184 : | acLevel = quant_m_2 * acLevel + quant_add; | ||
| 185 : | data[i] = (acLevel <= 2047 ? acLevel : 2047); | ||
| 186 : | } | ||
| 187 : | } | ||
| 188 : | } | ||
| 189 : | |||
| 190 : | |||
| 191 : | |||
| 192 : | /* dequantize inter-block & clamp to [-2048,2047] | ||
| 193 : | */ | ||
| 194 : | |||
| 195 : | void dequant_inter_c(int16_t *data, const int16_t *coeff, const uint32_t quant) | ||
| 196 : | { | ||
| 197 : | const uint16_t quant_m_2 = quant << 1; | ||
| 198 : | const uint16_t quant_add = (quant & 1 ? quant : quant - 1); | ||
| 199 : | uint32_t i; | ||
| 200 : | |||
| 201 : | for (i = 0; i < 64; i++) { | ||
| 202 : | int16_t acLevel = coeff[i]; | ||
| 203 : | |||
| 204 : | if (acLevel == 0) | ||
| 205 : | { | ||
| 206 : | data[i] = 0; | ||
| 207 : | } | ||
| 208 : | else if (acLevel < 0) | ||
| 209 : | { | ||
| 210 : | acLevel = acLevel * quant_m_2 - quant_add; | ||
| 211 : | data[i] = (acLevel >= -2048 ? acLevel : -2048); | ||
| 212 : | } | ||
| 213 : | else // if (acLevel > 0) | ||
| 214 : | { | ||
| 215 : | acLevel = acLevel * quant_m_2 + quant_add; | ||
| 216 : | data[i] = (acLevel <= 2047 ? acLevel : 2047); | ||
| 217 : | } | ||
| 218 : | } | ||
| 219 : | } |
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