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| 1 : | Isibaar | 1.1 | /************************************************************************** |
| 2 : | * | ||
| 3 : | * XVID MPEG-4 VIDEO CODEC | ||
| 4 : | * mpeg-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 : | * 26.01.2002 fixed quant4_intra dcscalar signed/unsigned error | ||
| 36 : | * 20.01.2002 increased accuracy of >> divide | ||
| 37 : | * 26.12.2001 divide-by-multiplication optimization | ||
| 38 : | * 22.12.2001 [-127,127] clamping removed; minor tweaks | ||
| 39 : | * 19.11.2001 inital version <pross@cs.rmit.edu.au> | ||
| 40 : | * | ||
| 41 : | *************************************************************************/ | ||
| 42 : | |||
| 43 : | |||
| 44 : | #include "quant_mpeg4.h" | ||
| 45 : | |||
| 46 : | |||
| 47 : | |||
| 48 : | // function pointers | ||
| 49 : | quant_intraFuncPtr quant4_intra; | ||
| 50 : | quant_intraFuncPtr dequant4_intra; | ||
| 51 : | dequant_interFuncPtr dequant4_inter; | ||
| 52 : | quant_interFuncPtr quant4_inter; | ||
| 53 : | |||
| 54 : | |||
| 55 : | #define DIV_DIV(A,B) ( (A) > 0 ? ((A)+((B)>>1))/(B) : ((A)-((B)>>1))/(B) ) | ||
| 56 : | #define SIGN(A) ((A)>0?1:-1) | ||
| 57 : | #define VM18P 3 | ||
| 58 : | #define VM18Q 4 | ||
| 59 : | |||
| 60 : | |||
| 61 : | // divide-by-multiply table | ||
| 62 : | // need 17 bit shift (16 causes slight errors when q > 19) | ||
| 63 : | |||
| 64 : | #define SCALEBITS 17 | ||
| 65 : | #define FIX(X) ((1UL << SCALEBITS) / (X) + 1) | ||
| 66 : | |||
| 67 : | static const uint32_t multipliers[32] = | ||
| 68 : | { | ||
| 69 : | 0, FIX(2), FIX(4), FIX(6), | ||
| 70 : | FIX(8), FIX(10), FIX(12), FIX(14), | ||
| 71 : | FIX(16), FIX(18), FIX(20), FIX(22), | ||
| 72 : | FIX(24), FIX(26), FIX(28), FIX(30), | ||
| 73 : | FIX(32), FIX(34), FIX(36), FIX(38), | ||
| 74 : | FIX(40), FIX(42), FIX(44), FIX(46), | ||
| 75 : | FIX(48), FIX(50), FIX(52), FIX(54), | ||
| 76 : | FIX(56), FIX(58), FIX(60), FIX(62) | ||
| 77 : | }; | ||
| 78 : | |||
| 79 : | |||
| 80 : | static const int16_t default_intra_matrix[64] = { | ||
| 81 : | 8,17,18,19,21,23,25,27, | ||
| 82 : | 17,18,19,21,23,25,27,28, | ||
| 83 : | 20,21,22,23,24,26,28,30, | ||
| 84 : | 21,22,23,24,26,28,30,32, | ||
| 85 : | 22,23,24,26,28,30,32,35, | ||
| 86 : | 23,24,26,28,30,32,35,38, | ||
| 87 : | 25,26,28,30,32,35,38,41, | ||
| 88 : | 27,28,30,32,35,38,41,45 | ||
| 89 : | }; | ||
| 90 : | |||
| 91 : | static const int16_t default_inter_matrix[64] = { | ||
| 92 : | 16,17,18,19,20,21,22,23, | ||
| 93 : | 17,18,19,20,21,22,23,24, | ||
| 94 : | 18,19,20,21,22,23,24,25, | ||
| 95 : | 19,20,21,22,23,24,26,27, | ||
| 96 : | 20,21,22,23,25,26,27,28, | ||
| 97 : | 21,22,23,24,26,27,28,30, | ||
| 98 : | 22,23,24,26,27,28,30,31, | ||
| 99 : | 23,24,25,27,28,30,31,33 | ||
| 100 : | }; | ||
| 101 : | |||
| 102 : | |||
| 103 : | /* quantize intra-block | ||
| 104 : | |||
| 105 : | // const int32_t quantd = DIV_DIV(VM18P*quant, VM18Q); | ||
| 106 : | // | ||
| 107 : | // level = DIV_DIV(16 * data[i], default_intra_matrix[i]); | ||
| 108 : | // coeff[i] = (level + quantd) / quant2; | ||
| 109 : | */ | ||
| 110 : | |||
| 111 : | void quant4_intra_c(int16_t * coeff, const int16_t * data, const uint32_t quant, const uint32_t dcscalar) | ||
| 112 : | { | ||
| 113 : | const uint32_t quantd = ((VM18P*quant) + (VM18Q/2)) / VM18Q; | ||
| 114 : | const uint32_t mult = multipliers[quant]; | ||
| 115 : | uint32_t i; | ||
| 116 : | |||
| 117 : | coeff[0] = DIV_DIV(data[0], (int32_t)dcscalar); | ||
| 118 : | |||
| 119 : | for (i = 1; i < 64; i++) | ||
| 120 : | { | ||
| 121 : | if (data[i] < 0) | ||
| 122 : | { | ||
| 123 : | uint32_t level = -data[i]; | ||
| 124 : | level = ((level<<4) + (default_intra_matrix[i]>>1)) / default_intra_matrix[i]; | ||
| 125 : | level = ((level + quantd) * mult) >> 17; | ||
| 126 : | coeff[i] = -(int16_t)level; | ||
| 127 : | } | ||
| 128 : | else if (data[i] > 0) | ||
| 129 : | { | ||
| 130 : | uint32_t level = data[i]; | ||
| 131 : | level = ((level<<4) + (default_intra_matrix[i]>>1)) / default_intra_matrix[i]; | ||
| 132 : | level = ((level + quantd) * mult) >> 17; | ||
| 133 : | coeff[i] = level; | ||
| 134 : | } | ||
| 135 : | else | ||
| 136 : | { | ||
| 137 : | coeff[i] = 0; | ||
| 138 : | } | ||
| 139 : | } | ||
| 140 : | } | ||
| 141 : | |||
| 142 : | |||
| 143 : | |||
| 144 : | /* dequantize intra-block & clamp to [-2048,2047] | ||
| 145 : | // data[i] = (coeff[i] * default_intra_matrix[i] * quant2) >> 4; | ||
| 146 : | */ | ||
| 147 : | |||
| 148 : | void dequant4_intra_c(int16_t *data, const int16_t *coeff, const uint32_t quant, const uint32_t dcscalar) | ||
| 149 : | { | ||
| 150 : | uint32_t i; | ||
| 151 : | |||
| 152 : | data[0] = coeff[0] * dcscalar; | ||
| 153 : | if (data[0] < -2048) | ||
| 154 : | { | ||
| 155 : | data[0] = -2048; | ||
| 156 : | } | ||
| 157 : | else if (data[0] > 2047) | ||
| 158 : | { | ||
| 159 : | data[0] = 2047; | ||
| 160 : | } | ||
| 161 : | |||
| 162 : | for (i = 1; i < 64; i++) | ||
| 163 : | { | ||
| 164 : | if (coeff[i] == 0) | ||
| 165 : | { | ||
| 166 : | data[i] = 0; | ||
| 167 : | } | ||
| 168 : | else if (coeff[i] < 0) | ||
| 169 : | { | ||
| 170 : | uint32_t level = -coeff[i]; | ||
| 171 : | level = (level * default_intra_matrix[i] * quant) >> 3; | ||
| 172 : | data[i] = (level <= 2048 ? -(int16_t)level : -2048); | ||
| 173 : | } | ||
| 174 : | else // if (coeff[i] > 0) | ||
| 175 : | { | ||
| 176 : | uint32_t level = coeff[i]; | ||
| 177 : | level = (level * default_intra_matrix[i] * quant) >> 3; | ||
| 178 : | data[i] = (level <= 2047 ? level : 2047); | ||
| 179 : | } | ||
| 180 : | } | ||
| 181 : | } | ||
| 182 : | |||
| 183 : | |||
| 184 : | |||
| 185 : | /* quantize inter-block | ||
| 186 : | |||
| 187 : | // level = DIV_DIV(16 * data[i], default_intra_matrix[i]); | ||
| 188 : | // coeff[i] = (level + quantd) / quant2; | ||
| 189 : | // sum += abs(level); | ||
| 190 : | */ | ||
| 191 : | |||
| 192 : | uint32_t quant4_inter_c(int16_t * coeff, const int16_t * data, const uint32_t quant) | ||
| 193 : | { | ||
| 194 : | const uint32_t mult = multipliers[quant]; | ||
| 195 : | uint32_t sum = 0; | ||
| 196 : | uint32_t i; | ||
| 197 : | |||
| 198 : | for (i = 0; i < 64; i++) | ||
| 199 : | { | ||
| 200 : | if (data[i] < 0) | ||
| 201 : | { | ||
| 202 : | uint32_t level = -data[i]; | ||
| 203 : | level = ((level<<4) + (default_inter_matrix[i]>>1)) / default_inter_matrix[i]; | ||
| 204 : | level = (level * mult) >> 17; | ||
| 205 : | sum += level; | ||
| 206 : | coeff[i] = -(int16_t)level; | ||
| 207 : | } | ||
| 208 : | else if (data[i] > 0) | ||
| 209 : | { | ||
| 210 : | uint32_t level = data[i]; | ||
| 211 : | level = ((level<<4) + (default_inter_matrix[i]>>1)) / default_inter_matrix[i]; | ||
| 212 : | level = (level * mult) >> 17; | ||
| 213 : | sum += level; | ||
| 214 : | coeff[i] = level; | ||
| 215 : | } | ||
| 216 : | else | ||
| 217 : | { | ||
| 218 : | coeff[i] = 0; | ||
| 219 : | } | ||
| 220 : | } | ||
| 221 : | return sum; | ||
| 222 : | } | ||
| 223 : | |||
| 224 : | |||
| 225 : | |||
| 226 : | /* dequantize inter-block & clamp to [-2048,2047] | ||
| 227 : | data = ((2 * coeff + SIGN(coeff)) * inter_matrix[i] * quant) / 16 | ||
| 228 : | */ | ||
| 229 : | |||
| 230 : | void dequant4_inter_c(int16_t *data, const int16_t *coeff, const uint32_t quant) | ||
| 231 : | { | ||
| 232 : | uint32_t sum = 0; | ||
| 233 : | uint32_t i; | ||
| 234 : | |||
| 235 : | for (i = 0; i < 64; i++) | ||
| 236 : | { | ||
| 237 : | if (coeff[i] == 0) | ||
| 238 : | { | ||
| 239 : | data[i] = 0; | ||
| 240 : | } | ||
| 241 : | else if (coeff[i] < 0) | ||
| 242 : | { | ||
| 243 : | int32_t level = -coeff[i]; | ||
| 244 : | level = ((2 * level + 1) * default_inter_matrix[i] * quant) >> 4; | ||
| 245 : | data[i] = (level <= 2048 ? -level : -2048); | ||
| 246 : | } | ||
| 247 : | else // if (coeff[i] > 0) | ||
| 248 : | { | ||
| 249 : | uint32_t level = coeff[i]; | ||
| 250 : | level = ((2 * level + 1) * default_inter_matrix[i] * quant) >> 4; | ||
| 251 : | data[i] = (level <= 2047 ? level : 2047); | ||
| 252 : | } | ||
| 253 : | |||
| 254 : | sum ^= data[i]; | ||
| 255 : | } | ||
| 256 : | |||
| 257 : | // mismatch control | ||
| 258 : | |||
| 259 : | if ((sum & 1) == 0) | ||
| 260 : | { | ||
| 261 : | data[63] ^= 1; | ||
| 262 : | } | ||
| 263 : | } |
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