| Line | Branch | Exec | Source |
|---|---|---|---|
| 1 | /* | ||
| 2 | * This file is part of the Independent JPEG Group's software. | ||
| 3 | * | ||
| 4 | * The authors make NO WARRANTY or representation, either express or implied, | ||
| 5 | * with respect to this software, its quality, accuracy, merchantability, or | ||
| 6 | * fitness for a particular purpose. This software is provided "AS IS", and | ||
| 7 | * you, its user, assume the entire risk as to its quality and accuracy. | ||
| 8 | * | ||
| 9 | * This software is copyright (C) 1994-1996, Thomas G. Lane. | ||
| 10 | * All Rights Reserved except as specified below. | ||
| 11 | * | ||
| 12 | * Permission is hereby granted to use, copy, modify, and distribute this | ||
| 13 | * software (or portions thereof) for any purpose, without fee, subject to | ||
| 14 | * these conditions: | ||
| 15 | * (1) If any part of the source code for this software is distributed, then | ||
| 16 | * this README file must be included, with this copyright and no-warranty | ||
| 17 | * notice unaltered; and any additions, deletions, or changes to the original | ||
| 18 | * files must be clearly indicated in accompanying documentation. | ||
| 19 | * (2) If only executable code is distributed, then the accompanying | ||
| 20 | * documentation must state that "this software is based in part on the work | ||
| 21 | * of the Independent JPEG Group". | ||
| 22 | * (3) Permission for use of this software is granted only if the user accepts | ||
| 23 | * full responsibility for any undesirable consequences; the authors accept | ||
| 24 | * NO LIABILITY for damages of any kind. | ||
| 25 | * | ||
| 26 | * These conditions apply to any software derived from or based on the IJG | ||
| 27 | * code, not just to the unmodified library. If you use our work, you ought | ||
| 28 | * to acknowledge us. | ||
| 29 | * | ||
| 30 | * Permission is NOT granted for the use of any IJG author's name or company | ||
| 31 | * name in advertising or publicity relating to this software or products | ||
| 32 | * derived from it. This software may be referred to only as "the Independent | ||
| 33 | * JPEG Group's software". | ||
| 34 | * | ||
| 35 | * We specifically permit and encourage the use of this software as the basis | ||
| 36 | * of commercial products, provided that all warranty or liability claims are | ||
| 37 | * assumed by the product vendor. | ||
| 38 | * | ||
| 39 | * This file contains a fast, not so accurate integer implementation of the | ||
| 40 | * forward DCT (Discrete Cosine Transform). | ||
| 41 | * | ||
| 42 | * A 2-D DCT can be done by 1-D DCT on each row followed by 1-D DCT | ||
| 43 | * on each column. Direct algorithms are also available, but they are | ||
| 44 | * much more complex and seem not to be any faster when reduced to code. | ||
| 45 | * | ||
| 46 | * This implementation is based on Arai, Agui, and Nakajima's algorithm for | ||
| 47 | * scaled DCT. Their original paper (Trans. IEICE E-71(11):1095) is in | ||
| 48 | * Japanese, but the algorithm is described in the Pennebaker & Mitchell | ||
| 49 | * JPEG textbook (see REFERENCES section in file README). The following code | ||
| 50 | * is based directly on figure 4-8 in P&M. | ||
| 51 | * While an 8-point DCT cannot be done in less than 11 multiplies, it is | ||
| 52 | * possible to arrange the computation so that many of the multiplies are | ||
| 53 | * simple scalings of the final outputs. These multiplies can then be | ||
| 54 | * folded into the multiplications or divisions by the JPEG quantization | ||
| 55 | * table entries. The AA&N method leaves only 5 multiplies and 29 adds | ||
| 56 | * to be done in the DCT itself. | ||
| 57 | * The primary disadvantage of this method is that with fixed-point math, | ||
| 58 | * accuracy is lost due to imprecise representation of the scaled | ||
| 59 | * quantization values. The smaller the quantization table entry, the less | ||
| 60 | * precise the scaled value, so this implementation does worse with high- | ||
| 61 | * quality-setting files than with low-quality ones. | ||
| 62 | */ | ||
| 63 | |||
| 64 | /** | ||
| 65 | * @file | ||
| 66 | * Independent JPEG Group's fast AAN dct. | ||
| 67 | */ | ||
| 68 | |||
| 69 | #include <stdint.h> | ||
| 70 | #include "libavutil/attributes.h" | ||
| 71 | #include "fdctdsp.h" | ||
| 72 | |||
| 73 | #define DCTSIZE 8 | ||
| 74 | #define GLOBAL(x) x | ||
| 75 | #define RIGHT_SHIFT(x, n) ((x) >> (n)) | ||
| 76 | |||
| 77 | /* | ||
| 78 | * This module is specialized to the case DCTSIZE = 8. | ||
| 79 | */ | ||
| 80 | |||
| 81 | #if DCTSIZE != 8 | ||
| 82 | Sorry, this code only copes with 8x8 DCTs. /* deliberate syntax err */ | ||
| 83 | #endif | ||
| 84 | |||
| 85 | |||
| 86 | /* Scaling decisions are generally the same as in the LL&M algorithm; | ||
| 87 | * see jfdctint.c for more details. However, we choose to descale | ||
| 88 | * (right shift) multiplication products as soon as they are formed, | ||
| 89 | * rather than carrying additional fractional bits into subsequent additions. | ||
| 90 | * This compromises accuracy slightly, but it lets us save a few shifts. | ||
| 91 | * More importantly, 16-bit arithmetic is then adequate (for 8-bit samples) | ||
| 92 | * everywhere except in the multiplications proper; this saves a good deal | ||
| 93 | * of work on 16-bit-int machines. | ||
| 94 | * | ||
| 95 | * Again to save a few shifts, the intermediate results between pass 1 and | ||
| 96 | * pass 2 are not upscaled, but are represented only to integral precision. | ||
| 97 | * | ||
| 98 | * A final compromise is to represent the multiplicative constants to only | ||
| 99 | * 8 fractional bits, rather than 13. This saves some shifting work on some | ||
| 100 | * machines, and may also reduce the cost of multiplication (since there | ||
| 101 | * are fewer one-bits in the constants). | ||
| 102 | */ | ||
| 103 | |||
| 104 | #define CONST_BITS 8 | ||
| 105 | |||
| 106 | |||
| 107 | /* Some C compilers fail to reduce "FIX(constant)" at compile time, thus | ||
| 108 | * causing a lot of useless floating-point operations at run time. | ||
| 109 | * To get around this we use the following pre-calculated constants. | ||
| 110 | * If you change CONST_BITS you may want to add appropriate values. | ||
| 111 | * (With a reasonable C compiler, you can just rely on the FIX() macro...) | ||
| 112 | */ | ||
| 113 | |||
| 114 | #if CONST_BITS == 8 | ||
| 115 | #define FIX_0_382683433 ((int32_t) 98) /* FIX(0.382683433) */ | ||
| 116 | #define FIX_0_541196100 ((int32_t) 139) /* FIX(0.541196100) */ | ||
| 117 | #define FIX_0_707106781 ((int32_t) 181) /* FIX(0.707106781) */ | ||
| 118 | #define FIX_1_306562965 ((int32_t) 334) /* FIX(1.306562965) */ | ||
| 119 | #else | ||
| 120 | #define FIX_0_382683433 FIX(0.382683433) | ||
| 121 | #define FIX_0_541196100 FIX(0.541196100) | ||
| 122 | #define FIX_0_707106781 FIX(0.707106781) | ||
| 123 | #define FIX_1_306562965 FIX(1.306562965) | ||
| 124 | #endif | ||
| 125 | |||
| 126 | |||
| 127 | /* We can gain a little more speed, with a further compromise in accuracy, | ||
| 128 | * by omitting the addition in a descaling shift. This yields an incorrectly | ||
| 129 | * rounded result half the time... | ||
| 130 | */ | ||
| 131 | |||
| 132 | #ifndef USE_ACCURATE_ROUNDING | ||
| 133 | #undef DESCALE | ||
| 134 | #define DESCALE(x,n) RIGHT_SHIFT(x, n) | ||
| 135 | #endif | ||
| 136 | |||
| 137 | |||
| 138 | /* Multiply a int16_t variable by an int32_t constant, and immediately | ||
| 139 | * descale to yield a int16_t result. | ||
| 140 | */ | ||
| 141 | |||
| 142 | #define MULTIPLY(var,const) ((int16_t) DESCALE((var) * (const), CONST_BITS)) | ||
| 143 | |||
| 144 | 103063916 | static av_always_inline void row_fdct(int16_t * data){ | |
| 145 | int tmp0, tmp1, tmp2, tmp3, tmp4, tmp5, tmp6, tmp7; | ||
| 146 | int tmp10, tmp11, tmp12, tmp13; | ||
| 147 | int z1, z2, z3, z4, z5, z11, z13; | ||
| 148 | int16_t *dataptr; | ||
| 149 | int ctr; | ||
| 150 | |||
| 151 | /* Pass 1: process rows. */ | ||
| 152 | |||
| 153 | 103063916 | dataptr = data; | |
| 154 |
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927575244 | for (ctr = DCTSIZE-1; ctr >= 0; ctr--) { |
| 155 | 824511328 | tmp0 = dataptr[0] + dataptr[7]; | |
| 156 | 824511328 | tmp7 = dataptr[0] - dataptr[7]; | |
| 157 | 824511328 | tmp1 = dataptr[1] + dataptr[6]; | |
| 158 | 824511328 | tmp6 = dataptr[1] - dataptr[6]; | |
| 159 | 824511328 | tmp2 = dataptr[2] + dataptr[5]; | |
| 160 | 824511328 | tmp5 = dataptr[2] - dataptr[5]; | |
| 161 | 824511328 | tmp3 = dataptr[3] + dataptr[4]; | |
| 162 | 824511328 | tmp4 = dataptr[3] - dataptr[4]; | |
| 163 | |||
| 164 | /* Even part */ | ||
| 165 | |||
| 166 | 824511328 | tmp10 = tmp0 + tmp3; /* phase 2 */ | |
| 167 | 824511328 | tmp13 = tmp0 - tmp3; | |
| 168 | 824511328 | tmp11 = tmp1 + tmp2; | |
| 169 | 824511328 | tmp12 = tmp1 - tmp2; | |
| 170 | |||
| 171 | 824511328 | dataptr[0] = tmp10 + tmp11; /* phase 3 */ | |
| 172 | 824511328 | dataptr[4] = tmp10 - tmp11; | |
| 173 | |||
| 174 | 824511328 | z1 = MULTIPLY(tmp12 + tmp13, FIX_0_707106781); /* c4 */ | |
| 175 | 824511328 | dataptr[2] = tmp13 + z1; /* phase 5 */ | |
| 176 | 824511328 | dataptr[6] = tmp13 - z1; | |
| 177 | |||
| 178 | /* Odd part */ | ||
| 179 | |||
| 180 | 824511328 | tmp10 = tmp4 + tmp5; /* phase 2 */ | |
| 181 | 824511328 | tmp11 = tmp5 + tmp6; | |
| 182 | 824511328 | tmp12 = tmp6 + tmp7; | |
| 183 | |||
| 184 | /* The rotator is modified from fig 4-8 to avoid extra negations. */ | ||
| 185 | 824511328 | z5 = MULTIPLY(tmp10 - tmp12, FIX_0_382683433); /* c6 */ | |
| 186 | 824511328 | z2 = MULTIPLY(tmp10, FIX_0_541196100) + z5; /* c2-c6 */ | |
| 187 | 824511328 | z4 = MULTIPLY(tmp12, FIX_1_306562965) + z5; /* c2+c6 */ | |
| 188 | 824511328 | z3 = MULTIPLY(tmp11, FIX_0_707106781); /* c4 */ | |
| 189 | |||
| 190 | 824511328 | z11 = tmp7 + z3; /* phase 5 */ | |
| 191 | 824511328 | z13 = tmp7 - z3; | |
| 192 | |||
| 193 | 824511328 | dataptr[5] = z13 + z2; /* phase 6 */ | |
| 194 | 824511328 | dataptr[3] = z13 - z2; | |
| 195 | 824511328 | dataptr[1] = z11 + z4; | |
| 196 | 824511328 | dataptr[7] = z11 - z4; | |
| 197 | |||
| 198 | 824511328 | dataptr += DCTSIZE; /* advance pointer to next row */ | |
| 199 | } | ||
| 200 | 103063916 | } | |
| 201 | |||
| 202 | /* | ||
| 203 | * Perform the forward DCT on one block of samples. | ||
| 204 | */ | ||
| 205 | |||
| 206 | GLOBAL(void) | ||
| 207 | 103063916 | ff_fdct_ifast (int16_t * data) | |
| 208 | { | ||
| 209 | int tmp0, tmp1, tmp2, tmp3, tmp4, tmp5, tmp6, tmp7; | ||
| 210 | int tmp10, tmp11, tmp12, tmp13; | ||
| 211 | int z1, z2, z3, z4, z5, z11, z13; | ||
| 212 | int16_t *dataptr; | ||
| 213 | int ctr; | ||
| 214 | |||
| 215 | 103063916 | row_fdct(data); | |
| 216 | |||
| 217 | /* Pass 2: process columns. */ | ||
| 218 | |||
| 219 | 103063916 | dataptr = data; | |
| 220 |
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927575244 | for (ctr = DCTSIZE-1; ctr >= 0; ctr--) { |
| 221 | 824511328 | tmp0 = dataptr[DCTSIZE*0] + dataptr[DCTSIZE*7]; | |
| 222 | 824511328 | tmp7 = dataptr[DCTSIZE*0] - dataptr[DCTSIZE*7]; | |
| 223 | 824511328 | tmp1 = dataptr[DCTSIZE*1] + dataptr[DCTSIZE*6]; | |
| 224 | 824511328 | tmp6 = dataptr[DCTSIZE*1] - dataptr[DCTSIZE*6]; | |
| 225 | 824511328 | tmp2 = dataptr[DCTSIZE*2] + dataptr[DCTSIZE*5]; | |
| 226 | 824511328 | tmp5 = dataptr[DCTSIZE*2] - dataptr[DCTSIZE*5]; | |
| 227 | 824511328 | tmp3 = dataptr[DCTSIZE*3] + dataptr[DCTSIZE*4]; | |
| 228 | 824511328 | tmp4 = dataptr[DCTSIZE*3] - dataptr[DCTSIZE*4]; | |
| 229 | |||
| 230 | /* Even part */ | ||
| 231 | |||
| 232 | 824511328 | tmp10 = tmp0 + tmp3; /* phase 2 */ | |
| 233 | 824511328 | tmp13 = tmp0 - tmp3; | |
| 234 | 824511328 | tmp11 = tmp1 + tmp2; | |
| 235 | 824511328 | tmp12 = tmp1 - tmp2; | |
| 236 | |||
| 237 | 824511328 | dataptr[DCTSIZE*0] = tmp10 + tmp11; /* phase 3 */ | |
| 238 | 824511328 | dataptr[DCTSIZE*4] = tmp10 - tmp11; | |
| 239 | |||
| 240 | 824511328 | z1 = MULTIPLY(tmp12 + tmp13, FIX_0_707106781); /* c4 */ | |
| 241 | 824511328 | dataptr[DCTSIZE*2] = tmp13 + z1; /* phase 5 */ | |
| 242 | 824511328 | dataptr[DCTSIZE*6] = tmp13 - z1; | |
| 243 | |||
| 244 | /* Odd part */ | ||
| 245 | |||
| 246 | 824511328 | tmp10 = tmp4 + tmp5; /* phase 2 */ | |
| 247 | 824511328 | tmp11 = tmp5 + tmp6; | |
| 248 | 824511328 | tmp12 = tmp6 + tmp7; | |
| 249 | |||
| 250 | /* The rotator is modified from fig 4-8 to avoid extra negations. */ | ||
| 251 | 824511328 | z5 = MULTIPLY(tmp10 - tmp12, FIX_0_382683433); /* c6 */ | |
| 252 | 824511328 | z2 = MULTIPLY(tmp10, FIX_0_541196100) + z5; /* c2-c6 */ | |
| 253 | 824511328 | z4 = MULTIPLY(tmp12, FIX_1_306562965) + z5; /* c2+c6 */ | |
| 254 | 824511328 | z3 = MULTIPLY(tmp11, FIX_0_707106781); /* c4 */ | |
| 255 | |||
| 256 | 824511328 | z11 = tmp7 + z3; /* phase 5 */ | |
| 257 | 824511328 | z13 = tmp7 - z3; | |
| 258 | |||
| 259 | 824511328 | dataptr[DCTSIZE*5] = z13 + z2; /* phase 6 */ | |
| 260 | 824511328 | dataptr[DCTSIZE*3] = z13 - z2; | |
| 261 | 824511328 | dataptr[DCTSIZE*1] = z11 + z4; | |
| 262 | 824511328 | dataptr[DCTSIZE*7] = z11 - z4; | |
| 263 | |||
| 264 | 824511328 | dataptr++; /* advance pointer to next column */ | |
| 265 | } | ||
| 266 | 103063916 | } | |
| 267 | |||
| 268 | /* | ||
| 269 | * Perform the forward 2-4-8 DCT on one block of samples. | ||
| 270 | */ | ||
| 271 | |||
| 272 | GLOBAL(void) | ||
| 273 | ✗ | ff_fdct_ifast248 (int16_t * data) | |
| 274 | { | ||
| 275 | int tmp0, tmp1, tmp2, tmp3, tmp4, tmp5, tmp6, tmp7; | ||
| 276 | int tmp10, tmp11, tmp12, tmp13; | ||
| 277 | int z1; | ||
| 278 | int16_t *dataptr; | ||
| 279 | int ctr; | ||
| 280 | |||
| 281 | ✗ | row_fdct(data); | |
| 282 | |||
| 283 | /* Pass 2: process columns. */ | ||
| 284 | |||
| 285 | ✗ | dataptr = data; | |
| 286 | ✗ | for (ctr = DCTSIZE-1; ctr >= 0; ctr--) { | |
| 287 | ✗ | tmp0 = dataptr[DCTSIZE*0] + dataptr[DCTSIZE*1]; | |
| 288 | ✗ | tmp1 = dataptr[DCTSIZE*2] + dataptr[DCTSIZE*3]; | |
| 289 | ✗ | tmp2 = dataptr[DCTSIZE*4] + dataptr[DCTSIZE*5]; | |
| 290 | ✗ | tmp3 = dataptr[DCTSIZE*6] + dataptr[DCTSIZE*7]; | |
| 291 | ✗ | tmp4 = dataptr[DCTSIZE*0] - dataptr[DCTSIZE*1]; | |
| 292 | ✗ | tmp5 = dataptr[DCTSIZE*2] - dataptr[DCTSIZE*3]; | |
| 293 | ✗ | tmp6 = dataptr[DCTSIZE*4] - dataptr[DCTSIZE*5]; | |
| 294 | ✗ | tmp7 = dataptr[DCTSIZE*6] - dataptr[DCTSIZE*7]; | |
| 295 | |||
| 296 | /* Even part */ | ||
| 297 | |||
| 298 | ✗ | tmp10 = tmp0 + tmp3; | |
| 299 | ✗ | tmp11 = tmp1 + tmp2; | |
| 300 | ✗ | tmp12 = tmp1 - tmp2; | |
| 301 | ✗ | tmp13 = tmp0 - tmp3; | |
| 302 | |||
| 303 | ✗ | dataptr[DCTSIZE*0] = tmp10 + tmp11; | |
| 304 | ✗ | dataptr[DCTSIZE*4] = tmp10 - tmp11; | |
| 305 | |||
| 306 | ✗ | z1 = MULTIPLY(tmp12 + tmp13, FIX_0_707106781); | |
| 307 | ✗ | dataptr[DCTSIZE*2] = tmp13 + z1; | |
| 308 | ✗ | dataptr[DCTSIZE*6] = tmp13 - z1; | |
| 309 | |||
| 310 | ✗ | tmp10 = tmp4 + tmp7; | |
| 311 | ✗ | tmp11 = tmp5 + tmp6; | |
| 312 | ✗ | tmp12 = tmp5 - tmp6; | |
| 313 | ✗ | tmp13 = tmp4 - tmp7; | |
| 314 | |||
| 315 | ✗ | dataptr[DCTSIZE*1] = tmp10 + tmp11; | |
| 316 | ✗ | dataptr[DCTSIZE*5] = tmp10 - tmp11; | |
| 317 | |||
| 318 | ✗ | z1 = MULTIPLY(tmp12 + tmp13, FIX_0_707106781); | |
| 319 | ✗ | dataptr[DCTSIZE*3] = tmp13 + z1; | |
| 320 | ✗ | dataptr[DCTSIZE*7] = tmp13 - z1; | |
| 321 | |||
| 322 | ✗ | dataptr++; /* advance pointer to next column */ | |
| 323 | } | ||
| 324 | ✗ | } | |
| 325 | |||
| 326 | |||
| 327 | #undef GLOBAL | ||
| 328 | #undef CONST_BITS | ||
| 329 | #undef DESCALE | ||
| 330 | #undef FIX_0_541196100 | ||
| 331 | #undef FIX_1_306562965 | ||
| 332 |