| 1 | /* |
| 2 | * Xvid MPEG-4 IDCT |
| 3 | * |
| 4 | * Copyright (C) 2006-2011 Xvid Solutions GmbH |
| 5 | * |
| 6 | * This file is part of FFmpeg. |
| 7 | * |
| 8 | * FFmpeg is free software; you can redistribute it and/or |
| 9 | * modify it under the terms of the GNU Lesser General Public |
| 10 | * License as published by the Free Software Foundation; either |
| 11 | * version 2.1 of the License, or (at your option) any later version. |
| 12 | * |
| 13 | * FFmpeg is distributed in the hope that it will be useful, |
| 14 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 15 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| 16 | * Lesser General Public License for more details. |
| 17 | * |
| 18 | * You should have received a copy of the GNU Lesser General Public |
| 19 | * License along with FFmpeg; if not, write to the Free Software |
| 20 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
| 21 | */ |
| 22 | |
| 23 | /** |
| 24 | * @file |
| 25 | * Walken IDCT |
| 26 | * Alternative IDCT implementation for decoding compatibility. |
| 27 | * |
| 28 | * @author Skal |
| 29 | * @note This C version is not the original IDCT, but a modified one that |
| 30 | * yields the same error profile as the MMX/MMXEXT/SSE2 versions. |
| 31 | */ |
| 32 | |
| 33 | #include "config.h" |
| 34 | #include "libavutil/attributes.h" |
| 35 | #include "avcodec.h" |
| 36 | #include "idctdsp.h" |
| 37 | #include "xvididct.h" |
| 38 | |
| 39 | #define ROW_SHIFT 11 |
| 40 | #define COL_SHIFT 6 |
| 41 | |
| 42 | // #define FIX(x) (int)((x) * (1 << ROW_SHIFT)) |
| 43 | #define RND0 65536 // 1 << (COL_SHIFT + ROW_SHIFT - 1); |
| 44 | #define RND1 3597 // FIX (1.75683487303); |
| 45 | #define RND2 2260 // FIX (1.10355339059); |
| 46 | #define RND3 1203 // FIX (0.587788325588); |
| 47 | #define RND4 0 |
| 48 | #define RND5 120 // FIX (0.058658283817); |
| 49 | #define RND6 512 // FIX (0.25); |
| 50 | #define RND7 512 // FIX (0.25); |
| 51 | |
| 52 | static const int TAB04[] = { 22725, 21407, 19266, 16384, 12873, 8867, 4520 }; |
| 53 | static const int TAB17[] = { 31521, 29692, 26722, 22725, 17855, 12299, 6270 }; |
| 54 | static const int TAB26[] = { 29692, 27969, 25172, 21407, 16819, 11585, 5906 }; |
| 55 | static const int TAB35[] = { 26722, 25172, 22654, 19266, 15137, 10426, 5315 }; |
| 56 | |
| 57 | static int idct_row(short *in, const int *const tab, int rnd) |
| 58 | { |
| 59 | const int c1 = tab[0]; |
| 60 | const int c2 = tab[1]; |
| 61 | const int c3 = tab[2]; |
| 62 | const int c4 = tab[3]; |
| 63 | const int c5 = tab[4]; |
| 64 | const int c6 = tab[5]; |
| 65 | const int c7 = tab[6]; |
| 66 | |
| 67 | const int right = in[5] | in[6] | in[7]; |
| 68 | const int left = in[1] | in[2] | in[3]; |
| 69 | if (!(right | in[4])) { |
| 70 | const int k = c4 * in[0] + rnd; |
| 71 | if (left) { |
| 72 | const int a0 = k + c2 * in[2]; |
| 73 | const int a1 = k + c6 * in[2]; |
| 74 | const int a2 = k - c6 * in[2]; |
| 75 | const int a3 = k - c2 * in[2]; |
| 76 | |
| 77 | const int b0 = c1 * in[1] + c3 * in[3]; |
| 78 | const int b1 = c3 * in[1] - c7 * in[3]; |
| 79 | const int b2 = c5 * in[1] - c1 * in[3]; |
| 80 | const int b3 = c7 * in[1] - c5 * in[3]; |
| 81 | |
| 82 | in[0] = (a0 + b0) >> ROW_SHIFT; |
| 83 | in[1] = (a1 + b1) >> ROW_SHIFT; |
| 84 | in[2] = (a2 + b2) >> ROW_SHIFT; |
| 85 | in[3] = (a3 + b3) >> ROW_SHIFT; |
| 86 | in[4] = (a3 - b3) >> ROW_SHIFT; |
| 87 | in[5] = (a2 - b2) >> ROW_SHIFT; |
| 88 | in[6] = (a1 - b1) >> ROW_SHIFT; |
| 89 | in[7] = (a0 - b0) >> ROW_SHIFT; |
| 90 | } else { |
| 91 | const int a0 = k >> ROW_SHIFT; |
| 92 | if (a0) { |
| 93 | in[0] = |
| 94 | in[1] = |
| 95 | in[2] = |
| 96 | in[3] = |
| 97 | in[4] = |
| 98 | in[5] = |
| 99 | in[6] = |
| 100 | in[7] = a0; |
| 101 | } else |
| 102 | return 0; |
| 103 | } |
| 104 | } else if (!(left | right)) { |
| 105 | const int a0 = (rnd + c4 * (in[0] + in[4])) >> ROW_SHIFT; |
| 106 | const int a1 = (rnd + c4 * (in[0] - in[4])) >> ROW_SHIFT; |
| 107 | |
| 108 | in[0] = a0; |
| 109 | in[3] = a0; |
| 110 | in[4] = a0; |
| 111 | in[7] = a0; |
| 112 | in[1] = a1; |
| 113 | in[2] = a1; |
| 114 | in[5] = a1; |
| 115 | in[6] = a1; |
| 116 | } else { |
| 117 | const int k = c4 * in[0] + rnd; |
| 118 | const int a0 = k + c2 * in[2] + c4 * in[4] + c6 * in[6]; |
| 119 | const int a1 = k + c6 * in[2] - c4 * in[4] - c2 * in[6]; |
| 120 | const int a2 = k - c6 * in[2] - c4 * in[4] + c2 * in[6]; |
| 121 | const int a3 = k - c2 * in[2] + c4 * in[4] - c6 * in[6]; |
| 122 | |
| 123 | const int b0 = c1 * in[1] + c3 * in[3] + c5 * in[5] + c7 * in[7]; |
| 124 | const int b1 = c3 * in[1] - c7 * in[3] - c1 * in[5] - c5 * in[7]; |
| 125 | const int b2 = c5 * in[1] - c1 * in[3] + c7 * in[5] + c3 * in[7]; |
| 126 | const int b3 = c7 * in[1] - c5 * in[3] + c3 * in[5] - c1 * in[7]; |
| 127 | |
| 128 | in[0] = (a0 + b0) >> ROW_SHIFT; |
| 129 | in[1] = (a1 + b1) >> ROW_SHIFT; |
| 130 | in[2] = (a2 + b2) >> ROW_SHIFT; |
| 131 | in[3] = (a3 + b3) >> ROW_SHIFT; |
| 132 | in[4] = (a3 - b3) >> ROW_SHIFT; |
| 133 | in[5] = (a2 - b2) >> ROW_SHIFT; |
| 134 | in[6] = (a1 - b1) >> ROW_SHIFT; |
| 135 | in[7] = (a0 - b0) >> ROW_SHIFT; |
| 136 | } |
| 137 | return 1; |
| 138 | } |
| 139 | |
| 140 | #define TAN1 0x32EC |
| 141 | #define TAN2 0x6A0A |
| 142 | #define TAN3 0xAB0E |
| 143 | #define SQRT2 0x5A82 |
| 144 | |
| 145 | #define MULT(c, x, n) (((c) * (x)) >> (n)) |
| 146 | // 12b version => #define MULT(c,x, n) ((((c) >> 3) * (x)) >> ((n) - 3)) |
| 147 | // 12b zero-testing version: |
| 148 | |
| 149 | #define BUTTERFLY(a, b, tmp) \ |
| 150 | (tmp) = (a) + (b); \ |
| 151 | (b) = (a) - (b); \ |
| 152 | (a) = (tmp) |
| 153 | |
| 154 | #define LOAD_BUTTERFLY(m1, m2, a, b, tmp, s) \ |
| 155 | (m1) = (s)[(a)] + (s)[(b)]; \ |
| 156 | (m2) = (s)[(a)] - (s)[(b)] |
| 157 | |
| 158 | static void idct_col_8(short *const in) |
| 159 | { |
| 160 | int mm0, mm1, mm2, mm3, mm4, mm5, mm6, mm7, spill; |
| 161 | |
| 162 | // odd |
| 163 | |
| 164 | mm4 = (int) in[7 * 8]; |
| 165 | mm5 = (int) in[5 * 8]; |
| 166 | mm6 = (int) in[3 * 8]; |
| 167 | mm7 = (int) in[1 * 8]; |
| 168 | |
| 169 | mm0 = MULT(TAN1, mm4, 16) + mm7; |
| 170 | mm1 = MULT(TAN1, mm7, 16) - mm4; |
| 171 | mm2 = MULT(TAN3, mm5, 16) + mm6; |
| 172 | mm3 = MULT(TAN3, mm6, 16) - mm5; |
| 173 | |
| 174 | mm7 = mm0 + mm2; |
| 175 | mm4 = mm1 - mm3; |
| 176 | mm0 = mm0 - mm2; |
| 177 | mm1 = mm1 + mm3; |
| 178 | mm6 = mm0 + mm1; |
| 179 | mm5 = mm0 - mm1; |
| 180 | mm5 = 2 * MULT(SQRT2, mm5, 16); // 2*sqrt2 |
| 181 | mm6 = 2 * MULT(SQRT2, mm6, 16); // Watch out: precision loss but done to match |
| 182 | // the pmulhw used in MMX/MMXEXT/SSE2 versions |
| 183 | |
| 184 | // even |
| 185 | |
| 186 | mm1 = (int) in[2 * 8]; |
| 187 | mm2 = (int) in[6 * 8]; |
| 188 | mm3 = MULT(TAN2, mm2, 16) + mm1; |
| 189 | mm2 = MULT(TAN2, mm1, 16) - mm2; |
| 190 | |
| 191 | LOAD_BUTTERFLY(mm0, mm1, 0 * 8, 4 * 8, spill, in); |
| 192 | |
| 193 | BUTTERFLY(mm0, mm3, spill); |
| 194 | BUTTERFLY(mm0, mm7, spill); |
| 195 | in[8 * 0] = (int16_t) (mm0 >> COL_SHIFT); |
| 196 | in[8 * 7] = (int16_t) (mm7 >> COL_SHIFT); |
| 197 | BUTTERFLY(mm3, mm4, mm0); |
| 198 | in[8 * 3] = (int16_t) (mm3 >> COL_SHIFT); |
| 199 | in[8 * 4] = (int16_t) (mm4 >> COL_SHIFT); |
| 200 | |
| 201 | BUTTERFLY(mm1, mm2, mm0); |
| 202 | BUTTERFLY(mm1, mm6, mm0); |
| 203 | in[8 * 1] = (int16_t) (mm1 >> COL_SHIFT); |
| 204 | in[8 * 6] = (int16_t) (mm6 >> COL_SHIFT); |
| 205 | BUTTERFLY(mm2, mm5, mm0); |
| 206 | in[8 * 2] = (int16_t) (mm2 >> COL_SHIFT); |
| 207 | in[8 * 5] = (int16_t) (mm5 >> COL_SHIFT); |
| 208 | } |
| 209 | |
| 210 | static void idct_col_4(short *const in) |
| 211 | { |
| 212 | int mm0, mm1, mm2, mm3, mm4, mm5, mm6, mm7, spill; |
| 213 | |
| 214 | // odd |
| 215 | |
| 216 | mm0 = (int) in[1 * 8]; |
| 217 | mm2 = (int) in[3 * 8]; |
| 218 | |
| 219 | mm1 = MULT(TAN1, mm0, 16); |
| 220 | mm3 = MULT(TAN3, mm2, 16); |
| 221 | |
| 222 | mm7 = mm0 + mm2; |
| 223 | mm4 = mm1 - mm3; |
| 224 | mm0 = mm0 - mm2; |
| 225 | mm1 = mm1 + mm3; |
| 226 | mm6 = mm0 + mm1; |
| 227 | mm5 = mm0 - mm1; |
| 228 | mm6 = 2 * MULT(SQRT2, mm6, 16); // 2*sqrt2 |
| 229 | mm5 = 2 * MULT(SQRT2, mm5, 16); |
| 230 | |
| 231 | // even |
| 232 | |
| 233 | mm0 = mm1 = (int) in[0 * 8]; |
| 234 | mm3 = (int) in[2 * 8]; |
| 235 | mm2 = MULT(TAN2, mm3, 16); |
| 236 | |
| 237 | BUTTERFLY(mm0, mm3, spill); |
| 238 | BUTTERFLY(mm0, mm7, spill); |
| 239 | in[8 * 0] = (int16_t) (mm0 >> COL_SHIFT); |
| 240 | in[8 * 7] = (int16_t) (mm7 >> COL_SHIFT); |
| 241 | BUTTERFLY(mm3, mm4, mm0); |
| 242 | in[8 * 3] = (int16_t) (mm3 >> COL_SHIFT); |
| 243 | in[8 * 4] = (int16_t) (mm4 >> COL_SHIFT); |
| 244 | |
| 245 | BUTTERFLY(mm1, mm2, mm0); |
| 246 | BUTTERFLY(mm1, mm6, mm0); |
| 247 | in[8 * 1] = (int16_t) (mm1 >> COL_SHIFT); |
| 248 | in[8 * 6] = (int16_t) (mm6 >> COL_SHIFT); |
| 249 | BUTTERFLY(mm2, mm5, mm0); |
| 250 | in[8 * 2] = (int16_t) (mm2 >> COL_SHIFT); |
| 251 | in[8 * 5] = (int16_t) (mm5 >> COL_SHIFT); |
| 252 | } |
| 253 | |
| 254 | static void idct_col_3(short *const in) |
| 255 | { |
| 256 | int mm0, mm1, mm2, mm3, mm4, mm5, mm6, mm7, spill; |
| 257 | |
| 258 | // odd |
| 259 | |
| 260 | mm7 = (int) in[1 * 8]; |
| 261 | mm4 = MULT(TAN1, mm7, 16); |
| 262 | |
| 263 | mm6 = mm7 + mm4; |
| 264 | mm5 = mm7 - mm4; |
| 265 | mm6 = 2 * MULT(SQRT2, mm6, 16); // 2*sqrt2 |
| 266 | mm5 = 2 * MULT(SQRT2, mm5, 16); |
| 267 | |
| 268 | // even |
| 269 | |
| 270 | mm0 = mm1 = (int) in[0 * 8]; |
| 271 | mm3 = (int) in[2 * 8]; |
| 272 | mm2 = MULT(TAN2, mm3, 16); |
| 273 | |
| 274 | BUTTERFLY(mm0, mm3, spill); |
| 275 | BUTTERFLY(mm0, mm7, spill); |
| 276 | in[8 * 0] = (int16_t) (mm0 >> COL_SHIFT); |
| 277 | in[8 * 7] = (int16_t) (mm7 >> COL_SHIFT); |
| 278 | BUTTERFLY(mm3, mm4, mm0); |
| 279 | in[8 * 3] = (int16_t) (mm3 >> COL_SHIFT); |
| 280 | in[8 * 4] = (int16_t) (mm4 >> COL_SHIFT); |
| 281 | |
| 282 | BUTTERFLY(mm1, mm2, mm0); |
| 283 | BUTTERFLY(mm1, mm6, mm0); |
| 284 | in[8 * 1] = (int16_t) (mm1 >> COL_SHIFT); |
| 285 | in[8 * 6] = (int16_t) (mm6 >> COL_SHIFT); |
| 286 | BUTTERFLY(mm2, mm5, mm0); |
| 287 | in[8 * 2] = (int16_t) (mm2 >> COL_SHIFT); |
| 288 | in[8 * 5] = (int16_t) (mm5 >> COL_SHIFT); |
| 289 | } |
| 290 | |
| 291 | void ff_xvid_idct(int16_t *const in) |
| 292 | { |
| 293 | int i, rows = 0x07; |
| 294 | |
| 295 | idct_row(in + 0 * 8, TAB04, RND0); |
| 296 | idct_row(in + 1 * 8, TAB17, RND1); |
| 297 | idct_row(in + 2 * 8, TAB26, RND2); |
| 298 | if (idct_row(in + 3 * 8, TAB35, RND3)) |
| 299 | rows |= 0x08; |
| 300 | if (idct_row(in + 4 * 8, TAB04, RND4)) |
| 301 | rows |= 0x10; |
| 302 | if (idct_row(in + 5 * 8, TAB35, RND5)) |
| 303 | rows |= 0x20; |
| 304 | if (idct_row(in + 6 * 8, TAB26, RND6)) |
| 305 | rows |= 0x40; |
| 306 | if (idct_row(in + 7 * 8, TAB17, RND7)) |
| 307 | rows |= 0x80; |
| 308 | |
| 309 | if (rows & 0xF0) { |
| 310 | for (i = 0; i < 8; i++) |
| 311 | idct_col_8(in + i); |
| 312 | } else if (rows & 0x08) { |
| 313 | for (i = 0; i < 8; i++) |
| 314 | idct_col_4(in + i); |
| 315 | } else { |
| 316 | for (i = 0; i < 8; i++) |
| 317 | idct_col_3(in + i); |
| 318 | } |
| 319 | } |
| 320 | |
| 321 | static void xvid_idct_put(uint8_t *dest, int line_size, int16_t *block) |
| 322 | { |
| 323 | ff_xvid_idct(block); |
| 324 | ff_put_pixels_clamped(block, dest, line_size); |
| 325 | } |
| 326 | |
| 327 | static void xvid_idct_add(uint8_t *dest, int line_size, int16_t *block) |
| 328 | { |
| 329 | ff_xvid_idct(block); |
| 330 | ff_add_pixels_clamped(block, dest, line_size); |
| 331 | } |
| 332 | |
| 333 | av_cold void ff_xvid_idct_init(IDCTDSPContext *c, AVCodecContext *avctx) |
| 334 | { |
| 335 | const unsigned high_bit_depth = avctx->bits_per_raw_sample > 8; |
| 336 | |
| 337 | if (high_bit_depth || avctx->lowres || |
| 338 | !(avctx->idct_algo == FF_IDCT_AUTO || |
| 339 | avctx->idct_algo == FF_IDCT_XVID)) |
| 340 | return; |
| 341 | |
| 342 | if (avctx->idct_algo == FF_IDCT_XVID) { |
| 343 | c->idct_put = xvid_idct_put; |
| 344 | c->idct_add = xvid_idct_add; |
| 345 | c->idct = ff_xvid_idct; |
| 346 | c->perm_type = FF_IDCT_PERM_NONE; |
| 347 | } |
| 348 | |
| 349 | if (ARCH_X86) |
| 350 | ff_xvid_idct_init_x86(c, avctx, high_bit_depth); |
| 351 | |
| 352 | ff_init_scantable_permutation(c->idct_permutation, c->perm_type); |
| 353 | } |