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| | 1 | /* |
| | 2 | * Microsoft Screen 1 (aka Windows Media Video V7 Screen) decoder |
| | 3 | * Copyright (c) 2012 Konstantin Shishkov |
| | 4 | * |
| | 5 | * This file is part of Libav. |
| | 6 | * |
| | 7 | * Libav is free software; you can redistribute it and/or |
| | 8 | * modify it under the terms of the GNU Lesser General Public |
| | 9 | * License as published by the Free Software Foundation; either |
| | 10 | * version 2.1 of the License, or (at your option) any later version. |
| | 11 | * |
| | 12 | * Libav is distributed in the hope that it will be useful, |
| | 13 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| | 14 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| | 15 | * Lesser General Public License for more details. |
| | 16 | * |
| | 17 | * You should have received a copy of the GNU Lesser General Public |
| | 18 | * License along with Libav; if not, write to the Free Software |
| | 19 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
| | 20 | */ |
| | 21 | |
| | 22 | /** |
| | 23 | * @file |
| | 24 | * Microsoft Screen 1 (aka Windows Media Video V7 Screen) decoder |
| | 25 | */ |
| | 26 | |
| | 27 | #include "libavutil/intfloat.h" |
| | 28 | #include "libavutil/intreadwrite.h" |
| | 29 | #include "avcodec.h" |
| | 30 | #include "get_bits.h" |
| | 31 | |
| | 32 | enum SplitMode { |
| | 33 | SPLIT_VERT = 0, |
| | 34 | SPLIT_HOR, |
| | 35 | SPLIT_NONE |
| | 36 | }; |
| | 37 | |
| | 38 | typedef struct ArithCoder { |
| | 39 | int low, high, value; |
| | 40 | GetBitContext *gb; |
| | 41 | } ArithCoder; |
| | 42 | |
| | 43 | #define MODEL_MIN_SYMS 2 |
| | 44 | #define MODEL_MAX_SYMS 256 |
| | 45 | #define THRESH_ADAPTIVE -1 |
| | 46 | #define THRESH_LOW 15 |
| | 47 | #define THRESH_HIGH 50 |
| | 48 | |
| | 49 | typedef struct Model { |
| | 50 | int cum_prob[MODEL_MAX_SYMS + 1]; |
| | 51 | int weights[MODEL_MAX_SYMS + 1]; |
| | 52 | int idx2sym[MODEL_MAX_SYMS + 1]; |
| | 53 | int sym2idx[MODEL_MAX_SYMS + 1]; |
| | 54 | int num_syms; |
| | 55 | int thr_weight, threshold; |
| | 56 | } Model; |
| | 57 | |
| | 58 | static const int sec_order_sizes[4] = { 1, 7, 6, 1 }; |
| | 59 | |
| | 60 | enum ContextDirection { |
| | 61 | TOP_LEFT = 0, |
| | 62 | TOP, |
| | 63 | TOP_RIGHT, |
| | 64 | LEFT |
| | 65 | }; |
| | 66 | |
| | 67 | typedef struct PixContext { |
| | 68 | int cache_size, num_syms; |
| | 69 | uint8_t cache[12]; |
| | 70 | Model cache_model, full_model; |
| | 71 | Model sec_models[4][8][4]; |
| | 72 | } PixContext; |
| | 73 | |
| | 74 | typedef struct MSS1Context { |
| | 75 | AVCodecContext *avctx; |
| | 76 | AVFrame pic; |
| | 77 | uint8_t *pic_start; |
| | 78 | int pic_stride; |
| | 79 | uint8_t *mask; |
| | 80 | int mask_linesize; |
| | 81 | uint32_t pal[256]; |
| | 82 | int free_colours; |
| | 83 | Model intra_region, inter_region; |
| | 84 | Model pivot, edge_mode, split_mode; |
| | 85 | PixContext intra_pix_ctx, inter_pix_ctx; |
| | 86 | int corrupted; |
| | 87 | } MSS1Context; |
| | 88 | |
| | 89 | static void arith_init(ArithCoder *c, GetBitContext *gb) |
| | 90 | { |
| | 91 | c->low = 0; |
| | 92 | c->high = 0xFFFF; |
| | 93 | c->value = get_bits(gb, 16); |
| | 94 | c->gb = gb; |
| | 95 | } |
| | 96 | |
| | 97 | static void arith_normalise(ArithCoder *c) |
| | 98 | { |
| | 99 | for (;;) { |
| | 100 | if (c->high >= 0x8000) { |
| | 101 | if (c->low < 0x8000) { |
| | 102 | if (c->low >= 0x4000 && c->high < 0xC000) { |
| | 103 | c->value -= 0x4000; |
| | 104 | c->low -= 0x4000; |
| | 105 | c->high -= 0x4000; |
| | 106 | } else { |
| | 107 | return; |
| | 108 | } |
| | 109 | } else { |
| | 110 | c->value -= 0x8000; |
| | 111 | c->low -= 0x8000; |
| | 112 | c->high -= 0x8000; |
| | 113 | } |
| | 114 | } |
| | 115 | c->value <<= 1; |
| | 116 | c->low <<= 1; |
| | 117 | c->high <<= 1; |
| | 118 | c->high |= 1; |
| | 119 | c->value |= get_bits1(c->gb); |
| | 120 | } |
| | 121 | } |
| | 122 | |
| | 123 | static int arith_get_bit(ArithCoder *c) |
| | 124 | { |
| | 125 | int range = c->high - c->low + 1; |
| | 126 | int bit = (((c->value - c->low) << 1) + 1) / range; |
| | 127 | |
| | 128 | if (bit) |
| | 129 | c->low += range >> 1; |
| | 130 | else |
| | 131 | c->high = c->low + (range >> 1) - 1; |
| | 132 | |
| | 133 | arith_normalise(c); |
| | 134 | |
| | 135 | return bit; |
| | 136 | } |
| | 137 | |
| | 138 | static int arith_get_bits(ArithCoder *c, int bits) |
| | 139 | { |
| | 140 | int range = c->high - c->low + 1; |
| | 141 | int val = (((c->value - c->low + 1) << bits) - 1) / range; |
| | 142 | int prob = range * val; |
| | 143 | |
| | 144 | c->high = ((prob + range) >> bits) + c->low - 1; |
| | 145 | c->low += prob >> bits; |
| | 146 | |
| | 147 | arith_normalise(c); |
| | 148 | |
| | 149 | return val; |
| | 150 | } |
| | 151 | |
| | 152 | static int arith_get_number(ArithCoder *c, int mod_val) |
| | 153 | { |
| | 154 | int range = c->high - c->low + 1; |
| | 155 | int val = ((c->value - c->low + 1) * mod_val - 1) / range; |
| | 156 | int prob = range * val; |
| | 157 | |
| | 158 | c->high = (prob + range) / mod_val + c->low - 1; |
| | 159 | c->low += prob / mod_val; |
| | 160 | |
| | 161 | arith_normalise(c); |
| | 162 | |
| | 163 | return val; |
| | 164 | } |
| | 165 | |
| | 166 | static int arith_get_prob(ArithCoder *c, int *probs) |
| | 167 | { |
| | 168 | int range = c->high - c->low + 1; |
| | 169 | int val = ((c->value - c->low + 1) * probs[0] - 1) / range; |
| | 170 | int sym = 1; |
| | 171 | |
| | 172 | while (probs[sym] > val) |
| | 173 | sym++; |
| | 174 | |
| | 175 | c->high = range * probs[sym - 1] / probs[0] + c->low - 1; |
| | 176 | c->low += range * probs[sym] / probs[0]; |
| | 177 | |
| | 178 | return sym; |
| | 179 | } |
| | 180 | |
| | 181 | static int model_calc_threshold(Model *m) |
| | 182 | { |
| | 183 | int thr; |
| | 184 | |
| | 185 | if (m->thr_weight == -1) { |
| | 186 | thr = 2 * m->weights[m->num_syms] - 1; |
| | 187 | thr = ((thr >> 1) + 4 * m->cum_prob[0]) / thr; |
| | 188 | } else { |
| | 189 | thr = m->num_syms * m->thr_weight; |
| | 190 | } |
| | 191 | |
| | 192 | return FFMIN(thr, 0x3FFF); |
| | 193 | } |
| | 194 | |
| | 195 | static void model_reset(Model *m) |
| | 196 | { |
| | 197 | int i; |
| | 198 | |
| | 199 | for (i = 0; i <= m->num_syms; i++) { |
| | 200 | m->weights[i] = 1; |
| | 201 | m->cum_prob[i] = m->num_syms - i; |
| | 202 | } |
| | 203 | m->weights[0] = -1; |
| | 204 | m->idx2sym[0] = -1; |
| | 205 | m->sym2idx[m->num_syms] = -1; |
| | 206 | for (i = 0; i < m->num_syms; i++) { |
| | 207 | m->sym2idx[i] = i + 1; |
| | 208 | m->idx2sym[i + 1] = i; |
| | 209 | } |
| | 210 | } |
| | 211 | |
| | 212 | static av_cold void model_init(Model *m, int num_syms, int thr_weight) |
| | 213 | { |
| | 214 | m->num_syms = num_syms; |
| | 215 | m->thr_weight = thr_weight; |
| | 216 | m->threshold = model_calc_threshold(m); |
| | 217 | model_reset(m); |
| | 218 | } |
| | 219 | |
| | 220 | static void model_rescale_weights(Model *m) |
| | 221 | { |
| | 222 | int i; |
| | 223 | int cum_prob; |
| | 224 | |
| | 225 | if (m->thr_weight == -1) |
| | 226 | m->threshold = model_calc_threshold(m); |
| | 227 | while (m->cum_prob[0] > m->threshold) { |
| | 228 | cum_prob = 0; |
| | 229 | for (i = m->num_syms; i >= 0; i--) { |
| | 230 | m->cum_prob[i] = cum_prob; |
| | 231 | m->weights[i] = (m->weights[i] + 1) >> 1; |
| | 232 | cum_prob += m->weights[i]; |
| | 233 | } |
| | 234 | } |
| | 235 | } |
| | 236 | |
| | 237 | static void model_update(Model *m, int val) |
| | 238 | { |
| | 239 | int i; |
| | 240 | |
| | 241 | if (m->weights[val] == m->weights[val - 1]) { |
| | 242 | for (i = val; m->weights[i - 1] == m->weights[val]; i--); |
| | 243 | if (i != val) { |
| | 244 | int sym1, sym2; |
| | 245 | |
| | 246 | sym1 = m->idx2sym[val]; |
| | 247 | sym2 = m->idx2sym[i]; |
| | 248 | |
| | 249 | m->idx2sym[val] = sym2; |
| | 250 | m->idx2sym[i] = sym1; |
| | 251 | m->sym2idx[sym1] = i; |
| | 252 | m->sym2idx[sym2] = val; |
| | 253 | |
| | 254 | val = i; |
| | 255 | } |
| | 256 | } |
| | 257 | m->weights[val]++; |
| | 258 | for (i = val - 1; i >= 0; i--) |
| | 259 | m->cum_prob[i]++; |
| | 260 | model_rescale_weights(m); |
| | 261 | } |
| | 262 | |
| | 263 | static int arith_get_model_sym(ArithCoder *c, Model *m) |
| | 264 | { |
| | 265 | int idx, val; |
| | 266 | |
| | 267 | idx = arith_get_prob(c, m->cum_prob); |
| | 268 | |
| | 269 | val = m->idx2sym[idx]; |
| | 270 | model_update(m, idx); |
| | 271 | |
| | 272 | arith_normalise(c); |
| | 273 | |
| | 274 | return val; |
| | 275 | } |
| | 276 | |
| | 277 | static void pixctx_reset(PixContext *ctx) |
| | 278 | { |
| | 279 | int i, j, k; |
| | 280 | |
| | 281 | for (i = 0; i < ctx->cache_size; i++) |
| | 282 | ctx->cache[i] = i; |
| | 283 | |
| | 284 | model_reset(&ctx->cache_model); |
| | 285 | model_reset(&ctx->full_model); |
| | 286 | |
| | 287 | for (i = 0; i < 4; i++) |
| | 288 | for (j = 0; j < sec_order_sizes[i]; j++) |
| | 289 | for (k = 0; k < 4; k++) |
| | 290 | model_reset(&ctx->sec_models[i][j][k]); |
| | 291 | } |
| | 292 | |
| | 293 | static av_cold void pixctx_init(PixContext *ctx, int cache_size) |
| | 294 | { |
| | 295 | int i, j, k; |
| | 296 | |
| | 297 | ctx->cache_size = cache_size + 4; |
| | 298 | ctx->num_syms = cache_size; |
| | 299 | |
| | 300 | for (i = 0; i < ctx->cache_size; i++) |
| | 301 | ctx->cache[i] = i; |
| | 302 | |
| | 303 | model_init(&ctx->cache_model, ctx->num_syms + 1, THRESH_LOW); |
| | 304 | model_init(&ctx->full_model, 256, THRESH_HIGH); |
| | 305 | |
| | 306 | for (i = 0; i < 4; i++) { |
| | 307 | for (j = 0; j < sec_order_sizes[i]; j++) { |
| | 308 | for (k = 0; k < 4; k++) { |
| | 309 | model_init(&ctx->sec_models[i][j][k], 2 + i, |
| | 310 | i ? THRESH_LOW : THRESH_ADAPTIVE); |
| | 311 | } |
| | 312 | } |
| | 313 | } |
| | 314 | } |
| | 315 | |
| | 316 | static int decode_top_left_pixel(ArithCoder *acoder, PixContext *pctx) |
| | 317 | { |
| | 318 | int i, val, pix; |
| | 319 | |
| | 320 | val = arith_get_model_sym(acoder, &pctx->cache_model); |
| | 321 | if (val < pctx->num_syms) { |
| | 322 | pix = pctx->cache[val]; |
| | 323 | } else { |
| | 324 | pix = arith_get_model_sym(acoder, &pctx->full_model); |
| | 325 | for (i = 0; i < pctx->cache_size - 1; i++) |
| | 326 | if (pctx->cache[i] == pix) |
| | 327 | break; |
| | 328 | val = i; |
| | 329 | } |
| | 330 | if (val) { |
| | 331 | for (i = val; i > 0; i--) |
| | 332 | pctx->cache[i] = pctx->cache[i - 1]; |
| | 333 | pctx->cache[0] = pix; |
| | 334 | } |
| | 335 | |
| | 336 | return pix; |
| | 337 | } |
| | 338 | |
| | 339 | static int decode_pixel(ArithCoder *acoder, PixContext *pctx, |
| | 340 | uint8_t *ngb, int num_ngb) |
| | 341 | { |
| | 342 | int i, val, pix; |
| | 343 | |
| | 344 | val = arith_get_model_sym(acoder, &pctx->cache_model); |
| | 345 | if (val < pctx->num_syms) { |
| | 346 | int idx, j; |
| | 347 | |
| | 348 | |
| | 349 | idx = 0; |
| | 350 | for (i = 0; i < pctx->cache_size; i++) { |
| | 351 | for (j = 0; j < num_ngb; j++) |
| | 352 | if (pctx->cache[i] == ngb[j]) |
| | 353 | break; |
| | 354 | if (j == num_ngb) { |
| | 355 | if (idx == val) |
| | 356 | break; |
| | 357 | idx++; |
| | 358 | } |
| | 359 | } |
| | 360 | val = FFMIN(i, pctx->cache_size - 1); |
| | 361 | pix = pctx->cache[val]; |
| | 362 | } else { |
| | 363 | pix = arith_get_model_sym(acoder, &pctx->full_model); |
| | 364 | for (i = 0; i < pctx->cache_size - 1; i++) |
| | 365 | if (pctx->cache[i] == pix) |
| | 366 | break; |
| | 367 | val = i; |
| | 368 | } |
| | 369 | if (val) { |
| | 370 | for (i = val; i > 0; i--) |
| | 371 | pctx->cache[i] = pctx->cache[i - 1]; |
| | 372 | pctx->cache[0] = pix; |
| | 373 | } |
| | 374 | |
| | 375 | return pix; |
| | 376 | } |
| | 377 | |
| | 378 | static int decode_pixel_in_context(ArithCoder *acoder, PixContext *pctx, |
| | 379 | uint8_t *src, int stride, int x, int y, |
| | 380 | int has_right) |
| | 381 | { |
| | 382 | uint8_t neighbours[4]; |
| | 383 | uint8_t ref_pix[4]; |
| | 384 | int nlen; |
| | 385 | int layer = 0, sub; |
| | 386 | int pix; |
| | 387 | int i, j; |
| | 388 | |
| | 389 | if (!y) { |
| | 390 | memset(neighbours, src[-1], 4); |
| | 391 | } else { |
| | 392 | neighbours[TOP] = src[-stride]; |
| | 393 | if (!x) { |
| | 394 | neighbours[TOP_LEFT] = neighbours[LEFT] = neighbours[TOP]; |
| | 395 | } else { |
| | 396 | neighbours[TOP_LEFT] = src[-stride - 1]; |
| | 397 | neighbours[ LEFT] = src[-1]; |
| | 398 | } |
| | 399 | if (has_right) |
| | 400 | neighbours[TOP_RIGHT] = src[-stride + 1]; |
| | 401 | else |
| | 402 | neighbours[TOP_RIGHT] = neighbours[TOP]; |
| | 403 | } |
| | 404 | |
| | 405 | sub = 0; |
| | 406 | if (x >= 2 && src[-2] == neighbours[LEFT]) |
| | 407 | sub = 1; |
| | 408 | if (y >= 2 && src[-2 * stride] == neighbours[TOP]) |
| | 409 | sub |= 2; |
| | 410 | |
| | 411 | nlen = 1; |
| | 412 | ref_pix[0] = neighbours[0]; |
| | 413 | for (i = 1; i < 4; i++) { |
| | 414 | for (j = 0; j < nlen; j++) |
| | 415 | if (ref_pix[j] == neighbours[i]) |
| | 416 | break; |
| | 417 | if (j == nlen) |
| | 418 | ref_pix[nlen++] = neighbours[i]; |
| | 419 | } |
| | 420 | |
| | 421 | switch (nlen) { |
| | 422 | case 1: |
| | 423 | case 4: |
| | 424 | layer = 0; |
| | 425 | break; |
| | 426 | case 2: |
| | 427 | if (neighbours[TOP] == neighbours[TOP_LEFT]) { |
| | 428 | if (neighbours[TOP_RIGHT] == neighbours[TOP_LEFT]) |
| | 429 | layer = 3; |
| | 430 | else if (neighbours[LEFT] == neighbours[TOP_LEFT]) |
| | 431 | layer = 2; |
| | 432 | else |
| | 433 | layer = 4; |
| | 434 | } else if (neighbours[TOP_RIGHT] == neighbours[TOP_LEFT]) { |
| | 435 | if (neighbours[LEFT] == neighbours[TOP_LEFT]) |
| | 436 | layer = 1; |
| | 437 | else |
| | 438 | layer = 5; |
| | 439 | } else if (neighbours[LEFT] == neighbours[TOP_LEFT]) { |
| | 440 | layer = 6; |
| | 441 | } else { |
| | 442 | layer = 0; |
| | 443 | } |
| | 444 | break; |
| | 445 | case 3: |
| | 446 | if (neighbours[TOP] == neighbours[TOP_LEFT]) |
| | 447 | layer = 0; |
| | 448 | else if (neighbours[TOP_RIGHT] == neighbours[TOP_LEFT]) |
| | 449 | layer = 1; |
| | 450 | else if (neighbours[LEFT] == neighbours[TOP_LEFT]) |
| | 451 | layer = 2; |
| | 452 | else if (neighbours[TOP_RIGHT] == neighbours[TOP]) |
| | 453 | layer = 3; |
| | 454 | else if (neighbours[TOP] == neighbours[LEFT]) |
| | 455 | layer = 4; |
| | 456 | else |
| | 457 | layer = 5; |
| | 458 | break; |
| | 459 | } |
| | 460 | |
| | 461 | pix = arith_get_model_sym(acoder, &pctx->sec_models[nlen - 1][layer][sub]); |
| | 462 | if (pix < nlen) |
| | 463 | return ref_pix[pix]; |
| | 464 | else |
| | 465 | return decode_pixel(acoder, pctx, ref_pix, nlen); |
| | 466 | } |
| | 467 | |
| | 468 | static int decode_region(MSS1Context *ctx, ArithCoder *acoder, uint8_t *dst, |
| | 469 | int x, int y, int width, int height, int stride, |
| | 470 | PixContext *pctx) |
| | 471 | { |
| | 472 | int i, j; |
| | 473 | |
| | 474 | dst += x + y * stride; |
| | 475 | |
| | 476 | dst[0] = decode_top_left_pixel(acoder, pctx); |
| | 477 | for (j = 0; j < height; j++) { |
| | 478 | for (i = 0; i < width; i++) { |
| | 479 | if (!i && !j) |
| | 480 | continue; |
| | 481 | |
| | 482 | dst[i] = decode_pixel_in_context(acoder, pctx, dst + i, stride, |
| | 483 | i, j, width - i - 1); |
| | 484 | } |
| | 485 | dst += stride; |
| | 486 | } |
| | 487 | |
| | 488 | return 0; |
| | 489 | } |
| | 490 | |
| | 491 | static int decode_region_masked(MSS1Context *ctx, ArithCoder *acoder, |
| | 492 | uint8_t *dst, int stride, uint8_t *mask, |
| | 493 | int mask_stride, int x, int y, |
| | 494 | int width, int height, |
| | 495 | PixContext *pctx) |
| | 496 | { |
| | 497 | int i, j; |
| | 498 | |
| | 499 | dst += x + y * stride; |
| | 500 | mask += x + y * mask_stride; |
| | 501 | |
| | 502 | if (mask[0] != 0xFF) |
| | 503 | dst[0] = decode_top_left_pixel(acoder, pctx); |
| | 504 | for (j = 0; j < height; j++) { |
| | 505 | for (i = 0; i < width; i++) { |
| | 506 | if (!i && !j || mask[i] != 0xFF) |
| | 507 | continue; |
| | 508 | |
| | 509 | dst[i] = decode_pixel_in_context(acoder, pctx, dst + i, stride, |
| | 510 | i, j, width - i - 1); |
| | 511 | } |
| | 512 | dst += stride; |
| | 513 | mask += mask_stride; |
| | 514 | } |
| | 515 | |
| | 516 | return 0; |
| | 517 | } |
| | 518 | |
| | 519 | static av_cold void codec_init(MSS1Context *ctx) |
| | 520 | { |
| | 521 | model_init(&ctx->intra_region, 2, THRESH_ADAPTIVE); |
| | 522 | model_init(&ctx->inter_region, 2, THRESH_ADAPTIVE); |
| | 523 | model_init(&ctx->split_mode, 3, THRESH_HIGH); |
| | 524 | model_init(&ctx->edge_mode, 2, THRESH_HIGH); |
| | 525 | model_init(&ctx->pivot, 3, THRESH_LOW); |
| | 526 | pixctx_init(&ctx->intra_pix_ctx, 8); |
| | 527 | pixctx_init(&ctx->inter_pix_ctx, 2); |
| | 528 | ctx->corrupted = 1; |
| | 529 | } |
| | 530 | |
| | 531 | static void codec_reset(MSS1Context *ctx) |
| | 532 | { |
| | 533 | model_reset(&ctx->intra_region); |
| | 534 | model_reset(&ctx->inter_region); |
| | 535 | model_reset(&ctx->split_mode); |
| | 536 | model_reset(&ctx->edge_mode); |
| | 537 | model_reset(&ctx->pivot); |
| | 538 | pixctx_reset(&ctx->intra_pix_ctx); |
| | 539 | pixctx_reset(&ctx->inter_pix_ctx); |
| | 540 | |
| | 541 | ctx->corrupted = 0; |
| | 542 | } |
| | 543 | |
| | 544 | static int decode_pal(MSS1Context *ctx, ArithCoder *acoder) |
| | 545 | { |
| | 546 | int i, ncol, r, g, b; |
| | 547 | uint32_t *pal = ctx->pal + 256 - ctx->free_colours; |
| | 548 | |
| | 549 | if (!ctx->free_colours) |
| | 550 | return 0; |
| | 551 | |
| | 552 | ncol = arith_get_number(acoder, ctx->free_colours + 1); |
| | 553 | for (i = 0; i < ncol; i++) { |
| | 554 | r = arith_get_bits(acoder, 8); |
| | 555 | g = arith_get_bits(acoder, 8); |
| | 556 | b = arith_get_bits(acoder, 8); |
| | 557 | *pal++ = (r << 16) | (g << 8) | b; |
| | 558 | } |
| | 559 | |
| | 560 | return 0; |
| | 561 | } |
| | 562 | |
| | 563 | static int decode_pivot(MSS1Context *ctx, ArithCoder *acoder, int base) |
| | 564 | { |
| | 565 | int val, inv; |
| | 566 | |
| | 567 | inv = arith_get_model_sym(acoder, &ctx->edge_mode); |
| | 568 | val = arith_get_model_sym(acoder, &ctx->pivot) + 1; |
| | 569 | |
| | 570 | if (val > 2) { |
| | 571 | if ((base + 1) / 2 - 2 <= 0) { |
| | 572 | ctx->corrupted = 1; |
| | 573 | return 0; |
| | 574 | } |
| | 575 | val = arith_get_number(acoder, (base + 1) / 2 - 2) + 3; |
| | 576 | } |
| | 577 | |
| | 578 | if (val == base) { |
| | 579 | ctx->corrupted = 1; |
| | 580 | return 0; |
| | 581 | } |
| | 582 | |
| | 583 | return inv ? base - val : val; |
| | 584 | } |
| | 585 | |
| | 586 | static int decode_region_intra(MSS1Context *ctx, ArithCoder *acoder, |
| | 587 | int x, int y, int width, int height) |
| | 588 | { |
| | 589 | int mode; |
| | 590 | |
| | 591 | mode = arith_get_model_sym(acoder, &ctx->intra_region); |
| | 592 | |
| | 593 | if (!mode) { |
| | 594 | int i, pix; |
| | 595 | int stride = ctx->pic_stride; |
| | 596 | uint8_t *dst = ctx->pic_start + x + y * stride; |
| | 597 | |
| | 598 | pix = decode_top_left_pixel(acoder, &ctx->intra_pix_ctx); |
| | 599 | for (i = 0; i < height; i++, dst += stride) |
| | 600 | memset(dst, pix, width); |
| | 601 | } else { |
| | 602 | return decode_region(ctx, acoder, ctx->pic_start, |
| | 603 | x, y, width, height, ctx->pic_stride, |
| | 604 | &ctx->intra_pix_ctx); |
| | 605 | } |
| | 606 | |
| | 607 | return 0; |
| | 608 | } |
| | 609 | |
| | 610 | static int decode_intra(MSS1Context *ctx, ArithCoder *acoder, |
| | 611 | int x, int y, int width, int height) |
| | 612 | { |
| | 613 | int mode, pivot; |
| | 614 | |
| | 615 | if (ctx->corrupted) |
| | 616 | return -1; |
| | 617 | |
| | 618 | mode = arith_get_model_sym(acoder, &ctx->split_mode); |
| | 619 | |
| | 620 | switch (mode) { |
| | 621 | case SPLIT_VERT: |
| | 622 | pivot = decode_pivot(ctx, acoder, height); |
| | 623 | if (ctx->corrupted) |
| | 624 | return -1; |
| | 625 | if (decode_intra(ctx, acoder, x, y, width, pivot)) |
| | 626 | return -1; |
| | 627 | if (decode_intra(ctx, acoder, x, y + pivot, width, height - pivot)) |
| | 628 | return -1; |
| | 629 | break; |
| | 630 | case SPLIT_HOR: |
| | 631 | pivot = decode_pivot(ctx, acoder, width); |
| | 632 | if (ctx->corrupted) |
| | 633 | return -1; |
| | 634 | if (decode_intra(ctx, acoder, x, y, pivot, height)) |
| | 635 | return -1; |
| | 636 | if (decode_intra(ctx, acoder, x + pivot, y, width - pivot, height)) |
| | 637 | return -1; |
| | 638 | break; |
| | 639 | case SPLIT_NONE: |
| | 640 | return decode_region_intra(ctx, acoder, x, y, width, height); |
| | 641 | default: |
| | 642 | return -1; |
| | 643 | } |
| | 644 | |
| | 645 | return 0; |
| | 646 | } |
| | 647 | |
| | 648 | static int decode_region_inter(MSS1Context *ctx, ArithCoder *acoder, |
| | 649 | int x, int y, int width, int height) |
| | 650 | { |
| | 651 | int mode; |
| | 652 | |
| | 653 | mode = arith_get_model_sym(acoder, &ctx->inter_region); |
| | 654 | |
| | 655 | if (!mode) { |
| | 656 | mode = decode_top_left_pixel(acoder, &ctx->inter_pix_ctx); |
| | 657 | if (mode != 0xFF) { |
| | 658 | return 0; |
| | 659 | } else { |
| | 660 | return decode_region_intra(ctx, acoder, x, y, width, height); |
| | 661 | } |
| | 662 | } else { |
| | 663 | if (decode_region(ctx, acoder, ctx->mask, |
| | 664 | x, y, width, height, ctx->mask_linesize, |
| | 665 | &ctx->inter_pix_ctx) < 0) |
| | 666 | return -1; |
| | 667 | return decode_region_masked(ctx, acoder, ctx->pic_start, |
| | 668 | -ctx->pic.linesize[0], ctx->mask, |
| | 669 | ctx->mask_linesize, |
| | 670 | x, y, width, height, |
| | 671 | &ctx->intra_pix_ctx); |
| | 672 | } |
| | 673 | |
| | 674 | return 0; |
| | 675 | } |
| | 676 | |
| | 677 | static int decode_inter(MSS1Context *ctx, ArithCoder *acoder, |
| | 678 | int x, int y, int width, int height) |
| | 679 | { |
| | 680 | int mode, pivot; |
| | 681 | |
| | 682 | if (ctx->corrupted) |
| | 683 | return -1; |
| | 684 | |
| | 685 | mode = arith_get_model_sym(acoder, &ctx->split_mode); |
| | 686 | |
| | 687 | switch (mode) { |
| | 688 | case SPLIT_VERT: |
| | 689 | pivot = decode_pivot(ctx, acoder, height); |
| | 690 | if (decode_inter(ctx, acoder, x, y, width, pivot)) |
| | 691 | return -1; |
| | 692 | if (decode_inter(ctx, acoder, x, y + pivot, width, height - pivot)) |
| | 693 | return -1; |
| | 694 | break; |
| | 695 | case SPLIT_HOR: |
| | 696 | pivot = decode_pivot(ctx, acoder, width); |
| | 697 | if (decode_inter(ctx, acoder, x, y, pivot, height)) |
| | 698 | return -1; |
| | 699 | if (decode_inter(ctx, acoder, x + pivot, y, width - pivot, height)) |
| | 700 | return -1; |
| | 701 | break; |
| | 702 | case SPLIT_NONE: |
| | 703 | return decode_region_inter(ctx, acoder, x, y, width, height); |
| | 704 | default: |
| | 705 | return -1; |
| | 706 | } |
| | 707 | |
| | 708 | return 0; |
| | 709 | } |
| | 710 | |
| | 711 | static int mss1_decode_frame(AVCodecContext *avctx, void *data, int *data_size, |
| | 712 | AVPacket *avpkt) |
| | 713 | { |
| | 714 | const uint8_t *buf = avpkt->data; |
| | 715 | int buf_size = avpkt->size; |
| | 716 | MSS1Context *c = avctx->priv_data; |
| | 717 | GetBitContext gb; |
| | 718 | ArithCoder acoder; |
| | 719 | int pal_changed = 0; |
| | 720 | int ret; |
| | 721 | |
| | 722 | init_get_bits(&gb, buf, buf_size * 8); |
| | 723 | arith_init(&acoder, &gb); |
| | 724 | |
| | 725 | c->pic.reference = 3; |
| | 726 | c->pic.buffer_hints = FF_BUFFER_HINTS_VALID | FF_BUFFER_HINTS_PRESERVE | |
| | 727 | FF_BUFFER_HINTS_REUSABLE; |
| | 728 | if ((ret = avctx->reget_buffer(avctx, &c->pic)) < 0) { |
| | 729 | av_log(avctx, AV_LOG_ERROR, "reget_buffer() failed\n"); |
| | 730 | return ret; |
| | 731 | } |
| | 732 | |
| | 733 | c->pic_start = c->pic.data[0] + c->pic.linesize[0] * (avctx->height - 1); |
| | 734 | c->pic_stride = -c->pic.linesize[0]; |
| | 735 | if (!arith_get_bit(&acoder)) { |
| | 736 | codec_reset(c); |
| | 737 | pal_changed = decode_pal(c, &acoder); |
| | 738 | c->corrupted = decode_intra(c, &acoder, 0, 0, |
| | 739 | avctx->width, avctx->height); |
| | 740 | c->pic.key_frame = 1; |
| | 741 | c->pic.pict_type = AV_PICTURE_TYPE_I; |
| | 742 | } else { |
| | 743 | if (c->corrupted) |
| | 744 | return AVERROR_INVALIDDATA; |
| | 745 | c->corrupted = decode_inter(c, &acoder, 0, 0, |
| | 746 | avctx->width, avctx->height); |
| | 747 | c->pic.key_frame = 0; |
| | 748 | c->pic.pict_type = AV_PICTURE_TYPE_P; |
| | 749 | } |
| | 750 | if (c->corrupted) |
| | 751 | return AVERROR_INVALIDDATA; |
| | 752 | memcpy(c->pic.data[1], c->pal, AVPALETTE_SIZE); |
| | 753 | c->pic.palette_has_changed = pal_changed; |
| | 754 | |
| | 755 | *data_size = sizeof(AVFrame); |
| | 756 | *(AVFrame*)data = c->pic; |
| | 757 | |
| | 758 | /* always report that the buffer was completely consumed */ |
| | 759 | return buf_size; |
| | 760 | } |
| | 761 | |
| | 762 | static av_cold int mss1_decode_init(AVCodecContext *avctx) |
| | 763 | { |
| | 764 | MSS1Context * const c = avctx->priv_data; |
| | 765 | int i; |
| | 766 | |
| | 767 | c->avctx = avctx; |
| | 768 | |
| | 769 | if (avctx->extradata_size < 52 + 256 * 3) { |
| | 770 | av_log(avctx, AV_LOG_ERROR, "Insufficient extradata size %d\n", |
| | 771 | avctx->extradata_size); |
| | 772 | return AVERROR_INVALIDDATA; |
| | 773 | } |
| | 774 | |
| | 775 | if (AV_RB32(avctx->extradata) < avctx->extradata_size) { |
| | 776 | av_log(avctx, AV_LOG_ERROR, |
| | 777 | "Insufficient extradata size: expected %d got %d\n", |
| | 778 | AV_RB32(avctx->extradata), |
| | 779 | avctx->extradata_size); |
| | 780 | return AVERROR_INVALIDDATA; |
| | 781 | } |
| | 782 | |
| | 783 | av_log(avctx, AV_LOG_DEBUG, "Encoder version %d.%d\n", |
| | 784 | AV_RB32(avctx->extradata + 4), AV_RB32(avctx->extradata + 8)); |
| | 785 | c->free_colours = AV_RB32(avctx->extradata + 48); |
| | 786 | av_log(avctx, AV_LOG_DEBUG, "%d free colour(s)\n", c->free_colours); |
| | 787 | avctx->coded_width = AV_RB32(avctx->extradata + 20); |
| | 788 | avctx->coded_height = AV_RB32(avctx->extradata + 24); |
| | 789 | |
| | 790 | av_log(avctx, AV_LOG_DEBUG, "Display dimensions %dx%d\n", |
| | 791 | AV_RB32(avctx->extradata + 12), AV_RB32(avctx->extradata + 16)); |
| | 792 | av_log(avctx, AV_LOG_DEBUG, "Coded dimensions %dx%d\n", |
| | 793 | avctx->coded_width, avctx->coded_height); |
| | 794 | av_log(avctx, AV_LOG_DEBUG, "%g frames per second\n", |
| | 795 | av_int2float(AV_RB32(avctx->extradata + 28))); |
| | 796 | av_log(avctx, AV_LOG_DEBUG, "Bitrate %d bps\n", |
| | 797 | AV_RB32(avctx->extradata + 32)); |
| | 798 | av_log(avctx, AV_LOG_DEBUG, "Max. lead time %g ms\n", |
| | 799 | av_int2float(AV_RB32(avctx->extradata + 36))); |
| | 800 | av_log(avctx, AV_LOG_DEBUG, "Max. lag time %g ms\n", |
| | 801 | av_int2float(AV_RB32(avctx->extradata + 40))); |
| | 802 | av_log(avctx, AV_LOG_DEBUG, "Max. seek time %g ms\n", |
| | 803 | av_int2float(AV_RB32(avctx->extradata + 44))); |
| | 804 | |
| | 805 | for (i = 0; i < 256; i++) |
| | 806 | c->pal[i] = AV_RB24(avctx->extradata + 52 + i * 3); |
| | 807 | |
| | 808 | avctx->pix_fmt = PIX_FMT_PAL8; |
| | 809 | |
| | 810 | c->mask_linesize = FFALIGN(avctx->width, 16); |
| | 811 | c->mask = av_malloc(c->mask_linesize * avctx->height); |
| | 812 | if (!c->mask) { |
| | 813 | av_log(avctx, AV_LOG_ERROR, "Cannot allocate mask plane\n"); |
| | 814 | return AVERROR(ENOMEM); |
| | 815 | } |
| | 816 | |
| | 817 | avctx->coded_frame = &c->pic; |
| | 818 | |
| | 819 | codec_init(c); |
| | 820 | |
| | 821 | return 0; |
| | 822 | } |
| | 823 | |
| | 824 | static av_cold int mss1_decode_end(AVCodecContext *avctx) |
| | 825 | { |
| | 826 | MSS1Context * const c = avctx->priv_data; |
| | 827 | |
| | 828 | if (c->pic.data[0]) |
| | 829 | avctx->release_buffer(avctx, &c->pic); |
| | 830 | av_freep(&c->mask); |
| | 831 | |
| | 832 | return 0; |
| | 833 | } |
| | 834 | |
| | 835 | AVCodec ff_mss1_decoder = { |
| | 836 | .name = "mss1", |
| | 837 | .type = AVMEDIA_TYPE_VIDEO, |
| | 838 | .id = CODEC_ID_MSS1, |
| | 839 | .priv_data_size = sizeof(MSS1Context), |
| | 840 | .init = mss1_decode_init, |
| | 841 | .close = mss1_decode_end, |
| | 842 | .decode = mss1_decode_frame, |
| | 843 | .capabilities = CODEC_CAP_DR1, |
| | 844 | .long_name = NULL_IF_CONFIG_SMALL("MS Screen 1"), |
| | 845 | }; |