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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 | +}; |