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| 1 | +/* |
| 2 | + * CDToons video decoder |
| 3 | + * Copyright (C) 2020 Alyssa Milburn <amilburn@zall.org> |
| 4 | + * |
| 5 | + * This file is part of FFmpeg. |
| 6 | + * |
| 7 | + * FFmpeg 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 | + * FFmpeg 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 FFmpeg; 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 | + * CDToons video decoder |
| 25 | + * @author Alyssa Milburn <amilburn@zall.org> |
| 26 | + */ |
| 27 | + |
| 28 | +#include <stdint.h> |
| 29 | + |
| 30 | +#include "libavutil/attributes.h" |
| 31 | +#include "libavutil/internal.h" |
| 32 | +#include "avcodec.h" |
| 33 | +#include "bytestream.h" |
| 34 | +#include "internal.h" |
| 35 | + |
| 36 | +#define CDTOONS_HEADER_SIZE 44 |
| 37 | +#define CDTOONS_MAX_SPRITES 1200 |
| 38 | + |
| 39 | +typedef struct CDToonsSprite { |
| 40 | + uint16_t flags; |
| 41 | + uint16_t owner_frame; |
| 42 | + uint16_t start_frame; |
| 43 | + uint16_t end_frame; |
| 44 | + unsigned int alloc_size; |
| 45 | + uint32_t size; |
| 46 | + uint8_t *data; |
| 47 | + int active; |
| 48 | +} CDToonsSprite; |
| 49 | + |
| 50 | +typedef struct CDToonsContext { |
| 51 | + AVFrame *frame; |
| 52 | + |
| 53 | + uint16_t last_pal_id; ///< The index of the active palette sprite. |
| 54 | + uint32_t pal[256]; ///< The currently-used palette data. |
| 55 | + CDToonsSprite sprites[CDTOONS_MAX_SPRITES]; |
| 56 | +} CDToonsContext; |
| 57 | + |
| 58 | +static int cdtoons_render_sprite(AVCodecContext *avctx, const uint8_t *data, |
| 59 | + uint32_t data_size, |
| 60 | + int dst_x, int dst_y, int width, int height) |
| 61 | +{ |
| 62 | + CDToonsContext *c = avctx->priv_data; |
| 63 | + const uint8_t *next_line = data; |
| 64 | + const uint8_t *end = data + data_size;; |
| 65 | + uint16_t line_size; |
| 66 | + uint8_t *dest; |
| 67 | + int skip = 0, to_skip, x; |
| 68 | + |
| 69 | + if (dst_x + width > avctx->width) |
| 70 | + width = avctx->width - dst_x; |
| 71 | + if (dst_y + height > avctx->height) |
| 72 | + height = avctx->height - dst_y; |
| 73 | + |
| 74 | + if (dst_x < 0) { |
| 75 | + /* we need to skip the start of the scanlines */ |
| 76 | + skip = -dst_x; |
| 77 | + if (width <= skip) |
| 78 | + return 0; |
| 79 | + dst_x = 0; |
| 80 | + } |
| 81 | + |
| 82 | + for (int y = 0; y < height; y++) { |
| 83 | + /* one scanline at a time, size is provided */ |
| 84 | + data = next_line; |
| 85 | + if (data > end - 2) |
| 86 | + return 1; |
| 87 | + line_size = bytestream_get_be16(&data); |
| 88 | + next_line = data + line_size; |
| 89 | + if (dst_y + y < 0) |
| 90 | + continue; |
| 91 | + |
| 92 | + dest = c->frame->data[0] + (dst_y + y) * c->frame->linesize[0] + dst_x; |
| 93 | + |
| 94 | + to_skip = skip; |
| 95 | + x = 0; |
| 96 | + while (x < width - skip) { |
| 97 | + int raw, size; |
| 98 | + uint8_t val; |
| 99 | + |
| 100 | + if (data >= end) |
| 101 | + return 1; |
| 102 | + |
| 103 | + val = bytestream_get_byte(&data); |
| 104 | + raw = !(val & 0x80); |
| 105 | + size = (int)(val & 0x7F) + 1; |
| 106 | + |
| 107 | + /* skip the start of a scanline if it is off-screen */ |
| 108 | + if (to_skip >= size) { |
| 109 | + to_skip -= size; |
| 110 | + if (raw) { |
| 111 | + data += size; |
| 112 | + } else { |
| 113 | + data += 1; |
| 114 | + } |
| 115 | + if (data > next_line) |
| 116 | + return 1; |
| 117 | + continue; |
| 118 | + } else if (to_skip) { |
| 119 | + size -= to_skip; |
| 120 | + if (raw) |
| 121 | + data += to_skip; |
| 122 | + to_skip = 0; |
| 123 | + if (data > next_line) |
| 124 | + return 1; |
| 125 | + } |
| 126 | + |
| 127 | + if (x + size >= width - skip) |
| 128 | + size = width - skip - x; |
| 129 | + |
| 130 | + /* either raw data, or a run of a single color */ |
| 131 | + if (raw) { |
| 132 | + memcpy(dest + x, data, size); |
| 133 | + data += size; |
| 134 | + if (data > next_line) |
| 135 | + return 1; |
| 136 | + } else { |
| 137 | + uint8_t color = bytestream_get_byte(&data); |
| 138 | + /* ignore transparent runs */ |
| 139 | + if (color) |
| 140 | + memset(dest + x, color, size); |
| 141 | + } |
| 142 | + x += size; |
| 143 | + } |
| 144 | + } |
| 145 | + |
| 146 | + return 0; |
| 147 | +} |
| 148 | + |
| 149 | +static int cdtoons_decode_frame(AVCodecContext *avctx, void *data, |
| 150 | + int *got_frame, AVPacket *avpkt) |
| 151 | +{ |
| 152 | + CDToonsContext *c = avctx->priv_data; |
| 153 | + const uint8_t *buf = avpkt->data; |
| 154 | + const uint8_t *eod = avpkt->data + avpkt->size; |
| 155 | + const int buf_size = avpkt->size; |
| 156 | + uint16_t frame_id; |
| 157 | + uint8_t background_color; |
| 158 | + uint16_t sprite_count, sprite_offset; |
| 159 | + uint8_t referenced_count; |
| 160 | + uint16_t palette_id; |
| 161 | + uint8_t palette_set; |
| 162 | + int ret; |
| 163 | + int saw_embedded_sprites = 0; |
| 164 | + |
| 165 | + if (buf_size < CDTOONS_HEADER_SIZE) |
| 166 | + return AVERROR_INVALIDDATA; |
| 167 | + |
| 168 | + if ((ret = ff_reget_buffer(avctx, c->frame, 0)) < 0) |
| 169 | + return ret; |
| 170 | + |
| 171 | + /* a lot of the header is useless junk in the absence of |
| 172 | + * dirty rectangling etc */ |
| 173 | + buf += 2; /* version? (always 9?) */ |
| 174 | + frame_id = bytestream_get_be16(&buf); |
| 175 | + buf += 2; /* blocks_valid_until */ |
| 176 | + buf += 1; |
| 177 | + background_color = bytestream_get_byte(&buf); |
| 178 | + buf += 16; /* clip rect, dirty rect */ |
| 179 | + buf += 4; /* flags */ |
| 180 | + sprite_count = bytestream_get_be16(&buf); |
| 181 | + sprite_offset = bytestream_get_be16(&buf); |
| 182 | + buf += 2; /* max block id? */ |
| 183 | + referenced_count = bytestream_get_byte(&buf); |
| 184 | + buf += 1; |
| 185 | + palette_id = bytestream_get_be16(&buf); |
| 186 | + palette_set = bytestream_get_byte(&buf); |
| 187 | + buf += 5; |
| 188 | + |
| 189 | + /* read new sprites introduced in this frame */ |
| 190 | + buf = avpkt->data + sprite_offset; |
| 191 | + while (sprite_count--) { |
| 192 | + uint32_t size; |
| 193 | + uint16_t sprite_id; |
| 194 | + |
| 195 | + if (buf + 14 > eod) |
| 196 | + return AVERROR_INVALIDDATA; |
| 197 | + |
| 198 | + sprite_id = bytestream_get_be16(&buf); |
| 199 | + if (sprite_id >= CDTOONS_MAX_SPRITES) { |
| 200 | + av_log(avctx, AV_LOG_ERROR, |
| 201 | + "Sprite ID %d is too high.\n", sprite_id); |
| 202 | + return AVERROR_INVALIDDATA; |
| 203 | + } |
| 204 | + if (c->sprites[sprite_id].active) { |
| 205 | + av_log(avctx, AV_LOG_ERROR, |
| 206 | + "Sprite ID %d is a duplicate.\n", sprite_id); |
| 207 | + return AVERROR_INVALIDDATA; |
| 208 | + } |
| 209 | + |
| 210 | + c->sprites[sprite_id].flags = bytestream_get_be16(&buf); |
| 211 | + size = bytestream_get_be32(&buf); |
| 212 | + if (size < 14) { |
| 213 | + av_log(avctx, AV_LOG_ERROR, |
| 214 | + "Sprite only has %d bytes of data.\n", size); |
| 215 | + return AVERROR_INVALIDDATA; |
| 216 | + } |
| 217 | + size -= 14; |
| 218 | + c->sprites[sprite_id].size = size; |
| 219 | + c->sprites[sprite_id].owner_frame = frame_id; |
| 220 | + c->sprites[sprite_id].start_frame = bytestream_get_be16(&buf); |
| 221 | + c->sprites[sprite_id].end_frame = bytestream_get_be16(&buf); |
| 222 | + buf += 2; |
| 223 | + |
| 224 | + if (size > buf_size || buf + size > eod) |
| 225 | + return AVERROR_INVALIDDATA; |
| 226 | + |
| 227 | + av_fast_padded_malloc(&c->sprites[sprite_id].data, &c->sprites[sprite_id].alloc_size, size); |
| 228 | + if (!c->sprites[sprite_id].data) |
| 229 | + return AVERROR(ENOMEM); |
| 230 | + |
| 231 | + c->sprites[sprite_id].active = 1; |
| 232 | + |
| 233 | + bytestream_get_buffer(&buf, c->sprites[sprite_id].data, size); |
| 234 | + } |
| 235 | + |
| 236 | + /* render any embedded sprites */ |
| 237 | + while (buf < eod) { |
| 238 | + uint32_t tag, size; |
| 239 | + if (buf + 8 > eod) { |
| 240 | + av_log(avctx, AV_LOG_WARNING, "Ran (seriously) out of data for embedded sprites.\n"); |
| 241 | + return AVERROR_INVALIDDATA; |
| 242 | + } |
| 243 | + tag = bytestream_get_be32(&buf); |
| 244 | + size = bytestream_get_be32(&buf); |
| 245 | + if (tag == MKBETAG('D', 'i', 'f', 'f')) { |
| 246 | + uint16_t diff_count; |
| 247 | + if (buf + 10 > eod) { |
| 248 | + av_log(avctx, AV_LOG_WARNING, "Ran (seriously) out of data for Diff frame.\n"); |
| 249 | + return AVERROR_INVALIDDATA; |
| 250 | + } |
| 251 | + diff_count = bytestream_get_be16(&buf); |
| 252 | + buf += 8; /* clip rect? */ |
| 253 | + for (int i = 0; i < diff_count; i++) { |
| 254 | + int16_t top, left; |
| 255 | + uint16_t diff_size, width, height; |
| 256 | + |
| 257 | + if (buf + 16 > eod) { |
| 258 | + av_log(avctx, AV_LOG_WARNING, "Ran (seriously) out of data for Diff frame header.\n"); |
| 259 | + return AVERROR_INVALIDDATA; |
| 260 | + } |
| 261 | + |
| 262 | + top = bytestream_get_be16(&buf); |
| 263 | + left = bytestream_get_be16(&buf); |
| 264 | + buf += 4; /* bottom, right */ |
| 265 | + diff_size = bytestream_get_be32(&buf); |
| 266 | + width = bytestream_get_be16(&buf); |
| 267 | + height = bytestream_get_be16(&buf); |
| 268 | + if (diff_size < 4 || diff_size - 4 > eod - buf) { |
| 269 | + av_log(avctx, AV_LOG_WARNING, "Ran (seriously) out of data for Diff frame data.\n"); |
| 270 | + return AVERROR_INVALIDDATA; |
| 271 | + } |
| 272 | + if (cdtoons_render_sprite(avctx, buf + 4, diff_size - 8, |
| 273 | + left, top, width, height)) { |
| 274 | + av_log(avctx, AV_LOG_WARNING, "Ran beyond end of sprite while rendering.\n"); |
| 275 | + } |
| 276 | + buf += diff_size - 4; |
| 277 | + } |
| 278 | + saw_embedded_sprites = 1; |
| 279 | + } else { |
| 280 | + /* we don't care about any other entries */ |
| 281 | + if (size < 8 || size - 8 > eod - buf) { |
| 282 | + av_log(avctx, AV_LOG_WARNING, "Ran out of data for ignored entry (size %X, %d left).\n", size, (int)(eod - buf)); |
| 283 | + return AVERROR_INVALIDDATA; |
| 284 | + } |
| 285 | + buf += (size - 8); |
| 286 | + } |
| 287 | + } |
| 288 | + |
| 289 | + /* was an intra frame? */ |
| 290 | + if (saw_embedded_sprites) |
| 291 | + goto done; |
| 292 | + |
| 293 | + /* render any referenced sprites */ |
| 294 | + buf = avpkt->data + CDTOONS_HEADER_SIZE; |
| 295 | + eod = avpkt->data + sprite_offset; |
| 296 | + for (int i = 0; i < referenced_count; i++) { |
| 297 | + const uint8_t *block_data; |
| 298 | + uint16_t sprite_id, width, height; |
| 299 | + int16_t top, left, right; |
| 300 | + |
| 301 | + if (buf + 10 > eod) { |
| 302 | + av_log(avctx, AV_LOG_WARNING, "Ran (seriously) out of data when rendering.\n"); |
| 303 | + return AVERROR_INVALIDDATA; |
| 304 | + } |
| 305 | + |
| 306 | + sprite_id = bytestream_get_be16(&buf); |
| 307 | + top = bytestream_get_be16(&buf); |
| 308 | + left = bytestream_get_be16(&buf); |
| 309 | + buf += 2; /* bottom */ |
| 310 | + right = bytestream_get_be16(&buf); |
| 311 | + |
| 312 | + if ((i == 0) && (sprite_id == 0)) { |
| 313 | + /* clear background */ |
| 314 | + memset(c->frame->data[0], background_color, |
| 315 | + c->frame->linesize[0] * avctx->height); |
| 316 | + } |
| 317 | + |
| 318 | + if (!right) |
| 319 | + continue; |
| 320 | + if (sprite_id >= CDTOONS_MAX_SPRITES) { |
| 321 | + av_log(avctx, AV_LOG_ERROR, |
| 322 | + "Sprite ID %d is too high.\n", sprite_id); |
| 323 | + return AVERROR_INVALIDDATA; |
| 324 | + } |
| 325 | + |
| 326 | + block_data = c->sprites[sprite_id].data; |
| 327 | + if (!c->sprites[sprite_id].active) { |
| 328 | + /* this can happen when seeking around */ |
| 329 | + av_log(avctx, AV_LOG_WARNING, "Sprite %d is missing.\n", sprite_id); |
| 330 | + continue; |
| 331 | + } |
| 332 | + if (c->sprites[sprite_id].size < 14) { |
| 333 | + av_log(avctx, AV_LOG_ERROR, "Sprite %d is too small.\n", sprite_id); |
| 334 | + continue; |
| 335 | + } |
| 336 | + |
| 337 | + height = bytestream_get_be16(&block_data); |
| 338 | + width = bytestream_get_be16(&block_data); |
| 339 | + block_data += 10; |
| 340 | + if (cdtoons_render_sprite(avctx, block_data, |
| 341 | + c->sprites[sprite_id].size - 14, |
| 342 | + left, top, width, height)) { |
| 343 | + av_log(avctx, AV_LOG_WARNING, "Ran beyond end of sprite while rendering.\n"); |
| 344 | + } |
| 345 | + } |
| 346 | + |
| 347 | + if (palette_id && (palette_id != c->last_pal_id)) { |
| 348 | + if (palette_id >= CDTOONS_MAX_SPRITES) { |
| 349 | + av_log(avctx, AV_LOG_ERROR, |
| 350 | + "Palette ID %d is too high.\n", palette_id); |
| 351 | + return AVERROR_INVALIDDATA; |
| 352 | + } |
| 353 | + if (!c->sprites[palette_id].active) { |
| 354 | + /* this can happen when seeking around */ |
| 355 | + av_log(avctx, AV_LOG_WARNING, |
| 356 | + "Palette ID %d is missing.\n", palette_id); |
| 357 | + goto done; |
| 358 | + } |
| 359 | + if (c->sprites[palette_id].size != 256 * 2 * 3) { |
| 360 | + av_log(avctx, AV_LOG_ERROR, |
| 361 | + "Palette ID %d is wrong size (%d).\n", |
| 362 | + palette_id, c->sprites[palette_id].size); |
| 363 | + return AVERROR_INVALIDDATA; |
| 364 | + } |
| 365 | + c->last_pal_id = palette_id; |
| 366 | + if (!palette_set) { |
| 367 | + uint8_t *palette_data = c->sprites[palette_id].data; |
| 368 | + for (int i = 0; i < 256; i++) { |
| 369 | + /* QuickTime-ish palette: 16-bit RGB components */ |
| 370 | + unsigned r, g, b; |
| 371 | + r = *palette_data; |
| 372 | + g = *(palette_data + 2); |
| 373 | + b = *(palette_data + 4); |
| 374 | + c->pal[i] = (0xFFU << 24) | (r << 16) | (g << 8) | b; |
| 375 | + palette_data += 6; |
| 376 | + } |
| 377 | + /* first palette entry indicates transparency */ |
| 378 | + c->pal[0] = 0; |
| 379 | + c->frame->palette_has_changed = 1; |
| 380 | + } |
| 381 | + } |
| 382 | + |
| 383 | +done: |
| 384 | + /* discard outdated blocks */ |
| 385 | + for (int i = 0; i < CDTOONS_MAX_SPRITES; i++) { |
| 386 | + if (c->sprites[i].end_frame > frame_id) |
| 387 | + continue; |
| 388 | + c->sprites[i].active = 0; |
| 389 | + } |
| 390 | + |
| 391 | + memcpy(c->frame->data[1], c->pal, AVPALETTE_SIZE); |
| 392 | + |
| 393 | + if ((ret = av_frame_ref(data, c->frame)) < 0) |
| 394 | + return ret; |
| 395 | + |
| 396 | + *got_frame = 1; |
| 397 | + |
| 398 | + /* always report that the buffer was completely consumed */ |
| 399 | + return buf_size; |
| 400 | +} |
| 401 | + |
| 402 | +static av_cold int cdtoons_decode_init(AVCodecContext *avctx) |
| 403 | +{ |
| 404 | + CDToonsContext *c = avctx->priv_data; |
| 405 | + |
| 406 | + avctx->pix_fmt = AV_PIX_FMT_PAL8; |
| 407 | + c->last_pal_id = 0; |
| 408 | + c->frame = av_frame_alloc(); |
| 409 | + if (!c->frame) |
| 410 | + return AVERROR(ENOMEM); |
| 411 | + |
| 412 | + return 0; |
| 413 | +} |
| 414 | + |
| 415 | +static void cdtoons_flush(AVCodecContext *avctx) |
| 416 | +{ |
| 417 | + CDToonsContext *c = avctx->priv_data; |
| 418 | + |
| 419 | + c->last_pal_id = 0; |
| 420 | + for (int i = 0; i < CDTOONS_MAX_SPRITES; i++) |
| 421 | + c->sprites[i].active = 0; |
| 422 | +} |
| 423 | + |
| 424 | +static av_cold int cdtoons_decode_end(AVCodecContext *avctx) |
| 425 | +{ |
| 426 | + CDToonsContext *c = avctx->priv_data; |
| 427 | + |
| 428 | + for (int i = 0; i < CDTOONS_MAX_SPRITES; i++) { |
| 429 | + av_freep(&c->sprites[i].data); |
| 430 | + c->sprites[i].active = 0; |
| 431 | + } |
| 432 | + |
| 433 | + av_frame_free(&c->frame); |
| 434 | + |
| 435 | + return 0; |
| 436 | +} |
| 437 | + |
| 438 | +AVCodec ff_cdtoons_decoder = { |
| 439 | + .name = "cdtoons", |
| 440 | + .long_name = NULL_IF_CONFIG_SMALL("CDToons video"), |
| 441 | + .type = AVMEDIA_TYPE_VIDEO, |
| 442 | + .id = AV_CODEC_ID_CDTOONS, |
| 443 | + .priv_data_size = sizeof(CDToonsContext), |
| 444 | + .init = cdtoons_decode_init, |
| 445 | + .close = cdtoons_decode_end, |
| 446 | + .decode = cdtoons_decode_frame, |
| 447 | + .capabilities = AV_CODEC_CAP_DR1, |
| 448 | + .flush = cdtoons_flush, |
| 449 | +}; |