1/* 2 * Wing Commander/Xan Video Decoder 3 * Copyright (C) 2011 Konstantin Shishkov 4 * based on work by Mike Melanson 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#include "libavutil/intreadwrite.h" 24#include "libavutil/mem.h" 25 26#include "avcodec.h" 27#include "bytestream.h" 28#include "codec_internal.h" 29#include "internal.h" 30 31typedef struct XanContext { 32 AVCodecContext *avctx; 33 AVFrame *pic; 34 35 uint8_t *y_buffer; 36 uint8_t *scratch_buffer; 37 int buffer_size; 38 GetByteContext gb; 39} XanContext; 40 41static av_cold int xan_decode_end(AVCodecContext *avctx) 42{ 43 XanContext *s = avctx->priv_data; 44 45 av_frame_free(&s->pic); 46 47 av_freep(&s->y_buffer); 48 av_freep(&s->scratch_buffer); 49 50 return 0; 51} 52 53static av_cold int xan_decode_init(AVCodecContext *avctx) 54{ 55 XanContext *s = avctx->priv_data; 56 57 s->avctx = avctx; 58 59 avctx->pix_fmt = AV_PIX_FMT_YUV420P; 60 61 if (avctx->height < 8) { 62 av_log(avctx, AV_LOG_ERROR, "Invalid frame height: %d.\n", avctx->height); 63 return AVERROR(EINVAL); 64 } 65 if (avctx->width & 1) { 66 av_log(avctx, AV_LOG_ERROR, "Invalid frame width: %d.\n", avctx->width); 67 return AVERROR(EINVAL); 68 } 69 70 s->buffer_size = avctx->width * avctx->height; 71 s->y_buffer = av_malloc(s->buffer_size); 72 if (!s->y_buffer) 73 return AVERROR(ENOMEM); 74 s->scratch_buffer = av_malloc(s->buffer_size + 130); 75 if (!s->scratch_buffer) 76 return AVERROR(ENOMEM); 77 78 s->pic = av_frame_alloc(); 79 if (!s->pic) 80 return AVERROR(ENOMEM); 81 82 return 0; 83} 84 85static int xan_unpack_luma(XanContext *s, 86 uint8_t *dst, const int dst_size) 87{ 88 int tree_size, eof; 89 int bits, mask; 90 int tree_root, node; 91 const uint8_t *dst_end = dst + dst_size; 92 GetByteContext tree = s->gb; 93 int start_off = bytestream2_tell(&tree); 94 95 tree_size = bytestream2_get_byte(&s->gb); 96 eof = bytestream2_get_byte(&s->gb); 97 tree_root = eof + tree_size; 98 bytestream2_skip(&s->gb, tree_size * 2); 99 100 node = tree_root; 101 bits = bytestream2_get_byte(&s->gb); 102 mask = 0x80; 103 for (;;) { 104 int bit = !!(bits & mask); 105 mask >>= 1; 106 bytestream2_seek(&tree, start_off + node*2 + bit - eof * 2, SEEK_SET); 107 node = bytestream2_get_byte(&tree); 108 if (node == eof) 109 break; 110 if (node < eof) { 111 *dst++ = node; 112 if (dst > dst_end) 113 break; 114 node = tree_root; 115 } 116 if (!mask) { 117 if (bytestream2_get_bytes_left(&s->gb) <= 0) 118 break; 119 bits = bytestream2_get_byteu(&s->gb); 120 mask = 0x80; 121 } 122 } 123 return dst != dst_end ? AVERROR_INVALIDDATA : 0; 124} 125 126/* almost the same as in xan_wc3 decoder */ 127static int xan_unpack(XanContext *s, 128 uint8_t *dest, const int dest_len) 129{ 130 uint8_t opcode; 131 int size; 132 uint8_t *orig_dest = dest; 133 const uint8_t *dest_end = dest + dest_len; 134 135 while (dest < dest_end) { 136 if (bytestream2_get_bytes_left(&s->gb) <= 0) 137 return AVERROR_INVALIDDATA; 138 139 opcode = bytestream2_get_byteu(&s->gb); 140 141 if (opcode < 0xe0) { 142 int size2, back; 143 if ((opcode & 0x80) == 0) { 144 size = opcode & 3; 145 back = ((opcode & 0x60) << 3) + bytestream2_get_byte(&s->gb) + 1; 146 size2 = ((opcode & 0x1c) >> 2) + 3; 147 } else if ((opcode & 0x40) == 0) { 148 size = bytestream2_peek_byte(&s->gb) >> 6; 149 back = (bytestream2_get_be16(&s->gb) & 0x3fff) + 1; 150 size2 = (opcode & 0x3f) + 4; 151 } else { 152 size = opcode & 3; 153 back = ((opcode & 0x10) << 12) + bytestream2_get_be16(&s->gb) + 1; 154 size2 = ((opcode & 0x0c) << 6) + bytestream2_get_byte(&s->gb) + 5; 155 if (size + size2 > dest_end - dest) 156 break; 157 } 158 if (dest + size + size2 > dest_end || 159 dest - orig_dest + size < back) 160 return AVERROR_INVALIDDATA; 161 bytestream2_get_buffer(&s->gb, dest, size); 162 dest += size; 163 av_memcpy_backptr(dest, back, size2); 164 dest += size2; 165 } else { 166 int finish = opcode >= 0xfc; 167 168 size = finish ? opcode & 3 : ((opcode & 0x1f) << 2) + 4; 169 if (dest_end - dest < size) 170 return AVERROR_INVALIDDATA; 171 bytestream2_get_buffer(&s->gb, dest, size); 172 dest += size; 173 if (finish) 174 break; 175 } 176 } 177 return dest - orig_dest; 178} 179 180static int xan_decode_chroma(AVCodecContext *avctx, unsigned chroma_off) 181{ 182 XanContext *s = avctx->priv_data; 183 uint8_t *U, *V; 184 int val, uval, vval; 185 int i, j; 186 const uint8_t *src, *src_end; 187 const uint8_t *table; 188 int mode, offset, dec_size, table_size; 189 190 if (!chroma_off) 191 return 0; 192 if (chroma_off + 4 >= bytestream2_get_bytes_left(&s->gb)) { 193 av_log(avctx, AV_LOG_ERROR, "Invalid chroma block position\n"); 194 return AVERROR_INVALIDDATA; 195 } 196 bytestream2_seek(&s->gb, chroma_off + 4, SEEK_SET); 197 mode = bytestream2_get_le16(&s->gb); 198 table = s->gb.buffer; 199 table_size = bytestream2_get_le16(&s->gb); 200 offset = table_size * 2; 201 table_size += 1; 202 203 if (offset >= bytestream2_get_bytes_left(&s->gb)) { 204 av_log(avctx, AV_LOG_ERROR, "Invalid chroma block offset\n"); 205 return AVERROR_INVALIDDATA; 206 } 207 208 bytestream2_skip(&s->gb, offset); 209 memset(s->scratch_buffer, 0, s->buffer_size); 210 dec_size = xan_unpack(s, s->scratch_buffer, s->buffer_size); 211 if (dec_size < 0) { 212 av_log(avctx, AV_LOG_ERROR, "Chroma unpacking failed\n"); 213 return dec_size; 214 } 215 216 U = s->pic->data[1]; 217 V = s->pic->data[2]; 218 src = s->scratch_buffer; 219 src_end = src + dec_size; 220 if (mode) { 221 for (j = 0; j < avctx->height >> 1; j++) { 222 for (i = 0; i < avctx->width >> 1; i++) { 223 if (src_end - src < 1) 224 return 0; 225 val = *src++; 226 if (val) { 227 if (val >= table_size) 228 return AVERROR_INVALIDDATA; 229 val = AV_RL16(table + (val << 1)); 230 uval = (val >> 3) & 0xF8; 231 vval = (val >> 8) & 0xF8; 232 U[i] = uval | (uval >> 5); 233 V[i] = vval | (vval >> 5); 234 } 235 } 236 U += s->pic->linesize[1]; 237 V += s->pic->linesize[2]; 238 } 239 if (avctx->height & 1) { 240 memcpy(U, U - s->pic->linesize[1], avctx->width >> 1); 241 memcpy(V, V - s->pic->linesize[2], avctx->width >> 1); 242 } 243 } else { 244 uint8_t *U2 = U + s->pic->linesize[1]; 245 uint8_t *V2 = V + s->pic->linesize[2]; 246 247 for (j = 0; j < avctx->height >> 2; j++) { 248 for (i = 0; i < avctx->width >> 1; i += 2) { 249 if (src_end - src < 1) 250 return 0; 251 val = *src++; 252 if (val) { 253 if (val >= table_size) 254 return AVERROR_INVALIDDATA; 255 val = AV_RL16(table + (val << 1)); 256 uval = (val >> 3) & 0xF8; 257 vval = (val >> 8) & 0xF8; 258 U[i] = U[i+1] = U2[i] = U2[i+1] = uval | (uval >> 5); 259 V[i] = V[i+1] = V2[i] = V2[i+1] = vval | (vval >> 5); 260 } 261 } 262 U += s->pic->linesize[1] * 2; 263 V += s->pic->linesize[2] * 2; 264 U2 += s->pic->linesize[1] * 2; 265 V2 += s->pic->linesize[2] * 2; 266 } 267 if (avctx->height & 3) { 268 int lines = ((avctx->height + 1) >> 1) - (avctx->height >> 2) * 2; 269 270 memcpy(U, U - lines * s->pic->linesize[1], lines * s->pic->linesize[1]); 271 memcpy(V, V - lines * s->pic->linesize[2], lines * s->pic->linesize[2]); 272 } 273 } 274 275 return 0; 276} 277 278static int xan_decode_frame_type0(AVCodecContext *avctx) 279{ 280 XanContext *s = avctx->priv_data; 281 uint8_t *ybuf, *prev_buf, *src = s->scratch_buffer; 282 unsigned chroma_off, corr_off; 283 int cur, last; 284 int i, j; 285 int ret; 286 287 chroma_off = bytestream2_get_le32(&s->gb); 288 corr_off = bytestream2_get_le32(&s->gb); 289 290 if ((ret = xan_decode_chroma(avctx, chroma_off)) != 0) 291 return ret; 292 293 if (corr_off >= bytestream2_size(&s->gb)) { 294 av_log(avctx, AV_LOG_WARNING, "Ignoring invalid correction block position\n"); 295 corr_off = 0; 296 } 297 bytestream2_seek(&s->gb, 12, SEEK_SET); 298 ret = xan_unpack_luma(s, src, s->buffer_size >> 1); 299 if (ret) { 300 av_log(avctx, AV_LOG_ERROR, "Luma decoding failed\n"); 301 return ret; 302 } 303 304 ybuf = s->y_buffer; 305 last = *src++; 306 ybuf[0] = last << 1; 307 for (j = 1; j < avctx->width - 1; j += 2) { 308 cur = (last + *src++) & 0x1F; 309 ybuf[j] = last + cur; 310 ybuf[j+1] = cur << 1; 311 last = cur; 312 } 313 ybuf[j] = last << 1; 314 prev_buf = ybuf; 315 ybuf += avctx->width; 316 317 for (i = 1; i < avctx->height; i++) { 318 last = ((prev_buf[0] >> 1) + *src++) & 0x1F; 319 ybuf[0] = last << 1; 320 for (j = 1; j < avctx->width - 1; j += 2) { 321 cur = ((prev_buf[j + 1] >> 1) + *src++) & 0x1F; 322 ybuf[j] = last + cur; 323 ybuf[j+1] = cur << 1; 324 last = cur; 325 } 326 ybuf[j] = last << 1; 327 prev_buf = ybuf; 328 ybuf += avctx->width; 329 } 330 331 if (corr_off) { 332 int dec_size; 333 334 bytestream2_seek(&s->gb, 8 + corr_off, SEEK_SET); 335 dec_size = xan_unpack(s, s->scratch_buffer, s->buffer_size / 2); 336 if (dec_size < 0) 337 dec_size = 0; 338 else 339 dec_size = FFMIN(dec_size, s->buffer_size/2 - 1); 340 341 for (i = 0; i < dec_size; i++) 342 s->y_buffer[i*2+1] = (s->y_buffer[i*2+1] + (s->scratch_buffer[i] << 1)) & 0x3F; 343 } 344 345 src = s->y_buffer; 346 ybuf = s->pic->data[0]; 347 for (j = 0; j < avctx->height; j++) { 348 for (i = 0; i < avctx->width; i++) 349 ybuf[i] = (src[i] << 2) | (src[i] >> 3); 350 src += avctx->width; 351 ybuf += s->pic->linesize[0]; 352 } 353 354 return 0; 355} 356 357static int xan_decode_frame_type1(AVCodecContext *avctx) 358{ 359 XanContext *s = avctx->priv_data; 360 uint8_t *ybuf, *src = s->scratch_buffer; 361 int cur, last; 362 int i, j; 363 int ret; 364 365 if ((ret = xan_decode_chroma(avctx, bytestream2_get_le32(&s->gb))) != 0) 366 return ret; 367 368 bytestream2_seek(&s->gb, 16, SEEK_SET); 369 ret = xan_unpack_luma(s, src, 370 s->buffer_size >> 1); 371 if (ret) { 372 av_log(avctx, AV_LOG_ERROR, "Luma decoding failed\n"); 373 return ret; 374 } 375 376 ybuf = s->y_buffer; 377 for (i = 0; i < avctx->height; i++) { 378 last = (ybuf[0] + (*src++ << 1)) & 0x3F; 379 ybuf[0] = last; 380 for (j = 1; j < avctx->width - 1; j += 2) { 381 cur = (ybuf[j + 1] + (*src++ << 1)) & 0x3F; 382 ybuf[j] = (last + cur) >> 1; 383 ybuf[j+1] = cur; 384 last = cur; 385 } 386 ybuf[j] = last; 387 ybuf += avctx->width; 388 } 389 390 src = s->y_buffer; 391 ybuf = s->pic->data[0]; 392 for (j = 0; j < avctx->height; j++) { 393 for (i = 0; i < avctx->width; i++) 394 ybuf[i] = (src[i] << 2) | (src[i] >> 3); 395 src += avctx->width; 396 ybuf += s->pic->linesize[0]; 397 } 398 399 return 0; 400} 401 402static int xan_decode_frame(AVCodecContext *avctx, AVFrame *rframe, 403 int *got_frame, AVPacket *avpkt) 404{ 405 XanContext *s = avctx->priv_data; 406 int ftype; 407 int ret; 408 409 if ((ret = ff_reget_buffer(avctx, s->pic, 0)) < 0) 410 return ret; 411 412 bytestream2_init(&s->gb, avpkt->data, avpkt->size); 413 ftype = bytestream2_get_le32(&s->gb); 414 switch (ftype) { 415 case 0: 416 ret = xan_decode_frame_type0(avctx); 417 break; 418 case 1: 419 ret = xan_decode_frame_type1(avctx); 420 break; 421 default: 422 av_log(avctx, AV_LOG_ERROR, "Unknown frame type %d\n", ftype); 423 return AVERROR_INVALIDDATA; 424 } 425 if (ret) 426 return ret; 427 428 if ((ret = av_frame_ref(rframe, s->pic)) < 0) 429 return ret; 430 431 *got_frame = 1; 432 433 return avpkt->size; 434} 435 436const FFCodec ff_xan_wc4_decoder = { 437 .p.name = "xan_wc4", 438 .p.long_name = NULL_IF_CONFIG_SMALL("Wing Commander IV / Xxan"), 439 .p.type = AVMEDIA_TYPE_VIDEO, 440 .p.id = AV_CODEC_ID_XAN_WC4, 441 .priv_data_size = sizeof(XanContext), 442 .init = xan_decode_init, 443 .close = xan_decode_end, 444 FF_CODEC_DECODE_CB(xan_decode_frame), 445 .p.capabilities = AV_CODEC_CAP_DR1, 446 .caps_internal = FF_CODEC_CAP_INIT_CLEANUP | FF_CODEC_CAP_INIT_THREADSAFE, 447}; 448