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 Libav. 7 * 8 * Libav 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 * Libav 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 Libav; if not, write to the Free Software 20 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA 21 */ 22 23#include "avcodec.h" 24#include "libavutil/intreadwrite.h" 25#include "bytestream.h" 26#define BITSTREAM_READER_LE 27#include "get_bits.h" 28// for av_memcpy_backptr 29#include "libavutil/lzo.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_init(AVCodecContext *avctx) 42{ 43 XanContext *s = avctx->priv_data; 44 45 s->avctx = avctx; 46 47 avctx->pix_fmt = PIX_FMT_YUV420P; 48 49 s->buffer_size = avctx->width * avctx->height; 50 s->y_buffer = av_malloc(s->buffer_size); 51 if (!s->y_buffer) 52 return AVERROR(ENOMEM); 53 s->scratch_buffer = av_malloc(s->buffer_size + 130); 54 if (!s->scratch_buffer) { 55 av_freep(&s->y_buffer); 56 return AVERROR(ENOMEM); 57 } 58 59 return 0; 60} 61 62static int xan_unpack_luma(XanContext *s, 63 uint8_t *dst, const int dst_size) 64{ 65 int tree_size, eof; 66 int bits, mask; 67 int tree_root, node; 68 const uint8_t *dst_end = dst + dst_size; 69 GetByteContext tree = s->gb; 70 int start_off = bytestream2_tell(&tree); 71 72 tree_size = bytestream2_get_byte(&s->gb); 73 eof = bytestream2_get_byte(&s->gb); 74 tree_root = eof + tree_size; 75 bytestream2_skip(&s->gb, tree_size * 2); 76 77 node = tree_root; 78 bits = bytestream2_get_byte(&s->gb); 79 mask = 0x80; 80 for (;;) { 81 int bit = !!(bits & mask); 82 mask >>= 1; 83 bytestream2_seek(&tree, start_off + node*2 + bit - eof * 2, SEEK_SET); 84 node = bytestream2_get_byte(&tree); 85 if (node == eof) 86 break; 87 if (node < eof) { 88 *dst++ = node; 89 if (dst > dst_end) 90 break; 91 node = tree_root; 92 } 93 if (!mask) { 94 if (bytestream2_get_bytes_left(&s->gb) <= 0) 95 break; 96 bits = bytestream2_get_byteu(&s->gb); 97 mask = 0x80; 98 } 99 } 100 return dst != dst_end ? AVERROR_INVALIDDATA : 0; 101} 102 103/* almost the same as in xan_wc3 decoder */ 104static int xan_unpack(XanContext *s, 105 uint8_t *dest, const int dest_len) 106{ 107 uint8_t opcode; 108 int size; 109 uint8_t *orig_dest = dest; 110 const uint8_t *dest_end = dest + dest_len; 111 112 while (dest < dest_end) { 113 if (bytestream2_get_bytes_left(&s->gb) <= 0) 114 return AVERROR_INVALIDDATA; 115 116 opcode = bytestream2_get_byteu(&s->gb); 117 118 if (opcode < 0xe0) { 119 int size2, back; 120 if ((opcode & 0x80) == 0) { 121 size = opcode & 3; 122 back = ((opcode & 0x60) << 3) + bytestream2_get_byte(&s->gb) + 1; 123 size2 = ((opcode & 0x1c) >> 2) + 3; 124 } else if ((opcode & 0x40) == 0) { 125 size = bytestream2_peek_byte(&s->gb) >> 6; 126 back = (bytestream2_get_be16(&s->gb) & 0x3fff) + 1; 127 size2 = (opcode & 0x3f) + 4; 128 } else { 129 size = opcode & 3; 130 back = ((opcode & 0x10) << 12) + bytestream2_get_be16(&s->gb) + 1; 131 size2 = ((opcode & 0x0c) << 6) + bytestream2_get_byte(&s->gb) + 5; 132 if (size + size2 > dest_end - dest) 133 break; 134 } 135 if (dest + size + size2 > dest_end || 136 dest - orig_dest + size < back) 137 return -1; 138 bytestream2_get_buffer(&s->gb, dest, size); 139 dest += size; 140 av_memcpy_backptr(dest, back, size2); 141 dest += size2; 142 } else { 143 int finish = opcode >= 0xfc; 144 145 size = finish ? opcode & 3 : ((opcode & 0x1f) << 2) + 4; 146 if (dest_end - dest < size) 147 return -1; 148 bytestream2_get_buffer(&s->gb, dest, size); 149 dest += size; 150 if (finish) 151 break; 152 } 153 } 154 return dest - orig_dest; 155} 156 157static int xan_decode_chroma(AVCodecContext *avctx, unsigned chroma_off) 158{ 159 XanContext *s = avctx->priv_data; 160 uint8_t *U, *V; 161 int val, uval, vval; 162 int i, j; 163 const uint8_t *src, *src_end; 164 const uint8_t *table; 165 int mode, offset, dec_size, table_size; 166 167 if (!chroma_off) 168 return 0; 169 if (chroma_off + 4 >= bytestream2_get_bytes_left(&s->gb)) { 170 av_log(avctx, AV_LOG_ERROR, "Invalid chroma block position\n"); 171 return -1; 172 } 173 bytestream2_seek(&s->gb, chroma_off + 4, SEEK_SET); 174 mode = bytestream2_get_le16(&s->gb); 175 table = s->gb.buffer; 176 table_size = bytestream2_get_le16(&s->gb); 177 offset = table_size * 2; 178 table_size += 1; 179 180 if (offset >= bytestream2_get_bytes_left(&s->gb)) { 181 av_log(avctx, AV_LOG_ERROR, "Invalid chroma block offset\n"); 182 return -1; 183 } 184 185 bytestream2_skip(&s->gb, offset); 186 memset(s->scratch_buffer, 0, s->buffer_size); 187 dec_size = xan_unpack(s, s->scratch_buffer, s->buffer_size); 188 if (dec_size < 0) { 189 av_log(avctx, AV_LOG_ERROR, "Chroma unpacking failed\n"); 190 return -1; 191 } 192 193 U = s->pic.data[1]; 194 V = s->pic.data[2]; 195 src = s->scratch_buffer; 196 src_end = src + dec_size; 197 if (mode) { 198 for (j = 0; j < avctx->height >> 1; j++) { 199 for (i = 0; i < avctx->width >> 1; i++) { 200 val = *src++; 201 if (val && val < table_size) { 202 val = AV_RL16(table + (val << 1)); 203 uval = (val >> 3) & 0xF8; 204 vval = (val >> 8) & 0xF8; 205 U[i] = uval | (uval >> 5); 206 V[i] = vval | (vval >> 5); 207 } 208 if (src == src_end) 209 return 0; 210 } 211 U += s->pic.linesize[1]; 212 V += s->pic.linesize[2]; 213 } 214 } else { 215 uint8_t *U2 = U + s->pic.linesize[1]; 216 uint8_t *V2 = V + s->pic.linesize[2]; 217 218 for (j = 0; j < avctx->height >> 2; j++) { 219 for (i = 0; i < avctx->width >> 1; i += 2) { 220 val = *src++; 221 if (val && val < table_size) { 222 val = AV_RL16(table + (val << 1)); 223 uval = (val >> 3) & 0xF8; 224 vval = (val >> 8) & 0xF8; 225 U[i] = U[i+1] = U2[i] = U2[i+1] = uval | (uval >> 5); 226 V[i] = V[i+1] = V2[i] = V2[i+1] = vval | (vval >> 5); 227 } 228 } 229 U += s->pic.linesize[1] * 2; 230 V += s->pic.linesize[2] * 2; 231 U2 += s->pic.linesize[1] * 2; 232 V2 += s->pic.linesize[2] * 2; 233 } 234 } 235 236 return 0; 237} 238 239static int xan_decode_frame_type0(AVCodecContext *avctx) 240{ 241 XanContext *s = avctx->priv_data; 242 uint8_t *ybuf, *prev_buf, *src = s->scratch_buffer; 243 unsigned chroma_off, corr_off; 244 int cur, last; 245 int i, j; 246 int ret; 247 248 chroma_off = bytestream2_get_le32(&s->gb); 249 corr_off = bytestream2_get_le32(&s->gb); 250 251 if ((ret = xan_decode_chroma(avctx, chroma_off)) != 0) 252 return ret; 253 254 if (corr_off >= (s->gb.buffer_end - s->gb.buffer_start)) { 255 av_log(avctx, AV_LOG_WARNING, "Ignoring invalid correction block position\n"); 256 corr_off = 0; 257 } 258 bytestream2_seek(&s->gb, 12, SEEK_SET); 259 ret = xan_unpack_luma(s, src, s->buffer_size >> 1); 260 if (ret) { 261 av_log(avctx, AV_LOG_ERROR, "Luma decoding failed\n"); 262 return ret; 263 } 264 265 ybuf = s->y_buffer; 266 last = *src++; 267 ybuf[0] = last << 1; 268 for (j = 1; j < avctx->width - 1; j += 2) { 269 cur = (last + *src++) & 0x1F; 270 ybuf[j] = last + cur; 271 ybuf[j+1] = cur << 1; 272 last = cur; 273 } 274 ybuf[j] = last << 1; 275 prev_buf = ybuf; 276 ybuf += avctx->width; 277 278 for (i = 1; i < avctx->height; i++) { 279 last = ((prev_buf[0] >> 1) + *src++) & 0x1F; 280 ybuf[0] = last << 1; 281 for (j = 1; j < avctx->width - 1; j += 2) { 282 cur = ((prev_buf[j + 1] >> 1) + *src++) & 0x1F; 283 ybuf[j] = last + cur; 284 ybuf[j+1] = cur << 1; 285 last = cur; 286 } 287 ybuf[j] = last << 1; 288 prev_buf = ybuf; 289 ybuf += avctx->width; 290 } 291 292 if (corr_off) { 293 int corr_end, dec_size; 294 295 corr_end = (s->gb.buffer_end - s->gb.buffer_start); 296 if (chroma_off > corr_off) 297 corr_end = chroma_off; 298 bytestream2_seek(&s->gb, 8 + corr_off, SEEK_SET); 299 dec_size = xan_unpack(s, s->scratch_buffer, s->buffer_size / 2); 300 if (dec_size < 0) 301 dec_size = 0; 302 for (i = 0; i < dec_size; i++) 303 s->y_buffer[i*2+1] = (s->y_buffer[i*2+1] + (s->scratch_buffer[i] << 1)) & 0x3F; 304 } 305 306 src = s->y_buffer; 307 ybuf = s->pic.data[0]; 308 for (j = 0; j < avctx->height; j++) { 309 for (i = 0; i < avctx->width; i++) 310 ybuf[i] = (src[i] << 2) | (src[i] >> 3); 311 src += avctx->width; 312 ybuf += s->pic.linesize[0]; 313 } 314 315 return 0; 316} 317 318static int xan_decode_frame_type1(AVCodecContext *avctx) 319{ 320 XanContext *s = avctx->priv_data; 321 uint8_t *ybuf, *src = s->scratch_buffer; 322 int cur, last; 323 int i, j; 324 int ret; 325 326 if ((ret = xan_decode_chroma(avctx, bytestream2_get_le32(&s->gb))) != 0) 327 return ret; 328 329 bytestream2_seek(&s->gb, 16, SEEK_SET); 330 ret = xan_unpack_luma(s, src, 331 s->buffer_size >> 1); 332 if (ret) { 333 av_log(avctx, AV_LOG_ERROR, "Luma decoding failed\n"); 334 return ret; 335 } 336 337 ybuf = s->y_buffer; 338 for (i = 0; i < avctx->height; i++) { 339 last = (ybuf[0] + (*src++ << 1)) & 0x3F; 340 ybuf[0] = last; 341 for (j = 1; j < avctx->width - 1; j += 2) { 342 cur = (ybuf[j + 1] + (*src++ << 1)) & 0x3F; 343 ybuf[j] = (last + cur) >> 1; 344 ybuf[j+1] = cur; 345 last = cur; 346 } 347 ybuf[j] = last; 348 ybuf += avctx->width; 349 } 350 351 src = s->y_buffer; 352 ybuf = s->pic.data[0]; 353 for (j = 0; j < avctx->height; j++) { 354 for (i = 0; i < avctx->width; i++) 355 ybuf[i] = (src[i] << 2) | (src[i] >> 3); 356 src += avctx->width; 357 ybuf += s->pic.linesize[0]; 358 } 359 360 return 0; 361} 362 363static int xan_decode_frame(AVCodecContext *avctx, 364 void *data, int *data_size, 365 AVPacket *avpkt) 366{ 367 XanContext *s = avctx->priv_data; 368 int ftype; 369 int ret; 370 371 s->pic.reference = 1; 372 s->pic.buffer_hints = FF_BUFFER_HINTS_VALID | 373 FF_BUFFER_HINTS_PRESERVE | 374 FF_BUFFER_HINTS_REUSABLE; 375 if ((ret = avctx->reget_buffer(avctx, &s->pic))) { 376 av_log(s->avctx, AV_LOG_ERROR, "reget_buffer() failed\n"); 377 return ret; 378 } 379 380 bytestream2_init(&s->gb, avpkt->data, avpkt->size); 381 ftype = bytestream2_get_le32(&s->gb); 382 switch (ftype) { 383 case 0: 384 ret = xan_decode_frame_type0(avctx); 385 break; 386 case 1: 387 ret = xan_decode_frame_type1(avctx); 388 break; 389 default: 390 av_log(avctx, AV_LOG_ERROR, "Unknown frame type %d\n", ftype); 391 return -1; 392 } 393 if (ret) 394 return ret; 395 396 *data_size = sizeof(AVFrame); 397 *(AVFrame*)data = s->pic; 398 399 return avpkt->size; 400} 401 402static av_cold int xan_decode_end(AVCodecContext *avctx) 403{ 404 XanContext *s = avctx->priv_data; 405 406 if (s->pic.data[0]) 407 avctx->release_buffer(avctx, &s->pic); 408 409 av_freep(&s->y_buffer); 410 av_freep(&s->scratch_buffer); 411 412 return 0; 413} 414 415AVCodec ff_xan_wc4_decoder = { 416 .name = "xan_wc4", 417 .type = AVMEDIA_TYPE_VIDEO, 418 .id = CODEC_ID_XAN_WC4, 419 .priv_data_size = sizeof(XanContext), 420 .init = xan_decode_init, 421 .close = xan_decode_end, 422 .decode = xan_decode_frame, 423 .capabilities = CODEC_CAP_DR1, 424 .long_name = NULL_IF_CONFIG_SMALL("Wing Commander IV / Xxan"), 425}; 426 427