1 /* 2 * Copyright 2010 Mozilla Foundation 3 * 4 * This program is made available under an ISC-style license. See the 5 * accompanying file LICENSE for details. 6 */ 7 #include <assert.h> 8 #include <stdlib.h> 9 #include <string.h> 10 11 #include "third_party/nestegg/halloc/halloc.h" 12 #include "third_party/nestegg/include/nestegg/nestegg.h" 13 14 /* EBML Elements */ 15 #define ID_EBML 0x1a45dfa3 16 #define ID_EBML_VERSION 0x4286 17 #define ID_EBML_READ_VERSION 0x42f7 18 #define ID_EBML_MAX_ID_LENGTH 0x42f2 19 #define ID_EBML_MAX_SIZE_LENGTH 0x42f3 20 #define ID_DOCTYPE 0x4282 21 #define ID_DOCTYPE_VERSION 0x4287 22 #define ID_DOCTYPE_READ_VERSION 0x4285 23 24 /* Global Elements */ 25 #define ID_VOID 0xec 26 #define ID_CRC32 0xbf 27 28 /* WebM Elements */ 29 #define ID_SEGMENT 0x18538067 30 31 /* Seek Head Elements */ 32 #define ID_SEEK_HEAD 0x114d9b74 33 #define ID_SEEK 0x4dbb 34 #define ID_SEEK_ID 0x53ab 35 #define ID_SEEK_POSITION 0x53ac 36 37 /* Info Elements */ 38 #define ID_INFO 0x1549a966 39 #define ID_TIMECODE_SCALE 0x2ad7b1 40 #define ID_DURATION 0x4489 41 42 /* Cluster Elements */ 43 #define ID_CLUSTER 0x1f43b675 44 #define ID_TIMECODE 0xe7 45 #define ID_BLOCK_GROUP 0xa0 46 #define ID_SIMPLE_BLOCK 0xa3 47 48 /* BlockGroup Elements */ 49 #define ID_BLOCK 0xa1 50 #define ID_BLOCK_DURATION 0x9b 51 #define ID_REFERENCE_BLOCK 0xfb 52 #define ID_DISCARD_PADDING 0x75a2 53 54 /* Tracks Elements */ 55 #define ID_TRACKS 0x1654ae6b 56 #define ID_TRACK_ENTRY 0xae 57 #define ID_TRACK_NUMBER 0xd7 58 #define ID_TRACK_UID 0x73c5 59 #define ID_TRACK_TYPE 0x83 60 #define ID_FLAG_ENABLED 0xb9 61 #define ID_FLAG_DEFAULT 0x88 62 #define ID_FLAG_LACING 0x9c 63 #define ID_TRACK_TIMECODE_SCALE 0x23314f 64 #define ID_LANGUAGE 0x22b59c 65 #define ID_CODEC_ID 0x86 66 #define ID_CODEC_PRIVATE 0x63a2 67 #define ID_CODEC_DELAY 0x56aa 68 #define ID_SEEK_PREROLL 0x56bb 69 70 /* Video Elements */ 71 #define ID_VIDEO 0xe0 72 #define ID_STEREO_MODE 0x53b8 73 #define ID_PIXEL_WIDTH 0xb0 74 #define ID_PIXEL_HEIGHT 0xba 75 #define ID_PIXEL_CROP_BOTTOM 0x54aa 76 #define ID_PIXEL_CROP_TOP 0x54bb 77 #define ID_PIXEL_CROP_LEFT 0x54cc 78 #define ID_PIXEL_CROP_RIGHT 0x54dd 79 #define ID_DISPLAY_WIDTH 0x54b0 80 #define ID_DISPLAY_HEIGHT 0x54ba 81 82 /* Audio Elements */ 83 #define ID_AUDIO 0xe1 84 #define ID_SAMPLING_FREQUENCY 0xb5 85 #define ID_CHANNELS 0x9f 86 #define ID_BIT_DEPTH 0x6264 87 88 /* Cues Elements */ 89 #define ID_CUES 0x1c53bb6b 90 #define ID_CUE_POINT 0xbb 91 #define ID_CUE_TIME 0xb3 92 #define ID_CUE_TRACK_POSITIONS 0xb7 93 #define ID_CUE_TRACK 0xf7 94 #define ID_CUE_CLUSTER_POSITION 0xf1 95 #define ID_CUE_BLOCK_NUMBER 0x5378 96 97 /* EBML Types */ 98 enum ebml_type_enum { 99 TYPE_UNKNOWN, 100 TYPE_MASTER, 101 TYPE_UINT, 102 TYPE_FLOAT, 103 TYPE_INT, 104 TYPE_STRING, 105 TYPE_BINARY 106 }; 107 108 #define LIMIT_STRING (1 << 20) 109 #define LIMIT_BINARY (1 << 24) 110 #define LIMIT_BLOCK (1 << 30) 111 #define LIMIT_FRAME (1 << 28) 112 113 /* Field Flags */ 114 #define DESC_FLAG_NONE 0 115 #define DESC_FLAG_MULTI (1 << 0) 116 #define DESC_FLAG_SUSPEND (1 << 1) 117 #define DESC_FLAG_OFFSET (1 << 2) 118 119 /* Block Header Flags */ 120 #define BLOCK_FLAGS_LACING 6 121 122 /* Lacing Constants */ 123 #define LACING_NONE 0 124 #define LACING_XIPH 1 125 #define LACING_FIXED 2 126 #define LACING_EBML 3 127 128 /* Track Types */ 129 #define TRACK_TYPE_VIDEO 1 130 #define TRACK_TYPE_AUDIO 2 131 132 /* Track IDs */ 133 #define TRACK_ID_VP8 "V_VP8" 134 #define TRACK_ID_VP9 "V_VP9" 135 #define TRACK_ID_VORBIS "A_VORBIS" 136 #define TRACK_ID_OPUS "A_OPUS" 137 138 enum vint_mask { 139 MASK_NONE, 140 MASK_FIRST_BIT 141 }; 142 143 struct ebml_binary { 144 unsigned char * data; 145 size_t length; 146 }; 147 148 struct ebml_list_node { 149 struct ebml_list_node * next; 150 uint64_t id; 151 void * data; 152 }; 153 154 struct ebml_list { 155 struct ebml_list_node * head; 156 struct ebml_list_node * tail; 157 }; 158 159 struct ebml_type { 160 union ebml_value { 161 uint64_t u; 162 double f; 163 int64_t i; 164 char * s; 165 struct ebml_binary b; 166 } v; 167 enum ebml_type_enum type; 168 int read; 169 }; 170 171 /* EBML Definitions */ 172 struct ebml { 173 struct ebml_type ebml_version; 174 struct ebml_type ebml_read_version; 175 struct ebml_type ebml_max_id_length; 176 struct ebml_type ebml_max_size_length; 177 struct ebml_type doctype; 178 struct ebml_type doctype_version; 179 struct ebml_type doctype_read_version; 180 }; 181 182 /* Matroksa Definitions */ 183 struct seek { 184 struct ebml_type id; 185 struct ebml_type position; 186 }; 187 188 struct seek_head { 189 struct ebml_list seek; 190 }; 191 192 struct info { 193 struct ebml_type timecode_scale; 194 struct ebml_type duration; 195 }; 196 197 struct block_group { 198 struct ebml_type duration; 199 struct ebml_type reference_block; 200 struct ebml_type discard_padding; 201 }; 202 203 struct cluster { 204 struct ebml_type timecode; 205 struct ebml_list block_group; 206 }; 207 208 struct video { 209 struct ebml_type stereo_mode; 210 struct ebml_type pixel_width; 211 struct ebml_type pixel_height; 212 struct ebml_type pixel_crop_bottom; 213 struct ebml_type pixel_crop_top; 214 struct ebml_type pixel_crop_left; 215 struct ebml_type pixel_crop_right; 216 struct ebml_type display_width; 217 struct ebml_type display_height; 218 }; 219 220 struct audio { 221 struct ebml_type sampling_frequency; 222 struct ebml_type channels; 223 struct ebml_type bit_depth; 224 }; 225 226 struct track_entry { 227 struct ebml_type number; 228 struct ebml_type uid; 229 struct ebml_type type; 230 struct ebml_type flag_enabled; 231 struct ebml_type flag_default; 232 struct ebml_type flag_lacing; 233 struct ebml_type track_timecode_scale; 234 struct ebml_type language; 235 struct ebml_type codec_id; 236 struct ebml_type codec_private; 237 struct ebml_type codec_delay; 238 struct ebml_type seek_preroll; 239 struct video video; 240 struct audio audio; 241 }; 242 243 struct tracks { 244 struct ebml_list track_entry; 245 }; 246 247 struct cue_track_positions { 248 struct ebml_type track; 249 struct ebml_type cluster_position; 250 struct ebml_type block_number; 251 }; 252 253 struct cue_point { 254 struct ebml_type time; 255 struct ebml_list cue_track_positions; 256 }; 257 258 struct cues { 259 struct ebml_list cue_point; 260 }; 261 262 struct segment { 263 struct ebml_list seek_head; 264 struct info info; 265 struct ebml_list cluster; 266 struct tracks tracks; 267 struct cues cues; 268 }; 269 270 /* Misc. */ 271 struct pool_ctx { 272 char dummy; 273 }; 274 275 struct list_node { 276 struct list_node * previous; 277 struct ebml_element_desc * node; 278 unsigned char * data; 279 }; 280 281 struct saved_state { 282 int64_t stream_offset; 283 struct list_node * ancestor; 284 uint64_t last_id; 285 uint64_t last_size; 286 int last_valid; 287 }; 288 289 struct frame { 290 unsigned char * data; 291 size_t length; 292 struct frame * next; 293 }; 294 295 /* Public (opaque) Structures */ 296 struct nestegg { 297 nestegg_io * io; 298 nestegg_log log; 299 struct pool_ctx * alloc_pool; 300 uint64_t last_id; 301 uint64_t last_size; 302 int last_valid; 303 struct list_node * ancestor; 304 struct ebml ebml; 305 struct segment segment; 306 int64_t segment_offset; 307 unsigned int track_count; 308 }; 309 310 struct nestegg_packet { 311 uint64_t track; 312 uint64_t timecode; 313 struct frame * frame; 314 int64_t discard_padding; 315 }; 316 317 /* Element Descriptor */ 318 struct ebml_element_desc { 319 char const * name; 320 uint64_t id; 321 enum ebml_type_enum type; 322 size_t offset; 323 unsigned int flags; 324 struct ebml_element_desc * children; 325 size_t size; 326 size_t data_offset; 327 }; 328 329 #define E_FIELD(ID, TYPE, STRUCT, FIELD) \ 330 { #ID, ID, TYPE, offsetof(STRUCT, FIELD), DESC_FLAG_NONE, NULL, 0, 0 } 331 #define E_MASTER(ID, TYPE, STRUCT, FIELD) \ 332 { #ID, ID, TYPE, offsetof(STRUCT, FIELD), DESC_FLAG_MULTI, ne_ ## FIELD ## _elements, \ 333 sizeof(struct FIELD), 0 } 334 #define E_SINGLE_MASTER_O(ID, TYPE, STRUCT, FIELD) \ 335 { #ID, ID, TYPE, offsetof(STRUCT, FIELD), DESC_FLAG_OFFSET, ne_ ## FIELD ## _elements, 0, \ 336 offsetof(STRUCT, FIELD ## _offset) } 337 #define E_SINGLE_MASTER(ID, TYPE, STRUCT, FIELD) \ 338 { #ID, ID, TYPE, offsetof(STRUCT, FIELD), DESC_FLAG_NONE, ne_ ## FIELD ## _elements, 0, 0 } 339 #define E_SUSPEND(ID, TYPE) \ 340 { #ID, ID, TYPE, 0, DESC_FLAG_SUSPEND, NULL, 0, 0 } 341 #define E_LAST \ 342 { NULL, 0, 0, 0, DESC_FLAG_NONE, NULL, 0, 0 } 343 344 /* EBML Element Lists */ 345 static struct ebml_element_desc ne_ebml_elements[] = { 346 E_FIELD(ID_EBML_VERSION, TYPE_UINT, struct ebml, ebml_version), 347 E_FIELD(ID_EBML_READ_VERSION, TYPE_UINT, struct ebml, ebml_read_version), 348 E_FIELD(ID_EBML_MAX_ID_LENGTH, TYPE_UINT, struct ebml, ebml_max_id_length), 349 E_FIELD(ID_EBML_MAX_SIZE_LENGTH, TYPE_UINT, struct ebml, ebml_max_size_length), 350 E_FIELD(ID_DOCTYPE, TYPE_STRING, struct ebml, doctype), 351 E_FIELD(ID_DOCTYPE_VERSION, TYPE_UINT, struct ebml, doctype_version), 352 E_FIELD(ID_DOCTYPE_READ_VERSION, TYPE_UINT, struct ebml, doctype_read_version), 353 E_LAST 354 }; 355 356 /* WebM Element Lists */ 357 static struct ebml_element_desc ne_seek_elements[] = { 358 E_FIELD(ID_SEEK_ID, TYPE_BINARY, struct seek, id), 359 E_FIELD(ID_SEEK_POSITION, TYPE_UINT, struct seek, position), 360 E_LAST 361 }; 362 363 static struct ebml_element_desc ne_seek_head_elements[] = { 364 E_MASTER(ID_SEEK, TYPE_MASTER, struct seek_head, seek), 365 E_LAST 366 }; 367 368 static struct ebml_element_desc ne_info_elements[] = { 369 E_FIELD(ID_TIMECODE_SCALE, TYPE_UINT, struct info, timecode_scale), 370 E_FIELD(ID_DURATION, TYPE_FLOAT, struct info, duration), 371 E_LAST 372 }; 373 374 static struct ebml_element_desc ne_block_group_elements[] = { 375 E_SUSPEND(ID_BLOCK, TYPE_BINARY), 376 E_FIELD(ID_BLOCK_DURATION, TYPE_UINT, struct block_group, duration), 377 E_FIELD(ID_REFERENCE_BLOCK, TYPE_INT, struct block_group, reference_block), 378 E_FIELD(ID_DISCARD_PADDING, TYPE_INT, struct block_group, discard_padding), 379 E_LAST 380 }; 381 382 static struct ebml_element_desc ne_cluster_elements[] = { 383 E_FIELD(ID_TIMECODE, TYPE_UINT, struct cluster, timecode), 384 E_MASTER(ID_BLOCK_GROUP, TYPE_MASTER, struct cluster, block_group), 385 E_SUSPEND(ID_SIMPLE_BLOCK, TYPE_BINARY), 386 E_LAST 387 }; 388 389 static struct ebml_element_desc ne_video_elements[] = { 390 E_FIELD(ID_STEREO_MODE, TYPE_UINT, struct video, stereo_mode), 391 E_FIELD(ID_PIXEL_WIDTH, TYPE_UINT, struct video, pixel_width), 392 E_FIELD(ID_PIXEL_HEIGHT, TYPE_UINT, struct video, pixel_height), 393 E_FIELD(ID_PIXEL_CROP_BOTTOM, TYPE_UINT, struct video, pixel_crop_bottom), 394 E_FIELD(ID_PIXEL_CROP_TOP, TYPE_UINT, struct video, pixel_crop_top), 395 E_FIELD(ID_PIXEL_CROP_LEFT, TYPE_UINT, struct video, pixel_crop_left), 396 E_FIELD(ID_PIXEL_CROP_RIGHT, TYPE_UINT, struct video, pixel_crop_right), 397 E_FIELD(ID_DISPLAY_WIDTH, TYPE_UINT, struct video, display_width), 398 E_FIELD(ID_DISPLAY_HEIGHT, TYPE_UINT, struct video, display_height), 399 E_LAST 400 }; 401 402 static struct ebml_element_desc ne_audio_elements[] = { 403 E_FIELD(ID_SAMPLING_FREQUENCY, TYPE_FLOAT, struct audio, sampling_frequency), 404 E_FIELD(ID_CHANNELS, TYPE_UINT, struct audio, channels), 405 E_FIELD(ID_BIT_DEPTH, TYPE_UINT, struct audio, bit_depth), 406 E_LAST 407 }; 408 409 static struct ebml_element_desc ne_track_entry_elements[] = { 410 E_FIELD(ID_TRACK_NUMBER, TYPE_UINT, struct track_entry, number), 411 E_FIELD(ID_TRACK_UID, TYPE_UINT, struct track_entry, uid), 412 E_FIELD(ID_TRACK_TYPE, TYPE_UINT, struct track_entry, type), 413 E_FIELD(ID_FLAG_ENABLED, TYPE_UINT, struct track_entry, flag_enabled), 414 E_FIELD(ID_FLAG_DEFAULT, TYPE_UINT, struct track_entry, flag_default), 415 E_FIELD(ID_FLAG_LACING, TYPE_UINT, struct track_entry, flag_lacing), 416 E_FIELD(ID_TRACK_TIMECODE_SCALE, TYPE_FLOAT, struct track_entry, track_timecode_scale), 417 E_FIELD(ID_LANGUAGE, TYPE_STRING, struct track_entry, language), 418 E_FIELD(ID_CODEC_ID, TYPE_STRING, struct track_entry, codec_id), 419 E_FIELD(ID_CODEC_PRIVATE, TYPE_BINARY, struct track_entry, codec_private), 420 E_FIELD(ID_CODEC_DELAY, TYPE_UINT, struct track_entry, codec_delay), 421 E_FIELD(ID_SEEK_PREROLL, TYPE_UINT, struct track_entry, seek_preroll), 422 E_SINGLE_MASTER(ID_VIDEO, TYPE_MASTER, struct track_entry, video), 423 E_SINGLE_MASTER(ID_AUDIO, TYPE_MASTER, struct track_entry, audio), 424 E_LAST 425 }; 426 427 static struct ebml_element_desc ne_tracks_elements[] = { 428 E_MASTER(ID_TRACK_ENTRY, TYPE_MASTER, struct tracks, track_entry), 429 E_LAST 430 }; 431 432 static struct ebml_element_desc ne_cue_track_positions_elements[] = { 433 E_FIELD(ID_CUE_TRACK, TYPE_UINT, struct cue_track_positions, track), 434 E_FIELD(ID_CUE_CLUSTER_POSITION, TYPE_UINT, struct cue_track_positions, cluster_position), 435 E_FIELD(ID_CUE_BLOCK_NUMBER, TYPE_UINT, struct cue_track_positions, block_number), 436 E_LAST 437 }; 438 439 static struct ebml_element_desc ne_cue_point_elements[] = { 440 E_FIELD(ID_CUE_TIME, TYPE_UINT, struct cue_point, time), 441 E_MASTER(ID_CUE_TRACK_POSITIONS, TYPE_MASTER, struct cue_point, cue_track_positions), 442 E_LAST 443 }; 444 445 static struct ebml_element_desc ne_cues_elements[] = { 446 E_MASTER(ID_CUE_POINT, TYPE_MASTER, struct cues, cue_point), 447 E_LAST 448 }; 449 450 static struct ebml_element_desc ne_segment_elements[] = { 451 E_MASTER(ID_SEEK_HEAD, TYPE_MASTER, struct segment, seek_head), 452 E_SINGLE_MASTER(ID_INFO, TYPE_MASTER, struct segment, info), 453 E_MASTER(ID_CLUSTER, TYPE_MASTER, struct segment, cluster), 454 E_SINGLE_MASTER(ID_TRACKS, TYPE_MASTER, struct segment, tracks), 455 E_SINGLE_MASTER(ID_CUES, TYPE_MASTER, struct segment, cues), 456 E_LAST 457 }; 458 459 static struct ebml_element_desc ne_top_level_elements[] = { 460 E_SINGLE_MASTER(ID_EBML, TYPE_MASTER, nestegg, ebml), 461 E_SINGLE_MASTER_O(ID_SEGMENT, TYPE_MASTER, nestegg, segment), 462 E_LAST 463 }; 464 465 #undef E_FIELD 466 #undef E_MASTER 467 #undef E_SINGLE_MASTER_O 468 #undef E_SINGLE_MASTER 469 #undef E_SUSPEND 470 #undef E_LAST 471 472 static struct pool_ctx * 473 ne_pool_init(void) 474 { 475 struct pool_ctx * pool; 476 477 pool = h_malloc(sizeof(*pool)); 478 if (!pool) 479 abort(); 480 return pool; 481 } 482 483 static void 484 ne_pool_destroy(struct pool_ctx * pool) 485 { 486 h_free(pool); 487 } 488 489 static void * 490 ne_pool_alloc(size_t size, struct pool_ctx * pool) 491 { 492 void * p; 493 494 p = h_malloc(size); 495 if (!p) 496 abort(); 497 hattach(p, pool); 498 memset(p, 0, size); 499 return p; 500 } 501 502 static void * 503 ne_alloc(size_t size) 504 { 505 void * p; 506 507 p = calloc(1, size); 508 if (!p) 509 abort(); 510 return p; 511 } 512 513 static int 514 ne_io_read(nestegg_io * io, void * buffer, size_t length) 515 { 516 return io->read(buffer, length, io->userdata); 517 } 518 519 static int 520 ne_io_seek(nestegg_io * io, int64_t offset, int whence) 521 { 522 return io->seek(offset, whence, io->userdata); 523 } 524 525 static int 526 ne_io_read_skip(nestegg_io * io, size_t length) 527 { 528 size_t get; 529 unsigned char buf[8192]; 530 int r = 1; 531 532 while (length > 0) { 533 get = length < sizeof(buf) ? length : sizeof(buf); 534 r = ne_io_read(io, buf, get); 535 if (r != 1) 536 break; 537 length -= get; 538 } 539 540 return r; 541 } 542 543 static int64_t 544 ne_io_tell(nestegg_io * io) 545 { 546 return io->tell(io->userdata); 547 } 548 549 static int 550 ne_bare_read_vint(nestegg_io * io, uint64_t * value, uint64_t * length, enum vint_mask maskflag) 551 { 552 int r; 553 unsigned char b; 554 size_t maxlen = 8; 555 unsigned int count = 1, mask = 1 << 7; 556 557 r = ne_io_read(io, &b, 1); 558 if (r != 1) 559 return r; 560 561 while (count < maxlen) { 562 if ((b & mask) != 0) 563 break; 564 mask >>= 1; 565 count += 1; 566 } 567 568 if (length) 569 *length = count; 570 *value = b; 571 572 if (maskflag == MASK_FIRST_BIT) 573 *value = b & ~mask; 574 575 while (--count) { 576 r = ne_io_read(io, &b, 1); 577 if (r != 1) 578 return r; 579 *value <<= 8; 580 *value |= b; 581 } 582 583 return 1; 584 } 585 586 static int 587 ne_read_id(nestegg_io * io, uint64_t * value, uint64_t * length) 588 { 589 return ne_bare_read_vint(io, value, length, MASK_NONE); 590 } 591 592 static int 593 ne_read_vint(nestegg_io * io, uint64_t * value, uint64_t * length) 594 { 595 return ne_bare_read_vint(io, value, length, MASK_FIRST_BIT); 596 } 597 598 static int 599 ne_read_svint(nestegg_io * io, int64_t * value, uint64_t * length) 600 { 601 int r; 602 uint64_t uvalue; 603 uint64_t ulength; 604 int64_t svint_subtr[] = { 605 0x3f, 0x1fff, 606 0xfffff, 0x7ffffff, 607 0x3ffffffffLL, 0x1ffffffffffLL, 608 0xffffffffffffLL, 0x7fffffffffffffLL 609 }; 610 611 r = ne_bare_read_vint(io, &uvalue, &ulength, MASK_FIRST_BIT); 612 if (r != 1) 613 return r; 614 *value = uvalue - svint_subtr[ulength - 1]; 615 if (length) 616 *length = ulength; 617 return r; 618 } 619 620 static int 621 ne_read_uint(nestegg_io * io, uint64_t * val, uint64_t length) 622 { 623 unsigned char b; 624 int r; 625 626 if (length == 0 || length > 8) 627 return -1; 628 r = ne_io_read(io, &b, 1); 629 if (r != 1) 630 return r; 631 *val = b; 632 while (--length) { 633 r = ne_io_read(io, &b, 1); 634 if (r != 1) 635 return r; 636 *val <<= 8; 637 *val |= b; 638 } 639 return 1; 640 } 641 642 static int 643 ne_read_int(nestegg_io * io, int64_t * val, uint64_t length) 644 { 645 int r; 646 uint64_t uval, base; 647 648 r = ne_read_uint(io, &uval, length); 649 if (r != 1) 650 return r; 651 652 if (length < sizeof(int64_t)) { 653 base = 1; 654 base <<= length * 8 - 1; 655 if (uval >= base) { 656 base = 1; 657 base <<= length * 8; 658 } else { 659 base = 0; 660 } 661 *val = uval - base; 662 } else { 663 *val = (int64_t) uval; 664 } 665 666 return 1; 667 } 668 669 static int 670 ne_read_float(nestegg_io * io, double * val, uint64_t length) 671 { 672 union { 673 uint64_t u; 674 float f; 675 double d; 676 } value; 677 int r; 678 679 /* Length == 10 not implemented. */ 680 if (length != 4 && length != 8) 681 return -1; 682 r = ne_read_uint(io, &value.u, length); 683 if (r != 1) 684 return r; 685 if (length == 4) 686 *val = value.f; 687 else 688 *val = value.d; 689 return 1; 690 } 691 692 static int 693 ne_read_string(nestegg * ctx, char ** val, uint64_t length) 694 { 695 char * str; 696 int r; 697 const size_t alloc_size = (size_t)length + 1; 698 699 if (length == 0 || length > LIMIT_STRING) 700 return -1; 701 str = ne_pool_alloc(alloc_size, ctx->alloc_pool); 702 r = ne_io_read(ctx->io, (unsigned char *) str, alloc_size - 1); 703 if (r != 1) 704 return r; 705 str[alloc_size - 1] = '\0'; 706 *val = str; 707 return 1; 708 } 709 710 static int 711 ne_read_binary(nestegg * ctx, struct ebml_binary * val, uint64_t length) 712 { 713 if (length == 0 || length > LIMIT_BINARY) 714 return -1; 715 val->length = (size_t)length; 716 val->data = ne_pool_alloc(val->length, ctx->alloc_pool); 717 return ne_io_read(ctx->io, val->data, val->length); 718 } 719 720 static int 721 ne_get_uint(struct ebml_type type, uint64_t * value) 722 { 723 if (!type.read) 724 return -1; 725 726 assert(type.type == TYPE_UINT); 727 728 *value = type.v.u; 729 730 return 0; 731 } 732 733 static int 734 ne_get_uint32(struct ebml_type type, unsigned int * value) 735 { 736 uint64_t v; 737 if (ne_get_uint(type, &v)) 738 return -1; 739 740 assert((unsigned int)v == v); 741 742 *value = (unsigned int)v; 743 744 return 0; 745 } 746 747 static int 748 ne_get_float(struct ebml_type type, double * value) 749 { 750 if (!type.read) 751 return -1; 752 753 assert(type.type == TYPE_FLOAT); 754 755 *value = type.v.f; 756 757 return 0; 758 } 759 760 static int 761 ne_get_string(struct ebml_type type, char ** value) 762 { 763 if (!type.read) 764 return -1; 765 766 assert(type.type == TYPE_STRING); 767 768 *value = type.v.s; 769 770 return 0; 771 } 772 773 static int 774 ne_get_binary(struct ebml_type type, struct ebml_binary * value) 775 { 776 if (!type.read) 777 return -1; 778 779 assert(type.type == TYPE_BINARY); 780 781 *value = type.v.b; 782 783 return 0; 784 } 785 786 static int 787 ne_is_ancestor_element(uint64_t id, struct list_node * ancestor) 788 { 789 struct ebml_element_desc * element; 790 791 for (; ancestor; ancestor = ancestor->previous) 792 for (element = ancestor->node; element->id; ++element) 793 if (element->id == id) 794 return 1; 795 796 return 0; 797 } 798 799 static struct ebml_element_desc * 800 ne_find_element(uint64_t id, struct ebml_element_desc * elements) 801 { 802 struct ebml_element_desc * element; 803 804 for (element = elements; element->id; ++element) 805 if (element->id == id) 806 return element; 807 808 return NULL; 809 } 810 811 static void 812 ne_ctx_push(nestegg * ctx, struct ebml_element_desc * ancestor, void * data) 813 { 814 struct list_node * item; 815 816 item = ne_alloc(sizeof(*item)); 817 item->previous = ctx->ancestor; 818 item->node = ancestor; 819 item->data = data; 820 ctx->ancestor = item; 821 } 822 823 static void 824 ne_ctx_pop(nestegg * ctx) 825 { 826 struct list_node * item; 827 828 item = ctx->ancestor; 829 ctx->ancestor = item->previous; 830 free(item); 831 } 832 833 static int 834 ne_ctx_save(nestegg * ctx, struct saved_state * s) 835 { 836 s->stream_offset = ne_io_tell(ctx->io); 837 if (s->stream_offset < 0) 838 return -1; 839 s->ancestor = ctx->ancestor; 840 s->last_id = ctx->last_id; 841 s->last_size = ctx->last_size; 842 s->last_valid = ctx->last_valid; 843 return 0; 844 } 845 846 static int 847 ne_ctx_restore(nestegg * ctx, struct saved_state * s) 848 { 849 int r; 850 851 r = ne_io_seek(ctx->io, s->stream_offset, NESTEGG_SEEK_SET); 852 if (r != 0) 853 return -1; 854 ctx->ancestor = s->ancestor; 855 ctx->last_id = s->last_id; 856 ctx->last_size = s->last_size; 857 ctx->last_valid = s->last_valid; 858 return 0; 859 } 860 861 static int 862 ne_peek_element(nestegg * ctx, uint64_t * id, uint64_t * size) 863 { 864 int r; 865 866 if (ctx->last_valid) { 867 if (id) 868 *id = ctx->last_id; 869 if (size) 870 *size = ctx->last_size; 871 return 1; 872 } 873 874 r = ne_read_id(ctx->io, &ctx->last_id, NULL); 875 if (r != 1) 876 return r; 877 878 r = ne_read_vint(ctx->io, &ctx->last_size, NULL); 879 if (r != 1) 880 return r; 881 882 if (id) 883 *id = ctx->last_id; 884 if (size) 885 *size = ctx->last_size; 886 887 ctx->last_valid = 1; 888 889 return 1; 890 } 891 892 static int 893 ne_read_element(nestegg * ctx, uint64_t * id, uint64_t * size) 894 { 895 int r; 896 897 r = ne_peek_element(ctx, id, size); 898 if (r != 1) 899 return r; 900 901 ctx->last_valid = 0; 902 903 return 1; 904 } 905 906 static void 907 ne_read_master(nestegg * ctx, struct ebml_element_desc * desc) 908 { 909 struct ebml_list * list; 910 struct ebml_list_node * node, * oldtail; 911 912 assert(desc->type == TYPE_MASTER && desc->flags & DESC_FLAG_MULTI); 913 914 ctx->log(ctx, NESTEGG_LOG_DEBUG, "multi master element %llx (%s)", 915 desc->id, desc->name); 916 917 list = (struct ebml_list *) (ctx->ancestor->data + desc->offset); 918 919 node = ne_pool_alloc(sizeof(*node), ctx->alloc_pool); 920 node->id = desc->id; 921 node->data = ne_pool_alloc(desc->size, ctx->alloc_pool); 922 923 oldtail = list->tail; 924 if (oldtail) 925 oldtail->next = node; 926 list->tail = node; 927 if (!list->head) 928 list->head = node; 929 930 ctx->log(ctx, NESTEGG_LOG_DEBUG, " -> using data %p", node->data); 931 932 ne_ctx_push(ctx, desc->children, node->data); 933 } 934 935 static void 936 ne_read_single_master(nestegg * ctx, struct ebml_element_desc * desc) 937 { 938 assert(desc->type == TYPE_MASTER && !(desc->flags & DESC_FLAG_MULTI)); 939 940 ctx->log(ctx, NESTEGG_LOG_DEBUG, "single master element %llx (%s)", 941 desc->id, desc->name); 942 ctx->log(ctx, NESTEGG_LOG_DEBUG, " -> using data %p (%u)", 943 ctx->ancestor->data + desc->offset, desc->offset); 944 945 ne_ctx_push(ctx, desc->children, ctx->ancestor->data + desc->offset); 946 } 947 948 static int 949 ne_read_simple(nestegg * ctx, struct ebml_element_desc * desc, size_t length) 950 { 951 struct ebml_type * storage; 952 int r = 0; 953 954 storage = (struct ebml_type *) (ctx->ancestor->data + desc->offset); 955 956 if (storage->read) { 957 ctx->log(ctx, NESTEGG_LOG_DEBUG, "element %llx (%s) already read, skipping", 958 desc->id, desc->name); 959 return 0; 960 } 961 962 storage->type = desc->type; 963 964 ctx->log(ctx, NESTEGG_LOG_DEBUG, "element %llx (%s) -> %p (%u)", 965 desc->id, desc->name, storage, desc->offset); 966 967 switch (desc->type) { 968 case TYPE_UINT: 969 r = ne_read_uint(ctx->io, &storage->v.u, length); 970 break; 971 case TYPE_FLOAT: 972 r = ne_read_float(ctx->io, &storage->v.f, length); 973 break; 974 case TYPE_INT: 975 r = ne_read_int(ctx->io, &storage->v.i, length); 976 break; 977 case TYPE_STRING: 978 r = ne_read_string(ctx, &storage->v.s, length); 979 break; 980 case TYPE_BINARY: 981 r = ne_read_binary(ctx, &storage->v.b, length); 982 break; 983 case TYPE_MASTER: 984 case TYPE_UNKNOWN: 985 assert(0); 986 break; 987 } 988 989 if (r == 1) 990 storage->read = 1; 991 992 return r; 993 } 994 995 static int 996 ne_parse(nestegg * ctx, struct ebml_element_desc * top_level, int64_t max_offset) 997 { 998 int r; 999 int64_t * data_offset; 1000 uint64_t id, size, peeked_id; 1001 struct ebml_element_desc * element; 1002 1003 if (!ctx->ancestor) 1004 return -1; 1005 1006 for (;;) { 1007 if (max_offset > 0 && ne_io_tell(ctx->io) >= max_offset) { 1008 /* Reached end of offset allowed for parsing - return gracefully */ 1009 r = 1; 1010 break; 1011 } 1012 r = ne_peek_element(ctx, &id, &size); 1013 if (r != 1) 1014 break; 1015 peeked_id = id; 1016 1017 element = ne_find_element(id, ctx->ancestor->node); 1018 if (element) { 1019 if (element->flags & DESC_FLAG_SUSPEND) { 1020 assert(element->type == TYPE_BINARY); 1021 ctx->log(ctx, NESTEGG_LOG_DEBUG, "suspend parse at %llx", id); 1022 r = 1; 1023 break; 1024 } 1025 1026 r = ne_read_element(ctx, &id, &size); 1027 if (r != 1) 1028 break; 1029 assert(id == peeked_id); 1030 1031 if (element->flags & DESC_FLAG_OFFSET) { 1032 data_offset = (int64_t *) (ctx->ancestor->data + element->data_offset); 1033 *data_offset = ne_io_tell(ctx->io); 1034 if (*data_offset < 0) { 1035 r = -1; 1036 break; 1037 } 1038 } 1039 1040 if (element->type == TYPE_MASTER) { 1041 if (element->flags & DESC_FLAG_MULTI) 1042 ne_read_master(ctx, element); 1043 else 1044 ne_read_single_master(ctx, element); 1045 continue; 1046 } else { 1047 r = ne_read_simple(ctx, element, (size_t)size); 1048 if (r < 0) 1049 break; 1050 } 1051 } else if (ne_is_ancestor_element(id, ctx->ancestor->previous)) { 1052 ctx->log(ctx, NESTEGG_LOG_DEBUG, "parent element %llx", id); 1053 if (top_level && ctx->ancestor->node == top_level) { 1054 ctx->log(ctx, NESTEGG_LOG_DEBUG, "*** parse about to back up past top_level"); 1055 r = 1; 1056 break; 1057 } 1058 ne_ctx_pop(ctx); 1059 } else { 1060 r = ne_read_element(ctx, &id, &size); 1061 if (r != 1) 1062 break; 1063 1064 if (id != ID_VOID && id != ID_CRC32) 1065 ctx->log(ctx, NESTEGG_LOG_DEBUG, "unknown element %llx", id); 1066 r = ne_io_read_skip(ctx->io, (size_t)size); 1067 if (r != 1) 1068 break; 1069 } 1070 } 1071 1072 if (r != 1) 1073 while (ctx->ancestor) 1074 ne_ctx_pop(ctx); 1075 1076 return r; 1077 } 1078 1079 static uint64_t 1080 ne_xiph_lace_value(unsigned char ** np) 1081 { 1082 uint64_t lace; 1083 uint64_t value; 1084 unsigned char * p = *np; 1085 1086 lace = *p++; 1087 value = lace; 1088 while (lace == 255) { 1089 lace = *p++; 1090 value += lace; 1091 } 1092 1093 *np = p; 1094 1095 return value; 1096 } 1097 1098 static int 1099 ne_read_xiph_lace_value(nestegg_io * io, uint64_t * value, size_t * consumed) 1100 { 1101 int r; 1102 uint64_t lace; 1103 1104 r = ne_read_uint(io, &lace, 1); 1105 if (r != 1) 1106 return r; 1107 *consumed += 1; 1108 1109 *value = lace; 1110 while (lace == 255) { 1111 r = ne_read_uint(io, &lace, 1); 1112 if (r != 1) 1113 return r; 1114 *consumed += 1; 1115 *value += lace; 1116 } 1117 1118 return 1; 1119 } 1120 1121 static int 1122 ne_read_xiph_lacing(nestegg_io * io, size_t block, size_t * read, uint64_t n, uint64_t * sizes) 1123 { 1124 int r; 1125 size_t i = 0; 1126 uint64_t sum = 0; 1127 1128 while (--n) { 1129 r = ne_read_xiph_lace_value(io, &sizes[i], read); 1130 if (r != 1) 1131 return r; 1132 sum += sizes[i]; 1133 i += 1; 1134 } 1135 1136 if (*read + sum > block) 1137 return -1; 1138 1139 /* Last frame is the remainder of the block. */ 1140 sizes[i] = block - *read - sum; 1141 return 1; 1142 } 1143 1144 static int 1145 ne_read_ebml_lacing(nestegg_io * io, size_t block, size_t * read, uint64_t n, uint64_t * sizes) 1146 { 1147 int r; 1148 uint64_t lace, sum, length; 1149 int64_t slace; 1150 size_t i = 0; 1151 1152 r = ne_read_vint(io, &lace, &length); 1153 if (r != 1) 1154 return r; 1155 assert(length <= 8); 1156 *read += (size_t)length; 1157 1158 sizes[i] = lace; 1159 sum = sizes[i]; 1160 1161 i += 1; 1162 n -= 1; 1163 1164 while (--n) { 1165 r = ne_read_svint(io, &slace, &length); 1166 if (r != 1) 1167 return r; 1168 assert(length <= 8); 1169 *read += (size_t)length; 1170 sizes[i] = sizes[i - 1] + slace; 1171 sum += sizes[i]; 1172 i += 1; 1173 } 1174 1175 if (*read + sum > block) 1176 return -1; 1177 1178 /* Last frame is the remainder of the block. */ 1179 sizes[i] = block - *read - sum; 1180 return 1; 1181 } 1182 1183 static uint64_t 1184 ne_get_timecode_scale(nestegg * ctx) 1185 { 1186 uint64_t scale; 1187 1188 if (ne_get_uint(ctx->segment.info.timecode_scale, &scale) != 0) 1189 scale = 1000000; 1190 1191 return scale; 1192 } 1193 1194 static int 1195 ne_map_track_number_to_index(nestegg * ctx, 1196 unsigned int track_number, 1197 unsigned int * track_index) 1198 { 1199 struct ebml_list_node * node; 1200 struct track_entry * t_entry; 1201 uint64_t t_number = 0; 1202 1203 if (!track_index) 1204 return -1; 1205 *track_index = 0; 1206 1207 if (track_number == 0) 1208 return -1; 1209 1210 node = ctx->segment.tracks.track_entry.head; 1211 while (node) { 1212 assert(node->id == ID_TRACK_ENTRY); 1213 t_entry = node->data; 1214 if (ne_get_uint(t_entry->number, &t_number) != 0) 1215 return -1; 1216 if (t_number == track_number) 1217 return 0; 1218 *track_index += 1; 1219 node = node->next; 1220 } 1221 1222 return -1; 1223 } 1224 1225 static struct track_entry * 1226 ne_find_track_entry(nestegg * ctx, unsigned int track) 1227 { 1228 struct ebml_list_node * node; 1229 unsigned int tracks = 0; 1230 1231 node = ctx->segment.tracks.track_entry.head; 1232 while (node) { 1233 assert(node->id == ID_TRACK_ENTRY); 1234 if (track == tracks) 1235 return node->data; 1236 tracks += 1; 1237 node = node->next; 1238 } 1239 1240 return NULL; 1241 } 1242 1243 static int 1244 ne_read_block(nestegg * ctx, uint64_t block_id, uint64_t block_size, nestegg_packet ** data) 1245 { 1246 int r; 1247 int64_t timecode, abs_timecode; 1248 nestegg_packet * pkt; 1249 struct cluster * cluster; 1250 struct frame * f, * last; 1251 struct track_entry * entry; 1252 const int track_scale = 1; 1253 uint64_t track_number, length, frame_sizes[256], cluster_tc, flags, frames, tc_scale, total; 1254 unsigned int i, lacing, track; 1255 size_t consumed = 0; 1256 1257 *data = NULL; 1258 1259 if (block_size > LIMIT_BLOCK) 1260 return -1; 1261 1262 r = ne_read_vint(ctx->io, &track_number, &length); 1263 if (r != 1) 1264 return r; 1265 1266 if (track_number == 0 || (unsigned int)track_number != track_number) 1267 return -1; 1268 1269 assert(length <= 8); 1270 consumed += (size_t)length; 1271 1272 r = ne_read_int(ctx->io, &timecode, 2); 1273 if (r != 1) 1274 return r; 1275 1276 consumed += 2; 1277 1278 r = ne_read_uint(ctx->io, &flags, 1); 1279 if (r != 1) 1280 return r; 1281 1282 consumed += 1; 1283 1284 frames = 0; 1285 1286 /* Flags are different between Block and SimpleBlock, but lacing is 1287 encoded the same way. */ 1288 lacing = (flags & BLOCK_FLAGS_LACING) >> 1; 1289 1290 switch (lacing) { 1291 case LACING_NONE: 1292 frames = 1; 1293 break; 1294 case LACING_XIPH: 1295 case LACING_FIXED: 1296 case LACING_EBML: 1297 r = ne_read_uint(ctx->io, &frames, 1); 1298 if (r != 1) 1299 return r; 1300 consumed += 1; 1301 frames += 1; 1302 } 1303 1304 if (frames > 256) 1305 return -1; 1306 1307 switch (lacing) { 1308 case LACING_NONE: 1309 frame_sizes[0] = block_size - consumed; 1310 break; 1311 case LACING_XIPH: 1312 if (frames == 1) 1313 return -1; 1314 r = ne_read_xiph_lacing(ctx->io, (size_t)block_size, &consumed, frames, frame_sizes); 1315 if (r != 1) 1316 return r; 1317 break; 1318 case LACING_FIXED: 1319 if ((block_size - consumed) % frames) 1320 return -1; 1321 for (i = 0; i < frames; ++i) 1322 frame_sizes[i] = (block_size - consumed) / frames; 1323 break; 1324 case LACING_EBML: 1325 if (frames == 1) 1326 return -1; 1327 r = ne_read_ebml_lacing(ctx->io, (size_t)block_size, &consumed, frames, frame_sizes); 1328 if (r != 1) 1329 return r; 1330 break; 1331 } 1332 1333 /* Sanity check unlaced frame sizes against total block size. */ 1334 total = consumed; 1335 for (i = 0; i < frames; ++i) 1336 total += frame_sizes[i]; 1337 if (total > block_size) 1338 return -1; 1339 1340 if (ne_map_track_number_to_index(ctx, (unsigned int)track_number, &track) != 0) 1341 return -1; 1342 1343 entry = ne_find_track_entry(ctx, track); 1344 if (!entry) 1345 return -1; 1346 1347 tc_scale = ne_get_timecode_scale(ctx); 1348 1349 assert(ctx->segment.cluster.tail->id == ID_CLUSTER); 1350 cluster = ctx->segment.cluster.tail->data; 1351 if (ne_get_uint(cluster->timecode, &cluster_tc) != 0) 1352 return -1; 1353 1354 abs_timecode = timecode + cluster_tc; 1355 if (abs_timecode < 0) 1356 return -1; 1357 1358 pkt = ne_alloc(sizeof(*pkt)); 1359 pkt->track = track; 1360 pkt->timecode = abs_timecode * tc_scale * track_scale; 1361 1362 ctx->log(ctx, NESTEGG_LOG_DEBUG, "%sblock t %lld pts %f f %llx frames: %llu", 1363 block_id == ID_BLOCK ? "" : "simple", pkt->track, pkt->timecode / 1e9, flags, frames); 1364 1365 last = NULL; 1366 for (i = 0; i < frames; ++i) { 1367 if (frame_sizes[i] > LIMIT_FRAME) { 1368 nestegg_free_packet(pkt); 1369 return -1; 1370 } 1371 f = ne_alloc(sizeof(*f)); 1372 f->length = (size_t)frame_sizes[i]; 1373 f->data = ne_alloc(f->length); 1374 r = ne_io_read(ctx->io, f->data, f->length); 1375 if (r != 1) { 1376 free(f->data); 1377 free(f); 1378 nestegg_free_packet(pkt); 1379 return -1; 1380 } 1381 1382 if (!last) 1383 pkt->frame = f; 1384 else 1385 last->next = f; 1386 last = f; 1387 } 1388 1389 *data = pkt; 1390 1391 return 1; 1392 } 1393 1394 static int 1395 ne_read_discard_padding(nestegg * ctx, nestegg_packet * pkt) 1396 { 1397 int r; 1398 uint64_t id, size; 1399 struct ebml_element_desc * element; 1400 struct ebml_type * storage; 1401 1402 r = ne_peek_element(ctx, &id, &size); 1403 if (r != 1) 1404 return r; 1405 1406 if (id != ID_DISCARD_PADDING) 1407 return 1; 1408 1409 element = ne_find_element(id, ctx->ancestor->node); 1410 if (!element) 1411 return 1; 1412 1413 assert((size_t)size == size); 1414 r = ne_read_simple(ctx, element, (size_t)size); 1415 if (r != 1) 1416 return r; 1417 storage = (struct ebml_type *) (ctx->ancestor->data + element->offset); 1418 pkt->discard_padding = storage->v.i; 1419 1420 return 1; 1421 } 1422 1423 1424 static uint64_t 1425 ne_buf_read_id(unsigned char const * p, size_t length) 1426 { 1427 uint64_t id = 0; 1428 1429 while (length--) { 1430 id <<= 8; 1431 id |= *p++; 1432 } 1433 1434 return id; 1435 } 1436 1437 static struct seek * 1438 ne_find_seek_for_id(struct ebml_list_node * seek_head, uint64_t id) 1439 { 1440 struct ebml_list * head; 1441 struct ebml_list_node * seek; 1442 struct ebml_binary binary_id; 1443 struct seek * s; 1444 1445 while (seek_head) { 1446 assert(seek_head->id == ID_SEEK_HEAD); 1447 head = seek_head->data; 1448 seek = head->head; 1449 1450 while (seek) { 1451 assert(seek->id == ID_SEEK); 1452 s = seek->data; 1453 1454 if (ne_get_binary(s->id, &binary_id) == 0 && 1455 ne_buf_read_id(binary_id.data, binary_id.length) == id) 1456 return s; 1457 1458 seek = seek->next; 1459 } 1460 1461 seek_head = seek_head->next; 1462 } 1463 1464 return NULL; 1465 } 1466 1467 static struct cue_track_positions * 1468 ne_find_cue_position_for_track(nestegg * ctx, struct ebml_list_node * node, unsigned int track) 1469 { 1470 struct cue_track_positions * pos = NULL; 1471 unsigned int track_number; 1472 unsigned int t; 1473 1474 while (node) { 1475 assert(node->id == ID_CUE_TRACK_POSITIONS); 1476 pos = node->data; 1477 if (ne_get_uint32(pos->track, &track_number) != 0) 1478 return NULL; 1479 1480 if (ne_map_track_number_to_index(ctx, track_number, &t) != 0) 1481 return NULL; 1482 1483 if (t == track) 1484 return pos; 1485 1486 node = node->next; 1487 } 1488 1489 return NULL; 1490 } 1491 1492 static struct cue_point * 1493 ne_find_cue_point_for_tstamp(nestegg * ctx, struct ebml_list_node * cue_point, unsigned int track, uint64_t scale, uint64_t tstamp) 1494 { 1495 uint64_t time; 1496 struct cue_point * c, * prev = NULL; 1497 1498 while (cue_point) { 1499 assert(cue_point->id == ID_CUE_POINT); 1500 c = cue_point->data; 1501 1502 if (!prev) 1503 prev = c; 1504 1505 if (ne_get_uint(c->time, &time) == 0 && time * scale > tstamp) 1506 break; 1507 1508 if (ne_find_cue_position_for_track(ctx, c->cue_track_positions.head, track) != NULL) 1509 prev = c; 1510 1511 cue_point = cue_point->next; 1512 } 1513 1514 return prev; 1515 } 1516 1517 static int 1518 ne_is_suspend_element(uint64_t id) 1519 { 1520 if (id == ID_SIMPLE_BLOCK || id == ID_BLOCK) 1521 return 1; 1522 return 0; 1523 } 1524 1525 static void 1526 ne_null_log_callback(nestegg * ctx, unsigned int severity, char const * fmt, ...) 1527 { 1528 if (ctx && severity && fmt) 1529 return; 1530 } 1531 1532 static int 1533 ne_init_cue_points(nestegg * ctx, int64_t max_offset) 1534 { 1535 int r; 1536 struct ebml_list_node * node = ctx->segment.cues.cue_point.head; 1537 struct seek * found; 1538 uint64_t seek_pos, id; 1539 struct saved_state state; 1540 1541 /* If there are no cues loaded, check for cues element in the seek head 1542 and load it. */ 1543 if (!node) { 1544 found = ne_find_seek_for_id(ctx->segment.seek_head.head, ID_CUES); 1545 if (!found) 1546 return -1; 1547 1548 if (ne_get_uint(found->position, &seek_pos) != 0) 1549 return -1; 1550 1551 /* Save old parser state. */ 1552 r = ne_ctx_save(ctx, &state); 1553 if (r != 0) 1554 return -1; 1555 1556 /* Seek and set up parser state for segment-level element (Cues). */ 1557 r = ne_io_seek(ctx->io, ctx->segment_offset + seek_pos, NESTEGG_SEEK_SET); 1558 if (r != 0) 1559 return -1; 1560 ctx->last_valid = 0; 1561 1562 r = ne_read_element(ctx, &id, NULL); 1563 if (r != 1) 1564 return -1; 1565 1566 if (id != ID_CUES) 1567 return -1; 1568 1569 ctx->ancestor = NULL; 1570 ne_ctx_push(ctx, ne_top_level_elements, ctx); 1571 ne_ctx_push(ctx, ne_segment_elements, &ctx->segment); 1572 ne_ctx_push(ctx, ne_cues_elements, &ctx->segment.cues); 1573 /* parser will run until end of cues element. */ 1574 ctx->log(ctx, NESTEGG_LOG_DEBUG, "seek: parsing cue elements"); 1575 r = ne_parse(ctx, ne_cues_elements, max_offset); 1576 while (ctx->ancestor) 1577 ne_ctx_pop(ctx); 1578 1579 /* Reset parser state to original state and seek back to old position. */ 1580 if (ne_ctx_restore(ctx, &state) != 0) 1581 return -1; 1582 1583 if (r < 0) 1584 return -1; 1585 1586 node = ctx->segment.cues.cue_point.head; 1587 if (!node) 1588 return -1; 1589 } 1590 1591 return 0; 1592 } 1593 1594 /* Three functions that implement the nestegg_io interface, operating on a 1595 * sniff_buffer. */ 1596 struct sniff_buffer { 1597 unsigned char const * buffer; 1598 size_t length; 1599 int64_t offset; 1600 }; 1601 1602 static int 1603 ne_buffer_read(void * buffer, size_t length, void * user_data) 1604 { 1605 struct sniff_buffer * sb = user_data; 1606 1607 int rv = 1; 1608 size_t available = sb->length - (size_t)sb->offset; 1609 1610 if (available < length) 1611 return 0; 1612 1613 memcpy(buffer, sb->buffer + sb->offset, length); 1614 sb->offset += length; 1615 1616 return rv; 1617 } 1618 1619 static int 1620 ne_buffer_seek(int64_t offset, int whence, void * user_data) 1621 { 1622 struct sniff_buffer * sb = user_data; 1623 int64_t o = sb->offset; 1624 1625 switch(whence) { 1626 case NESTEGG_SEEK_SET: 1627 o = offset; 1628 break; 1629 case NESTEGG_SEEK_CUR: 1630 o += offset; 1631 break; 1632 case NESTEGG_SEEK_END: 1633 o = sb->length + offset; 1634 break; 1635 } 1636 1637 if (o < 0 || o > (int64_t) sb->length) 1638 return -1; 1639 1640 sb->offset = o; 1641 return 0; 1642 } 1643 1644 static int64_t 1645 ne_buffer_tell(void * user_data) 1646 { 1647 struct sniff_buffer * sb = user_data; 1648 return sb->offset; 1649 } 1650 1651 static int 1652 ne_match_webm(nestegg_io io, int64_t max_offset) 1653 { 1654 int r; 1655 uint64_t id; 1656 char * doctype; 1657 nestegg * ctx; 1658 1659 if (!(io.read && io.seek && io.tell)) 1660 return -1; 1661 1662 ctx = ne_alloc(sizeof(*ctx)); 1663 1664 ctx->io = ne_alloc(sizeof(*ctx->io)); 1665 *ctx->io = io; 1666 ctx->alloc_pool = ne_pool_init(); 1667 ctx->log = ne_null_log_callback; 1668 1669 r = ne_peek_element(ctx, &id, NULL); 1670 if (r != 1) { 1671 nestegg_destroy(ctx); 1672 return 0; 1673 } 1674 1675 if (id != ID_EBML) { 1676 nestegg_destroy(ctx); 1677 return 0; 1678 } 1679 1680 ne_ctx_push(ctx, ne_top_level_elements, ctx); 1681 1682 /* we don't check the return value of ne_parse, that might fail because 1683 * max_offset is not on a valid element end point. We only want to check 1684 * the EBML ID and that the doctype is "webm". */ 1685 ne_parse(ctx, NULL, max_offset); 1686 1687 if (ne_get_string(ctx->ebml.doctype, &doctype) != 0 || 1688 strcmp(doctype, "webm") != 0) { 1689 nestegg_destroy(ctx); 1690 return 0; 1691 } 1692 1693 nestegg_destroy(ctx); 1694 1695 return 1; 1696 } 1697 1698 int 1699 nestegg_init(nestegg ** context, nestegg_io io, nestegg_log callback, int64_t max_offset) 1700 { 1701 int r; 1702 uint64_t id, version, docversion; 1703 struct ebml_list_node * track; 1704 char * doctype; 1705 nestegg * ctx; 1706 1707 if (!(io.read && io.seek && io.tell)) 1708 return -1; 1709 1710 ctx = ne_alloc(sizeof(*ctx)); 1711 1712 ctx->io = ne_alloc(sizeof(*ctx->io)); 1713 *ctx->io = io; 1714 ctx->log = callback; 1715 ctx->alloc_pool = ne_pool_init(); 1716 1717 if (!ctx->log) 1718 ctx->log = ne_null_log_callback; 1719 1720 r = ne_peek_element(ctx, &id, NULL); 1721 if (r != 1) { 1722 nestegg_destroy(ctx); 1723 return -1; 1724 } 1725 1726 if (id != ID_EBML) { 1727 nestegg_destroy(ctx); 1728 return -1; 1729 } 1730 1731 ctx->log(ctx, NESTEGG_LOG_DEBUG, "ctx %p", ctx); 1732 1733 ne_ctx_push(ctx, ne_top_level_elements, ctx); 1734 1735 r = ne_parse(ctx, NULL, max_offset); 1736 1737 if (r != 1) { 1738 nestegg_destroy(ctx); 1739 return -1; 1740 } 1741 1742 if (ne_get_uint(ctx->ebml.ebml_read_version, &version) != 0) 1743 version = 1; 1744 if (version != 1) { 1745 nestegg_destroy(ctx); 1746 return -1; 1747 } 1748 1749 if (ne_get_string(ctx->ebml.doctype, &doctype) != 0) 1750 doctype = "matroska"; 1751 if (strcmp(doctype, "webm") != 0) { 1752 nestegg_destroy(ctx); 1753 return -1; 1754 } 1755 1756 if (ne_get_uint(ctx->ebml.doctype_read_version, &docversion) != 0) 1757 docversion = 1; 1758 if (docversion < 1 || docversion > 2) { 1759 nestegg_destroy(ctx); 1760 return -1; 1761 } 1762 1763 if (!ctx->segment.tracks.track_entry.head) { 1764 nestegg_destroy(ctx); 1765 return -1; 1766 } 1767 1768 track = ctx->segment.tracks.track_entry.head; 1769 ctx->track_count = 0; 1770 1771 while (track) { 1772 ctx->track_count += 1; 1773 track = track->next; 1774 } 1775 1776 *context = ctx; 1777 1778 return 0; 1779 } 1780 1781 void 1782 nestegg_destroy(nestegg * ctx) 1783 { 1784 while (ctx->ancestor) 1785 ne_ctx_pop(ctx); 1786 ne_pool_destroy(ctx->alloc_pool); 1787 free(ctx->io); 1788 free(ctx); 1789 } 1790 1791 int 1792 nestegg_duration(nestegg * ctx, uint64_t * duration) 1793 { 1794 uint64_t tc_scale; 1795 double unscaled_duration; 1796 1797 if (ne_get_float(ctx->segment.info.duration, &unscaled_duration) != 0) 1798 return -1; 1799 1800 tc_scale = ne_get_timecode_scale(ctx); 1801 1802 *duration = (uint64_t) (unscaled_duration * tc_scale); 1803 return 0; 1804 } 1805 1806 int 1807 nestegg_tstamp_scale(nestegg * ctx, uint64_t * scale) 1808 { 1809 *scale = ne_get_timecode_scale(ctx); 1810 return 0; 1811 } 1812 1813 int 1814 nestegg_track_count(nestegg * ctx, unsigned int * tracks) 1815 { 1816 *tracks = ctx->track_count; 1817 return 0; 1818 } 1819 1820 int 1821 nestegg_get_cue_point(nestegg * ctx, unsigned int cluster_num, int64_t max_offset, 1822 int64_t * start_pos, int64_t * end_pos, uint64_t * tstamp) 1823 { 1824 int range_obtained = 0; 1825 unsigned int cluster_count = 0; 1826 struct cue_point * cue_point; 1827 struct cue_track_positions * pos; 1828 uint64_t seek_pos, track_number, tc_scale, time; 1829 struct ebml_list_node * cues_node = ctx->segment.cues.cue_point.head; 1830 struct ebml_list_node * cue_pos_node = NULL; 1831 unsigned int track = 0, track_count = 0, track_index; 1832 1833 if (!start_pos || !end_pos || !tstamp) 1834 return -1; 1835 1836 /* Initialise return values */ 1837 *start_pos = -1; 1838 *end_pos = -1; 1839 *tstamp = 0; 1840 1841 if (!cues_node) { 1842 ne_init_cue_points(ctx, max_offset); 1843 cues_node = ctx->segment.cues.cue_point.head; 1844 /* Verify cues have been added to context. */ 1845 if (!cues_node) 1846 return -1; 1847 } 1848 1849 nestegg_track_count(ctx, &track_count); 1850 1851 tc_scale = ne_get_timecode_scale(ctx); 1852 1853 while (cues_node && !range_obtained) { 1854 assert(cues_node->id == ID_CUE_POINT); 1855 cue_point = cues_node->data; 1856 cue_pos_node = cue_point->cue_track_positions.head; 1857 while (cue_pos_node) { 1858 assert(cue_pos_node->id == ID_CUE_TRACK_POSITIONS); 1859 pos = cue_pos_node->data; 1860 for (track = 0; track < track_count; track++) { 1861 if (ne_get_uint(pos->track, &track_number) != 0) 1862 return -1; 1863 1864 if (ne_map_track_number_to_index(ctx, (unsigned int)track_number, &track_index) != 0) 1865 return -1; 1866 1867 if (track_index == track) { 1868 if (ne_get_uint(pos->cluster_position, &seek_pos) != 0) 1869 return -1; 1870 if (cluster_count == cluster_num) { 1871 *start_pos = ctx->segment_offset+seek_pos; 1872 if (ne_get_uint(cue_point->time, &time) != 0) 1873 return -1; 1874 *tstamp = time * tc_scale; 1875 } else if (cluster_count == cluster_num+1) { 1876 *end_pos = (ctx->segment_offset+seek_pos)-1; 1877 range_obtained = 1; 1878 break; 1879 } 1880 cluster_count++; 1881 } 1882 } 1883 cue_pos_node = cue_pos_node->next; 1884 } 1885 cues_node = cues_node->next; 1886 } 1887 1888 return 0; 1889 } 1890 1891 int 1892 nestegg_offset_seek(nestegg * ctx, uint64_t offset) 1893 { 1894 int r; 1895 1896 /* Seek and set up parser state for segment-level element (Cluster). */ 1897 r = ne_io_seek(ctx->io, offset, NESTEGG_SEEK_SET); 1898 if (r != 0) 1899 return -1; 1900 ctx->last_valid = 0; 1901 1902 while (ctx->ancestor) 1903 ne_ctx_pop(ctx); 1904 1905 ne_ctx_push(ctx, ne_top_level_elements, ctx); 1906 ne_ctx_push(ctx, ne_segment_elements, &ctx->segment); 1907 1908 return 0; 1909 } 1910 1911 int 1912 nestegg_track_seek(nestegg * ctx, unsigned int track, uint64_t tstamp) 1913 { 1914 int r; 1915 struct cue_point * cue_point; 1916 struct cue_track_positions * pos; 1917 uint64_t seek_pos, tc_scale; 1918 1919 /* If there are no cues loaded, check for cues element in the seek head 1920 and load it. */ 1921 if (!ctx->segment.cues.cue_point.head) { 1922 r = ne_init_cue_points(ctx, -1); 1923 if (r != 0) 1924 return -1; 1925 } 1926 1927 tc_scale = ne_get_timecode_scale(ctx); 1928 1929 cue_point = ne_find_cue_point_for_tstamp(ctx, ctx->segment.cues.cue_point.head, 1930 track, tc_scale, tstamp); 1931 if (!cue_point) 1932 return -1; 1933 1934 pos = ne_find_cue_position_for_track(ctx, cue_point->cue_track_positions.head, track); 1935 if (pos == NULL) 1936 return -1; 1937 1938 if (ne_get_uint(pos->cluster_position, &seek_pos) != 0) 1939 return -1; 1940 1941 /* Seek and set up parser state for segment-level element (Cluster). */ 1942 r = nestegg_offset_seek(ctx, ctx->segment_offset + seek_pos); 1943 ctx->log(ctx, NESTEGG_LOG_DEBUG, "seek: parsing cluster elements"); 1944 r = ne_parse(ctx, NULL, -1); 1945 if (r != 1) 1946 return -1; 1947 1948 if (!ne_is_suspend_element(ctx->last_id)) 1949 return -1; 1950 1951 return 0; 1952 } 1953 1954 int 1955 nestegg_track_type(nestegg * ctx, unsigned int track) 1956 { 1957 struct track_entry * entry; 1958 uint64_t type; 1959 1960 entry = ne_find_track_entry(ctx, track); 1961 if (!entry) 1962 return -1; 1963 1964 if (ne_get_uint(entry->type, &type) != 0) 1965 return -1; 1966 1967 if (type & TRACK_TYPE_VIDEO) 1968 return NESTEGG_TRACK_VIDEO; 1969 1970 if (type & TRACK_TYPE_AUDIO) 1971 return NESTEGG_TRACK_AUDIO; 1972 1973 return -1; 1974 } 1975 1976 int 1977 nestegg_track_codec_id(nestegg * ctx, unsigned int track) 1978 { 1979 char * codec_id; 1980 struct track_entry * entry; 1981 1982 entry = ne_find_track_entry(ctx, track); 1983 if (!entry) 1984 return -1; 1985 1986 if (ne_get_string(entry->codec_id, &codec_id) != 0) 1987 return -1; 1988 1989 if (strcmp(codec_id, TRACK_ID_VP8) == 0) 1990 return NESTEGG_CODEC_VP8; 1991 1992 if (strcmp(codec_id, TRACK_ID_VP9) == 0) 1993 return NESTEGG_CODEC_VP9; 1994 1995 if (strcmp(codec_id, TRACK_ID_VORBIS) == 0) 1996 return NESTEGG_CODEC_VORBIS; 1997 1998 if (strcmp(codec_id, TRACK_ID_OPUS) == 0) 1999 return NESTEGG_CODEC_OPUS; 2000 2001 return -1; 2002 } 2003 2004 int 2005 nestegg_track_codec_data_count(nestegg * ctx, unsigned int track, 2006 unsigned int * count) 2007 { 2008 struct track_entry * entry; 2009 struct ebml_binary codec_private; 2010 unsigned char * p; 2011 2012 *count = 0; 2013 2014 entry = ne_find_track_entry(ctx, track); 2015 if (!entry) 2016 return -1; 2017 2018 if (nestegg_track_codec_id(ctx, track) != NESTEGG_CODEC_VORBIS) 2019 return -1; 2020 2021 if (ne_get_binary(entry->codec_private, &codec_private) != 0) 2022 return -1; 2023 2024 if (codec_private.length < 1) 2025 return -1; 2026 2027 p = codec_private.data; 2028 *count = *p + 1; 2029 2030 if (*count > 3) 2031 return -1; 2032 2033 return 0; 2034 } 2035 2036 int 2037 nestegg_track_codec_data(nestegg * ctx, unsigned int track, unsigned int item, 2038 unsigned char ** data, size_t * length) 2039 { 2040 struct track_entry * entry; 2041 struct ebml_binary codec_private; 2042 uint64_t sizes[3], total; 2043 unsigned char * p; 2044 unsigned int count, i; 2045 2046 *data = NULL; 2047 *length = 0; 2048 2049 entry = ne_find_track_entry(ctx, track); 2050 if (!entry) 2051 return -1; 2052 2053 if (nestegg_track_codec_id(ctx, track) != NESTEGG_CODEC_VORBIS 2054 && nestegg_track_codec_id(ctx, track) != NESTEGG_CODEC_OPUS) 2055 return -1; 2056 2057 if (ne_get_binary(entry->codec_private, &codec_private) != 0) 2058 return -1; 2059 2060 if (nestegg_track_codec_id(ctx, track) == NESTEGG_CODEC_VORBIS) { 2061 p = codec_private.data; 2062 count = *p++ + 1; 2063 2064 if (count > 3) 2065 return -1; 2066 2067 i = 0; 2068 total = 0; 2069 while (--count) { 2070 sizes[i] = ne_xiph_lace_value(&p); 2071 total += sizes[i]; 2072 i += 1; 2073 } 2074 sizes[i] = codec_private.length - total - (p - codec_private.data); 2075 2076 for (i = 0; i < item; ++i) { 2077 if (sizes[i] > LIMIT_FRAME) 2078 return -1; 2079 p += sizes[i]; 2080 } 2081 *data = p; 2082 *length = (size_t)sizes[item]; 2083 } else { 2084 *data = codec_private.data; 2085 *length = codec_private.length; 2086 } 2087 2088 return 0; 2089 } 2090 2091 int 2092 nestegg_track_video_params(nestegg * ctx, unsigned int track, 2093 nestegg_video_params * params) 2094 { 2095 struct track_entry * entry; 2096 unsigned int value; 2097 2098 memset(params, 0, sizeof(*params)); 2099 2100 entry = ne_find_track_entry(ctx, track); 2101 if (!entry) 2102 return -1; 2103 2104 if (nestegg_track_type(ctx, track) != NESTEGG_TRACK_VIDEO) 2105 return -1; 2106 2107 value = 0; 2108 ne_get_uint32(entry->video.stereo_mode, &value); 2109 if (value <= NESTEGG_VIDEO_STEREO_TOP_BOTTOM || 2110 value == NESTEGG_VIDEO_STEREO_RIGHT_LEFT) 2111 params->stereo_mode = value; 2112 2113 if (ne_get_uint32(entry->video.pixel_width, &value) != 0) 2114 return -1; 2115 params->width = value; 2116 2117 if (ne_get_uint32(entry->video.pixel_height, &value) != 0) 2118 return -1; 2119 params->height = value; 2120 2121 value = 0; 2122 ne_get_uint32(entry->video.pixel_crop_bottom, &value); 2123 params->crop_bottom = value; 2124 2125 value = 0; 2126 ne_get_uint32(entry->video.pixel_crop_top, &value); 2127 params->crop_top = value; 2128 2129 value = 0; 2130 ne_get_uint32(entry->video.pixel_crop_left, &value); 2131 params->crop_left = value; 2132 2133 value = 0; 2134 ne_get_uint32(entry->video.pixel_crop_right, &value); 2135 params->crop_right = value; 2136 2137 value = params->width; 2138 ne_get_uint32(entry->video.display_width, &value); 2139 params->display_width = value; 2140 2141 value = params->height; 2142 ne_get_uint32(entry->video.display_height, &value); 2143 params->display_height = value; 2144 2145 return 0; 2146 } 2147 2148 int 2149 nestegg_track_audio_params(nestegg * ctx, unsigned int track, 2150 nestegg_audio_params * params) 2151 { 2152 struct track_entry * entry; 2153 unsigned int value; 2154 2155 memset(params, 0, sizeof(*params)); 2156 2157 entry = ne_find_track_entry(ctx, track); 2158 if (!entry) 2159 return -1; 2160 2161 if (nestegg_track_type(ctx, track) != NESTEGG_TRACK_AUDIO) 2162 return -1; 2163 2164 params->rate = 8000; 2165 ne_get_float(entry->audio.sampling_frequency, ¶ms->rate); 2166 2167 value = 1; 2168 ne_get_uint32(entry->audio.channels, &value); 2169 params->channels = value; 2170 2171 value = 16; 2172 ne_get_uint32(entry->audio.bit_depth, &value); 2173 params->depth = value; 2174 2175 value = 0; 2176 ne_get_uint32(entry->codec_delay, &value); 2177 params->codec_delay = value; 2178 2179 value = 0; 2180 ne_get_uint32(entry->seek_preroll, &value); 2181 params->seek_preroll = value; 2182 2183 return 0; 2184 } 2185 2186 int 2187 nestegg_read_packet(nestegg * ctx, nestegg_packet ** pkt) 2188 { 2189 int r; 2190 uint64_t id, size; 2191 2192 *pkt = NULL; 2193 2194 for (;;) { 2195 r = ne_peek_element(ctx, &id, &size); 2196 if (r != 1) 2197 return r; 2198 2199 /* Any DESC_FLAG_SUSPEND fields must be handled here. */ 2200 if (ne_is_suspend_element(id)) { 2201 r = ne_read_element(ctx, &id, &size); 2202 if (r != 1) 2203 return r; 2204 2205 /* The only DESC_FLAG_SUSPEND fields are Blocks and SimpleBlocks, which we 2206 handle directly. */ 2207 r = ne_read_block(ctx, id, size, pkt); 2208 if (r != 1) 2209 return r; 2210 2211 r = ne_read_discard_padding(ctx, *pkt); 2212 if (r != 1) 2213 return r; 2214 2215 return r; 2216 } 2217 2218 r = ne_parse(ctx, NULL, -1); 2219 if (r != 1) 2220 return r; 2221 } 2222 2223 return 1; 2224 } 2225 2226 void 2227 nestegg_free_packet(nestegg_packet * pkt) 2228 { 2229 struct frame * frame; 2230 2231 while (pkt->frame) { 2232 frame = pkt->frame; 2233 pkt->frame = frame->next; 2234 free(frame->data); 2235 free(frame); 2236 } 2237 2238 free(pkt); 2239 } 2240 2241 int 2242 nestegg_packet_track(nestegg_packet * pkt, unsigned int * track) 2243 { 2244 *track = (unsigned int)pkt->track; 2245 return 0; 2246 } 2247 2248 int 2249 nestegg_packet_tstamp(nestegg_packet * pkt, uint64_t * tstamp) 2250 { 2251 *tstamp = pkt->timecode; 2252 return 0; 2253 } 2254 2255 int 2256 nestegg_packet_discard_padding(nestegg_packet * pkt, int64_t * discard_padding) 2257 { 2258 *discard_padding = pkt->discard_padding; 2259 return 0; 2260 } 2261 2262 int 2263 nestegg_packet_count(nestegg_packet * pkt, unsigned int * count) 2264 { 2265 struct frame * f = pkt->frame; 2266 2267 *count = 0; 2268 2269 while (f) { 2270 *count += 1; 2271 f = f->next; 2272 } 2273 2274 return 0; 2275 } 2276 2277 int 2278 nestegg_packet_data(nestegg_packet * pkt, unsigned int item, 2279 unsigned char ** data, size_t * length) 2280 { 2281 struct frame * f = pkt->frame; 2282 unsigned int count = 0; 2283 2284 *data = NULL; 2285 *length = 0; 2286 2287 while (f) { 2288 if (count == item) { 2289 *data = f->data; 2290 *length = f->length; 2291 return 0; 2292 } 2293 count += 1; 2294 f = f->next; 2295 } 2296 2297 return -1; 2298 } 2299 2300 int 2301 nestegg_has_cues(nestegg * ctx) 2302 { 2303 return ctx->segment.cues.cue_point.head || 2304 ne_find_seek_for_id(ctx->segment.seek_head.head, ID_CUES); 2305 } 2306 2307 int 2308 nestegg_sniff(unsigned char const * buffer, size_t length) 2309 { 2310 nestegg_io io; 2311 struct sniff_buffer user_data; 2312 2313 user_data.buffer = buffer; 2314 user_data.length = length; 2315 user_data.offset = 0; 2316 2317 io.read = ne_buffer_read; 2318 io.seek = ne_buffer_seek; 2319 io.tell = ne_buffer_tell; 2320 io.userdata = &user_data; 2321 return ne_match_webm(io, length); 2322 } 2323 2324
