git.sesse.net Git - ffmpeg/blob - libavformat/matroska.c

   1 /*
   2  * Matroska file demuxer (no muxer yet)
   3  * Copyright (c) 2003-2004 The ffmpeg Project
   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 matroska.c
  24  * Matroska file demuxer
  25  * by Ronald Bultje <rbultje@ronald.bitfreak.net>
  26  * with a little help from Moritz Bunkus <moritz@bunkus.org>
  27  * Specs available on the matroska project page:
  28  * http://www.matroska.org/.
  29  */
  30
  31 #include "avformat.h"
  32 /* For codec_get_id(). */
  33 #include "riff.h"
  34 #include "intfloat_readwrite.h"
  35
  36 /* EBML version supported */
  37 #define EBML_VERSION 1
  38
  39 /* top-level master-IDs */
  40 #define EBML_ID_HEADER             0x1A45DFA3
  41
  42 /* IDs in the HEADER master */
  43 #define EBML_ID_EBMLVERSION        0x4286
  44 #define EBML_ID_EBMLREADVERSION    0x42F7
  45 #define EBML_ID_EBMLMAXIDLENGTH    0x42F2
  46 #define EBML_ID_EBMLMAXSIZELENGTH  0x42F3
  47 #define EBML_ID_DOCTYPE            0x4282
  48 #define EBML_ID_DOCTYPEVERSION     0x4287
  49 #define EBML_ID_DOCTYPEREADVERSION 0x4285
  50
  51 /* general EBML types */
  52 #define EBML_ID_VOID               0xEC
  53
  54 /*
  55  * Matroska element IDs. max. 32-bit.
  56  */
  57
  58 /* toplevel segment */
  59 #define MATROSKA_ID_SEGMENT    0x18538067
  60
  61 /* matroska top-level master IDs */
  62 #define MATROSKA_ID_INFO       0x1549A966
  63 #define MATROSKA_ID_TRACKS     0x1654AE6B
  64 #define MATROSKA_ID_CUES       0x1C53BB6B
  65 #define MATROSKA_ID_TAGS       0x1254C367
  66 #define MATROSKA_ID_SEEKHEAD   0x114D9B74
  67 #define MATROSKA_ID_CLUSTER    0x1F43B675
  68
  69 /* IDs in the info master */
  70 #define MATROSKA_ID_TIMECODESCALE 0x2AD7B1
  71 #define MATROSKA_ID_DURATION   0x4489
  72 #define MATROSKA_ID_TITLE      0x7BA9
  73 #define MATROSKA_ID_WRITINGAPP 0x5741
  74 #define MATROSKA_ID_MUXINGAPP  0x4D80
  75 #define MATROSKA_ID_DATEUTC    0x4461
  76
  77 /* ID in the tracks master */
  78 #define MATROSKA_ID_TRACKENTRY 0xAE
  79
  80 /* IDs in the trackentry master */
  81 #define MATROSKA_ID_TRACKNUMBER 0xD7
  82 #define MATROSKA_ID_TRACKUID   0x73C5
  83 #define MATROSKA_ID_TRACKTYPE  0x83
  84 #define MATROSKA_ID_TRACKAUDIO 0xE1
  85 #define MATROSKA_ID_TRACKVIDEO 0xE0
  86 #define MATROSKA_ID_CODECID    0x86
  87 #define MATROSKA_ID_CODECPRIVATE 0x63A2
  88 #define MATROSKA_ID_CODECNAME  0x258688
  89 #define MATROSKA_ID_CODECINFOURL 0x3B4040
  90 #define MATROSKA_ID_CODECDOWNLOADURL 0x26B240
  91 #define MATROSKA_ID_TRACKNAME  0x536E
  92 #define MATROSKA_ID_TRACKLANGUAGE 0x22B59C
  93 #define MATROSKA_ID_TRACKFLAGENABLED 0xB9
  94 #define MATROSKA_ID_TRACKFLAGDEFAULT 0x88
  95 #define MATROSKA_ID_TRACKFLAGLACING 0x9C
  96 #define MATROSKA_ID_TRACKMINCACHE 0x6DE7
  97 #define MATROSKA_ID_TRACKMAXCACHE 0x6DF8
  98 #define MATROSKA_ID_TRACKDEFAULTDURATION 0x23E383
  99
 100 /* IDs in the trackvideo master */
 101 #define MATROSKA_ID_VIDEOFRAMERATE 0x2383E3
 102 #define MATROSKA_ID_VIDEODISPLAYWIDTH 0x54B0
 103 #define MATROSKA_ID_VIDEODISPLAYHEIGHT 0x54BA
 104 #define MATROSKA_ID_VIDEOPIXELWIDTH 0xB0
 105 #define MATROSKA_ID_VIDEOPIXELHEIGHT 0xBA
 106 #define MATROSKA_ID_VIDEOFLAGINTERLACED 0x9A
 107 #define MATROSKA_ID_VIDEOSTEREOMODE 0x53B9
 108 #define MATROSKA_ID_VIDEOASPECTRATIO 0x54B3
 109 #define MATROSKA_ID_VIDEOCOLOURSPACE 0x2EB524
 110
 111 /* IDs in the trackaudio master */
 112 #define MATROSKA_ID_AUDIOSAMPLINGFREQ 0xB5
 113 #define MATROSKA_ID_AUDIOOUTSAMPLINGFREQ 0x78B5
 114
 115 #define MATROSKA_ID_AUDIOBITDEPTH 0x6264
 116 #define MATROSKA_ID_AUDIOCHANNELS 0x9F
 117
 118 /* ID in the cues master */
 119 #define MATROSKA_ID_POINTENTRY 0xBB
 120
 121 /* IDs in the pointentry master */
 122 #define MATROSKA_ID_CUETIME    0xB3
 123 #define MATROSKA_ID_CUETRACKPOSITION 0xB7
 124
 125 /* IDs in the cuetrackposition master */
 126 #define MATROSKA_ID_CUETRACK   0xF7
 127 #define MATROSKA_ID_CUECLUSTERPOSITION 0xF1
 128
 129 /* IDs in the tags master */
 130 /* TODO */
 131
 132 /* IDs in the seekhead master */
 133 #define MATROSKA_ID_SEEKENTRY  0x4DBB
 134
 135 /* IDs in the seekpoint master */
 136 #define MATROSKA_ID_SEEKID     0x53AB
 137 #define MATROSKA_ID_SEEKPOSITION 0x53AC
 138
 139 /* IDs in the cluster master */
 140 #define MATROSKA_ID_CLUSTERTIMECODE 0xE7
 141 #define MATROSKA_ID_BLOCKGROUP 0xA0
 142 #define MATROSKA_ID_SIMPLEBLOCK 0xA3
 143
 144 /* IDs in the blockgroup master */
 145 #define MATROSKA_ID_BLOCK      0xA1
 146 #define MATROSKA_ID_BLOCKDURATION 0x9B
 147 #define MATROSKA_ID_BLOCKREFERENCE 0xFB
 148
 149 typedef enum {
 150   MATROSKA_TRACK_TYPE_VIDEO    = 0x1,
 151   MATROSKA_TRACK_TYPE_AUDIO    = 0x2,
 152   MATROSKA_TRACK_TYPE_COMPLEX  = 0x3,
 153   MATROSKA_TRACK_TYPE_LOGO     = 0x10,
 154   MATROSKA_TRACK_TYPE_SUBTITLE = 0x11,
 155   MATROSKA_TRACK_TYPE_CONTROL  = 0x20,
 156 } MatroskaTrackType;
 157
 158 typedef enum {
 159   MATROSKA_EYE_MODE_MONO  = 0x0,
 160   MATROSKA_EYE_MODE_RIGHT = 0x1,
 161   MATROSKA_EYE_MODE_LEFT  = 0x2,
 162   MATROSKA_EYE_MODE_BOTH  = 0x3,
 163 } MatroskaEyeMode;
 164
 165 typedef enum {
 166   MATROSKA_ASPECT_RATIO_MODE_FREE  = 0x0,
 167   MATROSKA_ASPECT_RATIO_MODE_KEEP  = 0x1,
 168   MATROSKA_ASPECT_RATIO_MODE_FIXED = 0x2,
 169 } MatroskaAspectRatioMode;
 170
 171 /*
 172  * These aren't in any way "matroska-form" things,
 173  * it's just something I use in the muxer/demuxer.
 174  */
 175
 176 typedef enum {
 177   MATROSKA_TRACK_ENABLED = (1<<0),
 178   MATROSKA_TRACK_DEFAULT = (1<<1),
 179   MATROSKA_TRACK_LACING  = (1<<2),
 180   MATROSKA_TRACK_REAL_V  = (1<<4),
 181   MATROSKA_TRACK_REORDER = (1<<8),
 182   MATROSKA_TRACK_SHIFT   = (1<<16)
 183 } MatroskaTrackFlags;
 184
 185 typedef enum {
 186   MATROSKA_VIDEOTRACK_INTERLACED = (MATROSKA_TRACK_SHIFT<<0)
 187 } MatroskaVideoTrackFlags;
 188
 189 /*
 190  * Matroska Codec IDs. Strings.
 191  */
 192
 193 typedef struct CodecTags{
 194     const char *str;
 195     enum CodecID id;
 196 }CodecTags;
 197
 198 #define MATROSKA_CODEC_ID_VIDEO_VFW_FOURCC   "V_MS/VFW/FOURCC"
 199 #define MATROSKA_CODEC_ID_AUDIO_ACM          "A_MS/ACM"
 200
 201 static CodecTags codec_tags[]={
 202 //    {"V_MS/VFW/FOURCC"  , CODEC_ID_NONE},
 203     {"V_UNCOMPRESSED"   , CODEC_ID_RAWVIDEO},
 204     {"V_MPEG4/ISO/SP"   , CODEC_ID_MPEG4},
 205     {"V_MPEG4/ISO/ASP"  , CODEC_ID_MPEG4},
 206     {"V_MPEG4/ISO/AP"   , CODEC_ID_MPEG4},
 207     {"V_MPEG4/ISO/AVC"  , CODEC_ID_H264},
 208     {"V_MPEG4/MS/V3"    , CODEC_ID_MSMPEG4V3},
 209     {"V_MPEG1"          , CODEC_ID_MPEG1VIDEO},
 210     {"V_MPEG2"          , CODEC_ID_MPEG2VIDEO},
 211     {"V_MJPEG"          , CODEC_ID_MJPEG},
 212     {"V_REAL/RV10"      , CODEC_ID_RV10},
 213     {"V_REAL/RV20"      , CODEC_ID_RV20},
 214     {"V_REAL/RV30"      , CODEC_ID_RV30},
 215     {"V_REAL/RV40"      , CODEC_ID_RV40},
 216     {"V_THEORA"         , CODEC_ID_THEORA},
 217 /* TODO: Real/Quicktime */
 218
 219 //    {"A_MS/ACM"         , CODEC_ID_NONE},
 220     {"A_MPEG/L1"        , CODEC_ID_MP3},
 221     {"A_MPEG/L2"        , CODEC_ID_MP3},
 222     {"A_MPEG/L3"        , CODEC_ID_MP3},
 223     {"A_PCM/INT/BIG"    , CODEC_ID_PCM_U16BE},
 224     {"A_PCM/INT/LIT"    , CODEC_ID_PCM_U16LE},
 225 //    {"A_PCM/FLOAT/IEEE" , CODEC_ID_NONE},
 226     {"A_AC3"            , CODEC_ID_AC3},
 227     {"A_DTS"            , CODEC_ID_DTS},
 228     {"A_VORBIS"         , CODEC_ID_VORBIS},
 229     {"A_AAC"            , CODEC_ID_AAC},
 230     {"A_FLAC"           , CODEC_ID_FLAC},
 231     {"A_WAVPACK4"       , CODEC_ID_WAVPACK},
 232     {"A_TTA1"           , CODEC_ID_TTA},
 233     {NULL               , CODEC_ID_NONE}
 234 /* TODO: AC3-9/10 (?), Real, Musepack, Quicktime */
 235 };
 236
 237 /* max. depth in the EBML tree structure */
 238 #define EBML_MAX_DEPTH 16
 239
 240 typedef struct Track {
 241     MatroskaTrackType type;
 242
 243     /* Unique track number and track ID. stream_index is the index that
 244      * the calling app uses for this track. */
 245     uint32_t num,
 246         uid,
 247         stream_index;
 248
 249     char *name,
 250         *language;
 251
 252     char *codec_id,
 253         *codec_name;
 254
 255     unsigned char *codec_priv;
 256     int codec_priv_size;
 257
 258     uint64_t default_duration;
 259     MatroskaTrackFlags flags;
 260 } MatroskaTrack;
 261
 262 typedef struct MatroskaVideoTrack {
 263     MatroskaTrack track;
 264
 265     int pixel_width,
 266         pixel_height,
 267         display_width,
 268         display_height;
 269
 270     uint32_t fourcc;
 271
 272     MatroskaAspectRatioMode ar_mode;
 273     MatroskaEyeMode eye_mode;
 274
 275     //..
 276 } MatroskaVideoTrack;
 277
 278 typedef struct MatroskaAudioTrack {
 279     MatroskaTrack track;
 280
 281     int channels,
 282         bitdepth,
 283         internal_samplerate,
 284         samplerate;
 285     //..
 286 } MatroskaAudioTrack;
 287
 288 typedef struct MatroskaSubtitleTrack {
 289     MatroskaTrack track;
 290
 291     //..
 292 } MatroskaSubtitleTrack;
 293
 294 #define MAX_TRACK_SIZE (FFMAX(FFMAX(sizeof(MatroskaVideoTrack), \
 295                                     sizeof(MatroskaAudioTrack)), \
 296                                     sizeof(MatroskaSubtitleTrack)))
 297
 298 typedef struct MatroskaLevel {
 299     uint64_t start, length;
 300 } MatroskaLevel;
 301
 302 typedef struct MatroskaDemuxIndex {
 303   uint64_t        pos;   /* of the corresponding *cluster*! */
 304   uint16_t        track; /* reference to 'num' */
 305   uint64_t        time;  /* in nanoseconds */
 306 } MatroskaDemuxIndex;
 307
 308 typedef struct MatroskaDemuxContext {
 309     AVFormatContext *ctx;
 310
 311     /* ebml stuff */
 312     int num_levels;
 313     MatroskaLevel levels[EBML_MAX_DEPTH];
 314     int level_up;
 315
 316     /* matroska stuff */
 317     char *writing_app,
 318         *muxing_app;
 319     int64_t created;
 320
 321     /* timescale in the file */
 322     int64_t time_scale;
 323
 324     /* position (time, ns) */
 325     int64_t pos;
 326
 327     /* num_streams is the number of streams that av_new_stream() was called
 328      * for ( = that are available to the calling program). */
 329     int num_tracks, num_streams;
 330     MatroskaTrack *tracks[MAX_STREAMS];
 331
 332     /* cache for ID peeking */
 333     uint32_t peek_id;
 334
 335     /* byte position of the segment inside the stream */
 336     offset_t segment_start;
 337
 338     /* The packet queue. */
 339     AVPacket **packets;
 340     int num_packets;
 341     /* Second packet queue used to reorder pts of some video track. */
 342     AVPacket **packets_reorder;
 343     int num_packets_reorder;
 344     uint64_t reorder_max_pts;
 345
 346     /* have we already parse metadata/cues/clusters? */
 347     int metadata_parsed,
 348         index_parsed,
 349         done;
 350
 351     /* The index for seeking. */
 352     int num_indexes;
 353     MatroskaDemuxIndex *index;
 354 } MatroskaDemuxContext;
 355
 356 /*
 357  * The first few functions handle EBML file parsing. The rest
 358  * is the document interpretation. Matroska really just is a
 359  * EBML file.
 360  */
 361
 362 /*
 363  * Return: the amount of levels in the hierarchy that the
 364  * current element lies higher than the previous one.
 365  * The opposite isn't done - that's auto-done using master
 366  * element reading.
 367  */
 368
 369 static int
 370 ebml_read_element_level_up (MatroskaDemuxContext *matroska)
 371 {
 372     ByteIOContext *pb = &matroska->ctx->pb;
 373     offset_t pos = url_ftell(pb);
 374     int num = 0;
 375
 376     while (matroska->num_levels > 0) {
 377         MatroskaLevel *level = &matroska->levels[matroska->num_levels - 1];
 378
 379         if (pos >= level->start + level->length) {
 380             matroska->num_levels--;
 381             num++;
 382         } else {
 383             break;
 384         }
 385     }
 386
 387     return num;
 388 }
 389
 390 /*
 391  * Read: an "EBML number", which is defined as a variable-length
 392  * array of bytes. The first byte indicates the length by giving a
 393  * number of 0-bits followed by a one. The position of the first
 394  * "one" bit inside the first byte indicates the length of this
 395  * number.
 396  * Returns: num. of bytes read. < 0 on error.
 397  */
 398
 399 static int
 400 ebml_read_num (MatroskaDemuxContext *matroska,
 401                int                   max_size,
 402                uint64_t             *number)
 403 {
 404     ByteIOContext *pb = &matroska->ctx->pb;
 405     int len_mask = 0x80, read = 1, n = 1;
 406     int64_t total = 0;
 407
 408     /* the first byte tells us the length in bytes - get_byte() can normally
 409      * return 0, but since that's not a valid first ebmlID byte, we can
 410      * use it safely here to catch EOS. */
 411     if (!(total = get_byte(pb))) {
 412         /* we might encounter EOS here */
 413         if (!url_feof(pb)) {
 414             offset_t pos = url_ftell(pb);
 415             av_log(matroska->ctx, AV_LOG_ERROR,
 416                    "Read error at pos. %"PRIu64" (0x%"PRIx64")\n",
 417                    pos, pos);
 418         }
 419         return AVERROR_IO; /* EOS or actual I/O error */
 420     }
 421
 422     /* get the length of the EBML number */
 423     while (read <= max_size && !(total & len_mask)) {
 424         read++;
 425         len_mask >>= 1;
 426     }
 427     if (read > max_size) {
 428         offset_t pos = url_ftell(pb) - 1;
 429         av_log(matroska->ctx, AV_LOG_ERROR,
 430                "Invalid EBML number size tag 0x%02x at pos %"PRIu64" (0x%"PRIx64")\n",
 431                (uint8_t) total, pos, pos);
 432         return AVERROR_INVALIDDATA;
 433     }
 434
 435     /* read out length */
 436     total &= ~len_mask;
 437     while (n++ < read)
 438         total = (total << 8) | get_byte(pb);
 439
 440     *number = total;
 441
 442     return read;
 443 }
 444
 445 /*
 446  * Read: the element content data ID.
 447  * Return: the number of bytes read or < 0 on error.
 448  */
 449
 450 static int
 451 ebml_read_element_id (MatroskaDemuxContext *matroska,
 452                       uint32_t             *id,
 453                       int                  *level_up)
 454 {
 455     int read;
 456     uint64_t total;
 457
 458     /* if we re-call this, use our cached ID */
 459     if (matroska->peek_id != 0) {
 460         if (level_up)
 461             *level_up = 0;
 462         *id = matroska->peek_id;
 463         return 0;
 464     }
 465
 466     /* read out the "EBML number", include tag in ID */
 467     if ((read = ebml_read_num(matroska, 4, &total)) < 0)
 468         return read;
 469     *id = matroska->peek_id  = total | (1 << (read * 7));
 470
 471     /* level tracking */
 472     if (level_up)
 473         *level_up = ebml_read_element_level_up(matroska);
 474
 475     return read;
 476 }
 477
 478 /*
 479  * Read: element content length.
 480  * Return: the number of bytes read or < 0 on error.
 481  */
 482
 483 static int
 484 ebml_read_element_length (MatroskaDemuxContext *matroska,
 485                           uint64_t             *length)
 486 {
 487     /* clear cache since we're now beyond that data point */
 488     matroska->peek_id = 0;
 489
 490     /* read out the "EBML number", include tag in ID */
 491     return ebml_read_num(matroska, 8, length);
 492 }
 493
 494 /*
 495  * Return: the ID of the next element, or 0 on error.
 496  * Level_up contains the amount of levels that this
 497  * next element lies higher than the previous one.
 498  */
 499
 500 static uint32_t
 501 ebml_peek_id (MatroskaDemuxContext *matroska,
 502               int                  *level_up)
 503 {
 504     uint32_t id;
 505
 506     assert(level_up != NULL);
 507
 508     if (ebml_read_element_id(matroska, &id, level_up) < 0)
 509         return 0;
 510
 511     return id;
 512 }
 513
 514 /*
 515  * Seek to a given offset.
 516  * 0 is success, -1 is failure.
 517  */
 518
 519 static int
 520 ebml_read_seek (MatroskaDemuxContext *matroska,
 521                 offset_t              offset)
 522 {
 523     ByteIOContext *pb = &matroska->ctx->pb;
 524
 525     /* clear ID cache, if any */
 526     matroska->peek_id = 0;
 527
 528     return (url_fseek(pb, offset, SEEK_SET) == offset) ? 0 : -1;
 529 }
 530
 531 /*
 532  * Skip the next element.
 533  * 0 is success, -1 is failure.
 534  */
 535
 536 static int
 537 ebml_read_skip (MatroskaDemuxContext *matroska)
 538 {
 539     ByteIOContext *pb = &matroska->ctx->pb;
 540     uint32_t id;
 541     uint64_t length;
 542     int res;
 543
 544     if ((res = ebml_read_element_id(matroska, &id, NULL)) < 0 ||
 545         (res = ebml_read_element_length(matroska, &length)) < 0)
 546         return res;
 547
 548     url_fskip(pb, length);
 549
 550     return 0;
 551 }
 552
 553 /*
 554  * Read the next element as an unsigned int.
 555  * 0 is success, < 0 is failure.
 556  */
 557
 558 static int
 559 ebml_read_uint (MatroskaDemuxContext *matroska,
 560                 uint32_t             *id,
 561                 uint64_t             *num)
 562 {
 563     ByteIOContext *pb = &matroska->ctx->pb;
 564     int n = 0, size, res;
 565     uint64_t rlength;
 566
 567     if ((res = ebml_read_element_id(matroska, id, NULL)) < 0 ||
 568         (res = ebml_read_element_length(matroska, &rlength)) < 0)
 569         return res;
 570     size = rlength;
 571     if (size < 1 || size > 8) {
 572         offset_t pos = url_ftell(pb);
 573         av_log(matroska->ctx, AV_LOG_ERROR,
 574                "Invalid uint element size %d at position %"PRId64" (0x%"PRIx64")\n",
 575                 size, pos, pos);
 576         return AVERROR_INVALIDDATA;
 577     }
 578
 579     /* big-endian ordening; build up number */
 580     *num = 0;
 581     while (n++ < size)
 582         *num = (*num << 8) | get_byte(pb);
 583
 584     return 0;
 585 }
 586
 587 /*
 588  * Read the next element as a signed int.
 589  * 0 is success, < 0 is failure.
 590  */
 591
 592 static int
 593 ebml_read_sint (MatroskaDemuxContext *matroska,
 594                 uint32_t             *id,
 595                 int64_t              *num)
 596 {
 597     ByteIOContext *pb = &matroska->ctx->pb;
 598     int size, n = 1, negative = 0, res;
 599     uint64_t rlength;
 600
 601     if ((res = ebml_read_element_id(matroska, id, NULL)) < 0 ||
 602         (res = ebml_read_element_length(matroska, &rlength)) < 0)
 603         return res;
 604     size = rlength;
 605     if (size < 1 || size > 8) {
 606         offset_t pos = url_ftell(pb);
 607         av_log(matroska->ctx, AV_LOG_ERROR,
 608                "Invalid sint element size %d at position %"PRId64" (0x%"PRIx64")\n",
 609                 size, pos, pos);
 610         return AVERROR_INVALIDDATA;
 611     }
 612     if ((*num = get_byte(pb)) & 0x80) {
 613         negative = 1;
 614         *num &= ~0x80;
 615     }
 616     while (n++ < size)
 617         *num = (*num << 8) | get_byte(pb);
 618
 619     /* make signed */
 620     if (negative)
 621         *num = *num - (1LL << ((8 * size) - 1));
 622
 623     return 0;
 624 }
 625
 626 /*
 627  * Read the next element as a float.
 628  * 0 is success, < 0 is failure.
 629  */
 630
 631 static int
 632 ebml_read_float (MatroskaDemuxContext *matroska,
 633                  uint32_t             *id,
 634                  double               *num)
 635 {
 636     ByteIOContext *pb = &matroska->ctx->pb;
 637     int size, res;
 638     uint64_t rlength;
 639
 640     if ((res = ebml_read_element_id(matroska, id, NULL)) < 0 ||
 641         (res = ebml_read_element_length(matroska, &rlength)) < 0)
 642         return res;
 643     size = rlength;
 644
 645     if (size == 4) {
 646         *num= av_int2flt(get_be32(pb));
 647     } else if(size==8){
 648         *num= av_int2dbl(get_be64(pb));
 649     } else{
 650         offset_t pos = url_ftell(pb);
 651         av_log(matroska->ctx, AV_LOG_ERROR,
 652                "Invalid float element size %d at position %"PRIu64" (0x%"PRIx64")\n",
 653                size, pos, pos);
 654         return AVERROR_INVALIDDATA;
 655     }
 656
 657     return 0;
 658 }
 659
 660 /*
 661  * Read the next element as an ASCII string.
 662  * 0 is success, < 0 is failure.
 663  */
 664
 665 static int
 666 ebml_read_ascii (MatroskaDemuxContext *matroska,
 667                  uint32_t             *id,
 668                  char                **str)
 669 {
 670     ByteIOContext *pb = &matroska->ctx->pb;
 671     int size, res;
 672     uint64_t rlength;
 673
 674     if ((res = ebml_read_element_id(matroska, id, NULL)) < 0 ||
 675         (res = ebml_read_element_length(matroska, &rlength)) < 0)
 676         return res;
 677     size = rlength;
 678
 679     /* ebml strings are usually not 0-terminated, so we allocate one
 680      * byte more, read the string and NULL-terminate it ourselves. */
 681     if (size < 0 || !(*str = av_malloc(size + 1))) {
 682         av_log(matroska->ctx, AV_LOG_ERROR, "Memory allocation failed\n");
 683         return AVERROR_NOMEM;
 684     }
 685     if (get_buffer(pb, (uint8_t *) *str, size) != size) {
 686         offset_t pos = url_ftell(pb);
 687         av_log(matroska->ctx, AV_LOG_ERROR,
 688                "Read error at pos. %"PRIu64" (0x%"PRIx64")\n", pos, pos);
 689         return AVERROR_IO;
 690     }
 691     (*str)[size] = '\0';
 692
 693     return 0;
 694 }
 695
 696 /*
 697  * Read the next element as a UTF-8 string.
 698  * 0 is success, < 0 is failure.
 699  */
 700
 701 static int
 702 ebml_read_utf8 (MatroskaDemuxContext *matroska,
 703                 uint32_t             *id,
 704                 char                **str)
 705 {
 706   return ebml_read_ascii(matroska, id, str);
 707 }
 708
 709 /*
 710  * Read the next element as a date (nanoseconds since 1/1/2000).
 711  * 0 is success, < 0 is failure.
 712  */
 713
 714 static int
 715 ebml_read_date (MatroskaDemuxContext *matroska,
 716                 uint32_t             *id,
 717                 int64_t              *date)
 718 {
 719   return ebml_read_sint(matroska, id, date);
 720 }
 721
 722 /*
 723  * Read the next element, but only the header. The contents
 724  * are supposed to be sub-elements which can be read separately.
 725  * 0 is success, < 0 is failure.
 726  */
 727
 728 static int
 729 ebml_read_master (MatroskaDemuxContext *matroska,
 730                   uint32_t             *id)
 731 {
 732     ByteIOContext *pb = &matroska->ctx->pb;
 733     uint64_t length;
 734     MatroskaLevel *level;
 735     int res;
 736
 737     if ((res = ebml_read_element_id(matroska, id, NULL)) < 0 ||
 738         (res = ebml_read_element_length(matroska, &length)) < 0)
 739         return res;
 740
 741     /* protect... (Heaven forbids that the '>' is true) */
 742     if (matroska->num_levels >= EBML_MAX_DEPTH) {
 743         av_log(matroska->ctx, AV_LOG_ERROR,
 744                "File moves beyond max. allowed depth (%d)\n", EBML_MAX_DEPTH);
 745         return AVERROR_NOTSUPP;
 746     }
 747
 748     /* remember level */
 749     level = &matroska->levels[matroska->num_levels++];
 750     level->start = url_ftell(pb);
 751     level->length = length;
 752
 753     return 0;
 754 }
 755
 756 /*
 757  * Read the next element as binary data.
 758  * 0 is success, < 0 is failure.
 759  */
 760
 761 static int
 762 ebml_read_binary (MatroskaDemuxContext *matroska,
 763                   uint32_t             *id,
 764                   uint8_t             **binary,
 765                   int                  *size)
 766 {
 767     ByteIOContext *pb = &matroska->ctx->pb;
 768     uint64_t rlength;
 769     int res;
 770
 771     if ((res = ebml_read_element_id(matroska, id, NULL)) < 0 ||
 772         (res = ebml_read_element_length(matroska, &rlength)) < 0)
 773         return res;
 774     *size = rlength;
 775
 776     if (!(*binary = av_malloc(*size))) {
 777         av_log(matroska->ctx, AV_LOG_ERROR,
 778                "Memory allocation error\n");
 779         return AVERROR_NOMEM;
 780     }
 781
 782     if (get_buffer(pb, *binary, *size) != *size) {
 783         offset_t pos = url_ftell(pb);
 784         av_log(matroska->ctx, AV_LOG_ERROR,
 785                "Read error at pos. %"PRIu64" (0x%"PRIx64")\n", pos, pos);
 786         return AVERROR_IO;
 787     }
 788
 789     return 0;
 790 }
 791
 792 /*
 793  * Read signed/unsigned "EBML" numbers.
 794  * Return: number of bytes processed, < 0 on error.
 795  * XXX: use ebml_read_num().
 796  */
 797
 798 static int
 799 matroska_ebmlnum_uint (uint8_t  *data,
 800                        uint32_t  size,
 801                        uint64_t *num)
 802 {
 803     int len_mask = 0x80, read = 1, n = 1, num_ffs = 0;
 804     uint64_t total;
 805
 806     if (size <= 0)
 807         return AVERROR_INVALIDDATA;
 808
 809     total = data[0];
 810     while (read <= 8 && !(total & len_mask)) {
 811         read++;
 812         len_mask >>= 1;
 813     }
 814     if (read > 8)
 815         return AVERROR_INVALIDDATA;
 816
 817     if ((total &= (len_mask - 1)) == len_mask - 1)
 818         num_ffs++;
 819     if (size < read)
 820         return AVERROR_INVALIDDATA;
 821     while (n < read) {
 822         if (data[n] == 0xff)
 823             num_ffs++;
 824         total = (total << 8) | data[n];
 825         n++;
 826     }
 827
 828     if (read == num_ffs)
 829         *num = (uint64_t)-1;
 830     else
 831         *num = total;
 832
 833     return read;
 834 }
 835
 836 /*
 837  * Same as above, but signed.
 838  */
 839
 840 static int
 841 matroska_ebmlnum_sint (uint8_t  *data,
 842                        uint32_t  size,
 843                        int64_t  *num)
 844 {
 845     uint64_t unum;
 846     int res;
 847
 848     /* read as unsigned number first */
 849     if ((res = matroska_ebmlnum_uint(data, size, &unum)) < 0)
 850         return res;
 851
 852     /* make signed (weird way) */
 853     if (unum == (uint64_t)-1)
 854         *num = INT64_MAX;
 855     else
 856         *num = unum - ((1LL << ((7 * res) - 1)) - 1);
 857
 858     return res;
 859 }
 860
 861 /*
 862  * Read an EBML header.
 863  * 0 is success, < 0 is failure.
 864  */
 865
 866 static int
 867 ebml_read_header (MatroskaDemuxContext *matroska,
 868                   char                **doctype,
 869                   int                  *version)
 870 {
 871     uint32_t id;
 872     int level_up, res = 0;
 873
 874     /* default init */
 875     if (doctype)
 876         *doctype = NULL;
 877     if (version)
 878         *version = 1;
 879
 880     if (!(id = ebml_peek_id(matroska, &level_up)) ||
 881         level_up != 0 || id != EBML_ID_HEADER) {
 882         av_log(matroska->ctx, AV_LOG_ERROR,
 883                "This is not an EBML file (id=0x%x/0x%x)\n", id, EBML_ID_HEADER);
 884         return AVERROR_INVALIDDATA;
 885     }
 886     if ((res = ebml_read_master(matroska, &id)) < 0)
 887         return res;
 888
 889     while (res == 0) {
 890         if (!(id = ebml_peek_id(matroska, &level_up)))
 891             return AVERROR_IO;
 892
 893         /* end-of-header */
 894         if (level_up)
 895             break;
 896
 897         switch (id) {
 898             /* is our read version uptodate? */
 899             case EBML_ID_EBMLREADVERSION: {
 900                 uint64_t num;
 901
 902                 if ((res = ebml_read_uint(matroska, &id, &num)) < 0)
 903                     return res;
 904                 if (num > EBML_VERSION) {
 905                     av_log(matroska->ctx, AV_LOG_ERROR,
 906                            "EBML version %"PRIu64" (> %d) is not supported\n",
 907                            num, EBML_VERSION);
 908                     return AVERROR_INVALIDDATA;
 909                 }
 910                 break;
 911             }
 912
 913             /* we only handle 8 byte lengths at max */
 914             case EBML_ID_EBMLMAXSIZELENGTH: {
 915                 uint64_t num;
 916
 917                 if ((res = ebml_read_uint(matroska, &id, &num)) < 0)
 918                     return res;
 919                 if (num > sizeof(uint64_t)) {
 920                     av_log(matroska->ctx, AV_LOG_ERROR,
 921                            "Integers of size %"PRIu64" (> %zd) not supported\n",
 922                            num, sizeof(uint64_t));
 923                     return AVERROR_INVALIDDATA;
 924                 }
 925                 break;
 926             }
 927
 928             /* we handle 4 byte IDs at max */
 929             case EBML_ID_EBMLMAXIDLENGTH: {
 930                 uint64_t num;
 931
 932                 if ((res = ebml_read_uint(matroska, &id, &num)) < 0)
 933                     return res;
 934                 if (num > sizeof(uint32_t)) {
 935                     av_log(matroska->ctx, AV_LOG_ERROR,
 936                            "IDs of size %"PRIu64" (> %zu) not supported\n",
 937                             num, sizeof(uint32_t));
 938                     return AVERROR_INVALIDDATA;
 939                 }
 940                 break;
 941             }
 942
 943             case EBML_ID_DOCTYPE: {
 944                 char *text;
 945
 946                 if ((res = ebml_read_ascii(matroska, &id, &text)) < 0)
 947                     return res;
 948                 if (doctype) {
 949                     if (*doctype)
 950                         av_free(*doctype);
 951                     *doctype = text;
 952                 } else
 953                     av_free(text);
 954                 break;
 955             }
 956
 957             case EBML_ID_DOCTYPEREADVERSION: {
 958                 uint64_t num;
 959
 960                 if ((res = ebml_read_uint(matroska, &id, &num)) < 0)
 961                     return res;
 962                 if (version)
 963                     *version = num;
 964                 break;
 965             }
 966
 967             default:
 968                 av_log(matroska->ctx, AV_LOG_INFO,
 969                        "Unknown data type 0x%x in EBML header", id);
 970                 /* pass-through */
 971
 972             case EBML_ID_VOID:
 973             /* we ignore these two, as they don't tell us anything we
 974              * care about */
 975             case EBML_ID_EBMLVERSION:
 976             case EBML_ID_DOCTYPEVERSION:
 977                 res = ebml_read_skip (matroska);
 978                 break;
 979         }
 980     }
 981
 982     return 0;
 983 }
 984
 985 /*
 986  * Put one packet in an application-supplied AVPacket struct.
 987  * Returns 0 on success or -1 on failure.
 988  */
 989
 990 static int
 991 matroska_deliver_packet (MatroskaDemuxContext *matroska,
 992                          AVPacket             *pkt)
 993 {
 994     if (matroska->num_packets > 0) {
 995         memcpy(pkt, matroska->packets[0], sizeof(AVPacket));
 996         av_free(matroska->packets[0]);
 997         if (matroska->num_packets > 1) {
 998             memmove(&matroska->packets[0], &matroska->packets[1],
 999                     (matroska->num_packets - 1) * sizeof(AVPacket *));
1000             matroska->packets =
1001                 av_realloc(matroska->packets, (matroska->num_packets - 1) *
1002                            sizeof(AVPacket *));
1003         } else {
1004             av_freep(&matroska->packets);
1005         }
1006         matroska->num_packets--;
1007         return 0;
1008     }
1009
1010     return -1;
1011 }
1012
1013 /*
1014  * Put a packet into our internal queue. Will be delivered to the
1015  * user/application during the next get_packet() call.
1016  */
1017
1018 static void
1019 matroska_queue_packet (MatroskaDemuxContext *matroska,
1020                        AVPacket             *pkt)
1021 {
1022     matroska->packets =
1023         av_realloc(matroska->packets, (matroska->num_packets + 1) *
1024                    sizeof(AVPacket *));
1025     matroska->packets[matroska->num_packets] = pkt;
1026     matroska->num_packets++;
1027 }
1028
1029 /*
1030  * Put a packet into our internal reordering queue. Will be moved to the
1031  * main packet queue when enough packets are available to reorder pts.
1032  */
1033
1034 static void
1035 matroska_queue_packet_reordered (MatroskaDemuxContext *matroska,
1036                                  AVPacket             *pkt,
1037                                  int                   is_bframe)
1038 {
1039     if (matroska->num_packets_reorder && !is_bframe
1040         && pkt->pts > matroska->reorder_max_pts) {
1041         /* reorder pts */
1042         int i, j, k = 1;
1043         for (j=matroska->num_packets_reorder-1; j && k; j--) {
1044             k = 0;
1045             for (i=0; i<j; i++) {
1046                 if (matroska->packets_reorder[i]->pts > matroska->packets_reorder[i+1]->pts) {
1047                     FFSWAP(uint64_t, matroska->packets_reorder[i]->pts, matroska->packets_reorder[i+1]->pts);
1048                     k = 1;
1049                 }
1050             }
1051         }
1052         /* then really queue the packets */
1053         for (i=0; i<matroska->num_packets_reorder; i++)
1054             matroska_queue_packet (matroska, matroska->packets_reorder[i]);
1055         matroska->num_packets_reorder = 0;
1056     }
1057     matroska->packets_reorder =
1058         av_realloc(matroska->packets_reorder,
1059                    (matroska->num_packets_reorder + 1) * sizeof(AVPacket *));
1060     matroska->packets_reorder[matroska->num_packets_reorder++] = pkt;
1061     if (pkt->pts > matroska->reorder_max_pts)
1062         matroska->reorder_max_pts = pkt->pts;
1063 }
1064
1065
1066 /*
1067  * Autodetecting...
1068  */
1069
1070 static int
1071 matroska_probe (AVProbeData *p)
1072 {
1073     uint64_t total = 0;
1074     int len_mask = 0x80, size = 1, n = 1;
1075     uint8_t probe_data[] = { 'm', 'a', 't', 'r', 'o', 's', 'k', 'a' };
1076
1077     if (p->buf_size < 5)
1078         return 0;
1079
1080     /* ebml header? */
1081     if ((p->buf[0] << 24 | p->buf[1] << 16 |
1082          p->buf[2] << 8 | p->buf[3]) != EBML_ID_HEADER)
1083         return 0;
1084
1085     /* length of header */
1086     total = p->buf[4];
1087     while (size <= 8 && !(total & len_mask)) {
1088         size++;
1089         len_mask >>= 1;
1090     }
1091     if (size > 8)
1092       return 0;
1093     total &= (len_mask - 1);
1094     while (n < size)
1095         total = (total << 8) | p->buf[4 + n++];
1096
1097     /* does the probe data contain the whole header? */
1098     if (p->buf_size < 4 + size + total)
1099       return 0;
1100
1101     /* the header must contain the document type 'matroska'. For now,
1102      * we don't parse the whole header but simply check for the
1103      * availability of that array of characters inside the header.
1104      * Not fully fool-proof, but good enough. */
1105     for (n = 4 + size; n <= 4 + size + total - sizeof(probe_data); n++)
1106         if (!memcmp (&p->buf[n], probe_data, sizeof(probe_data)))
1107             return AVPROBE_SCORE_MAX;
1108
1109     return 0;
1110 }
1111
1112 /*
1113  * From here on, it's all XML-style DTD stuff... Needs no comments.
1114  */
1115
1116 static int
1117 matroska_parse_info (MatroskaDemuxContext *matroska)
1118 {
1119     int res = 0;
1120     uint32_t id;
1121
1122     av_log(matroska->ctx, AV_LOG_DEBUG, "Parsing info...\n");
1123
1124     while (res == 0) {
1125         if (!(id = ebml_peek_id(matroska, &matroska->level_up))) {
1126             res = AVERROR_IO;
1127             break;
1128         } else if (matroska->level_up) {
1129             matroska->level_up--;
1130             break;
1131         }
1132
1133         switch (id) {
1134             /* cluster timecode */
1135             case MATROSKA_ID_TIMECODESCALE: {
1136                 uint64_t num;
1137                 if ((res = ebml_read_uint(matroska, &id, &num)) < 0)
1138                     break;
1139                 matroska->time_scale = num;
1140                 break;
1141             }
1142
1143             case MATROSKA_ID_DURATION: {
1144                 double num;
1145                 if ((res = ebml_read_float(matroska, &id, &num)) < 0)
1146                     break;
1147                 matroska->ctx->duration = num * matroska->time_scale * 1000 / AV_TIME_BASE;
1148                 break;
1149             }
1150
1151             case MATROSKA_ID_TITLE: {
1152                 char *text;
1153                 if ((res = ebml_read_utf8(matroska, &id, &text)) < 0)
1154                     break;
1155                 strncpy(matroska->ctx->title, text,
1156                         sizeof(matroska->ctx->title)-1);
1157                 av_free(text);
1158                 break;
1159             }
1160
1161             case MATROSKA_ID_WRITINGAPP: {
1162                 char *text;
1163                 if ((res = ebml_read_utf8(matroska, &id, &text)) < 0)
1164                     break;
1165                 matroska->writing_app = text;
1166                 break;
1167             }
1168
1169             case MATROSKA_ID_MUXINGAPP: {
1170                 char *text;
1171                 if ((res = ebml_read_utf8(matroska, &id, &text)) < 0)
1172                     break;
1173                 matroska->muxing_app = text;
1174                 break;
1175             }
1176
1177             case MATROSKA_ID_DATEUTC: {
1178                 int64_t time;
1179                 if ((res = ebml_read_date(matroska, &id, &time)) < 0)
1180                     break;
1181                 matroska->created = time;
1182                 break;
1183             }
1184
1185             default:
1186                 av_log(matroska->ctx, AV_LOG_INFO,
1187                        "Unknown entry 0x%x in info header\n", id);
1188                 /* fall-through */
1189
1190             case EBML_ID_VOID:
1191                 res = ebml_read_skip(matroska);
1192                 break;
1193         }
1194
1195         if (matroska->level_up) {
1196             matroska->level_up--;
1197             break;
1198         }
1199     }
1200
1201     return res;
1202 }
1203
1204 static int
1205 matroska_add_stream (MatroskaDemuxContext *matroska)
1206 {
1207     int res = 0;
1208     uint32_t id;
1209     MatroskaTrack *track;
1210
1211     av_log(matroska->ctx, AV_LOG_DEBUG, "parsing track, adding stream..,\n");
1212
1213     /* Allocate a generic track. As soon as we know its type we'll realloc. */
1214     track = av_mallocz(MAX_TRACK_SIZE);
1215     matroska->num_tracks++;
1216
1217     /* start with the master */
1218     if ((res = ebml_read_master(matroska, &id)) < 0)
1219         return res;
1220
1221     /* try reading the trackentry headers */
1222     while (res == 0) {
1223         if (!(id = ebml_peek_id(matroska, &matroska->level_up))) {
1224             res = AVERROR_IO;
1225             break;
1226         } else if (matroska->level_up > 0) {
1227             matroska->level_up--;
1228             break;
1229         }
1230
1231         switch (id) {
1232             /* track number (unique stream ID) */
1233             case MATROSKA_ID_TRACKNUMBER: {
1234                 uint64_t num;
1235                 if ((res = ebml_read_uint(matroska, &id, &num)) < 0)
1236                     break;
1237                 track->num = num;
1238                 break;
1239             }
1240
1241             /* track UID (unique identifier) */
1242             case MATROSKA_ID_TRACKUID: {
1243                 uint64_t num;
1244                 if ((res = ebml_read_uint(matroska, &id, &num)) < 0)
1245                     break;
1246                 track->uid = num;
1247                 break;
1248             }
1249
1250             /* track type (video, audio, combined, subtitle, etc.) */
1251             case MATROSKA_ID_TRACKTYPE: {
1252                 uint64_t num;
1253                 if ((res = ebml_read_uint(matroska, &id, &num)) < 0)
1254                     break;
1255                 if (track->type && track->type != num) {
1256                     av_log(matroska->ctx, AV_LOG_INFO,
1257                            "More than one tracktype in an entry - skip\n");
1258                     break;
1259                 }
1260                 track->type = num;
1261
1262                 switch (track->type) {
1263                     case MATROSKA_TRACK_TYPE_VIDEO:
1264                     case MATROSKA_TRACK_TYPE_AUDIO:
1265                     case MATROSKA_TRACK_TYPE_SUBTITLE:
1266                         break;
1267                     case MATROSKA_TRACK_TYPE_COMPLEX:
1268                     case MATROSKA_TRACK_TYPE_LOGO:
1269                     case MATROSKA_TRACK_TYPE_CONTROL:
1270                     default:
1271                         av_log(matroska->ctx, AV_LOG_INFO,
1272                                "Unknown or unsupported track type 0x%x\n",
1273                                track->type);
1274                         track->type = 0;
1275                         break;
1276                 }
1277                 matroska->tracks[matroska->num_tracks - 1] = track;
1278                 break;
1279             }
1280
1281             /* tracktype specific stuff for video */
1282             case MATROSKA_ID_TRACKVIDEO: {
1283                 MatroskaVideoTrack *videotrack;
1284                 if (!track->type)
1285                     track->type = MATROSKA_TRACK_TYPE_VIDEO;
1286                 if (track->type != MATROSKA_TRACK_TYPE_VIDEO) {
1287                     av_log(matroska->ctx, AV_LOG_INFO,
1288                            "video data in non-video track - ignoring\n");
1289                     res = AVERROR_INVALIDDATA;
1290                     break;
1291                 } else if ((res = ebml_read_master(matroska, &id)) < 0)
1292                     break;
1293                 videotrack = (MatroskaVideoTrack *)track;
1294
1295                 while (res == 0) {
1296                     if (!(id = ebml_peek_id(matroska, &matroska->level_up))) {
1297                         res = AVERROR_IO;
1298                         break;
1299                     } else if (matroska->level_up > 0) {
1300                         matroska->level_up--;
1301                         break;
1302                     }
1303
1304                     switch (id) {
1305                         /* fixme, this should be one-up, but I get it here */
1306                         case MATROSKA_ID_TRACKDEFAULTDURATION: {
1307                             uint64_t num;
1308                             if ((res = ebml_read_uint (matroska, &id,
1309                                                        &num)) < 0)
1310                                 break;
1311                             track->default_duration = num/matroska->time_scale;
1312                             break;
1313                         }
1314
1315                         /* video framerate */
1316                         case MATROSKA_ID_VIDEOFRAMERATE: {
1317                             double num;
1318                             if ((res = ebml_read_float(matroska, &id,
1319                                                        &num)) < 0)
1320                                 break;
1321                             track->default_duration = 1000000000/(matroska->time_scale*num);
1322                             break;
1323                         }
1324
1325                         /* width of the size to display the video at */
1326                         case MATROSKA_ID_VIDEODISPLAYWIDTH: {
1327                             uint64_t num;
1328                             if ((res = ebml_read_uint(matroska, &id,
1329                                                       &num)) < 0)
1330                                 break;
1331                             videotrack->display_width = num;
1332                             break;
1333                         }
1334
1335                         /* height of the size to display the video at */
1336                         case MATROSKA_ID_VIDEODISPLAYHEIGHT: {
1337                             uint64_t num;
1338                             if ((res = ebml_read_uint(matroska, &id,
1339                                                       &num)) < 0)
1340                                 break;
1341                             videotrack->display_height = num;
1342                             break;
1343                         }
1344
1345                         /* width of the video in the file */
1346                         case MATROSKA_ID_VIDEOPIXELWIDTH: {
1347                             uint64_t num;
1348                             if ((res = ebml_read_uint(matroska, &id,
1349                                                       &num)) < 0)
1350                                 break;
1351                             videotrack->pixel_width = num;
1352                             break;
1353                         }
1354
1355                         /* height of the video in the file */
1356                         case MATROSKA_ID_VIDEOPIXELHEIGHT: {
1357                             uint64_t num;
1358                             if ((res = ebml_read_uint(matroska, &id,
1359                                                       &num)) < 0)
1360                                 break;
1361                             videotrack->pixel_height = num;
1362                             break;
1363                         }
1364
1365                         /* whether the video is interlaced */
1366                         case MATROSKA_ID_VIDEOFLAGINTERLACED: {
1367                             uint64_t num;
1368                             if ((res = ebml_read_uint(matroska, &id,
1369                                                       &num)) < 0)
1370                                 break;
1371                             if (num)
1372                                 track->flags |=
1373                                     MATROSKA_VIDEOTRACK_INTERLACED;
1374                             else
1375                                 track->flags &=
1376                                     ~MATROSKA_VIDEOTRACK_INTERLACED;
1377                             break;
1378                         }
1379
1380                         /* stereo mode (whether the video has two streams,
1381                          * where one is for the left eye and the other for
1382                          * the right eye, which creates a 3D-like
1383                          * effect) */
1384                         case MATROSKA_ID_VIDEOSTEREOMODE: {
1385                             uint64_t num;
1386                             if ((res = ebml_read_uint(matroska, &id,
1387                                                       &num)) < 0)
1388                                 break;
1389                             if (num != MATROSKA_EYE_MODE_MONO &&
1390                                 num != MATROSKA_EYE_MODE_LEFT &&
1391                                 num != MATROSKA_EYE_MODE_RIGHT &&
1392                                 num != MATROSKA_EYE_MODE_BOTH) {
1393                                 av_log(matroska->ctx, AV_LOG_INFO,
1394                                        "Ignoring unknown eye mode 0x%x\n",
1395                                        (uint32_t) num);
1396                                 break;
1397                             }
1398                             videotrack->eye_mode = num;
1399                             break;
1400                         }
1401
1402                         /* aspect ratio behaviour */
1403                         case MATROSKA_ID_VIDEOASPECTRATIO: {
1404                             uint64_t num;
1405                             if ((res = ebml_read_uint(matroska, &id,
1406                                                       &num)) < 0)
1407                                 break;
1408                             if (num != MATROSKA_ASPECT_RATIO_MODE_FREE &&
1409                                 num != MATROSKA_ASPECT_RATIO_MODE_KEEP &&
1410                                 num != MATROSKA_ASPECT_RATIO_MODE_FIXED) {
1411                                 av_log(matroska->ctx, AV_LOG_INFO,
1412                                        "Ignoring unknown aspect ratio 0x%x\n",
1413                                        (uint32_t) num);
1414                                 break;
1415                             }
1416                             videotrack->ar_mode = num;
1417                             break;
1418                         }
1419
1420                         /* colourspace (only matters for raw video)
1421                          * fourcc */
1422                         case MATROSKA_ID_VIDEOCOLOURSPACE: {
1423                             uint64_t num;
1424                             if ((res = ebml_read_uint(matroska, &id,
1425                                                       &num)) < 0)
1426                                 break;
1427                             videotrack->fourcc = num;
1428                             break;
1429                         }
1430
1431                         default:
1432                             av_log(matroska->ctx, AV_LOG_INFO,
1433                                    "Unknown video track header entry "
1434                                    "0x%x - ignoring\n", id);
1435                             /* pass-through */
1436
1437                         case EBML_ID_VOID:
1438                             res = ebml_read_skip(matroska);
1439                             break;
1440                     }
1441
1442                     if (matroska->level_up) {
1443                         matroska->level_up--;
1444                         break;
1445                     }
1446                 }
1447                 break;
1448             }
1449
1450             /* tracktype specific stuff for audio */
1451             case MATROSKA_ID_TRACKAUDIO: {
1452                 MatroskaAudioTrack *audiotrack;
1453                 if (!track->type)
1454                     track->type = MATROSKA_TRACK_TYPE_AUDIO;
1455                 if (track->type != MATROSKA_TRACK_TYPE_AUDIO) {
1456                     av_log(matroska->ctx, AV_LOG_INFO,
1457                            "audio data in non-audio track - ignoring\n");
1458                     res = AVERROR_INVALIDDATA;
1459                     break;
1460                 } else if ((res = ebml_read_master(matroska, &id)) < 0)
1461                     break;
1462                 audiotrack = (MatroskaAudioTrack *)track;
1463                 audiotrack->channels = 1;
1464                 audiotrack->samplerate = 8000;
1465
1466                 while (res == 0) {
1467                     if (!(id = ebml_peek_id(matroska, &matroska->level_up))) {
1468                         res = AVERROR_IO;
1469                         break;
1470                     } else if (matroska->level_up > 0) {
1471                         matroska->level_up--;
1472                         break;
1473                     }
1474
1475                     switch (id) {
1476                         /* samplerate */
1477                         case MATROSKA_ID_AUDIOSAMPLINGFREQ: {
1478                             double num;
1479                             if ((res = ebml_read_float(matroska, &id,
1480                                                        &num)) < 0)
1481                                 break;
1482                             audiotrack->internal_samplerate =
1483                             audiotrack->samplerate = num;
1484                             break;
1485                         }
1486
1487                         case MATROSKA_ID_AUDIOOUTSAMPLINGFREQ: {
1488                             double num;
1489                             if ((res = ebml_read_float(matroska, &id,
1490                                                        &num)) < 0)
1491                                 break;
1492                             audiotrack->samplerate = num;
1493                             break;
1494                         }
1495
1496                             /* bitdepth */
1497                         case MATROSKA_ID_AUDIOBITDEPTH: {
1498                             uint64_t num;
1499                             if ((res = ebml_read_uint(matroska, &id,
1500                                                       &num)) < 0)
1501                                 break;
1502                             audiotrack->bitdepth = num;
1503                             break;
1504                         }
1505
1506                             /* channels */
1507                         case MATROSKA_ID_AUDIOCHANNELS: {
1508                             uint64_t num;
1509                             if ((res = ebml_read_uint(matroska, &id,
1510                                                       &num)) < 0)
1511                                 break;
1512                             audiotrack->channels = num;
1513                             break;
1514                         }
1515
1516                         default:
1517                             av_log(matroska->ctx, AV_LOG_INFO,
1518                                    "Unknown audio track header entry "
1519                                    "0x%x - ignoring\n", id);
1520                             /* pass-through */
1521
1522                         case EBML_ID_VOID:
1523                             res = ebml_read_skip(matroska);
1524                             break;
1525                     }
1526
1527                     if (matroska->level_up) {
1528                         matroska->level_up--;
1529                         break;
1530                     }
1531                 }
1532                 break;
1533             }
1534
1535                 /* codec identifier */
1536             case MATROSKA_ID_CODECID: {
1537                 char *text;
1538                 if ((res = ebml_read_ascii(matroska, &id, &text)) < 0)
1539                     break;
1540                 track->codec_id = text;
1541                 break;
1542             }
1543
1544                 /* codec private data */
1545             case MATROSKA_ID_CODECPRIVATE: {
1546                 uint8_t *data;
1547                 int size;
1548                 if ((res = ebml_read_binary(matroska, &id, &data, &size) < 0))
1549                     break;
1550                 track->codec_priv = data;
1551                 track->codec_priv_size = size;
1552                 break;
1553             }
1554
1555                 /* name of the codec */
1556             case MATROSKA_ID_CODECNAME: {
1557                 char *text;
1558                 if ((res = ebml_read_utf8(matroska, &id, &text)) < 0)
1559                     break;
1560                 track->codec_name = text;
1561                 break;
1562             }
1563
1564                 /* name of this track */
1565             case MATROSKA_ID_TRACKNAME: {
1566                 char *text;
1567                 if ((res = ebml_read_utf8(matroska, &id, &text)) < 0)
1568                     break;
1569                 track->name = text;
1570                 break;
1571             }
1572
1573                 /* language (matters for audio/subtitles, mostly) */
1574             case MATROSKA_ID_TRACKLANGUAGE: {
1575                 char *text;
1576                 if ((res = ebml_read_utf8(matroska, &id, &text)) < 0)
1577                     break;
1578                 track->language = text;
1579                 break;
1580             }
1581
1582                 /* whether this is actually used */
1583             case MATROSKA_ID_TRACKFLAGENABLED: {
1584                 uint64_t num;
1585                 if ((res = ebml_read_uint(matroska, &id, &num)) < 0)
1586                     break;
1587                 if (num)
1588                     track->flags |= MATROSKA_TRACK_ENABLED;
1589                 else
1590                     track->flags &= ~MATROSKA_TRACK_ENABLED;
1591                 break;
1592             }
1593
1594                 /* whether it's the default for this track type */
1595             case MATROSKA_ID_TRACKFLAGDEFAULT: {
1596                 uint64_t num;
1597                 if ((res = ebml_read_uint(matroska, &id, &num)) < 0)
1598                     break;
1599                 if (num)
1600                     track->flags |= MATROSKA_TRACK_DEFAULT;
1601                 else
1602                     track->flags &= ~MATROSKA_TRACK_DEFAULT;
1603                 break;
1604             }
1605
1606                 /* lacing (like MPEG, where blocks don't end/start on frame
1607                  * boundaries) */
1608             case MATROSKA_ID_TRACKFLAGLACING: {
1609                 uint64_t num;
1610                 if ((res = ebml_read_uint(matroska, &id, &num)) < 0)
1611                     break;
1612                 if (num)
1613                     track->flags |= MATROSKA_TRACK_LACING;
1614                 else
1615                     track->flags &= ~MATROSKA_TRACK_LACING;
1616                 break;
1617             }
1618
1619                 /* default length (in time) of one data block in this track */
1620             case MATROSKA_ID_TRACKDEFAULTDURATION: {
1621                 uint64_t num;
1622                 if ((res = ebml_read_uint(matroska, &id, &num)) < 0)
1623                     break;
1624                 track->default_duration = num / matroska->time_scale;
1625                 break;
1626             }
1627
1628             default:
1629                 av_log(matroska->ctx, AV_LOG_INFO,
1630                        "Unknown track header entry 0x%x - ignoring\n", id);
1631                 /* pass-through */
1632
1633             case EBML_ID_VOID:
1634             /* we ignore these because they're nothing useful. */
1635             case MATROSKA_ID_CODECINFOURL:
1636             case MATROSKA_ID_CODECDOWNLOADURL:
1637             case MATROSKA_ID_TRACKMINCACHE:
1638             case MATROSKA_ID_TRACKMAXCACHE:
1639                 res = ebml_read_skip(matroska);
1640                 break;
1641         }
1642
1643         if (matroska->level_up) {
1644             matroska->level_up--;
1645             break;
1646         }
1647     }
1648
1649     return res;
1650 }
1651
1652 static int
1653 matroska_parse_tracks (MatroskaDemuxContext *matroska)
1654 {
1655     int res = 0;
1656     uint32_t id;
1657
1658     av_log(matroska->ctx, AV_LOG_DEBUG, "parsing tracks...\n");
1659
1660     while (res == 0) {
1661         if (!(id = ebml_peek_id(matroska, &matroska->level_up))) {
1662             res = AVERROR_IO;
1663             break;
1664         } else if (matroska->level_up) {
1665             matroska->level_up--;
1666             break;
1667         }
1668
1669         switch (id) {
1670             /* one track within the "all-tracks" header */
1671             case MATROSKA_ID_TRACKENTRY:
1672                 res = matroska_add_stream(matroska);
1673                 break;
1674
1675             default:
1676                 av_log(matroska->ctx, AV_LOG_INFO,
1677                        "Unknown entry 0x%x in track header\n", id);
1678                 /* fall-through */
1679
1680             case EBML_ID_VOID:
1681                 res = ebml_read_skip(matroska);
1682                 break;
1683         }
1684
1685         if (matroska->level_up) {
1686             matroska->level_up--;
1687             break;
1688         }
1689     }
1690
1691     return res;
1692 }
1693
1694 static int
1695 matroska_parse_index (MatroskaDemuxContext *matroska)
1696 {
1697     int res = 0;
1698     uint32_t id;
1699     MatroskaDemuxIndex idx;
1700
1701     av_log(matroska->ctx, AV_LOG_DEBUG, "parsing index...\n");
1702
1703     while (res == 0) {
1704         if (!(id = ebml_peek_id(matroska, &matroska->level_up))) {
1705             res = AVERROR_IO;
1706             break;
1707         } else if (matroska->level_up) {
1708             matroska->level_up--;
1709             break;
1710         }
1711
1712         switch (id) {
1713             /* one single index entry ('point') */
1714             case MATROSKA_ID_POINTENTRY:
1715                 if ((res = ebml_read_master(matroska, &id)) < 0)
1716                     break;
1717
1718                 /* in the end, we hope to fill one entry with a
1719                  * timestamp, a file position and a tracknum */
1720                 idx.pos   = (uint64_t) -1;
1721                 idx.time  = (uint64_t) -1;
1722                 idx.track = (uint16_t) -1;
1723
1724                 while (res == 0) {
1725                     if (!(id = ebml_peek_id(matroska, &matroska->level_up))) {
1726                         res = AVERROR_IO;
1727                         break;
1728                     } else if (matroska->level_up) {
1729                         matroska->level_up--;
1730                         break;
1731                     }
1732
1733                     switch (id) {
1734                         /* one single index entry ('point') */
1735                         case MATROSKA_ID_CUETIME: {
1736                             uint64_t time;
1737                             if ((res = ebml_read_uint(matroska, &id,
1738                                                       &time)) < 0)
1739                                 break;
1740                             idx.time = time * matroska->time_scale;
1741                             break;
1742                         }
1743
1744                         /* position in the file + track to which it
1745                          * belongs */
1746                         case MATROSKA_ID_CUETRACKPOSITION:
1747                             if ((res = ebml_read_master(matroska, &id)) < 0)
1748                                 break;
1749
1750                             while (res == 0) {
1751                                 if (!(id = ebml_peek_id (matroska,
1752                                                     &matroska->level_up))) {
1753                                     res = AVERROR_IO;
1754                                     break;
1755                                 } else if (matroska->level_up) {
1756                                     matroska->level_up--;
1757                                     break;
1758                                 }
1759
1760                                 switch (id) {
1761                                     /* track number */
1762                                     case MATROSKA_ID_CUETRACK: {
1763                                         uint64_t num;
1764                                         if ((res = ebml_read_uint(matroska,
1765                                                           &id, &num)) < 0)
1766                                             break;
1767                                         idx.track = num;
1768                                         break;
1769                                     }
1770
1771                                         /* position in file */
1772                                     case MATROSKA_ID_CUECLUSTERPOSITION: {
1773                                         uint64_t num;
1774                                         if ((res = ebml_read_uint(matroska,
1775                                                           &id, &num)) < 0)
1776                                             break;
1777                                         idx.pos = num;
1778                                         break;
1779                                     }
1780
1781                                     default:
1782                                         av_log(matroska->ctx, AV_LOG_INFO,
1783                                                "Unknown entry 0x%x in "
1784                                                "CuesTrackPositions\n", id);
1785                                         /* fall-through */
1786
1787                                     case EBML_ID_VOID:
1788                                         res = ebml_read_skip(matroska);
1789                                         break;
1790                                 }
1791
1792                                 if (matroska->level_up) {
1793                                     matroska->level_up--;
1794                                     break;
1795                                 }
1796                             }
1797
1798                             break;
1799
1800                         default:
1801                             av_log(matroska->ctx, AV_LOG_INFO,
1802                                    "Unknown entry 0x%x in cuespoint "
1803                                    "index\n", id);
1804                             /* fall-through */
1805
1806                         case EBML_ID_VOID:
1807                             res = ebml_read_skip(matroska);
1808                             break;
1809                     }
1810
1811                     if (matroska->level_up) {
1812                         matroska->level_up--;
1813                         break;
1814                     }
1815                 }
1816
1817                 /* so let's see if we got what we wanted */
1818                 if (idx.pos   != (uint64_t) -1 &&
1819                     idx.time  != (uint64_t) -1 &&
1820                     idx.track != (uint16_t) -1) {
1821                     if (matroska->num_indexes % 32 == 0) {
1822                         /* re-allocate bigger index */
1823                         matroska->index =
1824                             av_realloc(matroska->index,
1825                                        (matroska->num_indexes + 32) *
1826                                        sizeof(MatroskaDemuxIndex));
1827                     }
1828                     matroska->index[matroska->num_indexes] = idx;
1829                     matroska->num_indexes++;
1830                 }
1831                 break;
1832
1833             default:
1834                 av_log(matroska->ctx, AV_LOG_INFO,
1835                        "Unknown entry 0x%x in cues header\n", id);
1836                 /* fall-through */
1837
1838             case EBML_ID_VOID:
1839                 res = ebml_read_skip(matroska);
1840                 break;
1841         }
1842
1843         if (matroska->level_up) {
1844             matroska->level_up--;
1845             break;
1846         }
1847     }
1848
1849     return res;
1850 }
1851
1852 static int
1853 matroska_parse_metadata (MatroskaDemuxContext *matroska)
1854 {
1855     int res = 0;
1856     uint32_t id;
1857
1858     while (res == 0) {
1859         if (!(id = ebml_peek_id(matroska, &matroska->level_up))) {
1860             res = AVERROR_IO;
1861             break;
1862         } else if (matroska->level_up) {
1863             matroska->level_up--;
1864             break;
1865         }
1866
1867         switch (id) {
1868             /* Hm, this is unsupported... */
1869             default:
1870                 av_log(matroska->ctx, AV_LOG_INFO,
1871                        "Unknown entry 0x%x in metadata header\n", id);
1872                 /* fall-through */
1873
1874             case EBML_ID_VOID:
1875                 res = ebml_read_skip(matroska);
1876                 break;
1877         }
1878
1879         if (matroska->level_up) {
1880             matroska->level_up--;
1881             break;
1882         }
1883     }
1884
1885     return res;
1886 }
1887
1888 static int
1889 matroska_parse_seekhead (MatroskaDemuxContext *matroska)
1890 {
1891     int res = 0;
1892     uint32_t id;
1893
1894     av_log(matroska->ctx, AV_LOG_DEBUG, "parsing seekhead...\n");
1895
1896     while (res == 0) {
1897         if (!(id = ebml_peek_id(matroska, &matroska->level_up))) {
1898             res = AVERROR_IO;
1899             break;
1900         } else if (matroska->level_up) {
1901             matroska->level_up--;
1902             break;
1903         }
1904
1905         switch (id) {
1906             case MATROSKA_ID_SEEKENTRY: {
1907                 uint32_t seek_id = 0, peek_id_cache = 0;
1908                 uint64_t seek_pos = (uint64_t) -1, t;
1909
1910                 if ((res = ebml_read_master(matroska, &id)) < 0)
1911                     break;
1912
1913                 while (res == 0) {
1914                     if (!(id = ebml_peek_id(matroska, &matroska->level_up))) {
1915                         res = AVERROR_IO;
1916                         break;
1917                     } else if (matroska->level_up) {
1918                         matroska->level_up--;
1919                         break;
1920                     }
1921
1922                     switch (id) {
1923                         case MATROSKA_ID_SEEKID:
1924                             res = ebml_read_uint(matroska, &id, &t);
1925                             seek_id = t;
1926                             break;
1927
1928                         case MATROSKA_ID_SEEKPOSITION:
1929                             res = ebml_read_uint(matroska, &id, &seek_pos);
1930                             break;
1931
1932                         default:
1933                             av_log(matroska->ctx, AV_LOG_INFO,
1934                                    "Unknown seekhead ID 0x%x\n", id);
1935                             /* fall-through */
1936
1937                         case EBML_ID_VOID:
1938                             res = ebml_read_skip(matroska);
1939                             break;
1940                     }
1941
1942                     if (matroska->level_up) {
1943                         matroska->level_up--;
1944                         break;
1945                     }
1946                 }
1947
1948                 if (!seek_id || seek_pos == (uint64_t) -1) {
1949                     av_log(matroska->ctx, AV_LOG_INFO,
1950                            "Incomplete seekhead entry (0x%x/%"PRIu64")\n",
1951                            seek_id, seek_pos);
1952                     break;
1953                 }
1954
1955                 switch (seek_id) {
1956                     case MATROSKA_ID_CUES:
1957                     case MATROSKA_ID_TAGS: {
1958                         uint32_t level_up = matroska->level_up;
1959                         offset_t before_pos;
1960                         uint64_t length;
1961                         MatroskaLevel level;
1962
1963                         /* remember the peeked ID and the current position */
1964                         peek_id_cache = matroska->peek_id;
1965                         before_pos = url_ftell(&matroska->ctx->pb);
1966
1967                         /* seek */
1968                         if ((res = ebml_read_seek(matroska, seek_pos +
1969                                                matroska->segment_start)) < 0)
1970                             return res;
1971
1972                         /* we don't want to lose our seekhead level, so we add
1973                          * a dummy. This is a crude hack. */
1974                         if (matroska->num_levels == EBML_MAX_DEPTH) {
1975                             av_log(matroska->ctx, AV_LOG_INFO,
1976                                    "Max EBML element depth (%d) reached, "
1977                                    "cannot parse further.\n", EBML_MAX_DEPTH);
1978                             return AVERROR_UNKNOWN;
1979                         }
1980
1981                         level.start = 0;
1982                         level.length = (uint64_t)-1;
1983                         matroska->levels[matroska->num_levels] = level;
1984                         matroska->num_levels++;
1985
1986                         /* check ID */
1987                         if (!(id = ebml_peek_id (matroska,
1988                                                  &matroska->level_up)))
1989                             goto finish;
1990                         if (id != seek_id) {
1991                             av_log(matroska->ctx, AV_LOG_INFO,
1992                                    "We looked for ID=0x%x but got "
1993                                    "ID=0x%x (pos=%"PRIu64")",
1994                                    seek_id, id, seek_pos +
1995                                    matroska->segment_start);
1996                             goto finish;
1997                         }
1998
1999                         /* read master + parse */
2000                         if ((res = ebml_read_master(matroska, &id)) < 0)
2001                             goto finish;
2002                         switch (id) {
2003                             case MATROSKA_ID_CUES:
2004                                 if (!(res = matroska_parse_index(matroska)) ||
2005                                     url_feof(&matroska->ctx->pb)) {
2006                                     matroska->index_parsed = 1;
2007                                     res = 0;
2008                                 }
2009                                 break;
2010                             case MATROSKA_ID_TAGS:
2011                                 if (!(res = matroska_parse_metadata(matroska)) ||
2012                                    url_feof(&matroska->ctx->pb)) {
2013                                     matroska->metadata_parsed = 1;
2014                                     res = 0;
2015                                 }
2016                                 break;
2017                         }
2018
2019                     finish:
2020                         /* remove dummy level */
2021                         while (matroska->num_levels) {
2022                             matroska->num_levels--;
2023                             length =
2024                                 matroska->levels[matroska->num_levels].length;
2025                             if (length == (uint64_t)-1)
2026                                 break;
2027                         }
2028
2029                         /* seek back */
2030                         if ((res = ebml_read_seek(matroska, before_pos)) < 0)
2031                             return res;
2032                         matroska->peek_id = peek_id_cache;
2033                         matroska->level_up = level_up;
2034                         break;
2035                     }
2036
2037                     default:
2038                         av_log(matroska->ctx, AV_LOG_INFO,
2039                                "Ignoring seekhead entry for ID=0x%x\n",
2040                                seek_id);
2041                         break;
2042                 }
2043
2044                 break;
2045             }
2046
2047             default:
2048                 av_log(matroska->ctx, AV_LOG_INFO,
2049                        "Unknown seekhead ID 0x%x\n", id);
2050                 /* fall-through */
2051
2052             case EBML_ID_VOID:
2053                 res = ebml_read_skip(matroska);
2054                 break;
2055         }
2056
2057         if (matroska->level_up) {
2058             matroska->level_up--;
2059             break;
2060         }
2061     }
2062
2063     return res;
2064 }
2065
2066 #define ARRAY_SIZE(x)  (sizeof(x)/sizeof(*x))
2067
2068 static int
2069 matroska_aac_profile (char *codec_id)
2070 {
2071     static const char *aac_profiles[] = {
2072         "MAIN", "LC", "SSR"
2073     };
2074     int profile;
2075
2076     for (profile=0; profile<ARRAY_SIZE(aac_profiles); profile++)
2077         if (strstr(codec_id, aac_profiles[profile]))
2078             break;
2079     return profile + 1;
2080 }
2081
2082 static int
2083 matroska_aac_sri (int samplerate)
2084 {
2085     static const int aac_sample_rates[] = {
2086         96000, 88200, 64000, 48000, 44100, 32000,
2087         24000, 22050, 16000, 12000, 11025,  8000,
2088     };
2089     int sri;
2090
2091     for (sri=0; sri<ARRAY_SIZE(aac_sample_rates); sri++)
2092         if (aac_sample_rates[sri] == samplerate)
2093             break;
2094     return sri;
2095 }
2096
2097 static int
2098 matroska_read_header (AVFormatContext    *s,
2099                       AVFormatParameters *ap)
2100 {
2101     MatroskaDemuxContext *matroska = s->priv_data;
2102     char *doctype;
2103     int version, last_level, res = 0;
2104     uint32_t id;
2105
2106     matroska->ctx = s;
2107
2108     /* First read the EBML header. */
2109     doctype = NULL;
2110     if ((res = ebml_read_header(matroska, &doctype, &version)) < 0)
2111         return res;
2112     if ((doctype == NULL) || strcmp(doctype, "matroska")) {
2113         av_log(matroska->ctx, AV_LOG_ERROR,
2114                "Wrong EBML doctype ('%s' != 'matroska').\n",
2115                doctype ? doctype : "(none)");
2116         if (doctype)
2117             av_free(doctype);
2118         return AVERROR_NOFMT;
2119     }
2120     av_free(doctype);
2121     if (version > 2) {
2122         av_log(matroska->ctx, AV_LOG_ERROR,
2123                "Matroska demuxer version 2 too old for file version %d\n",
2124                version);
2125         return AVERROR_NOFMT;
2126     }
2127
2128     /* The next thing is a segment. */
2129     while (1) {
2130         if (!(id = ebml_peek_id(matroska, &last_level)))
2131             return AVERROR_IO;
2132         if (id == MATROSKA_ID_SEGMENT)
2133             break;
2134
2135         /* oi! */
2136         av_log(matroska->ctx, AV_LOG_INFO,
2137                "Expected a Segment ID (0x%x), but received 0x%x!\n",
2138                MATROSKA_ID_SEGMENT, id);
2139         if ((res = ebml_read_skip(matroska)) < 0)
2140             return res;
2141     }
2142
2143     /* We now have a Matroska segment.
2144      * Seeks are from the beginning of the segment,
2145      * after the segment ID/length. */
2146     if ((res = ebml_read_master(matroska, &id)) < 0)
2147         return res;
2148     matroska->segment_start = url_ftell(&s->pb);
2149
2150     matroska->time_scale = 1000000;
2151     /* we've found our segment, start reading the different contents in here */
2152     while (res == 0) {
2153         if (!(id = ebml_peek_id(matroska, &matroska->level_up))) {
2154             res = AVERROR_IO;
2155             break;
2156         } else if (matroska->level_up) {
2157             matroska->level_up--;
2158             break;
2159         }
2160
2161         switch (id) {
2162             /* stream info */
2163             case MATROSKA_ID_INFO: {
2164                 if ((res = ebml_read_master(matroska, &id)) < 0)
2165                     break;
2166                 res = matroska_parse_info(matroska);
2167                 break;
2168             }
2169
2170             /* track info headers */
2171             case MATROSKA_ID_TRACKS: {
2172                 if ((res = ebml_read_master(matroska, &id)) < 0)
2173                     break;
2174                 res = matroska_parse_tracks(matroska);
2175                 break;
2176             }
2177
2178             /* stream index */
2179             case MATROSKA_ID_CUES: {
2180                 if (!matroska->index_parsed) {
2181                     if ((res = ebml_read_master(matroska, &id)) < 0)
2182                         break;
2183                     res = matroska_parse_index(matroska);
2184                 } else
2185                     res = ebml_read_skip(matroska);
2186                 break;
2187             }
2188
2189             /* metadata */
2190             case MATROSKA_ID_TAGS: {
2191                 if (!matroska->metadata_parsed) {
2192                     if ((res = ebml_read_master(matroska, &id)) < 0)
2193                         break;
2194                     res = matroska_parse_metadata(matroska);
2195                 } else
2196                     res = ebml_read_skip(matroska);
2197                 break;
2198             }
2199
2200             /* file index (if seekable, seek to Cues/Tags to parse it) */
2201             case MATROSKA_ID_SEEKHEAD: {
2202                 if ((res = ebml_read_master(matroska, &id)) < 0)
2203                     break;
2204                 res = matroska_parse_seekhead(matroska);
2205                 break;
2206             }
2207
2208             case MATROSKA_ID_CLUSTER: {
2209                 /* Do not read the master - this will be done in the next
2210                  * call to matroska_read_packet. */
2211                 res = 1;
2212                 break;
2213             }
2214
2215             default:
2216                 av_log(matroska->ctx, AV_LOG_INFO,
2217                        "Unknown matroska file header ID 0x%x\n", id);
2218             /* fall-through */
2219
2220             case EBML_ID_VOID:
2221                 res = ebml_read_skip(matroska);
2222                 break;
2223         }
2224
2225         if (matroska->level_up) {
2226             matroska->level_up--;
2227             break;
2228         }
2229     }
2230
2231     /* Have we found a cluster? */
2232     if (ebml_peek_id(matroska, NULL) == MATROSKA_ID_CLUSTER) {
2233         int i, j;
2234         MatroskaTrack *track;
2235         AVStream *st;
2236
2237         for (i = 0; i < matroska->num_tracks; i++) {
2238             enum CodecID codec_id = CODEC_ID_NONE;
2239             uint8_t *extradata = NULL;
2240             int extradata_size = 0;
2241             int extradata_offset = 0;
2242             track = matroska->tracks[i];
2243
2244             /* libavformat does not really support subtitles.
2245              * Also apply some sanity checks. */
2246             if ((track->type == MATROSKA_TRACK_TYPE_SUBTITLE) ||
2247                 (track->codec_id == NULL))
2248                 continue;
2249
2250             for(j=0; codec_tags[j].str; j++){
2251                 if(!strncmp(codec_tags[j].str, track->codec_id,
2252                             strlen(codec_tags[j].str))){
2253                     codec_id= codec_tags[j].id;
2254                     break;
2255                 }
2256             }
2257
2258             /* Set the FourCC from the CodecID. */
2259             /* This is the MS compatibility mode which stores a
2260              * BITMAPINFOHEADER in the CodecPrivate. */
2261             if (!strcmp(track->codec_id,
2262                         MATROSKA_CODEC_ID_VIDEO_VFW_FOURCC) &&
2263                 (track->codec_priv_size >= 40) &&
2264                 (track->codec_priv != NULL)) {
2265                 unsigned char *p;
2266
2267                 /* Offset of biCompression. Stored in LE. */
2268                 p = (unsigned char *)track->codec_priv + 16;
2269                 ((MatroskaVideoTrack *)track)->fourcc = (p[3] << 24) |
2270                                  (p[2] << 16) | (p[1] << 8) | p[0];
2271                 codec_id = codec_get_id(codec_bmp_tags, ((MatroskaVideoTrack *)track)->fourcc);
2272
2273             }
2274
2275             /* This is the MS compatibility mode which stores a
2276              * WAVEFORMATEX in the CodecPrivate. */
2277             else if (!strcmp(track->codec_id,
2278                              MATROSKA_CODEC_ID_AUDIO_ACM) &&
2279                 (track->codec_priv_size >= 18) &&
2280                 (track->codec_priv != NULL)) {
2281                 unsigned char *p;
2282                 uint16_t tag;
2283
2284                 /* Offset of wFormatTag. Stored in LE. */
2285                 p = (unsigned char *)track->codec_priv;
2286                 tag = (p[1] << 8) | p[0];
2287                 codec_id = codec_get_id(codec_wav_tags, tag);
2288
2289             }
2290
2291             else if (codec_id == CODEC_ID_AAC && !track->codec_priv_size) {
2292                 MatroskaAudioTrack *audiotrack = (MatroskaAudioTrack *) track;
2293                 int profile = matroska_aac_profile(track->codec_id);
2294                 int sri = matroska_aac_sri(audiotrack->internal_samplerate);
2295                 extradata = av_malloc(5);
2296                 if (extradata == NULL)
2297                     return AVERROR_NOMEM;
2298                 extradata[0] = (profile << 3) | ((sri&0x0E) >> 1);
2299                 extradata[1] = ((sri&0x01) << 7) | (audiotrack->channels<<3);
2300                 if (strstr(track->codec_id, "SBR")) {
2301                     sri = matroska_aac_sri(audiotrack->samplerate);
2302                     extradata[2] = 0x56;
2303                     extradata[3] = 0xE5;
2304                     extradata[4] = 0x80 | (sri<<3);
2305                     extradata_size = 5;
2306                 } else {
2307                     extradata_size = 2;
2308                 }
2309                 track->default_duration = 1024*1000 / audiotrack->internal_samplerate;
2310             }
2311
2312             else if (codec_id == CODEC_ID_TTA) {
2313                 MatroskaAudioTrack *audiotrack = (MatroskaAudioTrack *) track;
2314                 ByteIOContext b;
2315                 extradata_size = 30;
2316                 extradata = av_mallocz(extradata_size);
2317                 if (extradata == NULL)
2318                     return AVERROR_NOMEM;
2319                 init_put_byte(&b, extradata, extradata_size, 1,
2320                               NULL, NULL, NULL, NULL);
2321                 put_buffer(&b, (uint8_t *) "TTA1", 4);
2322                 put_le16(&b, 1);
2323                 put_le16(&b, audiotrack->channels);
2324                 put_le16(&b, audiotrack->bitdepth);
2325                 put_le32(&b, audiotrack->samplerate);
2326                 put_le32(&b, matroska->ctx->duration * audiotrack->samplerate);
2327             }
2328
2329             else if (codec_id == CODEC_ID_RV10 || codec_id == CODEC_ID_RV20 ||
2330                      codec_id == CODEC_ID_RV30 || codec_id == CODEC_ID_RV40) {
2331                 extradata_offset = 26;
2332                 track->codec_priv_size -= extradata_offset;
2333                 track->flags |= MATROSKA_TRACK_REAL_V;
2334             }
2335
2336             if (codec_id == CODEC_ID_NONE) {
2337                 av_log(matroska->ctx, AV_LOG_INFO,
2338                        "Unknown/unsupported CodecID %s.\n",
2339                        track->codec_id);
2340             }
2341
2342             track->stream_index = matroska->num_streams;
2343
2344             matroska->num_streams++;
2345             st = av_new_stream(s, track->stream_index);
2346             if (st == NULL)
2347                 return AVERROR_NOMEM;
2348             av_set_pts_info(st, 64, matroska->time_scale, 1000*1000*1000); /* 64 bit pts in ns */
2349
2350             st->codec->codec_id = codec_id;
2351
2352             if (track->default_duration)
2353                 av_reduce(&st->codec->time_base.num, &st->codec->time_base.den,
2354                           track->default_duration, 1000, 30000);
2355
2356             if(extradata){
2357                 st->codec->extradata = extradata;
2358                 st->codec->extradata_size = extradata_size;
2359             } else if(track->codec_priv && track->codec_priv_size > 0){
2360                 st->codec->extradata = av_malloc(track->codec_priv_size);
2361                 if(st->codec->extradata == NULL)
2362                     return AVERROR_NOMEM;
2363                 st->codec->extradata_size = track->codec_priv_size;
2364                 memcpy(st->codec->extradata,track->codec_priv+extradata_offset,
2365                        track->codec_priv_size);
2366             }
2367
2368             if (track->type == MATROSKA_TRACK_TYPE_VIDEO) {
2369                 MatroskaVideoTrack *videotrack = (MatroskaVideoTrack *)track;
2370
2371                 st->codec->codec_type = CODEC_TYPE_VIDEO;
2372                 st->codec->codec_tag = videotrack->fourcc;
2373                 st->codec->width = videotrack->pixel_width;
2374                 st->codec->height = videotrack->pixel_height;
2375                 if (videotrack->display_width == 0)
2376                     videotrack->display_width= videotrack->pixel_width;
2377                 if (videotrack->display_height == 0)
2378                     videotrack->display_height= videotrack->pixel_height;
2379                 av_reduce(&st->codec->sample_aspect_ratio.num,
2380                           &st->codec->sample_aspect_ratio.den,
2381                           st->codec->height * videotrack->display_width,
2382                           st->codec-> width * videotrack->display_height,
2383                           255);
2384                 st->need_parsing = 2;
2385             } else if (track->type == MATROSKA_TRACK_TYPE_AUDIO) {
2386                 MatroskaAudioTrack *audiotrack = (MatroskaAudioTrack *)track;
2387
2388                 st->codec->codec_type = CODEC_TYPE_AUDIO;
2389                 st->codec->sample_rate = audiotrack->samplerate;
2390                 st->codec->channels = audiotrack->channels;
2391             } else if (track->type == MATROSKA_TRACK_TYPE_SUBTITLE) {
2392                 st->codec->codec_type = CODEC_TYPE_SUBTITLE;
2393             }
2394
2395             /* What do we do with private data? E.g. for Vorbis. */
2396         }
2397         res = 0;
2398     }
2399
2400     return res;
2401 }
2402
2403 static int
2404 matroska_find_track_by_num (MatroskaDemuxContext *matroska,
2405                             int                   num)
2406 {
2407     int i;
2408
2409     for (i = 0; i < matroska->num_tracks; i++)
2410         if (matroska->tracks[i]->num == num)
2411             return i;
2412
2413     return -1;
2414 }
2415
2416 static inline int
2417 rv_offset(uint8_t *data, int slice, int slices)
2418 {
2419     return AV_RL32(data+8*slice+4) + 8*slices;
2420 }
2421
2422 static int
2423 matroska_parse_block(MatroskaDemuxContext *matroska, uint8_t *data, int size,
2424                      int64_t pos, uint64_t cluster_time, uint64_t duration,
2425                      int is_keyframe, int is_bframe)
2426 {
2427     int res = 0;
2428     int track;
2429     AVPacket *pkt;
2430     uint8_t *origdata = data;
2431     int16_t block_time;
2432     uint32_t *lace_size = NULL;
2433     int n, flags, laces = 0;
2434     uint64_t num;
2435
2436     /* first byte(s): tracknum */
2437     if ((n = matroska_ebmlnum_uint(data, size, &num)) < 0) {
2438         av_log(matroska->ctx, AV_LOG_ERROR, "EBML block data error\n");
2439         av_free(origdata);
2440         return res;
2441     }
2442     data += n;
2443     size -= n;
2444
2445     /* fetch track from num */
2446     track = matroska_find_track_by_num(matroska, num);
2447     if (size <= 3 || track < 0 || track >= matroska->num_tracks) {
2448         av_log(matroska->ctx, AV_LOG_INFO,
2449                "Invalid stream %d or size %u\n", track, size);
2450         av_free(origdata);
2451         return res;
2452     }
2453     if(matroska->ctx->streams[ matroska->tracks[track]->stream_index ]->discard >= AVDISCARD_ALL){
2454         av_free(origdata);
2455         return res;
2456     }
2457     if (duration == AV_NOPTS_VALUE)
2458         duration = matroska->tracks[track]->default_duration;
2459
2460     /* block_time (relative to cluster time) */
2461     block_time = (data[0] << 8) | data[1];
2462     data += 2;
2463     size -= 2;
2464     flags = *data;
2465     data += 1;
2466     size -= 1;
2467     if (is_keyframe == -1)
2468         is_keyframe = flags & 1 ? PKT_FLAG_KEY : 0;
2469     switch ((flags & 0x06) >> 1) {
2470         case 0x0: /* no lacing */
2471             laces = 1;
2472             lace_size = av_mallocz(sizeof(int));
2473             lace_size[0] = size;
2474             break;
2475
2476         case 0x1: /* xiph lacing */
2477         case 0x2: /* fixed-size lacing */
2478         case 0x3: /* EBML lacing */
2479             if (size == 0) {
2480                 res = -1;
2481                 break;
2482             }
2483             laces = (*data) + 1;
2484             data += 1;
2485             size -= 1;
2486             lace_size = av_mallocz(laces * sizeof(int));
2487
2488             switch ((flags & 0x06) >> 1) {
2489                 case 0x1: /* xiph lacing */ {
2490                     uint8_t temp;
2491                     uint32_t total = 0;
2492                     for (n = 0; res == 0 && n < laces - 1; n++) {
2493                         while (1) {
2494                             if (size == 0) {
2495                                 res = -1;
2496                                 break;
2497                             }
2498                             temp = *data;
2499                             lace_size[n] += temp;
2500                             data += 1;
2501                             size -= 1;
2502                             if (temp != 0xff)
2503                                 break;
2504                         }
2505                         total += lace_size[n];
2506                     }
2507                     lace_size[n] = size - total;
2508                     break;
2509                 }
2510
2511                 case 0x2: /* fixed-size lacing */
2512                     for (n = 0; n < laces; n++)
2513                         lace_size[n] = size / laces;
2514                     break;
2515
2516                 case 0x3: /* EBML lacing */ {
2517                     uint32_t total;
2518                     n = matroska_ebmlnum_uint(data, size, &num);
2519                     if (n < 0) {
2520                         av_log(matroska->ctx, AV_LOG_INFO,
2521                                "EBML block data error\n");
2522                         break;
2523                     }
2524                     data += n;
2525                     size -= n;
2526                     total = lace_size[0] = num;
2527                     for (n = 1; res == 0 && n < laces - 1; n++) {
2528                         int64_t snum;
2529                         int r;
2530                         r = matroska_ebmlnum_sint (data, size, &snum);
2531                         if (r < 0) {
2532                             av_log(matroska->ctx, AV_LOG_INFO,
2533                                    "EBML block data error\n");
2534                             break;
2535                         }
2536                         data += r;
2537                         size -= r;
2538                         lace_size[n] = lace_size[n - 1] + snum;
2539                         total += lace_size[n];
2540                     }
2541                     lace_size[n] = size - total;
2542                     break;
2543                 }
2544             }
2545             break;
2546     }
2547
2548     if (res == 0) {
2549         int real_v = matroska->tracks[track]->flags & MATROSKA_TRACK_REAL_V;
2550         uint64_t timecode = AV_NOPTS_VALUE;
2551
2552         if (cluster_time != (uint64_t)-1 && cluster_time + block_time >= 0)
2553             timecode = cluster_time + block_time;
2554
2555         for (n = 0; n < laces; n++) {
2556             int slice, slices = 1;
2557
2558             if (real_v) {
2559                 slices = *data++ + 1;
2560                 lace_size[n]--;
2561             }
2562
2563             for (slice=0; slice<slices; slice++) {
2564                 int slice_size, slice_offset = 0;
2565                 if (real_v)
2566                     slice_offset = rv_offset(data, slice, slices);
2567                 if (slice+1 == slices)
2568                     slice_size = lace_size[n] - slice_offset;
2569                 else
2570                     slice_size = rv_offset(data, slice+1, slices) - slice_offset;
2571                 pkt = av_mallocz(sizeof(AVPacket));
2572                 /* XXX: prevent data copy... */
2573                 if (av_new_packet(pkt, slice_size) < 0) {
2574                     res = AVERROR_NOMEM;
2575                     n = laces-1;
2576                     break;
2577                 }
2578                 memcpy (pkt->data, data+slice_offset, slice_size);
2579
2580                 if (n == 0)
2581                     pkt->flags = is_keyframe;
2582                 pkt->stream_index = matroska->tracks[track]->stream_index;
2583
2584                 pkt->pts = timecode;
2585                 pkt->pos = pos;
2586                 pkt->duration = duration;
2587
2588                 if (matroska->tracks[track]->flags & MATROSKA_TRACK_REORDER)
2589                     matroska_queue_packet_reordered(matroska, pkt, is_bframe);
2590                 else
2591                     matroska_queue_packet(matroska, pkt);
2592
2593                 if (timecode != AV_NOPTS_VALUE)
2594                     timecode = duration ? timecode + duration : AV_NOPTS_VALUE;
2595             }
2596             data += lace_size[n];
2597         }
2598     }
2599
2600     av_free(lace_size);
2601     av_free(origdata);
2602     return res;
2603 }
2604
2605 static int
2606 matroska_parse_blockgroup (MatroskaDemuxContext *matroska,
2607                            uint64_t              cluster_time)
2608 {
2609     int res = 0;
2610     uint32_t id;
2611     int is_bframe = 0;
2612     int is_keyframe = PKT_FLAG_KEY, last_num_packets = matroska->num_packets;
2613     uint64_t duration = AV_NOPTS_VALUE;
2614     uint8_t *data;
2615     int size = 0;
2616     int64_t pos = 0;
2617
2618     av_log(matroska->ctx, AV_LOG_DEBUG, "parsing blockgroup...\n");
2619
2620     while (res == 0) {
2621         if (!(id = ebml_peek_id(matroska, &matroska->level_up))) {
2622             res = AVERROR_IO;
2623             break;
2624         } else if (matroska->level_up) {
2625             matroska->level_up--;
2626             break;
2627         }
2628
2629         switch (id) {
2630             /* one block inside the group. Note, block parsing is one
2631              * of the harder things, so this code is a bit complicated.
2632              * See http://www.matroska.org/ for documentation. */
2633             case MATROSKA_ID_BLOCK: {
2634                 pos = url_ftell(&matroska->ctx->pb);
2635                 res = ebml_read_binary(matroska, &id, &data, &size);
2636                 break;
2637             }
2638
2639             case MATROSKA_ID_BLOCKDURATION: {
2640                 if ((res = ebml_read_uint(matroska, &id, &duration)) < 0)
2641                     break;
2642                 duration /= matroska->time_scale;
2643                 break;
2644             }
2645
2646             case MATROSKA_ID_BLOCKREFERENCE: {
2647                 int64_t num;
2648                 /* We've found a reference, so not even the first frame in
2649                  * the lace is a key frame. */
2650                 is_keyframe = 0;
2651                 if (last_num_packets != matroska->num_packets)
2652                     matroska->packets[last_num_packets]->flags = 0;
2653                 if ((res = ebml_read_sint(matroska, &id, &num)) < 0)
2654                     break;
2655                 if (num > 0)
2656                     is_bframe = 1;
2657                 break;
2658             }
2659
2660             default:
2661                 av_log(matroska->ctx, AV_LOG_INFO,
2662                        "Unknown entry 0x%x in blockgroup data\n", id);
2663                 /* fall-through */
2664
2665             case EBML_ID_VOID:
2666                 res = ebml_read_skip(matroska);
2667                 break;
2668         }
2669
2670         if (matroska->level_up) {
2671             matroska->level_up--;
2672             break;
2673         }
2674     }
2675
2676     if (res)
2677         return res;
2678
2679     if (size > 0)
2680         res = matroska_parse_block(matroska, data, size, pos, cluster_time,
2681                                    duration, is_keyframe, is_bframe);
2682
2683     return res;
2684 }
2685
2686 static int
2687 matroska_parse_cluster (MatroskaDemuxContext *matroska)
2688 {
2689     int res = 0;
2690     uint32_t id;
2691     uint64_t cluster_time = 0;
2692     uint8_t *data;
2693     int64_t pos;
2694     int size;
2695
2696     av_log(matroska->ctx, AV_LOG_DEBUG,
2697            "parsing cluster at %"PRId64"\n", url_ftell(&matroska->ctx->pb));
2698
2699     while (res == 0) {
2700         if (!(id = ebml_peek_id(matroska, &matroska->level_up))) {
2701             res = AVERROR_IO;
2702             break;
2703         } else if (matroska->level_up) {
2704             matroska->level_up--;
2705             break;
2706         }
2707
2708         switch (id) {
2709             /* cluster timecode */
2710             case MATROSKA_ID_CLUSTERTIMECODE: {
2711                 uint64_t num;
2712                 if ((res = ebml_read_uint(matroska, &id, &num)) < 0)
2713                     break;
2714                 cluster_time = num;
2715                 break;
2716             }
2717
2718                 /* a group of blocks inside a cluster */
2719             case MATROSKA_ID_BLOCKGROUP:
2720                 if ((res = ebml_read_master(matroska, &id)) < 0)
2721                     break;
2722                 res = matroska_parse_blockgroup(matroska, cluster_time);
2723                 break;
2724
2725             case MATROSKA_ID_SIMPLEBLOCK:
2726                 pos = url_ftell(&matroska->ctx->pb);
2727                 res = ebml_read_binary(matroska, &id, &data, &size);
2728                 if (res == 0)
2729                     res = matroska_parse_block(matroska, data, size, pos,
2730                                                cluster_time, AV_NOPTS_VALUE,
2731                                                -1, 0);
2732                 break;
2733
2734             default:
2735                 av_log(matroska->ctx, AV_LOG_INFO,
2736                        "Unknown entry 0x%x in cluster data\n", id);
2737                 /* fall-through */
2738
2739             case EBML_ID_VOID:
2740                 res = ebml_read_skip(matroska);
2741                 break;
2742         }
2743
2744         if (matroska->level_up) {
2745             matroska->level_up--;
2746             break;
2747         }
2748     }
2749
2750     return res;
2751 }
2752
2753 static int
2754 matroska_read_packet (AVFormatContext *s,
2755                       AVPacket        *pkt)
2756 {
2757     MatroskaDemuxContext *matroska = s->priv_data;
2758     int res = 0;
2759     uint32_t id;
2760
2761     /* Read stream until we have a packet queued. */
2762     while (matroska_deliver_packet(matroska, pkt)) {
2763
2764         /* Have we already reached the end? */
2765         if (matroska->done)
2766             return AVERROR_IO;
2767
2768         while (res == 0) {
2769             if (!(id = ebml_peek_id(matroska, &matroska->level_up))) {
2770                 return AVERROR_IO;
2771             } else if (matroska->level_up) {
2772                 matroska->level_up--;
2773                 break;
2774             }
2775
2776             switch (id) {
2777                 case MATROSKA_ID_CLUSTER:
2778                     if ((res = ebml_read_master(matroska, &id)) < 0)
2779                         break;
2780                     if ((res = matroska_parse_cluster(matroska)) == 0)
2781                         res = 1; /* Parsed one cluster, let's get out. */
2782                     break;
2783
2784                 default:
2785                 case EBML_ID_VOID:
2786                     res = ebml_read_skip(matroska);
2787                     break;
2788             }
2789
2790             if (matroska->level_up) {
2791                 matroska->level_up--;
2792                 break;
2793             }
2794         }
2795
2796         if (res == -1)
2797             matroska->done = 1;
2798     }
2799
2800     return 0;
2801 }
2802
2803 static int
2804 matroska_read_close (AVFormatContext *s)
2805 {
2806     MatroskaDemuxContext *matroska = s->priv_data;
2807     int n = 0;
2808
2809     av_free(matroska->writing_app);
2810     av_free(matroska->muxing_app);
2811     av_free(matroska->index);
2812
2813     if (matroska->packets != NULL) {
2814         for (n = 0; n < matroska->num_packets; n++) {
2815             av_free_packet(matroska->packets[n]);
2816             av_free(matroska->packets[n]);
2817         }
2818         av_free(matroska->packets);
2819     }
2820     if (matroska->packets_reorder) {
2821         for (n = 0; n < matroska->num_packets_reorder; n++) {
2822             av_free_packet(matroska->packets_reorder[n]);
2823             av_free(matroska->packets_reorder[n]);
2824         }
2825         av_free(matroska->packets_reorder);
2826     }
2827
2828     for (n = 0; n < matroska->num_tracks; n++) {
2829         MatroskaTrack *track = matroska->tracks[n];
2830         av_free(track->codec_id);
2831         av_free(track->codec_name);
2832         av_free(track->codec_priv);
2833         av_free(track->name);
2834         av_free(track->language);
2835
2836         av_free(track);
2837     }
2838
2839     return 0;
2840 }
2841
2842 AVInputFormat matroska_demuxer = {
2843     "matroska",
2844     "Matroska file format",
2845     sizeof(MatroskaDemuxContext),
2846     matroska_probe,
2847     matroska_read_header,
2848     matroska_read_packet,
2849     matroska_read_close,
2850 };