matroska.c

ffmpeg源码分析

/*
 * Matroska file demuxer (no muxer yet)
 * Copyright (c) 2003-2004 The ffmpeg Project
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 */

/**
 * @file matroska.c
 * Matroska file demuxer
 * by Ronald Bultje <[e-mail]>
 * with a little help from Moritz Bunkus <[e-mail]>
 * Specs available on the matroska project page:
 * http://www.matroska.org/.
 */

#include "avformat.h"
/* For codec_get_bmp_id and codec_get_wav_id. */
#include "avi.h"
#include "intfloat_readwrite.h"

/* EBML version supported */
#define EBML_VERSION 1

/* top-level master-IDs */
#define EBML_ID_HEADER             0x1A45DFA3

/* IDs in the HEADER master */
#define EBML_ID_EBMLVERSION        0x4286
#define EBML_ID_EBMLREADVERSION    0x42F7
#define EBML_ID_EBMLMAXIDLENGTH    0x42F2
#define EBML_ID_EBMLMAXSIZELENGTH  0x42F3
#define EBML_ID_DOCTYPE            0x4282
#define EBML_ID_DOCTYPEVERSION     0x4287
#define EBML_ID_DOCTYPEREADVERSION 0x4285

/* general EBML types */
#define EBML_ID_VOID               0xEC

/*
 * Matroska element IDs. max. 32-bit.
 */

/* toplevel segment */
#define MATROSKA_ID_SEGMENT    0x18538067

/* matroska top-level master IDs */
#define MATROSKA_ID_INFO       0x1549A966
#define MATROSKA_ID_TRACKS     0x1654AE6B
#define MATROSKA_ID_CUES       0x1C53BB6B
#define MATROSKA_ID_TAGS       0x1254C367
#define MATROSKA_ID_SEEKHEAD   0x114D9B74
#define MATROSKA_ID_CLUSTER    0x1F43B675

/* IDs in the info master */
#define MATROSKA_ID_TIMECODESCALE 0x2AD7B1
#define MATROSKA_ID_DURATION   0x4489
#define MATROSKA_ID_WRITINGAPP 0x5741
#define MATROSKA_ID_MUXINGAPP  0x4D80
#define MATROSKA_ID_DATEUTC    0x4461

/* ID in the tracks master */
#define MATROSKA_ID_TRACKENTRY 0xAE

/* IDs in the trackentry master */
#define MATROSKA_ID_TRACKNUMBER 0xD7
#define MATROSKA_ID_TRACKUID   0x73C5
#define MATROSKA_ID_TRACKTYPE  0x83
#define MATROSKA_ID_TRACKAUDIO 0xE1
#define MATROSKA_ID_TRACKVIDEO 0xE0
#define MATROSKA_ID_CODECID    0x86
#define MATROSKA_ID_CODECPRIVATE 0x63A2
#define MATROSKA_ID_CODECNAME  0x258688
#define MATROSKA_ID_CODECINFOURL 0x3B4040
#define MATROSKA_ID_CODECDOWNLOADURL 0x26B240
#define MATROSKA_ID_TRACKNAME  0x536E
#define MATROSKA_ID_TRACKLANGUAGE 0x22B59C
#define MATROSKA_ID_TRACKFLAGENABLED 0xB9
#define MATROSKA_ID_TRACKFLAGDEFAULT 0x88
#define MATROSKA_ID_TRACKFLAGLACING 0x9C
#define MATROSKA_ID_TRACKMINCACHE 0x6DE7
#define MATROSKA_ID_TRACKMAXCACHE 0x6DF8
#define MATROSKA_ID_TRACKDEFAULTDURATION 0x23E383

/* IDs in the trackvideo master */
#define MATROSKA_ID_VIDEOFRAMERATE 0x2383E3
#define MATROSKA_ID_VIDEODISPLAYWIDTH 0x54B0
#define MATROSKA_ID_VIDEODISPLAYHEIGHT 0x54BA
#define MATROSKA_ID_VIDEOPIXELWIDTH 0xB0
#define MATROSKA_ID_VIDEOPIXELHEIGHT 0xBA
#define MATROSKA_ID_VIDEOFLAGINTERLACED 0x9A
#define MATROSKA_ID_VIDEOSTEREOMODE 0x53B9
#define MATROSKA_ID_VIDEOASPECTRATIO 0x54B3
#define MATROSKA_ID_VIDEOCOLOURSPACE 0x2EB524

/* IDs in the trackaudio master */
#define MATROSKA_ID_AUDIOSAMPLINGFREQ 0xB5
#define MATROSKA_ID_AUDIOBITDEPTH 0x6264
#define MATROSKA_ID_AUDIOCHANNELS 0x9F

/* ID in the cues master */
#define MATROSKA_ID_POINTENTRY 0xBB

/* IDs in the pointentry master */
#define MATROSKA_ID_CUETIME    0xB3
#define MATROSKA_ID_CUETRACKPOSITION 0xB7

/* IDs in the cuetrackposition master */
#define MATROSKA_ID_CUETRACK   0xF7
#define MATROSKA_ID_CUECLUSTERPOSITION 0xF1

/* IDs in the tags master */
/* TODO */

/* IDs in the seekhead master */
#define MATROSKA_ID_SEEKENTRY  0x4DBB

/* IDs in the seekpoint master */
#define MATROSKA_ID_SEEKID     0x53AB
#define MATROSKA_ID_SEEKPOSITION 0x53AC

/* IDs in the cluster master */
#define MATROSKA_ID_CLUSTERTIMECODE 0xE7
#define MATROSKA_ID_BLOCKGROUP 0xA0

/* IDs in the blockgroup master */
#define MATROSKA_ID_BLOCK      0xA1
#define MATROSKA_ID_BLOCKDURATION 0x9B
#define MATROSKA_ID_BLOCKREFERENCE 0xFB

typedef enum {
  MATROSKA_TRACK_TYPE_VIDEO    = 0x1,
  MATROSKA_TRACK_TYPE_AUDIO    = 0x2,
  MATROSKA_TRACK_TYPE_COMPLEX  = 0x3,
  MATROSKA_TRACK_TYPE_LOGO     = 0x10,
  MATROSKA_TRACK_TYPE_SUBTITLE = 0x11,
  MATROSKA_TRACK_TYPE_CONTROL  = 0x20,
} MatroskaTrackType;

typedef enum {
  MATROSKA_EYE_MODE_MONO  = 0x0,
  MATROSKA_EYE_MODE_RIGHT = 0x1,
  MATROSKA_EYE_MODE_LEFT  = 0x2,
  MATROSKA_EYE_MODE_BOTH  = 0x3,
} MatroskaEyeMode;

typedef enum {
  MATROSKA_ASPECT_RATIO_MODE_FREE  = 0x0,
  MATROSKA_ASPECT_RATIO_MODE_KEEP  = 0x1,
  MATROSKA_ASPECT_RATIO_MODE_FIXED = 0x2,
} MatroskaAspectRatioMode;

/*
 * These aren't in any way "matroska-form" things,
 * it's just something I use in the muxer/demuxer.
 */

typedef enum {
  MATROSKA_TRACK_ENABLED = (1<<0),
  MATROSKA_TRACK_DEFAULT = (1<<1),
  MATROSKA_TRACK_LACING  = (1<<2),
  MATROSKA_TRACK_SHIFT   = (1<<16)
} MatroskaTrackFlags;

typedef enum {
  MATROSKA_VIDEOTRACK_INTERLACED = (MATROSKA_TRACK_SHIFT<<0)
} MatroskaVideoTrackFlags;

/*
 * Matroska Codec IDs. Strings.
 */

typedef struct CodecTags{
    char *str;
    enum CodecID id;
}CodecTags;

#define MATROSKA_CODEC_ID_VIDEO_VFW_FOURCC   "V_MS/VFW/FOURCC"
#define MATROSKA_CODEC_ID_AUDIO_ACM          "A_MS/ACM"

CodecTags codec_tags[]={
//    {"V_MS/VFW/FOURCC"  , CODEC_ID_NONE},
    {"V_UNCOMPRESSED"   , CODEC_ID_RAWVIDEO},
    {"V_MPEG4/ISO/SP"   , CODEC_ID_MPEG4},
    {"V_MPEG4/ISO/ASP"  , CODEC_ID_MPEG4},
    {"V_MPEG4/ISO/AP"   , CODEC_ID_MPEG4},
    {"V_MPEG4/ISO/AVC"  , CODEC_ID_H264},
    {"V_MPEG4/MS/V3"    , CODEC_ID_MSMPEG4V3},
    {"V_MPEG1"          , CODEC_ID_MPEG1VIDEO},
    {"V_MPEG2"          , CODEC_ID_MPEG2VIDEO},
    {"V_MJPEG"          , CODEC_ID_MJPEG},
    {"V_REAL/RV10"      , CODEC_ID_RV10},
    {"V_REAL/RV20"      , CODEC_ID_RV20},
    {"V_REAL/RV30"      , CODEC_ID_RV30},
    {"V_REAL/RV40"      , CODEC_ID_RV40},
/* TODO: Real/Quicktime */

//    {"A_MS/ACM"         , CODEC_ID_NONE},
    {"A_MPEG/L1"        , CODEC_ID_MP3},
    {"A_MPEG/L2"        , CODEC_ID_MP3},
    {"A_MPEG/L3"        , CODEC_ID_MP3},
    {"A_PCM/INT/BIG"    , CODEC_ID_PCM_U16BE},
    {"A_PCM/INT/LIT"    , CODEC_ID_PCM_U16LE},
//    {"A_PCM/FLOAT/IEEE" , CODEC_ID_NONE},
    {"A_AC3"            , CODEC_ID_AC3},
    {"A_DTS"            , CODEC_ID_DTS},
    {"A_VORBIS"         , CODEC_ID_VORBIS},
    {"A_AAC/MPEG2/"     , CODEC_ID_AAC},
    {"A_AAC/MPEG4/"     , CODEC_ID_AAC},
    {NULL               , CODEC_ID_NONE}
/* TODO: AC3-9/10 (?), Real, Musepack, Quicktime */
};

/* max. depth in the EBML tree structure */
#define EBML_MAX_DEPTH 16

typedef struct Track {
    MatroskaTrackType type;

    /* Unique track number and track ID. stream_index is the index that
     * the calling app uses for this track. */
    uint32_t num,
        uid,
        stream_index;

    char *name,
        *language;

    char *codec_id,
        *codec_name;

    unsigned char *codec_priv;
    int codec_priv_size;

    int64_t default_duration;
    MatroskaTrackFlags flags;
} MatroskaTrack;

typedef struct MatroskaVideoTrack {
    MatroskaTrack track;

    int pixel_width,
        pixel_height,
        display_width,
        display_height;

    uint32_t fourcc;

    MatroskaAspectRatioMode ar_mode;
    MatroskaEyeMode eye_mode;

    //..
} MatroskaVideoTrack;

typedef struct MatroskaAudioTrack {
    MatroskaTrack track;

    int channels,
        bitdepth,
        samplerate;
    //..
} MatroskaAudioTrack;

typedef struct MatroskaSubtitleTrack {
    MatroskaTrack track;

    //..
} MatroskaSubtitleTrack;

typedef struct MatroskaLevel {
    uint64_t start, length;
} MatroskaLevel;

typedef struct MatroskaDemuxIndex {
  uint64_t        pos;   /* of the corresponding *cluster*! */
  uint16_t        track; /* reference to 'num' */
  uint64_t        time;  /* in nanoseconds */
} MatroskaDemuxIndex;

typedef struct MatroskaDemuxContext {
    AVFormatContext *ctx;

    /* ebml stuff */
    int num_levels;
    MatroskaLevel levels[EBML_MAX_DEPTH];
    int level_up;

    /* matroska stuff */
    char *writing_app,
        *muxing_app;
    int64_t created;

    /* timescale in the file */
    int64_t time_scale;

    /* position (time, ns) */
    int64_t pos;

    /* num_streams is the number of streams that av_new_stream() was called
     * for ( = that are available to the calling program). */
    int num_tracks, num_streams;
    MatroskaTrack *tracks[MAX_STREAMS];

    /* cache for ID peeking */
    uint32_t peek_id;

    /* byte position of the segment inside the stream */
    offset_t segment_start;

    /* The packet queue. */
    AVPacket **packets;
    int num_packets;

    /* have we already parse metadata/cues/clusters? */
    int metadata_parsed,
        index_parsed,
        done;

    /* The index for seeking. */
    int num_indexes;
    MatroskaDemuxIndex *index;
} MatroskaDemuxContext;

/*
 * The first few functions handle EBML file parsing. The rest
 * is the document interpretation. Matroska really just is a
 * EBML file.
 */

/*
 * Return: the amount of levels in the hierarchy that the
 * current element lies higher than the previous one.
 * The opposite isn't done - that's auto-done using master
 * element reading.
 */

static int
ebml_read_element_level_up (MatroskaDemuxContext *matroska)
{
    ByteIOContext *pb = &matroska->ctx->pb;
    offset_t pos = url_ftell(pb);
    int num = 0;

    while (matroska->num_levels > 0) {
        MatroskaLevel *level = &matroska->levels[matroska->num_levels - 1];

        if (pos >= level->start + level->length) {
            matroska->num_levels--;
            num++;
        } else {
            break;
        }
    }

    return num;
}

/*
 * Read: an "EBML number", which is defined as a variable-length
 * array of bytes. The first byte indicates the length by giving a
 * number of 0-bits followed by a one. The position of the first
 * "one" bit inside the first byte indicates the length of this
 * number.
 * Returns: num. of bytes read. < 0 on error.
 */

static int
ebml_read_num (MatroskaDemuxContext *matroska,
               int                   max_size,
               uint64_t             *number)
{
    ByteIOContext *pb = &matroska->ctx->pb;
    int len_mask = 0x80, read = 1, n = 1;
    int64_t total = 0;

    /* the first byte tells us the length in bytes - get_byte() can normally
     * return 0, but since that's not a valid first ebmlID byte, we can
     * use it safely here to catch EOS. */
    if (!(total = get_byte(pb))) {
        /* we might encounter EOS here */
        if (!url_feof(pb)) {
            offset_t pos = url_ftell(pb);
            av_log(matroska->ctx, AV_LOG_ERROR,
                   "Read error at pos. %"PRIu64" (0x%"PRIx64")\n",
                   pos, pos);
        }
        return AVERROR_IO; /* EOS or actual I/O error */
    }

    /* get the length of the EBML number */
    while (read <= max_size && !(total & len_mask)) {
        read++;
        len_mask >>= 1;
    }
    if (read > max_size) {
        offset_t pos = url_ftell(pb) - 1;
        av_log(matroska->ctx, AV_LOG_ERROR,
               "Invalid EBML number size tag 0x%02x at pos %"PRIu64" (0x%"PRIx64")\n",
               (uint8_t) total, pos, pos);
        return AVERROR_INVALIDDATA;