mov.c

ffmpeg的完整源代码和作者自己写的文档。不但有在Linux的工程哦

/*
 * MOV demuxer
 * Copyright (c) 2001 Fabrice Bellard.
 *
 * This file is part of FFmpeg.
 *
 * FFmpeg 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 2.1 of the License, or (at your option) any later version.
 *
 * FFmpeg 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 FFmpeg; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 */

#include <limits.h>

//#define DEBUG

#include "avformat.h"
#include "riff.h"
#include "isom.h"
#include "dv.h"

#ifdef CONFIG_ZLIB
#include <zlib.h>
#endif

/*
 * First version by Francois Revol [e-mail]
 * Seek function by Gael Chardon [e-mail]
 *
 * Features and limitations:
 * - reads most of the QT files I have (at least the structure),
 *   Sample QuickTime files with mp3 audio can be found at: http://www.3ivx.com/showcase.html
 * - the code is quite ugly... maybe I won't do it recursive next time :-)
 *
 * Funny I didn't know about http://sourceforge.net/projects/qt-ffmpeg/
 * when coding this :) (it's a writer anyway)
 *
 * Reference documents:
 * http://www.geocities.com/xhelmboyx/quicktime/formats/qtm-layout.txt
 * Apple:
 *  http://developer.apple.com/documentation/QuickTime/QTFF/
 *  http://developer.apple.com/documentation/QuickTime/QTFF/qtff.pdf
 * QuickTime is a trademark of Apple (AFAIK :))
 */

#include "qtpalette.h"


#undef NDEBUG
#include <assert.h>

/* the QuickTime file format is quite convoluted...
 * it has lots of index tables, each indexing something in another one...
 * Here we just use what is needed to read the chunks
 */

typedef struct {
    int first;
    int count;
    int id;
} MOV_stsc_t;

typedef struct {
    uint32_t type;
    int64_t offset;
    int64_t size; /* total size (excluding the size and type fields) */
} MOV_atom_t;

typedef struct {
    offset_t offset;
    int64_t size;
} MOV_mdat_t;

struct MOVParseTableEntry;

typedef struct MOVStreamContext {
    int ffindex; /* the ffmpeg stream id */
    int next_chunk;
    unsigned int chunk_count;
    int64_t *chunk_offsets;
    unsigned int stts_count;
    MOV_stts_t *stts_data;
    unsigned int ctts_count;
    MOV_stts_t *ctts_data;
    unsigned int edit_count; /* number of 'edit' (elst atom) */
    unsigned int sample_to_chunk_sz;
    MOV_stsc_t *sample_to_chunk;
    int sample_to_ctime_index;
    int sample_to_ctime_sample;
    unsigned int sample_size;
    unsigned int sample_count;
    int *sample_sizes;
    unsigned int keyframe_count;
    int *keyframes;
    int time_scale;
    int time_rate;
    int current_sample;
    unsigned int bytes_per_frame;
    unsigned int samples_per_frame;
    int dv_audio_container;
} MOVStreamContext;

typedef struct MOVContext {
    AVFormatContext *fc;
    int time_scale;
    int64_t duration; /* duration of the longest track */
    int found_moov; /* when both 'moov' and 'mdat' sections has been found */
    int found_mdat; /* we suppose we have enough data to read the file */
    int64_t mdat_offset;
    int total_streams;
    MOVStreamContext *streams[MAX_STREAMS];

    const struct MOVParseTableEntry *parse_table; /* could be eventually used to change the table */
    /* NOTE: for recursion save to/ restore from local variable! */

    AVPaletteControl palette_control;
    MOV_mdat_t *mdat_list;
    int mdat_count;
    DVDemuxContext *dv_demux;
    AVFormatContext *dv_fctx;
    int isom; /* 1 if file is ISO Media (mp4/3gp) */
} MOVContext;


/* XXX: it's the first time I make a recursive parser I think... sorry if it's ugly :P */

/* those functions parse an atom */
/* return code:
 1: found what I wanted, exit
 0: continue to parse next atom
 -1: error occured, exit
 */
typedef int (*mov_parse_function)(MOVContext *ctx, ByteIOContext *pb, MOV_atom_t atom);

/* links atom IDs to parse functions */
typedef struct MOVParseTableEntry {
    uint32_t type;
    mov_parse_function func;
} MOVParseTableEntry;

static int mov_read_default(MOVContext *c, ByteIOContext *pb, MOV_atom_t atom)
{
    int64_t total_size = 0;
    MOV_atom_t a;
    int i;
    int err = 0;

    a.offset = atom.offset;

    if (atom.size < 0)
        atom.size = INT64_MAX;
    while(((total_size + 8) < atom.size) && !url_feof(pb) && !err) {
        a.size = atom.size;
        a.type=0L;
        if(atom.size >= 8) {
            a.size = get_be32(pb);
            a.type = get_le32(pb);
        }
        total_size += 8;
        a.offset += 8;
        dprintf(c->fc, "type: %08x  %.4s  sz: %"PRIx64"  %"PRIx64"   %"PRIx64"\n", a.type, (char*)&a.type, a.size, atom.size, total_size);
        if (a.size == 1) { /* 64 bit extended size */
            a.size = get_be64(pb) - 8;
            a.offset += 8;
            total_size += 8;
        }
        if (a.size == 0) {
            a.size = atom.size - total_size;
            if (a.size <= 8)
                break;
        }
        a.size -= 8;
        if(a.size < 0 || a.size > atom.size - total_size)
            break;

        for (i = 0; c->parse_table[i].type != 0L
             && c->parse_table[i].type != a.type; i++)
            /* empty */;

        if (c->parse_table[i].type == 0) { /* skip leaf atoms data */
            url_fskip(pb, a.size);
        } else {
            offset_t start_pos = url_ftell(pb);
            int64_t left;
            err = (c->parse_table[i].func)(c, pb, a);
            left = a.size - url_ftell(pb) + start_pos;
            if (left > 0) /* skip garbage at atom end */
                url_fskip(pb, left);
        }

        a.offset += a.size;
        total_size += a.size;
    }

    if (!err && total_size < atom.size && atom.size < 0x7ffff) {
        url_fskip(pb, atom.size - total_size);
    }

    return err;
}

static int mov_read_hdlr(MOVContext *c, ByteIOContext *pb, MOV_atom_t atom)
{
    AVStream *st = c->fc->streams[c->fc->nb_streams-1];
    uint32_t type;
    uint32_t ctype;

    get_byte(pb); /* version */
    get_byte(pb); get_byte(pb); get_byte(pb); /* flags */

    /* component type */
    ctype = get_le32(pb);
    type = get_le32(pb); /* component subtype */

    dprintf(c->fc, "ctype= %c%c%c%c (0x%08x)\n", *((char *)&ctype), ((char *)&ctype)[1], ((char *)&ctype)[2], ((char *)&ctype)[3], (int) ctype);
    dprintf(c->fc, "stype= %c%c%c%c\n", *((char *)&type), ((char *)&type)[1], ((char *)&type)[2], ((char *)&type)[3]);
    if(!ctype)
        c->isom = 1;
    if(type == MKTAG('v', 'i', 'd', 'e'))
        st->codec->codec_type = CODEC_TYPE_VIDEO;
    else if(type == MKTAG('s', 'o', 'u', 'n'))
        st->codec->codec_type = CODEC_TYPE_AUDIO;
    else if(type == MKTAG('m', '1', 'a', ' '))
        st->codec->codec_id = CODEC_ID_MP2;
    else if(type == MKTAG('s', 'u', 'b', 'p')) {
        st->codec->codec_type = CODEC_TYPE_SUBTITLE;
        st->codec->codec_id = CODEC_ID_DVD_SUBTITLE;
    }
    get_be32(pb); /* component  manufacture */
    get_be32(pb); /* component flags */
    get_be32(pb); /* component flags mask */

    if(atom.size <= 24)
        return 0; /* nothing left to read */

    url_fskip(pb, atom.size - (url_ftell(pb) - atom.offset));
    return 0;
}

static int mp4_read_descr_len(ByteIOContext *pb)
{
    int len = 0;
    int count = 4;
    while (count--) {
        int c = get_byte(pb);
        len = (len << 7) | (c & 0x7f);
        if (!(c & 0x80))
            break;
    }
    return len;
}

static int mp4_read_descr(MOVContext *c, ByteIOContext *pb, int *tag)
{
    int len;
    *tag = get_byte(pb);
    len = mp4_read_descr_len(pb);
    dprintf(c->fc, "MPEG4 description: tag=0x%02x len=%d\n", *tag, len);
    return len;
}

#define MP4ESDescrTag                   0x03
#define MP4DecConfigDescrTag            0x04
#define MP4DecSpecificDescrTag          0x05

static int mov_read_esds(MOVContext *c, ByteIOContext *pb, MOV_atom_t atom)
{
    AVStream *st = c->fc->streams[c->fc->nb_streams-1];
    int tag, len;

    get_be32(pb); /* version + flags */
    len = mp4_read_descr(c, pb, &tag);
    if (tag == MP4ESDescrTag) {
        get_be16(pb); /* ID */
        get_byte(pb); /* priority */
    } else
        get_be16(pb); /* ID */

    len = mp4_read_descr(c, pb, &tag);
    if (tag == MP4DecConfigDescrTag) {
        int object_type_id = get_byte(pb);
        get_byte(pb); /* stream type */
        get_be24(pb); /* buffer size db */
        get_be32(pb); /* max bitrate */
        get_be32(pb); /* avg bitrate */

        st->codec->codec_id= codec_get_id(ff_mp4_obj_type, object_type_id);
        dprintf(c->fc, "esds object type id %d\n", object_type_id);
        len = mp4_read_descr(c, pb, &tag);
        if (tag == MP4DecSpecificDescrTag) {
            dprintf(c->fc, "Specific MPEG4 header len=%d\n", len);
            st->codec->extradata = av_mallocz(len + FF_INPUT_BUFFER_PADDING_SIZE);
            if (st->codec->extradata) {
                get_buffer(pb, st->codec->extradata, len);
                st->codec->extradata_size = len;
                /* from mplayer */
                if ((*st->codec->extradata >> 3) == 29) {
                    st->codec->codec_id = CODEC_ID_MP3ON4;
                }
            }
        }
    }
    return 0;
}

/* this atom contains actual media data */
static int mov_read_mdat(MOVContext *c, ByteIOContext *pb, MOV_atom_t atom)
{
    if(atom.size == 0) /* wrong one (MP4) */
        return 0;
    c->mdat_list = av_realloc(c->mdat_list, (c->mdat_count + 1) * sizeof(*c->mdat_list));
    c->mdat_list[c->mdat_count].offset = atom.offset;
    c->mdat_list[c->mdat_count].size = atom.size;
    c->mdat_count++;
    c->found_mdat=1;
    c->mdat_offset = atom.offset;
    if(c->found_moov)
        return 1; /* found both, just go */
    url_fskip(pb, atom.size);
    return 0; /* now go for moov */
}

static int mov_read_ftyp(MOVContext *c, ByteIOContext *pb, MOV_atom_t atom)
{
    uint32_t type = get_le32(pb);

    if (type != MKTAG('q','t',' ',' '))
        c->isom = 1;
    av_log(c->fc, AV_LOG_DEBUG, "ISO: File Type Major Brand: %.4s\n",(char *)&type);
    get_be32(pb); /* minor version */
    url_fskip(pb, atom.size - 8);
    return 0;
}

/* this atom should contain all header atoms */
static int mov_read_moov(MOVContext *c, ByteIOContext *pb, MOV_atom_t atom)
{
    int err;

    err = mov_read_default(c, pb, atom);
    /* we parsed the 'moov' atom, we can terminate the parsing as soon as we find the 'mdat' */
    /* so we don't parse the whole file if over a network */
    c->found_moov=1;
    if(c->found_mdat)
        return 1; /* found both, just go */
    return 0; /* now go for mdat */
}


static int mov_read_mdhd(MOVContext *c, ByteIOContext *pb, MOV_atom_t atom)
{
    AVStream *st = c->fc->streams[c->fc->nb_streams-1];
    MOVStreamContext *sc = st->priv_data;
    int version = get_byte(pb);
    int lang;

    if (version > 1)
        return 1; /* unsupported */

    get_byte(pb); get_byte(pb);
    get_byte(pb); /* flags */

    if (version == 1) {
        get_be64(pb);
        get_be64(pb);
    } else {
        get_be32(pb); /* creation time */
        get_be32(pb); /* modification time */
    }

    sc->time_scale = get_be32(pb);
    st->duration = (version == 1) ? get_be64(pb) : get_be32(pb); /* duration */

    lang = get_be16(pb); /* language */
    ff_mov_lang_to_iso639(lang, st->language);
    get_be16(pb); /* quality */

    return 0;
}

static int mov_read_mvhd(MOVContext *c, ByteIOContext *pb, MOV_atom_t atom)
{
    int version = get_byte(pb); /* version */
    get_byte(pb); get_byte(pb); get_byte(pb); /* flags */

    if (version == 1) {
        get_be64(pb);
        get_be64(pb);
    } else {
        get_be32(pb); /* creation time */
        get_be32(pb); /* modification time */
    }
    c->time_scale = get_be32(pb); /* time scale */

    dprintf(c->fc, "time scale = %i\n", c->time_scale);

    c->duration = (version == 1) ? get_be64(pb) : get_be32(pb); /* duration */
    get_be32(pb); /* preferred scale */

    get_be16(pb); /* preferred volume */

    url_fskip(pb, 10); /* reserved */