mov.c

F:图像处理资料264264书籍ffmpeg-0.4.9-pre1VideoStream.rar 一个视频解压缩源代码

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

    if (!err && total_size < atom.size && atom.size < 0x7ffff) {
	//av_log(NULL, AV_LOG_DEBUG, "RESET  %Ld  %Ld  err:%d\n", atom.size, total_size, err);
        url_fskip(pb, atom.size - total_size);
    }

#ifdef DEBUG
    debug_indent--;
#endif
    return err;
}

static int mov_read_ctab(MOVContext *c, ByteIOContext *pb, MOV_atom_t atom)
{
    unsigned int len;
    MOV_ctab_t *t;
    //url_fskip(pb, atom.size); // for now
    c->ctab = av_realloc(c->ctab, ++c->ctab_size);
    t = c->ctab[c->ctab_size];
    t->seed = get_be32(pb);
    t->flags = get_be16(pb);
    t->size = get_be16(pb) + 1;
    len = 2 * t->size * 4;
    if (len > 0) {
	t->clrs = av_malloc(len); // 16bit A R G B
	if (t->clrs)
	    get_buffer(pb, t->clrs, len);
    }

    return 0;
}

static int mov_read_hdlr(MOVContext *c, ByteIOContext *pb, MOV_atom_t atom)
{
    AVStream *st = c->fc->streams[c->fc->nb_streams-1];
    int len = 0;
    uint32_t type;
    uint32_t ctype;

    print_atom("hdlr", atom);

    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 */

#ifdef DEBUG
    av_log(NULL, AV_LOG_DEBUG, "ctype= %c%c%c%c (0x%08lx)\n", *((char *)&ctype), ((char *)&ctype)[1], ((char *)&ctype)[2], ((char *)&ctype)[3], (long) ctype);
    av_log(NULL, AV_LOG_DEBUG, "stype= %c%c%c%c\n", *((char *)&type), ((char *)&type)[1], ((char *)&type)[2], ((char *)&type)[3]);
#endif
#ifdef DEBUG
/* XXX: yeah this is ugly... */
    if(ctype == MKTAG('m', 'h', 'l', 'r')) { /* MOV */
        if(type == MKTAG('v', 'i', 'd', 'e'))
            puts("hdlr: vide");
        else if(type == MKTAG('s', 'o', 'u', 'n'))
            puts("hdlr: soun");
    } else if(ctype == 0) { /* MP4 */
        if(type == MKTAG('v', 'i', 'd', 'e'))
            puts("hdlr: vide");
        else if(type == MKTAG('s', 'o', 'u', 'n'))
            puts("hdlr: soun");
        else if(type == MKTAG('o', 'd', 's', 'm'))
            puts("hdlr: odsm");
        else if(type == MKTAG('s', 'd', 's', 'm'))
            puts("hdlr: sdsm");
    } else puts("hdlr: meta");
#endif

    if(ctype == MKTAG('m', 'h', 'l', 'r')) { /* MOV */
        /* helps parsing the string hereafter... */
        c->mp4 = 0;
        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(ctype == 0) { /* MP4 */
        /* helps parsing the string hereafter... */
        c->mp4 = 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;
    }
    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 */
    /* XXX: MP4 uses a C string, not a pascal one */
    /* component name */

    if(c->mp4) {
        /* .mp4: C string */
        while(get_byte(pb) && (++len < (atom.size - 24)));
    } else {
        /* .mov: PASCAL string */
#ifdef DEBUG
        char* buf;
#endif
        len = get_byte(pb);
#ifdef DEBUG
	buf = (uint8_t*) av_malloc(len+1);
	if (buf) {
	    get_buffer(pb, buf, len);
	    buf[len] = '\0';
	    av_log(NULL, AV_LOG_DEBUG, "**buf='%s'\n", buf);
	    av_free(buf);
	} else
#endif
	    url_fskip(pb, len);
    }

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

static int mov_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 mov_mp4_read_descr(ByteIOContext *pb, int *tag)
{
    int len;
    *tag = get_byte(pb);
    len = mov_mp4_read_descr_len(pb);
#ifdef DEBUG
    av_log(NULL, AV_LOG_DEBUG, "MPEG4 description: tag=0x%02x len=%d\n", *tag, len);
#endif
    return len;
}

static inline unsigned int get_be24(ByteIOContext *s)
{
    unsigned int val;
    val = get_byte(s) << 16;
    val |= get_byte(s) << 8;
    val |= get_byte(s);
    return val;
}

static int mov_read_esds(MOVContext *c, ByteIOContext *pb, MOV_atom_t atom)
{
    AVStream *st = c->fc->streams[c->fc->nb_streams-1];
    MOVStreamContext *sc = (MOVStreamContext *)st->priv_data;
    int64_t start_pos = url_ftell(pb);
    int tag, len;

    print_atom("esds", atom);

    /* Well, broken but suffisant for some MP4 streams */
    get_be32(pb); /* version + flags */
    len = mov_mp4_read_descr(pb, &tag);
    if (tag == MP4ESDescrTag) {
	get_be16(pb); /* ID */
	get_byte(pb); /* priority */
    } else
	get_be16(pb); /* ID */

    len = mov_mp4_read_descr(pb, &tag);
    if (tag == MP4DecConfigDescrTag) {
	sc->esds.object_type_id = get_byte(pb);
	sc->esds.stream_type = get_byte(pb);
	sc->esds.buffer_size_db = get_be24(pb);
	sc->esds.max_bitrate = get_be32(pb);
	sc->esds.avg_bitrate = get_be32(pb);

	len = mov_mp4_read_descr(pb, &tag);
	//av_log(NULL, AV_LOG_DEBUG, "LEN %d  TAG %d  m:%d a:%d\n", len, tag, sc->esds.max_bitrate, sc->esds.avg_bitrate);
	if (tag == MP4DecSpecificDescrTag) {
#ifdef DEBUG
	    av_log(NULL, AV_LOG_DEBUG, "Specific MPEG4 header len=%d\n", len);
#endif
	    st->codec.extradata = (uint8_t*) av_mallocz(len);
	    if (st->codec.extradata) {
		get_buffer(pb, st->codec.extradata, len);
		st->codec.extradata_size = len;
	    }
	}
    }
    /* in any case, skip garbage */
    url_fskip(pb, atom.size - ((url_ftell(pb) - start_pos)));
    return 0;
}

/* this atom contains actual media data */
static int mov_read_mdat(MOVContext *c, ByteIOContext *pb, MOV_atom_t atom)
{
    print_atom("mdat", atom);

    if(atom.size == 0) /* wrong one (MP4) */
        return 0;
    c->found_mdat=1;
    c->mdat_offset = atom.offset;
    c->mdat_size = atom.size;
    if(c->found_moov)
        return 1; /* found both, just go */
    url_fskip(pb, atom.size);
    return 0; /* now go for moov */
}

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

    print_atom("moov", atom);

    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)
{
    print_atom("mdhd", atom);

    get_byte(pb); /* version */

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

    get_be32(pb); /* creation time */
    get_be32(pb); /* modification time */

    c->streams[c->fc->nb_streams-1]->time_scale = get_be32(pb);

#ifdef DEBUG
    av_log(NULL, AV_LOG_DEBUG, "track[%i].time_scale = %i\n", c->fc->nb_streams-1, c->streams[c->fc->nb_streams-1]->time_scale); /* time scale */
#endif
    get_be32(pb); /* duration */

    get_be16(pb); /* language */
    get_be16(pb); /* quality */

    return 0;
}

static int mov_read_mvhd(MOVContext *c, ByteIOContext *pb, MOV_atom_t atom)
{
    print_atom("mvhd", atom);

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

    get_be32(pb); /* creation time */
    get_be32(pb); /* modification time */
    c->time_scale = get_be32(pb); /* time scale */
#ifdef DEBUG
    av_log(NULL, AV_LOG_DEBUG, "time scale = %i\n", c->time_scale);
#endif
    c->duration = get_be32(pb); /* duration */
    get_be32(pb); /* preferred scale */

    get_be16(pb); /* preferred volume */

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

    url_fskip(pb, 36); /* display matrix */

    get_be32(pb); /* preview time */
    get_be32(pb); /* preview duration */
    get_be32(pb); /* poster time */
    get_be32(pb); /* selection time */
    get_be32(pb); /* selection duration */
    get_be32(pb); /* current time */
    get_be32(pb); /* next track ID */

    return 0;
}

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

    // currently SVQ3 decoder expect full STSD header - so let's fake it
    // this should be fixed and just SMI header should be passed
    av_free(st->codec.extradata);
    st->codec.extradata_size = 0x5a + atom.size;
    st->codec.extradata = (uint8_t*) av_mallocz(st->codec.extradata_size);

    if (st->codec.extradata) {
	strcpy(st->codec.extradata, "SVQ3"); // fake
	get_buffer(pb, st->codec.extradata + 0x5a, atom.size);
	//av_log(NULL, AV_LOG_DEBUG, "Reading SMI %Ld  %s\n", atom.size, (char*)st->codec.extradata + 0x5a);
    } else
	url_fskip(pb, atom.size);

    return 0;
}

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

    print_atom("stco", atom);

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

    entries = get_be32(pb);
    sc->chunk_count = entries;
    sc->chunk_offsets = (int64_t*) av_malloc(entries * sizeof(int64_t));
    if (!sc->chunk_offsets)
        return -1;
    if (atom.type == MKTAG('s', 't', 'c', 'o')) {
        for(i=0; i<entries; i++) {
            sc->chunk_offsets[i] = get_be32(pb);
        }
    } else if (atom.type == MKTAG('c', 'o', '6', '4')) {
        for(i=0; i<entries; i++) {
            sc->chunk_offsets[i] = get_be64(pb);
        }
    } else
        return -1;
#ifdef DEBUG
/*
    for(i=0; i<entries; i++) {
        av_log(NULL, AV_LOG_DEBUG, "chunk offset=0x%Lx\n", sc->chunk_offsets[i]);
    }
*/
#endif
    return 0;
}

static int mov_read_stsd(MOVContext *c, ByteIOContext *pb, MOV_atom_t atom)
{
    AVStream *st = c->fc->streams[c->fc->nb_streams-1];
    //MOVStreamContext *sc = (MOVStreamContext *)st->priv_data;
    int entries, frames_per_sample;
    uint32_t format;

    /* for palette traversal */
    int color_depth;
    int color_start;
    int color_count;
    int color_end;
    int color_index;
    int color_dec;
    int color_greyscale;
    unsigned char *color_table;
    int j;
    unsigned char r, g, b;

    print_atom("stsd", atom);

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

    entries = get_be32(pb);

    while(entries--) { //Parsing Sample description table
        enum CodecID id;
	int size = get_be32(pb); /* size */
        format = get_le32(pb); /* data format */

        get_be32(pb); /* reserved */
        get_be16(pb); /* reserved */