int tag, len;
AVStream *st = 0; int tag, len, i, frame;
static int swf_read_packet(AVFormatContext *s, AVPacket *pkt){    ByteIOContext *pb = &s->pb;    int tag, len;        for(;;) {        tag = get_swf_tag(pb, &len);        if (tag < 0)             return -EIO;        if (tag == TAG_STREAMBLOCK) {            av_new_packet(pkt, len);            get_buffer(pb, pkt->data, pkt->size);            break;        } else {            url_fskip(pb, len);        }    }    return 0;}