static int64_t asf_read_pts(AVFormatContext *s, int64_t pos)
static int64_t asf_read_pts(AVFormatContext *s, int64_t *ppos, int stream_index)
static int64_t asf_read_pts(AVFormatContext *s, int64_t pos){    ASFContext *asf = s->priv_data;    AVPacket pkt1, *pkt = &pkt1;    int64_t seek_pos;    // ensure we are on the byte boundry    if (pos > asf->packet_size)        seek_pos = s->data_offset + ((pos / asf->packet_size) * asf->packet_size);    else seek_pos = pos;    url_fseek(&s->pb, seek_pos, SEEK_SET);    asf_reset_header(s);    if (av_read_frame(s, pkt) < 0)    	return AV_NOPTS_VALUE;    return pkt->pts;}