static int select_cur_seq_no(HLSContext *c, struct playlist *pls)
{
    int seq_no;

    if (!pls->finished && !c->first_packet &&
        av_gettime() - pls->last_load_time >= default_reload_interval(pls))
        /* reload the playlist since it was suspended */
        parse_playlist(c, pls->url, pls, NULL);

    /* If playback is already in progress (we are just selecting a new
     * playlist) and this is a complete file, find the matching segment
     * by counting durations. */
    if (pls->finished && c->cur_timestamp != AV_NOPTS_VALUE) {
        find_timestamp_in_playlist(c, pls, c->cur_timestamp, &seq_no);
        return seq_no;
    }

    if (!pls->finished) {
        if (!c->first_packet && /* we are doing a segment selection during playback */
            c->cur_seq_no >= pls->start_seq_no &&
            c->cur_seq_no < pls->start_seq_no + pls->n_segments)
            /* While spec 3.4.3 says that we cannot assume anything about the
             * content at the same sequence number on different playlists,
             * in practice this seems to work and doing it otherwise would
             * require us to download a segment to inspect its timestamps. */
            return c->cur_seq_no;

        /* If this is a live stream with more than 3 segments, start at the
         * third last segment. */
        if (pls->n_segments > 3)
            return pls->start_seq_no + pls->n_segments - 3;
    }

    /* Otherwise just start on the first segment. */
    return pls->start_seq_no;
}
Unknown