avio_seek(s->pb, st->index_entries[st->nb_index_entries-1].pos, SEEK_SET);
matroska->current_id = 0;
while ((index = av_index_search_timestamp(st, timestamp, flags)) < 0) {
avio_seek(s->pb, st->index_entries[st->nb_index_entries-1].pos, SEEK_SET);
matroska->current_id = 0;
while ((index = av_index_search_timestamp(st, timestamp, flags)) < 0) {