Rav Reichman of YU said (jokingly) that any music you’re allowed to listen to the rest of the year is muttar during sfira and that that would be enough of a restriction for most people.
thats a great question. and rav reichman’s answer (doesn’t need my haskama but) is a great answer. I heard that someone asked rav aharon soloveitchik zt”l if you’re allowed to watch a movie during sefira. he said, “there’s no additional issur.”