<?php

$resposta = 'Stream #0:0(und): Video: mpeg4 ...
    Stream #0:1(jpn): Audio: mp3 ...
    Stream #0:1(por): Subtitle:';

if (preg_match_all('/Stream\s[#](\d+:\d+)(\(\w+\))?:(\s\w+|)[ :]+(\w+|)/i', $resposta, $output) == 0) {
    echo 'Nenhuma informação encontrada';
} else {
    print_r(array_map(null, ...$output));
}