$re = '/\b([0-9]+(?:\.[0-9]+)?) fps\b/m';
$str = '" Stream #0:0(und): Video: h264 (Constrained Baseline) (avc1 / 0x31637661), yuv420p, 480x480 [SAR 1:1 DAR 1:1], 868 kb/s, 29.97 fps, 29.97 tbr, 11988 tbn (default)"
" Stream #0:0: Video: msmpeg4v3 (MP43 / 0x3334504D), yuv420p, 320x240, 744 kb/s, SAR 1:1 DAR 4:3, 29.97 fps, 29.97 tbr, 29.97 tbn"';
preg_match_all($re, $str, $matches, PREG_SET_ORDER, 0);
// Print the entire match result
var_dump($matches);
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for PHP, please visit: http://php.net/manual/en/ref.pcre.php