$re = '/.*\/videos\/(.*?mp4).*?(?<= )(\d+)/m';
$str = 'https://videos-a.jwpsrv.com/content/conversions/7kHOkkQa/videos/JajSfbVN-32313922.mp4.m3u8?hdnts=exp=1592315891~acl=*/JajSfbVN-32313922.mp4.m3u8~hmac=d3ca7bd5b233a531cfe242d17d2ea0c0167b41b90fff6459e433700ffc969d69 19
https://videos-a.jwpsrv.com/content/conversions/7kHOkkQa/videos/Qs3xZqcv-32313922.mp4.m3u8?hdnts=exp=1592315940~acl=*/Qs3xZqcv-32313922.mp4.m3u8~hmac=c30e2082bf748a6b4d1621c1d33a95319baa61798775e9da8856041951cf5233 20';
$subst = "$1 $2";
$result = preg_replace($re, $subst, $str);
echo "The result of the substitution is ".$result;
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