Show warning for subtitles that are 9:59:59.99 long

[SmoothStoinkleSunnySun]

Hello lovely people keeping this lovely program nice and tidy,

When a subtitle is 9:59:59.99 long, the program attempts to convert it and will always fail (on 24gb of ram) because it runs out of memory to use. Could a warning pop up before you attempt to convert a .ass with an extremely long-lasting subtitle? I tumbled upon this problem when I foolishly entered 999999 on my keyboard to make the last subtitle of a video to last until the end of the video.

Have a nice summer :)