Parts of the painted stripes on my deck have a sort of white film on them. It seems like it has oxidized. It is also a bit rough to the touch.
I used some regular wax, but it didn't help.
What can I use to bring back the brilliant color?

Wizzards "Turbo Cut" You can get is online or at alot of parts stores. Nice stuff to work with.

It is hard to say without actually looking at it , but it sounds to me like you should try colorsanding and buffing it, then waxing it to reseal it!

Sounds to me like the clear has deteriorated and needs to be sanded down and repainted and recleared