First, I'd like to try sharpening an older video (hoping there's a filter(s) I can try) to hopefully remove some of the pixelation.
Second, the Filters option is greyed out. I'm using 2.7
Filters imply that you reencode the video. This is why they are greyed out if you don't.
It appeared after reencoding, thanks!
No, not after. Just choose any other encoder than "Copy" from the dropdown list of video codecs to get immediate access to all the things like filters which are not applicable in copy mode.
Oh, got it thanks again!