input level when encoding CD's

[Matt Morgan]

I have a problem with a lot of my CD's. I'm sure this is familiar to a
lot of people-the sound levels don't match. There's always that one CD
that's a lot louder than the others, so you can't put it on mixes,
etc.

It looks like grip's "calculate gain adjustment" (encoding config,
options tab) will be a step to fixing this problem for new tracks.
Right?

And then, what about existing .ogg and .mp3 files? Can I fix them, or
should I just re-rip and re-encode?

Thanks,
Matt