DVD makes everything soooo Dark....professional standards etc....

I took my avi file, encoded it as mpeg 2 and it all came out pretty dark overall....it was properly exposed, its just the overall encode that seemed to do it.

The file was only like 8gb and I couldn't seem to get it to be much bigger than 2, obviously the mpeg file will be much smaller but how can I increase this file so that it comes out as like 3.5 Gb or so?

I am finished editing a surf video/documentary, possibly destined for tv as well, I don't know what to do aside from setting the levels blacks 18, whites 235 to comply with broadcast standards. is there something i'm missing, like a standard setting for the hue, brightness levels or what?

I'm really confused, I have a very good surf video but I can't seem to make it look good once its on the tv....i've seen other surf videos on the market that I know for a fact were shot with lesser cameras than a dvx100 but the overall image quality is much better in these other videos...i' have a feeling i'm really missing something in the editing department that is an important part of creating a professional product.

cheers,

tyler