If you're serious about doing this, then that wpmdb plugin is completely insufficient imo. You need to be scraping file sharing sites and getting actual download links. Otherwise people will go to your website looking for a file, see that it's just a spammy imdb clone and immediately leave. If you take the time to do it right and use actual download links then people are more likely to click your offers and may even share it and come back again.
How would you setup something similar to the sites that ask for a codec that you mentioned? I'm looking for a way to make a site that would actually supply the videos which require a codec but I don't know where to find a way to make something like that.