[quote]Also, the THX demo, though of good quality, is windowboxed. I have no idea why anyone would master this in 16x9 and not zoom it.[/quote]
Blame THX. They're the ones who made that bizarre encode. I used it exactly as they did.
There's no real reason for a video bitrate to hover around 9 all the time, with a good encoder really doing its work, a bitrate of 4, 5 or even 3.6 is great.