Re: Bitrate

Steve, here's what John Rofrano had to say about bitrates in the Rendering 2 hour video to DVD....understanding bitrates thread.
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The Average bitrate is what's important to file size. It determines what the overall average for the entire file will be. The Maximum bitrate says that you can go up to that if you need it but you must steal from other frames later to maintain the average. The Minimum bitrate is just a floor to not go below.

When you start dealing with lower bitrates you can sometimes get better quality by using the 2-pass option. this takes twice as long to render because it makes one pass to determine the bitrate it needs for each frame, then it plans where it wants to use the bits that it has available based on the need and makes a 2nd pass to do execute the plan and do the actual encoding. This way you get maximum utilization from your "bit budget".
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I use a bitrate calculator for anything I do that's over 70 min. in length for the simple reason that I find the stock templates far too lenient and I want to get the maximum quality possible.
For example, the DVD Architect NTSC video stream template in Vegas uses a VBR setting of 9,500,000 / 6,000,000 / 192,000.
By way of comparison, Mark's Bitrate Calculator gives me a VBR of 7,904,000 / 6,320,000 / 3,792,000.
BTW, if my numbers are different than yours, it's because I bumped my safety margin up to 5% from whatever the default was (1%?).
As I've said earlier (and it's been repeated by a number of users a lot smarter than I am abouth this), never exceed a Maximum bitrate of 8,000,000 as this may cause problems with cheap media and/or the DVD player.
With Mark's calculator, the Average bitrate as well as the Minimum are higher which translates to a better quality picture.

Sorry for the long response but hopefully this explains why I do what I do.