I always record in 1920×1080 29.97 interlaced AVCHD video (Sony). My most common delivery is decent quality web, like blip.tv. So I set my project to an HDV setting of very high quality. This will end up being one render to 1280×720. If I need a version for DVD, I put me HDV video from the first render into a project setup for DVD, 720×480 1.2121 pixel aspect. This is render number 2. If I need a copy for a mobile device such as an ipod I put my first render into a project template for ipod and render again.
Whenever I render to a DVD I always use 2-pass VBR and I use a bitrate calculator to really tweak the setting to get the best quality I can.
Don’t worry about render times. It goes with the territory. I am blessed to have an i7 3.2 with 24GB and twin GTX-460’s, the two video cards help because Windows 7 offloads some math to the GPU’s regardless of the OS.
With the first render you do all the color correction and effects, then when you re-render it all that extra processing is done, all that must be accomplished is the resizing. You cannot size up from say 720 to 1920 it will look terrible.
Most people would only render from original footage, but I am not one of them. In that case, re-save your original project with a descriptive name and then change your project settings. Make sure the aspect ratios are all good.
These are just some thought on your problems. I hope it helps.
As far as the 5.1 goes, you must have 5.1 to produce 5.1. You can’t just put stereo through the 5.1 setting and expect too much. But I’m sure you already know that.
Jeff
http://www.narrowroadmedia.com