How to determine bitrate

[beartums]

I'm making a multi angle dvd. I know the bitrates of each stream have to be lower than a single-angle DVD. But how do I determine what that bit rate should be?

I assumed that since the max bitrate is 9.8, I would have to make sure that each stream was aroung 3, but when I encoded using TMPGEnc, I found that 2 pass VBR at 2K min, 7K avg, and 8K max worked fine for three angles on one DVD. That didn't make sense, but since I was able to burn it (using dvd maestro) and play it in multiple players, I assumed that for some reason the encoding used lower bit rates than I had specified.

On another DVD, the 2K, 7K, and 8K settings didn't work, but changing then to 2K, 6K, and 7K did. The DVD wasn't that different -- both are martial arts tests. The second one was a bit darker than the first, but the same cameras, capture devices, etc were used.

My Questions: How do I determine beforehand what I should set my bitrate settings to in order to handle multi-angle DVDs (so I don't have to just reencode each time, using trial and error)? How do I deterimine what the ACTUAL bitrate of a stream is? Why are bitrate settings so high working for multi-angle?

Ideally, I'd like to be able to determine all of this so that eventually I can be more specific in my bitrate settings (maybe angles 1 and 2 at a higher bitrate and angle three at a lower one), but I'm afraid at this point it just doesn't make much sense to me.

thanks,
e

[andkiich]

I'd think that if you put the total time of all the angles together and use that as the base for your calculation in a bitrate calculator you would be OK.

Example:

Main movie and 2 angles each an hour = 3 hours. Plug that into the bitrate calculator and use that bitrate.

[beartums]

Thanks for the comment, but I don't think that's going work. As I understand it, the bitrate calculators can make sure my stream is small enough to fit on the DVD, but that's not the problem. My stream is only 20 minutes long X 3 angles is only 60 minutes. The bitrate calculators will maximize my bitrate at 8K because it will try to give me the best quality that will still fit an hour onto my DVD. But three 8K angles will not make a compliant DVD because they are each taking up some of the total bitrate at every point in time -- and the maximum bitrate for any point in the dvd is 9.8K, I believe (including audio)

Maybe I'm wrong, but this is as I understand it. Can someone clarify?

thanks,
e