Apologies for my late reporting in - had some beers to drink at a colleague's leaving do.

Stand by for Brain Dump...

Saga Running Times:

Episode I = 133 mins

Episode II = 142 mins

Episode III = 140 mins

Episode IV = 125 mins

Episode V = 127 mins

Episode VI = 135 mins

So, taking a maximum runtime of 145 mins to take into account menu backgrounds, you are looking at an average bitrate of 20Mbps, Maximum 38/40Mbps, with maybe about 200Mb to spare.

The Prequel Trilogy on 1 x BD50 would work out at 415 mins, Average 13.5Mbps, Maximum 38/40Mbps, so probably a little on the low side...

In terms of audio that's based on the German HD Streams uploaded with:

448Kbps DD 5.1 English
224Kbps DD 2.0 Commentary

No matter what, I'm guessing we will need to re-encode the video, because the chances that the HD Streams are to Blu-ray spec are very low.

As I mentioned to Dark Jedi, not only will the crawls have to be converted to English, but so would any shots which featured Alien speech as this was burnt into the video for the German Broadcast. I guess we'd be looking at Splicing in shots from the HV2 uploads to 'fix' any issues with the German HD broadcasts?

Additional Thoughts

If we were to expand this to a BD-50 per title (perhaps not for 'version 1') we could look at adding additional audio streams: Spanish? French?
PCM Isolated Score?
Secondary Picture Track based on Clones Revealed, Sith Revealed, Beginning Star Wars, Building Empire, Returning to Jedi.
There's the option to play with Presentation Graphics for things like trivia tracks, storyboard streams etc.
Is it also worth considering 'bonus discs' which could collate some of the many standard def documentary preservations together?
Even looking at Standard Definition preservations of the Original Trilogy, Blu-ray gives us the option of syncing up all those various audio tracks (even in PCM) without affecting the picture quality - up to 32 audio tracks.

I'll update this post with more thoughts as I think of them!

DVD-BOY