Cell split?

[gulikoza]

Just used DVD Rebuilder for my first backup. I must say it's really an excellent program. I first used DVD Shrink to cut down menues & extras - and the the Rebuilder for the main movie. It came out 4.660.000 bytes, I doubt I could do much better myself :). Now I'm still getting used to all the options...I feel like I could get perhaps a bit better quality when manually tweaking CCE parameters, but that could be just a feeling. Of course, reauthoring and reencoding the extras would take a whole lot longer...
The question here is, why does the movie have to be split in cells. I do know something about dvd format so yes, I understand you cannot just take the normal reencoded CCE file and rebuild the whole dvd structure. But CCE has an option to specify chapter points - this should create cell boundaries at desired location? Or does creating a whole new file actually create the needed header to make everything work again? :D Reencoding the whole movie in a single step (pehaps manually with CCE, only loading the ecl file?) could provide a whole new set of options...

[wmansir]

CCE has an option to specify chapter points

IIRC, CCE Basic does not have that option.

[jptheripper]

its better to split into cells for 2 main reasons.

First, using rb-opt allows you to tweak credits or opening sequences to low bitrates to get higher main movie bitrate.

Second, since the studio already took the time to calculate the bitrate distribution based on the video complexitiy, there is no reason to reinvent the wheel. Using the dyanmically assigned bitrates jdobbs program cleaverly recreates the exsiting distribution, so no advantage is gained.

[gulikoza]

Originally posted by jptheripper
its better to split into cells for 2 main reasons.

First, using rb-opt allows you to tweak credits or opening sequences to low bitrates to get higher main movie bitrate.

Same can be done with Bit allocation in CCE.

Originally posted by jptheripper
Second, since the studio already took the time to calculate the bitrate distribution based on the video complexitiy, there is no reason to reinvent the wheel. Using the dyanmically assigned bitrates jdobbs program cleaverly recreates the exsiting distribution, so no advantage is gained.

I'm not that much of a fan of reduction of bitrate in whole. Don't know, perhaps somebody can disprove me...For an example take a high bitrate scene (6000kbit) and low bitrate scene (1500kbit). If you reduce the bitrate to 67% you will get 4000kbit and 1000kbit for each scene. A total reencode might take more bits from the low bitrate scene without disturbing the picture any more and that would leave more bits for the high bitrate scene...The bitrate curve should be less compressed for lower bitrates.

[jdobbs]

DVD-RB is aimed at giving you all the advantages of CCE without the additional work associated with having to make all those types of decisions.

Your second statement is incorrect. The reencode is still done using VBR -- so it could be just as likely that high bitrate scene may continue to use 6Mbs... if that is what is needed.

[gulikoza]

Not if they are in a different cell. Even if dynamic cell bitrate is selected, the high bitrate cell will still have lower average bitrate. Anyway, DVD Rebuilder is a great proggy...but I would add a third mode (if possible that is) to do a manual main movie reencode - where dvd-rb would calculate average bitrate, write chapter points & ecl file and then accept the produced .m2v before rebuilding the dvd structure...

[jdobbs]

The number of bits available across the entire DVD is fixed... so you have to live within that range no matter what. When you start the encode -- you already have the equivalent of a first pass completed -- because it was done when the original DVD was authored. That means the distribution across cells has already been accomplished based upon the commercial VBR encoding.

All DVD-RB does is then, when reencoding, take advantage of the work that was completed during the original authoring. I've done many, many tests -- you will find that the same general distribution of bits (across the entire movie, not just the cell) occurs when you use this methodology.