Blu-Ray Fit Contents to available space

Question

I made my first blu-ray disc in PreEl, and I tried to add as many raw video clips exported from my Canon Vixia HF200 as would fit on the disc.  On the Share->Blu-Ray settings, it said the space required was 22.89 GB, and I then checked the "Fit Contents to available space" box, which changed the Space Required to 23.30 GB.  The disc came out ok, but I discovered there was about 7GB left unused, and it is visually obvious the burner didn't use the last 1/2 inch or so of space on the bottom of the disc.
Is there a better way to try to utilize all the available disc space?  In this case, my goal is to archive as many original video files as possible onto a disc.  However, I have tried to group them together and add menu markers to them, so I don't end up with 200+ chapters on the disc.
I plan to actually edit and create videos more in the future, but for now I'm thinking in terms of getting many hours ofHD video off my hard drive and making multiple backup copies to blu-ray discs.

Answer 1

Neale,
Unless things have changed, and this could be by version, or a difference between BD and DVD-Video, PrE uses a 2-Pass VBR Transcoding scheme. What this means is that PrE measures what it thinks the size will be, then runs the first pass. This pass basically samples the motion in the Timeline, and stores data to be used in the next pass. Then, on the second pass, that info is used to assign a higher Bit-Rate to areas of high motion, and lower Bit-Rate to areas of less motion. It is not until PrE is completely done with the second pass, that it knows for sure, how large the file will be, as the Bit-Rates will be altered, as needed throughout the process.
The multi-pass Transcoding is how Hollywood crams so much high-quality material onto a DVD, or BD. There Transcoding software will do maybe 9-Passes, or even more, and then the operator can tweak things as required. This results in a variable Bit-Rate that is the ultimate for every segment of the Timeline - not 1 MB/s more than is needed, and very high motion at the best possible Bit-Rate to keep that smooth. Never too much, and never too little. Sort of a Goldie Locks situation, and run by highly-trained professionals, who do nothing else all day long, using software that costs more than a Mercedes E-Class.
As for the BD-Data, one is not Transcoding to produce that. If there is any Transcoding, it would first be done by the user, and then the resultant files would just be Copied over to the BD-Data disc. As you say, one would calculate the number of files, times their size, and subtract that from the capacity, adding more, or subtracting some, to fill the BD-Data.
Hunt