Why aren't movies encoded to fill the full capacity of the optical disc?

[lingyi]

I don't know how common this is with Western releases, but many Asian releases fall far short of the full capacity of the DVDs / Blu-Rays. It's especially annoying when a DL disc is used and movie/extras are just over the size of a SL disc. And it's not just because that's the size of the encode, because sometimes the same contents are released on a bargain SL disc, encoded to a smaller size to fit.

Considering the studios are typically starting with 2Tb+ masters, why not encode to full disc capacity (less space needed for extras). I may be missing something, but since the capacity is there and the discs are pressed, I don't see any cost advantage. Also, it's really annoying to see 2Gb menus which I'll ignore anyway since I always remux Blu-Rays to .mkv . I don't have a standalone Blu-Ray player and generally skip DVD menus anyway. I hate waiting 30 seconds for an animated menu to load!

[Cornucopia]

Lingyi,
Here's the way it likely plays out in most H'wood studio-related authoring houses:

A title is acquired and slated for release.
A list of expected assets is generated, based on intended design of the whole package, including the main title, the outtakes and making-of clips, the menus, etc. And a bitbudget is created to fit those available assets on the planned media size (which is determined by expected demand).
Since this a for-profit business, and factory atmosphere, existing bit templates are often re-used, and time is probably too precious to set up a 2pass for encoding a 2nd time. So the expected bitrates are set and fixed early.
Then, if the assets change due to contractual maneuvering, items which shrink/are removed, stay shrunk, and items which grow either spill over to larger disc capacity size (when in high demand) or the asset list is renegotiated to be less, so it is again shrunk.

Scott