Are some blu ray's already compressed?

[stinkfinger]

Backed up my copy of The Aviator last night. Was expecting to take quite a while to compress since the movie is 2:45 long. However no compression was needed. In fact the movie was less than 22GB once special features were taken off. Copied just fine. I'd watched the movie a couple times and picture quality seemed good. Are some movies compressed at the factory?

[Complication]

All movies are compressed, BD or DVD. However, they usually use professional tools that take lots of time to get the compression just right. Sometimes that takes up most of the disc, sometimes less than half. Depends on the movie and the attention to detail of the disc author.