dvds with redundant video files...?

[spiritgumm]

I know sometimes a dvd is authored so video files appear twice so it appears larger than it is (in Dvdshrink). But there are some retail dvds (specifically from Olive Films) that seem to actually add a large video file already present in the main film. Vobblanker doesnt show the large file as being "reused" but is actually another video file. When I blank it out, the dvd size drops below 4 gigs, but the movie is completely intact. Dvddecrypter indicates the retail disc is duallayer, and the PC shows it being over a DVD5 size. I'm just perplexed why they would waste a duallayer disc to inflate the video size unnecessarily. Or am I missing something, and somehow the extra video adds to the quality somehow?

[jman98]

DVDs can sometimes appear larger than they are due to multiple-angle videos, but this is also done via bad sectors as a copy protection mechanism (ie. ARCCOS and similar protection schemes). I have run into exactly what you are talking about a few times although I know nothing about Olive Films. My best guess is that just like the American consumer is convinced that 5.1 is "better" even if the original audio was mono, a significant portion of consumers associate low quality with DVD-5 releases. So I believe that some films have phone VOBs in them simply to get them up to DVD-9 size. The production house may have been too lazy to re-encode the video with a higher bit rate for DVD-9 so they just dump phony VOBs in the disc to get it up into a DVD-9. It could also be a copy protection mechanism as the squeezing program may waste valuable bits re-encoding the dummy VOBs and they hope that the movie will shrink down enough to be considered of poor quality to the re-encoding person.