Where are the extra 2.5GB on "Are we there yet?"

[AlainDelon]

This movie was authored by Sony but i have seen this phenomenon a few other times:The ISO/image of this dvd is about 7.5GB but the VIDEO_TS folder is only about 5GB.There is a 4mb game visible in the ISO but what takes up the remaining 2.5GB?Are there files not visible to windows or some other explanation?

[LIGHTNING UK!]

Nothing really, they just pad the image out so that the data is on the outer parts of the disc - for higher transfer rates.