If I have a 700MB video file and A 4.7GB DVD, why can I only burn 1 video? What takes up the other 4GB on the disc? or is there a way to burn multiple videos to one DVD that can be played in any dvd player?

I'm sorry I just don't understand...

This link should set you straight....

http://www.dvd-guides.com/content/view/46/59/Thanx. Seems like a descent tutorial. I'm just wondering how much video I can actually put on one now THOUGH. I have infrarecorder and it let me add 7 movies before the disc was full but i guess i didnt make an ISO or something and it wouldn't burn. I don't really understand it but I'm just trying to fit as much as I can so I don't waste discs.An average .avi file is about 700MB, so, if you copy those files into DVD, you can fit 6 movies, but if you burn .avi file into DVD format (.VOB), then you can fit only 1 movie and you have about 30 minutes of a free SPACE left.
700MB .avi (90 minutes movie) = ~3.5GB in .VOB format (90 minutes)I see... but can I SOMEHOW lower the quality of the .VOB file? We used to have one of the sonic suites or some sonic software and there were DIFFERENT quailty options. I never picked the lowest but they had like VHS quality. I would probably be able to fit a LITTLE more on there. Unfortunately my friend got a virus on that computer and theres is no more sonic. Can DVD shrink do this or what?There are many burning programs, which will shrink movie size, but it'll obviously lower the quality. Don't expect to fit 6 movies into one DVD and have those movies readable.
DVD Shrink has compression options: http://www.afterdawn.com/guides/archive/how_to_copy_dvd_with_dvd_shrink_page_3.cfm
You may get better reply, if you tell us, what exactly you're trying to achieve.