Bunchofstuff

ok.. i have some unencryped vob files on my hard drive and some of them will fit onto a dvd , but when i try to use nero make or modify dvd fuction to burn them they are to big, and the i use the convert dvds to nero digital fuction to make them smaller , and when i burn it to a dvd the sound doesnt match the video , any help? or other techniques... also , is there a way if you have a vob file less than 4.7gb to burn it to a disc and play it on a dvd player? thanks