Problem with Video / Audio




I have downloaded couple of movies which are using Decoder to be played in my computer, when I burn them by Nero Vision 5, I notice that Audio is behind the Video !!! It is not happening for all the movies that I download and Burn, but for some of them happens, please help me how to resolve this issue. Pentium 4 and 6X DVD burner , Nero Vision is the software and I use an encoder software along with Windows media to watch those compresed movies.

Thank YOU