File Sizes

I usually burn files i want to watch on my DVD player as VCD files but the problem is i can only fit 700MB onto these disc so i was going to convert the files to DVD files and burn to DVD disc’s which hold over 4gb but the thing i cant work out is after converting them and going to burn them, 250MB files are taking up over 1gb of space going by the counter along the bottom of the screen when using Nero, why is this?

I can’t fit anymore onto DVD as i do to a normal 700mb CD-R.

See this tutorial for how to convert vcd files to dvd.