They are needed only if the mpegs aren't already DVD spacification compliant (i.e. if you have AVI/WMV/etc, files or mpegs not already 720x480/576 @29.97/25 fps). If they aren't you need: 1) CONVERTING (usually the encoders create a M2V video file and a WAV/MP2/AC3 audio file) 2) AUTHORING (M2V+audio --> VOB set+BUP+IFO) 3) burning Read http://www.afterdawn.com/guides/ and my FAQs. If they are, you need only to perform step 2 and 3.