First of all, you need to make sure you have purchased a license for the "Plus MPEG2 Edition" and have registered the program since the "Plus Edition" does not support video file formats MPEG2. Then, .mpg format is the extension of the file, MPEG2 is the video compressor, so when you convert it (even if you use MPEG2), the extension if the file will be .mpg, the difference will be in the way the video is compressed.