Unfortuantely I dont think there is a single util to do this AFAIK the only way to do this is to convert the .mp2 to a stereo .wav, and change the sample rate to 48 Many sound editors will do this, SoundForge definitely does Then import the .wav to SoftEncode, which will make the .ac3 track Several other points: This topic has been discussed several times in this forum, the threads on Lord of the Rings conversion have a more complete outline, or search on SoftEncode The ac3 will be smaller than the .mp2 , and a lot smaller than the .wav If you are doing NTSC, I believe that .mp2 track is not fully up to DVD specification as the only soundtrack, altho will play in many players anyway Jeff