i have been using vob2audio to rip the audio only. everything has been working great until i tried u571 i keep getting a missing audio stream error then it say to use the audiovob only feature in smart-ripper. the only difference with u571 is that this is the first dvd i have tried that also has a dts audio track. could this be causing the problem. what does it mean by audiovob only in smart-ripper. thank you