I tried ripping a few of my old DVD's to Mp4/AVI using the latest 126.96.36.199 beta.. They contain mono-sound but the ripper seems to encode them to stereo which I believe is quite a waste of space.Seems like a bug that needs to be fixed(?)
In the current version, DVDFab mobile not support output mono channel, in all profile, the audio will be convert to stereo. it is not a bug.
Change the output channels will be added in the future.