I noticed that almost half of the MKV files I convert to ATV 5.1 using VirtualHub result in no audio playback. The files that are successful playback on my Denon receiver as Dolby Digital. The problematic files produce no sound either on my 5.1 HT nor is there any audible sound in stereo on my iMac. I notice that the MKV files that are not converting the sound successfully display AUDIO properties in VLC as DTS audio. Anyway to fix this?