1)From what I read in several forums, when you use Subler's OPTIMIZE function, it does not really effect the sound quality as the sound comes out of say, HB, it seems it makes sure of the order of some flags or atoms, and by interleaving it may speed up the reading of the sound track ???? 2) when I encode with HB or MDRP, the surround track is present but unchecked as if it doesnt count. When you play the .MV4 file however on ATV it seems ok. I am pretty familiar with the different mix down combinations and I read the results with mediainfo which will show the 2 channel ACC track and the 6 CH AC track in detail, so I know it is there. What happens by checking the unchecked surround track in subler?? 3)I like the abilities of Subler to painlessly look up and ad art, but have to confess I am a basic user. I read about adding/importing tracks, it doesnt seem I have much need to do that???? Sorry for the long windiness of these questions. Finding the exact answers have proven difficult. I have a Mac system, with great speakers and a decent modern receiver with optical and HDMI inputs. I put the movies on an iPad and use air play to watch the movies. Any input would be helpful. Thanks in advance.