HDMI ARC port is meant for tv connection and other two input port meant for dth/ any other hdmi devices. But the real issue is if i connect adtv box to HDMI 1/2 it has to be selected each time. Means first in tv i have to switch input to hdmi 1 in tv then in sony ht again hdmi 1/2 then it will take a settlement time. That too heavy. In this scenario there wont be any sync issues. But if we connect the ADTV box directly to TV and then tv supplies audio to SONY HT the process is smooth but audio video will be out of sync. You can override this by connecting optical audio from ADTV box to HT box there wont be any lag in audio video sync. But there is no optical out in this version of ADTV xtream box .