How to disable transcoding?

you need PMP that has a home theatre type “TV” mode

PMP has 2 different modes, a windows desktop like mode, and a full screen HT type TV mode. (use arrow keys to navigate)

I think you may have to be in HT mode in order to access some of the advanced pass through settings.

Unfortunately I dont’ use it so I can’t tell you exactly how, but some searching around will probably help you.