I finally got rear left and rear right speakers installed to go from a 3.1 setup to a 5.1 setup in my family room. I found a bunch of test and demo videos on Youtube on my Shield TV device, but I realized that my receiver wasn't switching to DD or DTS when playing them, nor could I hear discreet sound intended for either of those two channels.

is this a known limitation, or am I missing a setting somewhere?