A question I have long wondered about but never been able to find a definite answer to is whether my TV can or should be able to pass DD5.1 audio from HDMI in to SPDIF out. The TV is a Sony KDL-50W670A and it is almost impossible to find this kind of information about it. There are raging arguments on-line about whether this is possible at all for any TV because of HDCP issues. A lot of people also seem to have questions about this so I thought it might be helpful to offer what I have learned.

I can't speak for other TVs or if HDCP has anything to do with it, but I can now state unequivocally that this specific model of Sony only passes 2-channel stereo audio out the optical jack. I have a blu-ray player with a direct optical connection to the amp as well as HDMI out. If I switch inputs while the disk is playing, I switch between DD5.1 and 2-channel stereo. I also have a gadget that has been proven to ignore HDCP and even with that in the circuit the audio via HDMI is still only stereo. Unless there is some secret menu hidden very deep, I can state with confidence that this particular Sony does not pass surround sound through the optical output. This is not to say that you can't get 5.1 audio output if you are receiving a DD signal through the tuner.