Check your owner's manual for the YHT-195 (I haven't found it online, yet), but I believe that the following is from the manual and explains your situation (and is an excerpt from this
forum thread):
"Be sure to connect your video components in the same way you connect your video monitor to this unit. For example, if you connect your video monitor to this unit using HDMI or COMPONENT VIDEO connection, connect your video components to this unit using the HDMI or COMPONENT VIDEO connection."
I had suspected this might be it. It seems that your receiver cannot do video conversion. So, if you want to do video switching using the reciever, then you need to connect everything to the receiver using the same type of video connection, and then use that same type of video connection between the receiver and the TV.
If your TV has enough video inputs, you could just use the TV to do the video switching and only do audio switching on the receiver. You could also do some video switching on the TV and some on the receiver, if need be.