The Yamaha's video processing is built around a solution from Anchor Bay and not only offers HDMI switching, but upconversion to 1080p as well. After living with it for several weeks, I can't say that I am entirely thrilled with the way the video capabilities are implemented.
It only upconverts 480i/p, and only over analog . When the incoming signal is 1080i/p or 720p, the signal is passed through without processing. On the plus side though, I ran a boatload of tests with resolution patters using both 480i component upconverted to 1080p as well as 1080i signals running directly from the HD DVD version of DVE. In these tests, I noticed no loss of detail with the Yamaha in the video chain when transcoding and/or upconverting component signals to HDMI. But on a more subjective note, I did notice that my cable feed (Comcast) was slightly sharper with my Denon upconverting the signal to 1080p than the resulting 1080i passthrough with the Yamaha. I realize that this is very subjective on my part, but my wife noticed the same and mentioned it to me.
from http://ultimateavmag.com/avreceivers/1107yam3800/index1.html