As mentoned earlier, you can do it with elgato products. The elgato hybrid can de found on ebay under $100. If you buy used make sure they include the tuner software. The only bad thing is that the device only supports S-Video in, so not high def like it appears you want.
My cable provider uses HDCP on the HDMI. When I tried to connect my setup box to my older reciver with HDMI switching, I got a message that this device is not HDCP compliant.