I am looking for a switch to instantly choose between two HDMI sources (both 1080p60) and display the chosen feed as the output to another HDMI port. The important part, however, is that the switching must occur instantly and can't cause the inactive source to setup the HDMI connection from scratch when it becomes the active source.
At the moment, I have a "dumb" HDMI switch that, when pressed, toggles between the left and right HDMI input by directly routing its wires from the input to the output, the equivalent of unplugging one cable and plugging the other cable in. The problem is that the inactive device was essentially unplugged, and then had to initialize a brand new connection (if it's a laptop for example, it has to change screen resolutions, and then perform the necessary HDMI negotiation), which is visible and takes about a second.
I am looking for a device that will constantly read the source HDMI feeds so that the devices believe they are always sending video (regardless of whether it's active or not). It also needs to switch gracefully between frames from either source, not causing any visual artifacts from transitioning mid-frame.
The device should support 1080p video (preferably at 60Hz) with minimal or no visual degradation. Two inputs are needed, but having more isn't a problem (unless it's impossible to instantly switch between 1 and 2 because it has to toggle through the series).