Ps3 & ps4

So for my husband's birthday I bought him a PS four and a new 42 inch Visio TV he already had a PS3 and the Visio TV has two HDMI outlet one is taken up by our DirecTV so I have a regular's litter to put both game consuls into and hook it into the second HDMI slot we have on our tv. When I do that I can't get either game machine to show up on the TV is there something I'm doing wrong something I need to do different particular kind a splitter I need but I don't want him to have to get up and swap out a quart each time he wants to play different console