The way most receivers work is that you can select the video source and then independently select the audio source. This won't work if your dvd player is connected to the dvd input because that is also a video input. If your cable is connected to say 'video 1' and you also connect the analog cables from the dvd player to the 'cd' input, then you could select video 1 to view the picture from the cable box and then switch to cd to hear the audio only from the dvd player.