How to do split-screen on Minecraft PS3?

Do both people need a connected HDMI cable, or does just one player? We tried everything but it won't work, any solutions? I put on the other controller and pressed start and it doesn't do anything. One of the loading screens said something about High Definition mode to do split-screen, any way to enable that mode? Thanks.

Added (1). We tried one cable and it doesn't work what else can we do?

Since you're playing splitscreen, on ONE television, you only need one cable.