Why do I get a strange noise trying to watch a dvd through HDMI? Was fine, only started yesterday.?

The picture is ok but there's just this constant horrible noise like a huge dragonfly hovering right next to you. I know its not the hdmi lead as I tried a new one. Both picture and sound are fine when watching via scart. This means there must be something wrong with the hdmi input on either the TV or the dvd recorder. But what? Any suggestions please?