poor contact with Apple TV

I have an Apple TV which works super with our other Apple units (iPads and iPhones), but suddenly won't talk properly with my MacBook Pro 13" Retina, OSX Yosemite 10.10.3..

It started out excellently and worked very well for a few months, but suddenly the contact between MacBook and Apple TV has turned very poor. Movies (both sound and picture) sort of "pulsates" rhythmically with 1, maybe 2 seconds frequency, between which picture is frozen and sound is quiet. Please note, that it all started our perfectly, so there can't be any type of technical mismatch between the two units!

An advice anyone, please?