Optical media must be free of dust and defects. There are long discussions about that. As to the HDMI cable try another from your system and see if that helps.
I have recently come across a frustrating problem.
During playback of DVD's or Blu Ray movies. the picture changes from perfect to a elongated distorted colour vision intermitently. It returns to normal after 3-4 minutes but it frustrates me, because it usually happens during the best part of the movies .. haha