Digital audio refers to representing sound numerically by decomposing analogue sound waves into samples. This differs from analogue media like tapes which store sound physically. Interactive features in digital publications allow two-way communication, like responding to instructions from the user to pause, rewind or fast forward content. They present audio, visual, text and other media content that responds to user actions. While video and graphics provide visual aids, disadvantages include potential poor quality, digression from text, and some graphics not adding useful information.