Video and Audio effects are hardware or software devices and or programs,  that can manipulate how your video ultimately looks and sounds. Effects can be controlled via a multitude of parameters including rate, feedback or distortion angle to name a few. They are useful as studio tools while recording live audio or video, or in the post production process. A video effect will ultimately enhance the scene by adding to the shot. For example, a graphic could fly into the scene as a starburst.  Audio effects match what you see visually. For example, adding a ’ swoosh ’ to that starbust video effect to enhance it’s presence.  Doing something electronically to a sound, that changes its characteristics or form, to better tell a story. This could include voice overs, music and unique sounds.