(1) In waveform audio, sound that is played back at a different rate, directed by another application, to create a special effect - created by skipping samples rather than changing the sample rate. (2) The point at which video playback is no longer smooth and appears jerky due to missed frames. This is determined by the size of the playback window and the power of the processor. The first time you view a video clip on your computer, the software - normally Video for Windows - will analyse the speed of your computer and will work out the playback rate that it should use to display video action that appears smooth.