judder

A temporal artifact associated with moving images, which artifact occurs when the image is sampled at one frame rate and converted to a different frame rate for display; as a result, motion vectors in the display may appear to represent continuously varying velocities. Note: The subjective effect of the artifact becomes more obvious when the frame-rate conversion is made by simple deletions or repetitions of selected frames (or fields). It may become less obvious when interpolated frames (or fields) are generated by using predictive algorithms.