IMAGE DATA EDITING

An image data editing facility produces a sequence of output image frames. A wipe animation is produced over a sequence of output frames such that an increasing proportion of the output image is derived from a second sequence of frames and a decreasing proportion of the output image is derived from a first sequence of frames, under the control of a moving boundary defined by a wipe animation. The rate of expansion of boundary is controlled with reference to an animation parameter and the animation parameter is derived from processing at least one stored position parameter with reference to a selected animation starting location.