Abstract: Given two video sequences, a composite video sequence can be generated (15) which includes visual elements from each of the given sequences, suitably synchronized (11) and represented in a chosen focal plane. A composite video sequence can be made also by similarly combining a video sequence with an audio sequence. In the composite video sequence, contestants, action figures or objects can be shown against a common background (12) even if the given video sequences differ as to background, with the common background taken from one or the other of the given sequences, for example. Alternatively, a different suitable background can be used, e.g. as derived from the given video sequences, as obtained from another video sequence or image, or as otherwise synthesized.

Abstract: Quantization noise in oversampled digital data can be reduced by processing including alternate steps of lowpass filtering and so-called code projection, in cases where the set of discrete-time signals corresponding to quantized-signal data is a convex set. Corresponding specific methods are disclosed for simple analog-to-digital conversion, "dithered" analog-to-digital conversion, and first- and second-order single-path .SIGMA..DELTA.-conversion. For example, in the case of simple analog-to-digital conversion, code projection involves replacing sample values by quantization-threshold values in those cases where, after filtering, a sample value lies in a different quantization interval as compared with the corresponding value of quantized-signal data.

Abstract: In a digital TV broadcast system, an embedded multiresolution scheme implementing joint source/channel coding is employed to offer at least relatively fine and relatively coarse resolution services. The relatively fine resolution service is intended for receivers within a first radius of a TV signal transmitter and the relatively coarse resolution service is intended for receivers between the first radius and a second, longer radius thereof. Video signals broadcast from the transmitter represent individual signal points which are selected from a signal constellation. The latter comprises signal-point groups each including a multiplicity of the signal points. The selected signal points represent video images in the relatively fine resolution, while the signal-point groups from which the selected signal points originate represent the relatively coarse version of the images.