Abstract: In order to include a break slot in a broadcast video signal, the signal is first fed through a RAM recorder having a variable delay. Reading of the signal from the RAM recorder is controlled in such a manner that the delay produced by the RAM recorder is reduced from an accumulated value. After the delay has been reduced by a desired amount, reading out of the signal from the RAM recorder is inhibited until the delay has increased again to no more than the accumulated value, thereby to produce a break slot having a duration no more than the reduction of the delay produced by the RAM recorder.

Abstract: In, for example, a motion compensated video standards converter blocks in a first field or frame of a video signal are each compared with a plurality of blocks in the next succeeding field or frame of the video signal for deriving motion vectors representing the motion of the content of respective blocks between the first field or frame and the next field or frame, motion vectors are allocated to each pixel of each field or frame, the allocated motion vectors are checked to identify spurious motion vectors by comparing the allocated motion vectors with motion vectors allocated to adjacent pixels, and spurious motion vectors so identified are replaced by motion vectors allocated to adjacent pixels.

Abstract: In, for example, a motion compensated video standards converter wherein blocks in a first field or frame of a video signal are each compared with a plurality of blocks in the following field or frame of the video signal for deriving motion vectors representing the motion of the content of respective blocks between the first field or frame and the following field or frame, further motion vectors are selected for assignment to those of the blocks for which less than a predetermined plurality of good motion vectors are derived as a result of the comparison, by ranking all the good, non-stationary motion vectors derived for the field or frame in order of frequency of occurrence, and selecting those motion vectors which occur most frequently, unless they fall within a predetermined window of pixel motion of a motion vector already selected.

Abstract: Apparatus for converting a video signal to a photographic film image comprises a television standards converter for deriving from an input video signal, which may be a high definition video signal, a motion compensated digital video signal corresponding to 24 progressive scan frames per second, a video signal recorder for recording the digital video signal, a digital-to-analog converter for converting the digital video signal after reproduction to an analog video signal corresponding to 24 progressive scan frames per second, and an electron beam recorder to which the analog video signal is applied to record the content of the analog video signal on photographic film.

Abstract: In, for example, a motion compensated video standards converter blocks in a first field or frame of a video signal are each compared with a plurality of blocks in the following field or frame of the video signal for deriving motion vectors representing the motion of the content of respective blocks between the first field or frame and the following field or frame, a correlation surface is generated for respective blocks in the first field or frame, the correlation surface representing the difference between the content of the block in the first field or frame and the content of each block in the following field or frame with which it has been compared, the correlation surface is tested for a clear minimum, the size of the blocks is increased to generate new correlation surfaces, each new correlation surface is tested for a clear minimum, and motion vectors are derived in dependence on the clearest minimum so found.

Abstract: Apparatus for generating an image for digital scene simulation, the apparatus comprising a first store for storing address data defining the three-dimensional shape of an object, a second store for storing video data defining the two-dimensional surface detail of the object, a matrix circuit for manipulating the address data to move the object (by translating it, changing its orientation, or both translating it and changing its orientation), a perspective transformation device for perspective tansforming the manipulated address data to form transformed address data defining a two-dimensional image of the object after the manipulation, and a third store in which the video data is written, under control of the transformed address data, in the form of output video data defining a two-dimensional image of the object after the manipulation and with the surface detail.

Abstract: A television standards converter comprises a motion analyzer for analyzing the motion between consecutive fields of an input television signal of one television standard and for deriving motion vectors in dependence on the motion, a filter for recursively filtering the motion vectors, and an interpolator for aligning the fields in dependence on the filtered motion vectors so as effectively to represent static pictures, and means to effect conversion using the static pictures to derive the required output television signal of a different television standard.

Abstract: Apparatus for processing motion vectors associated with a digital television image, comprises a vector filter and a vector calculator for deriving a plurality of motion vectors respectively representing the motion of pixels in a corresponding plurality of blocks of pixels in the image, a processor for distributing the plurality of motion vectors into groups, each group comprising motion vectors lying within a respective different predetermined range of magnitudes and directions, and a processor for substituting for the motion vectors in each of a plurality of the groups into which the largest number of the motion vectors fall, a single motion vector representing the motion vectors in the respective group.

Abstract: A two-dimensional finite impulse response (2D-FIR) filter arrangement includes a 2D-FIR filter (26,30,32,34) operative during each of successive clock periods equal to T (where T is the spacing of digital samples or words of an image signal) to effect filtration over a predetermined area of the image by processing n.times.m words of the signal, having a predetermined spatial relationship in the form of an array, to produce an intermediate word. Some of the intermediate words are stored in a partial products store (28). A controller (60) is responsive to a signal (HCF,VCF) indicating an extent to which the image is to be compressed to do two things. First, it causes the FIR filter (26,30,32,34) to adopt a bandwidth which is reduced, with respect to a value for zero compression, by an extent related to the extent of compression. This reduces or prevents aliasing that otherwise would be caused by the compression operation.

Abstract: A random access memory apparatus suitable for sequential write/non-sequential read, for example in a digital video special effects unit, comprises a write enable demultiplexer and a write address generator for demultiplexing incoming data into N channels A to D, where N is at least two, N memories in each of the N channels A to D, the incoming data allocated to any given one of the channels A to D being written into all of the memories in the given channel A to D, a read address generator for reading stored data from any one of the memories and, on reading from a memory, setting a busy flag for that memory, the busy flag being cleared N data periods later, and a busy flag control to control the read address generator to step onto a different memory in the same channel A to D as a memory to be read, when the memory to be read has a set busy flag. Apparatus is also provided for non-sequential write/sequential read and non-sequential write/non-sequential read.

Abstract: An image signal processing apparatus comprises a memory (12) and an address generator (14) that generates addresses for allocation to successive words of a digital input signal (10) representing an input image for mapping those words (or words obtained by interpolation therefrom) into the memory (12) in such a manner that individual portions of the mapped image stored in the memory may be compressed and/or rotated with respect to corresponding portions of the input image. A digital filter (40) of variable bandwidth effects two-dimensional filtering of the image before it is stored in the memory (12). Local scaling factor computation means (42) monitors the addresses allocated by the address generator (14) to successive sets of words of the input signal corresponding to successive local image areas and computes from each set of addresses, for the corresponding set of words, a local scaling factor representing the extent of compression and/or rotation of the local area.

Abstract: An arrangement which displays an indication of the amplitude level of digital audio signals. The arrangement includes an acquisition means which receives digital audio signals and determines the peak amplitude value of the signals received between successive interrogations by a control means, and at least this value is indicated by a display means. If the currently indicated value exceeds the last determined value, then the indicated value is caused to decay at a predetermined rate.