Abstract: A digital video effects apparatus is arranged to generate a digital video effect by interpolating the values of parameters governing the effect, according to a given function, between time points corresponding to selected frames of a video signal and at which the parameters are fixed at selected values. The apparatus is organised in such a manner that the values of parameters are stored in exclusive timelines enabling the time points at which the parameter values are fixed to be adjusted without reference to other parameters governing the same video effect.

Abstract: In the processing of digital video signals there is provided in association with each signal an accompanying tally signal which provides an instantaneous identification of one or more signal sources from which the information contained in each pixel of a picture image has originated. The format of the tally signal may enable processing thereof to identify all signal sources contributing to a particular image area, to pixels of a mixed image or to any given field or frame of a video image signal. The signal may be encoded in the format of the digital chrominance signal component of a color picture signal and combined with a conventional key signal which is encoded in the format of a digital luminance signal so that the combined signal has the format of a color picture signal.

Abstract: A cabinet for electronic equipment comprises an array of printed circuit boards stacked in horizontal planes. The circuit boards are interconnected by a vertically extending rear mother board, and the cabinet includes a plenum chamber defined by a partition having a plurality of vertically arrayed ventilation openings through which air can be drawn from the lateral spaces between the circuit boards and exhausted from the rear of the cabinet by a blower.

Abstract: A digital divider for forming the quotient (Q) of two numbers (A,B) includes means providing values (Q+1, Q-1) of the quotient with possible rounding errors added to or subtracted therefrom.

Abstract: In a digital video effects system having a store (8) wherein coordinate values are stored in curved order by addressing the store with coordinate values transformed by a function generator (1) and transformer (2) and storing linear values derived from counters (6), the resolution of incremental values from the transformer (2) is increased as necessary to avoid unwritten addresses in the store by providing, between the transformer (2) and the store (8), delay means (3) for providing coordinates of the corners of adjacent quadrilateral areas defined by integer values of the transformed coordinates, a "predisector" (4) for providing coordinates of smaller quadrilateral areas into which the first areas can be divided, and a "hole filler" (5) for generating intermediate coordinate values failing within each smaller quadrilateral. An interpolator (7) serves to provide intermediate data values derived from the linear values to match the intermediate coordinate values generated by the hole filler.

Abstract: A video image processing system includes a decay processor provided in a signal path via which a video key signal is recirculated through a frame store. The decay processor includes a selector switch for determining which of a plurality of signal paths having different signal modifying characteristics is included in the recirculation path. The selector switch is controlled by a pseudo random sequence generator, thus providing novel visual effects.

Abstract: In a digital video effects system a data store (13) is provided for storing the address within a frame store of image information from the corresponding image frame that is to appear within another image frame as transposed on to a curved surface. The addresses are stored in "curved" order so that when the store (13) is addressed via inputs (24) providing the coordinates of the scanning point of the television raster, the store (13) provides, at an output (25) that address within the frame store which contains the image information to be represented at the corresponding point in the final image. Such storage of the address values in "curved" order is achieved by applying at data inputs of the store a linear sequence of the coordinate addresses of the image frame store whilst providing at write addresses (11, 12) of the store data (13) corresponding values of the coordinates that have been transformed to define the curved surface to appear in the final image.

Abstract: A system enabling a digital video signal to be recorded and reproduced utilizing a solid state memory store (1) as the recording medium comprises a plurality of random access memory sub-systems (1A-1D) each incorporating a read/write buffer (2). The buffers (2) are connected in parallel to a common video data bus (3) and addressing and control inputs of the subsystems (1A-1D) are connected in parallel to a common control bus (5). One or more read/write sub-systems (6) are arranged to receive and/or output digital video signals in real time via an input (10) or output (11), such signals being transfered to and/or from the store (1) via a corresponding buffer (7; 9) coupled to the data bus (3). The capacity of the buffers (2, 7, 9) and the data bus (3) is a multiple of that of the input (10) or output (11) so that each read/write system (6) can transfer accumulated data at a slower rate than it is received or output.

Abstract: Deterioration of the image as a result of failure of individual memory cells is avoided by storing, together with the data relating to each line of the image field, a code value computed as a function of the value of each data bit in the line and the position of each bit in the line. A picture signal stored in this way may be reproduced by transmitting each line signal to a function generator (15), adder (16) and accumulator (17) to re-compute a code value by the same function utilized during the storage of the signal, and applying the stored code value to a latch (21). The outputs of the accumulator (17) and latch (21) are applied to a subtracting circuit (25), and when the latter produces any output signal other than zero, the value of such signal will indicate both the position of any single faulty bit and the direction in which the stored value is in error.

Abstract: A control signal synchronized to a digital video signal to be processed and defining the position of a rectilinear line (51,52,53,54) relatively to the image frame (50) is generated by providing an initial value corresponding to the perpendicular distance of the origin (0) of the scanning point of the video raster from the line (51,52,53,54) and incrementing or decrementing this value during movement of the scanning point in accordance with the rates of change of this distance in the horizontal and vertical directions. By logically combining the signals corresponding to a plurality of lines (52,52,53,54) a further signal is obtained which is "true" when the scanning point is within a geometric figure defined by the lines. This signal can provide a "key" signal controlling the display within the figure of image information to be combined with the video signal.

Abstract: A video image processing system for generating so-called "multi-freeze" digital video effects comprises a frame store (14) within which an image signal can be stored for application to a combining circuit (4) together with a background image signal (1) providing a background against which a trail of frozen images is to be displayed. The trail of images is derived by recycling images stored in the memory (14) through a further combining circuit (19) wherein the stored image is combined with incoming image signals applied to both combining means (4,19). Decay and patterning of the frozen images can be effected by circuits (24,25) for attenuating and profiling the key signals accompanying the image signals.

Abstract: In a method of processing a video signal to provide digital video effects, an image signal is provided with an accompanying reference signal or Z-axis signal representative of the instantaneous distance of the scanning point of the video raster from an imaginary plane to be depicted as containing said information, taken in a direction perpendicular to the image screen. This reference signal may then be utilized to produce a variety of effects. For example a circuit for superimposing sets of image information to give the impression of an overlap in three dimensional space may comprise an order sorting circuit (1) having inputs (2,3,4) for sets of signals comprising picture information (P) a key signal (K) and a Z-axis signal (Z). At outputs (5,6,7) of the circuit the sets of signals are sorted into order of priority dependent on the magnitude of the Z-axis signal (Z).

Abstract: A storage and interpolation device for digital television pictures having a memory organized in `tiles` of memory elements (2). Sub-assemblies of tiles (2A, 2B, 2C, 2D) all have the same coordinate address in one coordinate direction and have outputs coupled to an interpolation filter (6) operative in that direction. Individual tiles (2A; 2B; 2C; 2D) of respective sub-assemblies (1A, 1B, 1C, 1D) all have the same coordinate address in the other coordinate direction and the outputs of the filters (6) of the sub-assemblies are connected to inputs of a further filter (9) operative in the other coordinate direction. By allocating pixel values of discrete image areas of the picture to respective sub-assemblies (1A, 1B, 1C, 1D) in the horizontal direction and to groups of tiles (2A, 2B, 2C, 2D) in the vertical direction, interpolation can be effected by addressing all tiles simultaneously to produce a corresponding output from the filter 9.