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 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 following field or frame, and wherein a respective correlation surface is generated for 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 shape of that part of the correlation surface which represents differences less than a threshold level is determined, and the comparison is varied in dependence on the shape.

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, and wherein a correlation surface is generated for each block in the first field or frame, the correlation surface representing the difference between the content of the first 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; it is determined whether the correlation surface contains a clear minimum value of the difference by determining whether the minimum difference represented by the correlation surface differs from the next smallest difference represented by the correlation surface by more than a predetermined amount.

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 succeeding field or frame of the video signal for deriving motion vectors representing the motion of the contact of respective blocks between the first field or frame and the following field or frame, and wherein a correlation surface is generated for each block 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 magnitudes of the differences represented by the correlation surface are weighted if a preliminary determination of the correlation surface fails to reveal a clear minimum difference.

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, and wherein a correlation surface is generated for each block 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; it is determined whether the correlation surface contains a clear minimum value of the difference by determining whether the differences represented by the correlation surface increase monotonically in a region of the correlation surface surrounding the minimum difference represented by the correlation surface.

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: 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: A clock signal multiplexer for combining a plurality n of input clock signals of the same frequency but differing phases into a single channel, by selectively passing one of the n input clock signals to an output of the multiplexer to the exclusion of the other n-1 input clock signals, includes n input circuits to each of which a respective one of the n input signals is supplied together with a respective clock enable signal, a logic circuit coupling the input circuits to a signal synchronizer, the logic circuit operating to enable said signal synchronizer in respect of the input clock signal corresponding to that one of the n clock enable signals which is in a select condition, and further operating on return of the one of said clock enable signals to a non-select condition and transition of another of the clock signals to the select condition to disable the signal synchronizer in respect of the previously selected input clock signal, and to enable the signal synchronizer in respect of the input clock signal

Abstract: A video replay store for a multi-channel digital video tape recorder, comprises a respective channel store for each channel, each channel store comprising a plurality of field stores which are written in and read from cyclically, a respective field boundary detector for each channel, each field boundary detector supplying a first pulse in response to each field boundary where an odd field changes to an even field, and a second pulse in response to each field boundary where an even field changes to an odd field, in the off-tape data in the respective channel, and a replay store controller for supplying write requests and read requests in a predetermined sequence to all of the channel stores, the replay store controller stepping on to the next state in the predetermined sequence in response to each first first pulse following a second pulse and each first second pulse following a first pulse.