Abstract: To alleviate problems experienced with field rate unconversion, a high definition source is field rate upconverted prior to bandwidth compression. Bandwidth compression is performed by a number of different methods, at least one of which is applied to the upconverted source signal. The branch or method of bandwidth compression transmission is selected in accordance with a control signal responsive to picture content. Prior to transmission of the upconverted bandwidth compressed signal, the signal is collapsed to the transmission field rate and the samples rearranged into a quincunxial configuration.

Abstract: A video signal received from a source (10) is bandwidth-compressed by filters (12, 14, 16), filter (14) being a temporal filter and filter (16) being a spatial filter. Selection of the filter to be used is dependent upon picture content. The transmitter reconstitutes in interpolators (44, 46) the signal which would be regenerated at the receiver, determines which filter gives the best results, and transmits an indication of which filter has been used in a digital signal associated with the analogue video signal. Preferably a determination of motion vectors associated with the signal is made and the digital signal indicates which of the determined motion vectors is applicable to different areas of the picture. By transmitting the control signal digitally with the analogue video signal the receiver circuitry is greatly simplified while its reliability is improved.

Abstract: Video signals (Y,U,V) from a telecine machine are accompanied by a blemish signal (D) (obtained for example by infra-red scanning of a color film) indicating the presence of scratches, dirt etc. This controls a switch (22) to substitute information from another part of the film (e.g. the previous frame, from a frame store 33). To prevent substitution with information also containing blemishes, the blemish signal in respect of the substitute information is made available (flag store 36) to suppress the substitution and switch to an alternative source such as a interpolator (31). The use of a movement detector, (not shown) to suppress substitution from another frame when motion occurs, is also described. The circuitry can be adapted for use in conjunction with a videotape dropout detector.

Abstract: In a telecine apparatus having a film transport mechanism for moving a film at a nominally constant speed and including a motor driving a capstan around which the film passes, there is a sensor for line-by-line scanning of the film to provide a raster-scanned electrical output signal representative of the film image. Also included is a scan control and a film speed measuring device coupled to the capstan to provide an output representative of the instantaneous film speed. A compensating device connects the output of the film speed measuring device to an input of the scan control such that the scan time of a particular line scanned by the sensor is varied to compensate for fluctuations in the film speed.