Abstract: A method and apparatus for transmitting extended aspect ratio pictures is described. The transmitted pictures can be viewed on an extended aspect ratio high definition screen but can also be viewed on a reduced number of lines on a conventional receiver. The lines not used in the picture viewed on the conventional receiver contain non-visible data relating to picture information. The transmitter comprises a high definition television (HDTV) camera (42) providing a high definition video signal to a standards down-convertor (44). This has a video output with a reduced number of lines coupled to a frame store (46) and a data output connected to a buffer (48). Means (54) combines the data from the buffer (48) with the video signal from the frame store (46). A controller (50) responsive to synchronizing information ensures that the data is combined with blank portions of the video signal. The combined signal is then fed to transmitter (53).

Abstract: In order to achieve increased resolution and to minimise cross-colour and cross-luminance effects in a PAL, NTSC or SECAM encoded signal, a high definition source (20) is pre-filtered at a higher line rate according to one of at least two methods (22, 24, 26). The filtered signal is sub-sampled (at 30, 32) at the source line standard where necessary, depending upon the degree of bandwidth reduction employed and one of the methods of pre-filtering and sub-sampling selected according (at 34) to a control signal (36) dependent on picture content. The luminance and chrominance components of the selected encoded signal are band pass filtered (46, 50, 52) and the chrominance signal modulated onto a sub-carrier (54) such that the frequency spectrum of the luminance and chrominance signals do not overlap.

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: A conventional video recorder comprises electromechanical components, electronic circuits and a control unit with which there are associated both front panel controls and a user remote control unit with a sensor to which signals can be sent from a hand-held remote control unit. In addition to these conventional features an off-air remote controller is provided. This is capable of decoding control signals associated with the television signal and includes an encoder which generates outputs which simulate those from the conventional user remote control unit.

Abstract: A video signal is coded for transmission in a restricted bandwidth by sub-dividing a frame of picture information into a set of constituent blocks, measuring the amount of picture activity in each block, sampling the information in each block at a rate related to the amount of picture activity in that block, and adding to the coded block a supplementary signal indicating the sampling rate used for the block. Thus a decision is made on a block-by-block basis as to whether the block is transmitted with full accuracy or whether it can be adequately reconstructed from the previous frames.

Abstract: In a color television signal the total line length or period and the bandwidth requirement can be conventional, but the active line period is increased to e.g. about 94% of the line period, giving an aspect ratio of about 3:2 instead of 4:3.