Abstract: A method of generating program clock reference values for a digital data stream is provided. The program clock reference value will preferably include a 33-bit base and a 9-bit extension. The method comprises the steps of receiving an input digital data stream having a pixel clock frequency, dividing the input frequency of the pixel clock and producing a counter clock that increments at a rate proportional to the pixel clock, multiplying the counter clock by a rational number to produce a number that indicates time expressed in 27 MHz periods and inputting the resulting value into a divider which divides every input by 300 to produce a quotient representing the Program Clock Reference value base and the remainder representing the Program Clock Reference value extension. A PCR generator for use in, for example, an MPEG encoder is also provided.

Abstract: A method and device for performing source transitions in a video system which performs entropy encoding such that a transition occurs only after the fields which define a frame picture have been received by the encoder. The method and device also provides arrangement for ensuring that initially after the switch to the second program source consecutive fields of information from the second program source which will be encoded as a frame picture are provided.

Abstract: A video projection system using a light modulating display device having a row and column matrix of picture elements is improved by imparting an oscillatory motion to the display image in the plane of the image, to thereby reduce the visibility of the individual picture elements of the matrix. The resolution of the image can be increased by displaying different video information at different parts of the oscillatory cycle.

Abstract: Data is embedded in a video signal by adding a low level wavefrom to the video signal, the low level wave form having a level below the noise level of the video signal and corresponding to the data. To detect the data embedded in the video signal the video signal is correlated with the low level waveform corresponding to the data to produce a correlation coefficient. A high correlation coefficient indicates the presence of a low level waveform which is converted into the data. The low level waveform extends over many video lines such that it does not occur at or near the same location within a video frame for many video frames to avoid fixed-pattern noise anomalies that may be detected by a viewer of the television picture.