Evertz Microsystems Ltd.

Leitch Technology International Inc.

Leitch Technology Corporation

Semko Szybiak

Romolo Magarelli

Keping Chen

Alan Plaunt

A system and method for time division multiplexing multiple lower bandwidth signals into a high bandwidth signals such as a high-definition television signal. The invention provides an integrated transmission, distribution and routing signal format in which low-bandwidth signals are embedded in the active video and vertical blanking areas of a high-bandwidth signal. Data from the source data streams, including timing data, is formatted in packets, each packet comprising a plurality of channels. The packets are inserted into the high-bandwidth signal along with a header word providing a 'data valid bit' or 'status bit' for each of the channels, which identifies valid data words within the packet. The source data streams are accurately reconstituted by de-multiplexing according to header data specifying routing destination, stream ID, stream type, channel usage and stream clock reference for clock recovery at the receiving end.

System and method for time division multiplexing of asynchronous video and data signals

A circuit for detecting a transition in the content of a digital video stream containing embedded audio samples and providing a smooth transition from an old audio stream embedded before the transition to a new audio stream embedded after the transition. The circuit detects the transistion and in response it fades out the old audio stream and fades in the new audio stream. During the transition, the old and new audio signal are buffered. The old stream is not faded out until only a number of audio samples required for the fading process remain in the associated buffer. The new audio stream is not faded in until a selected number of audio samples have been stored I the associated buffer. The selected number of samples is typically smaller than the number of samples that is desirably stored in the associated buffer during steady state operation. An interpolation operation is used to allow the number of new audio samples in the associated buffer to build up to the desired number.

Circuit and method for live switching of digital video programs containing embedded audio data

A system for detecting picture freeze within a video signal wherein a video signal processing portion for connection to a video signal source comprising digital video luma samples and digital video clock and timing signals separately detects motion across the vertical axis of the video picture and across the horizontal axis of the video picture and wherein a frozen picture indicating portion connected to the output of the video signal processing portion determines the number of motionless video picture frames occurring since the last video picture frame in which motion was detected to indicate picture freeze when the number of motionless video picture frames reaches a predetermined value. A noise reduction threshold signal is applied to the video signal processing portion to distinguish motion from background noise in a video signal.

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Scarborough, Canada

Semko Szybiak