Abstract: A bidirectional serial port for digital audio data includes a cable connector for coupling the port to a cable, a cable driver having a serial digital audio signal as an input and also having an output, a receiver having an input and an output, and an impedance and level matching network coupled to the output of the cable driver, the input of the receiver, and the cable connector. The port can be selectively configured either as an input port by causing the impedance and level matching network to act as a cable termination or as an output port by allowing the serial digital audio signal to pass through the cable driver and the impedance and level matching network to the cable connector.

Abstract: A graphical source ID display has a plurality of display regions aligned with respective columns of source selector buttons. Each display region has a bit-map representation, either iconic or textual, that identifies the source associated with that column. The display regions may further be backlit. The bit-map representation is entered into a display controller by an operator during setup, the display controller providing the bit-map representations to the appropriate display regions.

Abstract: A digital video recorder employing standard hard disk arrays employs a caching system to enable continuous video data to be supplied to and provided from the standard disk drives which may not be adapted for continuous data stream operation. The system is implemented as an array of disk drives and includes cache management functions for governing disk read and write operations. A predictor enables the cache to predict disk reads and disk writes and to maintain the cache based on the predictions. Redundancy enables playback in the event of failure of a drive in the array and also provides improved playback data retrieval time.

Abstract: A histogram-based segmentation of an image, frame or picture of a video signal into objects via color moments is initiated by defining a relatively large area within the object. The defined area is characterized by its color information in the form of a limited set of color moments representing a color histogram for the area. Based upon the set of color moments, color moments generated for small candidate blocks within the image, an automatically generated weighting vector, distance measures for the blocks from a central block in the object and a tolerance the area is grown to encompass the object to the extent of its boundaries. The initial set of color moments are then updated for the entire object. Those candidate blocks within the object serve to segment the object from the image.

Abstract: Linking keyers to background source selections is achieved by defining a key link association table between background sources and keyers for an M/E of a production switcher. Key Add and Key Drop modifiers are provided so that the effects of the key link association table may be modified while making a background source change.

Abstract: A mix/effect bank has its capability doubled by increasing the number of keyers input from two to four. The outputs from the keyers are routed through a crosspoint matrix for form a current and a next stack representing the priority of the keyer outputs from highest to lowest. The current stack is input to a current priority combiner and the next stack is input to a next priority combiner. The output of the current priority combiner is a program video output bus and the output of the next priority combiner is a preview video output bus. The two buses are input to a transition mixer, the output of which is coupled through a program/preview switch to the program video output bus. The transition mixer passes the output of the current priority combiner to the program video output bus except when the transition is made between preview and program, at which point the transition product is provided to the program video output bus.

Abstract: A digital video recorder employing standard hard disk arrays employs a caching system to enable continuous video data to be supplied to and provided from the standard disk drives which may not be adapted for continuous data stream operation. The system is implemented as an array of disk drives and includes cache management functions for governing disk read and write operations. A predictor enables the cache to predict disk reads and disk writes and to maintain the cache based on the predictions. Redundancy enables playback in the event of failure of a drive in the array and also provides improved playback data retrieval time.

Abstract: A mix-effect bank architecture for a production video switcher has multiple programmable outputs, the outputs being determined by a selected operational mode including split, programmable clean feed and mix minus modes. Four keyers with video and key signal inputs produce four outputs. The outputs are selectively routed to four corresponding inputs of four mixers, which mixers also have two pairs of background/utility video inputs. The four mixers provide four outputs which are determined by the selected operating mode. A pair of background video signals may be provided to all of the mixers to provide programmable clean feed outputs, or the pair of background video signals and a mix minus pair of background video signals may be provided to the mixers to provide mix minus outputs, or a primary set of background video signals may be provided to two mixers and a secondary set of background video signals may be provided to the other two mixers for the split mode.

Abstract: A method of concealing temporal shifts when a digital video effects system is used with a video switcher adds a mixer to the digital video effects system to mix the input to and output from the digital video effects system if the image to be transformed is on-screen at the beginning of the effect. An input video signal from a keyer in the video switcher is switched by an effects send/return matrix to the inputs of the digital video effects system and the mixer, and the output from the mixer is returned to the effects send/return matrix for input to the mix/effects stage of the video switcher. When the digital video effects system is bypassed, a delay circuit is used in the bypass path of the effects send/return matrix, the delay time equaling the processing time of the mixer.

Abstract: A bi-directional serial video port coupled to a cable has a cable driver coupled to a cable connector via a D.C. blocking capacitor and a cable impedance matching resistor in series. A receiver is coupled to the cable connector via a decoupling capacitor. When configured as an input port, a control signal causes the output from the cable driver to be low so that the cable impedance matching resistor forms a termination for a cable connected to the cable connector and the receiver passes at serial digital video signal from the cable connector for further processing. Otherwise a serial digital video signal is passed by the cable driver to the cable and the output from the receiver is disregarded.

Abstract: A low jitter method for extracting clock or data from a serial digital bitstream generates from a digital decoder a window signal from the serial digital bitstream by sampling the serial digital bitstream with a sample clock signal. The window signal envelops a specified transition of the serial digital bitstream, and is used as a gate input to an AND circuit to extract the clock signal or desired data from the bitstream without introducing jitter. The clock signal may then be used to clock out data previously extracted by the digital decoder.

Abstract: A method of modifying a group of pictures (GOP) structure in an MPEG video signal from a low-delay mode bitstream having I and P pictures to a non-low-delay bitstream having I, P and B pictures uses the motion vectors from the low-delay mode bitstream to derive the motion vectors for the non-low-delay mode bitstream. Motion vectors for anchor pictures for the non-low-delay mode bitstream are converted from the motion vectors for the corresponding pictures in the low-delay mode bitstream. Motion vectors for the B pictures in the non-low-delay mode bitstream are converted from the motion vectors for the corresponding P pictures in the low-delay mode bitstream. The converted motion vectors for the non-low-delay mode bitstream are used in recoding an uncompressed video signal derived from the low-delay mode bitstream to produce the non-low-delay mode bitstream.