Abstract: An improved video production architecture adds an additional transition element for controlling external devices in synchronism with a given transition so that the transition is treated like a simple mix or wipe. The additional transition element is a “Trigger” function that has a value indicating when during the given transition the external device is activated. The trigger function, device controlled and trigger value are set up during preconfiguration of an effect in an effects memory. When the effect is recalled, if the Trigger function is activated on a switcher control panel, then the external device is activated at the time during the given transition specified by the trigger value.

Abstract: A mix/effect status display provides simultaneous information about each keyer and bus associated with a mix/effect bank without consuming the real estate required for the conventional button/knob per function approach. Also the sources coupled to the M/E buses are shown together with the transition status if a transition is in progress. A switcher working buffer has information about the switcher control panel controls, and transfers that information that relates to the mix/effects banks to a mix/effects status display driver. The driver provided the mix/effects status display with a row for each bus associated with the M/E and all information related to the source coupled to that bus together with information about the M/E operating mode and transition status, type and interval. Thus an operator has a complete picture of M/E status without requiring substantial additional real estate on the switcher control panel.

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: 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 method of recalling effects between mix/effects banks of a video production switcher uses a Recall From function button on a destination mix/effects bank to copy a desired effect stored in an effects memory on another M/E bank into a working effects register of the destination mix/effects bank when the Recall function for the other M/E bank is then used. The effect from the storing M/E bank is copied into a working effects register on the destination M/E for execution while the working effects register on the storing M/E bank is not affected so that the effect stored in the working effects register of the destination M/E is not destroyed.

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: 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 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 recording time code in a database is disclosed which makes it easy to search for video segments on a target medium while making the original source time code available on playback. As a video segment from a source medium is recorded on the target medium the time code from the first frame of the video segment is extracted and held. The number of frames of the video segment are counted to determine a duration, and at the conclusion of the video segment the extracted time code together with the duration and a location code indicating where on the target medium the video segment is stored are formed into a data structure that is stored in a break table in the database as a "break" entry. The break table is sorted, optimized to eliminate any break entry overlaps, and updated after each new break entry.

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 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 method for synchronization of a digital audio signal sampled at a standard audio frequency with the corresponding digital video signal sampled at a standard video frequency associates an integer number of samples of the digital audio signal with each video field of the digital video signal. The number of audio samples per video field is determined by the audio sample rate rounded up to the nearest integer. Every N video fields where the number of digital audio samples is an integer value, the digital audio signal is resynchronized with the digital video signal by repeating the digital audio samples at the end of video field N that correspond to video field N+1. At reception the same digital audio samples are skipped at the end of video field N.

Abstract: A simple compositing system for combining sequences of images, including graphics and video images, records the sequences onto a disk recorder. A frame from each sequence in turn is processed by a digital picture manipulator channel and stored in a respective frame store. Once one frame from each sequence is processed and stored, the frames from the frame stores are combined in a video combiner to form a composite frame, which is read back into the disk recorder. All of the frames of the sequences are combined in this manner to form composite frames, the totality of composite frames producing a final composite image sequence stored in the disk recorder. The final composite image sequence is then transferred to an output device in real time.

Abstract: Video signal processing apparatus comprises at least first and second source selectors each having a plurality of input terminals, for receiving a plurality of video signals respectively, and at least two output terminals. A set of video processors each have an input terminal and an output terminal. A processor selector is provided for connecting each source selector output terminal selectively to each video processor input terminal. First and second output devices each have a plurality of input terminals connected to the output terminals of the video processors respectively and also have an output terminal. Operator interfaces are connected to the processor selector for defining a first subset of video processors having their input terminals connected to the output terminals of the first source selector and a second subset of video processors having their input terminals connected to the output terminals of the second source selector.

Abstract: A video switcher comprises a source selector having a plurality of input terminals for connection to a plurality of video sources respectively, and at least two output terminals. At least two processing channels each have an input terminal connected to an output terminal of the source selector and also have an output terminal. A video combiner has video input terminals connected to the output terminals of the processing channels and is operative to combine the output signals provided by the processing channels in dependence upon priority signals.

Abstract: A first shaped video signal V.sub.1 K.sub.1 and a second shaped video signal V.sub.2 V.sub.2, are combined so as to generate a third shaped video signal V.sub.3 ' given byV.sub.3 '=V.sub.1 K.sub.1 [1-K.sub.2 (1-P.sub.12)]+V.sub.2 K.sub.2 (1-K.sub.1 P.sub.12)where P.sub.12 is a priority signal. A key signal K.sub.3 given byK.sub.3 =1-(1-K.sub.1)(1-K.sub.2)is also generated. An output processor receives the shaped video signal V.sub.3 ', the key signal K.sub.3 and a matte signal M.sub.3. In a first mode of operation, the output video signal V.sub.3 " of the output processor is given byV.sub.3 "=V.sub.3 +M.sub.3 (1-K.sub.3)and the key signal K.sub.3 ' that is generated by the output processor has a constant value, and in a second mode of operation of the output processor the output video signal is given byV.sub.3 "=V.sub.3 '/K.sub.3and the key signal K.sub.3 ' is directly proportional to K.sub.3.