Abstract: Methods and apparatuses to detect presence of undesirable video abnormalities during, for example, video ingest or playback. These undesirable characteristics may include an average picture level that is less than a preset threshold value, or static input, in which the content does not change over a significant number of frames. Detection of abnormalities results in an alarm to a system operator. Analysis and alarm may occur automatically during processing of video data streams. The same abnormalities may be detected during playback of the image data.

Abstract: An application programming interface for a digital disk recorder uses a port to link resources together to form a multimedia recorder that emulates a tape recorder while retaining the flexibility of the digital disk recorder. The port is a matrix of timelines for each resource, with each track in the port representing a media stream associated with a different one of the resources. A dynamic subsystem controls recording and playing back multimedia between the resources and a disk file system of the digital disk recorder using the port. A static subsystem maintains on the disk file system a database of movies recorded by the digital disk recorder from the resources according to the port, with each movie being a collection of media files for each resource that are independently accessible.

Abstract: A system for automatic generation of vector reference graticules for a vectorscope display acquires the active video portion of a video signal that includes a color bar test signal. The values for each color difference component at each reference color plateau for the acquired color bar test signal are averaged to provide horizontal and vertical displacement values for each reference color, including black. Graticule boxes are electronically generated and positioned for each reference color on a display according to the respective horizontal and vertical displacement values.

Abstract: A test signal generator applies a test pattern to a device under test. The output of the device under test is displayed on a video picture monitor. The test signal generator inserts a cursor into the test pattern, the position of the cursor within the test pattern being variable. From the cursor the test signal generator also generates a trigger signal. The trigger signal may be used to trigger the horizontal sweep of a waveform display device to which the output of the device under device is input. By observing the picture monitor an operator may adjust the cursor to a position just prior to an anomaly in the displayed test pattern so that only that portion of the output waveform of the device under test in the vicinity of the cursor is displayed on the waveform display device.

Abstract: A three-dimensional test signal for a video codec is generated by injecting a conventional foreground test signal at a predetermined location as a foreground component within a background test signal as a background component, the background component having a variable complexity. The three-dimensional test signal is input to the video codec and the output of the video codec is measured using conventional measurement instruments. The background component may be a pseudo-random noise signal, a zone plate signal or other variable complexity-type signal, with the foreground component occurring at greater intervals than the neighboring pixels used by the codec compression algorithm. The conventional measurement instruments display only the foreground component with distortions in the video codec caused by the complexity of the background component appearing in the display.

Abstract: Spatial bandwidth testing for digital data-compressed video systems is performed using a complex, or high entropy, test signal. A portion of the test signal is acquired as a control frame. This control frame is divided into a plurality of blocks. Each block is processed by a two-dimensional Discrete Fourier Transform (DFT). The test signal is input to a digital data-compressed video system and a corresponding portion of the output of the video system, a test frame, is acquired and processed in the same manner as the control frame. The resulting coefficient arrays from the control and test frames are compared to each other to obtain an output array of ratios for each block. The ratio of those coefficients corresponding to the predominant frequency of each block of the control frame are displayed as a three-dimensional gain plot. The ratio of those coefficients corresponding to low frequencies of each block of the control frame are displayed as a three-dimensional noise plot.

Abstract: A method of compressing a digitized waveform into a sequence of N-bit words includes selecting corresponding bit values from N data words and generating a value based thereon. A next N input words are selected and the corresponding bits are used to generate a next value. The process is continued for each significant bit of the input sequence and the generated value stream is run-length encoded to produce a compressed data output stream.

Abstract: A delay time between the start of a trace on an oscilloscope screen and a point along the trace is computed based on measured "sweep gain" and "sweep start" parameters characterizing a triggered sweep signal controlling the horizontal position of an electron beam creating the trace, the sweep signal increasing when triggered from a starting level at a constant slew rate to move the beam at a constant speed across the screen. The sweep start parameter is the value of input data applied to a digital-to-analog converter (DAC) which would cause the DAC to produce an output voltage equal to the sweep signal starting level, and the sweep gain indicates the rate of increase in DAC input data required to produce a DAC output signal with a rate of increase similar to the slew rate of the sweep signal. The horizontal position of the point along the trace is the beam position on the screen at the moment the sweep signal magnitude reaches the magnitude of the DAC output signal.

Abstract: An instrument for providing a principal display representing the variation of a first quantity as a function of a second quantity, comprises a display screen. A visually distinct dot is generated on the display screen and is deflected along one of two orthogonal axes in dependence upon the value of the first quantity and along the other axis in dependence upon the value of the second quantity. The dot is additionally deflected to selected positions along the two axes to generate an auxiliary display of a marker and of an information-conveying character adjacent the marker. The position of the auxiliary display is adjustable along at least one of the axes.

Abstract: In an oscilloscope, a readout control circuit is adapted to create a horizontal cursor on an oscilloscope screen at a vertical level controlled by cursor level data generated by a microcomputer, and to cause the beam to form characters on the screen indicating a voltage represented by the vertical level of the cursor. Vertical offset and vertical gain parameters characterizing a vertical preamplifier system controlling display of a waveform are measured and utilized to determine the value of cursor level data needed to cause the readout control circuit to position the cursor on the screen to accurately reflect a selected voltage with respect to voltage magnitudes represented by points on the displayed waveform.