Abstract: A flicker filter is adjusted according to degree of alpha blending performed on a display signal. For some weakly showing graphics images, a lower flicker filter level may be implemented or the flicker filter may be turned off. A threshold for turning off the flicker filter may be programmable. Other embodiments are described and claimed.

Abstract: A flicker filter is adjusted according to degree of alpha blending performed on a display signal. For some weakly showing graphics images, a lower flicker filter level may be implemented or the flicker filter may be turned off. A threshold for turning off the flicker filter may be programmable. Other embodiments are described and claimed.

Abstract: A flicker filter is adjusted according to degree of alpha blending performed on a display signal. For some weakly showing graphics images, a lower flicker filter level may be implemented or the flicker filter may be turned off. A threshold for turning off the flicker filter may be programmable. Other embodiments are described and claimed.

Abstract: A pixel clock frequency is adjusted in response to periodically monitoring the relative positions between a video signal to be displayed and a video signal captured. Image shear of the display signal may be avoided quickly. Adjustments are made to the color burst signal where dramatic changes in the pixel clock frequency result.

Abstract: A digitally encrypted audio signal may be transmitted with an analog television signal. Access to the analog television video signal may be controlled by using graphics overlay techniques. The use of digital encryption techniques on the audio channel prevents improper interception.

Abstract: A flicker filter is adjusted according to degree of alpha blending performed on a display signal. For some weakly showing graphics images, a lower flicker filter level may be implemented or the flicker filter may be turned off. A threshold for turning off the flicker filter may be programmable.

Abstract: A pixel clock frequency is adjusted in response to periodically monitoring the relative positions between a video signal to be displayed and a video signal captured. Image shear of the display signal may be avoided quickly. Adjustments are made to the color burst signal where dramatic changes in the pixel clock frequency result.

Abstract: Prior art methods of decoding a vertical blanking interval (VBI) scan line decoded each scan line within a given VBI using the same operational parameters, such as filter coefficients and run-in clock recovery parameters. The problem with these prior art methods is that each scan line was treated the same, even though certain scan lines within a given VBI typically exhibit different signal and content characteristics. The present invention provides for line-specific decoding of VBI scan lines. As such, each scan line within a given VBI is decoded using a set of operational parameters unique to that scan line number. These operational parameters are adjusted and maintained on a scan line by scan line basis.

Abstract: A mechanism for adaptive selection of anti-ghosting filtering accesses a first plurality of coefficients being used by the anti-ghosting filtering and compares a first set of one or more of the first plurality of coefficients to a first predetermined value. The mechanism then modifies the anti-ghosting filtering based on the results of this comparison. In one embodiment, the mechanism includes both an adaptive baseband equalization filter and a lookup table filter.

Abstract: A method and apparatus are provided for performing host-based anti-ghosting of teletext data in a television signal using non-oversampled data. Teletext data is first encoded within a television signal using multi-level error correction encoding, including the use of an inner correction code and an outer correction code. The television signal is then transmitted using multiple signal level modulation encoding, while adhering to the standard teletext timing. A remote computer system receives the television signal containing the encoded teletext data. A tuner/capture subsystem of the computer system oversamples the teletext data and uses the oversampled data to reconstruct the bit peaks of the teletext data. The teletext data are then provided to a main memory of the computer system via a host interface as non-oversampled data. The host processor performs anti-ghosting, data slicing, and multi-level decoding of the teletext data based on the non-oversampled data.

Abstract: A method and apparatus for supporting variable sampling rates when decoding vertical blanking interval data receives an indication of a sampling rate being used to sample a signal received during the vertical blanking interval. The sampled signal is also received and the data embedded in the vertical blanking interval is recovered based on the sampling rate.

Abstract: Binding data sinks and sources across ring levels of a computer. A new binding channel is created and attached to a comm channel. A unique name is created for the binding channel, and a handle to the unique name is obtained at a relatively low priority ring level. The handle is passed to an unbound relatively high priority ring level code module.

Abstract: A method and apparatus for raster calibration is described. Calibration circuitry operates in the context of a local video subsystem which receives at least one sync signal from a remote video (typically graphics) subsystem. The calibration circuitry calibrates a local raster of the local video subsystem to a remote raster of the remote video subsystem. The calibration circuitry includes measurement circuitry for measuring a first duration of a first phase of the sync signal, and for measuring a second duration of a second phase of the sync signal. Processing logic compares the first and second durations and determines that the phase having the shorter duration is an active phase, the active phase corresponding to the polarity of the sync signal. The processing logic also adds the first and second durations to provide an estimate of the scan line period of the remote raster.

Abstract: A hardware system is programmed with a common vertical blanking interval (VBI) scan line decoder to support capture hardware of multiple vendors. The common decoder includes a first and a second function for a capture driver associated with a capture hardware to describe to the common decoder, the sample rate and the line pitch employed by the capture hardware respectively. The common decoder further includes additional functions for the capture driver to confirm the common decoder's presence, register a call back function, specify a channel, and request decoding for a field.

Abstract: Transmitting data chunks in a computer system having different computing ring levels. A data chunk is accepted by a relatively low priority ring module from a relatively high priority ring source. The address of the data chunk is translated into the address space of the low priority ring module. The low priority ring module is notified of the availability of the data chunk.

Abstract: A hardware system is programmed with a noise tolerant vertical blanking interval (VBI) scan line run-in clock recovery function that determines the phase adjustment for reading sampling data, using only phase error observations that fall within a heavily populated phase error super-subrange, and excluding the remaining phase error observations from the determination, thereby improving the precision of the determination, and reducing unnecessary rejections of VBI scan lines.

Abstract: Methods and apparatuses for generating an image for display without creating a scaled bitmap. One or more bytes of digital data corresponding to portions of the image are received, scaled horizontally and vertically for display, and transmitted for display. In a preferred embodiment, encoded data corresponding to the image are decoded before being scaled for display. In an alternative preferred embodiment, analog signals corresponding to the image are generated, decoded, digitized, captured, compressed, and decompressed. The data displayed may be either the captured data or the decompressed data.

Abstract: A hardware system is programmed with a vertical blanking interval (VBI) scan line run-in clock recovery function, preferably noise tolerant that optimizes the starting point for recovering the leading run-in clock of a VBI scan line by maintaining at least one average starting position for VBI scan lines, and using the at least one average starting position to establish the starting point. The at least one average starting position is updated continuously with the actual locations where first rising edges in the run-in clocks of various scan lines are found.

Abstract: Methods and apparatuses for generating an image for display without creating a scaled bitmap. One or more bytes of digital data corresponding to portions of the image are received, scaled horizontally and vertically for display, and transmitted for display. In a preferred embodiment, encoded data corresponding to the image are decoded before being scaled for display. In an alternative preferred embodiment, analog signals corresponding to the image are generated, decoded, digitized, captured, compressed, and decompressed. The data displayed may be either the captured data or the decompressed data.

Abstract: A method and apparatus for the self-correcting of anti-ghosting filter coefficients is provided. A plurality of coefficients associated with an anti-ghosting filter are monitored as data is received by the filter. The plurality of coefficients are adjusted if one or more of the plurality of coefficients exceed a first value. In one embodiment, the filter is an adaptive baseband equalization filter. If the magnitude of one or more secondary coefficients of the adaptive baseband equalization filter exceed a predetermined factor of the primary coefficient, then the plurality of coefficients are adjusted. In another embodiment, the filter is a lookup table filter. If the magnitude of a coefficient in the lookup table is greater than a predetermined value, the plurality of coefficients are adjusted.