Abstract: An integrated digital video system is configured to implement picture-in-picture merging of video signals from two or more video sources, as well as selective overlaying of on-screen display graphics onto the resultant merged signal. The picture-in-picture signal is produced for display by a television system otherwise lacking picture-in-picture capability. The digital video system can be implemented, for example, as an integrated decode system within a digital video set-top box or a digital video disc player. In one implementation, a decompressed digital video signal is downscaled and merged with an uncompressed video signal to produce the multi-screen display. The uncompressed video signal can comprise either analog or digital video. OSD graphics can be combined within the integrated system with the resultant multi-screen display or only with a received uncompressed analog video signal.

Abstract: A programmable bi-directional external graphics/video (EGV) port for a video decode system chip having a video decoder and an internal digital display generator circuit is provided. The programmable EGV port employs a fixed number of signal input/output (I/O) pins on the video decode system chip while providing a plurality of connection configurations for an external graphics controller, an external digital display generator circuit and an external digital multi-standard decoder to the video decoder or the internal digital display generator circuit of the chip. The EGV port includes receiver/driver circuitry for accommodating in parallel a plurality of input/output signals, including pixel data signals and corresponding synchronization signals, as well as a programmable port controller adapted to be coupled between the receiver/driver circuitry and an internal bus of the video decode system allowing access to at least one of the video decoder and the internal digital display generator circuit.

Abstract: Hardware logic and processing methods for enhanced data manipulation within a graphics display system are described. The graphics display system includes a graphics processor sub-system and a rendering subsystem which are serially connected for pipeline processing of an interleaved stream of commands and data. One or more status bits or XBITs are defined within each rasterizer of a multi-rasterizer rendering sub-system. An XBIT, which may comprise a ZBIT, a UBIT, or an RBIT, etc., provides a mechanism for introducing execution of various logic functions within the rendering sub-system portion of the computer graphics adapter. Corresponding data processing methods are also described.

Abstract: A method and apparatus for the management of the data associated with multiple graphics contexts in a computer graphics rendering system. Graphics contexts are built by graphics engines and selectively saved into a context save RAM. Context switches are managed either by modifying a context base pointer to address a new section of the context save RAM, or by writing out a portion of the context save RAM to external storage and reading in a replacement context from external storage. The writing and reading process are managed by a control processor allowing the graphics engines to switch context at the same time. New contexts read from external storage automatically cause regeneration of downstream rasterization parameters.