Abstract: A video and graphics system has a reduced memory mode in which video images are reduced in half in horizontal direction during decoding. The video and graphics system includes a video decoder for decoding MPEG-2 video data. The video images may not be downscaled in the horizontal direction when no bi-directionally predicted pictures are used. The video and graphics system may output an HDTV video while converting the HDTV video and providing as another output having an SDTV format or another HDTV format. The output having an SDTV format may be recorded using a video cassette recorder (VCR) while the HDTV video is being displayed.

Abstract: A graphics display system integrated circuit processes analog video input, digital video input, and graphics input. The system incorporates a graphics accelerator that includes memory for graphics data. The accelerator preferably includes a coprocessor for performing vector type operations on a plurality of components of one pixel of the graphics data. The accelerator also includes an expanded instruction set for storing and loading data.

Abstract: A graphics integrated circuit chip is used in a set-top box for controlling a television display. The graphics chip processes analog video input, digital video input, and graphics input. The chip blends graphics and video information by various graphics windows using alpha values for the windows, alpha values per pixel, or both. The chip calculates a composite alpha value based on the window's alpha values and the alpha values per pixel. Blended graphics and video may then be composited using the composite alpha value.

Abstract: A graphics integrated circuit chip is used in a set-top box for controlling a television display. The graphics chip processes analog video input, digital video input, graphics input and audio input simultaneously. The system includes a video decoder having a chroma-locked sample rate converter. The chroma-locked sample rate converter converts the samples to those taken at a sample rate that is a multiple of the chroma subcarrier frequency and that is locked to chroma bursts of the analog video signal in a control loop. The video decoder also includes a line-locked sample rate converter that receives samples at a multiple of the chroma subcarrier frequency and converts the samples to samples with a sample frequency that is a multiple of the horizontal line rate of the video input. The line-locked sample rate converter measures the horizontal line rate to an accuracy of a fraction of a pixel and adjusts the sample rate and phase of the line-locked sample rate converter to produce accurate line-locked samples.

Abstract: A graphics integrated circuit chip is used in a set-top box for controlling a television display. The graphics chip processes analog video input, digital video input, and graphics input. The chip includes a single polyphase filter that preferably provides both anti-flutter filtering and scaling of graphics. Anti-flutter filtering may help reduce display flicker due to the interlaced nature of television displays. The scaling of graphics may be used to convert the normally square pixel aspect ratio of graphics to the normally rectangular pixel aspect ratio of video.

Abstract: A graphics integrated circuit chip is used in a set-top box for controlling a television display. The graphics chip processes analog video input, digital video input, a graphics input and an audio input simultaneously. The chip uses window descriptors to describe logical surfaces, or windows, of graphics information to be displayed on the screen. The chip incorporates a unified memory architecture that provides a high level of system performance while conserving memory bandwidth and chip size. Video and graphics scaling capabilities as well as anti-flutter filtering capability are provided.

Abstract: A graphics display system integrated circuit is used in a set-top box for controlling a television display. The graphics display system processes analog video input, digital video input, and graphics input. The system incorporates a unified memory architecture that is shared by the graphics system, a CPU, and other peripherals. The unified memory architecture uses real time scheduling to service tasks. Critical instant analysis is used to find a schedule for memory usage that does not affect memory requirements of real time tasks while at the same time servicing non-real-time tasks as needed.

Abstract: A graphics integrated circuit chip is used in a set-top box for controlling a television display. The graphics chip processes analog video input, digital video input, graphics input and audio input simultaneously. A video scaling system preferably conserves memory by downscaling video prior to capturing the video in memory and upscaling video after the video is called out of memory.

Abstract: Systems and methods that control prefetching are provided. In one embodiment, a system may include, for example, a prefetch buffer system coupled to a processing unit and to a memory. The prefetch buffer system may include, for example, a prefetch controller that is adapted to be programmable such that prefetch control features can be selected.

Abstract: A graphics integrated circuit chip is used in a set-top box for controlling a television display. The graphics chip processes analog video input, digital video input, and graphics input. The chip blends graphics and video information by various graphics windows using alpha values for the windows, alpha values per pixel, or both. The chip calculates a composite alpha value based on the window's alpha values and the alpha values per pixel. Blended graphics and video may then be composited using the composite alpha value.

Abstract: A graphics integrated circuit chip is used in a set-top box for controlling a television display. The graphics chip processes analog video input, digital video input, a graphics input and an audio input simultaneously. The chip processes graphics images organized as windows. The chip obtains data that describes the windows, sorts the data according to the depth of the window on the display, transfers graphics images from memory, and blends the graphics images using alpha values associated with the graphics images.

Abstract: A graphics integrated circuit chip is used in a set-top box for controlling a television display. The graphics chip processes analog video input, digital video input, graphics input and audio input simultaneously. A video scaling system preferably conserves memory by downscaling video prior to capturing the video in memory and upscaling video after the video is called out of memory.

Abstract: A graphics integrated circuit chip is used in a set-top box for controlling a television display. The graphics chip processes analog video input, digital video input, a graphics input and an audio input simultaneously. The chip includes a display engine that processes graphics images organized as windows. The system includes plurality of line buffers for receiving the graphics contents. The graphics contents are composited into each of the plurality of line buffers by blending the graphics contents with the existing contents of the line buffer until all of the graphics surfaces for the line have been composited.

Abstract: A display engine of a video and graphics system includes one or more processing elements and receives graphics from a memory. The graphics data define multiple graphics layers, and the processing elements process two or more graphics layers in parallel to generate blended graphics. Alpha values may be used while blending graphics. The processing elements may be integrated on an integrated circuit chip with an input for receiving the graphics data and other video and graphics components. The display engine may also include a graphics controller for receiving two or more graphics layers in parallel, for arranging the graphics layers in an order suitable for parallel processing, and for providing the arranged graphics layers to the processing elements. The blended graphics may be blended with HDTV video or SDTV video, which may be extracted from compressed data streams such as an MPEG Transport stream.

Abstract: A graphics integrated circuit chip is used in a set-top box for controlling a television display. The graphics chip processes analog video input, digital video input, a graphics input and an audio input simultaneously. The chip processes graphics images organized as windows. The chip obtains data that describes the windows, sorts the data according to the depth of the window on the display, transfers graphics images from memory, and blends the graphics images using alpha values associated with the graphics images.

Abstract: Aspects of the invention may include a method updating a color look-up table (CLUT) for a next line of graphics before a current line of graphics has been completely read out of a graphics FIFO and assigned color pixel values. The method may include the step of formatting or arranging the CLUT into a plurality of sub-CLUTs. Each one of the sub-CLUTs may include pixel color values for each one of a plurality of pixels which may include a line of the graphics image data. Pixel color values may be read from within a first selected sub-CLUT, the first selected sub-CLUT comprising pixel color values for a first line of the graphics image data. The read pixel color value may be applied to the current first line of the graphics image data. While the read pixel color value is being applied to the current first line, pixel color values for a second selected sub-CLUT may be updated. The second selected sub-CLUT may include color pixel values for a second line of the graphics image data.

Abstract: Aspects of the invention may include gradually decrementing or incrementing a write pointer (370) associated with a data buffer such as the FIFO buffer (310) until a reset value of the write pointer (370) is reached in response to an indication that a data buffer controlled by the gray code counter is empty. Additionally, a read pointer (380) associated with the data buffer (310) may be gradually incremented or decremented until a reset value of the read pointer (380) is reached in response to an indication that the data buffer controlled by the gray code counter is full. The data buffer may be a first-in-first-out (FIFO) buffer such as FIFO buffer 310, which may be asynchronously clocked. The data buffer may be adapted to buffer any one or a combination of video, voice and data.

Abstract: A graphics display system integrated circuit is used in a set-top box for controlling a television display. The graphics display system processes analog video input, digital video input, and graphics input. The system incorporates a unified memory architecture that is shared by the graphics system, a CPU, and other peripherals. The unified memory architecture uses real time scheduling to service tasks. Critical instant analysis is used to find a schedule for memory usage that does not affect memory requirements of real time tasks while at the same time servicing non-real-time tasks as needed.

Abstract: A graphics integrated circuit chip is used in a set-top box for controlling a television display. The graphics chip processes analog video input, digital video input, a graphics input and an audio input simultaneously. The chip includes a display engine that processes graphics images organized as windows. The system includes plurality of line buffers for receiving the graphics contents. The graphics contents are composited into each of the plurality of line buffers by blending the graphics contents with the existing contents of the line buffer until all of the graphics surfaces for the line have been composited.

Abstract: A graphics display system integrated circuit processes analog video input, digital video input, and graphics input. The system incorporates a graphics accelerator that includes memory for graphics data. The accelerator preferably includes a coprocessor for performing vector type operations on a plurality of components of one pixel of the graphics data. The accelerator also includes an expanded instruction set for storing and loading data.