Abstract: A method and apparatus for preventing interference between simultaneously-running processes in a set top box processing system which attempt to access certain shared processing hardware such as a drawing acceleration engine. A graphics processor or other device such as a CPU associated with the processor includes a register with an acquire bit portion and a process identifier portion. When a given process requests access to a graphics engine or other shared processing hardware, a determination is made as to whether the acquire bit of the register is set. A set acquire bit indicates that some process has already been granted access to the engine. If the acquire bit is not set, the requesting process is granted access to the engine, and its process identifier is stored in the process identifier portion of the register.

Abstract: An apparatus and method for compressing multiple resolution versions of a video signal are disclosed. A first resolution version of a video signal is applied to an input of a first video compressor and to an input of a video scaler. The first video compressor encodes the first resolution version of the video signal to generate a first compressed video bit stream. The video scaler generates a reduced resolution version of the video signal from the first resolution version. The reduced resolution version is supplied to a second video compressor and to the first video compressor. The first video compressor utilizes the reduced resolution version of the video signal in performing a hierarchical motion estimation (ME) search as part of the encoding process for the first resolution version. The second video compressor encodes the reduced resolution version to generate a second compressed bit stream.

Abstract: A statistical multiplexing apparatus and method for generating and combining a plurality of encoded video bit streams. A storage device contains pre-stored a priori statistics indicative of the encoding complexity of the video signals from which the encoded video bit streams will be generated. The pre-stored a priori statistics may include inter-pixel differences in the same picture or between multiple pictures or pre-encoding a priori statistics generated during a preliminary encoding of the video signals. Examples of pre-encoding a priori statistics include the number of bits per picture at a given quantization level, an average quantization level, picture types, scene change locations and repeat field for one or more of the video bit streams. The video signals are applied to encoders which compress the signals in accordance with bit allocation decisions generated by a statistics computer.

Abstract: A method and apparatus for memory-efficient decoding of frame chroma of progressive frames. During the display of a first field of the frame, lines of interpolated chroma values are calculated for both even and odd field lines. The lines of interpolated values for the first field are generated by applying a two-tap filter with coefficients (1/4, 3/4) to corresponding lines of chroma samples, and the lines of interpolated values for the second field are generated by applying a two-tap filter with coefficients (3/4, 1/4) to the corresponding lines of chroma samples. The lines of first field interpolated values are displayed with the first field, while a given even line of second field interpolated values is written to memory locations occupied by a line of chroma samples used to generate the given line.

Abstract: A method and system are provided for capturing and compressing an original uncompressed video signal which enables decoding and reversible reconstruction of a decompressed version of the original video signal. The system includes an input for receiving a signal indicating a special effect operation by which a first frame of a video signal is irreversibly transformed to a special effect frame. This is achieved by combining decompressed frame pixel data of the first frame with information comprising either pixel data of a second frame or a single scaling value to be used to scale plural pixels of a frame. The information indicates a special effect operation which can be performed on decompressed pixel data of the first frame to produce a special effect frame (e.g., the information can include a separate indicator specifying a specific operation or the information by its mere presence can indicate the special effect operation). The system also includes a processor for compressing pixel data of the first frame.

Abstract: The present invention is directed to a method for encoding an uncompressed digital video bit stream. The video bit stream comprises successive frames, each of which includes one or more odd fields and one or more even fields. Such frames with more than two fields may result from a telecine process as discussed above. The inventive method comprises the steps of capturing successive frames of said video bit stream in an encoder system, determining statistics for each frame to make an encoding decision for the frame, the statistics for each frame being determined in a single field time, using a statistically valid subset of pixels from the frame, and encoding the frame in said encoding system in a manner responsive to said encoding decision to generate an encoded bit stream. In a preferred embodiment of the invention, the statistically valid subset of pixels has a checkerboard pattern.

Abstract: A shift register matrix including a matrix of cells having a plurality of rows and a plurality of columns, each cell storing one bit of data. A plurality of pulse generators is included to generate pulses to the cells which cause new data to be shifted into the cells. One pulse generator is included for each column of the matrix. The pulse generator for each column is coupled to all the cells in the column. Each pulse generator supplies a pulse to each of the cells in its respective column to cause new data to be shifted into the cells of that column. The pulses are sent to the respective columns in sequential order, one column at a time, until all the data in the matrix has been shifted by one bit.