Abstract: A method and apparatus for concealing errors during decoding of a video bit stream utilize estimates, if possible, motion vectors in the temporal domain. If estimation in the temporal domain is not possible, motion vectors are estimated in the spatial domain. A macroblock is then estimated based upon the estimated motion vector. If estimation in the spatial domain is not possible, macroblock estimation is made without the use of an estimated motion vector.

Abstract: A circuit arrangement and method utilize a distributed extensible processing architecture to allocate various DSP functions or operations between multiple processing cores disposed on an integrated circuit device. Each processing core includes one or more hardwired datapaths to provide one or more DSP operations. Moreover, each processing core includes a programmable controller that controls the operation of each hardwired datapath via a local computer program executed by the controller. Furthermore, the processing cores are coupled to one another over a communications bus to permit data to be passed between the cores and thereby permit multiple DSP operations to be performed on data supplied to the device.

Abstract: A special purpose reduced instruction set central processing unit (RISC CPU) for controlling digital audio/video decoding. The instruction set includes flow control instructions which incorporate immediate values, used to jump over a small number of instructions, and other instructions used for larger jumps. Also, instructions obtain data from the video decoder of the ASIC in a streamlined fashion, using video decoder addresses hard-coded into the RISC CPU. Further instructions perform manipulations of individual bits of registers used as state/status flags. The RISC CPU includes watchdog functions for monitoring the delivery of data to the RISC CPU from other functional units or from memory, so that the RISC CPU can execute instructions while delivery of data from memory or other functional units is pending, unless that data is necessary for program execution, in which case, program execution stalls until the data arrives.

Abstract: An improved architecture for a digital video processor that processes subvideo data to be superimposed on a main video image during a display image scanning process. The improved digital video processor divides and partitions the execution of subvideo data between a programable CPU and a dedicated hardware processor. The CPU is used to process the simpler, less time critical, nonpixel data, and the more complex, more time critical pixel data is processed in real time using a dedicated hardware processor operating under the control of the CPU. The improved digital video processor is adaptable to process subvideo data being supplied in different data formats.

Abstract: A reduced instruction set CPU is programmed to provide software-controlled task management, a stack, and to manage virtual instruction memory. The CPU performs a task management procedure in which the CPU repeatedly checks task flags, and if a task flag is set, performs the task associated with the set task flag. If multiple task flags are set, the highest priority task of those associated with set task flags is performed. Whenever a subroutine call is needed, the subroutine call is implemented by calling a stack management routine. The stack management routine retrieves and stores a return address into a location in DRAM identified by a stack pointer, increments the stack pointer, and then executes a CALL instruction, causing program execution to sequence to the desired subroutine.

Abstract: A decoding circuit for decoding (or decompressing) compressed video data includes an RL circuit, such as MPEG encoded video data. The RL circuit includes a buffer memory for storing run-level pairs during the decoding process. Because the buffer memory in the RL circuit can store ran-level pairs, Huffman-decoding and header decoding, performed by a variable length decoding (VLD) circuit, is decoupled from inverse discrete transform decoding, performed by an IDCT circuit. This decoupling speeds up the decoding pipeline by allowing more continuous operation by both the VLD and IDCT circuits.

Abstract: The present invention provides a method (200) and an apparatus (100) for spatially adaptive filtering for video encoding. The apparatus filters a video sequence prior the encoding process. The apparatus comprises a noise variance determiner (102), a local variance determiner (104), a noise visibility function determiner (106), a Gaussian kernel determiner (108), and a convolver (110). The apparatus removes noise directly from a Displaced Frame Difference, DFD, signal. This novel approach removes noise and miscellaneous high frequency components from the DFD signal without the introduction of the filtering artifacts characteristic of current techniques. By reducing the miscellaneous high frequency components, the present invention is capable of reducing the amount of information that must be encoded by the video encoder without substantially degrading the decoded video sequence.

Abstract: A method and system for estimating the motion within a video sequence provides very accurate estimates of both the displacement vector field, as well as, the boundaries of moving objects. The system comprises a preprocessor (102), a spatially adaptive pixel motion estimator (104), a motion boundary estimator (106), and a motion analyzer (108). The preprocessor (102) provides a first estimate of the displacement vector field, and the spatially adaptive pixel motion estimator (104) provides a first estimate of object boundaries. The motion boundary estimator (106) and the motion analyzer (108) improve the accuracy of the first estimates.

Abstract: The present invention provides a method (600) and system (100) for predicting a differential vector field. The method and system enable the detection and encoding of an area where motion compensating the past image frame to the current image frame, fails. Based on the DFD signal, the present invention detects regions where the motion compensation has failed (102). The boundaries of these regions are encoded and sent to the decoder (104). The intensity values contained in this region, by the current intensity frame, are also encoded and sent to the decoder. Based on the decoded region boundaries, the decoder decodes the intensity values and places them into the correct regions.

Abstract: The present invention provides a method and apparatus for detecting occluded areas in a video frame. A previous displacement vector field, DVF, is motion compensated (402) and used to provide an occlusion test parameter (404) which is compared to an optimal threshold (408) to detect occluded areas. The optimal threshold is calculated based on the previous DVF and a predetermined threshold (406).

Abstract: The present invention provides a method (300) and apparatus (100) for regenerating a dense motion vector field, which describes the motion between two temporally adjacent frames of a video sequence, utilizing a previous dense motion vector field. In this method, a spatial DVF and a temporal DVF are determined (302 and 304) and summed to provide a DVF prediction (306). This method and apparatus enables a dense motion vector field to be used in the encoding and decoding process of a video sequence. This is very important since a dense motion vector field provides a much higher quality prediction of the current frame as compared to the standard block matching motion estimation techniques. The problem to date with utilizing a dense motion vector field is that the information contained in a dense motion field is too large to transmit. The present invention eliminates the need to transmit any motion information.