Abstract: A video decoder system affords playback of video information corresponding to a compressed video bitstream which demands less processor performance than would be demanded for decoding the compressed video bitstream itself. One embodiment includes preprocessing and partially decoding the compressed video bitstream, and retaining the partially-decoded information for subsequent playback. In another embodiment the compressed video bitstream is preprocessed and information useful for increasing the processing speed is retained for subsequent playback. Either embodiment may be used alone, or both may be used together. The information useful for increasing the processing speed which is retained for subsequent playback may be retained by creating an intermediate video bitstream which may include partially decoded information from the compressed video bitstream as well as the information useful for increasing the processing speed of the video information.

Abstract: A video decoding system examines a block of DCT coefficients prior to computation of an inverse discrete cosine transform (IDCT) to determine the number of nonzero coefficients. A plurality of IDCT engines are available in the video system including an IDCT engine utilizing fewer computations for a sparse picture and an IDCT engine utilizing fewer computations for a nonsparse picture. The video decoding system selects an IDCT engine to minimize the number of computations performed and to thereby reduce the computational burden of IDCT transformation.

Abstract: A video decoding system that selectively arranges video information within a memory to correspond to macroblocks of video information. Such a system advantageously increases the efficiency of processing video information when decoding compressed video information.

Abstract: A video decoding apparatus and method greatly reduces the computational burden of video decoding by processing several pixels in parallel, thereby reducing the computational load by a factor approximating the number of pixels processed at one time.

Abstract: A method of adaptively performing motion compensation in a video processing apparatus is provided. The video processing apparatus processes macroblocks of compressed video information. Some of these macroblocks have motion vectors associated therewith. The method is conveniently implemented on a general purpose computer in one embodiment. In accordance with the disclosed method, the performance of the processor in the computer is monitored and a measurement of this performance is made. A threshold dependent on the measured processor performance is then set. For those macroblocks which have motion vectors associated therewith, the magnitude of the motion vector is determined. If the magnitude of the motion vector of a particular macroblock exceeds the threshold, then motion compensation is performed on that macroblock. However, if the magnitude of the motion vectors or motion vectors associated with a particular macroblock do not exceed the threshold, then no motion compensation is performed.

Abstract: A decoding system stores frequently-occurring DCT coefficient blocks in a memory and stores pre-computed spatial domain kernels which correspond to the stored DCT coefficient blocks. The video system examines a block of DCT coefficients prior to computation of an inverse discrete cosine transform (IDCT) to determine whether the block is substantially similar to a stored frequently-occurring DCT coefficient block. If so, the spatial domain kernel corresponding to the frequently-occurring DCT block is utilized in the decoded picture, bypassing computation of the IDCT.

Abstract: A video system examines the transform domain content of various spatially related blocks in a compressed video bitstream to determine whether predetermined types of similarities exist between multiple blocks. When certain selected similarities are found, the video system spatially combines the blocks in a predetermined manner. In some embodiments, DCT coefficients of a plurality of blocks are averaged to form one averaged block and the averaged block is inverse discrete cosine transformed. The averaged and IDCT transformed block is written to the display at the position of each of the averaged blocks. In some embodiments, a representative block of a plurality of DCT coefficient blocks is selected and inverse discrete cosine transformed. The selected and IDCT transformed block is written to the display at the position of each of the plurality of blocks.

Abstract: An video decoder system, such as for use with MPEG video compression, uses a previous B-frame as an additional prediction source for the current B-frame. In one embodiment, a given block within a current B-frame "N" reuses IDCT result terms from the previous B-frame "N-1" if they are determined to be "similar enough" to the anticipated IDCT result terms which would otherwise need to be computed. For a given block, each of the "M" lowest-frequency DCT coefficients for B-frame "N" and B-frame "N-1" are respectively compared: if they differ by less than a similarity threshold value, then the IDCT result terms from the previous B-frame "N-1" are reused without further computation. The similarity threshold may be adaptively adjusted to reduce the computational burden of video decompression, while affording a gradual degradation of picture quality, rather than wholesale skipping of entire frames.

Abstract: A method of pixel averaging is disclosed which advantageously employs a relatively low number of registers, relatively few memory accesses and a relatively low number of steps. A first register is loaded with a first sequence of pixel values which are to be averaged with a second sequence of pixel values loaded into a second register. The pixel values of the first sequence are stored in respective segments of the first register and the pixel values of the second sequence are stored in respective segments of the second register. The pixel values in the first and second registers are shifted to the right by one. The most significant bit of each of the segments of the first register and the most significant bit of each of the segments of the second register are masked. First masked quotients are thus obtained in each of the segments of the first register and second masked quotients are thus obtained in each of the segments of the second register.

Abstract: A video decoder system affords playback of video information corresponding to a compressed video bitstream while demanding less processor performance than traditionally required. One method embodiment includes preprocessing the compressed video bitstream to generate a secondary video bitstream which includes information useful for decoding the compressed video bitstream in a more processor efficient manner than would be achievable by decoding the compressed video bitstream alone. The secondary video bitstream is then stored for use during a subsequent playback mode. When in the playback mode, the compressed video bitstream is decoded by processing both the compressed video bitstream together with the secondary video bitstream. The secondary video bitstream may be stored on a system hard disk where it may be read much faster than if stored on a CD-ROM and may be deleted when not needed.

Abstract: An video decoder system, such as for use with MPEG video compression, uses a previous B-frame as an additional prediction source for the current B-frame, along with the past and future reference frames as defined by the MPEG specification. In one embodiment a given macroblock within a current B-frame "N" reuses pixel values from the previous B-frame "N-1" if they are "similar enough" to the anticipated pixels which would otherwise need to be computed. For a given macroblock, motion vectors for both B-frames are compared: if they differ by less than a similarity threshold value, then the pixel values from the previous B-frame are reused without further computation. The similarity threshold may be adaptively adjusted to reduce the computational burden of video decompression, while affording a gradual degradation of picture quality, rather than wholesale skipping of entire frames.

Abstract: A video decompression system utilizes multiple independent input buffers so that input/output operations and processing take place concurrently, nearly continuously and at a rate that is substantially equal to a selected maximum access rate of the storage device. Consequently, the data rate of the video decompression system is optimized with respect to the rate of data accessing. The video decompression system adaptively sets input buffer parameters as a function, for example, of processor capabilities, bitstream characteristics, drive latency and access time, and file I/O overhead.

Abstract: A method for decomposing signals into efficient time-frequency representations for data compression and recognition which uses adaptable wavelet basis functions and concentrates a signal or image's information to a higher degree than methods based on the discrete fourier transform, the discrete cosine transform, the standard wavelet transform and known adaptive transform techniques. The purpose of the present invention is to enable data signals and images to be stored and transmitted very efficiently. The time-frequency plane is broken up into subspaces. The method determines the optimum basis function for each of the subspace regions. Basis functions are chosen such that much of the information in the signal is contained in a small number of coefficients. The resulting coefficients form a set that represents the signal in the most concentrated manner.

Abstract: A method and apparatus for locating objects within a large range and with high accuracy through the use of a multiwave technique utilizing simultaneous phase measurements of interfering reflected and non-reflected optical radiation, comprising a plurality of different wavelengths and associated reference signals wherein the interfering reflected and non-reflected optical radiation create various heterodyne signals each having the same frequency as the associated reference signal.