Methods, systems, and computer programs for improved quality video compression. Image quality from MPEG-style video coding may be improved by preserving a higher number of bits during intermediate encoding and decoding processing steps. Problems of inverse discrete cosine transform (IDCT) mismatch can be eliminated by exactly matching the IDCT function numerical algorithm of the decoder to the IDCT function numerical algorithm used for the decoding portion of the encoder. Also included is an application of high precision compression to wide dynamic range images by extending the range of the “quantization parameter” or “QP”. The extension of QP may be accomplished either by increasing the range of QP directly, or indirectly through a non-linear transformation. Also included is an application of extended intermediate processing precision and an extended QP range to reduced contrast regions of an image to extend the precision with which the low-contrast portions are compression coded.

High precision encoding and decoding of video images

A video system for coding a stream of video data that includes a stream of video frames divides each video frame into a matrix of a plurality of subblocks, wherein each subblock includes a plurality of pixels. The video system operates in accordance with nine prediction modes. Each prediction mode determines a prediction mode according to which a present subblock is to be coded. One of the nine prediction modes is selected to encode the present subblock, wherein the selected prediction mode provides for a minimum error value in the present subblock.

System and method for intracoding video data

A system and method for decoding digital video by processing multiple regions of an image in parallel, even when there are dependencies between rows in the image, are disclosed. The method generally involves decoding multiple rows concurrently, with the start of decoding of a given row being delayed until portions of the other rows on which the given row depends have been decoded. The system generally comprises parallel processors, with one processor typically decoding one row and another processor typically decoding the row above it. In accordance with the present invention, however, any number or type of processors can decode, or perform decoding functions on, the image in parallel.

System and method for multi-row decoding of video with dependent rows

A wavelet transform system and an inverse wavelet transform system are disclosed that respectively implement a wavelet transform and an inverse wavelet transform. Semi-orthogonal standard wavelets are used as the basic wavelets in the wavelet transform and the inverse wavelet transform. As a result, two finite sequences of decomposition coefficients are used for decomposition in the wavelet transform. Furthermore, two finite sequences of reconstruction coefficients that are derived from the two finite sequences of decomposition coefficients are used for reconstruction in the inverse wavelet transform. The finite sequences of decomposition and reconstruction coefficients are not infinite sequences of coefficients that have been truncated. Furthermore, in one embodiment, downsampling is not used in the wavelet transform and upsampling is not used in the inverse wavelet transform.

System and method for performing wavelet and inverse wavelet transformations of digital data using semi-orthogonal wavelets

An architecture component for use in performing a wavelet transform of a sampled signal, and an architecture including such components are disclosed. The architecture component includes a multiplier, and a multiplexor to multiplex a number n of filter coefficients onto the multiplier. The multiplier processes n consecutive samples with consecutive coefficients, successive multiplier outputs being stored for subsequent processing to generate an output of the filter after every n samples. The wavelet transform may be a discrete wavelet transform or a wavelet packet decomposition. The architecture component may be configured to multiplex two or more coefficients onto a multiplier. Embodiments are disclosed in which the components are derived from a parameterized description in a hardware description language.

Implementation of wavelet functions in hardware

A system and method implementing a fast wavelet transform by shifting a pair of pixels into a single shift register and using a multimode quadrature mirror filter to eliminate the need of downsampling the filtered signals and to decrease the area required to implement the device on a semiconductor chip

System and method for implementing the fast wavelet transform

A video encoder typically includes a preprocessor, a frame store, a motion compensator, and a compression module. The preprocessor converts an incoming digital video signal to image macroblocks. The frame store stores the macroblocks from anchor frames, and the motion compensator searches neighborhoods in anchor frames for best matches to macroblocks from a current frame. The compression module receives a vector from the motion compensator indicative of the best match and uses it to compress the macroblocks from the current frame. The compressed macroblocks are provided as components of a compressed video output bitstream. To perform the neighborhood search, the motion compensator accesses many neighborhood macroblocks from the anchor frame for each macroblock from the current frame. To reduce the number of memory accesses, the motion compensator caches the neighborhood macroblocks. Since the search neighborhoods for adjacent macroblocks overlap, caching is effective. The effectiveness of caching may be increased by altering the order in which macroblocks from the current anchor frame are processed. This advantageously reduces the number of neighbourhood macroblocks from the anchor frame added to the cache for each neighborhood search, thereby providing for reduced requirement for memory bandwidth of the frame store.

Video encoder having reduced memory bandwidth requirements

Method and apparatus for two row macroblock decoding improves caching efficiency reducing memory bandwidth requirements while simultaneously enabling encoded video information to be decoded in a fast and efficient manner to produce specific results required for MPEG2 video decoding.

Method and apparatus for two-row macroblock decoding to improve caching efficiency

A method derives edge extensions for wavelet transforms and inverse wavelet transforms of two-dimensional images. The method overcomes the necessity of side computations by treating the two-dimensional matrix of values as a one-dimensional array of values. The use of a one-dimensional array reduces the required flushing and loading of registers by allowing the flushing and loading to be performed in between frames, rather than in between rows or columns of the matrix.

Method to derive edge extensions for wavelet transforms and inverse wavelet transforms

A method and system for decoding compressed MPEG2 bitstream video data utilizing a two row macroblock cache memory and algorithm for determining data overlap between a stored reference macroblock and a stored current macroblock to improve memory bandwidth requirements while producing specific decoding results required for MPEG2 video information.

Mody Lempel

Papers

System and method for implementing the fast wavelet transform

Video encoder having reduced memory bandwidth requirements

Method and apparatus for two-row macroblock decoding to improve caching efficiency

Method to derive edge extensions for wavelet transforms and inverse wavelet transforms

Method and apparatus for two-row decoding of MPEG video