Apple Inc.

Leland Stanford Junior University

Portalplayer, Inc.

Ke-Chiang C Chu

Hsi-Jung Wu

Jian Lu

Yu Tina Tian

James O Normile

Dulce Beatriz Ponceleon

Chia L Yeh

Daniel W Wright

Roberto Manduchi

Katherine Shu-Wei Wang

Giovanni M Agnoli

Daniel J Culbert

Kevin Bartlett Aitken

James O Normille

Calvin K Lum

In a digital signal processing system, a method for selecting a transform function to apply to an input signal based on characteristics of the signal, and for self-adjusting criteria which are used in selecting a transform function to apply to a subsequent signal. Characteristics are obtained from the signal. The characteristics are compared to adjustable criteria which are used in selecting a transform function. Differing criteria are maintained for the different selectable transform functions. A record is maintained of transform functions selected and the particular characteristics that caused the selection. Based on the ability of a transform function to minimally define the coded signal, an inverse transform function is selected to decode the signal. The criteria used in selecting a transform function to apply to a subsequent signal are adjusted based on a quality measure of the decoded signal and the record of selected transform functions.

Digital image coding system having self-adjusting selection criteria for selecting a transform function

A system and method using edge processing to remove blocking artifacts comprises an edge processor having an image converter for building an edge representation of a received image, a statistics analyzer for compiling a histogram containing edge intensities of the edge representation, a reference calculator for using the histogram to compute reference values corresponding to the blocking artifacts and an artifact remover for identifying and removing the blocking artifacts using the computed reference values.

System and method using edge processing to remove blocking artifacts from decompressed images

A filter system and method are provided that is particular applicable to the resampling of a signal, such as a digital audio signal. The filtering method in accordance with the invention may use a nearest neighbor strategy to reduce the complexity and cost of the filter without reducing the precision of the resampling.

Resampling system and apparatus

Method and system for searching for an optimal codevector

Digital image coding system having self-adjusting selection criteria for

A decompression approach utilizing a single buffer to reduce working memory space decompression requirements. Loading a compressed data file into the 'back end' of a buffer and progressively loading the resulting decompressed data into the 'front end' of the buffer avoids allocating multiple buffers for the decompression process. Using a slop value to increase the size of the allocated buffer beyond the original uncompressed data size avoids inadvertently overwriting not yet uncompressed data still residing in the back end of the single buffer when storing just decompressed data in the front end of the single buffer.

Shared decompression buffer

A communication system encodes input data by comparing the data to records in a lossy codebook to determine the closest match. An index corresponding to the record that most closely matches the input data is retrieved from the codebook and transmitted to a receiver. For a predetermined sampling interval, the communication system collects statistics of the frequency of occurrence of each record matching the input data. The records are sorted in descending order by the frequency of occurrence. Using either a predetermined error rate or a predetermined subtable size, the communication system creates a subtable of the records having the greatest frequency of occurrence. To reduce the search time of finding a record matching the input data, the communication system searches only the subtable for records until the error of the match in the subtable exceeds a preselected threshold or until a preselected period of time has elapsed. The communication system again collects statistics of the frequency of occurrence.

Codebook-based lossy data compression encoding system

A method for improved recursive pitch prediction includes providing a search window for pitch estimates based upon a previously computed pitch, computing pitch estimates for the search window, and determining an optimal pitch from the pitch estimates within the search window for a first predetermined number of frames. The method further includes expanding the search window to a full pitch window after the first predetermined number of frames, and calculating pitch estimates for the full pitch window for a second predetermined number of frames. A system for improved recursive pitch prediction includes a speech generator of speech signals, and a central processing unit coupled to the speech generator. The central processing unit further is capable of coordinating pitch estimation of the speech signals, including providing a search window for pitch estimates based upon a previously computed pitch, calculating pitch estimates for the search window, and determining an optimal pitch from the pitch estimates within the search window for a first predetermined number of frames.

Recursive pitch predictor employing an adaptively determined search

A system for estimating block motion from a previous frame to a current frame, wherein motion vectors have been computed for blocks in the previous frame. The system comprises a P-checkerboard processor, an S-checkerboard processor and a block matching engine. The a P-checkerboard processor selects a first current block from a primary checkerboard pattern, retrieves motion vectors for reference blocks in the previous frame, and uses the retrieved motion vectors to generate a temporal search window. The block matching engine locates in the temporal search window a block which best matches the first current block, and determines the current motion vector from the best matching block to the first current block. Alternatively, the a P-checkerboard processor can use the retrieved motion vectors to interpolate the current motion vector. The S-checkerboard processor selects a second current block from a secondary checkerboard pattern, and uses the current motion vector to generate a spatial dynamic search window. The block matching processor locates in the spatial search window the block which best matches the second current block, and determines the current motion vector from the best matching block to the second current block.

Growing community of inventors

Saratoga, CA, United States of America

Ke-Chiang C Chu