Apple Inc.

Stephan Lachowsky

Tyson J Bergland

Karthik Ramani

Peter F Holland

Mahesh B Chappalli

Christopher P Tann

Guy Côté

Justin A Hensley

Anthony P DeLaurier

Davoud A Jamshidi

Techniques are disclosed relating to compression of pixel data using different quantization for different regions of a block of pixels being compressed. In some embodiments, compression circuitry is configured to determine, for multiple components included in pixels of the block of pixels being compressed, respective smallest and greatest component values in respective regions of the block of pixels. The compression circuitry may determine, based on the determined smallest and greatest component values, to use a first number of bits to represent delta values relative to a base value for a first component in a first region and a second, different number of bits to represent delta values relative to a base value for a second component in the first region. The compression circuitry may then quantize delta values for the first and second components of pixels in the first region of the block of pixels using the determined first and second numbers of bits. In some embodiments, the compression circuitry determines whether to provide cross-component bit sharing within a region.

Lossy compression techniques

Techniques are disclosed relating to data compression. In some embodiments, compression circuitry determines, at least partially in parallel for multiple different lossless compression techniques, amounts of data needed to represent, using a given lossless compression technique of the multiple lossless compression techniques, individual pixels in a set of pixels being compressed. The compression techniques may include neighbor, origin, and gradient techniques, for example. The compression circuitry may select one of the compression techniques based on comparison, among the compression techniques, of sums of: the determined amount of data for an individual pixel for a given lossless compression technique and compression metadata size for a given lossless compression technique. The compression circuitry may generate and store information that encodes values for the set of pixels using the selected compression technique.

Lossless compression techniques

An electronic display pipeline may process image data for display on an electronic display. The electronic display pipeline may include burn-in compensation statistics collection circuitry and burn-in compensation circuitry. The burn-in compensation statistics collection circuitry may collect image statistics based at least in part on the image data. The statistics may estimate a likely amount of non-uniform aging of the sub-pixels of the electronic display. The burn-in compensation circuitry may apply a gain to sub-pixels of the image data to account for non-uniform aging of corresponding sub-pixels of the electronic display. The applied gain may be based at least in part on the image statistics collected by the burn-in compensation statistics collection circuitry.

Burn-in statistics and burn-in compensation

Techniques are disclosed relating to data compression. In some embodiments, compression circuitry determines, at least partially in parallel for multiple different lossless compression techniques, a number of bits needed to represent a least compressible pixel, using that technique, in a set of pixels being compressed. The compression techniques may include neighbor, origin, and gradient techniques, for example. The compression circuitry may select one of the compression techniques based on the determined numbers of bits for the multiple compression techniques and corresponding header sizes. In some embodiments, the compression circuitry determines, for multiple regions of pixels in the set of pixels, for ones of the compression techniques, a region number of bits needed to represent a least compressible pixel, using that technique. The selection of a compression technique may be further based on region numbers of bits.

Systems and methods for improving operation of an electronic device that includes a processing pipeline. The processing pipeline includes a prediction block that determines prediction residuals based on difference between uncompressed image data corresponding with a pixel tile and prediction of a first pixel group in the pixel tile and difference between the uncompressed image data and prediction of a second pixel group in the pixel tile, a run encode block that replaces a first of the prediction residuals with an escape value and a second of the prediction residuals with a run length value when a run starting in the first pixel group and continuing into the second pixel group is detected, and an entropy encode block that generates compressed image data corresponding with the pixel tile by entropy encoding a third of the prediction residuals, the escape value, and the run length value when the run is detected.

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San Francisco, CA, United States of America

Stephan Lachowsky