Smoothed directional and DC intra prediction

    公开(公告)号:US11388419B2

    公开(公告)日:2022-07-12

    申请号:US16834693

    申请日:2020-03-30

    Applicant: Apple Inc.

    Abstract: Improved video coding techniques include deriving prediction pixel blocks for use in intra-coding video and combined inter- and intra-coding video. In a first aspect, the techniques may include deriving value(s) for pixel location(s) of the prediction pixel block by, when a prediction direction vector assigned to the prediction vector points to quadrants I or III of a Cartesian plane, deriving the pixel location's value from pixel values in two regions of previously-decoded pixel data intercepted by extending the prediction direction vector in two opposite directions through the pixel location. When the prediction direction vector points toward quadrants II of the Cartesian plane, deriving the pixel location's value from pixel values in one region intercepted by the prediction direction vector through the pixel location, and from a second region intercepted by a vector that is orthogonal to the prediction direction vector.

    Reference picture management and list construction

    公开(公告)号:US11196988B2

    公开(公告)日:2021-12-07

    申请号:US16669385

    申请日:2019-10-30

    Applicant: Apple Inc.

    Abstract: Techniques for encoding video with motion compensation include a compressed bitstream syntax that includes a list of all motion prediction reference frames without distinguishing between short-term reference frame and long-term reference frames. The list of reference frames may be provided in a slice header and may apply to encoded data video data within the corresponding slice. The list may be prefaced with a single number indicating the total number of reference frames. In an aspect delta POC reference numbers may be encoded with a flag indicating the sign of the delta POC when the absolute value of the POC is not equal to zero. In another aspect, a flag may be encoded for every reference frame indicating if POC information should be used when scaling prediction references, and a weighting parameter may be included when POC information should be used.

    MULTI-STAGE BLOCK CODING
    14.
    发明申请

    公开(公告)号:US20210243455A1

    公开(公告)日:2021-08-05

    申请号:US17167413

    申请日:2021-02-04

    Applicant: Apple Inc.

    Abstract: A multi-stage coding method includes receiving an input block of data for encoding and one or more previously coded samples associated with the input block. The input block is segmented into at least a first sub-region and a second sub-region. A prediction for the first sub-region is generated based on the one or more previously coded samples. Residual data for the first sub-region is obtained using the prediction for the first sub-region. A reconstruction of the first sub-region is generated using the residual data for the first sub-region and the prediction for the first sub-region. A prediction for the second sub-region is generated using the reconstruction of the first sub-region. Residual data for the second sub-region is obtained using the prediction for the second sub-region. The input block is encoded based in part on the residual data for the first region and the residual data for the second region.

    Deep Quality Enhancement of Adaptive Downscaled Coding for Image Compression

    公开(公告)号:US20200053362A1

    公开(公告)日:2020-02-13

    申请号:US16100310

    申请日:2018-08-10

    Applicant: Apple Inc.

    Abstract: Techniques are disclosed for coding image data adaptively at different levels of downscaling. Such techniques may involve partitioning input data into pixel blocks for coding and performing content analysis on the pixel blocks. The pixel blocks may be input to block coders that operate at different pixel block sizes, which may code the pixel blocks input to them at their respective sizes. Except when a block coder operates at the partitioning size, block coders that operate at different pixel block sizes may perform downscaling of the pixel blocks to match their size with the block coders' respective coding size. A block decoder may invert the coding operations performed by the block coders, decoding coded image data at respective pixel block sizes, then upscaling decoded image data obtained therefrom to a common pixel block size. Image reconstruction may synthesize a resultant image from the decode pixel block data output by the decoders. Quality enhancements may be added by neural network processing systems that have been trained to other segmented images.

    Reference picture re-sampling
    16.
    发明授权

    公开(公告)号:US12058361B2

    公开(公告)日:2024-08-06

    申请号:US17723788

    申请日:2022-04-19

    Applicant: Apple Inc.

    CPC classification number: H04N19/503 H04N19/82 H04N19/86

    Abstract: Predictive coding techniques may include resampling of reference pictures, where various coding parameters are determined based on the resolution(s) or pixel format(s) of the prediction references. In a first aspect, lists of weights for use in weighted prediction are based on the resolution(s) of prediction references. In a second aspect, resampling filter parameters are selected based on the resolutions of prediction references. In a third aspect, deblocking filter parameters are based on the resolution(s) of prediction references.

    SMOOTHED DIRECTIONAL AND DC INTRA PREDICTION

    公开(公告)号:US20220303554A1

    公开(公告)日:2022-09-22

    申请号:US17837846

    申请日:2022-06-10

    Applicant: Apple Inc.

    Abstract: Techniques are disclosed for deriving prediction pixel blocks for use in intra-coding video and combined inter- and intra-coding video. In a first aspect, the techniques may include deriving value(s) for pixel location(s) of the prediction pixel block by, when a prediction direction vector assigned to the prediction vector points to quadrants I or III of a Cartesian plane, deriving the pixel location's value from pixel values in two regions of previously-decoded pixel data intercepted by extending the prediction direction vector in two opposite directions through the pixel location. When the prediction direction vector points toward quadrants II of the Cartesian plane, deriving the pixel location's value from pixel values in one region intercepted by the prediction direction vector through the pixel location, and from a second region intercepted by a vector that is orthogonal to the prediction direction vector.

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