Sample adaptive offset control
    251.
    发明授权

    公开(公告)号:US11363264B2

    公开(公告)日:2022-06-14

    申请号:US16880084

    申请日:2020-05-21

    Applicant: Apple Inc.

    Abstract: Offset values, such as Sample Adaptive Offset (SAO) values in video coding standards such as the High Efficiency Video Coding standard (HEVC), may be improved by performing calculations and operations that improve the preciseness of these values without materially affecting the signal overhead needed to transmit the more precise values. Such calculations and operations may include applying a quantization factor to a video sample and at least some of its neighbors, comparing the quantized values, and classifying the video sample as a minimum, maximum, or one of various types of edges based on the comparison. Other sample range, offset mode, and/or offset precision parameters may be calculated and transmitted with metadata to improve the precision of offset values.

    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.

    Adaptive color space transform coding

    公开(公告)号:US11184613B2

    公开(公告)日:2021-11-23

    申请号:US16822969

    申请日:2020-03-18

    Applicant: Apple Inc.

    Abstract: An encoder system may include an analyzer that analyzes a current image area in an input video to select a transform. A selectable residue transformer, controlled by the analyzer, may perform the selectable transform on a residue image generated from the current image area and a predicted current image area, to generate a transformed residue image. An encoder may encode the transformed residue image to generate output data. The analyzer controls the encoder to encode information to identify the selectable transform and to indicate that the selectable transform for the current image area is different from a transform of a previous image area of the input video. A decoder system may include components appropriate for decoding the output data from the encoder system.

    Predicting attributes for point cloud compression according to a space filling curve

    公开(公告)号:US11132818B2

    公开(公告)日:2021-09-28

    申请号:US16586785

    申请日:2019-09-27

    Applicant: Apple Inc.

    Abstract: Attributes for point cloud compression may be predicted according to a space filling curve. An order for selecting points of a point cloud to be compressed in order to predict attributes of the points may be determined according to values of a space filling curve applied to spatial information for the points. A point of the point cloud may be selected according to the determined ordering. A prediction technique may be performed with respect to the selected point based on a set of neighboring points in the point cloud also selected according to the ordering. Predicted attribute values and correction values may be determined for the predicted values. The correction values may be encoded as part of a compressed version of the point cloud.

    Adaptive Distance Based Point Cloud Compression

    公开(公告)号:US20210264640A1

    公开(公告)日:2021-08-26

    申请号:US17318273

    申请日:2021-05-12

    Applicant: Apple Inc.

    Abstract: A system comprises an encoder configured to compress attribute information for a point cloud and/or a decoder configured to decompress compressed attribute for the point cloud. To compress the attribute information, attribute values are predicted using one of a plurality of prediction strategies, wherein a selected prediction strategy is selected based at least in part on attribute variability of points in a neighborhood of points. A decoder follows a similar prediction process. Also, attribute correction values may be determined to correct predicted attribute values and may be used by a decoder to decompress a point cloud, wherein the decoder applies the same prediction strategy applied at the encoder.

    Hierarchical Point Cloud Compression

    公开(公告)号:US20210258617A1

    公开(公告)日:2021-08-19

    申请号:US17163204

    申请日:2021-01-29

    Applicant: Apple Inc.

    Abstract: A system comprises an encoder configured to compress attribute information for a point cloud and/or a decoder configured to decompress compressed attribute information for the point cloud. To compress the attribute information, multiple levels of detail are generated based on an ordering of the points according to a space filling curve and attribute values are predicted. The attribute values may be predicted simultaneously while points are being assigned to different levels of detail. A decoder follows a similar prediction process based on level of details. Also, attribute correction values may be determined to correct predicted attribute values and may be used by a decoder to decompress a point cloud compressed using level of detail attribute compression. In some embodiments, attribute correction values may take into account an influence factor of respective points in a given level of detail on attributes in other levels of detail.

    MULTI-STAGE BLOCK CODING
    259.
    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.

    SCALABILITY OF MULTI-DIRECTIONAL VIDEO STREAMING

    公开(公告)号:US20210227236A1

    公开(公告)日:2021-07-22

    申请号:US17221299

    申请日:2021-04-02

    Applicant: Apple Inc.

    Abstract: Aspects of the present disclosure provide techniques for reducing latency and improving image quality of a viewport extracted from multi-directional video communications. According to such techniques, first streams of coded video data are received from a source. The first streams include coded data for each of a plurality of tiles representing a multi-directional video, where each tile corresponding to a predetermined spatial region of the multi-directional video, and at least one tile of the plurality of tiles in the first streams contains a current viewport location at a receiver. The techniques include decoding the first streams and displaying the tile containing the current viewport location. When the viewport location at the receiver changes to include a new tile of the plurality of tiles, retrieving and decoding first streams for the new tile, displaying the decoded content for the changed viewport location, and transmitting the changed viewport location to the source.

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