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KR-20260066184-A - METHOD AND APPARATUS FOR VIDEO CODING

KR20260066184AKR 20260066184 AKR20260066184 AKR 20260066184AKR-20260066184-A

Abstract

Aspects of the present disclosure provide methods, apparatuses, and non-transient computer-readable storage media for video encoding/decoding. In the method, prediction information of the current block of the current picture in the encoded bitstream is decoded. The prediction information represents a geometric partitioning mode (GPM) for the current block. The current block is partitioned into two partitions in the GPM mode. Each partition is associated with its own predictor. A weighted index for a sample in the current block is determined based on the position of the sample. A weighting factor is calculated based on the weighted index of the sample according to a mathematical formula that converts the weighted index into a weighting factor. The sample is reconstructed based on the weighting factor and the predictor corresponding to the sample.

Inventors

  • 천, 롄-페이
  • 리, 샹
  • 리, 구이춘
  • 류, 산

Assignees

  • 텐센트 아메리카 엘엘씨

Dates

Publication Date
20260512
Application Date
20201007
Priority Date
20201005

Claims (11)

  1. As a method for video coding in an encoder: A step of partitioning the current block of the current picture based on a geometric partitioning mode (GPM) - said current block is partitioned into two partitions in said GPM, and said partitions are each associated with their own predictor -; A step of determining a weighted index for the sample in the current block based on the location of the sample; A step of calculating the weight factor based on the weight index of the sample according to a mathematical formula that converts the weight index into a weight factor—the mathematical formula includes a right shift operation on the sum of the weight index and an offset value, and the offset value is based on the number of bits shifted by the right shift operation—; and A step of encoding the sample based on the weighting factor and the predictor corresponding to the sample. A method including
  2. In paragraph 1, the above-mentioned calculating step is: A step of generating a result by performing a right shift operation of the mathematical formula on the sum of the weighted index and the offset value; and A step of determining the weight factor by clipping the result of the right shift operation to be within a predefined range based on the clipping function of the above mathematical formula. A method including
  3. A method according to paragraph 2, wherein the number of bits shifted by the right shift operation is based on at least one of the weight index and the size of the cosine table used to calculate the weight index.
  4. In paragraph 1, the step of determining the weighted index is: A step of determining an angle index and a distance index that define the split boundary between the partitions of the current block based on the above GPM; and A step of determining the weighted index for the sample based on the position of the sample, the angle index, and the distance index. A method including
  5. In paragraph 4, the above-mentioned calculating step is: A step of determining a partition index based on the above angle index; and Step of calculating the weighting factor based on the above partition index A method including
  6. In paragraph 5, the above mathematical formula And, Here, And, A method in which idx2wShiftBit represents the number of bits shifted by a right shift operation, weight is the weight factor, partIdx is the partition index, wIdx is the weight index, and Clip3() is a clipping function.
  7. A method according to claim 1, wherein the mathematical formula is a constant function for each interval including an initial value and a plurality of unit step functions.
  8. A method according to claim 7, wherein the initial value is one of the minimum weight factor value or the maximum weight factor value, and the number of the plurality of unit step functions is equal to the total number of different weight factor values minus 1.
  9. A device comprising a processing circuit configured to perform the method of any one of claims 1 to 8.
  10. A non-transient computer-readable storage medium storing a program executable by at least one processor for performing the method of any one of claims 1 to 8.
  11. A non-transient computer-readable storage medium for storing a bitstream of a video generated by a method for video coding in an encoder of any one of claims 1 to 8.

Description

Method and apparatus for video coding [Included as a reference] The present application claims the benefit of priority to U.S. Provisional Application No. 62/953,457, "SIMPLIFICATION FOR GEO INTER BLOCK," filed December 24, 2019, and U.S. Provisional Application No. 62/955,825, "LOOK-UP TABLE FREE METHOD IN WEIGHTING INDEX TO WEIGHT CONVERSION FOR GEO INTER BLOCK," filed December 31, 2019, and the benefit of priority to U.S. Patent Application No. 17/063,149, "METHOD AND APPARATUS FOR VIDEO CODING," filed October 5, 2020. The entire disclosures of the prior applications are hereby incorporated by reference. The present disclosure describes embodiments generally related to video coding. The background description provided in this specification is intended to provide general context for the present disclosure. The research of the inventors currently named—insofar as such research is described in this background section—as well as modes of description that may not qualify as prior art at the time of filing, are not recognized as prior art to the present disclosure, either explicitly or implicitly. Video coding and decoding can be performed using inter-picture prediction with motion compensation. Uncompressed digital video may contain a series of pictures, each having, for example, a spatial dimension of 1920x1080 luminance samples and associated chrominance samples. The series of pictures may have, for example, 60 pictures per second or a fixed or variable picture rate of 60 Hz (informally also known as the frame rate). Uncompressed video has significant bitrate requirements. For example, 1080p60 4:2:0 video at 8 bits per sample (1920x1080 luminance sample resolution at a 60 Hz frame rate) requires bandwidth approaching 1.5 Gbit/s. One hour of such video requires more than 600 gigabytes of storage space. One objective of video coding and decoding may be to reduce redundancy in the input video signal through compression. Compression can help reduce the aforementioned bandwidth or storage requirements by more than two orders of magnitude in some cases. Both lossless and lossy compression, as well as combinations thereof, can be utilized. Lossless compression refers to techniques where an exact copy of the original signal can be reconstructed from the compressed original signal. When using lossy compression, the reconstructed signal may not be identical to the original signal, but the distortion between the original and reconstructed signals is small enough to make the reconstructed signal useful for the intended application. For video, lossy compression is widely used. The amount of acceptable distortion depends on the application. For example, users of certain consumer streaming applications may tolerate higher distortion than users of television distribution applications. The achievable compression ratio may reflect the fact that higher acceptable distortion can yield a higher compression ratio. Video encoders and decoders can utilize techniques from several broad categories, including, for example, motion compensation, transformation, quantization, and entropy coding. Video codec techniques may include techniques known as inter-prediction. For each inter-predicted coding unit (CU), motion parameters include motion vectors, reference picture indices and reference picture list use indices, and additional information to be used for inter-predicted sample generation. Motion parameters may be signaled explicitly or implicitly. When a CU is coded in skip mode, the CU is associated with a single prediction unit (PU), has no significant residual coefficients, and does not have a coded motion vector delta or reference picture index. A merge mode is specified in which motion parameters for the current CU, including spatial and temporal candidates and, for example, additional schedules introduced in VVC, are obtained from neighboring CUs. The merge mode may be applied to any inter-predicted CU as well as to skip mode. An alternative to the merge mode is the explicit transmission of motion parameters. Motion vectors, the corresponding reference picture indices for each reference picture list and reference picture list use flag, and other necessary information are explicitly signaled for each CU. Some inter-prediction coding tools include extended merge prediction, MMVD (merge mode with motion vector difference), AMVP (advanced motion vector prediction mode) with symmetric MVD (motion vector difference) signaling, affine motion compensated prediction, SbTMVP (subblock-based temporal motion vector prediction), AMVR (adaptive motion vector resolution), motion field storage (1/16th luminance sample MV storage and 8x8 motion field compression), BWA (bi-prediction with weighted averaging), BDOF (bi-directional optical flow), DMVR (decoder side motion vector refinement), TPM (triangular partitioning mode), and CIIP (combined inter and intra prediction). In some cases, the merge candidate list is constructed by including the fol