CN-119653082-B - Constrained and adjusted application of combined inter and intra prediction modes

CN119653082BCN 119653082 BCN119653082 BCN 119653082BCN-119653082-B

Abstract

A method of constraining and adjusting application of combined inter-and intra-prediction (CIIP) modes employed in video codec standards, such as current universal video codec VVC, is performed at a computing device. In one method, a computing device determines whether to apply decoder-side motion vector refinement (DMVR) and bi-directional optical flow (BDOF) to bi-prediction blocks. In another approach, a computing device determines whether each of neighboring CUs of a CU ("current CU") are individually CIIP encoded and, in forming a Most Probable Mode (MPM) candidate list for the current CU using intra-modes of CUs of neighboring CIIP encoded, employs a unified criterion that is independent of determining whether the current CU is intra-coded or CIIP encoded.

Inventors

XIU XIAOYU
CHEN YIWEN
WANG XIANGLIN

Assignees

北京达佳互联信息技术有限公司

Dates

Publication Date: 20260512
Application Date: 20200312
Priority Date: 20190312

Claims (7)

1. A video decoding method, comprising: Obtaining a first reference picture and a second reference picture associated with a current block, wherein the first reference picture precedes a current picture and the second reference picture follows the current picture in display order; determining to apply a decoder-side motion vector refinement operation to the current block in response to the combined inter and intra prediction flags for the current block indicating that combined inter and intra prediction is not applied to the current block; Determining to apply a bi-directional optical flow operation to the current block in response to the combined inter-and intra-prediction flag for the current block indicating that combined inter-and intra-prediction is not applied to the current block; based on the first reference picture, the second reference picture, and the determination to apply the decoder-side motion vector refinement operation and the determination to apply the bidirectional optical flow operation, calculating a bidirectional prediction of the current block, Wherein calculating the bi-prediction of the current block comprises: Adjusting a first motion vector and a second motion vector to generate a first prediction and a second prediction, wherein the first motion vector is from the current block to a reference block in the first reference picture that precedes the current picture in display order, and the second motion vector is from the current block to a reference block in the second reference picture that follows the current picture in display order; calculating a first horizontal gradient value and a first vertical gradient value associated with the first prediction, and A second horizontal gradient value and a second vertical gradient value associated with the second prediction are calculated.
2. The method of claim 1, the calculating bi-prediction of the current block based on the first reference picture, the second reference picture, and a determination to apply the decoder-side motion vector refinement operation and a determination to apply the bi-optical flow operation, comprising: A bi-prediction of the current block is calculated based on the first prediction, the second prediction, the first horizontal gradient value and first vertical gradient value, and the second horizontal gradient value and second vertical gradient value.
3. A video encoding method, comprising: Obtaining a first reference picture and a second reference picture associated with a current block, wherein the first reference picture precedes a current picture and the second reference picture follows the current picture in display order; Applying a decoder-side motion vector refinement operation to the current block when the combined inter and intra prediction flags for the current block indicate that the combined inter and intra prediction is not applied to the current block; applying a bi-directional optical flow operation to the current block when a combined inter-and intra-prediction flag for the current block indicates that combined inter-and intra-prediction is not applied to the current block; based on the first reference picture, the second reference picture, and the determination to apply the decoder-side motion vector refinement operation and the determination to apply the bidirectional optical flow operation, calculating a bidirectional prediction of the current block, Wherein calculating the bi-prediction of the current block comprises: Adjusting a first motion vector and a second motion vector to generate a first prediction and a second prediction, wherein the first motion vector is from the current block to a reference block in the first reference picture that precedes the current picture in display order, and the second motion vector is from the current block to a reference block in the second reference picture that follows the current picture in display order; calculating a first horizontal gradient value and a first vertical gradient value associated with the first prediction, and A second horizontal gradient value and a second vertical gradient value associated with the second prediction are calculated.
4. The method of claim 3, the calculating bi-prediction of the current block based on the first reference picture, the second reference picture, and a determination to apply the decoder-side motion vector refinement operation and a determination to apply the bi-optical flow operation, comprising: A bi-prediction of the current block is calculated based on the first prediction, the second prediction, the first horizontal gradient value and first vertical gradient value, and the second horizontal gradient value and second vertical gradient value.
5. A computing device, comprising: Storage medium, and One or more processors coupled to the storage medium, wherein the one or more processors are configured to perform the method of any of claims 1-4.
6. A method of storing a bitstream, comprising: performing the video coding method of any of claims 3-4 to generate a bitstream, and The bit stream is stored.
7. A non-transitory computer-readable storage medium storing instructions and a bitstream formed of the instructions, which when executed by a computing device having one or more processors, cause the one or more processors to perform the video encoding method of any of claims 3-4.

Description

Constrained and adjusted application of combined inter and intra prediction modes The application is a divisional application with application number of 202080020524.0, application date of 2020, 3/12/titled of application of constrained and regulated combined inter-and intra-prediction modes. Cross Reference to Related Applications The present application claims the benefit of U.S. provisional patent application Ser. No. 62/817,503, filed on 3/12 of 2019. The entire disclosure of the above application is incorporated herein by reference in its entirety. Technical Field The present disclosure relates generally to video codec and compression. More particularly, the present disclosure relates to systems and methods for performing video coding using constraints and adjustments for application of Combined Inter and Intra Prediction (CIIP) modes. Background This section provides background information related to the present disclosure. The information contained in this section should not necessarily be construed as prior art. Any of a variety of video codec techniques may be used to compress video data. Video coding may be performed according to one or more video coding standards. Some illustrative video coding standards include general video coding (VVC), joint exploration test model (JEM) coding, high efficiency video coding (h.265/HEVC), advanced video coding (h.264/AVC), and Motion Picture Experts Group (MPEG) coding. Video coding typically employs prediction methods (e.g., inter-frame prediction, intra-frame prediction, etc.) that exploit redundancy inherent in a video image or sequence. One goal of video codec technology is to compress video data into a form that uses a lower bit rate while avoiding or minimizing degradation of video quality. Prediction methods used in video codecs typically include performing spatial (intra) prediction and/or temporal (inter) prediction to reduce or remove redundancy inherent in video data, and are typically associated with block-based video codecs. BRIEF SUMMARY OF THE PRESENT DISCLOSURE This section provides a general summary of the disclosure, and is not a comprehensive disclosure of its full scope or all of its features. According to a first aspect of the disclosure, a video codec method is performed at a computing device having one or more processors and memory storing a plurality of programs to be executed by the one or more processors. The method includes dividing each picture in the video stream into a plurality of blocks or CUs. The method includes an operation of bypassing one or more inter-prediction processes in generating inter-prediction samples during application CIIP modes to a CU when the CU is bi-directionally predicted. The one or more bypassed inter prediction processes include decoder-side motion vector refinement (DMVR) and bi-directional optical flow (BDOF). According to a second aspect of the present disclosure, a video codec method is performed at a computing device having one or more processors and memory storing a plurality of programs to be executed by the one or more processors. The method includes dividing each picture in the video stream into a plurality of blocks or CUs. The method also includes identifying a CU that is a candidate for application of CIIP modes. The method further includes determining whether the CU identified as a candidate for application of CIIP modes is bi-predicted or uni-predicted. The method further includes restricting CIIP application of the mode to the CU based on the determination. According to a third aspect of the present disclosure, a video codec method is performed at a computing device having one or more processors and memory storing a plurality of programs to be executed by the one or more processors. The method includes dividing each picture in a video stream into a plurality of blocks or Coding Units (CUs). The method further includes deriving an MPM candidate list for each CU. The method also includes determining whether each of the neighboring CUs of the CU ("current CU") are each a block that is CIIP codec. The method further includes, for each of the CIIP codec's neighboring CUs, employing a unified criterion that is independent of determining whether the current CU is intra-codec or CIIP codec in forming an MPM candidate list for the current CU using intra-modes of the neighboring CUs. According to a fourth aspect of the application, a computing device includes one or more processors, memory, and a plurality of programs stored in the memory. These programs, when executed by one or more processors, cause the computing device to perform operations as described above. According to a fifth aspect of the application, a non-transitory computer readable storage medium stores a plurality of programs for execution by a computing device having one or more processors. These programs, when executed by one or more processors, cause the computing device to perform operations as described above. Drawings Hereinafter