公开(公告)号：US20220116624A1

公开(公告)日：2022-04-14

申请号：US17645608

申请日：2021-12-22

Applicant: Huawei Technologies Co., Ltd.

Inventor： Sriram SETHURAMAN ,  Jeeva Raj A ,  Sagar KOTECHA

IPC: H04N19/137 ,  H04N19/105 ,  H04N19/132 ,  H04N19/159 ,  H04N19/176

Abstract: A method for bi-directional optical flow prediction based on reference sample values from sample positions belonging to an extended region of a predicted block used in the bi-directional optical flow prediction of a current block is provided, wherein sub-pixel positions in the extended region of the predicted block in the reference picture are rounded to obtain integer pixel sample positions in the reference picture, wherein the reference sample values at the obtained integer pixel sample positions in the reference picture are used in the computation of boundary sample gradients corresponding to the boundaries of the predicted block in the reference picture.

公开(公告)号：US20210203946A1

公开(公告)日：2021-07-01

申请号：US17249771

申请日：2021-03-12

Applicant: HUAWEI TECHNOLOGIES CO., LTD.

Inventor： Sriram SETHURAMAN ,  Jeeva Raj A ,  Sagar KOTECHA

IPC: H04N19/137 ,  H04N19/159 ,  H04N19/105 ,  H04N19/70 ,  H04N19/52 ,  H04N19/176

Abstract: A method for inter-prediction of a current image block in a current picture of a video is provided. The method includes determining whether a first temporal distance (such as TD0) is equal to a second temporal distance (such as TD1), wherein the first temporal distance is represented in terms of a difference between a picture order count value of the current picture and a picture order count value of a first reference image; and the second temporal distance is represented in terms of a difference between a picture order count value of a second reference image and the picture order count value of the current picture; and performing no motion vector refinement (DMVR) procedure when it is determined that the first temporal distance (TD0) is not equal to the second temporal distance (TD1). Thus the DMVR procedure is restricted to only the image block with equal-distance references.

公开(公告)号：US20240259583A1

公开(公告)日：2024-08-01

申请号：US18613596

申请日：2024-03-22

Applicant: HUAWEI TECHNOLOGIES CO., LTD.

Inventor： Sriram SETHURAMAN ,  Sagar KOTECHA ,  Jeeva Raj A

IPC: H04N19/513 ,  H04N19/107 ,  H04N19/132 ,  H04N19/139 ,  H04N19/176

CPC classification number: H04N19/513 ,  H04N19/107 ,  H04N19/132 ,  H04N19/139 ,  H04N19/176

Abstract: A bidirectional optical flowing prediction method includes obtaining an initial motion vector pair for a current block, obtaining a forward and a backward prediction block according to the forward motion vector and a backward prediction block according to the initial motion vector pair, and calculating gradient parameters for a current sample in the current block. The method further includes obtaining at least two sample optical flow parameters, including a first parameter and a second parameter, for the current sample based on the gradient parameters, obtaining block optical flow parameters based on sample optical flow parameters of samples in the current block, and obtaining a prediction value of the current block. One of the block optical flow parameters is obtained by multiplying the first parameter and a sign function of the second parameter, and the sign function is a piecewise function with at least three subintervals.

公开(公告)号：US20220060690A1

公开(公告)日：2022-02-24

申请号：US17466930

申请日：2021-09-03

Applicant: Huawei Technologies Co., Ltd.

Inventor： Sriram SETHURAMAN ,  Sagar KOTECHA ,  Jeeva Raj A

IPC: H04N19/105 ,  H04N19/137 ,  H04N19/132 ,  H04N19/159 ,  H04N19/176

Abstract: A method for inter prediction of a block of a picture and corresponding apparatus are provided. The method comprises: determining a first prediction block based on an initial first motion vector of a current block in a first reference picture, so as to obtain a first extension block; obtaining from the first reference picture, one or more first reference blocks each of which is associated with a combination of the initial first motion vector and one of motion vector offsets; obtaining a target motion vector offset with a smallest cost among the motion vector offsets; determining for the current block, a refined first motion vector which is a combination of the initial first motion vector and the target motion vector offset; and obtaining a refined prediction block of the current block based on the refined first motion vector, thereby improving coherence of refined motion vectors to achieve higher coding efficiencies.

公开(公告)号：US20210400259A1

公开(公告)日：2021-12-23

申请号：US17466129

申请日：2021-09-03

Applicant: HUAWEI TECHNOLOGIES CO., LTD.

Inventor： Sriram SETHURAMAN ,  Semih ESENLIK ,  Jeeva Raj A ,  Sagar KOTECHA

IPC: H04N19/105 ,  H04N19/132 ,  H04N19/137 ,  H04N19/159 ,  H04N19/46 ,  H04N19/176

Abstract: The present disclosure provides an inter prediction method, comprising the steps of obtaining an initial motion vector and a reference picture for bi-prediction; obtaining sets of candidate sample positions in the reference picture according to the initial motion vector and candidate motion vectors, wherein each candidate motion vector is derived by the initial motion vector and a respective motion vector offset, and wherein each set of candidate sample positions corresponds to each candidate motion vector; obtaining a respective set of sample positions from each set of candidate sample positions; computing a matching cost for each candidate motion vector within each set of sample positions; obtaining a refined motion vector based on the computed matching cost of each candidate motion vector; and obtaining prediction values for a current block based on the refined motion vector.

公开(公告)号：US20240364914A1

公开(公告)日：2024-10-31

申请号：US18655369

申请日：2024-05-06

Applicant: HUAWEI TECHNOLOGIES CO., LTD.

Inventor： Sriram SETHURAMAN ,  Jeeva Raj A. ,  Sagar KOTECHA

IPC: H04N19/513 ,  H04N19/523

CPC classification number: H04N19/513 ,  H04N19/523

Abstract: Given that decoder side motion vector refinement/derivation is a normative aspect of a coding system, the encoder will also have to perform the same error surface technique in order to not have any drift between the encoder's reconstruction and the decoder's reconstruction. Hence, all aspects of all embodiments are applicable to both encoding and decoding systems. In template matching, the refinement movement occurs only in the reference starting from the sub-pixel accurate center that is derived based on the explicitly signaled merge index or implicitly through cost evaluations. In bilateral matching (with or without averaged template), the refinements start in the reference lists L0 and L1 starting from the respective sub-pixel accurate centers that are derived based on the explicitly signaled merge index or implicitly through cost evaluations.

公开(公告)号：US20220368921A9

公开(公告)日：2022-11-17

申请号：US17249771

申请日：2021-03-12

Applicant: HUAWEI TECHNOLOGIES CO., LTD.

Inventor： Sriram SETHURAMAN ,  Jeeva Raj A ,  Sagar KOTECHA

IPC: H04N19/137 ,  H04N19/159 ,  H04N19/105 ,  H04N19/70 ,  H04N19/52 ,  H04N19/176

Abstract: A method for inter-prediction of a current image block in a current picture of a video is provided. The method includes determining whether a first temporal distance (such as TD0) is equal to a second temporal distance (such as TD1), wherein the first temporal distance is represented in terms of a difference between a picture order count value of the current picture and a picture order count value of a first reference image; and the second temporal distance is represented in terms of a difference between a picture order count value of a second reference image and the picture order count value of the current picture; and performing no motion vector refinement (DMVR) procedure when it is determined that the first temporal distance (TD0) is not equal to the second temporal distance (TD1). Thus the DMVR procedure is restricted to only the image block with equal-distance references.

公开(公告)号：US20220007051A1

公开(公告)日：2022-01-06

申请号：US17478184

申请日：2021-09-17

Applicant: HUAWEI TECHNOLOGIES CO., LTD.

Inventor： Sriram SETHURAMAN ,  Jeeva Raj A. ,  Sagar KOTECHA

IPC: H04N19/577 ,  H04N19/176 ,  H04N19/132 ,  H04N19/172

Abstract: In some embodiments, a video encoder or a video decoder obtains a pair of motion vectors for a current coding block of a video signal with respect to two reference frames. Predictions of the current block are generated using the pair of motion vectors from respective reference frames. The video encoder or video decoder further determine an optical flow for the current coding block based on samples values in the predictions. One component of the optical flow is determined based on the other component of the optical flow. Bi-predictive optical flow (BPOF) can be performed on the current coding block using the determined optical flow.

公开(公告)号：US20210392334A1

公开(公告)日：2021-12-16

申请号：US17407617

申请日：2021-08-20

Applicant: HUAWEI TECHNOLOGIES CO., LTD.

Inventor： Semih ESENLIK ,  Sriram SETHURAMAN ,  Jeeva Raj A ,  Sagar KOTECHA

IPC: H04N19/132 ,  H04N19/117 ,  H04N19/82 ,  H04N19/159 ,  H04N19/176

Abstract: It is provided a method of video coding implemented in a decoding device or an encoding device, the method comprising: obtaining initial motion vectors for a current block; obtaining first predictions for a sample value in the current block based on the initial motion vectors; calculating a first matching cost according to the first predictions; determining whether an optical flow refinement process should be performed or not, according to at least one preset condition, the at least one preset condition comprising a condition of whether the calculated first matching cost is equal to or larger than a threshold value; and performing an optical flow refinement process for obtaining a final inter prediction for the sample value in the current block, when it is determined that the optical flow refinement process should be performed.

公开(公告)号：US20220368888A9

公开(公告)日：2022-11-17

申请号：US17466129

申请日：2021-09-03

Applicant: HUAWEI TECHNOLOGIES CO., LTD.

Inventor： Sriram SETHURAMAN ,  Semih ESENLIK ,  Jeeva Raj A ,  Sagar KOTECHA

IPC: H04N19/105 ,  H04N19/132 ,  H04N19/137 ,  H04N19/159 ,  H04N19/46 ,  H04N19/176

Abstract: The present disclosure provides an inter prediction method, comprising the steps of obtaining an initial motion vector and a reference picture for bi-prediction; obtaining sets of candidate sample positions in the reference picture according to the initial motion vector and candidate motion vectors, wherein each candidate motion vector is derived by the initial motion vector and a respective motion vector offset, and wherein each set of candidate sample positions corresponds to each candidate motion vector; obtaining a respective set of sample positions from each set of candidate sample positions; computing a matching cost for each candidate motion vector within each set of sample positions; obtaining a refined motion vector based on the computed matching cost of each candidate motion vector; and obtaining prediction values for a current block based on the refined motion vector.