Motion compensation method and device using bidirectional optical flow
AssigneeSK Telecom Co., Ltd.
InventorsJeong-yeon LIM, Hyo Song KIM, Hyeong-duck KIM, Se-hoon SON, Jae-seob SHIN, Gyeong-taek LEE, Sun-young LEE
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Abstract
Disclosed herein is a method for adaptive bidirectional optical flow estimation for inter-screen prediction compensation during video encoding. The method aims to reduce complexity and/or cost of bidirectional optical flow (BIO) at a pixel level or a subblock level.
Claims11
An inter prediction apparatus for predicting a target block using a bi-directional optical flow in a video encoding, the apparatus comprising one or more processor configured to:
- generate a first motion vector for a first reference picture and a second motion vector for a second reference picture;
- derive a variable from sample value differences between samples in the first reference picture which are determined based on the first motion vector and samples in the second reference picture which are determined based on the second motion vector, wherein the variable is SAD (Sum of Absolute Differences) or SSE (Sum of Squared Errors) and is used for determining whether to apply the bi-directional optical flow;
- and
- generate a prediction block of the target block from the first and second reference pictures, by selectively either performing or skipping the bi-directional optical flow depending on the variable,
- wherein the bi-directional optical flow is performed by the unit of samples in the target block or by the unit of sub-blocks partitioned from the target block.
An inter prediction method for predicting a target block using a bi-directional optical flow in a video decoding, the method comprising:
- generating a first motion vector for a first reference picture and a second motion vector for a second reference picture;
- deriving a variable from sample value differences between samples in the first reference picture which are determined based on the first motion vector and samples in the second reference picture which are determined based on the second motion vector, wherein the variable is SAD (Sum of Absolute Differences) or SSE (Sum of Squared Errors) and is used for determining whether to apply the bi-directional optical flow;
- and
- generating a prediction block of the target block from the first and second reference pictures, by selectively either performing or skipping the bi-directional optical flow depending on the variable,
- wherein the bi-directional optical flow is performed by the unit of samples in the target block or by the unit of sub-blocks partitioned from the target block.
A non-transitory recording medium storing a bitstream generated by an inter prediction method of predicting a target block using a bi-directional optical flow, the method comprising:
- generating a first motion vector for a first reference picture and a second motion vector for a second reference picture;
- deriving a variable from sample value differences between samples in the first reference picture which are determined based on the first motion vector and samples in the second reference picture which are determined based on the second motion vector, wherein the variable is SAD (Sum of Absolute Differences) or SSE (Sum of Squared Errors) and is used for determining whether to apply the bi-directional optical flow;
- and
- generating a prediction block of the target block from the first and second reference pictures, by selectively either performing or skipping the bi-directional optical flow depending on the variable,
- wherein the bi-directional optical flow is performed by the unit of samples in the target block or by the unit of sub-blocks partitioned from the target block.
Dependencies are inferred from the claim text.