US 12,003,703 B2 · Complexity reduction and bit-width control for bi-directional optical flow

Abstract

Systems and methods are described for reducing the complexity of using bi-directional optical flow (BIO) in video coding. In some embodiments, bit-width reduction steps are introduced in the BIO motion refinement process to reduce the maximum bit-width used for BIO calculations. In some embodiments, simplified interpolation filters are used to generate predicted samples in an extended region around a current coding unit. In some embodiments, different interpolation filters are used for vertical versus horizontal interpolation. In some embodiments, BIO is disabled for coding units with small heights and/or for coding units that are predicted using a sub-block level inter prediction technique, such as advanced temporal motion vector prediction (ATMVP) or affine prediction.

Claims20

Dependent claims

A video encoding method comprising:

obtaining a first prediction signal array from a first reference picture and a second prediction signal array from a second reference picture;
performing a right bit shift on the first prediction signal array to obtain a bit-shifted first prediction signal array and on the second prediction signal array to obtain a bit-shifted second prediction signal array;
obtaining a signal-difference parameter array based on a difference between the bit-shifted first prediction signal array and the bit-shifted second prediction signal array;
obtaining at least a first-component motion refinement based at least in part on the signal-difference parameter array;
and
generating a prediction of a current block in a video with bi-directional optical flow using at least the first-component motion refinement.

3 more elements

A video encoder comprising one or more processors configured to perform:

obtaining a first prediction signal array from a first reference picture and a second prediction signal array from a second reference picture;
performing a right bit shift on the first prediction signal array to obtain a bit-shifted first prediction signal array and on the second prediction signal array to obtain a bit-shifted second prediction signal array;
obtaining a signal-difference parameter array based on a difference between the bit-shifted first prediction signal array and the bit-shifted second prediction signal array;
obtaining at least a first-component motion refinement based at least in part on the signal-difference parameter array;
and
generating a prediction of a current block in a video with bi-directional optical flow using at least the first-component motion refinement.

3 more elements

A video decoding method comprising:

obtaining a first prediction signal array from a first reference picture and a second prediction signal array from a second reference picture;
performing a right bit shift on the first prediction signal array to obtain a bit-shifted first prediction signal array and on the second prediction signal array to obtain a bit-shifted second prediction signal array;
obtaining a signal-difference parameter array based on a difference between the bit-shifted first prediction signal array and the bit-shifted second prediction signal array;
obtaining at least a first-component motion refinement based at least in part on the signal-difference parameter array;
and
generating a prediction of a current block in a video with bi-directional optical flow using at least the first-component motion refinement.

3 more elements

A video decoder comprising one or more processors configured to perform:

obtaining a first prediction signal array from a first reference picture and a second prediction signal array from a second reference picture;
performing a right bit shift on the first prediction signal array to obtain a bit-shifted first prediction signal array and on the second prediction signal array to obtain a bit-shifted second prediction signal array;
obtaining a signal-difference parameter array based on a difference between the bit-shifted first prediction signal array and the bit-shifted second prediction signal array;
obtaining at least a first-component motion refinement based at least in part on the signal-difference parameter array;
and
generating a prediction of a current block in a video with bi-directional optical flow using at least the first-component motion refinement.

3 more elements

Dependencies are inferred from the claim text.

Facts

Application

17/962,918Filed 10 Oct 2022 · continuation

Priority

21 Sep 2018

Published

US 2023/0053233 A116 Feb 2023

Granted

4 Jun 2024

Term ends

Not estimatedThe source records don’t support an estimate.

Classification10 codes

H04N 19/105
Selection of coding mode or of prediction mode: selection of the reference unit for prediction within a chosen coding or prediction mode, e.g.…
H04N 19/132
Characterised by the element, parameter or selection affected or controlled by the adaptive coding: sampling, masking or truncation of coding…
H04N 19/146
Characterised by the element, parameter or criterion affecting or controlling the adaptive coding: data rate or code amount at the encoder output
H04N 19/159
Assigned coding mode, i.e. the coding mode being predefined or preselected to be further used for selection of another element or parameter:…

Family

Application62/734,763Us provisional application · filed 21 Sep 2018

Application62/738,655Us provisional application · filed 28 Sep 2018

Application62/789,331Us provisional application · filed 7 Jan 2019

PCT/US2019/051560Parent of this continuation · filed 17 Sep 2019

US 2023/0053233 A1Pre-grant publication · published 16 Feb 2023

Application17/276,448Parent of this continuation

US 11,470,308 B2Parent of this continuation

US 2022/0038679 A1Published application

US 12,003,703 B2This patent

From the US filing history. Foreign family members aren’t listed.

Complexity reduction and bit-width control for bi-directional optical flow

Life of this patent

Complexity reduction and bit-width control for bi-directional optical flow

Life of this patent

Abstract

Claims20