TECHNICAL FIELD

This document is related to video and image coding and decoding technologies.

BACKGROUND

Digital video accounts for the largest bandwidth use on the internet and other digital communication networks. As the number of connected user devices capable of receiving and displaying video increases, it is expected that the bandwidth demand for digital video usage will continue to grow.

SUMMARY

In one example aspect, a method of processing video is disclosed. The method includes performing a conversion between a current block of visual media data and a corresponding coded representation of the visual media data, wherein the conversion of the current block includes determining whether a use of one or both of a bi-directional optical flow (BIO) technique or a decoder-side motion vector refinement (DMVR) technique to the current block is enabled or disabled, and wherein the determining the use of the BIO technique or the DMVR technique is based on a cost criterion associated with the current block.

In another example aspect, a method of processing video is disclosed. The method includes performing a conversion between a current block of visual media data and a corresponding coded representation of the visual media data, wherein the conversion of the current block includes determining whether a use of a decoder-side motion vector refinement (DMVR) technique to the current block is enabled or disabled, and wherein the DMVR technique includes refining motion information of the current block based on a cost criterion other than a mean removed sum of absolute differences (MRSAD) cost criterion.

In another example aspect, a method of processing video is disclosed. The method includes performing a conversion between a current block of visual media data and a corresponding coded representation of the visual media data, wherein the conversion of the current block includes determining whether a use of one or both of a bi-directional optical flow (BIO) technique or a decoder-side motion vector refinement (DMVR) technique to the current block is enabled or disabled, and wherein the determining the use of the BIO technique or the DMVR technique is based on computing that a mean value difference of a pair of reference blocks associated with the current block exceeds a threshold value.

In another example aspect, a method of processing video is disclosed. The method includes modifying a first reference block to generate a first modified reference block, and a second reference block to generate a second modified reference block, wherein both the first reference block and the second reference block are associated with a current block of visual media data; determining differences between the first modified reference block and the second modified reference block, the differences including one or more of: a sum of absolute transformed differences (SATD), a mean removed sum of absolute transformed differences (MRSATD), a sum of squares error (SSE), a mean removed sum of squares error (MRSSE), a mean value difference, or gradient values; and performing a conversion between the current block of visual media data and a corresponding coded representation of the visual media data, wherein the conversion includes a use of the differences between the first modified reference block and the second modified reference block generated from respectively modifying the first reference block and the second reference block.

In another example aspect, a method of processing video is disclosed. The method includes determining a temporal gradient or a modified temporal gradient using reference pictures associated with a current block of visual media data, the temporal gradient or the modified temporal gradient indicative of differences between the reference pictures; and performing a conversion between the current block of visual media data and a corresponding coded representation of the visual media data, wherein the conversion includes a use of a bi-directional optical flow (BIO) technique based in part on the temporal gradient or the modified temporal gradient.

In another example aspect, a method of processing video is disclosed. The method includes determining a first temporal gradient using reference pictures associated with a first video block or a sub-block thereof; determining a second temporal gradient using reference pictures associated with a second video block or a sub-block thereof; performing a modification of the first temporal gradient and a modification of the second temporal gradient to generate a modified first temporal gradient and a modified second temporal gradient, wherein the modification of the first temporal gradient associated with the first video block is different from the modification of the second temporal gradient associated with the second video block; and performing a conversion of the first video block and the second video block to their corresponding coded representation.

In another example aspect, a method of processing video is disclosed. The method includes modifying one or both of a first inter reference block and a second inter reference block associated with a current block; determining, based on using the one or both modified first inter reference block and/or the modified second inter reference block, a spatial gradient associated with the current block in accordance with applying a bi-directional optical (BIO) flow technique; and performing a conversion between the current block and a corresponding coded representation, wherein the conversion includes a use of the spatial gradient associated with the current block.

In another example aspect, a method of processing video is disclosed. The method includes performing a determination, by a processor, that a flag signaled at a block level indicates, at least in part, that one or both of a decoder-side motion vector refinement (DMVR) technique or a bi-directional optical flow (BIO) technique is to be enabled for a current block; and performing a conversion between the current block and a corresponding coded representation, wherein the coded representation includes the flag indicating whether the one or both of the DMVR technique and/or the BIO technique is enabled.

In another example aspect, a method of processing video is disclosed. The method includes performing a determination, by a processor that a decoder-side motion vector refinement (DMVR) technique is to be enabled for a current block, wherein the determination is based exclusively on a height of the current block; and performing a conversion between the current block and a corresponding coded representation.

In another example aspect, a method of processing video is disclosed. The method includes performing a conversion between a current block of visual media data and a corresponding coded representation of visual media data, wherein the conversion includes a use of rules associated with one or both of a decoder-side motion vector refinement (DMVR) technique or a bi-directional optical flow (BIO) technique on the current block, wherein the rules associated with the DMVR technique are consistent with application to the BIO technique; and wherein determining whether the use of the one or both of the BIO technique or the DMVR technique on the current block is enabled or disabled is based on applying the rules.

In another example aspect, the above-described methods may be implemented by a video decoder apparatus that comprises a processor.

In another example aspect, the above-described methods may be implemented by a video encoder apparatus that comprises a processor.

In yet another example aspect, these methods may be embodied in the form of processor-executable instructions and stored on a computer-readable program medium.

These, and other, aspects are further described in the present document.

