TECHNICAL FIELD

This document is related to video 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

The disclosed techniques may be used by video decoder or encoder embodiments for allowing a flexible signaling and use of motion vector precision for bi-predictive encoding in which up to two lists of reference frames are used by motion vectors. In one example aspect, different precisions may be allowed for different reference lists. The precision used for each reference frame may be content dependent or defined by an a priori set of rules.

In one example aspect, a method of processing a video bitstream includes determining a motion precision set based on coding information of a current block. A conversion between a video block and a coded representation of the video block is performed based on the motion precision set. The conversion corresponds to a reconstruction of the current block.

In another example aspect, a MVD precision of a current block from a motion precision set is determined based on a selected motion precision set and a signaled motion vector difference (MVD) precision index. A conversion between a video block and a coded representation of the video block using a MVD is performed based on the MVD precision. The MVD represents a difference between a predicted motion vector and an actual motion vector used during motion compensation processing.

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

In another example aspect, the above-described method may be implemented by a video encoder apparatus comprising a processor for decoding encoded video during video encoding process.

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.

