TECHNICAL FIELD

This patent document relates to video coding techniques, devices and systems.

BACKGROUND

In spite of the advances in video compression, digital video still 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

Devices, systems and methods related to digital video coding, and specifically, to sample refinement and filtering methods for video coding are described. The described methods may be applied to both the existing video coding standards, such as High Efficiency Video Coding (HEVC), and future video coding standards, such as Versatile Video Coding (VVC) or codecs.

In one representative aspect, the disclosed technology may be used to provide a method for video processing. This method includes applying, for a conversion between a current block of a video and a bitstream representation of the video, a clipping operation to a weighted average of differences between a pixel and neighboring pixels of the pixel in the current block. The method also includes performing the conversion based on an output of the clipping operation.

In another representative aspect, the disclosed technology may be used to provide a method for video processing. This method includes configuring, for a conversion between a current block of a video and a bitstream representation of the video, a filtering process based on a set of neighboring pixels of the current block. The method also includes performing the conversion based on and output of the filtering process.

In another representative aspect, the disclosed technology may be used to provide a method for video processing. This method includes modifying, for a conversion between a block of a video and a bitstream representation of the video, a refinement value for a prediction sample in the block by applying a clipping operation to refinement value. The refinement value is derived based on a gradient value of an optical flow coding process. An output of the clipping operation is within a range. The method also includes refining the prediction sample based on the modified refinement value and performing the conversion based on the refined prediction sample.

In another representative aspect, the disclosed technology may be used to provide a method for video processing. This method includes modifying, for a conversion between a block of a video and a bitstream representation of the video, a gradient value in an optical flow coding process. The method also includes performing a subsequence prediction operation based on the modified gradient value for the conversion.

In another representative aspect, the disclosed technology may be used to provide a method for video processing. This method includes configuring, for a current video block, a one-dimensional filtering process, and reconstructing, based on the one-dimensional filtering process, the current video block from a corresponding bitstream representation.

In yet another representative aspect, the above-described method is embodied in the form of processor-executable code and stored in a computer-readable program medium.

In yet another representative aspect, a device that is configured or operable to perform the above-described method is disclosed. The device may include a processor that is programmed to implement this method.

In yet another representative aspect, a video decoder apparatus may implement a method as described herein.

The above and other aspects and features of the disclosed technology are described in greater detail in the drawings, the description and the claims.

