CROSS REFERENCE TO RELATED APPLICATIONS

This application is a U.S. National Stage Application of International Application No. PCT/KR2017/013728, filed on Nov. 28, 2017, which claims the benefit under 35 USC 119(a) and 365(b) of Korean Patent Application No. 10-2017-0160978, filed on Nov. 28, 2017, Korean Patent Application No. 10-2017-0073948, filed on Jun. 13, 2017, Korean Patent Application No. 10-2017-0021796, filed on Feb. 17, 2017, Korean Patent Application No. 10-2016-0159716, filed Nov. 28, 2016, in the Korean Intellectual Property Office, the entire disclosure of which is incorporated herein by reference for all purposes.

TECHNICAL FIELD

The following embodiments relate generally to a video decoding method and apparatus and a video encoding method and apparatus, and more particularly, to a method and apparatus for performing filtering in video encoding and decoding.

BACKGROUND ART

With the continuous development of the information and communication industries, broadcasting services supporting High-Definition (HD) resolution have been popularized all over the world. Through this popularization, a large number of users have become accustomed to high-resolution and high-definition images and/or videos.

To satisfy users' demand for high definition, many institutions have accelerated the development of next-generation imaging devices. Users' interest in UHD TVs, having resolution that is more than four times as high as that of Full HD (FHD) TVs, as well as High-Definition TVs (HDTV) and FHD TVs, has increased. As interest therein has increased, image encoding/decoding technology for images having higher resolution and higher definition is continually required.

An image encoding/decoding apparatus and method may use inter-prediction technology, intra-prediction technology, entropy-coding technology, etc. so as to perform encoding/decoding on a high-resolution and high-definition image. Inter-prediction technology may be technology for predicting the value of a pixel included in a current picture using temporally previous pictures and/or temporally subsequent pictures. Intra-prediction technology may be technology for predicting the value of a pixel included in a current picture using information about pixels in the current picture. Entropy-coding technology may be technology for assigning short code words to frequently occurring symbols and assigning long code words to rarely occurring symbols.

In order to improve the efficiency and accuracy of intra prediction and/or inter prediction, various types of filtering technologies have been developed. Such filtering technologies may be technologies for applying a filter to the target to be filtered, and then adjusting the value of the target.

DISCLOSURE

Technical Problem

An embodiment is intended to provide an encoding apparatus and method and a decoding apparatus and method, which perform filtering on a reference sample.

An embodiment is intended to provide an encoding apparatus and method and a decoding apparatus and method, which use an interpolation filter.

Technical Solution

In accordance with an aspect, there is provided an encoding apparatus, including a processing unit for performing filtering on a target, generating filtering information that indicates whether filtering has been performed on the target, and generating a bitstream including the filtering information; and a communication unit for transmitting the bitstream to a decoding apparatus.

In accordance with another aspect, there is provided a decoding apparatus, including a communication unit for receiving a bitstream; and a processing unit for acquiring filtering information from the bitstream, determining, based on the filtering information, whether to perform filtering on a target, and then performing filtering on the target.

In accordance with a further aspect, there is provided a decoding method, including determining whether to perform filtering on a target; and performing filtering on the target if it is determined that filtering is to be performed on the target.

The decoding method may further include receiving a bitstream; and acquiring filtering information from the bitstream,

Whether to perform filtering on the target may be determined based on the filtering information.

The decoding method may further include deriving filtering information.

Whether to perform filtering on the target may be determined based on the filtering information.

A filter for performing filtering may be a strong filter or a weak filter.

The strong filter may include a linear interpolation filter.

The target may be a reference sample of a reconstructed neighboring block adjacent to a target block.

The reference sample may include multiple reference samples.

The filtering may be selectively performed on a sample that satisfies a predefined condition, among the multiple reference samples.

When a linear relationship is present among the multiple reference samples, a strong filter may be used for the filtering.

When a linear relationship is not present among the multiple reference samples, a weak filter may be used for the filtering.

Whether to perform filtering may be determined based on one or more of a size of a target block, a prediction mode of the target block, and a type of the target block.

A target block may be a coding unit.

The filtering may be determined for each coding unit.

Whether to perform the filtering on a reference sample of the coding unit may be determined based on information about neighboring blocks adjacent to the coding unit.

A filter for performing the filtering may be determined based on a coding parameter related to intra prediction.

A filter for performing the filtering may be determined based on a prediction mode of intra prediction.

A filter for performing the filtering may be an interpolation filter.

The interpolation filter may be used for integer pixels, and thus sub-pixels may be generated.

The interpolation filter may be used for interpolation of a sub-pixel reference sample.

The interpolation filter may be used for motion compensation.

The interpolation filter may include multiple interpolation filters.

One or more of the multiple interpolation filters may be selected based on an attribute of a block or a coding parameter related to the block.

The interpolation filter may be selected based on a correlation between a target block and a reference block of the target block.

Advantageous Effects

There are provided an encoding apparatus and method and a decoding apparatus and method, which perform filtering on a reference sample.

There are provided an encoding apparatus and method and a decoding apparatus and method, which use an interpolation filter.

