TECHNICAL FIELD

The present invention relates to image processing technology.

BACKGROUND ART

Recently, as demands for high-resolution and high-quality video have increased, high-efficiency video compression technology for next-generation video services is necessary.

In the video compression technology, quantization coefficient encoding and decoding technologies mean technology of generating a bitstream through entropy encoding technology performed on a signal subjected to transform and quantization with respect to a difference signal between an original signal and a prediction signal or technology of reconstructing the generated bitstream into the difference signal through entropy decoding technology.

DISCLOSURE

Technical Problem

An object of the present invention is to provide a method and apparatus for enhancing encoding efficiency in association with video compression technology.

Another object of the present invention is to provide a method and apparatus in which a decoder derives information on a motion vector and this enables video encoding/decoding to be performed effectively in such a manner that a video encoder/decoder for high-resolution images such as full-high-definition (FHD) images and ultra-high-definition (UHD) images effectively transmits motion information.

Another object of an embodiment of the present invention is to provide a method and apparatus for performing global motion compensation on an extensive region in an image.

Another object of an embodiment of the present invention is to provide a method and apparatus for generating a reference signal to effectively perform intra prediction.

Another object of an embodiment of the present invention is to provide a method and apparatus using a curve intra prediction technique in the video compression technology.

However, it is to be understood that technical problems to be solved by the present disclosure are not limited to the aforementioned technical problems and other technical problems may be present.

Technical Solution

In order to accomplish the above objects, according to an embodiment of the present invention, a video decoding apparatus and method include: a quantization coefficient group information obtainment module obtaining information on a quantization coefficient group for inverse quantization; a quantization coefficient group entropy decoding module obtaining quantization coefficients through entropy decoding on the quantization coefficient group; an inverse quantization module obtaining transform coefficients through inverse quantization on the obtained quantization coefficients; and an inverse transform module obtaining difference signals through an inverse transform process on the obtained transform coefficients.

In order to accomplish the above objects, according to an embodiment of the present invention, a video decoding apparatus and method include: a variably-sized quantization coefficient group usage extraction module extracting information on whether a variably-sized quantization coefficient group is used with respect to a current decoding bitstream, from the bitstream; a quantization coefficient group partition information decoding module obtaining partition information on the quantization coefficient group for inverse quantization in a current decoding unit when the extracted information on whether the variably-sized quantization coefficient group is used indicates that the variably-sized quantization coefficient group is used; and a quantization coefficient entropy decoding module performing quantization coefficient entropy decoding.

In order to accomplish the above objects, according to an embodiment of the present invention, a video decoding apparatus and method include: a quantization coefficient group partition flag extraction module extracting a quantization coefficient group partition flag with respect to partition from a bitstream on the basis of a size of a current decoding unit; a quantization coefficient group size determination module determining a size of the quantization coefficient group in the current decoding unit when the extracted quantization coefficient group partition flag indicates non-partition; a sub quantization coefficient group partition module partitioning the current decoding unit into multiple sub quantization coefficient groups when the extracted quantization coefficient group partition flag indicates partition; and a quantization coefficient group entropy decoding module performing quantization coefficient group entropy decoding.

In order to accomplish the above objects, according to an embodiment of the present invention, a video decoding apparatus and method include: a variably-sized quantization coefficient group usage extraction module extracting information on whether a variably-sized quantization coefficient group is used with respect to a current decoding bitstream, from the bitstream; a quantization coefficient group partition method determination module determining a method of partitioning the variably-sized quantization coefficient group when the extracted information on whether the variably-sized quantization coefficient group is used indicates that the variably-sized quantization coefficient group is used; and a quantization coefficient group size information obtainment module obtaining information on a size of the quantization coefficient group for inverse quantization in a current decoding unit according to the determined method of partitioning the variably-sized quantization coefficient group.

In order to accomplish the above objects, according to an embodiment of the present invention, a video decoding apparatus and method include: a quantization coefficient group partition number information extraction module extracting quantization coefficient group partition number information with respect to partition from a bitstream on the basis of a size of a current decoding unit; and a quantization coefficient group partition module partitioning a quantization coefficient group using partition information defined on the basis of a method of partitioning a variably-sized quantization coefficient group, the size of the current decoding unit, and the quantization coefficient group partition number information.

In order to accomplish the above objects, according to an embodiment of the present invention, a video decoding apparatus and method include: a variably-sized quantization coefficient group usage information extraction module extracting information on whether a variably-sized quantization coefficient group is used with respect to a current decoding bitstream, from the bitstream; a quantization coefficient group partition information obtainment module obtaining partition information of the quantization coefficient group for inverse quantization in a current decoding unit when the extracted information on whether the variably-sized quantization coefficient group is used indicates that the variably-sized quantization coefficient group is used; and an entropy decoding scanning order obtainment module obtaining an entropy decoding scanning order of the quantization coefficient group on the basis of partition information on the quantization coefficient group for inverse quantization.

In order to accomplish the above objects, according to an embodiment of the present invention, the video decoding apparatus and method include a motion information derivation unit or step, and a decoder may derive motion information without information on a motion vector directly received from an encoder.

As technical means for achieving the above objects, according to an embodiment of the present invention, an image decoding apparatus and method include: obtaining information for global motion compensation from a bitstream; determining a global motion compensation region using the information for global motion compensation; and performing global motion compensation on the determined global motion compensation region.

As technical means for achieving the above objects, according to an embodiment of the present invention, an image decoding apparatus and method include: extracting a flag indicating whether global motion compensation is used from a bitstream; determining a global motion compensation region from the bitstream when the extracted flag indicates use of global motion compensation; and extracting information for performing motion compensation on each determined global motion region.

As technical means for achieving the above objects, according to an embodiment of the present invention, an image decoding apparatus and method include: extracting a flag indicating whether global motion compensation is used from a bitstream; and performing motion compensation on a per-coding block basis when the extracted flag indicates non-use of global motion compensation.

As technical means for achieving the above objects, according to an embodiment of the present invention, an image decoding apparatus and method include: determining a region subjected to global motion compensation using motion compensation region determination information obtained from a bitstream; and performing motion compensation on each determined region subjected to motion compensation.

As technical means for achieving the above objects, according to an embodiment of the present invention, an image decoding apparatus and method include: performing global motion compensation on each global motion compensation region using performance information for each motion compensation region obtained from a bitstream.

As technical means for achieving the above technical objects, according to an embodiment of the present invention, in performing intra prediction, an image decoding method and apparatus may generate a signal on an unreconstructed region using a neighboring reconstruction signal referenced for intra prediction such that effective intra prediction is performed. Also, a range to be referenced for intra prediction in a reconstructed signal is expanded compared with a conventional range such that many more reconstruction pixels are referenced. Accordingly, intra prediction performance is enhanced.

As technical means for achieving the above objects, according to an embodiment of the present invention, an image decoding apparatus and method include: extracting information for generating a prediction signal from a bitstream; performing reference sample padding using the extracted information; generating a prediction sample by performing curve intra prediction using the extracted information; and performing filtering on the generated prediction sample.

As technical means for achieving the above objects, according to an embodiment of the present invention, an image decoding apparatus and method include: obtaining information for generating a prediction signal from a bitstream; and extracting information on curve intra prediction from the bitstream when the extracted intra prediction mode information indicates curve intra prediction.

As technical means for achieving the above objects, according to an embodiment of the present invention, an image decoding apparatus and method include: determining whether to perform reference sample padding using information on curve intra prediction obtained from a bitstream and information on whether a reference sample of a neighboring block is present; and performing reference sample padding.

As technical means for achieving the above objects, according to an embodiment of the present invention, an image decoding apparatus and method include generating a prediction sample using information on curve intra prediction obtained from a bitstream.

As technical means for achieving the above objects, according to an embodiment of the present invention, an image decoding apparatus and method include performing filtering using a variation in a neighboring reference sample when with respect to a left prediction sample column and a top prediction sample row of a generated prediction block, a region containing the sample column is subjected to horizontal direction prediction or vertical direction prediction.

Advantageous Effects

The present invention is intended to provide a method and apparatus that use a quantization coefficient group that is in variable size depending on the characteristics of a signal and use an encoding and decoding order corresponding thereto, whereby quantization coefficient encoding efficiency is enhanced.

According to the embodiment of the present invention, the variably-sized quantization coefficient group and selective coefficient encoding and decoding order are used to increase the number of coefficients excluded from encoding, whereby performance of quantization coefficient encoding is enhanced.

Also, according to the embodiment of the present invention, the quantization coefficient group varies in size and shape so that an energy concentration effect by transform and quantization and a high frequency component removal effect are obtained, whereby performance of coefficient encoding is enhanced.

According to the above-described technical solution of the present invention, in the decoder, a motion information derivation unit or step enables video decoding without direct transmission of a motion vector, whereby video encoding/decoding efficiency is enhanced.

The present invention is intended to propose a method and apparatus for performing global motion compensation on an extensive region in a motion compensation process used in a conventional video compression technology so as to enhance encoding efficiency.

According to an embodiment of the present invention, motion compensation is performed on an extensive region at once, and information on a global motion compensation region is effectively transmitted to the decoder, thereby enhancing encoding performance.

According to the above-described technical solution of the present invention, the decoder generates the intra prediction signal and expands a reference range so that intra prediction performance is enhanced, whereby overall performance of video compression performance is enhanced.

The present invention is intended to propose a method and apparatus for performing curve intra prediction in an intra prediction process used in the conventional video compression technology so as to enhance encoding/decoding efficiency.

According to the above-described technical solution of the present invention, curve intra prediction enhances intra prediction efficiency in the encoder/decoder so that video compression performance is enhanced.

