Method and apparatus for video-encoding/decoding using filter information prediction

This application is a divisional reissue of application Ser. No. 15/939,006, now abandoned, which is an application for reissue of U.S. Pat. No. 9,363,533.

The present invention relates to video processing, and more particularly, to video coding/decoding method and apparatus.

Recently, with the expansion of broadcasting services having high definition (HD) resolution in the country and around the world, many users have been accustomed to a high resolution and definition video, such that many organizations have conducted many attempts to develop next-generation video devices. In addition, the interest in HDTV and ultra high definition (UHD) having a resolution four times higher than that of HDTV have increased and thus, a compression technology for higher-resolution and higher-definition video have been required.

For the video compression, an inter prediction technology of predicting pixel values included in a current picture from a picture before and/or after the current picture, an intra prediction technology of predicting pixel values included in a current picture using pixel information in the current picture, an entropy coding technology of allocating a short code to symbols having a high appearance frequency and a long code to symbols having a low appearance frequency, a filtering technology of reducing distortion, error, blocking artifact occurring in the reconstructed picture, or the like, may be used.

An example of the video compression technology may include a technology providing a predetermined network bandwidth under a limited operation environment of hardware, without considering a flexible network environment. However, in order to compress video data applied to the network environment in which the bandwidth is frequently changed, a new compression technology is required. To this end, a scalable video coding/decoding method may be used.

In addition, in order to provide the three-dimensional videos, a multi-view video coding/decoding method may also be used. In the currently released three-dimensional video coding/decoding method, more than two-view videos are displayed on a spatially split display panel while simultaneously reproducing each video of an individual view. The views of videos simultaneously reproduced are separated by driving schemes such as a polarizing film, a lenticular sheet, a parallax barrier, or the like. Therefore, videos of different views are provided to two eyes of a person and the reproduced videos are recognized as three-dimensional videos.

The present invention provides scalable video coding method and apparatus capable of improving video compression performance while reducing transmitted information amount.

The present invention also provides scalable video decoding method and apparatus capable of improving video compression performance while reducing transmitted information amount.

The present invention also provides multi-view video coding method and apparatus capable of improving video compression performance while reducing transmitted information amount.

The present invention also provides multi-view video decoding method and apparatus capable of improving video compression performance while reducing transmitted information amount.

The present invention also provides filtering method and apparatus capable of improving video compression performance while reducing transmitted information amount.

The present invention also provides filter information prediction method and apparatus capable of improving video compression performance while reducing transmitted information amount.

In an aspect, there is provided a scalable video decoding method based on multi layers, including: generating second filter information including prediction values for first filter information by using at least one of information included in an object layer and information included in the other layer; and performing filtering on a video to be filtered by using the first filter information based on the second filter information, wherein the object layer is a layer including the video to be filtered, the other layer that is a layer other than the object layer is used to perform decoding at the object layer, the first filter information is information for filtering of the video to be filtered, and the second filter information is prediction filter information generated for filtering the video to be filtered.

The first filter information may be at least one of adaptive loop filter information, interpolation filter information, and deblocking filter information.

The scalable video decoding method may further include receiving a filter information prediction indicator from a coder, wherein the filter information prediction indicator may indicate at least one of information on whether prediction for any of the first filter information is performed, information on whether the prediction for the first filter information is performed using information of any layer, information on whether the first filter information is predicted from any filter information, and information on a method using the second filter information.

At the generating of the second filter information including the prediction values for the first filter information, the prediction for the first filter information may be performed using information included in a layer indicated by the filter information prediction indicator among the object layer and the other layer.

The scalable video decoding method may further include receiving difference information of the first filter information and the second filter information from a coder, wherein the performing of the video to be filtered using the first filter information based on the second filter information may include: generating the first filter information by summing up the second filter information and the difference information; and performing the filtering on the video to be filtered using the first filter information.

In another aspect, there is provided a filtering method for decoding scalable videos based on multi layers, including: generating second filter information including prediction values for first filter information by using at least one of information included in an object layer and information included in the other layer; and performing filtering on a video to be filtered by using the first filter information based on the second filter information, wherein the object layer is a layer including the video to be filtered, the other layer that is a layer other than the object layer is used to perform decoding at the object layer, the first filter information is information for filtering of the video to be filtered, and the second filter information is prediction filter information generated for filtering the video to be filtered.

The first filter information may be at least one of adaptive loop filter information, interpolation filter information, and deblocking filter information.

The filtering method may further include receiving a filter information prediction indicator from a coder, wherein the filter information prediction indicator indicates at least one of information on whether prediction for any of the first filter information is performed, information on whether the prediction for the first filter information is performed using information of any layer, information on whether the first filter information is predicted from any filter information, and information on a method using the second filter information.

At the generating of the second filter information including the prediction values for the first filter information, the prediction for the first filter information may be performed using information included in a layer indicated by the filter information prediction indicator among the object layer and the other layer.

The filtering method may further include receiving difference information of the first filter information and the second filter information from a coder, wherein the performing of the video to be filtered using the first filter information based on the second filter information may include: generating the first filter information by summing up the second filter information and the difference information; and performing the filtering on the video to be filtered using the first filter information.

In another aspect, there is provided a multi-view video decoding method based on videos captured at multi views, including: generating second filter information including prediction values for first filter information by using at least one of information included in an object view and information included in the other view; and performing filtering on a video to be filtered by using the first filter information based on the second filter information, wherein the object view is a view including the video to be filtered, the other view that is a view other than the object view is used to perform decoding at the object view, the first filter information is information for filtering of the video to be filtered, and the second filter information is prediction filter information generated for filtering the video to be filtered.

The first filter information may be at least one of adaptive loop filter information, interpolation filter information, and deblocking filter information.

The multi-view video decoding method may further include receiving a filter information prediction indicator from a coder, wherein the filter information prediction indicator indicates at least one of information on whether prediction for any of the first filter information may be performed, information on whether the prediction for the first filter information is performed using information of any layer, information on whether the first filter information is predicted from any filter information, and information on a method using the second filter information.

At the generating of the second filter information including the prediction values for the first filter information, the prediction for the first filter information may be performed using information included in a view indicated by the filter information prediction indicator among the object view and the other view.

The multi-view video decoding method may further include receiving difference information of the first filter information and the second filter information from a coder, wherein the performing of the video to be filtered using the first filter information based on the second filter information includes: generating the first filter information by summing up the second filter information and the difference information; and performing the filtering on the video to be filtered using the first filter information.

In another aspect, there is provided a filtering method for decoding multi-view videos based on videos captured at multi views, including: generating second filter information including prediction values for first filter information by using at least one of information included in an object view and information included in the other view; and performing filtering on a video to be filtered by using the first filter information based on the second filter information, wherein the object view is a view including the video to be filtered, the other view that is a view other than the object view is used to perform decoding at the object view, the first filter information is information for filtering of the video to be filtered, and the second filter information is prediction filter information generated for filtering the video to be filtered.

The first filter information may be at least one of adaptive loop filter information, interpolation filter information, and deblocking filter information.

The filtering method may further include receiving a filter information prediction indicator from a coder, wherein the filter information prediction indicator indicates at least one of information on whether prediction for any of the first filter information is performed, information on whether the prediction for the first filter information is performed using information of any layer, information on whether the first filter information is predicted from any filter information, and information on a method using the second filter information.

At the generating of the second filter information including the prediction values for the first filter information, the prediction for the first filter information may be performed using information included in a view indicated by the filter information prediction indicator among the object view and the other view.

The filtering method may further include receiving difference information of the first filter information and the second filter information from a coder, wherein the performing of the video to be filtered using the first filter information based on the second filter information includes: generating the first filter information by summing up the second filter information and the difference information; and performing the filtering on the video to be filtered using the first filter information.

As set forth above, the exemplary embodiments of the present invention can improve the video compression performance while reducing the transmitted information amount, by using the scalable video coding method.

In addition, the exemplary embodiments of the present invention can improve the video compression performance while reducing the transmitted information amount by using the scalable video decoding method.

Further, the exemplary embodiments of the present invention can improve the video compression performance while reducing the transmitted information amount by using the multi-view video coding method.

In addition, the exemplary embodiments of the present invention can improve the video compression performance while reducing the transmitted information amount by the multi-view video decoding method.

In addition, the exemplary embodiments of the present invention can improve the video compression performance while reducing the transmitted information amount by using the filtering method.

In addition, the exemplary embodiments of the present invention can improve the video compression performance while reducing the transmitted information amount by using the filtering prediction method.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. In describing exemplary embodiments of the present invention, well-known functions or constructions will not be described in detail since they may unnecessarily obscure the understanding of the present invention.

It will be understood that when an element is simply referred to as being ‘connected to’ or ‘coupled to’ another element without being ‘directly connected to’ or ‘directly coupled to’ another element in the present description, it may be ‘directly connected to’ or ‘directly coupled to’ another element or be connected to or coupled to another element, having the other element intervening therebetween. Further, in the present invention, “comprising” a specific configuration will be understood that additional configuration may also be included in the embodiments or the scope of the technical idea of the present invention.

Terms used in the specification, ‘first’, ‘second’, etc. can be used to describe various components, but the components are not to be construed as being limited to the terms. The terms are only used to differentiate one component from other components. For example, the ‘first’ component may be named the ‘second’ component without being departed from the scope of the present invention and the ‘second’ component may also be similarly named the ‘first’ component.

Furthermore, constitutional parts shown in the embodiments of the present invention are independently shown so as to represent characteristic functions different from each other. Thus, it does not mean that each constitutional part is constituted in a constitutional unit of separated hardware or software. In other words, each constitutional part includes each of enumerated constitutional parts for convenience. Thus, at least two constitutional parts of each constitutional part may be combined to form one constitutional part or one constitutional part may be divided into a plurality of constitutional parts to perform each function. The embodiment where each constitutional part is combined and the embodiment where one constitutional part is divided are also included in the scope of the present invention, if not departing from the essence of the present invention.

In addition, some of constituents may not be indispensable constituents performing essential functions of the present invention but be selective constituents improving only performance thereof. The present invention may be implemented by including only the indispensable constitutional parts for implementing the essence of the present invention except the constituents used in improving performance. The structure including only the indispensable constituents except the selective constituents used in improving only performance is also included in the scope of the present invention.

is a block diagram showing a configuration of a video coding apparatus according to an exemplary embodiment of the present invention. Referring to, a video coding apparatusincludes a motion predictor, a motion compensator, an intra predictor, a switch, a subtractor, a transformer, a quantizer, an entropy coder, a dequantizer, an inverse transformer, an adder, a filter unit, and a reference picture buffer. The reference picture buffermay be referred to as a decoded picture buffer. Hereinafter, the reference picture bufferhas the same meaning as a decoded picture buffer. In addition, the picture may have the same meaning as video according to a context or need.

The video coding apparatusmay perform coding on input videos to be coded with an intra mode or an inter mode and output bit streams. The intra prediction means intra-picture prediction and the inter prediction means inter-picture prediction. In the case of the intra mode, the switchis switched to intra and in the case of the inter mode, the switchis switched to inter mode. The video coding apparatusmay generate a prediction block for an input block of the input videos and then, code a difference between the input block and the prediction block.

In the case of the intra mode, the intra predictormay perform the spatial prediction using the pixel values of the previously coded blocks around the current block to generate the prediction block.

In the inter mode, the motion predictormay search a region optimally matched with the input block in the reference picture stored in the reference picture bufferduring the motion prediction process to obtain a motion vector. The motion compensatormay perform the motion compensation by using the motion vector and the reference picture stored in the reference picture bufferto generate the prediction block.

When the motion predictorand the motion compensatorin the inter mode perform the prediction to generate the prediction blocks, an interpolation filter may be used so as to predict pixel values in a sub-sample unit of a reconstructed video or a reconstructed block. The interpolation filter may be applied before or after the reconstructed picture or the reconstructed block is stored in the reference picture buffer. The interpolation filter may be based on a Wiener filter or a filter having a fixing filter coefficient.

When the interpolation filter is used, the pixel values in the block to be predicted may be predicted in a unit of an integer pixel or less to minimize distortion or difference between the video to be coded and the video to be previously reconstructed. Therefore, when the interpolation filter is used, video coding efficiency may be improved.

The subtractormay generate a residual block by the difference between the input block and the generated prediction block. The transformermay output transform coefficients by performing a transform on the residual block. Further, the quantizermay quantize the input transform coefficient according to quantization parameters to output quantized coefficients.