KR102325977B1 - Video decoding method and apparatus using the same - Google Patents

Abstract

An image decoding method according to an embodiment of the present invention comprises the steps of: decoding information on a first hierarchical picture that can be referenced by a second hierarchical picture to be decoded; generating information of a reference picture between base layers by using the information of the first layer picture; generating enhanced inter-layer reference picture information by using the first layer picture information, the base inter-layer reference picture information, and the second layer picture information; Generating a reference picture list in which inter prediction of the second layer picture is used using the information of the base inter-layer reference picture, the information of the enhanced inter-layer reference picture, and the information of the second layer picture. can

Description

Video decoding method and apparatus using the same

The present invention relates to encoding and decoding processing of an image, and more particularly, to a method and apparatus for encoding and decoding an image supporting a plurality of layers in a bitstream.

Recently, as broadcasting services having high definition (HD) resolution are expanding not only in Korea but also worldwide, many users are getting used to high-resolution and high-definition images, and accordingly, many organizations are spurring the development of next-generation imaging devices. In addition, as interest in UHD (Ultra High Definition) having a resolution four times higher than that of HDTV increases along with HDTV, compression technology for higher resolution and high-definition images is required.

For image compression, inter prediction technology that predicts pixel values included in the current picture from temporally previous and/or later pictures, predicting pixel values included in the current picture using pixel information in the current picture An intra prediction technique, an entropy encoding technique in which a short code is assigned to a symbol having a high frequency of occurrence and a long code is assigned to a symbol having a low frequency of occurrence, may be used.

In video compression technology, there is a technology that provides a constant network bandwidth under a limited operating environment of hardware without considering a flexible network environment. However, a new compression technique is required to compress image data applied to a network environment in which bandwidth is frequently changed, and for this purpose, a scalable video encoding/decoding method may be used.

The present invention provides an image decoding method capable of reducing the complexity of an encoder and decoder through motion compensation in integer pixel units when generating an improved inter-layer reference image, and an apparatus using the same.

In addition, a method for decoding an image capable of increasing decoding efficiency by omitting transmission of weight information by obtaining and applying a weight based on an encoding parameter, and an apparatus using the same are provided.

Accordingly, a method for decoding an image capable of increasing the precision of lower-layer information that can be used as a prediction signal in encoding and decoding an image of an upper layer during encoding and decoding of an image based on a multi-layer structure, and an apparatus using the same are provided.

According to an embodiment of the present invention, a method for decoding an image supporting a plurality of layers includes decoding information on a first layer picture that can be referenced by a second layer picture to be decoded; generating information of a reference picture between base layers by using the information of the first layer picture; generating enhanced inter-layer reference picture information by using the first layer picture information, the base inter-layer reference picture information, and the second layer picture information; Generating a reference picture list in which inter prediction of the second layer picture is used using the information of the base inter-layer reference picture, the information of the enhanced inter-layer reference picture, and the information of the second layer picture. can

The generating of the information of the reference picture between the base layers may include: generating a first inter-layer reference picture obtained by mapping a first layer picture size to a picture size of the second layer; and generating a second inter-layer reference picture in which the decoded temporal reference pictures of the first layer picture are mapped to the size of the temporal reference picture of the second layer picture.

The step of generating the enhanced inter-layer reference picture information includes a reference picture of the second layer picture and a motion vector of a block of the first layer picture corresponding to a target block to be decoded of the second layer picture. deriving a first reference block on which motion compensation is performed on the target block; deriving a second reference block obtained by performing motion compensation on the inter-layer corresponding block of the first inter-layer reference picture corresponding to the target block using the second inter-layer reference picture and the motion vector; generating a difference block corresponding to a difference between the first reference block and the second reference block; and adding the inter-layer corresponding block to the residual block.

The method may further include applying a weight to the residual block.

Further comprising the step of determining whether a reference picture index of the temporal reference picture of the first hierarchical picture has a preset value, if the reference picture index has the preset value, the target block and the inter-layer corresponding block Motion compensation using a motion interpolation filter may be performed.

Motion compensation performed to derive the first reference block and the second reference block may be performed in units of integer pixels.

The generating of the enhanced inter-layer reference picture information may include: generating a difference picture between a reference picture of the second layer picture and a second base inter-layer reference picture; Inter-layer correspondence of the reference picture between the first base layers corresponding to the target block by using the motion vector of the block of the first hierarchical picture corresponding to the target block to be decoded of the differential picture and the second hierarchical picture deriving a third reference block on which motion compensation is performed on the block; and summing the third reference block and the inter-layer corresponding block.

The method may further include applying a weight to the third reference block.

The method further comprises the step of determining whether a reference picture index of a temporal reference picture of the first layer picture has a predetermined value, and when the reference picture index has the predetermined value, with respect to the target block and the layer corresponding block Motion compensation using a motion interpolation filter may be performed.

Motion compensation performed to derive the third reference block may be performed in units of integer pixels.

An apparatus for decoding an image supporting a plurality of layers according to another embodiment of the present invention includes: an entropy decoding unit for decoding information on a first hierarchical picture that can be referenced by a second hierarchical picture to be decoded; Inter-layer information is generated using the information of the first hierarchical picture, and information of the base inter-layer reference picture is improved using the information of the first hierarchical picture, the information of the base inter-layer reference picture, and the information of the second hierarchical picture. A reference picture in which inter-picture prediction of the second layer picture is generated by generating information of a reference picture, and using the information of the base inter-layer reference picture, the information of the enhanced inter-layer reference picture, and the information of the second layer picture It may include a prediction unit that generates a list.

According to an embodiment of the present invention, a method for decoding an image capable of reducing the complexity of an encoder and decoder through motion compensation in units of integer pixels when generating an improved inter-layer reference image, and an apparatus using the same are provided.

In addition, a method for decoding an image capable of increasing decoding efficiency by omitting transmission of weight information by obtaining and applying a weight based on an encoding parameter, and an apparatus using the same are provided.

Accordingly, a method for decoding an image capable of increasing the precision of lower layer information that can be used as a prediction signal in encoding and decoding an image of an upper layer during encoding and decoding of an image based on a multi-layer structure, and an apparatus using the same are provided.

1 is a block diagram illustrating a configuration of an image encoding apparatus according to an embodiment.
2 is a block diagram illustrating a configuration of an image decoding apparatus according to an embodiment.
3 is a conceptual diagram schematically illustrating an embodiment of a scalable video coding structure using a plurality of layers to which the present invention can be applied.
4 is a control flowchart illustrating a video decoding method according to the present invention.
5 is a diagram for explaining an improved inter-layer reference picture according to an embodiment of the present invention.
6 is a schematic diagram illustrating an improved generation of an inter-layer reference picture according to another embodiment of the present invention.
7 is a schematic diagram for explaining improved generation of an inter-layer reference picture according to another embodiment of the present invention.

EMBODIMENT OF THE INVENTION Hereinafter, embodiment of this invention is described concretely with reference to drawings. In describing the embodiments of the present specification, if it is determined that a detailed description of a related known configuration or function may obscure the gist of the present specification, the detailed description thereof will be omitted.

When it is said that a component is “connected” or “connected” to another component, it may be directly connected or connected to the other component, but it is understood that other components may exist in between. it should be In addition, the content described as “including” a specific configuration in the present invention does not exclude configurations other than the corresponding configuration, and means that additional configurations may be included in the practice of the present invention or the scope of the technical spirit of the present invention.

Terms such as first, second, etc. may be used to describe various elements, but the elements should not be limited by the terms. The above terms are used only for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, a first component may be referred to as a second component, and similarly, a second component may also be referred to as a first component.

In addition, the components shown in the embodiment of the present invention are shown independently to represent different characteristic functions, and it does not mean that each component is composed of separate hardware or a single software component. That is, each component is listed as each component for convenience of description, and at least two components of each component are combined to form one component, or one component can be divided into a plurality of components to perform a function, and each Integrated embodiments and separate embodiments of components are also included in the scope of the present invention without departing from the essence of the present invention.

In addition, some of the components are not essential components for performing essential functions in the present invention, but may be optional components for merely improving performance. The present invention can be implemented by including only essential components to implement the essence of the present invention, except for components used for performance improvement, and a structure including only essential components excluding optional components used for performance improvement Also included in the scope of the present invention.

1 is a block diagram illustrating a configuration of an image encoding apparatus according to an embodiment. A scalable video encoding/decoding method or apparatus may be implemented by extension of a general image encoding/decoding method or apparatus that does not provide scalability, and the block diagram of FIG. 1 is scalable. An embodiment of an image encoding apparatus that can be the basis of a video encoding apparatus is shown.

Referring to FIG. 1 , the image encoding apparatus 100 includes a motion prediction unit 111 , a motion compensation unit 112 , an intra prediction unit 120 , a switch 115 , a subtractor 125 , and a transform unit 130 . , a quantizer 140 , an entropy encoder 150 , an inverse quantizer 160 , an inverse transform unit 170 , an adder 175 , a filter unit 180 , and a reference image buffer 190 .

The image encoding apparatus 100 may perform encoding on an input image in an intra mode or an inter mode and output a bit stream. Intra prediction refers to intra prediction, and inter prediction refers to inter prediction. In the intra mode, the switch 115 is switched to intra, and in the inter mode, the switch 115 is switched to inter. The image encoding apparatus 100 may generate a prediction block for an input block of an input image, and then encode a difference between the input block and the prediction block.

In the intra mode, the intra prediction unit 120 may generate a prediction block by performing spatial prediction using pixel values of an already coded block around the current block.

In the inter mode, the motion predictor 111 may obtain a motion vector by finding a region that best matches the input block in the reference image stored in the reference image buffer 190 during the motion prediction process. The motion compensator 112 may generate a prediction block by performing motion compensation using a motion vector and a reference image stored in the reference image buffer 190 .

The subtractor 125 may generate a residual block by the difference between the input block and the generated prediction block. The transform unit 130 may perform transform on the residual block to output a transform coefficient. In addition, the quantization unit 140 may quantize the input transform coefficient according to the quantization parameter to output a quantized coefficient.

The entropy encoding unit 150 entropy-encodes a symbol according to a probability distribution based on the values calculated by the quantization unit 140 or an encoding parameter value calculated during the encoding process to generate a bit stream. can be printed out. The entropy encoding method is a method of receiving symbols having various values, removing statistical redundancy, and expressing them as a decodable binary number sequence.

Here, the symbol means a syntax element to be encoded/decoded, a coding parameter, and a value of a residual signal. Encoding parameters are parameters necessary for encoding and decoding, and may include information that is encoded in the encoder and transmitted to the decoder, such as syntax elements, as well as information that can be inferred during the encoding or decoding process. means necessary information. Coding parameters include, for example, intra/inter prediction modes, motion/motion vectors, reference image indexes, coding block patterns, residual signal presence, transform coefficients, quantized transform coefficients, quantization parameters, block size, block partition information, etc. It may include statistics. In addition, the residual signal may mean a difference between the original signal and the predicted signal, and a signal in which the difference between the original signal and the predicted signal is transformed or a signal in which the difference between the original signal and the predicted signal is transformed and quantized. may mean The residual signal may be referred to as a residual block in block units.

When entropy encoding is applied, a small number of bits are allocated to a symbol having a high probability of occurrence and a large number of bits are allocated to a symbol having a low probability of occurrence to express the symbol, so that the size of the bit string for the symbols to be encoded is increased. can be reduced. Accordingly, compression performance of image encoding may be improved through entropy encoding.

For entropy encoding, an encoding method such as exponential golomb, Context-Adaptive Variable Length Coding (CAVLC), or Context-Adaptive Binary Arithmetic Coding (CABAC) may be used. For example, the entropy encoding unit 150 may store a table for performing entropy encoding, such as a variable length coding (VLC) table, and the entropy encoding unit 150 may store the stored variable length encoding. Entropy encoding can be performed using a (VLC) table. In addition, the entropy encoder 150 derives a binarization method of a target symbol and a probability model of a target symbol/bin, and then performs entropy encoding using the derived binarization method or probability model. You may.

The quantized coefficient may be inverse quantized by the inverse quantizer 160 and inversely transformed by the inverse transform unit 170 . The inverse-quantized and inverse-transformed coefficients may be added to the prediction block through the adder 175 and a reconstructed block may be generated.

The reconstructed block passes through the filter unit 180, and the filter unit 180 applies at least one of a deblocking filter, a sample adaptive offset (SAO), and an adaptive loop filter (ALF) to the reconstructed block or the reconstructed picture. can do. The reconstructed block passing through the filter unit 180 may be stored in the reference image buffer 190 .

2 is a block diagram illustrating a configuration of an image decoding apparatus according to an embodiment. As described above with reference to FIG. 1 , the scalable video encoding/decoding method or apparatus may be implemented by extension of a general image encoding/decoding method or apparatus that does not provide scalability, and the block diagram of FIG. 2 shows scalable video decoding An embodiment of an image decoding apparatus that can be the basis of the apparatus is shown.

Referring to FIG. 2 , the image decoding apparatus 200 includes an entropy decoding unit 210 , an inverse quantization unit 220 , an inverse transform unit 230 , an intra prediction unit 240 , a motion compensator 250 , and a filter unit. 260 and a reference image buffer 270 .

The image decoding apparatus 200 may receive a bitstream output from the encoder, perform decoding in an intra mode or an inter mode, and output a reconstructed image, that is, a reconstructed image. In the case of the intra mode, the switch may be switched to the intra mode, and in the case of the inter mode, the switch may be switched to the inter mode. The image decoding apparatus 200 may generate a reconstructed block, that is, a reconstructed block by obtaining a reconstructed residual block from the received bitstream, generating a prediction block, and adding the reconstructed residual block and the prediction block.

The entropy decoding unit 210 may entropy-decode the input bitstream according to a probability distribution to generate symbols including symbols in the form of quantized coefficients. The entropy decoding method is a method of generating each symbol by receiving a binary string as an input. The entropy decoding method is similar to the entropy encoding method described above.

The quantized coefficient is inverse quantized by the inverse quantization unit 220 and inverse transformed by the inverse transformation unit 230 , and as a result of inverse quantization/inverse transformation of the quantized coefficient, a reconstructed residual block may be generated.

In the intra mode, the intra prediction unit 240 may generate a prediction block by performing spatial prediction using pixel values of an already encoded block around the current block. In the inter mode, the motion compensator 250 may generate a prediction block by performing motion compensation using a motion vector and a reference image stored in the reference image buffer 270 .

The reconstructed residual block and the prediction block are added through the adder 255 , and the added block passes through the filter unit 260 . The filter unit 260 may apply at least one of a deblocking filter, SAO, and ALF to a reconstructed block or a reconstructed picture. The filter unit 260 outputs a reconstructed image, that is, a reconstructed image. The restored image may be stored in the reference image buffer 270 and used for inter prediction.

The entropy decoding unit 210 , the inverse quantization unit 220 , the inverse transform unit 230 , the intra prediction unit 240 , the motion compensator 250 , and the filter unit 260 included in the image decoding apparatus 200 . and components directly related to image decoding among the reference image buffer 270 , for example, the entropy decoding unit 210 , the inverse quantization unit 220 , the inverse transform unit 230 , the intra prediction unit 240 , and motion compensation. The unit 250 and the filter unit 260 may be distinguished from other components and expressed as a decoder or a decoder.

Also, the image decoding apparatus 200 may further include a parsing unit (not shown) that parses information related to the encoded image included in the bitstream. The parsing unit may include the entropy decoding unit 210 or may be included in the entropy decoding unit 210 . This parsing unit may also be implemented as one component of the decoding unit.

3 is a conceptual diagram schematically illustrating an embodiment of a scalable video coding structure using a plurality of layers to which the present invention can be applied. In FIG. 3 , a group of pictures (GOP) indicates a picture group, that is, a group of pictures.

In order to transmit image data, a transmission medium is required, and its performance is different for each transmission medium according to various network environments. A scalable video coding method may be provided for application to such various transmission media or network environments.

The scalable video coding method is a coding method that improves encoding/decoding performance by removing inter-layer redundancy by utilizing texture information, motion information, residual signals, etc. between layers. The scalable video coding method may provide various scalability in terms of spatial, temporal, and picture quality according to ambient conditions such as a transmission bit rate, a transmission error rate, and a system resource.

Scalable video coding may be performed using a structure of multiple layers so as to provide a bitstream applicable to various network situations. For example, the scalable video coding structure may include a base layer that compresses and processes image data using a general image encoding method, and compresses the image data using both encoding information of the base layer and a general image encoding method. It may include an enhancement layer to process.

Here, a layer is an image and bit classified based on spatial (eg, image size), temporal (eg, encoding order, image output order, frame rate), image quality, complexity, etc. It means a set of streams (bitstream). In addition, a base layer may mean a lower layer or a reference layer, and an enhancement layer may mean an upper layer. Also, a plurality of layers may have dependencies on each other.

Referring to FIG. 3 , for example, the base layer may be defined as SD (standard definition), a frame rate of 15 Hz, and a bit rate of 1 Mbps, and the first enhancement layer is HD (high definition), a frame rate of 30 Hz, and a bit rate of 3.9 Mbps. may be defined, and the second enhancement layer may be defined as 4K-UHE (ultra high definition), a frame rate of 60 Hz, and a bit rate of 27.2 Mbps. The format, frame rate, bit rate, etc. are an example and may be differently determined as needed. Also, the number of layers to be used is not limited to the present embodiment and may be determined differently according to circumstances.

For example, if the transmission bandwidth is 4 Mbps, the frame rate of the first enhancement layer HD may be reduced to transmit at 15 Hz or less. The scalable video coding method may provide temporal, spatial, and picture quality scalability by the method described above in the embodiment of FIG. 3 .

Scalable video coding has the same meaning as scalable video coding in terms of encoding and scalable video decoding in terms of decoding.

The present invention relates to an en-/de-coding process of an image including a plurality of layers or views, wherein the plurality of layers or views are first, second, third, It can be expressed as an n-th layer or a viewpoint. In the following description, a picture in which the first layer and the second layer exist is described as an example, and the same method can be applied to layers or views above that. Also, the first layer may be expressed as a base layer, and the second layer may be expressed as an upper layer. Also, the first layer may be expressed as a reference layer, and the second layer may be expressed as an enhancement layer.

The picture/block of the first layer corresponding to the picture/block of the second layer may be changed according to the size of the picture/block of the second layer. That is, when the size of the picture/block of the first layer is smaller than the picture/block of the second layer, scaling may be performed using a method such as up-sampling or re-sampling.

Also, the picture of the first layer may be added to the reference picture list of the second layer and used for image encoding/decoding of the second layer. In this case, the second layer may perform prediction and encoding/decoding by using the first layer image in the reference picture list like normal inter prediction.

The size of the block for encoding/decoding may be an NxN-shaped square such as 4x4, 8x8, 16x16, 32x32, 64x64, or an NxM-shaped rectangle such as 4x8, 16x8, 8x32, etc., and the unit of the block is a Coding Block (CB). ), a prediction block (PB), and a transform block (TB), and each may have a different size.

Hereinafter, a prediction block of a block (hereinafter referred to as a current block or a target block) that is a target for encoding and decoding of a higher layer among scalable video, that is, an image encoding and decoding method using a multi-layer structure, that is, a prediction signal is generated Let's see how to do it. The content (method or apparatus) of the following invention can be equally applied to an encoder and a decoder in general.

Meanwhile, the prediction signal of the target block may be generated through inter prediction.

In the inter prediction, at least one of a picture before or after a picture of the current picture may be used as a reference picture, and prediction of the current block may be performed based on the reference picture. An image used for prediction of the current block is referred to as a reference picture or a reference frame.

The region in the reference picture may be indicated using a reference picture index refIdx indicating the reference picture, a motion vector, and the like.

Inter prediction may generate a prediction block for the current block by selecting a reference picture and a reference block corresponding to the current block in the reference picture.

In inter prediction, the encoder and the decoder may derive motion information of the current block and then perform inter prediction and/or motion compensation based on the derived motion information. At this time, the encoder and the decoder obtain the motion information of the collocated block corresponding to the current block in the reconstructed neighboring block and/or the collocated picture that has already been reconstructed. By using it, encoding/decoding efficiency can be improved.

Here, the reconstructed neighboring block is a block in the reconstructed current picture that has already been encoded and/or decoded, and may include a block adjacent to the current block and/or a block located at an outer corner of the current block. In addition, the encoder and the decoder may determine a predetermined relative position based on a block existing at a position spatially corresponding to the current block in the collocated picture, and the determined relative position (a position spatially corresponding to the current block) The collocated block can be derived based on the position inside and/or outside the block existing in . Here, as an example, the collocated picture may correspond to one of the reference pictures included in the reference picture list.

In the inter prediction, a prediction block may be generated such that a residual signal with a current block is minimized and a motion vector size is also minimized.

Meanwhile, the method of deriving motion information may vary depending on the prediction mode of the current block. Prediction modes applied for inter prediction may include Advanced Motion Vector Predictor (AMVP), merge, and the like.

For example, when Advanced Motion Vector Predictor (AMVP) is applied, the encoder and decoder may generate a predictive motion vector candidate list by using a motion vector of a reconstructed neighboring block and/or a motion vector of a collocated block. That is, the motion vector of the reconstructed neighboring block and/or the motion vector of the collocated block may be used as a prediction motion vector candidate. The encoder may transmit a predicted motion vector index indicating an optimal predicted motion vector selected from among the predicted motion vector candidates included in the list to the decoder. In this case, the decoder may select the predicted motion vector of the current block from among the predicted motion vector candidates included in the predicted motion vector candidate list by using the predicted motion vector index.

The encoder may obtain a motion vector difference (MVD) between the motion vector of the current block and the predicted motion vector, encode it, and transmit it to the decoder. In this case, the decoder may decode the received motion vector difference, and may derive the motion vector of the current block through the sum of the decoded motion vector difference and the predicted motion vector.

The encoder may also transmit a reference picture index indicating the reference picture to the decoder.

The decoder may predict the motion vector of the current block using motion information of the neighboring block, and may derive the motion vector of the current block using the residual received from the encoder.

The decoder may receive information about which neighboring block motion information is used, a difference between a motion vector of the current block and a predicted motion vector, and a reference picture index encoder indicating a reference picture.

The decoder may generate a prediction block for the current block based on the derived motion vector and reference picture index information received from the encoder.

As another example, when merge is applied, the encoder and the decoder may generate a merge candidate list by using motion information of a reconstructed neighboring block and/or motion information of a collocated block. That is, when motion information of the reconstructed neighboring block and/or collocated block exists, the encoder and the decoder may use it as a merge candidate for the current block.

The encoder may select a merge candidate capable of providing optimal encoding efficiency from among merge candidates included in the merge candidate list as motion information for the current block. In this case, the merge index indicating the selected merge candidate may be included in the bitstream and transmitted to the decoder. The decoder may select one of the merge candidates included in the merge candidate list by using the transmitted merge index, and may determine the selected merge candidate as motion information of the current block. Accordingly, when the merge mode is applied, the motion information of the reconstructed neighboring block and/or the collocated block may be used as the motion information of the current block as it is. The decoder may reconstruct the current block by adding the prediction block and the residual transmitted from the encoder.

In the aforementioned AMVP and merge modes, in order to derive the motion information of the current block, motion information of a reconstructed neighboring block and/or motion information of a collocated block may be used.

In the case of the skip mode, which is one of the other modes used for inter prediction, information on neighboring blocks may be used for the current block as it is. Accordingly, in the skip mode, the encoder does not transmit syntax information such as residuals to the decoder other than information indicating which block to use as the motion information of the current block.

The encoder and the decoder may generate a prediction block of the current block by performing motion compensation on the current block based on the derived motion information. Here, the prediction block may mean a motion-compensated block generated as a result of performing motion compensation on the current block. Also, a plurality of motion-compensated blocks may constitute one motion-compensated image.

The decoder may check a skip flag, a merge flag, etc. received from the encoder for motion information necessary for inter prediction of the current block, for example, a motion vector, a reference picture index, and the like, and derive it accordingly.

A processing unit in which prediction is performed and a processing unit in which a prediction method and specific content are determined may be different from each other. For example, a prediction mode may be determined in a PU unit and prediction may be performed in a TU unit, or a prediction mode may be determined in a PU unit and intra prediction may be performed in a TU unit.

For convenience of description, terms for various pictures used in the present invention are summarized as follows.

The current part of the second layer and the decoding target picture may be expressed as an enhancement picture (EP), and the picture of the first layer corresponding to the current part and the decoding target picture of the second layer may be expressed as a base picture (BP). The first layer is not limited to the base layer and may include a reference layer referenced by a layer including a secondary and a decoding target picture.

When the inter-layer reference picture obtained by re-sampling the picture of the first layer can be expressed as an inter-layer picture (ILP), and the size of the picture between the picture layers of the first layer and the second layer is the same , ILP may be the same as the BP picture.

An enhanced inter-layer reference picture generated using the picture information of the first layer and the picture information of the second layer may be expressed as an Enhanced Inter-layer Picture (EILP).

The temporal reference reconstructed picture of the current secondary and decoding target picture of the second layer may be represented by EP', and the reconstructed picture of the first layer corresponding to the temporal reference reconstructed picture of the second layer may be represented by BP'. In the present specification, a temporal reference picture may mean a temporal reference picture used for inter prediction, and may refer to a reference picture belonging to the same layer as distinguished from an inter-layer reference picture.

Similar to ILP, when an inter-layer reference picture obtained by up-sampling a BP' picture is expressed as ILP', if the size of the inter-picture picture of the first layer and the second layer is the same, ILP' is the same as the BP' picture can do it

In an image supporting multi-layers, as a prediction signal of a target block of an upper layer, there is a method of using a reconstructed image of a lower layer, ie, a reference layer, to which the target block can be referred, in addition to the above-described inter prediction method.

4 is a control flowchart illustrating a video decoding method according to the present invention. More specifically, FIG. 4 illustrates a method of encoding and decoding a multilayer image using picture information of the first layer when performing the process of copying and decoding a picture of the second layer in the process of encoding and decoding a multilayer image. represents Accordingly, the description of FIG. 4 may be applied to both decoding and encoding methods of an image. Hereinafter, for convenience of explanation, the decoding process will be described as a reference.

First, the decoder decodes picture information of the first layer referenced by the picture of the second layer (S410).

The decoder may decode and use the encoded information of the first layer picture corresponding to the decoding object block of the second layer as reference information for predicting the object block.

The reference information may include a decoded first layer picture sample value or motion information.

The motion information of the first layer includes a motion vector value, a reference picture index, a prediction direction indicator, a reference picture POC (Picture Order Count), a prediction mode, a reference picture list, a merge flag, a merge index, and a picture type of the reference picture (short -term) reference picture, long-term reference picture) information, and the like.

The decoded motion information of the first layer may be compressed and stored to have the same motion information in units of NxN (eg, 16x16).

When the picture information of the first layer is generated, the decoder may generate information on the base inter-layer reference picture (ILP) by using the decoded picture information of the first layer ( S420 ).

The base inter-layer reference picture is a picture obtained by mapping the picture size of the first layer to the picture size of the second layer and the decoded temporal reference picture of the first layer picture corresponding to the picture of the second layer. It may include a picture mapped to the size of the temporal reference picture of .

When the size of the picture between the layers is different, up-sampling may be performed on the sample values of the first layer picture in order to map the decoded picture size of the first layer to the picture size of the second layer. .

For example, when the picture size of the decoded first layer is 960x540 and the picture size of the second layer is 1920x1080, upsampling is performed on the size of the decoded picture of the first layer to 1920x1080, which is the picture size of the second layer. can do. The upsampled picture may be used as a reference picture between the base layers.

On the other hand, when the sizes of inter-layer pictures are the same, the decoded picture of the first layer may be used as a base inter-layer reference picture.

According to another embodiment, when the sizes of inter-layer pictures are the same, a picture to which a filter is applied to the decoded first layer picture may be used as a base inter-layer reference picture.

For example, a picture to which a filter having a filter coefficient of [-1, 3, 12, 3 -1] is applied to the decoded first layer picture may be used as a base inter-layer reference picture.

Alternatively, when the sizes of inter-layer pictures are different, the decoder may apply a filter to a base inter-layer reference picture in which up-sampling is performed on sample values of the first layer picture.

According to another embodiment, when the sizes of inter-layer pictures are different, the motion information of the decoded first layer picture may be mapped to the size of the second layer picture and used as motion information of the reference picture between the base layers.

For example, the size of the reference picture between the base layers is divided into units of NxN, and motion information corresponding to a position in the first hierarchical picture corresponding to a specific coordinate value in the divided NxN block is transferred to the block in the reference picture between the base layers. information can be mapped. In this case, the motion information may be mapped by reflecting the horizontal and vertical size ratio of the picture between layers.

On the other hand, when the sizes of inter-layer pictures are the same, motion information in the decoded first layer picture may be used as motion information of the base inter-layer reference picture.

When the decoded picture information of the first layer and the reference picture information between the base layers are generated, the decoder uses the decoded picture information of the first layer, the reference picture information between the base layers and the decoded picture information of the second layer. Inter-reference picture (EILP) information may be generated (S430). In the following embodiment, for convenience of description, it is assumed that the ratio of the horizontal and vertical sizes of the pictures between the layers is twice each.

In order to generate an improved inter-layer reference picture, the decoded picture information of the first layer and the decoded picture information of the second layer may be used in addition to the base inter-layer reference picture generated in step S420.

5 is a diagram for explaining an improved inter-layer reference picture according to an embodiment of the present invention.

Referring to FIG. 5 , a plurality of pictures A, B, and C may form a reference picture group EP′ for inter prediction of the second layer picture EP. That is, the reference pictures A, B, and C decoded for inter prediction of the second layer picture EP may be stored in a memory such as the DPB, and these reference pictures A, B, and C are It may be included in the reference picture list.

The decoded temporal reference pictures (A', B', C') of the first hierarchical picture (BP) corresponding to the target picture (EP) also refer to the reference picture group (BP') for the first hierarchical picture (BP). can be formed

The base inter-layer reference pictures (A”, B”, C”) from which the decoded temporal reference pictures (BP') of the first layer picture (BP) are up-sampled are the base inter-layer reference picture group (ILP') can form.

The current part of the second layer, the enhanced inter-layer reference picture (EILP) for the picture to be decoded (EP) includes the decoded temporal reference pictures (EP') of the current part and the picture to be decoded (EP) in the second layer, Base inter-layer reference pictures (ILP) generated by up-sampling the decoded temporal reference pictures BP' and temporal reference pictures BP' of the first layer picture BP corresponding to the target picture EP. ') can be used to create

6 is a schematic diagram illustrating an improved generation of an inter-layer reference picture according to another embodiment of the present invention.

As shown in FIG. 6 , an enhanced inter-layer reference picture (EILP) is generated for prediction of the second layer part, the decoding target picture part (EP), and the decoding target block (①).

To this end, motion information (motion vector, reference picture index) of the first layer picture (BP) corresponding to the second layer target picture (EP), the current part of the second layer, and the base layer corresponding to the decoding target picture (EP) An inter-reference picture (ILP) may be used.

The ratio of the first layer picture BP and the temporal reference picture BP′ of the first layer picture to the horizontal and vertical sizes of the base inter-layer reference pictures ILP and ILP′ may be doubled, respectively.

The target block of the second layer target picture (EP), for example, the block of the first layer picture (BP) corresponding to the position of the NxN block (①) is ③, and the base layer corresponding to the position of the NxN block (①) The block of the inter reference picture (ILP) is ②. The target block (①) and the block ② of the reference picture (ILP) between the base layer are blocks existing in the same position. Block ② may be expressed as an inter-layer corresponding block with respect to target block ①, and block ③ may be expressed as a corresponding block with respect to target block ①.

In the temporal reference picture BP' of the first hierarchical picture BP, it may be assumed that the reference block on which the motion compensation for the block ③ is performed is ⑥, and the motion vector for the motion compensation is ⑦ MV.

In the temporal reference picture (EP') of the second layer picture (EP), the reference block on which the motion compensation for the target block (①) is performed is ④, and the temporal reference picture (BP') of the first layer picture (BP) is In the base inter-layer reference picture (ILP') generated by up-sampling, the reference block on which motion compensation is performed on the block ② of the base inter-layer reference picture (ILP') is ⑤. The blocks ④ and ⑤ on which the motion compensation has been performed as described above may be used when generating a prediction signal for the NxN block (②).

As shown in FIG. 6, the motion vector used for motion compensation for the target block (①) and motion compensation for the block ② of the base inter-layer reference picture (ILP') is the ratio of the horizontal and vertical size of the inter-layer picture. It is a vector (⑧ Scaled MV) obtained by scaling the motion vector (⑦) of the position of the first hierarchical block (③) in consideration.

In this embodiment, since the ratio of the first hierarchical picture (BP) and the temporal reference picture (BP') of the first hierarchical picture to the horizontal and vertical sizes of the base inter-layer reference pictures (ILP, ILP') is doubled, the second A vector in which the motion vector (⑦) at the position of the 1-layer block (③) is doubled may be used for motion compensation of the NxN block (②).

The decoder uses the scaled motion vector to obtain the sample value of the reference block (④) obtained through motion compensation on the temporal reference picture (EP') and the base inter-layer reference picture (ILP') through motion compensation. A difference block ⑨ is generated by finding a difference value between the sample values of the reference block ⑤.

The difference block (⑨) is added to the sample value of the NxN block (②) in the base inter-layer reference picture (ILP), and the new block (⑩) generated in this way may be used as a new sample value of the NxN block (②). That is, block ⑩ may be used as a prediction block for reconstructing the second layer picture (EP). The enhanced inter-layer reference picture EILP made of the new prediction block ⑩ may be included in the reference picture list used for inter prediction of the second layer picture EP.

According to an embodiment of the present invention, the decoder may apply a weight to the differential block (⑨) and then add it to the sample value of the NxN block (②).

The weight may be applied in units of pictures, slices, blocks, etc., and may be inferred by coding parameters (eg, motion vectors and reference picture indexes). In addition, after calculating the weight in the encoder, information on the determined weight value may be encoded and transmitted to the decoder.

For example, when the reference picture index of block ③ of the first hierarchical picture BP is “0”, the weight may be set to “1”, and when the reference picture index is “1”, 0.5 may be applied.

As another example, when the reference picture index of block ③ is “0”, the weight “1” may be applied, and when the reference picture index is “1”, the weight “0” may be applied.

In another embodiment, the weight may be set in consideration of the reference picture list of block ③, that is, the prediction direction. When the reference picture direction of block ③ is list 0 (LIST 0), the weight may be set to “1”, and when the reference picture direction is the list 1 (LIST 1), the weight “0.5” may be applied.

Different values may be applied to the weight according to a luminance (Luma) component and a chroma (chroma) component.

In summary, as shown in FIG. 6 , the decoder up-samples the first layer picture (BP) corresponding to the target picture (EP) of the second layer, an NxN block (②) in the base inter-layer reference picture (ILP), and the decoding A signal obtained by adding the difference signal between the reference block (④) of the target block (①) and the reference block (⑤) of the NxN block (②) can be used as a new sample value of the NxN block (②).

7 is a schematic diagram for explaining improved generation of an inter-layer reference picture according to another embodiment of the present invention. Also in the present embodiment, the ratio of the horizontal and vertical sizes of the inter-layer picture may be doubled, respectively.

According to the present embodiment, the decoder generates an inter-layer reference picture ( A prediction signal for the NxN block (②) can be generated using the differential picture (DP) between the ILP'.

To this end, motion information (motion vector, reference picture index) of the first layer picture (BP) corresponding to the second layer target picture (EP), the current part of the second layer, and the base layer corresponding to the decoding target picture (EP) An inter-reference picture (ILP) may be used.

In the temporal reference picture BP' of the first hierarchical picture BP, it may be assumed that the reference block on which the motion compensation for block ③ is performed is ④, and the motion vector for motion compensation is ⑤ MV.

The decoder generates a differential picture (DP) by subtracting the temporal reference picture (EP') of the current secondary and decoding target picture and the inter-layer reference picture (ILP') obtained by up-sampling the temporal reference picture from the first layer picture. The decoder may use the differential picture DP by adding a predetermined offset (eg, 128).

The decoder may perform motion compensation on the generated differential picture DP by using motion information on the position of the block ③ in the first hierarchical picture BP, that is, a scaled motion vector ⑥ Scaled MV.

In this embodiment, since the ratio of the first hierarchical picture (BP) and the temporal reference picture (BP') of the first hierarchical picture to the horizontal and vertical sizes of the base inter-layer reference pictures (ILP, ILP') is doubled, the block A vector obtained by multiplying the motion vector (⑤) of (③) by 2 can be used for motion compensation of the NxN block (②).

The decoder can add the sample value of the reference block (⑦) obtained through motion compensation of the NxN block (②) with the difference picture (DP) and the sample value of the NxN block (②), and the generated new block (⑧) ) can be used as a new sample value of the NxN block (②). The enhanced inter-layer reference picture EILP composed of the new block ⑧ may be included in the reference picture list used for inter prediction of the second layer picture EP.

When the difference picture DP is generated, if an offset value is added, the decoder may subtract the same offset value from the sample value of the reference block ⑦, and then add it with the sample value of the NxN block ②.

Also, the decoder may apply a weight to the sample value of the reference block ⑦ and then add it to the NxN block sample value.

The weight may be applied in units of pictures, slices, blocks, etc., and may be inferred by coding parameters (eg, motion vectors and reference picture indexes). In addition, after calculating the weight in the encoder, information on the determined weight value may be encoded and transmitted to the decoder.

For example, when the reference picture index of block ③ of the first hierarchical picture BP is “0”, the weight may be set to “1”, and when the reference picture index is “1”, 0.5 may be applied.

As another example, when the reference picture index of block ③ is “0”, the weight “1” may be applied, and when the reference picture index is “1”, the weight “0” may be applied.

In another embodiment, the weight may be set in consideration of the reference picture list of block ③, that is, the prediction direction. When the reference picture direction of block ③ is list 0 (LIST 0), the weight may be set to “1”, and when the reference picture direction is the list 1 (LIST 1), the weight “0.5” may be applied.

Different values may be applied to the weight according to a luminance (Luma) component and a chroma (chroma) component.

In summary, as shown in FIG. 7, the decoder up-samples the first layer picture (BP) corresponding to the target picture (EP) of the second layer with respect to the NxN block (②) in the base inter-layer reference picture (ILP), A block (⑧) to which the reference block (⑦) of the differential picture (DP) is added may be used as a new sample value of the NxN block (②).

Meanwhile, according to another embodiment of the present invention, the temporal reference picture (EP') of the second layer, the base inter-layer reference picture (ILP') obtained by up-sampling the first layer picture, or the temporal reference picture of the second layer ( A motion interpolation filter may be used when motion compensation is performed on the NxN block (②) with respect to the differential picture (DP) between the EP′) and the inter-base layer reference picture (ILP′).

For example, the decoder may generate a prediction signal having sub-pixel precision by using a motion interpolation filter, that is, an 8-tap DCT-IF filter for a luminance component and a 4-tap DCT-IF filter for a chrominance component.

Alternatively, the decoder may generate a prediction signal having sub-pixel precision by using the same bi-linear filter for the luminance component and the chrominance component.

For example, in order to reduce the complexity of motion compensation, the prediction signal may be generated to have integer pixel precision by omitting the sub-pixel motion compensation process.

In order to omit the sub-pixel motion compensation process, when the mapped motion vector of the NxN block (②) is MV0, the motion vector can be adjusted as follows.

In the case of the luminance component, the corrected motion vector MV0' can be obtained through an operation as in Equation 1 below.

<Formula 1>

MV0’ = (MV0 + R) & 0xFFFFFFFC,

In this case, if (MV0 % 4) < 2, R=0, if (MV0 % 4 ) >= 2, R=4 may be applied.

As another example, Equation 2 below may be applied.

<Formula 2>

MV0’ = (MV0 + R) & 0xFFFFFFFC,

In this case, if (MV0 % 4) <= 2, R=0, if (MV0 % 4) > 2, R=4 may be applied.

As another example, 0 or 4 can always be applied to R.

On the other hand, in the case of the chrominance component, the corrected motion vector MV0' can be obtained through an operation as in Equation 3 below.

<Equation 3>

MV0’ = (MV0 + R) & 0xFFFFFFF8,

In this case, if (MV0 % 8) < 4, R=0, if (MV0 % 8) >= 4, R=8 may be applied.

As another example, Equation 4 below may be applied to the motion vector MV0' of the chrominance component.

<Formula 4>

MV0’ = (MV0 + R) & 0xFFFFFFF8,

In this case, when (MV0 % 8) <= 4, R=0 may be applied, and when (MV0 % 8) > 4, R=8 may be applied.

As another example, always R can be 0 or 8.

According to another embodiment of the present invention, the base inter-layer reference picture obtained by up-sampling the temporal reference picture (EP') of the second layer and the first layer picture according to the embodiment described based on FIGS. 5 to 7 . In order to reduce complexity when motion compensation is performed on a differential picture (DP) between (ILP') or a temporal reference picture (EP') of the second layer and a base inter-layer reference picture (ILP'), a specific reference picture index Motion compensation can be performed only on NxN blocks having only values. That is, the decoder performs motion compensation only on the NxN block having only a specific reference picture index value, and converts the prediction value generated according to the motion compensation (that is, the reference block in FIG. 6 ⑨ the reference block ⑦ in FIG. 7) to the NxN block (②) ) can be added to

For example, only when the reference picture index value of the first layer block ③ corresponding to the NxN block ② of FIG. 6 is '0', the temporal reference picture (EP') of the second layer, the first layer image After motion compensation is performed on the NXN block (②) for the base inter-layer reference picture (ILP') up-sampled by ) can be added to the sample value of

As another example, only when the reference picture index value of the first layer block ③ corresponding to the NxN block ② of FIG. 7 is '0', the temporal reference picture (EP') of the second layer and the second layer A differential block (block ⑦) generated according to motion compensation after motion compensation is performed on the NXN block (②) for the differential picture (DP) between the base inter-layer reference pictures (ILP') obtained by up-sampling the 1-layer image. ) can be added to the sample value of the NxN block (②).

Alternatively, according to another embodiment of the present invention, in order to reduce the complexity of motion compensation, the temporal reference picture (EP′) of the second layer and the first layer picture according to the embodiment described based on FIGS. 5 to 7 . To perform motion compensation on the difference picture (DP) between the base inter-layer reference picture (ILP') or the second layer temporal reference picture (EP') and the base inter-layer reference picture (ILP') up-sampled. When the sub-pixel motion compensation process is omitted only for NxN blocks having only a specific reference picture index value, the prediction signal may be generated to have integer pixel precision. In this case, Equations 1 to 4 may be applied.

When information on the enhanced inter-layer reference picture (EILP) is generated through step S430, the decoder may generate a reference picture list used for inter prediction by using the inter-layer reference picture information (S440). That is, the current sub of the second layer and the decoding target picture (EP) using the base inter-layer reference picture (ILP) information and the enhanced inter-layer reference picture (EILP) information generated through steps S420 and S430 through this step. A reference picture list for can be generated. Reference picture information used when generating a reference picture lease may be a POC of a reference picture. The reference picture list may be generated by prediction units of the decoding apparatus and the encoding apparatus.

When the slice type of the current sub-picture to be decoded is P slice, the decoder stores the inter-layer reference picture (ILP) generated in step S420 in the reference picture list 0 (LIST0) and the enhanced inter-layer reference picture generated in step S430. (EILP) may be added at any position in the reference picture list. For example, after the positions of inter-layer reference pictures in the reference picture list are added to the last position, the positions may be changed using a reference picture list modification syntax or the like.

Alternatively, when the slice type of the current sub-picture to be decoded is P slice, the decoder may selectively add one of the inter-layer reference pictures generated in step S420 or step S430 to the reference picture list 0 (LIST0). The encoder may encode and transmit information on an inter-layer reference picture selected as information for constructing a reference picture list for each slice.

In order to select one of the inter-layer reference pictures generated in step S420 or S430, sum of absolute differences (SAD) between the original picture, that is, the second layer picture (EP) and the inter-layer reference picture (ILP) obtained through step S420 ) or SATD (sum of absolute transformed differences), and the SAD or SATD between the second layer picture (EP) and the enhanced inter-layer reference picture (EILP) obtained through step S430 may be compared. As a result of the comparison, an inter-layer reference picture picture having a smaller SAD or SATD may be included in the reference picture list. Alternatively, an inter-layer reference picture may be selected through SAD or SATD.

On the other hand, if the slice type of the current sub-picture to be decoded is B slice, the decoder adds the reference picture list 0 (LIST0) and the reference picture list 1 (LIST) to the inter-layer reference picture (ILP) generated in step S420 and The enhanced inter-layer reference picture (EILP) generated through step S430 may be added to an arbitrary position.

For example, after adding inter-layer reference pictures to the last position in the reference picture list, the decoder may change the positions using a reference picture list modification syntax or the like.

Alternatively, if the slice type of the current sub-picture to be decoded is B slice, the decoder adds the inter-layer reference picture (ILP) generated in step S420 to the reference picture list 0 (LIST0), and the reference picture list 1 ( LIST1), the enhanced inter-layer reference picture (EILP) generated through step S430 may be added.

Or conversely, the decoder adds the enhanced inter-layer reference picture (EILP) generated through step S430 to the reference picture list 0 (LIST0), and the inter-layer reference picture generated through step S420 to the reference picture list 1 (LIST1). (ILP) can be added.

According to another embodiment, when the slice type of the current sub-picture to be decoded is B slice, the decoder may selectively add only one inter-layer reference picture to the reference picture list. The encoder may encode and transmit information on an inter-layer reference picture selected as information for configuring the reference picture list for each slice. The decoder may construct a reference picture list by using information transmitted from the encoder.

For example, in order to select one of the inter-layer reference pictures generated in step S420 or step S430, SAD or SATD between the original picture, that is, the second layer picture (EP) and the inter-layer reference picture (ILP) obtained through step S420. and SAD or SATD between the second layer picture (EP) and the enhanced inter-layer reference picture (EILP) obtained through step S430 may be compared. As a result of the comparison, an inter-layer reference picture picture having a smaller SAD or SATD may be included in the bidirectional reference picture list.

Alternatively, between the SAD or SATD between the second layer picture (EP) and the inter-layer reference picture (ILP) obtained through step S420, and the enhanced inter-layer reference picture (EILP) obtained through the second layer picture (EP) and step S430 As a result of comparing the SAD or SATD, the SAD or SATD between the second layer picture (EP) and the inter-layer reference picture (EILP) is smaller than the SAD or SATD between the second layer picture (EP) and the inter-layer reference picture (ILP). The decoder may add a base inter-layer reference picture (ILP) to the reference picture list 0 (LIST 0) and an enhanced inter-layer reference picture picture (EILP) to the reference picture list 1 (LIST 1).

Of course, the reverse is also possible. That is, when the SAD or SATD between the second layer picture (EP) and the inter-layer reference picture (EILP) is smaller than the SAD or SATD between the second layer picture (EP) and the inter-layer reference picture (ILP), the decoder is a reference picture list An enhanced inter-layer reference picture picture (EILP) may be added to 0 (LIST 0), and a base inter-layer reference picture (ILP) may be added to the reference picture list 1 (LIST 1).

Or according to another embodiment, the SAD or SATD between the second layer picture (EP) and the inter-layer reference picture (ILP) obtained through step S420, and the enhanced inter-layer reference obtained through the second layer picture (EP) and step S430 As a result of comparing the SAD or SATD between pictures (EILP), the SAD or SATD between the second layer picture (EP) and the inter-layer reference picture (EILP) is the SAD between the second layer picture (EP) and the inter-layer reference picture (ILP) Alternatively, if greater than SATD, the decoder may add a base inter-layer reference picture (ILP) to the reference picture list 0 (LIST 0) and an enhanced inter-layer reference picture picture (EILP) to the reference picture list 1 (LIST 1). .

Conversely, when the SAD or SATD between the second layer picture (EP) and the inter-layer reference picture (EILP) is greater than the SAD or SATD between the second layer picture (EP) and the inter-layer reference picture (ILP), the decoder performs the reference picture An enhanced inter-layer reference picture picture (EILP) may be added to the list 0 (LIST 0), and a base inter-layer reference picture (ILP) may be added to the reference picture list 1 (LIST 1).

The decoder may apply Rate Distortion Optimization (RDO) or the like rather than SAD or SATD in the process of selecting the reference picture.

The contents of configuring the reference picture list described with reference to FIGS. 5 to 7 may be equally applied to the process of configuring the reference picture list in the encoder as well as the decoder.

As described above, according to the present invention, when encoding and decoding an image based on a multi-layer structure, a method of decoding an image capable of increasing the precision of lower-layer information that can be used as a prediction signal in encoding and decoding an image of an upper layer and an apparatus using the same.

To this end, when generating an improved inter-layer reference image, transmission of weight information may be omitted by performing motion compensation in units of integer pixels or applying weights based on encoding parameters.

In the above embodiment, the methods are described on the basis of a flowchart as a series of steps or blocks, but the present invention is not limited to the order of the steps, and some steps may occur in a different order or concurrently with other steps as described above. have. In addition, those of ordinary skill in the art will recognize that the steps shown in the flowchart are not exclusive, other steps may be included, or that one or more steps in the flowchart may be deleted without affecting the scope of the present invention. You will understand.

The above-described embodiments include examples of various aspects. It is not possible to describe every possible combination for representing the various aspects, but one of ordinary skill in the art will recognize that other combinations are possible. Accordingly, it is intended that the present invention cover all other substitutions, modifications and variations falling within the scope of the following claims.

100: video encoding device 111: motion prediction unit
112: motion compensation unit 120: intra prediction unit
115: switch 125: subtractor
130: transform unit 140: quantization unit
150: entropy encoding unit 160: inverse quantization unit
170: inverse transform unit 180: filter unit

Claims (20)

delete delete delete delete In the video decoding method supporting a plurality of layers,
decoding information on a first hierarchical picture that can be referenced by a second hierarchical picture to be decoded;
generating information of a reference picture between base layers by using the information of the first layer picture;
generating enhanced inter-layer reference picture information by using the first layer picture information, the base inter-layer reference picture information, and the second layer picture information;
Using the information of the base inter-layer reference picture, the information of the enhanced inter-layer reference picture, and the information of the second layer picture to generate a reference picture list in which the inter prediction of the second layer picture is used, and ,
The step of generating information of the reference picture between the base layers includes:
generating a first inter-layer reference picture in which a first layer picture size is mapped to a picture size of the second layer;
generating a second inter-layer reference picture in which the decoded temporal reference pictures of the first hierarchical picture are mapped to the size of the temporal reference picture of the second hierarchical picture,
The step of generating the enhanced inter-layer reference picture information comprises:
A first reference obtained by performing motion compensation on the target block using the reference picture of the second layer picture and the motion vector of the block of the first layer picture corresponding to the target block to be decoded of the second layer picture deriving a block;
deriving a second reference block obtained by performing motion compensation on the inter-layer corresponding block of the first inter-layer reference picture corresponding to the target block using the second inter-layer reference picture and the motion vector;
generating a difference block corresponding to a difference between the first reference block and the second reference block;
adding the inter-layer corresponding block to the residual block;
Further comprising the step of determining whether the reference picture index of the temporal reference picture of the first layer picture has a preset value,
When the reference picture index has the preset value, motion compensation using a motion interpolation filter is performed on the target block and the inter-layer corresponding block. In the video decoding method supporting a plurality of layers,
decoding information on a first hierarchical picture that can be referenced by a second hierarchical picture to be decoded;
generating information of a reference picture between base layers by using the information of the first layer picture;
generating enhanced inter-layer reference picture information by using the first layer picture information, the base inter-layer reference picture information, and the second layer picture information;
Using the information of the base inter-layer reference picture, the information of the enhanced inter-layer reference picture, and the information of the second layer picture to generate a reference picture list in which the inter prediction of the second layer picture is used, and ,
The step of generating information of the reference picture between the base layers includes:
generating a first inter-layer reference picture in which a first layer picture size is mapped to a picture size of the second layer;
generating a second inter-layer reference picture in which the decoded temporal reference pictures of the first hierarchical picture are mapped to the size of the temporal reference picture of the second hierarchical picture,
The step of generating the enhanced inter-layer reference picture information comprises:
A first reference obtained by performing motion compensation on the target block using the reference picture of the second layer picture and the motion vector of the block of the first layer picture corresponding to the target block to be decoded of the second layer picture deriving a block;
deriving a second reference block obtained by performing motion compensation on the inter-layer corresponding block of the first inter-layer reference picture corresponding to the target block using the second inter-layer reference picture and the motion vector;
generating a difference block corresponding to a difference between the first reference block and the second reference block;
and adding the inter-layer corresponding block to the residual block, wherein motion compensation performed to derive the first reference block and the second reference block is performed in units of integer pixels. delete delete In the video decoding method supporting a plurality of layers,
decoding information on a first hierarchical picture that can be referenced by a second hierarchical picture to be decoded;
generating information of a reference picture between base layers by using the information of the first layer picture;
generating enhanced inter-layer reference picture information by using the first layer picture information, the base inter-layer reference picture information, and the second layer picture information;
Using the information of the base inter-layer reference picture, the information of the enhanced inter-layer reference picture, and the information of the second layer picture to generate a reference picture list in which the inter prediction of the second layer picture is used, and ,
The step of generating information of the reference picture between the base layers includes:
generating a first inter-layer reference picture in which a first layer picture size is mapped to a picture size of the second layer;
generating a second inter-layer reference picture in which the decoded temporal reference pictures of the first hierarchical picture are mapped to the size of the temporal reference picture of the second hierarchical picture,
The step of generating the enhanced inter-layer reference picture information comprises:
generating a difference picture between a reference picture of the second layer picture and a reference picture between a second base layer;
Inter-layer correspondence of the reference picture between the first base layers corresponding to the target block by using the motion vector of the block of the first hierarchical picture corresponding to the target block to be decoded of the differential picture and the second hierarchical picture deriving a third reference block on which motion compensation is performed on the block;
merging the third reference block and the inter-layer corresponding block;
Further comprising the step of determining whether the reference picture index of the temporal reference picture of the first layer picture has a preset value,
When the reference picture index has the preset value, motion compensation using a motion interpolation filter is performed on the target block and the inter-layer corresponding block. In the video decoding method supporting a plurality of layers,
decoding information on a first hierarchical picture that can be referenced by a second hierarchical picture to be decoded;
generating information of a reference picture between base layers by using the information of the first layer picture;
generating enhanced inter-layer reference picture information by using the first layer picture information, the base inter-layer reference picture information, and the second layer picture information;
Using the information of the base inter-layer reference picture, the information of the enhanced inter-layer reference picture, and the information of the second layer picture to generate a reference picture list in which the inter prediction of the second layer picture is used, and , The step of generating the information of the reference picture between the base layer,
generating a first inter-layer reference picture in which a first layer picture size is mapped to a picture size of the second layer;
generating a second inter-layer reference picture in which the decoded temporal reference pictures of the first hierarchical picture are mapped to the size of the temporal reference picture of the second hierarchical picture,
The step of generating the enhanced inter-layer reference picture information comprises:
generating a difference picture between a reference picture of the second layer picture and a reference picture between a second base layer;
Inter-layer correspondence of the reference picture between the first base layers corresponding to the target block by using the motion vector of the block of the first hierarchical picture corresponding to the target block to be decoded of the differential picture and the second hierarchical picture deriving a third reference block on which motion compensation is performed on the block;
merging the third reference block and the inter-layer corresponding block;
The motion compensation performed to derive the third reference block is performed in units of integer pixels. delete delete delete delete In the video decoding apparatus supporting a plurality of layers,
an entropy decoding unit for decoding information on a first hierarchical picture that can be referenced by a second hierarchical picture to be decoded;
Inter-layer information is generated using the information of the first hierarchical picture, and information of the base inter-layer reference picture is improved using the information of the first hierarchical picture, the information of the base inter-layer reference picture, and the information of the second hierarchical picture. A reference picture in which inter-picture prediction of the second layer picture is generated by generating information of a reference picture, and using the information of the base inter-layer reference picture, the information of the enhanced inter-layer reference picture, and the information of the second layer picture A prediction unit for generating a list,
The prediction unit converts the first inter-layer reference picture obtained by mapping the first layer picture size to the picture size of the second layer and the decoded temporal reference pictures of the first layer picture as the temporal reference picture of the second layer picture. Further create a second base inter-layer reference picture mapped to the size of
The prediction unit performs motion compensation on the target block by using the reference picture of the second layer picture and the motion vector of the block of the first layer picture corresponding to the target block to be decoded of the second layer picture. A second reference block obtained by performing motion compensation on the inter-layer corresponding block of the first inter-layer reference picture corresponding to the target block using the first reference block and the second inter-layer reference picture and the motion vector derivation, generating a residual block corresponding to the difference between the first reference block and the second reference block, and generating the enhanced inter-layer reference picture information by adding the inter-layer corresponding block to the residual block;
The prediction unit determines whether a reference picture index of a temporal reference picture of the first hierarchical picture has a preset value,
and performing motion compensation using a motion interpolation filter on the target block and the inter-layer corresponding block when the reference picture index has the preset value. In the video decoding apparatus supporting a plurality of layers,
an entropy decoding unit for decoding information on a first hierarchical picture that can be referenced by a second hierarchical picture to be decoded;
Inter-layer information is generated using the information of the first hierarchical picture, and information of the base inter-layer reference picture is improved using the information of the first hierarchical picture, the information of the base inter-layer reference picture, and the information of the second hierarchical picture. A reference picture in which inter-picture prediction of the second layer picture is generated by generating information of a reference picture, and using the information of the base inter-layer reference picture, the information of the enhanced inter-layer reference picture, and the information of the second layer picture A prediction unit for generating a list,
The prediction unit converts the first inter-layer reference picture obtained by mapping the first layer picture size to the picture size of the second layer and the decoded temporal reference pictures of the first layer picture as the temporal reference picture of the second layer picture. Further create a second base inter-layer reference picture mapped to the size of
The prediction unit performs motion compensation on the target block by using the reference picture of the second layer picture and the motion vector of the block of the first layer picture corresponding to the target block to be decoded of the second layer picture. A second reference block obtained by performing motion compensation on the inter-layer corresponding block of the first inter-layer reference picture corresponding to the target block using the first reference block and the second inter-layer reference picture and the motion vector derivation, generating a residual block corresponding to a difference between the first reference block and the second reference block, adding the inter-layer corresponding block to the residual block to generate the improved inter-layer reference picture information, and the prediction unit and performing motion compensation in units of integer pixels when deriving the first reference block and the second reference block. delete delete In the video decoding apparatus supporting a plurality of layers,
an entropy decoding unit for decoding information on a first hierarchical picture that can be referenced by a second hierarchical picture to be decoded;
Inter-layer information is generated using the information of the first hierarchical picture, and information of the base inter-layer reference picture is improved using the information of the first hierarchical picture, the information of the base inter-layer reference picture, and the information of the second hierarchical picture. A reference picture in which inter-picture prediction of the second layer picture is generated by generating information of a reference picture, and using the information of the base inter-layer reference picture, the information of the enhanced inter-layer reference picture, and the information of the second layer picture A prediction unit for generating a list,
The prediction unit converts the first inter-layer reference picture obtained by mapping the first layer picture size to the picture size of the second layer and the decoded temporal reference pictures of the first layer picture as the temporal reference picture of the second layer picture. Further create a second base inter-layer reference picture mapped to the size of
The prediction unit generates a differential picture between a reference picture of the second hierarchical picture and a second inter-layer reference picture, and the first hierarchical picture corresponding to a target block to be decoded of the differential picture and the second hierarchical picture. A third reference block obtained by performing motion compensation on the inter-layer corresponding block of the first base inter-layer reference picture corresponding to the target block is derived using the motion vector of the block of , and the third reference block and the layer Generate the improved inter-layer reference picture information by summing the inter-corresponding blocks,
The prediction unit determines whether a reference picture index of a temporal reference picture of the first hierarchical picture has a preset value,
and performing motion compensation using a motion interpolation filter on the target block and the inter-layer corresponding block when the reference picture index has the preset value. In the video decoding apparatus supporting a plurality of layers,
an entropy decoding unit for decoding information on a first hierarchical picture that can be referenced by a second hierarchical picture to be decoded;
Inter-layer information is generated using the information of the first hierarchical picture, and information of the base inter-layer reference picture is improved using the information of the first hierarchical picture, the information of the base inter-layer reference picture, and the information of the second hierarchical picture. A reference picture in which inter-picture prediction of the second layer picture is generated by generating information of a reference picture, and using the information of the base inter-layer reference picture, the information of the enhanced inter-layer reference picture, and the information of the second layer picture A prediction unit for generating a list,
The prediction unit converts the first inter-layer reference picture obtained by mapping the first layer picture size to the picture size of the second layer and the decoded temporal reference pictures of the first layer picture as the temporal reference picture of the second layer picture. Further create a second base inter-layer reference picture mapped to the size of
The prediction unit generates a differential picture between a reference picture of the second hierarchical picture and a second inter-layer reference picture, and the first hierarchical picture corresponding to a target block to be decoded of the differential picture and the second hierarchical picture. A third reference block obtained by performing motion compensation on the inter-layer corresponding block of the first base inter-layer reference picture corresponding to the target block is derived using the motion vector of the block of , and the third reference block and the layer The image decoding apparatus of claim 1, wherein the improved inter-layer reference picture information is generated by summing inter-corresponding blocks, and the prediction unit performs motion compensation in units of integer pixels when deriving the third reference block.

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