KR20150009412A - Video coding/decoding method and apparatus for multi-layers - Google Patents

Abstract

According to the present invention, a method for decoding a video which supports a plurality of layers includes: a step of receiving position data about a position where an inter-layer reference picture set for at least a reference layer which the current picture can refer to is added to a reference picture list; a step of generating an initial reference picture list including the inter-layer reference picture set based on the position data; and a step of making prediction about the current picture based on the initial reference picture list. By doing so, a method for signaling position data about the position where the inter-layer reference picture is added to the reference picture list and a device using the same are provided.

Description

TECHNICAL FIELD [0001] The present invention relates to a method and apparatus for encoding and decoding an image supporting a plurality of layers,

The present invention relates to video compression techniques, and more particularly, to a method and apparatus for performing multi-layer video coding.

Recently, the demand for high resolution and high quality images such as high definition (HD) image and ultra high definition (UHD) image is increasing in various applications. As the image data has high resolution and high quality, the amount of data increases relative to the existing image data. Therefore, when the image data is transmitted using a medium such as a wired / wireless broadband line or stored using an existing storage medium, The storage cost is increased. High-efficiency image compression techniques can be utilized to solve such problems as image data becomes high-resolution and high-quality.

An inter picture prediction technique for predicting a pixel value included in a current picture from a previous or a subsequent picture of a current picture by an image compression technique, an intra picture prediction technique for predicting a pixel value included in a current picture using pixel information in the current picture, There are various techniques such as an entropy encoding technique in which a short code is assigned to a value having a high appearance frequency and a long code is assigned to a value having a low appearance frequency. Image data can be effectively compressed and transmitted or stored using such an image compression technique.

An embodiment of the present invention is directed to a method of generating a reference picture list including a picture of a different layer with respect to a layer to be currently encoded and decoded, and an apparatus using the same.

It is another object of the present invention to provide a method of adaptively incorporating pictures of different layers into a reference picture list according to the characteristics of a picture set and an apparatus using the same.

It is another object of the present invention to provide a method of dividing reference pictures of different layers into a reference picture list and an apparatus using the same.

Another embodiment of the present invention is to provide a method of adaptively incorporating reference pictures of different layers into a reference picture list according to a sequence of viewpoints, and an apparatus using the same.

It is another object of the present invention to provide a method of adaptively incorporating a picture of a different layer into a reference picture list according to a temporal sub-layer index value of a current picture and an apparatus using the same.

Another embodiment of the present invention is to provide a method of adaptively incorporating a picture of another layer into a reference picture list according to a difference of temporal sub-layer index values between layers and an apparatus using the same.

It is another object of the present invention to provide a method of signaling position information on a position where an interlayer reference picture is added to a reference picture list and an apparatus using the same.

The method of decoding an image supporting a plurality of layers according to an embodiment of the present invention includes decoding position information about a position at which an interlayer reference picture set for at least one reference layer to which a current picture can be referenced is added to a reference picture list Generating an initial reference picture list including the inter-layer reference picture set based on the position information, and performing prediction on the current picture based on the initial reference picture list, .

Further comprising the step of generating a short term reference picture set and a long term reference picture set which are composed of pictures existing in the same field for the current picture and wherein the step of generating the initial reference picture list comprises: It is possible to add an inter-layer reference picture set to the position of the initial reference picture list indicated by the position information.

The location information may be received in a slice header or a sequence header.

The step of receiving the position information includes receiving an identification flag indicating whether an identification index indicating a position at which an interlayer reference picture that can be referred to by the current picture is added to the initial reference picture list is transmitted, And if the identification flag is 1, receiving the identification index.

The identification flag can be received included in the video parameter set of each layer.

The identification index may be received in a slice header or a sequence header.

The initial reference picture list includes an initial reference picture list 0, the initial reference picture list 0 includes a short-term reference picture set including a short-term reference picture having a POC smaller than a Picture Of Count (POC) of the current picture, A short-term reference picture set composed of a short-term reference picture having a POC larger than the POC of the current picture, and a long-term reference picture set made up of a long-term reference picture.

The initial reference picture list 1 includes an initial reference picture list 1, the initial reference picture list 1 includes a short-term reference picture set including a short-term reference picture having a POC larger than a POC of the current picture, A short-term reference picture set made up of short-term reference pictures with a smaller POC than the POC of the picture, and a long-term reference picture set made up of long-term reference pictures.

Wherein the interlayer reference picture set includes a first sub-reference layer picture set and a second sub-reference layer picture set, wherein the first sub-reference layer picture set and the second sub- Can be sorted into a list.

Wherein the initial reference picture list includes an initial reference picture list 0 and the initial reference picture list 0 includes a short reference picture having a POC smaller than a POC of the current picture, , The first sub-reference layer picture set consisting of the multi-view reference picture set having a time order smaller than that of the current picture among the multi-view reference layer pictures, and a short reference picture set having a POC larger than the POC of the current picture A long-term reference picture set composed of a long-term reference picture, and a second sub-reference layer picture set composed of a picture having a time order larger than a time point of the current picture among the multi-view reference layer pictures have.

Wherein the initial reference picture list includes an initial reference picture list and the initial reference picture list includes a short reference picture having a POC that is larger than a POC of the current picture, , The second sub-reference layer picture set consisting of the multi-view reference layer picture having a view order larger than the viewpoint of the current picture, and a short reference picture having a POC smaller than the POC of the current picture A long-term reference picture set composed of long-term reference pictures, and a first sub-reference layer picture set composed of pictures having a time order smaller than a time point of the current picture among the multi-view reference layer pictures have.

And receiving flag information indicating whether the inter-layer reference picture set is divided into at least two sub-reference layer picture sets and added to the reference picture list.

And if the flag information is 1, receiving information on the number of sub-reference layer picture sets from which the inter-layer reference picture set is divided.

The generating of the inter-layer reference picture set may be based on a temporal sub-layer index (tempralId) of the current picture.

The step of generating the interlayer reference picture set may be generated based on the number of maximum time axis sublayers allowing interlayer prediction.

And modifying the initial reference picture list to generate a final reference picture list.

The step of performing the prediction on the current picture may use a reference picture included in the interlayer reference picture set as a reference picture of the current picture.

According to another aspect of the present invention, there is provided an apparatus for decoding an image that supports a plurality of layers, the apparatus including: an entropy decoding unit decoding information for predicting and decoding an image received through the BEAST SRE; Deriving a positional information on a position at which an inter-layer reference picture set for at least one reference layer to which the current picture can be referenced is added to a reference picture list, and based on the positional information, And a prediction unit for generating an initial reference picture list and performing a prediction on the current picture based on the initial reference picture list.

According to an embodiment of the present invention, there is provided a method of generating a reference picture list including pictures of different layers with respect to a layer to be currently encoded and decoded, and an apparatus using the same.

According to an embodiment of the present invention, there is provided a method of adaptively incorporating pictures of different layers into a reference picture list according to the characteristics of a picture set, and an apparatus using the same.

According to another embodiment of the present invention, there is provided a method of dividing reference pictures of different layers into a reference picture list and an apparatus using the same.

According to another embodiment of the present invention, there is provided a method of including a reference picture of a different layer adaptively in the order of a viewpoint in a reference picture list, and an apparatus using the same.

According to another embodiment of the present invention, there is provided a method of adaptively including a picture of another layer in a reference picture list according to a temporal sub-layer index value of a current picture, and an apparatus using the same.

According to another embodiment of the present invention, there is provided a method of embedding a picture of another layer adaptively into a reference picture list according to a difference of temporal sub-layer index values between layers, and an apparatus using the same.

According to another embodiment of the present invention, there is provided a method of signaling position information on a position where an interlayer reference picture is added to a reference picture list and an apparatus using the method.

1 is a block diagram schematically illustrating an encoding apparatus according to an embodiment of the present invention.
2 is a block diagram schematically illustrating a decoding apparatus according to an embodiment of the present invention.
3 is a conceptual diagram showing an example of a reference picture set including a short-term reference picture.
4 is a conceptual diagram for explaining a method of deriving the POC of the long-term reference picture.
5 is a diagram showing an example of constituting a reference picture list.
FIG. 6 is a conceptual diagram illustrating an example of constructing an inter-layer reference picture list according to an exemplary embodiment of the present invention.
7 is a diagram showing a configuration of a reference picture list O according to an example of the present invention.
8 is a diagram showing the structure of a reference picture list O according to another example of the present invention.
9 is a diagram illustrating the structure of a reference picture list 1 according to an example of the present invention.
10 is a diagram showing the structure of a reference picture list 1 according to another example of the present invention.
FIG. 11 illustrates a reference picture list constructed using a temporal sub-layer index according to an exemplary embodiment of the present invention.
12 shows a reference picture list constructed by using a multi-view reference picture according to an embodiment of the present invention.
13 is a diagram for explaining a method of generating a reference picture list according to an embodiment of the present invention.
14 is a diagram for explaining a method of generating a reference picture list according to another embodiment of the present invention.

The embodiments of the present invention and the respective components disclosed in the drawings disclose an independent configuration to represent different characteristic functions of the image encoding apparatus. It does not mean that each component is necessarily composed of separate hardware or a single software component unit. That is, each constituent unit is included in each constituent unit for convenience of explanation, and at least two constituent units of the constituent units may be combined to form one constituent unit, or one constituent unit may be divided into a plurality of constituent units to perform a function. The integrated embodiments and the separate embodiments of the components are also included in the scope of the present invention unless otherwise departing from the spirit of the present invention.

In addition, some of the components disclosed in the present invention are not essential components that perform essential functions in the present invention, but may be optional components only for improving performance. The present invention can be implemented only with components essential for realizing the essence of the present invention, except for the components used for the performance improvement, and can be implemented by only including the essential components except the optional components used for performance improvement Are also included in the scope of the present invention.

While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and will herein be described in detail. However, it is not intended to limit the invention to the specific embodiments. It is to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of the present invention. The singular expressions include plural expressions unless the context clearly dictates otherwise. In this specification, the terms "comprises" or "having" and the like refer to the presence of stated features, integers, steps, operations, elements, components, or combinations thereof, But do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, or combinations thereof.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. Hereinafter, the same reference numerals will be used for the same constituent elements in the drawings, and redundant explanations for the same constituent elements will be omitted.

Coding and decoding of video supporting a plurality of layers in a bitstream is referred to as scalable coding. Since there is a strong correlation between a plurality of layers, it is possible to remove redundant elements of data and enhance the coding performance of an image by performing prediction using such a relation. Performing prediction of a current layer to be predicted using information of another layer is hereinafter referred to as inter-layer prediction.

At least one of the plurality of layers may be different in resolution, frame rate, and color format, and upsampling or downsampling of the layer may be performed to adjust the resolution in inter-layer prediction.

1 is a block diagram schematically illustrating an encoding apparatus according to an embodiment of the present invention.

The encoding apparatus 100 according to the present invention includes an encoding unit 100a for an upper layer and an encoding unit 100b for a lower layer.

The upper layer may be represented by the current layer or enhancement layer, and the lower layer may be represented by a reference layer or a base layer. At least one of the resolution, the frame rate, and the color format may be different between the upper layer and the lower layer. Upsampling or downsampling of a layer may be performed when a resolution change is required to perform inter-layer prediction.

The encoding unit 100a of the upper layer includes a division unit 110, a prediction unit 100, an intra prediction unit 121, an inter picture prediction unit 122, an interlayer prediction unit 123, a conversion unit 130, A quantization unit 140, a rearrangement unit 150, an entropy encoding unit 160, an inverse quantization unit 170, an inverse transform unit 180, a filter unit 190, a memory 195, and a MUX 197 can do.

The encoding unit 100b of the lower layer includes a division unit 111, a prediction unit 125, an intra prediction unit 126, an inter prediction unit 127, a transform unit 131, a quantization unit 141, An inverse quantization unit 171, an inverse transform unit 181, a filter unit 191, and a memory 196, as shown in FIG.

The encoding unit may be implemented by the image encoding method described in the embodiments of the present invention, but operations in some components may not be performed for lowering the complexity of the encoding apparatus or for fast real-time encoding. For example, in performing intra-picture prediction in the prediction unit, it is not necessary to use a method of selecting an optimal intra-picture coding method using all the intra-picture prediction mode methods in order to perform coding in real time, The intra-picture prediction mode may be used as the final intra-picture prediction mode. As another example, it is also possible to restrictively use the type of the prediction block used in intra-picture prediction or inter-picture prediction.

The unit of the block processed by the encoding apparatus may be a coding unit for performing encoding, a prediction unit for performing prediction, and a conversion unit for performing conversion. The coding unit can be expressed by CU (Coding Unit), the prediction unit by PU (Prediction Unit), and the conversion unit by TU (Transform Unit).

In the division units 110 and 111, the layer image is divided into a plurality of encoding blocks, a prediction block, and a conversion block, and is divided into a coding block, a prediction block, Can be selected to divide the layer. For example, a recursive tree structure such as a quad tree structure can be used to divide an encoding unit in a layer image. Hereinafter, in the embodiment of the present invention, the meaning of a coding block may be used not only for a coding block but also for a block to perform decoding.

The prediction block may be a unit for performing prediction such as intra-picture prediction or inter-picture prediction. The block for intra prediction may be a square block such as 2Nx2N, NxN. As the blocks for performing the inter-picture prediction, 2NxN or Nx2N, which is a divided form of a square block or square block such as 2Nx2N or NxN, or a prediction block division using asymmetric AMP (Asymmetric Motion Partitioning) There is a way. The method of performing the transform in the transform unit 115 may vary depending on the type of the prediction block.

The prediction units 120 and 125 of the encoding units 100a and 100b include intra prediction units 121 and 126 for performing intra prediction and inter prediction units for performing inter prediction, 0.0 > 1122 < / RTI > The predicting unit 120 of the upper layer encoding unit 100a further includes an inter-layer predicting unit 123 that performs prediction on an upper layer using information of a lower layer.

The prediction units 120 and 125 can determine whether to use inter-picture prediction or intra-picture prediction for the prediction block. The unit of the processing block in which the prediction is performed and the unit of the processing block in which the prediction method is determined may be different. For example, in performing intra prediction, a prediction mode is determined based on a prediction block, and a process of performing prediction may be performed based on a conversion block. The residual value (residual block) between the generated prediction block and the original block can be input to the conversion units 130 and 131. In addition, the prediction mode information, motion vector information, and the like used for prediction can be encoded by the entropy encoding unit 130 and transmitted to the decoding apparatus together with the residual value.

When the PCM (Pulse Coded Modulation) coding mode is used, it is also possible to directly encode the original block and transmit it to the decoding unit without performing the prediction through the prediction units 120 and 125.

Intra prediction units 121 and 126 can generate a predicted block on the basis of reference pixels existing in the vicinity of the current block (block to be predicted). In the intra prediction method, the intra prediction mode may have a directional prediction mode in which reference pixel information is used according to a prediction direction, and a non-directional mode in which direction information is not used in prediction. The mode for predicting luma information and the mode for predicting chrominance information may be different types. Intra-frame prediction mode information in which luma information is predicted or predicted luma signal information can be utilized to predict color difference information. If a reference pixel is not available, a reference block that is not available may be replaced with another pixel to generate a prediction block.

The prediction block may include a plurality of transform blocks. When intra prediction is performed, if the size of the prediction block and the size of the transform block are the same, a pixel existing on the left side of the prediction block, In-picture prediction for the prediction block based on the pixels existing in the prediction block. However, when intra prediction is performed, when the size of the prediction block is different from the size of the transform block and a plurality of transform blocks are included in the prediction block, the intra prediction is performed using the reference pixels determined based on the transform block can do.

The intra-picture prediction method can generate a prediction block after applying a mode dependent intra-smoothing (MDIS) filter to the reference picture according to the intra-picture prediction mode. The type of MDIS filter applied to the reference pixel may be different. The MDIS filter is an additional filter applied to the in-picture predicted block after intra prediction is performed, and can be used to reduce the step that exists in the intra prediction block generated after performing the reference pixel and prediction. In performing MDIS filtering, the filtering of the reference pixel and some columns included in the intra prediction block can perform filtering according to the direction of the intra prediction mode.

The inter-picture prediction units 122 and 127 can perform prediction by referring to information of a block included in at least one of a previous picture of a current picture or a following picture. The inter-picture prediction units 122 and 127 may include a reference picture interpolating unit, a motion predicting unit, and a motion compensating unit.

In the reference picture interpolating unit, the reference picture information is supplied from the memories 195 and 196, and pixel information of an integer pixel or less can be generated in the reference picture. In the case of luma pixels, a DCT-based interpolation filter (DCT) based on a different filter coefficient may be used to generate pixel information of an integer number of pixels or less in units of quarter pixels. In the case of a color difference signal, a DCT-based 4-tap interpolation filter having a different filter coefficient may be used to generate pixel information of an integer number of pixels or less in units of 1/8 pixel.

The inter-picture prediction units 122 and 127 can perform motion prediction based on the reference pictures interpolated by the reference picture interpolating unit. Various methods such as Full Search-based Block Matching Algorithm (FBMA), Three Step Search (TSS), and New Three-Step Search Algorithm (NTS) can be used to calculate motion vectors. The motion vector may have a motion vector value of 1/2 or 1/4 pixel unit based on the interpolated pixel. The inter-picture prediction units 122 and 127 can perform prediction on the current block by applying one inter-picture prediction method among various inter-picture prediction methods.

As the inter picture prediction method, various methods such as a skip method, a merge method, and a motion vector prediction (MVP) method may be used.

In the inter-picture prediction, the motion information, that is, information such as an index of a reference picture, a motion vector, and a residual signal is entropy-encoded and transmitted to the decoding unit. When the skip mode is applied, residuals may not be generated, converted, quantized, or transmitted.

The inter-layer predicting unit 123 performs inter-layer prediction for predicting an upper layer using information of the lower layer. The inter-layer predicting unit 123 predicts inter-layer texture prediction, inter-layer inter prediction (i. E., Inter-layer inter prediction) using inter-layer texture, intra-picture prediction mode information, motion information, syntax information, ), Inter-layer syntax prediction, and the like.

The inter-layer texture prediction means that the texture of the reference block in the lower layer is used as a prediction sample of the current block of the upper layer. At this time, the texture of the reference block can be scaled by upsampling.

The inter-layer texture prediction includes an intra BL scheme for upsampling the reconstructed value of the reference block in the lower layer and encoding the residual value with the current block using the upsampled reference block as a prediction value for the current block, May be stored in a memory and a reference index scheme may be used in which the lower layer is used as a reference index.

The intra-picture prediction of the upper layer can be performed using the intra-picture prediction mode information of the lower layer, and the intra-picture prediction mode of the lower layer can be referred to as the BL intra mode.

Inter-layer motion prediction is also referred to as inter-layer inter prediction. According to inter-layer motion prediction, prediction of a current block of an upper layer can be performed using motion information of a lower layer. The motion information may include a motion vector and a reference picture index.

The inter-layer predicting unit 123 may also perform inter-layer syntax prediction that predicts or generates a texture of the current block using the syntax information of the lower layer. At this time, the syntax information of the lower layer used for predicting the current block may be information on intra-picture prediction mode, motion information, and the like.

As another example of inter-layer prediction, prediction of the current block is performed using the difference image generated by the difference value of the image obtained by upsampling the restored image of the upper layer and the restored image of the lower layer according to the inter-layer difference prediction .

As an example of inter-layer prediction, inter-layer texture prediction, inter-layer motion prediction, inter-layer syntax prediction, and inter-layer difference prediction have been described. However, inter-layer prediction applicable in the present invention is not limited to this.

A residual block including residue information which is a difference value between the prediction blocks generated by the prediction units 120 and 125 and the reconstruction blocks of the prediction blocks is generated and the residual blocks are input to the transform units 130 and 131. [

The transforming units 130 and 131 can transform the residual block using a transform method such as DCT (Discrete Cosine Transform) or DST (Discrete Sine Transform). Whether to apply the DCT or the DST to transform the residual block can be determined based on the intra prediction mode information and the prediction block size information of the prediction block used to generate the residual block. That is, the transforming units 130 and 131 can apply the transforming method differently according to the size of the prediction block and the prediction method.

The quantization units 140 and 141 may quantize the values converted into the frequency domain by the transform units 130 and 131. [ The quantization factor may vary depending on the block or the importance of the image. The values calculated by the quantization units 140 and 141 may be provided to the dequantization units 170 and 17 and the reordering units 150 and 151, respectively.

The reordering units 150 and 151 can reorder the coefficient values with respect to the quantized residual values. The reordering units 150 and 151 may change the two-dimensional block type coefficient to a one-dimensional vector form through a coefficient scanning method. For example, the rearrangement units 150 and 151 may scan a DC coefficient to a coefficient of a high frequency region using a Zig-Zag scan method, and change the DC coefficient to a one-dimensional vector form. A vertical scanning method of scanning a two-dimensional block type coefficient in a column direction instead of a jig-jag scanning method according to a size of a conversion block and an intra-picture prediction mode, and a horizontal scanning method of scanning a two- Can be used. That is, it is possible to determine whether any scan method among the jig-jag scan, the vertical scan and the horizontal scan is used according to the size of the conversion block and the intra prediction mode.

The entropy encoding units 160 and 161 can perform entropy encoding based on the values calculated by the reordering units 150 and 151. [ For entropy encoding, various encoding methods such as Exponential Golomb, Context-Adaptive Variable Length Coding (CAVLC), and Context-Adaptive Binary Arithmetic Coding (CABAC) may be used.

The entropy encoding units 160 and 161 receive the residual value coefficient information, the block type information, the prediction mode information, the division unit information, the prediction block information, and the transmission information of the encoding block from the reordering units 150 and 151 and the prediction units 120 and 125, The motion vector information, the reference frame information, the interpolation information of the block, and the filtering information, and perform entropy encoding based on a predetermined encoding method. In addition, the entropy encoding units 160 and 161 can entropy-encode the coefficient values of the encoding units input from the reordering units 150 and 151.

The entropy encoding units 160 and 161 may encode the intra-picture prediction mode information of the current block by performing binarization on the intra-picture prediction mode information. The entropy encoding units 160 and 161 may include a codeword mapping unit for performing such a binarization operation, and binarization may be performed differently depending on the size of a prediction block for performing intra prediction. In the codeword mapping unit, a codeword mapping table may be adaptively generated or stored in advance through a binarization operation. In another embodiment, the entropy encoding units 160 and 161 may represent the current intra prediction mode information using a codeword mapping unit that performs codeword mapping and a codeword mapping unit that performs codeword mapping. In the codeword mapping unit and the codeword mapping unit, a codeword mapping table and a codeword mapping table may be generated or stored.

The inverse quantization units 170 and 171 and the inverse transform units 180 and 181 dequantize the quantized values in the quantization units 140 and 141 and invert the converted values in the transform units 130 and 131. The residual values generated by the inverse quantization units 170 and 171 and the inverse transform units 180 and 181 are estimated through a motion estimation unit, a motion compensation unit, and an intra prediction unit included in the prediction units 120 and 125, It can be combined with the prediction block to generate a reconstructed block.

The filter units 190 and 191 may include at least one of a deblocking filter, an offset correction unit, and an Adaptive Loop Filter (ALF).

The deblocking filter can remove block distortion caused by the boundary between the blocks in the reconstructed picture. It may be determined whether to apply a deblocking filter to the current block based on pixels included in a few columns or rows included in the block to determine whether to perform deblocking. When a deblocking filter is applied to a block, a strong filter or a weak filter may be applied according to the deblocking filtering strength required. In applying the deblocking filter, the horizontal filtering and the vertical filtering may be performed concurrently when the vertical filtering and the horizontal filtering are performed.

The offset correction unit may correct the offset of the deblocked image with respect to the original image in units of pixels. In order to perform offset correction for a specific picture, pixels included in an image are divided into a predetermined number of areas, and then an area to be offset is determined and an offset is applied to the area. Alternatively, Can be used.

The ALF (Adaptive Loop Filter) can perform filtering based on a value obtained by comparing the filtered restored image and the original image. After dividing the pixels included in the image into at least one group, one filter to be applied to the group may be determined and different filtering may be performed for each group.

The filter units 190 and 191 may apply only the deblocking filter without applying the deblocking filter, the ALF, and the offset correcting unit, apply only the deblocking filter and the ALF, or apply only the deblocking filter and the offset correcting unit.

The memories 195 and 196 may store restored blocks or pictures calculated through the filter units 190 and 191 and the stored restored blocks or pictures may be provided to the predicting units 120 and 125 have.

The information output from the entropy encoding unit 100b of the lower layer and the information output from the entropy encoding unit 100a of the upper layer can be multiplexed by the MUX 197 and output as a bitstream.

The MUX 197 may be included in the lower layer encoding unit 100b or may be implemented as an independent device or module separate from the encoding unit 100. [

2 is a block diagram schematically illustrating a decoding apparatus according to an embodiment of the present invention.

As shown in FIG. 2, the decoding apparatus 200 includes a decoding unit 200a of an upper layer and a decoding unit 200b of a lower layer.

The decryption unit 200a of the upper layer includes an entropy decoding unit 210, a reordering unit 220, an inverse quantization unit 230, an inverse transformation unit 245, a prediction unit 250, a filter unit 260, a memory 240 ).

The lower layer decoding unit 200b includes an entropy decoding unit 211, a rearrangement unit 221, an inverse quantization unit 231, an inverse transformation unit 241, a prediction unit 251, a filter unit 261, a memory 271 ).

When a bitstream including a plurality of layers is transmitted from the encoding apparatus, the DEMUX 280 demultiplexes information for each layer and transmits the demultiplexed information to the decoding units 200a and 200b for the respective layers. The input bitstream can be decoded in a procedure opposite to that of the encoding apparatus.

The entropy decoding units 210 and 211 may perform entropy decoding in a procedure opposite to that in which entropy encoding is performed in the entropy encoding unit of the encoding apparatus. Information for generating a prediction block from the information decoded by the entropy decoding units 210 and 211 is supplied to the predicting units 250 and 251. The residual values obtained by performing entropy decoding in the entropy decoding unit are supplied to the rearranging units 220 and 221, As shown in FIG.

Similarly to the entropy encoding units 160 and 161, the entropy decoding units 210 and 211 may perform inverse transform using at least one of CABAC and CAVLC coefficient coding methods.

The entropy decoding units 210 and 211 can decode information related to the intra-picture prediction and the inter-picture prediction performed by the coding apparatus. The entropy decoding unit may include a codeword mapping table for generating a codeword including the codeword mapping unit in the in-picture prediction mode number. The codeword mapping table may be pre-stored or adaptively generated. When using the code-mapped mapping table, a code-mapped mapping unit for performing code-mapped mapping may additionally be provided.

The reordering units 220 and 221 can perform reordering based on a method in which the entropy decoding units 210 and 211 rearrange the entropy-decoded bitstreams in the encoding unit. The coefficients represented by the one-dimensional vector form can be rearranged by restoring the coefficients of the two-dimensional block form again. The reordering unit may perform reordering by receiving information related to the coefficient scanning performed by the encoding unit and performing a reverse scanning based on the scanning order performed by the encoding unit.

The inverse quantization units 230 and 231 may perform inverse quantization based on the quantization parameters provided by the encoding apparatus and the coefficient values of the re-arranged blocks.

The inverse transform units 240 and 241 may perform an inverse DCT and an inverse DST on the DCT and the DST performed by the transform units 130 and 131 with respect to the quantization result performed by the encoding apparatus. The inverse transform can be performed based on the transmission unit determined by the encoding apparatus. In the transform unit of the encoding apparatus, DCT and DST can be selectively performed according to a plurality of information such as a prediction method, a size and a prediction direction of a current block, and the inverse transform unit 225 of the decoding apparatus performs transform The inverse transformation can be performed based on the conversion information. Conversion can be performed based on an encoding block rather than a conversion block.

The prediction units 250 and 251 can generate prediction blocks based on the prediction block generation related information provided by the entropy decoding units 210 and 211 and the previously decoded blocks or picture information provided in the memories 270 and 271 .

The prediction units 250 and 251 may include a prediction unit determination unit, an inter-frame prediction unit, and an intra-frame prediction unit.

The prediction unit determination unit receives various information such as prediction unit information input from the entropy decoding unit, prediction mode information of the intra prediction method, motion prediction related information of the inter picture prediction method, and separates prediction blocks in the current coding block. It is possible to determine whether the inter-picture prediction is performed or the intra-picture prediction is performed.

The inter-picture prediction unit uses the information necessary for the inter-picture prediction of the current prediction block provided by the coding apparatus to predict the current picture based on the information included in at least one of the previous picture of the current picture or the following picture The inter-picture prediction can be performed. In order to perform the inter-picture prediction, the motion prediction method of the prediction block included in the encoded block is based on a skip mode, a merge mode, or an AMVP mode Can be determined.

The intra prediction unit can generate a prediction block based on the pixel information in the current picture. If the prediction block is a prediction block in which intra prediction is performed, intra prediction can be performed based on intra prediction mode information of the prediction block provided by the encoder. The intra-picture prediction unit includes an MDIS filter that performs filtering on reference pixels of a current block, a reference pixel interpolating unit that interpolates reference pixels to generate reference pixels of a pixel unit less than an integer value, Lt; RTI ID = 0.0 > DCF < / RTI >

The predicting unit 250 of the upper layer decoding unit 200a may further include an inter-layer predicting unit for performing inter-layer prediction for predicting an upper layer using information of a lower layer.

The inter-layer predicting unit may perform inter-layer texture prediction, inter-layer inter prediction, and inter-layer inter prediction using a texture of a lower layer, intra-picture prediction mode information, motion information, syntax information, Inter-layer syntax prediction, and the like.

A prediction using the texture of the reference block in the lower layer as the predicted value of the current block in the upper layer may be performed according to the inter-layer texture prediction. The texture of the reference block can be scaled by upsampling.

The inter-layer texture prediction includes an intra BL scheme for upsampling the reconstructed value of the reference block in the lower layer and using the upsampled reference block as a prediction value for the current block to code the residual value with the current block, Is stored in the memory and the stored base layer is used as the reference index.

The intra-picture prediction of the upper layer can be performed using the intra-picture prediction mode information of the lower layer, and the intra-picture prediction mode of the lower layer can be expressed in the BL intra mode.

According to the inter-layer motion prediction, the current block of the upper layer can be predicted using the motion information of the lower layer.

Also, the inter-layer predicting unit may perform inter-layer syntax prediction for predicting or generating a texture of a current block using syntax information of a lower layer. At this time, the syntax information of the lower layer used for predicting the current block may be information on intra-picture prediction mode, motion information, and the like.

The inter-layer predicting unit may perform inter-layer difference prediction for predicting a current block using a difference image generated by a difference value of an image obtained by upsampling a restored image of an upper layer and a restored image of a lower layer.

As an example of inter-layer prediction, inter-layer texture prediction, inter-layer motion prediction, inter-layer syntax prediction, and inter-layer difference prediction have been described. However, inter-layer prediction applicable in the present invention is not limited to this.

The reconstructed block or picture may be provided to the filter units 260 and 261. The filter units 260 and 261 may include a deblocking filter, an offset correction unit, and an ALF.

Information on whether or not a deblocking filter has been applied to the block or picture from the encoding device and information on whether a strong filter or a weak filter is applied can be provided when the deblocking filter is applied. In the deblocking filter of the decoding apparatus, the deblocking filter related information provided by the encoding apparatus is provided, and the decoding apparatus can perform deblocking filtering on the corresponding block.

The offset correction unit may perform offset correction on the reconstructed image based on the type of offset correction applied to the image and the offset value information during encoding.

The adaptive loop filter (ALF) performs filtering based on the comparison between the reconstructed image and the original image after filtering. The ALF can be applied to the encoding unit based on the ALF application information and the ALF coefficient information provided from the encoding apparatus. Such ALF information may be provided in a specific parameter set.

The memories 270 and 271 can store the reconstructed picture or block to be used as a reference picture or a reference block, and can also output the reconstructed picture.

The encoding apparatus and the decoding apparatus can perform encoding for three or more layers instead of two layers. In this case, the encoding unit for the upper layer and the decoding unit for the upper layer are arranged in a number corresponding to the number of the upper layers .

Hereinafter, in an embodiment of the present invention, a coding unit (coding unit) is used as a coding block for the sake of convenience of explanation, but it may be a block for performing coding as well as decoding. Hereinafter, a method of generating a reference picture list to be described with reference to the drawings according to an embodiment of the present invention may be implemented according to the functions of the respective modules described above with reference to FIGS. 1 and 2. The coding and decoding apparatuses ≪ / RTI >

As described above, in coding of an image supporting a multi-layer structure, a method of encoding / decoding an enhancement layer using a base layer motion information and texture information, a coding unit (CU) of a base layer, There is a method of encoding / decoding using a base layer that is up-sampled as a reference picture without changing the decoding method in units of a prediction unit (PU) or a prediction unit (PU). The latter scheme can be expressed in a reference picture index (RefIdx) mode.

When the reference picture index (RefIdx) mode is used, a picture already decoded by the enhancement layer can be used as a reference picture, or an image of a base layer or a lower layer can be upsampled and used as a reference picture.

Hereinafter, in the present invention, when an image of a base layer or a lower layer is upsampled and used as a reference picture, an upsampled base layer or a lower layer picture is referred to as an inter-layer reference picture.

In an image that supports a multi-view structure with respect to a multi viewpoint, inter prediction can be performed using a layer at a time other than the current layer as a reference picture. It can be expressed as a layer reference picture.

That is, when constructing a reference picture set of an enhancement layer for coding a picture, which is a multi-layer structure in which scalability is supported rather than a single layer, an interlayer reference picture must also be considered.

In general, the inter prediction may use at least one of a previous picture or a following picture of the current picture as a reference picture, and perform a prediction on the current block based on the reference picture. An image used for prediction of a current block is referred to as a reference picture or a reference frame.

The reference picture is specified by the reference picture index refIdx and a predetermined area in the reference picture is specified as a reference block through a motion vector.

An area in the reference picture can be represented using a reference picture index refIdx indicating a reference picture and a motion vector.

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

In the inter-picture prediction, the coding apparatus and the decoding apparatus derive the motion information of the current block, and then perform inter-picture prediction and / or motion compensation based on the derived motion information. At this time, the encoding apparatus and the decoding apparatus perform a motion of a collocated block corresponding to a current block in a restored neighboring block and / or a collocated picture already restored, By using information, coding / decoding efficiency can be improved.

Here, the reconstructed neighboring block may include a block adjacent to the current block and / or a block located at the outer corner of the current block, which is a block in the current picture reconstructed by decoding and / or decoding. The coding apparatus and the decoding apparatus may determine a predetermined relative position based on a block existing at a position spatially corresponding to the current block in the call picture, and determine a predetermined relative position based on the determined relative position The location of the call block can be derived based on the internal and / or external location of the block at the location where it is located. Here, for example, the call picture may correspond to one picture among the reference pictures included in the reference picture list.

Inter prediction can generate a prediction block such that the residual signal from the current block is minimized and the motion vector size is also minimized.

Meanwhile, the motion information derivation method can be changed according to the prediction mode of the current block. The prediction mode applied for inter prediction may be an Advanced Motion Vector Predictor (AMVP), a merge, or the like.

For example, when an Advanced Motion Vector Predictor (AMVP) is applied, the encoding apparatus and the decoding apparatus can generate a motion vector candidate list using a motion vector of a restored neighboring block and / or a motion vector of a call block. That is, the motion vector of the restored neighboring block and / or the motion vector of the call block may be used as a motion vector candidate. The encoding apparatus may transmit to the decoding apparatus a predicted motion vector index indicating an optimal motion vector selected from the motion vector candidates included in the list. At this time, the decoding apparatus can select the predicted motion vector of the current block from the motion vector candidates included in the motion vector candidate list using the motion vector index.

The encoding apparatus can obtain a motion vector difference (MVD) between a motion vector of a current block and a predictive motion vector, and can transmit the motion vector difference to a decoding apparatus. At this time, the decoding apparatus can decode the received motion vector difference, and derive the motion vector of the current block through the sum of the decoded motion vector difference and the predicted motion vector.

The encoding apparatus can also transmit a reference picture index or the like indicating the reference picture to the decoding apparatus.

The decoding apparatus predicts a motion vector of a current block using motion information of a neighboring block and derives a motion vector of the current block using residuals received from the encoding apparatus. The decoding apparatus can generate a prediction block for the current block based on the derived motion vector and the reference picture index information received from the encoder.

As another example, when a merge is applied, the encoding apparatus and the decoding apparatus can generate a merge candidate list using the motion information of the restored neighboring block and / or the motion information of the call block. That is, when motion information of the restored neighboring block and / or call block exists, the encoder and the decoder can use it as a merge candidate for the current block.

The encoding apparatus can select a merge candidate that can provide the optimal encoding efficiency among the merge candidates included in the merge candidate list as the motion information for the current block. At this time, a merge index indicating the selected merge candidate may be included in the bitstream and transmitted to the decoding apparatus. The decoding apparatus can select one of merge candidates included in the merge candidate list using the transmitted merge index and determine the selected merge candidate as the motion information of the current block. Therefore, when the merge mode is applied, the motion information of the restored neighboring block and / or call block can be used as it is as motion information of the current block. The decoding apparatus can restore the current block by adding residuals transmitted from the prediction block and the encoding apparatus.

In the above-described AMVP and merge modes, motion information of a restored neighboring block and / or motion information of a call block may be used to derive motion information of the current block.

In the case of the skip mode which is one of the other modes used for the inter-picture prediction, the information of the neighboring blocks can be used as it is for the current block. Therefore, in the case of the skip mode, the encoding apparatus does not transmit syntax information such as residuals to the decoding apparatus in addition to information indicating which block motion information is to be used as motion information of the current block.

The encoding apparatus and the decoding apparatus can perform motion compensation on the current block based on the derived motion information, thereby generating a prediction block of the current block. Here, the prediction block may be a motion compensated block generated as a result of performing motion compensation on a current block. In addition, a plurality of motion-compensated blocks may constitute one motion-compensated image.

The decoding apparatus can confirm skip flags, merge flags, and the like received from the encoding apparatus on information about motion information necessary for inter prediction of the current block, for example, motion vectors, reference picture indexes, and the like, and can derive corresponding information.

The processing unit in which the prediction is performed and the processing unit in which the prediction method and the concrete contents are determined may be different from each other. For example, the prediction mode may be determined for each prediction block, and the prediction may be performed on a conversion block basis, the prediction mode may be determined on a prediction block basis, and the intra prediction may be performed on a conversion block basis.

Pictures encoded / decoded prior to the current picture may be stored in a memory (e.g., a DPB) to be used for prediction of a current block (current picture). The list of pictures available for inter prediction of the current block is maintained in the reference picture list.

The P slice is a slice that is decoded through intra prediction or inter prediction using a maximum of one motion vector and one reference picture. The B slice is a slice that is decoded through intra prediction or inter prediction with two motion vectors and two reference pictures. At this time, the reference picture includes a short term reference picture and a long term reference picture. The picture may be specified by a picture order count (POC) indicating a display order. The short-term reference pictures may be pictures with a difference between the current picture and the POC, and the long-term reference pictures may be pictures .

Reference picture list 0 (hereinafter referred to as 'L0' for convenience of explanation) is a reference picture list used for inter prediction of P slice or B slice. Reference picture list 1 (hereinafter referred to as 'L1' for convenience of explanation) is used for inter prediction of B slices. Therefore, L0 is used for inter prediction of a block of a P slice performing unidirectional prediction, and L0 and L1 are used for inter prediction of a block of a B slice performing bidirectional prediction.

The decoding apparatus constructs a reference picture list when decoding is performed on the P slice and the B slice through inter prediction. The reference picture used for inter prediction is specified through the reference picture list. The reference picture index is an index indicating a reference picture on the reference picture list.

The reference picture list may be configured based on a reference picture set transmitted from the encoding apparatus. The reference picture set may be composed of a POC of a picture used as a reference picture and a flag (used_by_curr_pic_s0_flag) indicating whether the picture is directly referred to or not. The reference pictures constituting the reference picture list may be stored in a memory (e.g., a DPB). The pictures (the pictures encoded / decoded prior to the current picture) stored in the memory are managed by the encoder and the decoder.

3 is a conceptual diagram showing an example of a reference picture set including a short-term reference picture.

As shown in the figure, the reference picture set RPS includes, for each picture, a POC of a picture for a short-term reference picture to be stored in the DPB at the current time point, a flag for indicating whether or not a specific picture is directly referred to in the current picture Lt; / RTI > information.

For example, three pictures (pictures with POC 20, 19, 16) can be all referred to as short-term reference pictures during inter prediction of a picture having a POC of 21, and since the value of used_by_curr_pic_s0_flag is 1 in all three pictures, Is directly used for predicting a picture having 21 as shown in FIG.

On the other hand, all three pictures (POC 25, 24, and 20) can be referred to as short-term reference pictures in the inter prediction of the picture having the POC of 26, but the used_by_curr_pic_s0_flag value of the picture having the POC 25 is the picture having the POC of 24 and 20 Unlike the used_by_curr_pic_s0_flag value of 0, In this case, the picture having the POC of 25 is not directly used for the inter picture prediction of the picture having the POC of 26. [

A picture not shown in the reference picture set in the current picture may be removed from the DPB after an unused for reference is not used as a reference picture.

4 is a conceptual diagram for explaining a method of deriving the POC of the long-term reference picture.

As shown in the figure, in the case of the long-term reference picture, since the difference between the current picture and the POC is large, the least significant bit (LSB) and the most significant bit (MSB) of the POC can be used.

MaxPocLsb means the maximum value that can be represented by the LSB. If MaxPocLsb is 32, the long term reference picture (LTRF) with a POC of 84 can be expressed as 32 * 2 + 20, with the LSB being 20 and the MSB being 2.

In the case of the current picture with a POC of 338, the maximum value that can be expressed by the LSB is 32, which can be expressed as 32 * 10 + 11, so 10 is the MSB value and 11 is the LSB value.

delta_poc_msb_cycle_lt is a value for determining DeltaPocMsbCycleLt which is the MSB of POC in the long term reference picture set of the current picture. DeltaPocMsbCycleLt may correspond to the MSB difference value of the POC of the current picture and the POC of the reference picture.

 In the case of the long-term reference picture, the POC of the reference picture can be derived by using the LSB value of the POC of the reference picture and the MSB difference of the POC of the reference picture and the MSB of the POC of the current picture.

For example, a long reference picture (LTRP [0]) having a POC of the current picture of 331 and a POC of 308 indexed by 0 has an LSB value of 20, which is the MSB difference value between the MSB of the POC of the current picture and the POC of the reference picture 1 can be expressed as 331-1 * 32-11 + 20.

Likewise, if the MSB of the POC of the current picture and the MSB difference value of the POC of the reference picture are used as the LSB value 10, the long-term reference picture LTRP [1] having the POC index 170 indexed to 1 is 331-5 * 32- 11 + 10 < / RTI >

As shown in FIG. 3 and FIG. 4, an initial reference picture list that can be referred to by the current picture can be constructed with a list of pictures existing in the short-term reference picture buffer and the long-term reference picture buffer.

5 is a diagram showing an example of constituting a reference picture list.

The reference pictures include a first short term reference picture set (RefPicSetStCurr0) composed of reference pictures (Ref 1, Ref 2) smaller than the POC of the current picture Curr on the basis of the current picture and reference pictures And a long term reference picture set RefPicSetLtCurr which is composed of a second short term reference picture set RefPicSetStCurr1 and long term reference pictures Ref LT1 and Ref LT2.

At this time, the first short term reference picture set RefPicSetStCurr0 is composed of pictures having the used_by_curr_pic_s0_flag value of 1 (delta_poc_s0 with used_by_curr_pic_s0_flag = 1) and the second short term reference picture set RefPicSetStCurr1 is also composed of pictures having the used_by_curr_pic_s1_flag value of 1 (Delta_poc_s1 with used_by_curr_pic_s1_flag = 1).

The initial reference picture list can be composed of a set of reference picture sets having different properties.

The reference picture list 0, that is, L0 is configured in the order of a first short-term reference picture set (RefPicSetStCurr0), a second short-term reference picture set (RefPicSetStCurr1), and a long-term reference picture set (RefPicSetLtCurr), as shown in Fig.

On the other hand, the reference picture list 1, that is, L1 is configured in the order of the second short term reference picture set (RefPicSetStCurr1), the first short term reference picture set (RefPicSetStCurr0), and the long term reference picture set (RefPicSetLtCurr).

The number of reference pictures that can be included in the reference picture list can be determined based on information transmitted from the encoding apparatus. For example, after configuring the reference picture list, the encoding apparatus determines the number of reference pictures to be used and sets information (e.g., num_ref_idx_lX_default_active_minus1, X = 0 or 1) about the number of reference pictures to be used as a Sequence Parameter Set ) To the decoding apparatus. The decoding apparatus can use the number of reference pictures identified by a value obtained by adding 1 to num_ref_idx_lX_default_active_minus1 received as a default value in the current sequence.

In addition, when the number of reference pictures is to be specified for each picture or slice, the coding apparatus sets additional information (e.g., num_ref_idx_l1_active_minus1, X = 0 or 1) indicating the number of reference pictures to a picture parameter set (PPS ) Or a slice header or the like. The decoding apparatus can apply a value specified by adding 1 to the received num_ref_idx_l1_active_minus1 as the number of reference pictures for the current picture or the current slice.

In performing the inter prediction, motion compensation may be performed using the reference pictures specified in the reference picture list constructed as described above.

In a multi-layer structure providing spatial scalability or multi-point scalability, the reference picture of the enhancement layer can be composed of reference pictures on the same layer and an interlayer reference picture.

In this case, the signaling for the interlayer reference picture may be performed through information identifying the layer and information identifying the reference picture. For example, the nuh_layer_id value, which is present in the same access unit as the current picture of the i-th layer and is included in the NAL (Network Abstraction Layer) unit header and transmitted, is a j-th layer identifier , It can be determined that the corresponding picture is used as a reference picture for the current picture. The interlayer reference pictures can be displayed with long term reference pictures.

RefPicLayerId is a value that can be signaled by the syntax element inter_layer_pred_layer_idc included in the slice header, and refers to a layer that the current layer refers to in the interlayer prediction.

FIG. 6 is a conceptual diagram illustrating an example of constructing an inter-layer reference picture list according to an exemplary embodiment of the present invention.

6, the initial reference picture list includes a short-term reference picture set (RefPicSetStCurrBefore [i] (hereafter referred to as a first reference picture set) composed of short-term reference pictures with a lower POC than the POC of the current picture, (RefPicSetStCurr After [i], hereinafter referred to as a second reference picture set), a long term reference picture set sequence (RefPicSetLtCurr [i], hereinafter referred to as a third reference picture set) and a short reference picture set And an interlayer reference picture set (RefPicSetILCurr [i], hereinafter referred to as a fourth reference picture set).

The reference picture included in the fourth reference picture set may be a picture of a layer supporting spatial scalability or may be a picture included in a layer supporting a point scalability or a depth scalabilit or an image quality scalabilit It may be a picture of a supporting layer. At this time, the spatial scalability and the picture quality scalable vector can be coded with the same codec structure.

If the bitstream supports more than one scalability, the reference picture for each scalabililty can consist of a single set of reference pictures. When one reference picture set is constructed for a plurality of scaler bilities, information on the order of the scalability type arranged in the reference picture set can be transmitted from the encoding apparatus to the decoding apparatus.

On the other hand, a reference picture set may be separately configured for each of a plurality of scalabilities. That is, a fourth reference picture set, a fifth reference picture set, a sixth reference picture set, and the like, which are composed of inter-layer reference pictures in addition to the first reference picture set, the second reference picture set, and the third reference picture set, . Such an inter-layer reference picture set can be adaptively added to the reference picture list according to the frequency of occurrence. For example, a reference picture set with a high frequency of occurrence may be allocated to a low index of the reference picture list.

The initial reference picture list of Fig. 6 is L0 in which the first reference picture set is composed in the lowest order of the list. At this time, the fourth reference picture set can be added in the last order of the initial reference picture list L0.

The initial reference picture list 0 is composed of pictures having flag information (used_by_curr_pic_flag) 1 indicating whether the reference pictures included in each reference picture set are used as reference pictures. As shown, the initial reference picture list 0 may be composed of only the first and second pictures among the four pictures included in each reference picture set.

The initial reference picture list can be modified per picture or slice, and the reference pictures can be modified according to the change. The initial reference picture list can be changed by the syntax elements included in the slice hair (for example, ref_pic_list_modification_flag_10, list_entry_l0, ref_pic_list_modification_flag_l1, list_entry_l1).

ref_pic_list_modification_flag_l0 and ref_pic_list_modification_flag_l1 indicate whether or not they are explicitly transmitted from the encoding apparatus to the decoding apparatus in the reference picture list 0 and the reference picture list 1. When the flag value is 1, the reference picture list is explicitly specified And if the flag value is 0, the reference picture list is implicitly guided to the initial reference picture set.

If the flag value is 1, list_entry_l0 indicates specific entry information constituting a reference picture list relating to L0, that is, an index of a reference picture, and list_entry_l1 indicates specific entry information constituting a reference picture list relating to L1.

Through this modification, the final reference picture list 0 includes the first and second reference pictures (0, 1) of the first reference picture set, the first and second reference pictures (0, 1) of the second reference picture set, And the first reference picture (0) of the 4 reference picture set.

According to another example of the present invention, when the reference picture list is constructed, the fourth reference picture sets for the interlayer reference pictures may be arranged in the order other than the last in the list of Fig. In the multi-layer structure, since there is a strong correlation between the enhancement layer and the base layer due to characteristics of the image, it often occurs to refer to the interlayer reference picture. The encoding performance of the reference picture list can be improved by adding an interlayer reference picture with a high frequency of occurrence to a position other than the end of the reference picture list.

In consideration of this point, the interlayer reference pictures can be added to various positions of the reference picture list. FIGS. 7 to 10 are conceptual diagrams illustrating an example of constructing an inter-layer reference picture list according to other examples of the present invention.

FIG. 7 illustrates the structure of the reference picture list O according to an example of the present invention. As shown in FIG. 7, a fourth reference picture set, which is an interlayer reference picture set, may be arranged in the second order of the reference picture list.

The reference picture list O is composed of a first reference picture set, a fourth reference picture set, a second reference picture set, and a third reference picture set in this order.

The reference picture list 0 is composed of pictures having flag information (used_by_curr_pic_flag) 1 indicating whether or not the reference pictures included in each reference picture set are used as reference pictures. As shown, the initial reference picture list 0 may be composed of only the first and second pictures among the four pictures included in each reference picture set.

The initial reference picture list configured in this manner can be modified for each picture or slice, and the entries of the reference pictures can be modified according to the change.

Through this modification, the final reference picture list 0 includes the first and second reference pictures (0, 1) of the first reference picture set, the first and second reference pictures (0, 1) of the fourth reference picture set, And the first reference picture (0) of the second reference picture set.

8 is a diagram showing the structure of a reference picture list O according to another example of the present invention.

8, the reference picture list O includes a first reference picture set composed of short-term reference pictures having a POC smaller than the POC of the current picture, a second reference picture set having a POC larger than the POC of the current picture, A fourth reference picture set composed of inter-layer reference pictures, and a third reference picture set composed of long-term reference pictures.

Or the reference picture list O is a first reference picture set including a short reference picture in which a fourth reference picture set composed of interlayer reference pictures is arranged first and a POC is smaller than the POC of the current picture as shown in <b> of FIG. 8, A second reference picture set made up of short-term reference pictures having a larger POC than the POC of the current picture, and a third reference picture set made up of long-term reference pictures.

In the case of < b &gt;, there is an advantage that encoding and decoding efficiency of the reference picture list can be enhanced when the frequency of referring to the interlayer reference picture is high.

Alternatively, according to another embodiment, similar to creating a single-layer reference picture list, a first reference picture set composed of short-term reference pictures having a POC smaller than the POC of the current picture, a short reference picture having a higher POC than the POC of the current picture, And a third reference picture set composed of a long-term reference picture, and then specify a position at which the interlayer reference picture is to be added in the slice or sequence level, that is, the slice header or the sequence parameter header.

It is possible to construct a reference picture list by adding an interlayer reference picture from the specified position. Such signaling may be included in a slice header, a sequence header, or a video parameter set and may be encoded and transmitted to a decoding apparatus.

FIG. 9 illustrates the structure of the reference picture list 1 according to an embodiment of the present invention. As shown in FIG. 9, the fourth reference picture set, which is an interlayer reference picture set, may be arranged in the last order of the reference picture list.

The reference picture list 1 is composed of a second reference picture set, a first reference picture set, a third reference picture set, and a fourth reference picture set in this order.

The reference picture list 1 is composed of pictures in which flag information (used_by_curr_pic_flag) indicating whether or not the reference pictures included in each reference picture set is used as a reference picture is 1. As shown, the initial reference picture list 1 can be composed of only the first and second pictures among the four pictures included in each reference picture set.

The initial reference picture list configured in this manner can be modified for each picture or slice, and the entries of the reference pictures can be modified according to the change.

Through this modification, the final reference picture list 1 includes the first reference picture (0) of the second reference picture set, the first and second reference pictures (0, 1) of the first reference picture set, And the first and second reference pictures (0, 1).

10 is a diagram showing a configuration of a reference picture list 1 according to another example of the present invention.

10, the reference picture list 1 includes a second reference picture set composed of short-term reference pictures having a larger POC than a POC of the current picture, a first reference picture composed of short-term reference pictures having a lower POC than the POC of the current picture, A fourth reference picture set composed of inter-layer reference pictures, and a third reference picture set composed of long-term reference pictures.

Or the reference picture list 1 is assigned a second reference picture set composed of short-term reference pictures having a larger POC than the POC of the current picture in the first order as shown in <b> of FIG. 10, A set can be assigned in the second order. Next, the reference picture list 1 can be configured in the order of a first reference picture set made up of short-term reference pictures with a smaller POC than the POC of the current picture and a third reference picture set made up of long-term reference pictures.

Alternatively, similar to creating a single-layer reference picture list, a second reference picture set including a short reference picture having a POC larger than the POC of the current picture, a first reference picture including a short reference picture having a POC lower than the POC of the current picture, And a third reference picture set composed of long-term reference pictures, and then specify a position at which the interlayer reference picture is to be added at the slice or sequence level, that is, the slice header or the sequence parameter header.

It is possible to construct a reference picture list by adding an interlayer reference picture from the specified position. Such signaling may be included in a slice header, a sequence header, or a video parameter set and may be encoded and transmitted to a decoding apparatus.

According to another embodiment of the present invention, an arrangement order of inter-layer reference picture sets may be set according to a temporal sub-layer index (tempralId) of the current picture.

FIG. 11 illustrates a reference picture list constructed using a temporal sub-layer index according to an exemplary embodiment of the present invention.

In the multi-layer structure, the frequency of using an interlayer reference picture may vary depending on the temporal sub-layer of the current picture belonging to the enhancement layer. As temporal sub-layer index value tempralId increases, it may be effective to perform inter-prediction by referring to a picture in the same layer rather than referring to reference pictures of other layers.

In other words, if tempralId is small, it is effective for coding to refer to a picture of the interlayer than the same layer. The larger the tempralId is, the more coding is used as a picture of the same layer than the interlayer as a reference picture Can be efficient.

In this embodiment, considering the temporal sub-layer index temporalId considering the temporal sub-layer different reference frequency of the inter-layer picture, the position of adding the inter-layer reference picture to the initial reference picture list may be changed adaptively have.

11 is a diagram showing the configuration of the reference picture list 0 when the tempralId value is 0 to 2.

When the TempralId value is 0, since the enhancement layer is likely to perform inter-layer prediction, a fourth reference picture set composed of inter-layer reference pictures can be added at the beginning of the initial reference picture list.

The initial reference picture list composed of the pictures having the flag information (used_by_curr_pic_flag) 1 indicating whether or not the reference pictures included in the respective reference picture sets are used as reference pictures is stored in the four pictures 0 , 1, 2, and 3), and first and second pictures (0, 1) included in the first reference picture set, the second reference picture set, and the third reference picture set.

As shown in the figure, after the reference picture list initial value is set, the final reference picture list can be set after correcting the reference picture list. Information modifying the reference picture list can be signaled to the slice header.

The modified final reference picture list 0 includes the first and second pictures (0, 1) of the first reference picture set, the first and second pictures (0, 1) of the fourth reference picture set, And the first picture (0).

When the tempralId value is 1, a fourth reference picture set made up of inter-layer reference pictures can be added to the initial reference picture list 0 after the first reference picture set.

An initial reference picture list including pictures with flag information (used_by_curr_pic_flag) indicating whether or not the picture is used as a reference picture is included in the first reference picture set, the fourth reference picture set, the second reference picture set, and the third reference picture set And the first and second pictures (0, 1).

The modified final reference picture list 0 includes the first and second pictures (0, 1) of the first reference picture set, the first and second pictures (0, 1) of the fourth reference picture set, And the first picture.

When TempralId is 2, there is a high possibility that inter prediction between the same layer is performed more than the interlayer prediction of the enhancement layer. Therefore, a fourth reference picture set composed of an interlayer reference picture is set to a third reference picture set Next can be added at the end.

An initial reference picture list 0 composed of pictures with flag information (used_by_curr_pic_flag) indicating whether or not the picture is used as a reference picture is stored in a first reference picture set, a second reference picture set, a third reference picture set and a fourth reference picture set And the first and second pictures (0,1) included therein.

The modified final reference picture list includes the first and second pictures (0, 1) of the first reference picture set, the first and second pictures (0, 1) of the second reference picture set, Th picture (0).

Similar to the above, the initial reference list L1 can also be changed in the position where the fourth reference picture set is added according to the temporalId value. For example, when the temporalId value is 0, the initial reference list L1 can be configured in the order of a fourth reference picture set, a second reference picture set, a first reference picture set, and a third reference picture set, and if the temporalId value is 1 A second reference picture set, a fourth reference picture set, a first reference picture set, and a third reference picture set. If the temporalId value is as large as 2, the fourth reference picture set can be added in the last order of the initial reference list L1.

In summary, as shown in FIG. 11, the position at which the interlayer reference picture is added to the initial reference picture list can be adaptively changed according to the temporalId value of the current picture.

On the other hand, when the current picture refers to a plurality of layers, that is, when the number of inter-layer reference pictures is many, a plurality of reference pictures are divided into a plurality of inter-layer reference picture sets. A plurality of inter-layer reference picture sets may be arranged in a different order to the initial reference picture set.

For example, in a video supporting multi-view scalability, when a plurality of viewpoints, that is, a plurality of layers are used as reference pictures, a fourth reference picture set composed of interlayer reference pictures is divided and included in the reference picture list . The reference picture list can be configured in various ways according to the view order of the layer of the current layer and the reference picture or the degree of proximity of the viewpoint.

A layer having a smaller difference between the current layer and the viewpoint is more likely to use the picture of the layer as an interlayer reference picture. In other words, the greater the difference between the current layer and the viewpoint, the lower the probability that the current picture will be referred to. According to this embodiment, the order in which the reference pictures are added to the reference picture list can be adaptively changed according to the frequency of occurrence of the reference pictures, that is, the close order considering the degree of reference between the viewpoints. That is, the position at which the interlayer reference picture is added to the reference picture list can be adaptively determined according to the number of interlayer reference pictures and the order of the interlayer reference pictures.

A lower index of a reference picture list is assigned to a reference picture of a layer having a small difference between a current layer and a viewpoint and a higher index of a reference picture list can be assigned to a reference picture of a layer having a larger difference between the current layer and the viewpoint.

FIG. 12 illustrates a reference picture list constructed using multi-view reference pictures according to an example of the present invention.

12, the reference picture 0, the reference picture 1, the reference picture 2, and the reference picture 0 and the reference picture 1 of the reference picture 3 that can be included in the multi-view reference picture set are arranged in front of the reference picture list 0 Reference pictures 2 and 3 can be arranged after the first reference picture set composed of short-term reference pictures.

In this case, the reference picture 0 and the reference picture 1 may be reference pictures of a layer having a small difference between the current layer and the viewpoint, and the reference pictures 2 and reference pictures 3 may be pictures having a large difference between the current layer and the viewpoint.

According to another example, the reference picture 0, which is the first interlayer reference picture, is arranged in the first order of the initial reference picture list, and the reference picture 1, which is the second interlayer reference picture, is arranged in the first reference picture set The interlayer reference pictures thereafter can be sequentially added after the long-term reference picture set composed of the long-term reference pictures.

The difference value between the current layer and the reference layer that can be aligned in the front side in the reference picture list may be a default value or may be variably set in the encoding apparatus and transmitted to the decoding apparatus.

When adding the inter-layer reference picture set to the initial reference picture list, the information on the criterion for applying the position to the initial reference picture list may be fixed to a fixed value in the encoding apparatus, may be included in the VPS to be signaled to the decoding apparatus have.

In the reference picture list 1, a reference picture of a layer having a small difference between a current layer and a viewpoint may be arranged at the front of an initial reference picture list, and a second reference picture set composed of a short reference picture whose POC is larger than the POC of the current picture . The reference picture set of the reference pictures having a large difference between the current layer and the viewpoint may be arranged at the rear of the initial reference picture list or in the order of the third reference picture set composed of the long-term reference pictures.

Or a reference picture of a layer having a large difference between a current layer and a viewpoint may be arranged at the front of the initial reference picture list or may be arranged after a second reference picture set composed of short-term reference pictures having a larger POC than the POC of the current picture. The reference picture set of reference pictures having a small difference between the current layer and the viewpoint may be arranged at the rear of the initial reference picture list or in the order of the third reference picture set composed of long-term reference pictures.

Although the multi-view reference picture is included in the inter-layer reference picture set of Fig. 12, even when the type of scalability is spatial scalability and pictures of a plurality of layers are used as reference pictures, The configuration of the list can be applied. That is, the reference pictures may be divided and added to the reference picture list in accordance with the difference of the ID (dependency ID) identifying the current picture and the spatial layer.

As described above, when the reference picture list includes the inter-layer reference picture set, the location where the inter-layer reference picture set is added can be variously set, and there can also be multiple ways of signaling the inter-layer reference picture set.

13 is a diagram for explaining a method of generating a reference picture list according to an embodiment of the present invention.

First, the decoding apparatus generates a short-term reference picture set and a long-term reference picture set composed of pictures existing in the same area for the current picture (S1310).

The short-term reference picture set may include a short-term reference picture set including a short-term reference picture having a POC smaller than the POC of the current picture and a short-term reference picture set including a short-term reference picture having a POC higher than the POC of the current picture.

The long-term reference picture set is composed of long-term reference pictures having a large POC difference from the current picture.

First, the initial reference picture list 0 is composed of a short-term reference picture set consisting of a short-term reference picture with a POC smaller than the POC of the current picture, a short-term reference picture set consisting of a short-term reference picture having a POC larger than the POC of the current picture, .

The initial reference picture list 1 also includes a short-term reference picture set consisting of a short-term reference picture having a larger POC than the POC of the current picture, a short-term reference picture set consisting of a short-term reference picture having a POC smaller than the POC of the current picture, .

The decoding apparatus derives position information on a position to which the interlayer reference picture set is to be added (S1320). Such position information is information signaled from the encoding device to the decoding device, and may be transmitted in a slice or a sequence level, for example, in a slice header or a sequence header.

In the case of a bit stream supporting a plurality of view layers such as a multi-view scalability, the feature of each layer image is different and the correlation with the base layer reconstructed image is often different. In addition, the temporalId value for each multi-layer may be different, and the frequency at which the inter-layer reference occurs may vary depending on the temporalId value.

According to these various conditions, since the most optimal position to add an interlayer reference picture for each layer may be different, a position to add an interlayer reference picture for each layer may be signaled.

When the position information is derived, the decoding apparatus adds the inter-layer reference picture set to the corresponding position of the initial reference picture list indicated by the position information (S1330).

The inter-layer reference picture set may be generated before the location information is derived, or may be generated simultaneously with the inter-layer reference picture added to the initial reference picture list after the location information is derived.

The initial reference picture list is composed of pictures having flag information (used_by_curr_pic_flag) 1 indicating whether the reference pictures included in the reference picture set are used as reference pictures.

At this time, the order of the reference picture sets arranged in the initial reference picture list can be variably set according to the position information.

For example, the initial reference picture list 0 includes a short-term reference picture set consisting of short-term reference pictures with a smaller POC than the POC of the current picture, an interlayer reference picture set, a short-term reference picture composed of short- And a long-term reference picture set composed of long-term reference pictures.

The initial reference picture list 1 includes a short-term reference picture set including a short-term reference picture having a POC larger than the POC of the current picture, an interlayer reference picture set, a short-term reference picture set consisting of a short-term reference picture having a POC smaller than the POC of the current picture, And a long-term reference picture set composed of pictures.

Or the inter-layer reference picture set includes a plurality of sub-inter-layer reference picture sets, and when these sub-reference layer picture sets are separated and added to the initial reference picture list, the position information is a position at which each sub- And the like.

For example, in the case of a layer for which the re-point scalability is supported, the initial reference picture list 0 includes a short-term reference picture set composed of short-term reference pictures with a POC smaller than the POC of the current picture, A short term reference picture set composed of short term reference pictures having a POC larger than the POC of the current picture, a long term reference picture set made up of long term reference pictures, And a subinterlare reference picture set consisting of pictures having a time order larger than a time point of the current picture.

The initial reference picture list 1 includes a short-term reference picture set composed of short-term reference pictures having a larger POC than the POC of the current picture, a subinterla- tive reference picture set composed of pictures having a time order larger than the starting point of the current picture, A long term reference picture set consisting of a short term reference picture having a POC smaller than the POC of the current picture and composed of a long term reference picture and a picture having a time order smaller than the time point of the current picture among the multi- And a layer reference picture set.

Or an interlayer reference picture set may be generated based on the temporal sub-layer index (tempralId) of the current picture or based on the number of maximum temporal sub-layers that allow inter-layer prediction.

For example, as the temporal sub-layer index (tempralId) of the current picture becomes smaller, the inter-layer reference picture set may be arranged in a lower order of the initial reference picture set. In this case, The position can be signaled.

Alternatively, the smaller the difference between the temporal sub-layer index tempralId of the current picture and the temporal sub-layer index of the reference layer is, the more the inter-layer reference picture set can be sorted in the lower order of the initial reference picture set. The concrete location where the picture set is added can be signaled.

If the final reference picture list is generated through modification of the reference picture list, or if the initial reference picture list is not modified based on the final reference picture list, the decoding apparatus performs prediction on the current picture based on the initial reference picture list, And decodes the current picture (S1340).

At the time of prediction for the current picture, the reference picture included in the inter-layer reference picture set is displayed by the long-term reference picture, and the decoding apparatus uses the reference picture included in the inter-layer reference picture set as the reference picture of the current picture.

On the other hand, in order to signal the position at which the interlayer reference picture is added, the coding apparatus calculates a bit distortion ratio (Rate Distortion) considering the image quality in relation to the number of bits at each position where the interlayer reference picture can be added, To determine where the interlayer reference pictures can be added. In this case, the encoding operation amount to be performed by the encoding apparatus can be increased.

In order to reduce the amount of computation in the encoding step while maintaining the diversity of images for each multi-layer, the encoding device restricts the number of positions at which reference pictures are to be added to a predetermined number and sets a position at which the inter- , The bit distortion rate can be calculated only for the set position. An optimal position at which an interlayer reference picture can be added can be derived based on the calculated bit distortion rate, and the coding apparatus can transmit the position to the decoding apparatus.

For example, it can be set that an interlayer reference picture can be added at three positions as follows: the first, short-term reference picture set of the initial reference picture list, and the long-term reference picture set. In this case, the encoding apparatus can encode an indication index of a position at which an interlayer reference picture is added among three positions and signal it.

Indexes for identifying the positions and positions where the interlayer reference pictures are added can be mapped as shown in Table 1.

Referring to Table 1, when an interlea reference picture is added at the beginning of the reference picture list, the index is set to 0. When the interlea reference picture is added after the short-term reference picture set, the index is set to 1, In this case, the index can be set to 2.

The position at which the interlayer reference picture is added to each layer or each slice may be changed. In this case, the identification index may be signaled for each layer or for each slice.

In addition, an indication flag indicating whether or not an identification index indicating a position to add an interlayer reference picture is transmitted may be included in a video parameter set of each layer and signaled.

14 is a diagram for explaining a method of generating a reference picture list according to another embodiment of the present invention.

First, the decoding apparatus receives an identification flag indicating whether or not an identification index indicating a position where an interlayer reference picture for each layer is added to the initial reference picture list is transmitted, and determines whether the identification index is transmitted based on the received identification flag (S1410)

This identification flag can be included in the video parameter set of each layer and signaled.

If the identification flag is 1 (S1420), the decoding apparatus receives and derives an identification index, and derives a position where an interlayer reference picture for each layer is added to the initial reference picture list (S1430).

The position at which the interlayer reference picture is added can be mapped to the identification index as shown in Table 1 and the decoding apparatus can derive the position at which the interlayer reference picture is added using the lookup table shown in Table 1. [

On the other hand, if the identification flag is 0 (S1420), the decoding apparatus can recognize the position information on the position where the interlayer reference picture set is added in the preset reference picture list (S1440). Then, in step S1450, the decoding apparatus adds an inter-reference picture set to a corresponding position of the initial reference picture list designated by the position information preset to the default value, thereby constructing an initial reference picture list.

The decoding apparatus can perform prediction on the current picture based on the initial reference picture list and perform decoding on the current picture (S1460).

Steps S1450 and S146 are similar to steps S1330 and S1330 of Fig. 13, so duplicate descriptions are omitted.

According to the present invention, flag information indicating whether an inter-layer reference picture set is divided into at least two sub-reference layer picture sets and added to the reference picture list can be signaled. That is, flag information for easily knowing whether or not the inter-layer reference picture set is divided into two or more sub-reference layer picture sets can be encoded in the encoding apparatus and transmitted to the decoding apparatus.

As described above, if the reference picture for the multi-view layer is divided into a plurality of sub-reference layer picture sets, the flag information becomes 1.

If the flag information is 1, information on the number of sub-reference layer picture sets from which the inter-layer reference picture set is divided can be additionally signaled.

Further, when the flag information is &quot; 1 &quot;, the identification flag and the identification index described above may be signaled.

As described above, according to the present invention, there is provided a method of generating a reference picture list including a picture of a different layer with respect to a layer to be currently encoded and decoded, and an apparatus using the same.

The inter-layer reference picture set included in the reference picture list may be classified according to the characteristics of the picture set, for example, according to the temporal sub-layer index value of the current picture, The reference picture list can be adaptively added to the reference picture list.

A method and an apparatus for signaling position information on a position at which an interlayer reference picture is added to a reference picture list are also included in the scope of the present invention. The location information may be individually coded and signaled, and may be signaled with index information indicating a predetermined limited location.

In the above-described exemplary system, 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 different orders or simultaneously . In addition, since the above-described embodiments may include examples of various aspects, a combination of each embodiment should also be understood as an embodiment of the present invention. Accordingly, it is intended that the invention include all alternatives, modifications and variations that fall within the scope of the following claims.

100: encoding device 200: decryption device
100a: Encoding unit of upper layer 100b: Encoding unit of lower layer
200a: upper layer decoding unit 200b: lower layer decoding unit

Claims (34)

A method of decoding an image supporting a plurality of layers,
Receiving positional information about a position at which an inter-layer reference picture set for at least one reference layer to which the current picture can be referenced is added to the reference picture list;
Generating an initial reference picture list including the inter-layer reference picture set based on the position information;
And performing prediction on the current picture based on the initial reference picture list. The method according to claim 1,
Generating a short-term reference picture set and a long-term reference picture set, which are composed of pictures existing in the same area for the current picture,
Wherein the step of generating the initial reference picture list adds the interlayer reference picture set to the position of the initial reference picture list indicated by the position information based on the position information. The method according to claim 1,
Wherein the position information is included in a slice header or a sequence header. The method according to claim 1,
Wherein the step of receiving the location information comprises:
Receiving an identification flag indicating whether an identification index indicating a position at which an interlayer reference picture that can be referred to by the current picture is added to the initial reference picture list is transmitted;
And if the identification flag is 1, receiving the identification index. 5. The method of claim 4,
Wherein the identification flag is included in a video parameter set of each layer and is received. 5. The method of claim 4,
Wherein the identification index is included in a slice header or a sequence header. The method according to claim 1,
The initial reference picture list includes an initial reference picture list 0,
The initial reference picture list 0
A short-term reference picture set consisting of short-term reference pictures with a smaller POC than the Picture Of Count (POC) of the current picture,
The interlayer reference picture set,
A short-term reference picture set including a short-term reference picture having a POC larger than the POC of the current picture,
And a long-term reference picture set composed of long-term reference pictures. The method according to claim 1,
The initial reference picture list includes an initial reference picture list 1,
The initial reference picture list 1
A short-term reference picture set including a short-term reference picture having a POC larger than the POC of the current picture,
The interlayer reference picture set,
A short-term reference picture set including a short-term reference picture whose POC is smaller than the POC of the current picture,
And a long-term reference picture set composed of long-term reference pictures. The method according to claim 1,
The interlayer reference picture set includes a first sub-reference layer picture set and a second sub-reference layer picture set,
Wherein the first sub-reference layer picture set and the second sub-reference layer picture set are separated and arranged in the initial reference picture list. 10. The method of claim 9,
The inter-layer reference picture set includes a multi-view reference layer picture,
The initial reference picture list includes an initial reference picture list 0,
The initial reference picture list 0
A short-term reference picture set including a short-term reference picture whose POC is smaller than the POC of the current picture,
The first sub-reference layer picture set including a picture having a view order smaller than a viewpoint of the current picture among the multi-view reference layer pictures,
A short-term reference picture set including a short-term reference picture having a POC larger than the POC of the current picture,
A long-term reference picture set comprising long-term reference pictures,
And the second sub-reference layer picture set including a picture having a view order larger than a viewpoint of the current picture among the multi-view reference layer pictures. 10. The method of claim 9,
The inter-layer reference picture set includes a multi-view reference layer picture,
The initial reference picture list includes an initial reference picture list 1,
The initial reference picture list 1
A short-term reference picture set including a short-term reference picture having a POC larger than the POC of the current picture,
The second sub-reference layer picture set including a picture having a view order larger than a viewpoint of the current picture among the multi-view reference layer pictures,
A short-term reference picture set including a short-term reference picture whose POC is smaller than the POC of the current picture,
A long-term reference picture set comprising long-term reference pictures,
And the first sub-reference layer picture set including a picture having a view order smaller than a viewpoint of the current picture among the multi-view reference layer pictures. The method according to claim 1,
Further comprising the step of receiving flag information indicating whether the inter-layer reference picture set is divided into at least two sub-reference layer picture sets and added to the reference picture list. 13. The method of claim 12,
And if the flag information is 1, receiving information on the number of sub-reference layer picture sets from which the inter-layer reference picture set is separated. The method according to claim 1,
Wherein the step of generating the inter-layer reference picture set is generated based on a temporal sub-layer index (tempralId) of the current picture. The method according to claim 1,
Wherein the step of generating the inter-layer reference picture set is generated based on the number of maximum time-base sub-layers that allow inter-layer prediction. The method according to claim 1,
And modifying the initial reference picture list to generate a final reference picture list. The method according to claim 1,
Wherein the step of predicting the current picture uses a reference picture included in the interlayer reference picture set as a reference picture of the current picture. An apparatus for decoding an image supporting a plurality of layers,
An entropy decoding unit for decoding information for predicting and decoding an image received through the beast slip;
Deriving a positional information on a position at which an inter-layer reference picture set for at least one reference layer to which the current picture can be referenced is added to a reference picture list, and based on the positional information, And a prediction unit for generating an initial reference picture list and performing a prediction on the current picture based on the initial reference picture list. 19. The method of claim 18,
Wherein the predicting unit further generates a short-term reference picture set and a long-term reference picture set, which are composed of pictures existing in the same region for the current picture,
And adds the interlayer reference picture set to the position of the initial reference picture list indicated by the position information based on the position information. 19. The method of claim 18,
Wherein the position information is included in a slice header or a sequence header. 19. The method of claim 18,
Wherein the predicting unit derives an identification flag indicating whether an identification index indicating a position where an interlayer reference picture that can be referred to by the current picture is added to the initial reference picture list is transmitted, And the index is derived. 22. The method of claim 21,
Wherein the identification flag is included in a video parameter set of each layer. 22. The method of claim 21,
Wherein the identification index is included in a slice header or a sequence header. 19. The method of claim 18,
The initial reference picture list includes an initial reference picture list 0,
The initial reference picture list 0
A short-term reference picture set consisting of short-term reference pictures with a smaller POC than the Picture Of Count (POC) of the current picture,
The interlayer reference picture set,
A short-term reference picture set including a short-term reference picture having a POC larger than the POC of the current picture,
And a long-term reference picture set composed of long-term reference pictures. 19. The method of claim 18,
The initial reference picture list includes an initial reference picture list 1,
The initial reference picture list 1
A short-term reference picture set including a short-term reference picture having a POC larger than the POC of the current picture,
The interlayer reference picture set,
A short-term reference picture set including a short-term reference picture whose POC is smaller than the POC of the current picture,
And a long-term reference picture set composed of long-term reference pictures. 19. The method of claim 18,
The interlayer reference picture set includes a first sub-reference layer picture set and a second sub-reference layer picture set,
Wherein the first sub-reference layer picture set and the second sub-reference layer picture set are separated and arranged in the initial reference picture list. 27. The method of claim 26,
The inter-layer reference picture set includes a multi-view reference layer picture,
The initial reference picture list includes an initial reference picture list 0,
The initial reference picture list 0
A short-term reference picture set including a short-term reference picture whose POC is smaller than the POC of the current picture,
The first sub-reference layer picture set including a picture having a view order smaller than a viewpoint of the current picture among the multi-view reference layer pictures,
A short-term reference picture set including a short-term reference picture having a POC larger than the POC of the current picture,
A long-term reference picture set comprising long-term reference pictures,
And the second sub-reference layer picture set including a picture having a view order larger than a viewpoint of the current picture among the multi-view reference layer pictures. 27. The method of claim 26,
The inter-layer reference picture set includes a multi-view reference layer picture,
The initial reference picture list includes an initial reference picture list 1,
The initial reference picture list 1
A short-term reference picture set including a short-term reference picture having a POC larger than the POC of the current picture,
The second sub-reference layer picture set including a picture having a view order larger than a viewpoint of the current picture among the multi-view reference layer pictures,
A short-term reference picture set including a short-term reference picture whose POC is smaller than the POC of the current picture,
A long-term reference picture set comprising long-term reference pictures,
And the first sub-reference layer picture set consisting of a picture having a view order smaller than a viewpoint of the current picture among the multi-view reference layer pictures. 19. The method of claim 18,
Wherein the predicting unit derives flag information indicating whether the interlayer reference picture set is divided into at least two sub-reference layer picture sets and added to the reference picture list. 30. The method of claim 29,
Wherein the predicting unit further derives information on the number of sub-reference layer picture sets from which the inter-layer reference picture set is divided, if the flag information is 1. 19. The method of claim 18,
Wherein the predicting unit generates the initial reference picture list based on a temporal sub-layer index (tempralId) of the current picture. 19. The method of claim 18,
Wherein the predicting unit generates the initial reference picture list based on the number of maximum time axis sublayers that allow interlayer prediction. 19. The method of claim 18,
Wherein the predicting unit modifies the initial reference picture list to generate a final reference picture list. 19. The method of claim 18,
Wherein the predicting unit uses a reference picture included in the inter-layer reference picture set as a reference picture of the current picture.

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