WO2013115609A1 - Interlayer prediction method and device for image signal - Google Patents

Description

Interlayer prediction method of video signal and apparatus therefor

The present invention relates to a video encoding and decoding method, and more particularly to a multi-layered video encoding and decoding method.

In the conventional scalable video encoding, interlayer texture prediction, interlayer motion information prediction, and interlayer residual signal prediction techniques are used to remove redundancy existing between layers. However, a technique for removing redundancy between intra prediction modes of each layer is not used. In addition, the current HEVC standard uses an intra prediction mode in more directions than the existing H.264. Since the intra prediction mode of HEVC is not made with a multi-layer structure in mind, there is a problem that more improvements are required to be applied to a video encoder / decoder having a multi-layer structure based on HEVC.

SUMMARY OF THE INVENTION An object of the present invention is to provide a multi-layer structure-based image encoding and decoding method for reducing encoding efficiency and complexity by removing redundancy of intra prediction mode information between layers in intra prediction encoding of a block to be encoded in a higher layer. will be.

The present invention provides a multi-layer video encoding method including a first layer including a current encoding target block and a second layer, which is a reference lower layer of the first layer, wherein the second layer corresponds to the encoding target block. Determining a corresponding block; And encoding the encoding object block by using an intra prediction mode of the corresponding block in the second layer.

The determining of the corresponding block in the second layer may specify the sample position of the corresponding block in the second layer corresponding to the reference sample position of the encoding target block in consideration of the size ratio between input images.

The encoding of the encoding target block using the intra prediction mode of the corresponding block in the second layer may be performed when the corresponding block in the second layer is encoded in the intra prediction mode.

When the corresponding block in the second layer is not available or is encoded by inter prediction, the encoding target block may be encoded in a first layer using a normal intra picture prediction method.

When the corresponding block in the second layer is not available or is encoded by inter prediction, the intra prediction mode of the corresponding block in the second layer is regarded as a predetermined intra prediction mode (eg, a DC mode). Can be used to encode a block to be encoded.

The encoding of the encoding object block may generate a prediction signal of the encoding object block by using an intra prediction mode of the corresponding block in the second layer.

The encoding of the encoding target block may use the intra prediction mode of the corresponding block in the second layer as a Most Probable Mode (MPM) candidate mode of the encoding target block.

The encoding of the encoding target block may include an intra prediction mode of at least one of an upper prediction block and an intra prediction mode of a left neighboring block of the encoding target block that is an MPM target block. Can be replaced with

In the encoding of the encoding target block, the intra prediction mode of the second layer corresponding block may be used as the MPM candidate mode together with the intra prediction modes of the upper neighboring block and the left neighboring block of the encoding target block. .

The present invention also provides a multi-layer video decoding method including a first layer including a current decoding target block and a second layer which is a reference lower layer of the first layer, wherein the intra prediction mode of the corresponding block of the second layer is included. It provides a multi-layer image decoding method comprising the step of decoding the decoding target block using.

The multi-layer video decoding method may specify a corresponding block in the second layer by specifying a sample position of the second layer corresponding to a reference sample position of the decoding target block in consideration of the size ratio between input images.

The decoding of the decoding object block may further include determining whether the decoding object block uses an intra prediction mode of the second layer correspondence block. When the intra prediction mode is used, the decoding object block may be decoded using the intra prediction mode of the second layer. The decoding may be performed when the decoding object block does not use the intra prediction mode of the second layer. It can be decoded through a conventional intra prediction prediction method.

Determining whether the intra prediction mode of the second layer corresponding block is used may be performed in a sequence parameter sets (SPS), a picture parameter sets (PPS), a slice segment, a coding unit, or a prediction unit.

The decoding of the decoding object block may generate a prediction signal of the decoding object block by using an intra prediction mode of the second layer corresponding block.

In the decoding of the decoding object block, the intra prediction mode of the second layer corresponding block may be used as a MPM candidate mode of the decoding object block.

The decoding of the decoding object block may include an intra prediction mode of at least one of an intra prediction mode of an upper neighboring block and a left neighboring block of the decoding object block that is an MPM target block. Can be replaced with

In the decoding of the decoding object block, the intra prediction mode of the second layer corresponding block may be used as the MPM candidate mode together with the intra prediction modes of the upper neighboring block and the left neighboring block of the decoding object block. .

The present invention also provides a multi-layer video encoding method including a first layer including a current encoding target block and a second layer, which is a reference lower layer of the first layer, wherein the second layer corresponding to the encoding target block. Determining corresponding blocks in the apparatus; And encoding the encoding target block by using an intra prediction mode of the corresponding block in the second layer. The multi-layer video encoding method and the present invention include a first layer including a current decoding target block. And a second layer which is a reference lower layer of the first layer, the multi-layer image decoding method comprising: decoding the decoding target block using an intra prediction mode of the second layer block. A computer readable recording medium having recorded thereon a program for executing a structural image decoding method on a computer is provided.

The present invention also provides a multi-layer video encoding apparatus including a first layer including a current encoding target block and a second layer that is a reference lower layer of the first layer, wherein the intra prediction mode of the corresponding block of the second layer is included. Provided is a multi-layer video encoding apparatus including an intra prediction unit for encoding the encoding target block using.

The intra predictor may specify a second hierarchical block corresponding to the encoding target block by specifying a sample position of the second layer corresponding to a reference sample position of the encoding target block in consideration of a size ratio between input images.

The intra prediction unit may encode the encoding target block using the intra prediction mode of the second layer block when the block of the second layer is encoded in the intra prediction mode.

When the corresponding block in the second layer is not available or is encoded by inter prediction, the encoding target block may be encoded in a first layer using a conventional intra picture prediction method.

When the corresponding block in the second layer is not available or is encoded by inter prediction, the intra prediction mode of the corresponding block in the second layer is regarded as a predetermined intra prediction mode (eg, a DC mode). Can be used to encode a block to be encoded.

The intra prediction unit may generate a prediction signal of the encoding target block by using an intra prediction mode of the second layer corresponding block.

The intra prediction unit may use an intra prediction mode of the second layer corresponding block as a Most Probable Mode (MPM) candidate mode of the encoding target block.

The encoding of the encoding target block may include an intra prediction mode of at least one of an upper prediction block and an intra prediction mode of a left neighboring block of the encoding target block that is an MPM target block. Can be replaced with

In the encoding of the encoding target block, the intra prediction mode of the second layer corresponding block may be used as the MPM candidate mode together with the intra prediction modes of the upper neighboring block and the left neighboring block of the encoding target block. .

The present invention also provides a multi-layer video decoding apparatus including a first layer including a current decoding target block and a second layer that is a reference lower layer of the first layer, wherein the intra prediction mode of the second layer block is used. A multi-layer video decoding apparatus including an intra predictor for decoding the decoding target block is provided.

Determining whether the intra prediction mode of the second layer corresponding block is used, wherein the decoding step is configured to perform intra prediction mode of the second layer when the decoding target block uses the intra prediction mode of the second layer. The decoding object block may be decoded using the intra-prediction decoding method. When the decoding object block does not use the intra prediction mode of the second layer, the decoding object block may be decoded using a normal intra prediction decoding method.

Determining whether the intra prediction mode of the second layer corresponding block is used may be performed in a sequence parameter sets (SPS), a picture parameter sets (PPS), a slice segment, a coding unit, or a prediction unit.

The intra predictor may specify a second layer corresponding block corresponding to the decoding object block by specifying a sample position of the second layer corresponding to a reference sample position of the decoding object block in consideration of a size ratio between input images. .

The intra prediction unit may decode the decoding object block using the intra prediction mode of the second layer block when the decoding object block is encoded using the intra prediction mode of the second layer.

If the intra prediction block does not use the intra prediction mode of the second layer, the intra predictor may decode the signal through a conventional intra prediction decoding method.

The intra predictor may generate a prediction signal of the decoding object block by using an intra prediction mode of the second layer block.

The intra predictor may use the intra prediction mode of the second layer block as a Most Probable Mode (MPM) candidate mode of the decoding target block.

The decoding of the decoding object block may include an intra prediction mode of at least one of an intra prediction mode of an upper neighboring block and a left neighboring block of the decoding object block that is an MPM target block. Can be replaced with

In the decoding of the decoding object block, the intra prediction mode of the second layer corresponding block may be used as the MPM candidate mode together with the intra prediction modes of the upper neighboring block and the left neighboring block of the decoding object block. .

In the multi-layer structure-based image encoding and decoding method according to the present invention, in intra prediction encoding an encoding target block of an upper layer, a method of using intra prediction mode of a corresponding block of a lower layer is provided, thereby providing inter-layer intra prediction. By eliminating redundancy for mode information, it has the effect of improving coding efficiency and reducing complexity.

1A and 1B are block diagrams illustrating a configuration of an image encoding apparatus according to an embodiment of the present invention.

2A and 2B are block diagrams illustrating a configuration of an image decoding apparatus according to an embodiment of the present invention.

3 is a flowchart of a multi-layer video encoding method according to an embodiment of the present invention.

4 is a diagram illustrating a relationship between an encoding target block and a lower layer block corresponding to an encoding target block in the multi-layer video encoding method according to an embodiment of the present invention.

FIG. 5 is a diagram for generating a prediction signal of an encoding target block using an intra prediction mode of a lower layer block in a multi-layer video encoding method according to an embodiment of the present invention.

6 is a diagram illustrating a case in which all of information of neighboring blocks of an encoding target block cannot be used.

FIG. 7 is a diagram illustrating a case in which information on a left neighboring block used in the MPM candidate mode of a block to be encoded is not available.

8 is a diagram illustrating a case where information of a left neighboring block and an upper neighboring block used as MPM information of a block to be encoded is the same.

9 is a diagram illustrating a case where the value of the intra prediction mode of the upper neighboring block and the left neighboring block of the encoding target block is different.

FIG. 10 is a diagram illustrating a case where the value of the intra prediction mode of the upper neighboring block and the left neighboring block of the encoding target block is different.

11 is a flowchart of a multi-layer video decoding method according to an embodiment of the present invention.

As the inventive concept allows for various changes and numerous embodiments, particular embodiments will be illustrated in the drawings and described in detail in the written description.

However, this is not intended to limit the present invention to specific embodiments, it should be understood to include all modifications, equivalents, and substitutes included in the spirit and scope of the present invention.

Terms such as first and second may be used to describe various components, but the components should not be limited by the terms. The terms are used only for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, the first component may be referred to as the second component, and similarly, the second component may also be referred to as the first component. The term and / or includes a combination of a plurality of related items or any item of a plurality of related items.

When a component is said to be "connected" or "connected" to another component, it may be directly connected to or connected to that other component, but it may be understood that another component may be present in the middle. Should be. On the other hand, when a component is said to be "directly connected" or "directly connected" to another component, it should be understood that there is no other component in between.

The terminology used herein is for the purpose of describing particular example embodiments only and is not intended to be limiting of the invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In this application, the terms "comprise" or "have" are intended to indicate that there is a feature, number, step, operation, component, part, or combination thereof described in the specification, and one or more other features. It is to be understood that the present disclosure does not exclude the possibility of the presence or the addition of numbers, steps, operations, components, components, or combinations thereof.

Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art. Terms such as those defined in the commonly used dictionaries should be construed as having meanings consistent with the meanings in the context of the related art and shall not be construed in ideal or excessively formal meanings unless expressly defined in this application. Do not.

1A and 1B are block diagrams illustrating a configuration of an image encoding apparatus according to an embodiment of the present invention. An image encoding apparatus according to an embodiment of the present invention includes a plurality of layers of image encoding apparatuses. FIG. 1A is a block diagram illustrating a lower layer image encoding apparatus 100a according to an embodiment of the present invention, and FIG. 1B is a block diagram illustrating an upper layer image encoding apparatus 100b according to an embodiment of the present invention. to be. The output of the lower layer image encoding apparatus 100a and the output of the higher layer image encoding apparatus 100b may be connected to a multiplexer so that the bit streams of the plurality of layers may be combined into one bit stream. The video encoding apparatus according to another embodiment of the present invention may be configured with a lower layer image encoding apparatus 100a and a plurality of higher layer image encoding apparatuses 100b according to a selection, and in some cases, a plurality of lower layer image encoding apparatuses. 100a and a plurality of higher layer video encoding apparatuses 100b.

Referring to FIG. 1A, the lower layer image encoding apparatus 100a may include a motion predictor 111a, a motion compensator 112a, an intra predictor 120a, a switch 115a, a subtractor 125a, and a transformer 130a. ), A quantization unit 140a, an entropy encoding unit 150a, an inverse quantization unit 160a, an inverse transform unit 170a, an adder 175a, a filter unit 180a, and a reference picture buffer 190a.

The lower layer image encoding apparatus 100a may encode the lower layer input image in an intra mode or an inter mode and output a lower layer bitstream. Intra prediction means intra prediction and inter prediction means inter prediction. In the intra mode, the switch 115a may be switched to intra, and in the inter mode, the switch 115a may be switched to inter. The lower layer image encoding apparatus 100a may generate a prediction block for an input block of the lower layer input image and then encode a residual between the input block and the prediction block.

In the intra mode, the intra predictor 120a may generate a prediction block by performing spatial prediction using pixel values of blocks that are already encoded around the current block. The intra prediction unit may transmit or receive intra prediction mode information to another layer. The intra prediction unit 120a included in the lower layer image encoding apparatus 100a selectively receives the intra prediction mode information of the lower layer block according to a request of the intra prediction unit 120b of the higher layer image encoding apparatus 100b. It may be delivered to the intra predictor 120b of the image encoding apparatus 100b (ⓐ). In response to this, referring to FIG. 1B illustrating the higher layer image encoding apparatus 100b, the intra prediction unit 120b of the higher layer image encoding apparatus 100b may request an intra prediction of the lower layer image encoding apparatus 100a. The intra prediction mode information transmitted from the unit 120a may be received (ⓐ), and a prediction block may be generated using this information.

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

The subtractor 125a may generate a residual block by the difference between the input block and the generated prediction block. The transformer 130a may output a transform coefficient by performing a transform on the residual block. The quantization unit 140a may output the quantized coefficient by quantizing the input transform coefficient according to the quantization parameter.

The entropy encoder 150a performs lower entropy encoding by performing entropy encoding based on values (eg, quantized coefficients) calculated in the quantization unit 140a and / or encoding parameter values calculated in the encoding process. A bit stream can be output.

When entropy encoding is applied, a small number of bits are assigned to a symbol having a high probability of occurrence and a large number of bits are assigned to a symbol having a low probability of occurrence, thereby representing bits for encoding symbols. The size of the heat can be reduced. Therefore, compression performance of image encoding may be increased through entropy encoding. The entropy encoder 150a may use an encoding method such as exponential golomb, context-adaptive variable length coding (CAVLC), or context-adaptive binary arithmetic coding (CABAC) for entropy encoding.

Since the lower layer image encoding apparatus according to the embodiment of FIG. 1A performs inter prediction encoding, that is, inter-frame prediction encoding, the current encoded image needs to be decoded and stored to be used as a reference image. Accordingly, the quantized coefficient is inversely quantized by the inverse quantizer 160a and inversely transformed by the inverse transformer 170a. The inverse quantized and inverse transformed coefficients are added to the prediction block through the adder 175a to generate a reconstruction block.

The reconstruction block passes through the filter unit 180a, and the filter unit 180a applies at least one or more of a deblocking filter, a sample adaptive offset (SAO), and an adaptive loop filter (ALF) to the reconstruction block or the reconstruction picture. can do. The filter unit 180a may be called an adaptive in-loop filter. The deblocking filter may remove block distortion and / or blocking artifacts that occur at the boundaries between blocks. SAO can add an appropriate offset to the pixel value to compensate for coding errors. The ALF may perform filtering based on a value obtained by comparing the reconstructed image with the original image, and may be performed only when high efficiency is applied. The reconstructed block that has passed through the filter unit 180a may be stored in the reference picture buffer 190a.

Referring to FIG. 1B, the image encoding apparatus 100b of the upper layer includes a motion predictor 111b, a motion compensator 112b, and an intra, which correspond to the image encoding apparatus 100a of the lower layer illustrated in FIG. 1. Predictor 120b, Switch 115b, Subtractor 125b, Transformer 130b, Quantizer 140b, Entropy Encoder 150b, Inverse Quantizer 160b, Inverse Transformer 170b, Adder ( 175b), a filter unit 180b, and a reference picture buffer 190b, and each component functions to correspond to each corresponding component of the image encoding apparatus 100a of the lower layer.

The higher layer image encoding apparatus 100b may encode the higher layer input image in an intra mode or an inter mode and output a higher layer bitstream. The higher layer image encoding apparatus 100b may generate a prediction block for an input block of the higher layer input image and then encode a residual between the input block and the prediction block.

The intra predictor 120b may selectively request the information of the intra prediction mode from the intra predictor 120a of the lower layer image encoding apparatus 100a, and the intra prediction of the lower layer image encoding apparatus 100a may be requested according to the request. The intra prediction mode information transmitted from the unit 120a may be received (ⓐ), and a prediction block may be generated using this information.

Alternatively, although not shown in FIG. 1B, the intra predictor 120b of the higher layer image encoding apparatus 100b may be the same as the intra predictor 120a of the lower layer image decoding apparatus 100a of FIG. 1A. The intra prediction mode information of the encoded higher layer block may be transmitted to the intra predictor of the another higher layer image encoding apparatus according to a request of the intra predictor of another higher layer image encoding apparatus.

The entropy encoder 150b performs entropy encoding based on values (eg, quantized coefficients) calculated in the quantization unit 140b and / or encoding parameter values calculated in the encoding process, thereby performing higher layer bits. A bit stream can be output.

2A and 2B are block diagrams illustrating a configuration of an image decoding apparatus according to an embodiment of the present invention. An image decoding apparatus according to an embodiment of the present invention may include a plurality of layers of image decoding apparatuses, and the hierarchical structure of the plurality of image decoding apparatuses may correspond to the hierarchical structure of the encoding apparatus.

FIG. 2A is a block diagram illustrating the lower layer image decoding apparatus 200a, and FIG. 2B is a block diagram illustrating the higher layer image decoding apparatus 200b.

The input of the lower layer image decoding apparatus 200a and the input of the upper layer image decoding apparatus 200b are connected to the output of the demultiplexer so that one input bit stream is divided into a plurality of bit streams through the demultiplexer. The separated bitstream may be input to an image decoder of a corresponding layer.

The video decoding apparatus according to another embodiment of the present invention may be composed of a lower layer image decoding apparatus 200a and a plurality of higher layer image decoding apparatuses 200b according to a selection, and in some cases, a plurality of lower layer image decoding apparatuses. 200a and a plurality of higher layer image decoding apparatuses 200b.

Referring to FIG. 2A, the lower layer image decoding apparatus 200a may include an entropy decoder 210a, an inverse quantizer 220a, an inverse transformer 230a, an intra predictor 240a, a motion compensator 250a, An adder 255a, a filter unit 260a, and a reference picture buffer 270a are included.

The lower layer image decoding apparatus 200a may receive the lower layer bitstream output from the encoder and separated through the demultiplexer, perform decoding in an intra mode or an inter mode, and output a reconstructed image, that is, a reconstructed image. In the intra mode, the switch may be switched to intra, and in the inter mode, the switch may be switched to inter. The lower layer image decoding apparatus 200a may obtain a residual block from the input lower layer bitstream, generate a prediction block, and then add the residual block and the prediction block to generate a reconstructed block, that is, a reconstruction block.

The entropy decoder 210a may entropy decode the input lower layer bitstream according to a probability distribution to generate symbols including symbols in the form of quantized coefficients. The entropy decoding method is similar to the entropy coding method described above.

When the entropy decoding method is applied, a small number of bits are allocated to a symbol having a high probability of occurrence and a large number of bits are allocated to a symbol having a low probability of occurrence, whereby the size of the bit string for each symbol is increased. Can be reduced. Therefore, the compression performance of image decoding can be improved through an entropy decoding method.

The quantized coefficients are inversely quantized by the inverse quantizer 220a and inversely transformed by the inverse transformer 230a, and a residual block may be generated as a result of the inverse quantization / inverse transformation of the quantized coefficients.

In the intra mode, the intra predictor 240a may generate a prediction block by performing spatial prediction using pixel values of blocks already decoded around the current block. The intra prediction unit may transmit or receive intra prediction mode information to another layer. The intra predictor 240a of the lower layer image decoding apparatus 200a may decode the intra prediction mode information of the decoded lower layer block according to a request of the intra predictor 240b of the higher layer image decoding apparatus 200b. The intra prediction unit 240b of the apparatus 200b transmits to the intra prediction unit 240b. Referring to FIG. 2B, which corresponds to the higher layer image decoding apparatus 200b, the intra prediction unit 240b may perform intra prediction of the lower layer image decoding apparatus 200a in response to a request of the higher layer image decoding apparatus 200b. The intra prediction mode information transmitted from the unit 240a may be received (ⓑ), and a prediction block may be generated using the prediction prediction mode information.

 In the inter mode, the motion compensator 250a may generate a prediction block by performing motion compensation using a reference image stored in the motion vector and the reference picture buffer 270a.

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

Referring to FIG. 2B, the higher layer image decoding apparatus 200b includes an entropy decoder 210b, an inverse quantizer 220b, an inverse transformer 230b, an intra predictor 240b, a motion compensator 250b, An adder 255a, a filter unit 260b, and a reference picture buffer 270b, each component corresponding to a configuration of the lower layer image decoding apparatus 200a, and each component corresponding to the lower layer image decoding apparatus 200a. ) Can perform a function corresponding to the configuration.

The higher layer image decoding apparatus 200b may receive an upper layer bitstream output from the encoder and separated through the demultiplexer, perform decoding in an intra mode or an inter mode, and output a reconstructed image, that is, a higher layer reconstructed image. The higher layer image decoding apparatus 200b may obtain a residual block from the input upper layer bitstream, generate a prediction block, and then add the residual block and the prediction block to generate a reconstructed block, that is, a reconstruction block.

The entropy decoder 210b may entropy decode the input higher layer bitstream according to a probability distribution to generate symbols including symbols in the form of quantized coefficients. The entropy decoding method is similar to the entropy coding method described above.

In the intra mode, the intra predictor 240b may generate a prediction block by performing spatial prediction using pixel values of blocks already decoded around the current block. The intra predictor 240b may receive intra prediction mode information of another layer and may transmit intra prediction mode information to another layer according to a selection. The intra predictor 240b of the higher layer image decoding apparatus 200b receives intra prediction mode information transmitted from the intra predictor 240a of the lower layer image decoding apparatus 200a according to a request (ⓑ). To generate a prediction block.

Alternatively, although not shown in FIG. 2B, the intra predictor 240b of the higher layer image decoding apparatus 200b may be decoded like the intra predictor 240a of the lower layer image decoding apparatus 200a of FIG. 2A. The intra prediction mode information of the higher layer block may be transmitted to the intra prediction unit of the another higher layer image decoding apparatus according to a request of the intra prediction unit of another higher layer image decoding apparatus.

Hereinafter, a block means a unit of image encoding and decoding. When encoding or decoding an image, a coding or decoding unit refers to a divided unit when an image is divided and encoded or decoded, so that a coding unit (block) (CU: Coding Unit or CB: Coding Block) and a prediction unit (block) are used. (PU: Prediction Unit or PB: Prediction Block), transform unit (block) (TU: Transform Unit or TB: Transform Block), and so on. One block may be further divided into smaller sub-blocks. In addition, in the present specification, "picture" may be replaced with "frame", "field" and / or "slice" according to the context, and this division may be easily performed by those skilled in the art. There will be. For example, P pictures, B pictures, and forward B pictures may be replaced with P slices, B slices, and forward B slices depending on the context.

3 is a flowchart of a multi-layer video encoding method according to an embodiment of the present invention. A multi-layer video encoding method according to an embodiment of the present invention will be described.

In the multi-layer video encoding method according to an embodiment of the present invention illustrated in FIG. 3, information of a lower layer block 410 is used when performing intra prediction encoding on an encoding target block 400 of an upper layer. . The upper layer may be an enhancement layer and the lower layer may be a base layer. The higher enhancement layer may use block information of the lower enhancement layer. In addition, the enhancement layer may always use the block information of the base layer. For example, when there is the enhancement layer 1, the enhancement layer 2, and the enhancement layer 3, the enhancement layer 1, the enhancement layer 2, and the enhancement layer 3 may use block information of the base layer.

In the multi-layer video encoding method according to an embodiment of the present invention, determining a block of a lower layer corresponding to an encoding target block 400 of an upper layer (S110) and intra prediction of the determined lower layer block 410. In operation S120, the encoding target block 400 is encoded using the mode.

Encoding the block 400 to be encoded (S120) is to encode the block to be encoded by using a conventional intra prediction method in a higher layer when a corresponding block in a lower layer is not available or is encoded by inter prediction. can do. Alternatively, in this case, the intra prediction mode of the corresponding block in the lower layer may be regarded as a predetermined intra prediction mode (for example, DC mode) set by the user and used for encoding the encoding target block according to the setting. Alternatively, according to a configuration, the lower layer block 410 may be performed only when the intra prediction mode is encoded.

In the encoding of the encoding target block 400 (S120), a prediction signal of the encoding target block 400 may be generated using the determined intra prediction mode of the lower layer block 410. Alternatively, the intra prediction mode of the lower layer block 410 may be used as a candidate probable mode (MPM) candidate mode of the prediction target blocks 400 and 400.

4 is a diagram illustrating a relationship between an encoding object block 400 and a block 410 of a lower layer corresponding to the encoding object block 400. 4 illustrates a block 400 to be encoded and a block 410 of a lower layer corresponding to the block 400 to be encoded.

A step (S110) of determining a block 410 of a lower layer corresponding to the encoding target block 400 of the higher layer will be described with reference to FIG. 4. By selecting a block including the sample position of the lower layer block 410 corresponding to the reference sample position of the encoding target block 400, the lower layer block 410 corresponding to the encoding target block 400 may be selected. . The intra prediction mode of the sample position of the lower layer block corresponding to the reference sample position of the encoding target block may be used as the intra prediction mode of the lower layer block. The reference sample position may use not only the internal sample positions 401 and 402 of the encoding target block 400 but also the sample positions 403 and 404 included in the neighboring blocks. Sample positions included in the peripheral block include the upper right sample position 403 and the lower right sample position 404. The reference sample positions of the encoding object block may use various positions as well as the positions mentioned in the above embodiment. When the size of the input image between layers is different, a scaling factor between input images may be reflected in obtaining a sample position of a reference layer corresponding to an enhancement layer. The size ratio between the input images may be determined according to the size ratio between the input images. For example, if the size of the input image between layers is the same, the size ratio may be '1'. If the width / length of the enhancement layer is twice as large as the size of the reference layer, the size ratio is “ May be 2 '.

The position 401 of (xP + 1, yP + 1) among the internal sample positions shown in FIG. 4 will be described in more detail by way of example. The reference sample position of the encoding target block 400 is (xP + 1, yP + 1). In this case, the corresponding sample positions (refX, refY) of the lower layer may be calculated as in Equation 1 below. The block including the calculated (refX, refY) samples is determined as a block corresponding to the encoding target block 400.

Equation 1

The (xP + 1, yP + 1) / Scaling Factor may mean dividing xP + 1 and yP + 1 by Scaling Factor, respectively. When the ratio of the size of the input image between the width and the height is different, the horizontal scaling factor and the vertical scaling factor may be different from each other.

In the encoding of the encoding target block 400 (S120), a prediction signal of the encoding target block 400 may be generated using the determined intra prediction mode of the lower layer block 410. Alternatively, the intra prediction mode of the lower layer block 410 may be used as a candidate probable mode (MPM) candidate mode of the prediction target block 400.

As described above, the step of encoding the encoding target block 400 (S120) may generate a prediction signal of the encoding target block 400 using the intra prediction mode of the corresponding lower layer block 410, or the corresponding lower layer. The intra prediction mode of the layer block 410 may be performed as a Most Probable Mode (MPM) candidate mode of the encoding target prediction block 400.

FIG. 5 is a diagram for generating a prediction signal of an encoding target block 400 using an intra prediction mode of a lower layer block 410. The encoding of the encoding target block 400 by generating the prediction signal of the encoding object block 400 using the intra prediction mode of the lower layer block 410 will be described with reference to FIG. 5.

FIG. 5 illustrates a case where the intra prediction mode of the corresponding lower layer block 410 is vertical prediction. Referring to FIG. 5, when the intra prediction mode of the lower layer block 410 is vertical prediction, generating a prediction signal of the encoding target block 400 will be described.

First, a prediction signal is determined from peripheral reconstruction reference samples of the encoding object block 400 using only vertical prediction, which is an intra prediction mode of a lower layer block, among predetermined intra prediction modes. Next, transform, quantization, and entropy encoding are performed on the difference signal between the original signal of the encoding target block 400 and the prediction signal generated in the intra prediction mode of the lower layer block 410. Lastly, the decoding apparatus 200 indicates a flag indicating that the prediction signal of the encoding target block 400 is generated using the intra prediction mode of the lower layer block 410 in addition to the transformed and quantized difference signal (for example, base_intra_mode_flag). ). The size of this flag may be 1 bit. In the case where the target block is intra prediction coded as described above, transmission of MPM related syntax information (prev_intra_lum_pred_flag, mpm_idx, rem_intra_luma_pred_mod) used for normal intra prediction mode encoding may be omitted. For example, when the value of base_intra_mode_flag is '1', the decoding apparatus 200 uses only the “vertical direction” prediction, which is an intra prediction mode of a lower layer block corresponding to the position of a decoding target block, to encode with the encoding apparatus 100. The same prediction signal can be generated.

6 to 10 show that the optimal intra prediction mode of the encoding target block 400 is encoded by using the intra prediction mode of the corresponding lower layer block 410 as the Most Probable Mode (MPM) candidate mode of the encoding target block 400. It is a figure which shows that. 6 to 10, the encoding target block 400, the lower layer block 410 corresponding to the encoding target block 400, the left peripheral blocks 430 of the encoding target block 400, and the encoding target block 400 are illustrated. The top peripheral blocks 440 of the are shown. Among the neighboring blocks used in the MPM candidate mode of the encoding target block 400, a block that can use information of the corresponding block is represented by a block without a pattern, and a block that cannot be used is represented by a block having an oblique line. As an example, FIG. 7 illustrates a block 440 that can use information of a corresponding block and a block 430 that cannot use information.

When the intra prediction mode of the lower layer blocks 410 is used as the MPM candidate mode of the encoding target blocks 400, the encoding apparatus 100 transmits a flag to the decoding apparatus 200 to perform the same process in the decoding apparatus. It is possible to decode the intra prediction mode of the block. For example, the encoding apparatus 100 may designate a 1-bit size flag indicating that an intra prediction mode of the lower layer block may be used as an MPM candidate mode of the encoding target block 400. A picture paramter set), a slice segment, a coding unit, or a prediction unit may be transmitted to the decoding apparatus 200 so that the decoding apparatus 200 may decode an intra prediction mode of a corresponding block in response to an encoding process. .

The encoding apparatus 100 obtains an optimal prediction mode for the block to be encoded 400 from among predetermined intra prediction modes, and then encodes the optimal prediction mode using the selected MPM candidate mode.

A method of encoding the optimal prediction mode by the encoding apparatus 100 will be described. The encoding apparatus 100 decodes a flag prev_intra_luma_pred_flag indicating whether the calculated optimal prediction mode matches the MPM candidate mode, and index information mpm_idx indicating which candidate mode among the MPM candidates the calculated optimal prediction mode matches. To send). If the calculated optimal prediction mode does not match any of the MPM candidates, the encoding apparatus 100 transmits by designating '0' to a flag (prev_intra_luma_pred_flag) indicating whether the calculated optimal prediction mode matches the MPM candidate mode and presently. Directly encode the best prediction mode (rem_intra_luma_pred_mod) of the block

Hereinafter, a method of configuring the MPM candidate mode will be described with reference to FIGS. 6 to 10. FIG. 6 illustrates a case in which all of the information of the neighboring blocks 430 and 440 of the encoding target block 400 cannot be used. In the following description, the number of modes included in the MPM candidate mode may be fixed to two, three, four, and the like. When the modes are not filled, the specific mode may be used as an additional candidate mode. For example, if the number of modes included in the MPM mode candidate is three, and if candidate mode 1 and candidate mode 2 are different, candidate mode 3 does not belong to candidate mode 1 and candidate mode 2 in the planar / DC / Vertical mode sequence. DC mode can be used. At this time, the order of the mode for adding candidate mode 3 may have a different order from that of Planar / DC / Vertical, and may include other modes other than Planar / DC / Vertical.

If candidate mode 1 and candidate mode 2 are the same, if candidate modes 1 and 2 are DC or planar mode, candidate mode 1 may be used as planar mode, and candidate mode 2 may be used as DC and candidate mode 3 as vertical mode. If candidate mode 1 and candidate mode 2 are the same, and candidate modes 1 and 2 are not DC or planar mode, one mode smaller in sequence is selected based on candidate mode 1 or 2, and one mode larger than candidate mode 2 and one larger in sequence. Can be used as candidate mode 3.

When the number of modes included in the MPM mode candidate is four, the operation may be performed in a similar manner to the three cases. For example, the priority of the mode for determining candidates 3 or 4 may be in the order of Planar / DC / Horizontal / Vertical, as described above, the priority may be changed, and the modes included in the priority may be changed. In addition, the order between the candidate modes may be changed.

An example of using the intra prediction mode of the lower layer block 410 corresponding to the encoding target block 400 as the MPM candidate mode when all information on the neighboring blocks of the encoding target block 400 is not available will be described with reference to FIG. 6. Explain.

When the information of the neighboring blocks of the encoding target block 400 is not available as shown in FIG. 6, the encoding target block 400 is located at a picture boundary, a slice boundary, or a tile boundary to use information of the neighboring blocks. For example, the case where the neighboring block is encoded by inter prediction and the neighboring information is not available and the neighboring block have the same intra prediction mode may be mentioned. In this case, the intra prediction mode of the lower layer block 410 may be used as the MPM candidate mode.

In this case, when the information of the left neighboring block 430 and the upper neighboring block 440 used as the MPM candidate mode of the encoding target block 400 is not available, a specific mode is selected among predetermined intra prediction modes. In addition, the intra prediction mode of the lower layer block 410 may be used as an MPM candidate mode. For example, a planar mode among predetermined intra prediction modes may be used as the MPM candidate 1, and a horizontal mode, which is an intra prediction mode of the lower layer block 410, may be used as the MPM candidate 2. Alternatively, the DC mode among the prediction modes may be used as the MPM candidate mode 1, and the horizontal mode, which is an intra prediction mode of the lower layer block 410, may be used as the MPM candidate mode 2.

FIG. 7 is a diagram illustrating a case in which information of the left neighboring block 430 used in the MPM candidate mode of the encoding target block 400 is not available. When only information on one of the neighboring blocks of the left neighboring block 430 or the upper neighboring block 440 is available with reference to FIG. 7, the available left or upper intra prediction mode and the lower layer block 410 may be used. An example of using the intra prediction mode as the MPM candidate mode will be described.

In the embodiment illustrated in FIG. 7, only information of the upper peripheral block 440 of the encoding target block 400 may be used. The upper prediction mode of the leftmost block 441 of the upper peripheral block 440 and the intra prediction mode of the lower layer block 410 may be used as the MPM candidate mode. For example, the upper prediction mode of the leftmost block 441 of the upper peripheral block 440 may be used as the MPM candidate mode 1, and the intra prediction mode of the lower layer block 410 may be used as the MPM candidate mode 2. If the intra prediction mode of the leftmost block 441 of the upper neighboring block 440 is horizontal mode, and the intra prediction mode obtained from the lower layer block 410 is the vertical mode, MPM candidate mode 1 is horizontal mode and MPM candidate mode 2 is It may be in a vertical mode.

In another embodiment, when the information of the upper neighboring block 440 is not available and the information of the left neighboring block 430 is available, the intra prediction mode of the left neighboring block 430 and the lower layer block 410 is changed. Can be used in MPM candidate mode. In this case, the upper prediction mode of the upper peripheral block 440 and the intra prediction mode of the lower layer block 410 may be performed in the same manner as the MPM candidate mode.

FIG. 8 is a diagram illustrating a case where information of the uppermost block 431 of the left neighboring block 430 and the rightmost block 441 of the upper neighboring block 440 that is used as the MPM information of the encoding target block 400 is the same. to be. When the left neighboring block 430 and the upper neighboring block 440 that are used as the MPM information of the encoding target block 400 are the same, intra prediction of either the left neighboring block 430 or the upper neighboring block 440 is performed. The mode and the intra prediction mode of the lower layer block 410 may be used as the MPM candidate mode.

For example, the intra prediction mode of the uppermost block 431 of the left neighboring block 430 and the leftmost block 441 of the upper neighboring block 440 has a horizontal mode as a value. Hereinafter, it is assumed that the intra prediction mode of the left neighboring block 430 is obtained from the uppermost block 431, and the intra prediction mode of the upper neighboring block 440 is obtained from the leftmost block 441.

The intra prediction mode of the lower layer block 410 is a vertical mode. In this case, the horizontal mode, which is the intra prediction mode of the upper peripheral block 440, may be set as MPM candidate mode 1, and the vertical mode, which is the intra prediction mode of the lower layer block 410, may be set as MPM candidate mode 2. Similarly, a method of determining the value of the left neighboring block 430 as the MPM candidate mode 1 may also be considered.

Meanwhile, when the intra prediction mode of the lower layer block 410 has the same value as the intra prediction mode of the upper neighboring block 440 or the intra prediction mode of the left neighboring block 430, the intra prediction obtained from the lower layer block 410. Mode information may not be used. In this case, the MPM candidate mode may use the intra prediction modes of the upper neighboring block 440 and the left neighboring block 430 as MPM candidate mode 1 and MPM candidate mode 2 and may not use information of the lower layer block. The mode of the neighboring block having the same mode as the intra prediction mode of the lower layer block may be used as the MPM candidate mode 2. In addition, according to the selection, it may indicate that the intra prediction mode of the lower layer block is not used as the MPM candidate mode of the encoding target block 400.

FIG. 9 is a diagram illustrating a case where the values of the intra prediction modes of the upper peripheral block 440 and the left peripheral block 430 of the encoding target block 400 are different. A method of determining an MPM candidate mode by replacing at least one of the MPM candidates obtained from the upper neighboring block 440 and the left neighboring block 430 with the intra prediction mode obtained from the lower layer block 410 will now be described. .

In the inter-layer prediction method of an image signal according to an embodiment of the present invention, one of the MPM candidates obtained from the neighboring blocks of the encoding target block 400 may be replaced with the intra prediction mode obtained from the lower layer block 410.

In the embodiment of FIG. 9, the intra prediction mode of the upper peripheral block 440 of the encoding target block 400 is the horizontal mode, and the intra prediction mode of the left peripheral block 430 is the DC mode. The intra prediction mode of the lower layer block 410 of the encoding target block 400 is a vertical mode.

In the embodiment of FIG. 9, the horizontal mode, which is an intra prediction mode of the upper peripheral block 440, from the periphery of the encoding target block 400 to MPM candidate mode 1, and the DC mode that is the intra prediction mode of the left peripheral block 430. MPM candidate mode 2 can be used to determine the MPM candidate mode. In this case, candidate mode 2 may be replaced with a vertical mode which is an intra prediction mode of the lower layer block 410. That is, MPM candidate mode 1 may have a horizontal mode and MPM candidate mode 2 may have a vertical mode.

FIG. 10 is a diagram illustrating a case where the values of the intra prediction modes of the upper peripheral block 440 and the left peripheral block 430 of the encoding target block 400 are different. A step of using the intra prediction mode obtained from the lower layer block 410 as an additional MPM mode will be described with reference to FIG. 10.

The inter-layer prediction method of an image signal according to an embodiment of the present invention may use the intra prediction mode obtained from the lower layer block 410 as an additional MPM mode. Accordingly, the MPM candidate mode obtained from the lower layer block 410 may be added to the MPM candidate mode obtained from the neighboring block of the encoding target block 400.

In the embodiment of FIG. 10, the intra prediction mode of the upper peripheral block 440 of the encoding target block 400 is the horizontal mode, and the intra prediction mode of the left peripheral block 430 is the VER-8 mode. The intra prediction mode of the lower layer block 410 of the encoding target block 400 is a vertical mode.

In the embodiment of FIG. 10, the horizontal mode, which is an intra prediction mode of the upper peripheral block 440, from the periphery of the encoding target block 400 to MPM candidate mode 1, and the VER-8 that is the intra prediction mode of the left peripheral block 430. The MPM candidate mode can be determined by setting the mode to MPM candidate mode 2. FIG. In this case, the vertical mode, which is an intra prediction mode of the lower layer block 410, may be added as the MPM candidate mode 3. That is, the MPM candidate mode for the encoding target block 400 is composed of three candidate modes, MPM candidate mode 1 has a horizontal mode, MPM candidate mode 2 has a VER-8 mode, and MPM candidate mode 3 has a vertical mode. Have

11 is a flowchart of a multi-layer video decoding method according to an embodiment of the present invention. Hereinafter, a multi-layer video decoding method according to an embodiment of the present invention will be described.

The multi-layer video decoding method according to an embodiment of the present invention illustrated in FIG. 11 uses information of a lower layer block 410 in performing intra prediction encoding on a decoding target block of an upper layer. In the multi-layer video decoding method according to an embodiment of the present invention, it is determined whether the decoding target block is encoded using the intra prediction mode of the lower layer (S210) and the lower layer block 410 corresponding to the decoding target block. Decoding a block to be decoded using the intra prediction mode (S220).

Decoding the decoding object block by using the intra prediction mode of the lower layer block 410 corresponding to the decoding object block (S220), using the intra prediction mode of the corresponding lower layer block 410 to predict the decoding object block. This can be done by generating a signal. Alternatively, the intra prediction mode of the corresponding lower layer block 410 may be used as the Most Probable Mode (MPM) candidate mode of the current decoding target prediction block.

A step (S210) of determining whether the decoding object block is encoded using the intra prediction mode of the lower layer block 410 will be described. The intra prediction unit 240 of the decoding apparatus 200 may determine whether the decoding target block is encoded using the intra prediction mode of the lower layer block 410, and whether the decoding target block uses the intra prediction mode of the lower layer. Can be judged through

That is, the decoding apparatus 200 parses a flag that determines whether the decoding target block uses the intra prediction mode of the lower layer block 410 corresponding to the decoding target block, so that the decoding target block is the lower layer block 410. It can be determined whether the information is encoded using the information of.

In an embodiment of the present invention, the decoding apparatus 200 parses, for example, base_intra_mode_flag transmitted by the encoding apparatus 100 so that the decoding target block uses intra information of the lower layer block 410 in the screen. It may be determined whether the prediction is coded. At this time, if the corresponding flag value is '1', it may be determined that the decoding target block is intra prediction coded using the intra prediction mode of the lower layer block 410. If the corresponding flag value is '0', the lower layer block ( It may be determined that intra prediction coding is performed without using the intra prediction mode of 410. In this case, additional flags (prev_intra_luma_pred_flag, mpm_idx, and rem_intra_luma_pred_mod) indicating the intra prediction mode may be parsed. In an embodiment of the present invention, the decoding apparatus 200 determines, for example, the MPM candidate mode of the decoding target block by parsing base_intra_mode_prediction_flag transmitted by the encoding apparatus 100 through an SPS, a PPS, a slice segment, or the like. When the intra prediction mode of the lower layer block is used, it may be determined. In this case, if the corresponding flag value is '1', it may be determined that the decoding target block has determined the MPM candidate mode using the intra prediction mode of the lower layer block 410, and if the corresponding flag value is '0', the lower layer block It may be determined that the MPM candidate mode is determined from the left block and the upper block of the current decoding target block without using the intra prediction mode of 410.

Decoding the decoding object block using the intra prediction mode of the lower layer block 410 corresponding to the decoding object block (S220). Prediction of the decoding object block using the intra prediction mode of the corresponding lower layer block 410. Describe the process performed by generating a signal.

For example, when the encoding apparatus 100 transmits a base_intra_mode_flag value of 1, that is, a flag indicating that the prediction signal of the decoding object block 400 is generated using the intra prediction mode of the lower layer block 410 is 1. In this case, the decoding apparatus 200 determines that the decoding target block is to decode by using the intra prediction mode of the lower layer to generate the prediction signal of the decoding target block 400. The decoding apparatus 200 may generate the prediction signal of the current decoding target block using the intra prediction mode of the lower layer block 410 corresponding to the decoding target block. The process of obtaining the lower layer block 410 corresponding to the decoding apparatus 200 and generating the prediction signal of the current decoding target block using the intra prediction mode may be performed by the encoding apparatus 100 corresponding to the encoding target block 400. The lower layer block 410 is determined and the intra prediction signal of the encoding target block 400 is generated using the determined intra mode of the lower layer block 410.

The decoding apparatus 200 may select a block of the lower layer corresponding to the decoding object block by selecting a block including the sample position of the lower layer block 410 corresponding to the reference sample position of the decoding object block. As in the encoding apparatus 100, a scaling factor between input images may be reflected. In addition, the decoding apparatus 200 generates the prediction signal of the decoding object block by using the intra prediction mode of the corresponding lower layer block 410. Next, the decoding apparatus 200 generates a reconstruction signal of the current target block by adding the generated prediction signal and the difference signal transmitted and reconstructed by the encoding apparatus 100.

Lastly, the intra prediction of the lower layer block 410 to which the decoding apparatus 200 corresponds in step S220 of decoding the decoding object block using the intra prediction mode of the lower layer block 410 corresponding to the decoding object block. A process of decoding a decoding object block using a mode as a Most Probable Mode (MPM) candidate mode of a current decoding object prediction block will be described.

The decoding apparatus 200 has a value of 1, i.e., if the flag indicating that the intra prediction mode of the lower layer block 410 is used as the MPM candidate mode of the encoding target block 400 has a value of 1, for example, When the, base_intra_mode_prediction_flag) flag has a value of 1, the decoding apparatus 200 determines that the decoding target block has decoded the intra prediction mode of the lower layer block 410 using the MPM candidate mode.

Obtaining the corresponding lower layer block 410 may use the method as described above. In addition, the process of generating the MPM candidate mode of the decoding object block may be performed in correspondence with the process of generating the MPM candidate mode in the encoding apparatus 100.

For example, if the intra mode is not available from the left neighboring block 430 and the upper neighboring block 440 of the decoding target block, the predetermined intra prediction mode is used as the MPM candidate mode 1 and the corresponding lower layer block 410 is used. Intra prediction mode of may be used as MPM candidate mode 2.

In addition, when only intra mode information of one of the left neighboring block 430 and the upper neighboring block 440 of the decoding target block is available, the intra mode information of the available neighboring block is used as the MPM candidate mode 1 and corresponds. The intra prediction mode of the lower layer block 410 may be used as the MPM candidate mode 2.

In addition, when intra mode information is available from the left neighboring block 430 and the upper neighboring block 440 of the decoding target block, an intra mode having a smaller mode number is used as the MPM candidate mode 1 among the two intra modes. The intra prediction mode of the lower layer block 410 may be used by replacing the intra information of the neighboring block with the MPM candidate mode 2. Alternatively, the two intra modes are used as MPM candidate mode 1, the other intra mode is used as MPM candidate mode 2, and the intra prediction mode of the corresponding lower layer block 410 is additionally used as MPM candidate mode 3. It may be. In addition, in case of three or four modes included in the MPM candidate mode, additional candidates may be generated and used according to a predetermined rule.

 After generating the MPM candidate mode, it is determined which of the MPM candidates is the best prediction mode using the value of the flag (prev_intra_luma_pred_flag) indicating whether the best prediction mode matches the MPM candidate. When the value of prev_intra_luma_pred_flag is '1', index information (mpm_idx) indicating which candidate among MPM candidates matches may be parsed to obtain an optimal prediction mode among MPM candidate modes. If the value of prev_intra_luma_pred_flag is '0', the optimal prediction mode may be obtained by decoding rem_intra_luma_pred_mod.

In the above-described embodiment, the image in which the first layer and the second layer exist are described as an example, but the same method may be applied to more layers. Combinations of the above-described embodiments are not limited to the above-described embodiments, and various forms of combinations as well as the above-described embodiments may be provided according to implementation and / or need.

In the above-described embodiments, the methods are described based on a flowchart as a series of steps or blocks, but the present invention is not limited to the order of steps, and any steps may occur in a different order or at the same time than the other steps described above. Can be. Also, one of ordinary skill in the art would appreciate that the steps shown in the flowcharts are not exclusive, that other steps may be included, or that one or more steps in the flowcharts may be deleted without affecting the scope of the present invention. I can understand.

The foregoing embodiments include examples of various aspects. Although not all possible combinations may be described to represent the various aspects, one of ordinary skill in the art will recognize that other combinations are possible. Accordingly, it is intended that the present invention cover all other replacements, modifications and variations that fall within the scope of the following claims.

Claims (20)

A multi-layer video encoding method comprising a first layer including a current encoding target block and a second layer which is a lower layer of the first layer, Determining a corresponding block in the second layer corresponding to the encoding target block; And And encoding the encoding target block by using an intra prediction mode of the corresponding block in the second layer. The method of claim 1, wherein the encoding of the encoding target block comprises: And a prediction signal of the encoding target block is generated using an intra prediction mode of the corresponding block in the second layer. The method of claim 1, wherein the encoding of the encoding target block comprises: And using the intra prediction mode of the corresponding block in the second layer as a Most Probable Mode (MPM) candidate mode of the encoding target block. A multi-layer video decoding method comprising a first layer including a current decoding target block and a second layer which is a lower layer of the first layer, And decoding the decoding object block using the intra prediction mode of the second layer block. 5. The method of claim 4, wherein the multi-layer video decoding method specifies a sample position of the second layer corresponding to a reference sample position of the decoding target block using a size ratio between input images. The multi-layer video decoding method characterized in that it specifies. The method of claim 4, wherein the decoding of the decoding object block comprises: Determining whether the decoding object block used the intra prediction mode of the second layer block; In the decoding step, when the decoding object block uses the intra prediction mode of the second layer, the decoding object block is decoded using the intra prediction mode of the second layer. The method of claim 4, wherein the decoding of the decoding object block comprises: And generating a prediction signal of the decoding target block using the intra prediction mode of the second layer block. The method of claim 4, wherein the decoding of the decoding object block comprises: And using an intra prediction mode of the second layer block as a Most Probable Mode (MPM) candidate mode of the decoding target block. The method of claim 8, wherein the decoding of the decoding object block comprises: At least one of the intra mode of the upper neighboring block or the left neighboring block is replaced with the intra prediction mode of the second layer block. The method of claim 8, wherein the decoding of the decoding object block comprises: The intra decoding mode of the upper neighboring block and the left neighboring block of the decoding target block and the intra prediction mode of the second layer block are used as the MPM candidate mode. A computer-readable recording medium having recorded thereon a program for executing the method of any one of claims 1 to 10. A multi-layer video encoding apparatus including a first layer including a current encoding target block and a second layer which is a lower layer of the first layer, And an intra predictor for encoding the encoding target block using the intra prediction mode of the second hierarchical block. The apparatus of claim 12, wherein the intra prediction unit generates a prediction signal of the encoding target block by using an intra prediction mode of the second layer block. The multi-layer video encoding apparatus of claim 12, wherein the intra estimator uses an intra prediction mode of the second layer block as a Most Probable Mode (MPM) candidate mode of the encoding target block. A multi-layer video decoding apparatus including a first layer including a current decoding target block and a second layer which is a lower layer of the first layer, And an intra predictor for decoding the decoding object block using an intra prediction mode of a second layer block. The second layer block corresponding to the decoding object block according to claim 15, wherein the intra prediction unit specifies a sample position of the second layer corresponding to a reference sample position of the decoding object block using a size ratio between input images. Multi-layer video decoding apparatus characterized in that it specifies. The apparatus of claim 15, wherein the intra predictor generates a prediction signal of the decoding target block using an intra prediction mode of the second layer block. The apparatus of claim 15, wherein the intra prediction unit uses an intra prediction mode of the second layer block as a candidate probable mode (MPM) candidate mode of the decoding target block. The multi-layer video of claim 18, wherein the intra prediction unit replaces at least one of an intra mode of an upper neighboring block or a left neighboring block of the decoding target block with an intra prediction mode of the second layer block. Decryption device. 19. The multi-layer video of claim 18, wherein the intra predictor uses an intra mode of an upper neighbor block and a left neighbor block of the decoding target block and an intra prediction mode of the second layer block as an MPM candidate mode. Decryption device.

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