KR101561461B1 - Video encoding and decoding method and apparatus using the same - Google Patents

Abstract

A method of decoding an image supporting a plurality of layers includes decoding a reference block of a base layer that can be referred to by a target block of an upper layer to be decoded; Setting a merged motion prediction region of the target block based on the merged motion prediction region of the reference block; Deriving a merged motion prediction list for the target block based on the merged motion prediction region of the target block; And performing motion compensation on the target block based on the merged motion prediction list. There is provided a method of encoding / decoding an image, which can reset a merge estimated region when merge prediction is performed using information of another layer, and an apparatus using the same

Description

TECHNICAL FIELD [0001] The present invention relates to a video encoding / decoding method, and a video encoding /

The present invention relates to an image coding and decoding process, and more particularly, to a hierarchical image coding / decoding method and apparatus for providing parallelism in hierarchical video coding.

Recently, broadcasting service having high definition (HD) resolution has been expanded not only in domestic but also in the world, so that many users are accustomed to high definition and high definition video, and accordingly, many organizations are spurring development for next generation video equipment. In addition, with the increase of interest in UHD (Ultra High Definition) having resolution more than 4 times of HDTV in addition to HDTV, a compression technique for a higher resolution and a higher image quality is required.

An inter prediction technique for predicting a pixel value included in a current picture from temporally preceding and / or following pictures for image compression, a prediction method of predicting a pixel value included in a current picture using pixel information in the current picture An intra prediction technique, an entropy coding technique in which a short code is assigned to a symbol having a high appearance frequency and a long code is assigned to a symbol having a low appearance frequency.

There is a technique for providing a constant network bandwidth under a limited operating environment of hardware without considering a flexible network environment. However, a new compression technique is required in order to compress image data applied to a network environment in which the bandwidth varies from time to time, and a scalable video encoding / decoding method can be used for this purpose.

As a result, there is an increasing demand to efficiently transmit data to various terminals and various transmission environments by generating one integrated data capable of supporting various spatial resolutions and various frame rates have. As a video coding technology to support efficient transmission of such data, standardization of SHVC (SHVC: Scalable High Efficiency Video Coding) based on HEVC is underway. The image information of the upper layer in the SHVC can be encoded through the image information of the lower layer. Here, the lower layer may mean a base layer.

The present invention provides a method for providing synchronization and better parallelism of encoding / decoding time of each layer.

The present invention provides an image encoding / decoding method and an apparatus using the same that can reset a merge estimated region when performing merge prediction using information of another layer.

According to an embodiment of the present invention, when coding layers in the SHVC, the MER size in the upper layer is reset according to the MER size in the base layer, so that the encoding / decoding time of the base layer block and the encoding / A method for encoding / decoding an image that can reduce a difference in decoding time and an apparatus using the same.

According to an embodiment of the present invention, there is provided a method of decoding an image supporting a plurality of layers, the method comprising: decoding a reference block of a base layer that can be referred to by a target block of an upper layer to be decoded; Setting a merged motion prediction region of the target block based on the merged motion prediction region of the reference block; Deriving a merged motion prediction list for the target block based on the merged motion prediction region of the target block; And performing motion compensation on the target block based on the merged motion prediction list.

The merged motion prediction region of the target block may be set according to a ratio of a picture width of the base layer and a picture width of the upper measurement.

Wherein the merged motion prediction region of the target block is a predetermined level value indicating a merged motion prediction region of the reference block and a ratio of a picture width of the base layer to a picture width of the upper metric And a second ratio corresponding to a quotient obtained by dividing the first ratio by two.

Wherein a merged motion prediction region of the target block is a predetermined level value indicating a merged motion prediction region of the reference block and a ratio of a picture width of the base layer to a picture width of the upper metric The second ratio corresponding to a quotient obtained by dividing the reciprocal of the first ratio by two.

The level value may be derived through decoding of a syntax element log2_parallel_merge_level_minus2 for the base layer.

And receiving a predetermined syntax element indicating a merged motion prediction region of the target block.

The target block is a coding block divided into at least two prediction blocks, and a parallel merged motion list may be generated between prediction blocks included in the merged motion prediction area.

The merged motion prediction region of the target block may be set to a predetermined size according to whether the target block is a luminance block or a color difference block.

According to another aspect of the present invention, there is provided an apparatus for decoding an image supporting a plurality of layers, the apparatus comprising: a base layer decoding unit decoding a reference block of a base layer that can be referred to by a target block of an upper layer to be decoded; Setting a merged motion prediction region of the target block based on the merged motion prediction region of the reference block, deriving a merged motion prediction list for the target block based on the merged motion prediction region of the target block, And an upper layer decoding unit for performing motion compensation on the target block based on the prediction list.

The present invention is used to synchronize the encoding / decoding time of each layer in video coding.

According to an embodiment of the present invention, when the layers are encoded in the SHVC, the MER size in the upper layer is reset according to the MER size in the base layer, so that the coding / decoding time of the base layer block, A method of encoding / decoding an image capable of reducing a difference in decoding time, and an apparatus using the same.

1 is a block diagram showing a configuration of an image encoding apparatus according to an embodiment of the present invention.
2 is a block diagram illustrating a configuration of an image decoding apparatus according to an embodiment of the present invention.
3 is a conceptual diagram schematically showing an embodiment of a scalable video coding structure using a plurality of layers to which the present invention can be applied.
4 is a diagram illustrating neighboring blocks that may be included in the merged motion candidate list.
FIG. 5 shows an example of setting a merged motion candidate list when one CU is divided into two PUs (Nx2N).
6 is a diagram illustrating an example of a 2Nx2N CU including a plurality of CUs.
Fig. 7 is a diagram showing an embodiment for explaining a method for constructing a merged motion candidate list in parallel.
FIG. 8 is a block diagram illustrating a plurality of MERs according to an exemplary embodiment of the present invention. Referring to FIG.
9 is a diagram showing an example of a coding / decoding structure in SHVC.
10 is a diagram showing an example of the SHVC bitstream structure.
11 is a diagram showing an example of a method for realizing block-based parallel encoding / decoding.
FIG. 12 is a diagram showing an example of the actual parallel coding / decoding order between the upper layer and the base layer and the time difference therebetween.
FIG. 13 is a diagram illustrating an example of a difference in encoding / decoding time between one higher layer block and a corresponding base layer block.
FIG. 14 is a diagram illustrating an example of difference in encoding / decoding time between one higher layer image and a corresponding base layer image according to the inter-block coding / decoding time difference.
15 is a diagram illustrating an example of a method of coding / decoding a lower layer and a corresponding upper layer block in parallel.
16 is a diagram showing an example of an increase in coding / decoding time due to dependency between upper layer blocks.
FIG. 17 is a diagram illustrating an example in which the MER size of an upper layer and the MER size of a base layer are the same for blocks corresponding to layers. FIG.
18 is a diagram illustrating an example of an increase in coding / decoding time due to a dependency due to a difference in MER between an upper layer and a base layer.
19 is a diagram illustrating an example of coding / decoding time reduction by parallel coding / decoding of an upper layer block.
20 is a conceptual diagram of a time synchronization method according to an embodiment of the present invention.
FIG. 21 is a diagram illustrating an example of reduction in coding / decoding time due to MER size reset of an upper layer image.
22 is a control block diagram illustrating a structure of a decoder according to an embodiment of the present invention.
23 is a control block diagram illustrating a structure of a decoder according to another embodiment of the present invention.
24 is a block diagram illustrating a structure of an encoder according to an embodiment of the present invention.
25 is a block diagram illustrating a structure of an encoder according to another embodiment of the present invention.
26 is a diagram illustrating an example in which an image size of an upper layer is larger than an image size of a base layer according to the present invention.
27 is a diagram illustrating an example in which the image size of the upper layer is smaller than the image size of the base layer according to the present invention.
28 is a diagram illustrating an example of a control flowchart of an algorithm for determining an MER size of an upper layer according to an image proportional value of an upper layer and a base layer according to the present invention.
FIG. 29 is a diagram illustrating an embodiment for combining methods according to the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the following description of the embodiments of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present disclosure rather unclear.

It is to be understood that when an element is referred to as being "connected" or "connected" to another element, it may be directly connected or connected to the other element, . In addition, the description of "including" a specific configuration in the present invention does not exclude a configuration other than the configuration, and means that additional configurations can be included in the practice of the present invention or the technical scope of the present invention.

The terms first, second, etc. 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 a second component, and similarly, the second component may also be referred to as a first component.

In addition, the components shown in the embodiments of the present invention are shown independently to represent different characteristic functions, which does not mean that each component is composed of separate hardware or software constituent units. 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 separate embodiments of the components are also included within the scope of the present invention, unless they depart from the essence of the present invention.

In addition, some of the components are not essential components to perform essential functions in the present invention, but may be optional components only to improve 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.

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

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

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

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

In the inter mode, the motion predicting unit 111 may obtain a motion vector by searching an area of the reference image stored in the reference image buffer 190, which is best matched with the input block, in the motion estimation process. The motion compensation unit 112 may generate a prediction block by performing motion compensation using a motion vector and a reference image stored in the reference image buffer 190.

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

The entropy encoding unit 150 entropy-codes a symbol according to a probability distribution based on the values calculated by the quantization unit 140 or the encoding parameter value calculated in the encoding process to obtain a bit stream Can be output. The entropy coding method is a method of receiving symbols having various values and expressing them as decodable binary numbers while eliminating statistical redundancy.

Here, the symbol means a syntax element to be encoded / decoded, a coding parameter, a value of a residual signal, and the like. The encoding parameter is a parameter necessary for encoding and decoding. The encoding parameter may include information that can be inferred in an encoding or decoding process, as well as information encoded and encoded in a encoding device such as a syntax element, and may be encoded or decoded It means the information that is needed when doing. The coding parameters include, for example, values such as intra / inter prediction mode, motion / motion vector, reference picture index, coding block pattern, presence of residual signal, transform coefficient, quantized transform coefficient, quantization parameter, block size, Statistics can be included. In addition, the residual signal may mean a difference between the original signal and the prediction signal, or a signal in which the difference between the original signal and the prediction signal is transformed or a difference between the original signal and the prediction signal is transformed and the quantized signal . The residual signal can be regarded as a residual block in block units.

When entropy coding 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, so that the size of a bit string for the symbols to be coded Can be reduced. Therefore, the compression performance of the image encoding can be enhanced through the entropy encoding.

For entropy encoding, an encoding method such as exponential golomb, context-adaptive variable length coding (CAVLC), and context-adaptive binary arithmetic coding (CABAC) may be used. For example, a table for performing entropy encoding such as a variable length coding / code (VLC) table may be stored in the entropy encoding unit 150, and the entropy encoding unit 150 may store the stored variable length encoding (VLC) table for performing entropy encoding. Further, the entropy encoding unit 150 derives a binarization method of a target symbol and a probability model of a target symbol / bin, and then performs entropy encoding using the derived binarization method or probability model You may.

The quantized coefficients can be inversely quantized in the inverse quantization unit 160 and inversely transformed in the inverse transformation unit 170. The inverse quantized and inverse transformed coefficients can be added to the prediction block through the adder 175 and a reconstruction block can be generated.

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

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

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

The video decoding apparatus 200 receives the bit stream output from the encoding apparatus and decodes the video stream into the intra mode or the inter mode, and outputs the reconstructed video, that is, the reconstructed video. In the intra mode, the switch is switched to the intra mode, and in the inter mode, the switch can be switched to the inter mode. The video decoding apparatus 200 may generate a reconstructed block, i.e., a reconstructed block, by obtaining a reconstructed residual block from the input bitstream, generating a predicted block, and adding the reconstructed residual block to the predicted block.

The entropy decoding unit 210 may entropy-decode the input bitstream according to a probability distribution to generate symbols including a symbol of a quantized coefficient type. The entropy decoding method is a method of generating each symbol by receiving a binary sequence. The entropy decoding method is similar to the entropy encoding method described above.

The quantized coefficients are inversely quantized in the inverse quantization unit 220 and inversely transformed in the inverse transformation unit 230. As a result that the quantized coefficients are inversely quantized / inverse transformed, reconstructed residual blocks can be generated.

In the intra mode, the intraprediction unit 240 can generate a prediction block by performing spatial prediction using the pixel value of the already coded block around the current block. In the inter mode, the motion compensation unit 250 can generate a prediction block by performing motion compensation using a motion vector and a reference image stored in the reference image buffer 270. [

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

An entropy decoding unit 210, an inverse quantization unit 220, an inverse transform unit 230, an intra prediction unit 240, a motion compensation unit 250, a filter unit 260 included in the image decoding apparatus 200, An entropy decoding unit 210, an inverse quantization unit 220, an inverse transform unit 230, an intraprediction unit 240, a motion compensation unit 240, And the filter unit 260 may be expressed as a decoding unit or a decoding unit.

In addition, the video decoding apparatus 200 may further include a parsing unit (not shown) for parsing information related to the encoded video included in the bitstream. The parsing unit may include an entropy decoding unit 210 or may be included in the entropy decoding unit 210. Such a parsing unit may also be implemented as one component of the decoding unit.

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

In order to transmit video data, a transmission medium is required, and the performance of the transmission medium varies depending on various network environments. A scalable video coding method may be provided for application to these various transmission media or network environments.

The scalable video coding method is a coding method for enhancing the coding / decoding performance by eliminating inter-layer redundancy by utilizing texture information, motion information, residual signal, etc. between layers. The scalable video coding method can provide various scalabilities in terms of spatial, temporal, and image quality according to surrounding conditions such as a transmission bit rate, a transmission error rate, and a system resource.

Scalable video coding can be performed using multiple layers structure to provide a bitstream applicable to various network situations. For example, the scalable video coding structure may include a base layer that compresses and processes image data using a general image encoding method, and compresses and compresses the image data using the base layer encoding information and general image encoding method Lt; RTI ID = 0.0 > layer. ≪ / RTI >

Here, the layer may be classified into a video and a bit classified based on spatial (e.g., image size), temporal (e.g., coding order, image output order, frame rate), image quality, Means a set of bitstreams. In addition, the base layer may be a lower layer, a reference layer or a base layer, an enhancement layer may mean an enhancement layer, and an enhancement layer. The plurality of layers may also have dependencies between each other.

Referring to FIG. 3, for example, the base layer may be defined by a standard definition (SD), a frame rate of 15 Hz, a bit rate of 1 Mbps, and a first enhancement layer may be defined as high definition (HD), a frame rate of 30 Hz, And the second enhancement layer may be defined as 4K-UHE (ultra high definition), a frame rate of 60 Hz, and a bit rate of 27.2 Mbps. The format, the frame rate, the bit rate, and the like are one example, and can be determined as needed. Also, the number of layers to be used is not limited to the present embodiment, but can be otherwise determined depending on the situation.

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

In the case of coding and decoding of video supporting a plurality of layers in a bitstream, that is, scalable coding, there is a strong correlation between a plurality of layers. Therefore, if prediction is performed using this association, It is possible to eliminate the redundant elements and improve the image coding performance. Hereinafter, prediction of a current layer to be predicted using information of another layer is referred to as inter-layer prediction. Scalable video coding has the same meaning as scalable video coding in view of coding and scalable video decoding in view of decoding.

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

Generally, inter-picture prediction can be performed on a current block based on a reference picture, with at least one of a previous picture or a following picture of the current picture being a reference picture. An image used for prediction of a current block is referred to as a reference picture or a reference frame.

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

The inter picture 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 may generate a prediction block such that the residual signal with respect to the current block is minimized and the motion vector size is 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 encoder and the decoder can generate a predicted motion vector candidate list using a motion vector of a reconstructed neighboring block and / or a motion vector of a call block . That is, the motion vector of the reconstructed neighboring block and / or the motion vector of the call block may be used as a predicted motion vector candidate. The encoding apparatus may transmit to the decoding apparatus a predicted motion vector index indicating an optimal predicted motion vector selected from the predicted 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 predicted motion vector candidates included in the predicted motion vector candidate list using the predicted 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 that indicates a 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 the predictive block and the residual transmitted from 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 the skip flag, the merge flag, and the like received from the encoding apparatus on the motion information necessary for inter-prediction of the current block, for example, information on the motion vector, reference picture index,

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.

The merge motion prediction method, that is, the motion information used in the merge prediction is information including at least one of a motion vector, an index for a reference image, and a prediction direction (unidirectional, bidirectional, etc.). The prediction direction can be largely divided into unidirectional prediction and bidirectional prediction according to use of a reference picture list (Ref PictureList).

The unidirectional prediction is divided into forward prediction (Pred_L0) using the forward reference picture list (LIST0) and backward prediction (Pred_L1; Prediction L1) using the reverse reference picture list (LIST1).

Bidirectional prediction (Pred_BI) may use both the forward reference picture list (LIST 0) and the backward reference picture list (LIST 1), which means that both the forward prediction and the backward prediction exist.

Also, when there are two forward predictions by copying the forward reference picture list (LIST 0) to the reverse reference picture list (LIST 1), they may be included in the range of bidirectional prediction. Such prediction direction can be expressed using flag information such as predFlagL0, predFlagL1.

For example, in the case of unidirectional prediction and forward prediction, predFlagL0 may be '1' and predFlagL1 may be '0'. In case of unidirectional prediction and backward prediction, predFlagL0 may be '0' and predFlagL1 may be '1'. In case of bi-directional prediction, predFlagL0 may be '1' and predFlagL1 may be '1'.

The merged motion prediction may be performed by a coding unit (CU) or a prediction unit (PU).

In a case where a merge movement is performed for each CU or PU (a CU is referred to as an 'encoding block' for convenience of explanation, a PU can be expressed as' a block ', a CU and a PU may be collectively referred to as a' ) And merging motion with any of the neighboring blocks adjacent to the current block (the left adjacent block of the current block, the upper adjacent block of the current block, the temporal adjacent block of the current block, etc.) Should be signaled.

The merged motion candidate list represents a list in which motion information is stored, and is generated before the merged motion prediction is performed. The motion information stored in the merged motion candidate list may be motion information of a neighboring block adjacent to the current block or motion information of a collocated block corresponding to the current block in the reference image. Also, the motion information stored in the merged motion candidate list may be new motion information created by combining motion information already present in the merged motion candidate list.

4 is a diagram illustrating neighboring blocks that may be included in the merged motion candidate list.

It is determined whether or not the motion information of the corresponding block in the neighboring blocks A, B, C, D, and E and the candidate block H (or M) in the same position can be used for the merging motion prediction of the current block And when the specific block is available for the merged motion prediction, the motion information of the corresponding block may be added to the merged motion candidate list.

Also, if each neighboring block has the same motion information, the motion information of the neighboring block is not included in the merging motion candidate list.

For example, when generating a merged motion candidate list for an X block in FIG. 4, a neighboring block A is included in the merged motion candidate list after the neighboring block A is available. If the neighboring block B is not the same motion information as the neighboring block A Only candidate merging motion candidate list.

In the same way, the neighboring block C can be included in the merged motion candidate list only when it is not the same motion information as the neighboring block B. The same method can be applied to the peripheral block D and the peripheral block E.

Here, the same motion information may mean that the motion vector is the same and the same reference picture is used and the same prediction direction (unidirectional (forward, reverse), bidirectional) is used.

Finally, in FIG. 4, the merged motion candidate list for the X block may be added to the list in a predetermined order, for example, A → B → C → D → E → H (or M) block order. Here, A can be expressed as A1, B as B1, C as B0, D as A0, and E as B2. In this case, A → B → C → D → E → H (or M) → B1 → B0 → A0 → B2 → H (or M).

FIG. 5 shows an example of setting a merged motion candidate list when one CU is divided into two PUs (Nx2N).

The neighboring block for merged motion prediction may be motion information of a neighboring block adjacent to the current block or motion information of a collocated block corresponding to the current block in the reference image.

5A and 5B show neighboring blocks used for constructing the merged motion candidate list for the first PU (PU0) and the second PU (PU1), respectively.

The A1 block located in the first PU is not included in the merged motion candidate list of the second PU in order to construct the merged motion candidate list of the second PU shown in FIG. 5 in parallel. That is, the A1 block located in the first PU of (b) is not usable in the merged motion candidate list construction of the second PU, and the motion information of A1 block can not be accessed in the merging motion candidate list construction . Or, it may mean that there is no motion information for block A1, or it may mean that block motion information is not available.

6 is a diagram illustrating an example of a 2Nx2N CU including a plurality of CUs.

The first CU is not divided into PUs, the CUO of the second CU is divided into PUs of 2NxN, the CU0 of the third CU is divided into PUs of Nx2N, and the CU0 of the last CU is divided into PUs of NxN.

The encoder and the decoder construct a merged motion candidate list for the PU to perform coding / decoding on the motion information. In order to construct a merged motion candidate list, motion information about neighboring PUs must exist.

On the other hand, when the encoder performs merge estimation in parallel in the 2Nx2N CU including several CUs as shown in FIG. 6, the PU0 corresponding to the first PU among the PUs in the 2Nx2N CU Only Merge Estimation can be performed.

Other PUs can not perform Merge Estimation in parallel. The reason for this is that each PU should construct a merged motion candidate list and then perform merge estimation. In case of PU except PU0, there is no motion information about PUs of adjacent neighboring blocks, so a merged motion candidate list can be constructed none. Therefore, PU except PU0 can not perform merge estimation in parallel.

A parallel Merge Estimation (PME) method can be used to apply Merge Estimation to the PUs except for PU0 in FIG. 6 in parallel. An example of the method is shown in FIG. 7.

Fig. 7 is a diagram showing an embodiment for explaining a method for constructing a merged motion candidate list in parallel.

As shown, an LCU (largest coding block) is divided into a plurality of CUs, and one CU may be divided into one or more PUs. There are several blocks around the PU to be predicted, and the motion information for such blocks may or may not be available. That is, there are MVPs (motion vector predictions / motion vector precidictors) that are already coded / decoded, unavailable MVPs included in the same MER, and MVPs that are not yet used because surrounding PUs are not coded / decoded.

In the case of " PU0 " in FIG. 7, since motion information available in neighboring blocks already exists, a merged motion prediction list can be created.

In the case of " PU1 " in FIG. 7, since neighboring blocks are not coded (or decoded), there is no usable motion information, and the conventional method can not use the concurrent motion method in parallel. In this case, by not including the unusable motion information of the neighboring blocks in the merged motion candidate list, it is possible to make the merged motion prediction method usable in parallel. In other words, the merge motion candidate list can be configured in parallel by constructing the merged motion candidate list using only the motion information of the available neighbor blocks with respect to the current PU.

The permissible range of the parallel merged motion estimation (PME) method can be expressed as a merged estimation region (MER; merge prediction region). The LCU of Fig. 7 can be composed of four MERs.

For example, in the case of " PU2 " in FIG. 7, motion information of neighboring blocks existing in the same MER may not be included in the merged motion candidate list, and only motion information of neighboring blocks existing in another MER may be included in the merged motion candidate list .

FIG. 8 is a block diagram illustrating a plurality of MERs according to an exemplary embodiment of the present invention. Referring to FIG. As shown, the blocks are contained in a MER having a constant size.

Since the PME is performed only within the corresponding MER and coding / decoding is performed in parallel within the corresponding MER, the motion candidate included in the corresponding MER is marked as 'unavailable' and excluded from the candidate . That is, the motion candidates in the MER are not included in the motion candidate list.

9 is a diagram showing an example of a coding / decoding structure in SHVC.

As shown in FIG. 9, an image of Scalable High Efficiency Video Coding (SHVC) is composed of a base layer (B0, B1, B2, B3 ...) and a high-resolution (or high- (Enhanced Layer, E0, E1, E2, E3 ...). Of course, two or more of the above measurements are possible.

Referring to FIG. 9, a coding / decoding structure of Scalable High Efficiency Video Coding (SHVC) is a coding / decoding structure of a higher layer (or higher picture quality) after encoding / decoding of a base layer composed of the lowest resolution Enhanced Layer) is encoded / decoded. The arrows indicate the encoding / decoding order of the image.

However, when encoding / decoding is performed in this order, a delay occurs in units of one picture (Picture). This is because the base layer image corresponding to the higher layer image is used for prediction in order to encode / decode the image of the upper layer, and it is necessary to wait until all the base layer images are encoded / decoded.

10 is a diagram showing an example of the SHVC bitstream structure.

As shown in FIG. 6, in order to encode / decode an upper layer image, it is necessary to wait until all base layer images at the same time are encoded / decoded. However, as shown in FIG. 10, the bitstream can be divided into NAL units in units of NAL headers, so that the upper layer data and the base layer data can be distinguished from each other. Therefore, it is possible to separately code / decode each layer separately.

Therefore, the base layer image and the upper layer image can be encoded / decoded together in parallel, and it is possible to parallelly encode / decode corresponding blocks among the respective layers as one of such methods.

In this case, in order to encode / decode a block constituting an upper layer, a block of the corresponding base layer must be encoded / decoded first.

11 is a diagram showing an example of a method for realizing block-based parallel encoding / decoding.

As shown in FIG. 11, in order to encode / decode E0, B0 must be coded / decoded first. To encode / decode E1, B1 must be coded / decoded first. The coding / decoding order between the upper layer and the base layer is B0 - B1 (E0) - B2 (E1) - B3 (E2) - ... Respectively. Where the parentheses indicate that encoding / decoding is possible.

12 is a diagram illustrating an example of a sequence of actual parallel coding / decoding between an upper layer and a base layer and a time difference therebetween, and FIG. 13 is a diagram illustrating an example of a time difference between an upper layer block and a corresponding base layer block coding / And Fig.

In the parallel encoding / decoding in the SHVC, when the encoding / decoding of the base layer block starts first, encoding / decoding of the corresponding upper layer block proceeds.

More specifically, as shown in FIG. 12, a large amount of time difference occurs in encoding / decoding between a block of one base layer and a block of a corresponding upper layer. The block of each upper layer image generally has a width and a height corresponding to twice the height of the base layer block, and the coding / decoding of the base layer image block is performed through the process of increasing the number of encoding / A time delay of about 4 times or more than the time is generated. Therefore, the encoding / decoding of the higher layer image itself also has a time delay of about four times that of the base layer image.

FIG. 13 shows the coding / decoding time differences between the upper layer block and the lower layer block, FIG. 14 illustrates an encoding / decoding time difference between an upper layer image and a corresponding base layer image encoding / And the difference in decoding time. Assuming that the number of blocks of the base layer picture and the picture of the upper layer picture are all equal to N, and the difference between the blocks coding / decoding time of each layer is t, the time delay caused by encoding / decoding of the picture of the upper layer is t x N.

This time delay problem, particularly the time delay in the upper layer, is much more effective in the overall coding / decoding time than in the base layer, so that it is desirable to reduce it, or at least not to increase it.

FIG. 15 shows an example of a method of encoding / decoding a lower layer and a corresponding upper layer block in parallel, and FIG. 16 shows an example of an increase in encoding / decoding time due to dependency between upper layer blocks FIG.

FIG. 15 shows a case where encoding / decoding is performed by dividing E13 into four blocks. In this case, since the hierarchical image blocks E13A, E13B, E13C, and E13D of the respective layers are the same size as the image block of the base layer, there is not much difference from the base layer block in encoding / decoding.

However, there is a spatial dependency between the four blocks (E13A, E13B, E13C, E13D). As a result, they can only be sequentially encoded / decoded with each other, so they are encoded in the order as shown in Fig.

HEVC introduces the concept of Merge Estimation Region (MER). That is, in the MER area, spatial dependence is reduced, and motion prediction can be performed in parallel on blocks included in the area.

Consider the case of encoding / decoding the E13 block of the upper layer in FIG. If the PME is applied to the E13 block of the upper layer, since the base layer and the upper layer use the same PPS, the MER area setting for the PME of the base layer is directly applied to the upper layer. Therefore, in the upper layer, PME is applied only in each block of E13A, E13B, E13C, and E13D, and encoding / decoding dependency remains between E13A, E13B, E13C, and E13D blocks. That is, motion prediction is performed in parallel in the MER domain, but there is a dependency between the MER domains as in the case of a general block.

FIG. 17 is a diagram illustrating an example of a case where the MER size of the upper layer and the MER size of the base layer are the same for the corresponding block between the layers, FIG. 18 is a diagram illustrating a case where the MER size difference between the upper layer and the base layer FIG. 2 is a diagram showing an example of an increase in encoding / decoding time according to FIG.

As shown in FIG. 17, when encoding / decoding the lower layer MER0, the upper layer must encode / decode MER0-0, MER0-1, MER0-2, and MER0-3 in order. That is, the coding / decoding time increases due to the dependency between MERs in the upper layer. This is a problem that occurs because the MER size of the lower layer and the MER size of the upper layer are the same.

In this case, as in the case of FIG. 16, the dependency between MERs occurs as in the case of inter-block dependency, so that the coding / decoding time increases (FIG. 18).

In order to solve the above problems, according to the present invention, spatial dependency between blocks is eliminated. If the spatial dependency between the blocks is removed, each block can be encoded / decoded in parallel, so that the encoding / decoding time can be greatly reduced.

For example, if encoding is performed in parallel for each of the four blocks E13A, E13B, E13C, and E13D to encode E13 in FIG. 15, the encoding / decoding structure of FIG. 16 is changed to the structure shown in FIG. 19 .

19 is a diagram illustrating an example of coding / decoding time reduction by parallel coding / decoding of an upper layer block. As shown in FIG. 19, when B0 of the lower layer is encoded / decoded, E0A and E0B E0C E0D of the upper layer can be encoded / decoded in parallel. That is, if E0 including E0A and E0B E0C E0D of the upper layer is set as one MER, parallel merging motion prediction can be performed because inter-block availability is not applied between blocks in MER.

According to the present invention, in inter-picture coding, a method and apparatus for synchronizing an encoding / decoding time by setting an upper layer MER size based on a base layer MER size can be provided.

For this, it is possible to reduce the difference between the encoding / decoding time of the base layer block and the encoding / decoding time of the upper layer block by resetting the MER size in the upper layer according to the MER size in the base layer.

20 is a conceptual diagram of a time synchronization method according to an embodiment of the present invention. The MER shown in FIG. 20 is larger than the MER of the uppermost hierarchical layer shown in FIG.

FIG. 21 is a diagram illustrating an example of reduction in coding / decoding time due to MER size reset of an upper layer image. When the MER is reset according to FIG. 20, it is possible to reduce the difference between the encoding / decoding time of the base layer block and the encoding / decoding time of the upper layer block as shown in FIG. This method may be similar to performing the parallel encoding / decoding of the upper layer block shown in FIG.

22 is a control block diagram illustrating a structure of a decoder according to an embodiment of the present invention.

22 shows a case where MER information of an upper layer is set based on MER information of a lower layer. As shown in FIG. 22, when a bitstream of an image is input to a decoder, the bitstream separator 221 separates a bitstream of an upper layer and a bitstream of a lower layer into decoders 222 and 223 .

The bitstream separator 221 performs a role of delivering a bitstream including MER information to the MER parser 224. The MER information obtained from the MER parsing unit 224 is transmitted to the decoding units 222 and 223 of the respective layers.

The MER information transmitted to the upper layer is newly transmitted through the MER resuming unit 225 and then transmitted to the upper layer decoding unit 223. [

The decoding unit 222 of the base layer receives the MER information and the bitstream information corresponding to the base layer and reconstructs the image.

The decoding unit 223 of the upper layer receives the restored image (or block) of the base layer, the bitstream information corresponding to the upper layer, and the newly set MER information, and outputs the restored upper layer image.

The MER parsing unit 224 may be an independent component or may be a component merged or included in either the decoding unit 222 of the base layer or the decoding unit 223 of the upper layer.

The MER resetting unit 225 may be an independent component, as described above, or may be a component that is merged or included in the decryption unit 223 of the higher layer.

23 is a control block diagram illustrating a structure of a decoder according to another embodiment of the present invention.

FIG. 23 shows a decoder for cases where each MER information is separately coded. 23, when a bitstream of an image is input to a decoder, the bitstream separator 231 transfers a bitstream corresponding to an upper layer image to an upper layer decoder 233, Layer decoding unit 232. The layer-

The bitstream separator 231 separates the bitstream including the MER information of the upper layer into an upper layer MER parser 235 and the bitstream including the MER information of the base layer to the base layer MER parser 234 .

In the MER parser 235 of the upper layer, the MER information corresponding to the upper layer is transmitted to the upper layer decoder 233, and the MER parser of the base layer transmits the corresponding MER information to the base layer decoder 232 .

The base layer decoding unit 232 decodes the base layer bitstream and the base layer MER information, and restores the base layer image.

The upper layer decoding unit 233 receives the restored image (or block) of the base layer, the upper layer bitstream, and the upper layer MER information, and restores the image of the upper layer.

The base layer MER parsing unit 234 may be an independent component or may be a component merged or included in the base layer decoding unit 232 and the MER parsing unit 235 of the upper layer may be an independent component And may be a component that is merged or included in the upper layer decoding unit 233.

24 is a block diagram illustrating a structure of an encoder according to an embodiment of the present invention.

24 shows an encoder in a case where MER information of an upper layer is set based on MER information of a lower layer.

In FIG. 24, the base layer encoding unit 242 receives the base layer image and base layer MER information set in the base layer MER setting unit 241, and proceeds to the encoding in the base layer encoding unit 242.

The upper layer MER setting unit 243 receives the MER information set by the base layer MER setting unit 241, and resets the MER information of the upper layer.

The upper layer coding unit 244 receives the upper layer image, the base layer image (or block), and the upper layer MER information, and encodes the upper layer image.

When the images of the respective layers are encoded, the bitstream integrating unit 245 integrates and transmits the bitstreams into one bitstream.

25 is a block diagram illustrating a structure of an encoder according to another embodiment of the present invention. 25 shows an encoder in which MER information of each layer is separately encoded.

In FIG. 25, when the base layer MER information and the base layer image set in the base layer MER setting unit 251 are input to the base layer encoding unit 252, the base layer image encoding is performed.

When the upper layer MER information, the base layer image (or block), and the upper layer image set in the upper layer MER setting unit 253 are input to the upper layer encoding unit 254, the upper layer image is encoded.

The bit streams of the respective layers, which have been encoded by the encoding units of the respective layers, are integrated into one bit stream by the bit stream integrating unit 255.

Hereinafter, a specific method of the present invention will be described in which the MER can be generated according to the MER size relationship between the upper layer image and the base layer image.

26 is a diagram illustrating an example in which an image size of an upper layer is larger than an image size of a base layer according to the present invention.

As shown in FIG. 26, when the image size of the upper layer is larger than the image size of the base layer, the value of log2_parallel_merge_level_minus2 of the upper layer is reset by adding +1 to log2_parallel_merge_level_minus2 of the base layer.

The size of the MER is defined as the value of log2_parallel_merge_level_minus2 of the PPS syntax in HEVC. Therefore, the value of log2_parallel_merge_level_minus2 in the upper layer can be reset based on the value of log2_parallel_merge_level_minus2 in the base layer.

27 is a diagram illustrating an example in which an image size of an upper layer is smaller than an image size of a base layer according to the present invention

As shown in FIG. 27, when the image size of the upper layer is smaller than the image size of the base layer, log2_parallel_merge_level_minus2 of the upper layer is reset by adding -1 to log2_parallel_merge_level_minus2 of the base layer.

The size of the MER is defined as the value of log2_parallel_merge_level_minus2 of the PPS syntax in HEVC. Therefore, the value of log2_parallel_merge_level_minus2 in the upper layer can be reset based on the value of log2_parallel_merge_level_minus2 in the base layer.

In general, if the above two cases are included, the log2_parallel_merge_level_minus2 value of the upper layer image can be reset through comparing the image size of the base layer with the image size of the upper layer and the ratio between the image sizes.

28 is a diagram illustrating an example of a control flowchart of an algorithm for determining an MER size of an upper layer according to an image proportional value of an upper layer and a base layer according to the present invention.

First, the picture ratios of the base layer and the upper layer are grasped (S281).

For example, suppose the width of the base layer image is 640 and the value of log2_parallel_merge_level_minus2 is 3, that is, the size of the MER is 32x32 and the width of the upper layer image is 1280.

At this time, the ratio of the picture width (bl_pic_width) of the base layer to the picture width (el_pic_width) of the upper layer is 2 (1280/640).

When the picture ratio of the base layer and the upper layer is determined, it is determined whether the ratio is equal to or larger than 1, and the ratio is reset according to the determination result. The MER of the upper layer is also reset according to the re-established ratio.

If the picture width of the upper layer is twice as large as the picture width of the base layer and the ratio value is larger than 1 (S282) as in the above-described assumption, the new ratio value becomes 1, which is 2 divided by 2, and log2_parallel_merge_level_minus2 Is added to the value of log2_parallel_merge_level_minus2 in the base layer by adding one to three. Therefore, the size of the MER of the upper layer image is 64x64.

 As another example, assume that the width of the base layer image and the width of the upper layer image are equal to 1280. The value of log2_parallel_merge_level_minus2 in the lower layer is 4, that is, the size of the MER is 64x64, and the ratio is 1. If the ratio is divided by 2, it is 0.5, and since the decimal point is discarded, the new ratio value becomes 0. Therefore, 0 is added to log2_parallel_merge_level_minus2 of the base layer image, so log2_parallel_merge_level_minus2 of the upper layer image becomes equal to the value of the lower layer image.

That is, if the ratio of the picture width (bl_pic_width) of the base layer to the picture width (el_pic_width) of the upper layer is equal to or larger than 1, the new ratio is set to ratio 1 and the MER (el_log2_parallel_merge_level_minus2) Is set to a value obtained by adding a new ratio to the MER of the base layer (bl_log2_parallel_merge_level_minus2) (S283).

If the ratio is less than 1 (S284), the new ratio is set to (1 / ratio) " 1, and the MER of the upper layer to be reset (el_log2_parallel_merge_level_minus2) Is set to a value obtained by subtracting the new ratio from the MER of the base layer (bl_log2_parallel_merge_level_minus2) (S285).

For example, suppose that the width of the base layer image is 1280 and the value of log2_parallel_merge_level_minus2 is 3, that is, the size of the MER is 32x32 and the width of the upper layer image is 320. In this case, the ratio becomes 320/1280 and becomes 1/4.

Since the ratio is less than 1, it is 4 if it is reversed and 2 if it is halved. Therefore, if the ratio value 2 is subtracted from the bl_log2_parallel_merge_level_minus2 value 3 of the base layer, the value becomes 1, and the size of the MER (el_log2_parallel_merge_level_minus2) of the upper layer becomes 8x8.

If the MER (el_log2_parallel_merge_level_minus2) of the upper layer is smaller than 0 (S286), the MER (el_log2_parallel_merge_level_minus2) of the upper layer is set to 0 (S287).

According to another embodiment of the present invention, the syntax information shared between the base layer and the upper layer can be divided into signals for each layer.

In the existing SHVC structure, there is no PPS for each layer, and one PPS is shared between the base layer and the upper layer. Due to this, the same MER is used for each layer by the MER information included in the PPS.

In order to set the MER differently for each layer, it is possible to signal MER setting information for each layer. For example, the layer-by-layer MER setting information may be transmitted by including a video parameter set (VPS), a sequence parameter set (SPS), a picture parameter set (PPS) Through this method, the base layer and the MER size can be changed by using a new MER size in the upper layer.

All of the above methods can be applied differently depending on block size or CU depth. The variable (i.e., size or depth information) for determining the coverage can be set to use a predetermined value by the encoder or decoder, use a predetermined value according to the profile or level, If signaling to the bitstream, the decoder may use this value from the bitstream.

When applying CU to different depths, as shown in Table 1 below, a method that applies only to a given depth or more (Method A), a method that applies only to a given depth or less (Method B) There is a way (method C).

Table 1 below shows an example of the range determination method applying the methods of the present invention when the given CU depth is 2. At this time, O indicates that it is applied to the corresponding depth, and X indicates that it does not apply to the corresponding depth.

<Table 1>

When the methods of the present invention are not applied to all the depths, they may be indicated by using an optional flag, or a value one greater than the maximum value of the CU depth may be expressed by signaling with a CU depth value indicating the application range have.

In addition, the above-described method can be applied to color difference blocks differently depending on the size of a luminance block, and can be applied to a luminance signal image and a chrominance image differently.

FIG. 29 is a diagram illustrating an embodiment for combining methods according to the present invention.

Among the modified methods of Fig. 29, when the method of &quot; H1 &quot; is described as the case where the size of the luminance block is 8 (8x8, 8x4, 2x8, etc.) and the size of the color difference block is 4 (4x4, 4x2, 2x4) The method of the specification can be applied to the luminance signal and color difference signal, and the horizontal signal and the vertical signal.

Among the above modified methods, the method "wave 2" is a case where the size of a luminance block is 16 (16 × 16, 8 × 16, 4 × 16, etc.) and the size of a color difference block is 4 (4 × 4, 4 × 2, 2 × 4) The method of the specification may be applied to the luminance signal and the color difference signal and the horizontal signal and not to the vertical signal.

In another modified method, the method of the specification is applied only to the luminance signal and may not be applied to the color difference signal. Conversely, the method of the specification is applied only to the color difference signal, and may not be applied to the luminance signal.

The method according to the present invention may be implemented as a program for execution on a computer and stored in a computer-readable recording medium. Examples of the computer-readable recording medium include a ROM, a RAM, a CD- , A floppy disk, an optical data storage device, and the like, and may also be implemented in the form of a carrier wave (for example, transmission over the Internet).

The computer readable recording medium may be distributed over a networked computer system so that computer readable code can be stored and executed in a distributed manner. And, functional programs, codes and code segments for implementing the above method can be easily inferred by programmers of the technical field to which the present invention belongs.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, It should be understood that various modifications may be made by those skilled in the art without departing from the spirit and scope of the present invention.

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

100: image encoding device 111: motion prediction unit
112: motion compensation unit 120: intra prediction unit
115: Switch 125:
130: conversion unit 140: quantization unit
150: an entropy encoding unit 160: an inverse quantization unit
170: inverting section 180: filter section

Claims (16)

A method of decoding an image supporting a plurality of layers,
Decoding a reference block of a base layer that can be referred to by a target block of an upper layer to be decoded;
Setting a parallel merging motion prediction range of the upper layer based on a size of a parallel merging motion prediction range of the base layer;
Deriving a parallel merging motion prediction list for a target block of the upper layer based on the reference blocks existing in the parallel merging motion prediction range of the base layer;
And performing parallel motion compensation on the target block based on the parallel merging motion prediction list,
Wherein the image supporting the plurality of layers includes an image classified based on at least one of spatial, temporal, and image quality. The method according to claim 1,
Wherein the parallel merging motion prediction range of the target block is set according to a ratio of a picture width of the base layer and a picture width of the upper measurement. 3. The method of claim 2,
If the ratio of the picture width of the base layer to the picture width of the upper metric (hereinafter referred to as a first ratio) is 1 or more,
Wherein the parallel merging motion prediction range of the target block is set to a predetermined level value representing a parallel merging motion prediction range of the reference block plus a second ratio corresponding to a quotient obtained by dividing the first ratio by 2 The method comprising: 3. The method of claim 2,
If the ratio of the picture width of the base layer to the picture width of the upper metric (hereinafter, the first ratio) is less than 1,
The parallel merging motion prediction range of the target block is set to a value obtained by subtracting a second ratio corresponding to a quotient obtained by dividing the inverse number of the first ratio by 2 from a predetermined level value indicating a parallel merging motion prediction range of the reference block And decodes the decoded image. The method according to claim 3 or 4,
Wherein the level value is derived through decoding of a syntax element log2_parallel_merge_level_minus2 for the base layer. The method according to claim 1,
Further comprising the step of receiving a predetermined syntax element indicating a parallel merging motion prediction range of the target block. The method according to claim 1,
Wherein the target block is a coding block divided into at least two prediction blocks,
And a parallel merging motion list is generated between prediction blocks included in the parallel merging motion prediction range. The method according to claim 1,
Wherein the parallel merging motion prediction range of the target block is set to a predetermined size according to whether the target block is a luminance block or a color difference block. An apparatus for decoding an image supporting a plurality of layers,
A base layer decoding unit for decoding a reference block of a base layer that can be referred to by a target block of an upper layer to be decoded;
A parallel merging motion prediction range including the target block is set based on a size of a parallel merging motion prediction range including a reference block of the base layer, And an upper layer decoding unit for deriving a parallel merging motion prediction list for the target block and performing parallel motion compensation on the target block based on the parallel merging motion prediction list,
Wherein the image supporting the plurality of layers includes an image classified based on at least one of spatial, temporal, and image quality. 10. The method of claim 9,
Wherein the upper layer decoding unit sets a parallel merging motion prediction range of the target block according to a ratio of a picture width of the base layer and a picture width of the upper measurement. 11. The method of claim 10,
If the ratio of the picture width of the base layer to the picture width of the upper metric (hereinafter referred to as a first ratio) is 1 or more,
Wherein the upper layer decoding unit compares a parallel merging motion prediction range of the target block with a predetermined level value indicating a parallel merging motion prediction range of the reference block plus a second ratio corresponding to a quotient obtained by dividing the first ratio by 2 And decodes the decoded image. 11. The method of claim 10,
If the ratio of the picture width of the base layer to the picture width of the upper metric (hereinafter, the first ratio) is less than 1,
Wherein the upper layer decoding unit compares the parallel merging motion prediction range of the target block with a predetermined level value indicating a parallel merging motion prediction range of the reference block minus a second ratio corresponding to a quotient obtained by dividing the inverse number of the first ratio by 2 Value of the video signal. 13. The method according to claim 11 or 12,
Wherein the upper layer decoding unit derives the level value by decoding a syntax element log2_parallel_merge_level_minus2 for the base layer. 10. The method of claim 9,
Wherein the upper layer decoding unit receives and parses a predetermined syntax element indicating a parallel merging motion prediction range of the target block. 10. The method of claim 9,
Wherein the target block is a coding block divided into at least two prediction blocks,
Wherein the upper layer decoding unit generates a parallel merging motion list between prediction blocks included in the parallel merging motion prediction range. 10. The method of claim 9,
Wherein the upper layer decoding unit sets a parallel merging motion prediction range of the target block to a predetermined size according to whether the target block is a luminance block or a color difference block.

Images