Technology for improving coding efficiency by performing a block split suitable for picture coding and decoding is provided. A picture decoding device includes a spatial candidate derivation unit configured to derive a spatial candidate from inter prediction information of a block neighboring a decoding target block and register the derived spatial candidate as a candidate in a first candidate list, a history-based candidate derivation unit configured to generate a second candidate list by adding a history-based candidate included in a history-based candidate list as a candidate to the first candidate list, a candidate selection unit configured to select a selection candidate from candidates included in the second candidate list; and an inter prediction unit configured to perform inter prediction using the selection candidate. The history-based candidate derivation unit switches between whether or not a history-based candidate overlapping a candidate included in the first candidate list is added in accordance with a prediction mode.

A motion vector coding unit executes processing including a neighboring block specification step of specifying a neighboring block which is located in the neighborhood of a current block; a judgment step of judging whether or not the neighboring block has been coded using a motion vector of another block; a prediction step of deriving a predictive motion vector of the current block using a motion vector calculated from the motion vector of the other block as a motion vector of the neighboring block; and a coding step of coding the motion vector of the current block using the predictive motion vector.

A motion vector coding unit executes processing including a neighboring block specification step of specifying a neighboring block which is located in the neighborhood of a current block; a judgment step of judging whether or not the neighboring block has been coded using a motion vector of another block; a prediction step of deriving a predictive motion vector of the current block using a motion vector calculated from the motion vector of the other block as a motion vector of the neighboring block; and a coding step of coding the motion vector of the current block using the predictive motion vector.

A better compromise between encoding complexity and achievable rate distortion ratio, and/or to achieve a better rate distortion ratio is achieved by using multitree sub-divisioning not only in order to subdivide a continuous area, namely the sample array, into leaf regions, but using the intermediate regions also to share coding parameters among the corresponding collocated leaf blocks. By this measure, coding procedures performed in tiles—leaf regions—locally, may be associated with coding parameters individually without having to, however, explicitly transmit the whole coding parameters for each leaf region separately. Rather, similarities may effectively exploited by using the multitree subdivision.

A better compromise between encoding complexity and achievable rate distortion ratio, and/or to achieve a better rate distortion ratio is achieved by using multitree sub-divisioning not only in order to subdivide a continuous area, namely the sample array, into leaf regions, but using the intermediate regions also to share coding parameters among the corresponding collocated leaf blocks. By this measure, coding procedures performed in tiles—leaf regions—locally, may be associated with coding parameters individually without having to, however, explicitly transmit the whole coding parameters for each leaf region separately. Rather, similarities may effectively exploited by using the multitree subdivision.

According to the present invention, an image encoding apparatus comprises: a motion prediction unit which derives motion information on a current block in the form of the motion information including L0 motion information and L1 motion information; a motion compensation unit which performs a motion compensation for the current block on the basis of at least one of the L0 motion information and L1 motion information so as to generate a prediction block corresponding to the current block; and a restoration block generating unit which generates a restoration block corresponding to the current block based on the prediction block. According to the present invention, image encoding efficiency can be improved.

A method of encoding an image in a merge mode, the method including determining motion information of a current prediction unit, and generating a prediction block using the motion information; generating a residual block using an original block and the prediction block, transforming the residual block to generating a transformed block, quantizing the transformed block using a quantization parameter to generate a quantized block, and scanning the quantized block to entropy-code the quantized block; and encoding the motion information using effective spatial and temporal merge candidates of the current prediction unit. Further, a motion vector of the temporal merge candidate is a motion vector of a temporal merge candidate within a temporal merge candidate picture, and the quantization parameter is encoded using an average of two effective quantization parameters among a left quantization parameter, an upper quantization parameter and a previous quantization parameter of a current coding unit, also when the quantized block is larger than a predetermined size, the quantized block is divided into a plurality of subblocks to be scanned, and a scan pattern for scanning the plurality of subblocks is the same as a scan pattern for scanning quantized coefficients within each subblock. In addition, information indicating a position of a last non-zero quantized coefficient in a transform unit is transmitted to a video decoder.

A method of encoding an image in a merge mode, the method including determining motion information of a current prediction unit, and generating a prediction block using the motion information; generating a residual block using an original block and the prediction block, transforming the residual block to generating a transformed block, quantizing the transformed block using a quantization parameter to generate a quantized block, and scanning the quantized block to entropy-code the quantized block; and encoding the motion information using effective spatial and temporal merge candidates of the current prediction unit. Further, a motion vector of the temporal merge candidate is a motion vector of a temporal merge candidate within a temporal merge candidate picture, and the quantization parameter is encoded using an average of two effective quantization parameters among a left quantization parameter, an upper quantization parameter and a previous quantization parameter of a current coding unit, also when the quantized block is larger than a predetermined size, the quantized block is divided into a plurality of subblocks to be scanned, and a scan pattern for scanning the plurality of subblocks is the same as a scan pattern for scanning quantized coefficients within each subblock. In addition, information indicating a position of a last non-zero quantized coefficient in a transform unit is transmitted to a video decoder.

A video decoding method that includes: receiving information for deriving motion information of a current block; deriving the motion information of the current block based on the received information for deriving the motion information; and performing prediction to generate predicted pixels of the current block based on the motion information of the current block, wherein the motion information of the current block is determined by using motion information of a reference block, wherein the reference block is determined based on a specific disparity vector, wherein the specific disparity vector is determined for an area in a picture to which the current block belongs, wherein the area which the specific disparity vector is determined is split based on a quad tree structure, and wherein the current block is a block of a texture picture and the reference block is a block in a reference view is disclosed.

A video decoding method that includes: receiving information for deriving motion information of a current block; deriving the motion information of the current block based on the received information for deriving the motion information; and performing prediction to generate predicted pixels of the current block based on the motion information of the current block, wherein the motion information of the current block is determined by using motion information of a reference block, wherein the reference block is determined based on a specific disparity vector, wherein the specific disparity vector is determined for an area in a picture to which the current block belongs, wherein the area which the specific disparity vector is determined is split based on a quad tree structure, and wherein the current block is a block of a texture picture and the reference block is a block in a reference view is disclosed.