KR101979781B1 - Apparatus and Method of Adaptive Quantization Parameter Encoding and Decoder based on Quad Tree Structure - Google Patents

Abstract

A video encoding / decoding method and apparatus are disclosed. An apparatus for decoding an image according to the present invention includes an inverse quantization difference value recording block unit determination unit for determining a unit of a block in which an inverse quantization difference value is to be recorded, An inverse quantization parameter prediction block determining unit for determining a block to be used for prediction of the inverse quantization parameter using the position information of the block, an inverse quantization parameter estimating unit for estimating the inverse quantization parameter based on the inverse quantization difference value, An inverse quantization parameter value deriving unit for obtaining an inverse quantization parameter value, and an inverse quantization unit for performing inverse quantization using the inverse quantization parameter value.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus for encoding and decoding an adaptive quantization parameter based on a quad tree structure,

The present invention relates to an image encoding / decoding apparatus and method, and more particularly, to an image encoding / decoding apparatus and method for displaying a block having a quantization / dequantization difference value based on a quadtree structure with respect to CUs in an LCU, And a method and apparatus for adaptively predicting / decoding a quantization / dequantization parameter value using context information of blocks located in a block.

The HEVC encodes / decodes the input image in units of CU (Coding Unit). The maximum size CU in a frame is called an LCU (Largest Coding Unit). The LCU can be divided into a plurality of CUs based on the quadtree division information, and then encoded / decoded. The quantization parameter values of the HEVC are assigned one value in units of LCU, and the quantization parameter value of the LCU to be encoded is predicted in the LCU located before based on the raster scan order.

H.264 / AVC is encoded / decoded in units of macroblocks and has quantization / dequantization values in units of macroblocks. The quantization parameter values allocated on a macroblock basis are predicted from the quantization parameter values of macroblocks located on the left in the frame. Encoding is performed by writing the corresponding value in the macroblock to be encoded with respect to the difference value generated after the prediction process of the value of the quantization parameter. The decoder decodes the quantization parameter value by adding the quantization parameter difference value decoded in the entropy decoding step and the quantization parameter value of the macro block located on the left.

However, when a relatively large LCU is allocated as compared with the size of the input image, it is not possible to effectively control the bit rate using quantization parameter values recorded in units of LCUs. In addition, when a quantization parameter value is allocated in units of CU, a problem of lowering subjective image quality due to a difference of quantization parameter values with neighboring CUs may occur. Accordingly, it is necessary to allocate quantization parameter values to various block sizes from CU to LCU according to the input image, and to optimize the prediction direction of the quantization parameter using the context information of the blocks located around the block to be encoded .

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method and apparatus for encoding / decoding quantization / dequantization parameter values based on various quad tree structures based on division information of CUs. The quantization / dequantization parameter encoding / decoding method and apparatus also provide a method and apparatus for predicting quantization / dequantization parameter values in an effective direction using context information of neighboring blocks.

The present invention has been made in view of the above problems, and it is an object of the present invention to provide an apparatus and method for controlling the same.

According to an aspect of the present invention, there is provided an apparatus and method for encoding an image, the method comprising the steps of: A quantization unit for performing quantization using the quantization values allocated on a block-by-block basis, and a quantization unit for determining the quantization value using the context information of neighboring blocks in order to predict a quantization value used in a block to be encoded A quantization parameter difference value generation unit for generating a quantization difference value of a block to be encoded using a quantization parameter of a prediction block obtained based on context information, a quantization parameter difference value generation unit for quantizing a difference value The division information for the block unit and the quantization parameter Minutes and a quantization parameter recording unit operable to record the value.

According to an aspect of the present invention, there is provided an image decoding apparatus including an inverse quantization parameter difference value block division flag derivation unit for decoding information on a block having an inverse quantization parameter difference value in units of LCUs, An inverse quantization difference value block determination unit for determining a block unit in which an inverse quantization difference value is recorded in the LCU by using a parameter difference value block division flag, and an inverse quantization parameter difference value determination unit for determining an inverse quantization parameter difference value An inverse quantization parameter difference value derivation unit for decoding the inverse quantization parameter difference value of the block to be decoded, an inverse quantization parameter value derivation unit for decoding the inverse quantization parameter difference value of the block to be decoded using the context information of the neighboring block, To decode the inverse quantization parameter value Inverse quantization parameter value derivation unit, using the decoded inverse quantization parameter value and comprising an inverse quantizer that performs inverse quantization.

The quad tree structure based adaptive quantization / dequantization parameter encoding and decoding method and apparatus according to the present invention enable allocation of quantization parameter difference values at various levels when blocks are divided in a quadtree structure . This different level of quantization parameter difference value assignment allows more finer bit amount adjustment than assigning a single quantization parameter value in LCU units. When predicting / decoding the quantization / dequantization parameter value of a block unit, not only a zigzag scanning method based on a quadtree structure but also a quantization process with surrounding blocks is performed by determining a prediction direction adaptively using context information of neighboring blocks, It is possible to solve the subjective image quality degradation problem that may occur due to a large difference in the values.

FIG. 1A is a first embodiment of the present invention, which relates to a method and apparatus for adaptively assigning quantization parameter values to a block having a quad-tree structure in an image encoding apparatus and encoding the quantized parameter values.
FIG. 1B illustrates a method and an apparatus for decoding an adaptive inverse quantization parameter based on a quad tree structure in a video decoding apparatus according to a first embodiment of the present invention.
2 is a block diagram of a video decoding apparatus according to a first embodiment of the present invention.
FIG. 3 illustrates a context for quantization differential value control based on a quadtree structure recorded in a sequence parameter set according to the first embodiment of the present invention.
FIG. 4 is a diagram illustrating variables set as initial values in the slice data according to the first embodiment of the present invention.
FIG. 5 relates to a quantization / inverse quantization parameter difference value recorded in a unit of CU according to the first embodiment of the present invention and a context of a condition in which the difference value exists.
FIG. 6 illustrates operations of a quantization difference value recording block unit determination unit and an inverse quantization difference value recording block unit determination unit according to an embodiment of the present invention.
7 is a block diagram of a quantization parameter value prediction block determination unit and an inverse quantization parameter value prediction block determination unit according to the first embodiment of the present invention.
8 is a block diagram of a quantization parameter value prediction block determination unit and an inverse quantization parameter value prediction block determination unit according to a second embodiment of the present invention.
9 is a block diagram of a quantization parameter value prediction block determination unit and an inverse quantization parameter value prediction block determination unit according to a third embodiment of the present invention.
FIG. 10 shows a quantization parameter value prediction block determination unit 102 and an inverse quantization parameter value prediction block determination unit 123 according to a fourth embodiment of the present invention.
11 is a block diagram of a quantization parameter value prediction block determination unit and an inverse quantization parameter value prediction block determination unit according to a fifth embodiment of the present invention.

Hereinafter, an adaptive quantization / dequantization parameter encoding and decoding apparatus based on a quadtree structure according to an embodiment of the present invention will be described with reference to the accompanying drawings.

FIG. 1A is a first embodiment of the present invention, which relates to a method and apparatus for adaptively assigning quantization parameter values to a block having a quad-tree structure in an image encoding apparatus and encoding the quantized parameter values.

1A, a method and apparatus for adaptive quantization parameter coding based on a quad tree structure includes a quantization difference value recording block unit determination unit 100, a quantization unit 101, a quantization parameter value prediction block determination unit 102, A difference value generation unit 103, and a quantization parameter recording unit 104. [

The quantization difference value recording block unit determination unit 100 determines a block unit so that a quantization difference value can be recorded for each CU unit or a plurality of sets of CUs based on the CU division information of the corresponding LCU in units of LCUs in an image do. The information of the block for recording the quantization difference value may be constituted by a quadtree structure.

The quantization unit 101 quantizes the input block using the quantization parameter assigned to the block.

The quantization parameter value prediction block determination unit 102 uses the context information of the CU located in the periphery of the corresponding CU to effectively quantize the quantization values allocated to the respective CUs or arbitrary CUs, . As the context information, a size of a block, a position of a block, a prediction mode of a block, and the like can be used.

The quantization parameter difference value generation unit 103 generates a quantization parameter difference value by subtracting the quantization value of the current block from the quantization parameter value of the quantization value prediction block determined by the quantization parameter value prediction block determination unit 102. [

The quantization parameter recording unit 104 is used for indicating a sequence parameter set for adaptive quantization parameter coding based on a quad tree structure, flag information on application / non-application in units of slices, and division information of a block including a quantization difference value in the LCU Flag information, and the quantization parameter difference value.

FIG. 1B illustrates a method and an apparatus for decoding an adaptive inverse quantization parameter based on a quad tree structure in a video decoding apparatus according to a first embodiment of the present invention.

Referring to FIG. 1B, a method and apparatus for decoding an adaptive inverse quantization parameter based on a quad tree structure includes an inverse quantization parameter difference value block division flag derivation unit 120, an inverse quantization difference value recording block unit determination unit 121, A difference value derivation unit 122, an inverse quantization parameter value prediction block determination unit 123, an inverse quantization parameter value derivation unit 124, and an inverse quantization unit 125. [

The inverse quantization parameter difference value block division flag derivation unit 120 decodes a block division flag for a block having an inverse quantization parameter difference value in LCU units in a sequence parameter set and slice data.

The inverse quantization difference value recording block unit determination unit 121 determines the blocks in which the inverse quantization parameter difference value is recorded using the decoded inverse quantization parameter difference value block division flag and the CU division flag. The information of the block for recording the quantization difference value may be constituted by a quadtree structure.

The inverse quantization parameter difference value derivation unit 122 derives an inverse quantization parameter difference value for each block determined by the inverse quantization difference value recording block unit determination unit 121. [

The inverse quantization parameter value prediction block determination unit 123 determines a block to be referred to adaptively using the context information of a neighboring block when inverse quantization is performed. As the context information, a size of a block, a position of a block, a prediction mode of a block, and the like can be used.

The inverse quantization parameter value derivation unit 124 obtains the inverse quantization parameter value of the prediction block calculated through the inverse quantization parameter value prediction block determination unit 123 and the inverse quantization parameter value derivation unit 122 using the inverse quantization parameter value derivation unit 122. [ The inverse quantization parameter value to be used for the inverse quantization unit 125 is derived by adding the parameter difference value.

The inverse quantization unit 125 performs inverse quantization on the input block using the parameters calculated in the inverse quantization parameter value derivation unit 124 and the like.

2 is a block diagram of a video decoding apparatus according to a first embodiment of the present invention.

2, the image decoding apparatus includes an entropy decoding unit 200, a quadtree-based dequantization parameter deriving unit 210, a reordering unit 220, an inverse quantization unit 230, an inverse discrete cosine transform encoding unit 240, An intra / inter prediction unit 250, and a filtering unit 260.

The entropy decoding unit 200 includes an inverse quantization parameter difference value block division flag derivation unit 120 for deriving a block division flag written for adaptive inverse quantization based on a quad tree structure, An inverse quantization difference value recording block unit determination unit 121 for determining a recorded block, and an inverse quantization parameter difference value derivation unit 122 for decoding the inverse quantization parameter difference value recorded in the corresponding block.

The quadtree-based dequantization parameter derivation unit 210 includes an inverse quantization parameter value prediction block determination unit 123 that determines a prediction block to be referred to when decoding the inverse quantization parameter, a dequantization parameter determination unit 123 that determines an inverse quantization parameter And an inverse quantization parameter value derivation unit 124 for computing an inverse quantization parameter by adding the difference value, and the inverse quantization parameter value derivation unit 124 restores the inverse quantization parameter for the block of the quad tree structure.

FIG. 3 illustrates a context for quantization differential value control based on a quadtree structure recorded in a sequence parameter set according to the first embodiment of the present invention.

If the value of cu_qp_delta_enabled_flag (300) in the sequence parameter set is 1, it means that the quantization / dequantization parameter difference value can be controlled for various quad-tree blocks from the minimum size CU to the maximum size CU in all the slices in the sequence do.

FIG. 4A is a diagram illustrating variables set as initial values in the slice data according to the first embodiment of the present invention.

When a slice is divided into a quad tree structure and is encoded / decoded, the slice is first divided into LCU units of a maximum size quad tree, and the LCUs are encoded / decoded in order of the sequential scanning scheme. In the case of encoding / decoding each LCU, the corresponding LCU can be divided into a plurality of CU regions based on a quadtree structure, and the division can be performed until the minimum CU size.

In FIG. 4A, isCuQpDeltaCoded 400 is a variable for controlling the quantization / dequantization parameter difference value that can be recorded in each CU when an arbitrary CU is again divided into N CUs. This value is always initialized to zero before performing the encoding / decoding for each LCU in the slice.

In FIG. 4A, the coding_tree (401) function is a function for performing encoding / decoding on one LCU in a slice. The fourth argument of the function is a flag indicating whether a quantization / dequantization parameter difference value exists in the corresponding CU. Since at least one quantization / dequantization parameter difference value is recorded in an LCU unit, This value is always called 1 before encoding / decoding.

FIG. 4B relates to the context of the inverse quantization parameter difference value block division recorded in the coding tree block according to the first embodiment of the present invention.

A coding tree block represents a context for a CU. A CU of 2N × 2N size can be divided into four CUs of N × N size according to split_coding_unit_flag (420), and then can be encoded / decoded. Alternatively, it may be encoded / decoded into a 2N x 2N CU that is the current size rather than being divided into CUs with a smaller size.

The current CU receives a cu_qp_delta_exist_flag (421) as a flag indicating whether a quantization / dequantization parameter differential value exists in a higher level CU. When the current CU of 2N × 2N size is divided into N × N CUs again according to the value of split_coding_unit_flag (420), the split_qp_delta_flag 422 is further encoded / decoded. This additional division information is encoded / decoded only when the cu_qp_delta_enable_flag (300) value recorded in the sequence parameter set and the cu_qp_delta_exist_flag (421) input from the upper CU are 1. The value of the split_qp_delta_flag 422 is encoded / decoded only when the current CU of 2N × 2N size is divided into N × N, and the corresponding value is input as the value of cu_qp_delta_exist_flag (421) when encoding / decoding the N × N lower CUs .

When the value of the split_qp_detla_flag 422 is 0, the current CU of 2N × 2N size is divided into CU of N × N size, but the size of the block for recording the quantization / inverse quantization parameter difference value is 2N × 2N to N × N size Lt; RTI ID = 0.0 > block < / RTI > If the value of split_qp_detla_flag (422) is 0, the value of IsCuQpDeltaCoded (400) is additionally initialized to 0 so that the quantization / inverse quantization parameter difference value is recorded only in the first NxN CU when divided into NxN CUs .

FIG. 5 relates to a quantization / inverse quantization parameter difference value recorded in a unit of CU according to the first embodiment of the present invention and a context of a condition in which the difference value exists.

If the CU is not in the skip mode, the quantization / dequantization parameter difference value may be recorded in the corresponding CU. If the value of cu_qp_delta_exist_flag (500; 421) is 1, it means that the quantization / dequantization parameter difference value exists in the current CU. In this case, the cu_qp_delta_enabled_flag (300) value recorded in the sequence parameter set Can be recorded in units of CU. For example, when the value of cu_qp_delta_exist_flag (500; 421) is 1 and the value of cu_qp_delta_enabed_flag (300) is 0, cu_qp_delta (501) is not recorded.

As another example, when a 2N x 2N CU is divided into four N x N CUs in the quadtree structure, only one value of the quantization / dequantization parameter difference value may be recorded. In this case, the quantization / dequantization parameter difference value is recorded in the first CU among the four CUs, and the quantization / dequantization parameter difference value is not recorded in the remaining three CUs. At this time, the value of split_qp_delta_flag (422) for encoding / decoding in 2N × 2N CU is 0, so that the value of cu_qp_delta_exist_flag (500) input to N × N CU becomes zero. Therefore, cu_qp_delta (501) does not exist basically in the four divided NxN CUs, but the value of cu_qp_delta (501) can be recorded in the first NxN CU by using the IsCuQpDeltaCoded variable. For the remaining three CUs, the value of cu_qp_delta (501) is not recorded because the first CU decodes cu_qp_delta (501) and then changes the IsCuQpDeltaCoded value to 1.

Also in this case, the condition of the value of cu_qp_delta_enabled_flag (300) recorded in the sequence parameter set is simultaneously checked, and the value of cu_qp_delta (501) can be recorded only when the corresponding value is 1.

FIG. 6A illustrates operations of the quantization difference value recording block unit determination unit 100 and the inverse quantization difference value recording block unit determination unit 121 according to the first embodiment of the present invention.

A 2N × 2N LCU to be encoded / decoded can be divided into 4 N × N CUs, and each CU is further divided and processed. Even if the LCU of 2N x 2N size is divided into a plurality of CUs and coded / decoded, when the value of split_qp_delta_flag 422 is 0 as shown in Fig. 6A, the quantization / dequantization parameter difference value is recorded in the first CU of the LCU. The remaining CUs of the LCU use the quantization / dequantization parameter values recovered from the first CU.

FIG. 6B relates to operations of the quantization difference value recording block unit determination unit 100 and the inverse quantization difference value recording block unit determination unit 121 according to the second embodiment of the present invention.

The 2N × 2N LCU to be encoded / decoded is divided into four CUs in the first stage, and the second CU of the corresponding CUs is further divided. In this case, when the CU is coded / decoded in the first step, the split_qp_delta_flag (422; 630), which is a division flag for the quantization / dequantization parameter value, is further encoded / decoded. If the corresponding value is 1, it means that all four CUs have a quantization / dequantization parameter difference value. Therefore, the split flag split_qp_delta_flag (422; 631) for the quantization / dequantization parameter value is additionally encoded / Decrypted.

In this case, even though the CU is divided up to the third stage of the second N × N CU, since the split flag of split_qp_delta_flag (422; 631) for quantization / dequantization is 0, only one quantization / dequantization parameter value .

FIG. 6C illustrates operations of the quantization difference value recording block unit determination unit 100 and the inverse quantization difference value recording block unit determination unit 121 according to the third embodiment of the present invention.

FIG. 6C shows a case in which a 2N × 2N LCU to be encoded / decoded is divided into four CUs in the first stage, and the second CU of the corresponding CUs is further divided. The size of the block in which the quantization / dequantization parameter difference value is recorded can be determined through the value of split_qp_delta_flag (422; 661) even when the second CU is divided again into four CUs and the divided CU is divided again into four CUs have. 6C shows that the CU is divided into a maximum of 3 depth information, but a relatively quantized / dequantized parameter difference value has a maximum of 2 depth information.

FIG. 7A relates to a quantization parameter value prediction block determination unit 102 and an inverse quantization parameter value prediction block determination unit 123 according to the first embodiment of the present invention.

The encoder allocates the quantization parameter values to the CU blocks determined through the quantization difference value recording block unit determination unit 100 and uses the previously used quantization parameter values as they are for the remaining CU blocks. At this time, the quantization parameter value is predicted from the quantization parameter values of the previous CU blocks, and only the quantization parameter difference value is actually encoded.

In the decoder, the inverse quantization parameter difference value is decoded by the inverse quantization parameter difference value derivation unit 122, and the inverse quantization parameter value is calculated by adding the difference value to the inverse quantization parameter value of the block used for prediction.

The quantization parameter value prediction block determination unit 102 and the inverse quantization parameter value prediction block determination unit 123 respectively determine a neighboring block to be referred to when the quantization parameter value of the current block is predicted in the encoder and the decoder.

7A, CUs 710, 711, and 712 located adjacent to the left boundary of the current CU 720 to predict the corresponding values when the quantization / dequantization parameter values are assigned to the CU 720 to be encoded / (Lc, Tc) having the largest block size at each border among the CUs (700, 701, 702; Ta, Tb, Tc) located adjacent to the upper border of the CUs , Maximum value, and so on.

7B is another example of the quantization parameter value prediction block determination unit 102 and the inverse quantization parameter value prediction block determination unit 123 according to the first embodiment of the present invention.

Even when CUs are divided into a plurality of CUs in the LCU and are decoded, a CU having the largest block size among the CUs located adjacent to the current CU 750 to be encoded / decoded is selected at the left boundary and the upper boundary The mean value, the minimum value, and the maximum value of the quantization parameter values used by the two CUs are used to predict the quantization parameter value of the current CU.

8A relates to a quantization parameter value prediction block determination unit 102 and an inverse quantization parameter value prediction block determination unit 123 according to a second embodiment of the present invention.

When predicting the quantization parameter value of the current CU 840 to be encoded / decoded, the CU of the largest block among the CUs adjacent to the periphery of the corresponding CU is referred to. In this case, when there is a large number of CUs of the maximum size, the CU (820; La) positioned at the uppermost position on the left boundary is selected and the CU (800; Ta) positioned on the leftmost position on the upper boundary is selected The average value, the maximum value, and the minimum value of the quantization parameter values of the corresponding CU are used.

8B is another example of the quantization parameter value prediction block determination unit 102 and the inverse quantization parameter value prediction block determination unit 123 according to the second embodiment of the present invention.

Even when the LCU is divided into a plurality of CUs and coded / decoded, the CUs having the largest block size among the CUs located adjacent to the current CU 890 to be encoded / decoded are referred to. In this case, when there are a plurality of CUs having the largest block size at the left boundary, the CU (870; La) located at the uppermost position is used as a reference block. If there are several CUs having the largest block size at the upper boundary, the CU (850; Ta) located at the leftmost neighbor is used as a reference block. After determining the block to be referred to in the left and upward directions, the maximum value, the minimum value, and the average value of the quantization values of the two blocks are obtained, and the quantization parameter values of the CU 890 to be encoded / decoded using the corresponding values are predicted.

9A relates to a quantization parameter value prediction block determination unit 102 and an inverse quantization parameter value prediction block determination unit 123 according to the third embodiment of the present invention.

Tc, La, Lb, and Lc) adjacent to the periphery of the corresponding CU are selected as reference blocks when predicting the quantization parameter values of the current CU 920 to be encoded / decoded . The encoder predicts the quantization parameter value of the CU 920 to be encoded using the maximum value, the minimum value, and the average value of the quantization parameter values of all the referenceable CUs, and then encodes the quantization parameter difference value.

The decoder decodes the inverse quantization parameter value of the CU 920 to be decoded by adding the decoded quantization parameter difference value to the maximum value, the minimum value and the average value of the inverse quantization parameter values of all the CUs that can be referred to.

9B is another example of the quantization parameter value prediction block determination unit 102 and the inverse quantization parameter value prediction block determination unit 123 according to the third embodiment of the present invention.

Lb, Lc, Ta, Tb, Tc) adjacent to the periphery of the corresponding CU, even when the CU (950) for encoding / decoding is located in the LCU, .

The encoder predicts the quantization parameter value of the CU 950 to be encoded based on the average value, the maximum value, the minimum value, and the like of the quantization parameter values of all nearby referenceable CUs, and encodes only the difference value.

When decoding the inverse quantization parameter value of the CU 950 to be decoded, the decoder decodes the inverse quantization parameter value by adding the average value, the maximum value, and the minimum value of the inverse quantization parameter values of all nearby reference CUs.

FIG. 10A relates to a quantization parameter value prediction block determination unit 102 and an inverse quantization parameter value prediction block determination unit 123 according to a fourth embodiment of the present invention.

When the CU 1020 located at the boundary of the LCU is encoded / decoded, the CU 1012 having the largest block size among the reference CUs 1010, 1011, 1012 (La, Lb, Lc) ; Tc). At this time, if there is at least one CU having the largest block size among the CUs that can be referred to at the left boundary, the CU located at the top of the block is selected as a reference block.

The encoder predicts the quantization parameter value of the CU 1020 to be encoded as the quantization parameter value of the CU 1012 (Tc) selected as the reference block at the left boundary, and then encodes the difference value.

The decoder decodes the inverse quantization parameter differential value of the CU 1020 to be decoded and adds the inverse quantization parameter value of the CU 1012 (Tc) selected as the reference block at the left boundary to decode the inverse quantization parameter value.

FIG. 10B is another example of the quantization parameter value prediction block determination unit 102 and the inverse quantization parameter value prediction block determination unit 123 according to the fourth embodiment of the present invention.

When the LCU is divided into a plurality of CUs to be coded / decoded, the largest block size among the CUs 1030, 1031, 1032 (La, Lb, Lc) positioned adjacent to the left border of the CU 1050 to be coded / (CU 1030; At this time, if there is at least one CU having the largest block size at the left boundary, the CU 1030 (La) positioned at the uppermost position among the blocks is selected as a reference block.

The encoder predicts the quantization parameter value of the CU 1050 to be encoded with the quantization parameter value of the CU 1030 (La) selected as the reference block at the left boundary, and then encodes the difference value.

The decoder decodes the inverse quantization parameter difference value of the CU 1050 to be decoded and adds the inverse quantization parameter value of the CU 1030 (La) selected as the reference block at the left boundary to decode the inverse quantization parameter value.

11A relates to a quantization parameter value prediction block determination unit 102 and an inverse quantization parameter value prediction block determination unit 123 according to a fifth embodiment of the present invention.

When reference is made to the CU 1120 located at the boundary of the LCU, all referenceable CUs 1110, 1111, 1112 (La, Lb, Lc) adjacent to the left boundary of the corresponding CU are used as reference blocks.

The encoder predicts the quantization parameter value of the CU 1120 to be encoded using the average value, the maximum value, and the minimum value of the quantization parameter values of the referenceable CUs 1110, 1111, 1112 (La, Lb, Lc) And only the difference value is encoded.

The decoder decodes the inverse quantization parameter difference value of the CU 1120 to be decoded and then calculates the average value of the inverse quantization parameter values of the referenceable CUs 1110, 1111, 1112 (La, Lb, Lc) , The minimum value, and the like, thereby decoding the inverse quantization parameter value of the CU 1120 to be decoded.

11B is another example of the quantization parameter value prediction block determination unit 102 and the inverse quantization parameter value prediction block determination unit 123 according to the fifth embodiment of the present invention.

When the LCU is divided into a plurality of CUs to be encoded / decoded, all the referenceable CUs located adjacent to the left boundary of the CU 1150 to be encoded / decoded are used as reference blocks.

The encoder predicts the quantization parameter value of the CU 1150 to be encoded with an average value, a minimum value, a maximum value, etc. of the quantization parameter values of all referenceable CUs located adjacent to the left boundary, and then codes the difference value.

The decoder decodes the inverse quantization parameter difference value of the CU 1150 to be decoded and adds the average value, the minimum value, and the maximum value of the quantization parameter values of all the reference CUs located adjacent to the left boundary to obtain the inverse quantization parameter value .

Claims (12)

Determining whether an encoding block has an inverse quantization difference value; if the encoding block is determined to have an inverse quantization difference value, a parameter related to whether or not an inverse quantization difference value is encoded is set to a first value;
Decoding flag information indicating whether the encoding block is divided into a plurality of subblocks, the plurality of subblocks being four subblocks;
Obtaining an inverse quantization difference value for the encoding block; if the parameter has the first value and the encoding block is divided into a plurality of subblocks, , The parameter is changed from the first value to the second value and the parameter is changed to the second value when the inverse quantization difference value is decoded for the first sub- Thereafter, the inverse quantization difference value is not decoded for the remaining subblocks except for the first subblock;
Obtaining an inverse quantization parameter prediction value using a neighboring block of the encoding block, the neighboring block being determined using position information of a neighboring block located in the vicinity of the encoding block, And an upper neighboring block located on the upper side of the encoding block; And
And obtaining the inverse quantization parameter using the inverse quantization difference value and the inverse quantization parameter prediction value. The method according to claim 1,
Wherein the inverse quantization parameter predicted value is obtained by:
The inverse quantization parameter of the left neighboring block and the inverse quantization parameter of the upper neighboring block. 3. The method of claim 2,
Wherein the inverse quantization parameter prediction value is derived based on an inverse quantization parameter of the left neighboring block and an average value of the inverse quantization parameters of the upper neighboring block. The method according to claim 1,
Whether or not the encoded block has an inverse quantization difference value is determined based on the inverse-
Wherein the minimum coding block size and the maximum coding block size are determined based on the minimum coding block size and the maximum coding block size. A step of determining whether or not an inverse quantization difference value is to be encoded for a current block to be coded; a step of determining whether or not an inverse quantization difference value is to be encoded for the current block, Lt; / RTI >
Determining whether the current block to be coded is divided into a plurality of sub-blocks, the plurality of sub-blocks being four sub-blocks;
Acquiring an inverse quantization parameter predicted value using a neighboring block of the current block, determining the neighboring block using position information of a neighboring block located in the vicinity of the current block, A left neighboring block located on the left side of the block and an upper neighboring block located on the upper side of the current block;
Obtaining an inverse quantization difference value for the current block using the inverse quantization parameter and the inverse quantization parameter prediction value; And
And encoding the inverse quantization difference value for the current block, if the parameter has the first value and the current block is divided into a plurality of subblocks, Block is encoded, and when the inverse quantization difference value is encoded for the first sub-block, the parameter is changed from the first value to a second value, and the parameter is changed from the second value The inverse quantization difference value is not encoded for the remaining subblocks except for the first subblock,
/ RTI > 6. The method of claim 5,
Wherein the inverse quantization parameter predicted value is obtained by:
The inverse quantization parameter of the left neighboring block, and the inverse quantization parameter of the upper neighboring block. The method according to claim 6,
Wherein the inverse quantization parameter prediction value is derived based on an inverse quantization parameter of the left neighboring block and an average value of the inverse quantization parameter of the upper neighboring block. 6. The method of claim 5,
Wherein whether or not the inverse quantization difference value is to be encoded with respect to the current block,
Wherein the minimum coding block size and the maximum coding block size are determined based on the minimum coding block size and the maximum coding block size. A recording medium storing a bitstream generated by a video encoding method,
A step of determining whether or not an inverse quantization difference value is to be encoded for a current block to be coded; a step of determining whether or not an inverse quantization difference value is to be encoded for the current block, Lt; / RTI >
Determining whether the current block to be coded is divided into a plurality of sub-blocks, the plurality of sub-blocks being four sub-blocks;
Acquiring an inverse quantization parameter predicted value using a neighboring block of the current block, determining the neighboring block using position information of a neighboring block located in the vicinity of the current block, A left neighboring block located on the left side of the block and an upper neighboring block located on the upper side of the current block;
Obtaining an inverse quantization difference value for the current block using the inverse quantization parameter and the inverse quantization parameter prediction value; And
And encoding the inverse quantization difference value for the current block, if the parameter has the first value and the current block is divided into a plurality of subblocks, Block is encoded, and when the inverse quantization difference value is encoded for the first sub-block, the parameter is changed from the first value to a second value, and the parameter is changed from the second value The inverse quantization difference value is not encoded for the remaining subblocks except for the first subblock,
And stores the bit stream. 10. The method of claim 9,
Wherein the inverse quantization parameter predicted value is obtained by:
The inverse quantization parameter of the left neighboring block and the inverse quantization parameter of the upper neighboring block. 11. The method of claim 10,
Wherein the inverse quantization parameter prediction value is derived based on an inverse quantization parameter of the left neighboring block and an average value of the inverse quantization parameter of the upper neighboring block. 10. The method of claim 9,
Wherein whether or not the inverse quantization difference value is to be encoded with respect to the current block,
And the size of the minimum encoding block and the size of the maximum encoding block.

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