WO2019150411A1

WO2019150411A1 - Video encoding device, video encoding method, video decoding device, and video decoding method, and video encoding system

Info

Publication number: WO2019150411A1
Application number: PCT/JP2018/002811
Authority: WO
Inventors: 幸二山田; 中川　章
Original assignee: 富士通株式会社
Priority date: 2018-01-30
Filing date: 2018-01-30
Publication date: 2019-08-08

Abstract

A first encoding unit encodes a block to be encoded in an image included in video. A determination unit generates a first difference motion vector from a motion vector and a predicted motion vector with respect to the block to be encoded. Next, the determination unit changes a sign indicating whether a component of the first difference motion vector is positive or negative so as to generate a plurality of difference motion vector candidates, and determines a second difference motion vector from among the difference motion vector candidates. In this case, the determination unit determines the second difference motion vector by using a local decoding pixel value of an encoded pixel adjacent to the block to be encoded and a local decoding pixel value of an encoded pixel included in each of a plurality of reference block candidates indicated by the plurality of difference motion vector candidates. A generation unit generates matching information indicating whether the sign of the component of the first difference motion vector matches the sign of the component of the second difference motion vector. A second encoding unit encodes the absolute value of the component of the first difference motion vector and the matching information.

Description

Video encoding apparatus, video encoding method, video decoding apparatus, video decoding method, and video encoding system

The present invention relates to a video encoding device, a video encoding method, a video decoding device, a video decoding method, and a video encoding system.

International Telecommunication Union Telecommunication Standardization Sector (ITU-T) H.265 defines High Efficiency Video Coding (HEVC), which is the latest video coding standard. In HEVC, context-adaptive binary arithmetic coding (CABAC), which has a high processing load but high compression efficiency, is adopted as a variable-length coding method.

Also, in HEVC, two prediction methods, inter prediction and intra prediction, are adopted as prediction methods for encoding a block to be encoded using information on encoded blocks. Inter prediction is a prediction method that uses a pixel value of a block (reference block) that is temporally close to the encoding target block, and intra prediction is a pixel value of a block that is close in distance to the encoding target block. The prediction method used.

In inter prediction, a motion vector indicating a reference block is generated. The motion vector includes a horizontal component (x component) and a vertical component (y component) in the image at each time included in the video.

The motion vector for the encoding target block often has a high correlation with the motion vectors for the blocks around the encoding target block. Therefore, in HEVC, a predicted motion vector, which is a predicted value of a motion vector of an encoding target block, is obtained from the motion vectors of surrounding blocks, and is a difference between the actual motion vector of the encoding target block and the predicted motion vector. A differential motion vector is generated. By encoding this differential motion vector, the amount of motion vector coding can be compressed.

In addition, standardization activities for Future Video Coding (FVC), which is the next video coding standard, are being conducted, and further improvements in compression efficiency are being studied.

There is also known a moving image coding apparatus that reduces the amount of difference vectors encoded in motion vector prediction (see, for example, Patent Document 1).

JP 2012-235278 A

In HEVC, the syntax of a differential motion vector in inter prediction is encoded by CABAC. However, the code amount of the flag indicating the sign (positive or negative) of each component of the differential motion vector is not sufficiently compressed.

Note that such a problem occurs not only in video coding using HEVC but also in other video coding using inter prediction.

In one aspect, an object of the present invention is to reduce a code amount accompanying a motion vector in video encoding.

In one proposal, the video encoding device includes a first encoding unit, a determination unit, a generation unit, and a second encoding unit.

The first encoding unit encodes the encoding target block in the image included in the video. The determination unit generates a first differential motion vector from the motion vector for the encoding target block and the predicted motion vector for the encoding target block.

Next, the determination unit generates a plurality of differential motion vector candidates including the first differential motion vector by changing a sign indicating whether the component of the first differential motion vector is positive or negative. The second differential motion vector is determined from among the differential motion vector candidates. At this time, the determination unit includes the locally decoded pixel values of the encoded pixels adjacent to the encoding target block and the locally decoded pixels of the encoded pixels included in each of the plurality of reference block candidates indicated by the plurality of differential motion vector candidates. The second difference motion vector is determined using the value.

The generating unit generates coincidence information indicating whether or not the code of the component of the first differential motion vector matches the code of the component of the second differential motion vector. The second encoding unit encodes the absolute value of the first differential motion vector component and the coincidence information.

According to the embodiment, it is possible to reduce a code amount accompanying a motion vector in video encoding.

It is a functional block diagram of a video coding apparatus. It is a flowchart of a video encoding process. It is a functional block diagram of a video decoding apparatus. It is a flowchart of a video decoding process. It is a figure which shows a difference motion vector. It is a figure which shows a difference motion vector candidate and a reference block candidate. It is a functional block diagram which shows the specific example of a video coding apparatus. It is a 1st functional block diagram of an arithmetic coding part. It is a figure which shows the 1st calculation method of an estimated difference motion vector. It is a figure which shows the 2nd calculation method of an estimated difference motion vector. It is a figure which shows the 3rd calculation method of an estimated difference motion vector. It is a figure which shows the calculation method of a prediction pixel value. It is a flowchart which shows the specific example of a video encoding process. It is a flowchart of a 1st code flag production | generation process. It is a flowchart of the 2nd code flag generation processing. It is a flowchart of a 3rd code flag production | generation process. It is a functional block diagram which shows the specific example of a video decoding apparatus. It is a 1st functional block diagram of an arithmetic decoding part. It is a flowchart which shows the specific example of a video decoding process. It is a flowchart of a 1st motion vector production | generation process. It is a flowchart of the 2nd motion vector generation processing. It is a flowchart of a 3rd motion vector generation process. It is a figure which shows a motion vector candidate and a reference block candidate. It is a 2nd functional block diagram of an arithmetic coding part. It is a flowchart of the 4th code flag generation processing. It is a flowchart of the 5th code flag generation processing. It is a flowchart of the 6th code flag generation processing. It is a 2nd functional block diagram of an arithmetic decoding part. It is a flowchart of a 4th motion vector generation process. It is a flowchart of a 5th motion vector generation process. It is a flowchart of a 6th motion vector generation process. It is a functional block diagram of a video coding system. It is a block diagram of information processing apparatus.

Hereinafter, embodiments will be described in detail with reference to the drawings.
The processing procedure of CABAC adopted in HEVC is as follows.
(1) Binarization Among the encoding target syntax elements, a multilevel syntax element is converted into a binary signal (bin) to be arithmetically encoded.

(2) Context modeling For each bin of syntax elements, an occurrence probability model used for arithmetic coding is determined in accordance with other syntax elements or values of syntax elements adjacent to a region to be encoded. . In this case, the occurrence probability of each value of logic “0” and logic “1” is variable.
On the other hand, for bins whose occurrence probabilities are difficult to estimate, a bypass mode is selected in which the occurrence probabilities of the values of logic “0” and logic “1” are fixed to 0.5.
(3) Arithmetic coding Based on the occurrence probability of the occurrence symbol, a real number straight line of 0 or more and less than 1 is sequentially divided into sections, and finally a code word in binary notation is generated from the real number indicating the divided section. Is done.

In arithmetic coding in bypass mode, code amount is not compressed. However, since the probability estimation process is skipped and the amount of computation of the real line segmentation process is reduced, the encoding process is speeded up and the memory area for storing the occurrence probability is reduced.

The syntax of the differential motion vector in HEVC includes a flag indicating the sign (positive or negative) of the x component and the y component of the differential motion vector. The flag indicating the sign of the x component is mvd_sign_flag [0], and the flag indicating the sign of the y component is mvd_sign_flag [1]. The values of these flags are specified as follows.

mvd_sign_flag [0]
0: When the sign of the x component of the difference motion vector is positive 1: When the sign of the x component of the difference motion vector is negative mvd_sign_flag [1]
0: When the sign of the y component of the differential motion vector is positive 1: When the sign of the y component of the differential motion vector is negative

However, since it is difficult to predict the probability that the sign of the x component and the y component of the differential motion vector will be positive or negative, in CABAC, a flag indicating the sign of the x component and the y component is encoded in the bypass mode. For this reason, the code amount of these flags is not compressed.

FIG. 1 shows an example of the functional configuration of the video encoding apparatus according to the embodiment. The video encoding device 101 of FIG. 1 includes a first encoding unit 111, a determination unit 112, a generation unit 113, and a second encoding unit 114.

FIG. 2 is a flowchart showing an example of video encoding processing performed by the video encoding device 101 of FIG. First, the first encoding unit 111 encodes an encoding target block in an image included in the video (step 201). Next, the determination unit 112 generates a first differential motion vector from the motion vector for the encoding target block and the predicted motion vector for the encoding target block (step 202).

Next, the determination unit 112 generates a plurality of differential motion vector candidates including the first differential motion vector by changing a sign indicating whether the component of the first differential motion vector is positive or negative ( Step 203). Then, the determination unit 112 determines a second differential motion vector from among these differential motion vector candidates (step 204). At this time, the determination unit 112 performs local decoding of the encoded pixel included in each of the plurality of reference block candidates indicated by the plurality of reference motion vector candidates and the local decoded pixel value of the encoded pixel adjacent to the encoding target block. A second differential motion vector is determined using the pixel value.

Next, the generation unit 113 generates coincidence information indicating whether or not the code of the first differential motion vector component matches the code of the second differential motion vector component (step 205). Then, the second encoding unit 114 encodes the absolute value of the first differential motion vector component and the coincidence information (step 206).

FIG. 3 shows a functional configuration example of the video decoding apparatus according to the embodiment. 3 includes a first decoding unit 311, a determination unit 312, a generation unit 313, and a second decoding unit 314.

FIG. 4 is a flowchart showing an example of video decoding processing performed by the video decoding device 301 in FIG. First, the first decoding unit 311 decodes the encoded video, and restores the absolute value of the first differential motion vector component for the decoding target block in the image included in the encoded video (step 401). At this time, the first decoding unit 311 matches information indicating whether the code indicating whether the component of the first difference motion vector is positive or negative matches the code of the component of the second difference motion vector. Are restored together with the absolute values of the components of the first differential motion vector.

Next, the determination unit 312 generates a plurality of differential motion vector candidates by adding codes to the absolute values of the components of the first differential motion vector (step 402). Then, the determination unit 312 determines a second differential motion vector from among these differential motion vector candidates (step 403). At this time, the determination unit 312 uses the decoded pixel value of the pixel adjacent to the decoding target block and the decoded pixel value of the pixel included in each of the plurality of reference block candidates indicated by the plurality of differential motion vector candidates, A differential motion vector is determined.

Next, the generation unit 313 generates a first differential motion vector from the second differential motion vector based on the match information (step 404). Then, the generation unit 313 generates a motion vector for the decoding target block from the first differential motion vector and the predicted motion vector for the decoding target block (step 405).

Next, the second decoding unit 314 decodes the coefficient information of the decoding target block using the motion vector for the decoding target block (step 406).

1 and the video decoding apparatus 301 in FIG. 3 can reduce the amount of code associated with a motion vector in video encoding.

FIG. 5 shows an example of the difference motion vector. A reference image 501 in FIG. 5 is a locally decoded image of an image encoded before the encoding target image. The reference image 501 includes a block 511 that exists at the same position as the encoding target block in the encoding target image, and a reference block 512 for the encoding target block.

The motion vector 521 for the encoding target block is a vector from the block 511 to the reference block 512, and is obtained by motion search processing. On the other hand, the prediction vector 522 is obtained from the motion vectors for the blocks around the encoding target block, and the difference motion vector 523 represents the difference between the motion vector 521 and the prediction vector 522.

FIG. 6 shows examples of differential motion vector candidates and reference block candidates. In the reference image 501 of FIG. 6, the direction from left to right is the positive direction of the x coordinate, and the direction from top to bottom is the positive direction of the y coordinate.

In this case, based on the four combinations of the positive sign and negative sign of the x component and the positive sign and negative sign of the y component of the difference motion vector 523 in FIG. Motion vector candidates 614 are generated. The four combinations of the x component code and the y component code are as follows.
(Sign of x component, sign of y component) = (positive, positive)
(Sign of x component, sign of y component) = (positive, negative)
(Sign of x component, sign of y component) = (negative, negative)
(Sign of x component, sign of y component) = (negative, positive)

The difference motion vector candidate 611 is a vector from the end point of the prediction vector 522 toward the reference block candidate 601, and the x component and the y component of the difference motion vector candidate 611 are positive. The difference motion vector candidate 612 is a vector from the end point of the prediction vector 522 toward the reference block candidate 602, and the x component of the difference motion vector candidate 612 is positive and the y component is negative.

The difference motion vector candidate 613 is a vector from the end point of the prediction vector 522 toward the reference block candidate 603, and the x component and the y component of the difference motion vector candidate 613 are negative. The difference motion vector candidate 614 is a vector from the end point of the prediction vector 522 toward the reference block candidate 604, and the x component of the difference motion vector candidate 614 is negative and the y component is positive.

FIG. 7 shows a specific example of the video encoding device 101 of FIG. 7 includes a block division unit 711, a prediction error generation unit 712, an orthogonal transformation unit 713, a quantization unit 714, an arithmetic coding unit 715, and an encoding control unit 716. Furthermore, the video encoding device 701 includes an intra-frame prediction unit 717, an inter-frame prediction unit 718, a selection unit 719, an inverse quantization unit 720, an inverse orthogonal transform unit 721, a reconstruction unit 722, an in-loop filter 723, and a memory 724. including.

A prediction error generation unit 712, an orthogonal transform unit 713, a quantization unit 714, an intra-frame prediction unit 717, an inter-frame prediction unit 718, a selection unit 719, an inverse quantization unit 720, an inverse orthogonal transform unit 721, a reconstruction unit 722, and The in-loop filter 723 corresponds to the first encoding unit 111 in FIG.

The video encoding device 701 can be implemented as a hardware circuit, for example. In this case, each component of the video encoding device 701 may be mounted as an individual circuit or may be mounted as one integrated circuit.

The video encoding device 701 encodes the input video to be encoded, and outputs the encoded video as an encoded stream. The video encoding device 701 can transmit the encoded stream to the video decoding device 301 in FIG. 3 via a communication network.

The encoding target video includes a plurality of images corresponding to a plurality of times. The image at each time corresponds to the image to be encoded and may be called a picture or a frame. Each image may be a color image or a monochrome image. In the case of a color image, the pixel value may be in RGB format or YUV format.

The block division unit 711 divides the encoding target image into a plurality of blocks, and outputs the original image of the encoding target block to the prediction error generation unit 712, the intra-frame prediction unit 717, and the inter-frame prediction unit 718.

The intra-frame prediction unit 717 performs intra prediction on the encoding target block, and outputs a prediction image of intra prediction to the selection unit 719. The inter-frame prediction unit 718 performs inter prediction on the encoding target block, and outputs a predicted image of inter prediction to the selection unit 719. At this time, the inter-frame prediction unit 718 obtains a motion vector for the encoding target block by the motion search process, and outputs the obtained motion vector to the arithmetic coding unit 715.

The selection unit 719 selects a prediction image output by either the intra-frame prediction unit 717 or the inter-frame prediction unit 718, and outputs the prediction image to the prediction error generation unit 712 and the reconstruction unit 722. The prediction error generation unit 712 outputs the difference between the prediction image output from the selection unit 719 and the original image of the encoding target block to the orthogonal transformation unit 713 as a prediction error.

The orthogonal transform unit 713 performs orthogonal transform on the prediction error output from the prediction error generation unit 712, and outputs a transform coefficient to the quantization unit 714. The quantization unit 714 quantizes the transform coefficient and outputs the quantization coefficient to the arithmetic coding unit 715 and the inverse quantization unit 720.

The arithmetic encoding unit 715 encodes the quantized coefficient output from the quantizing unit 714 and the motion vector output from the inter-frame prediction unit 718 using CABAC, and outputs an encoded stream. Then, the arithmetic encoding unit 715 outputs the amount of information generated by CABAC to the encoding control unit 716.

The inverse quantization unit 720 performs inverse quantization on the quantization coefficient output from the quantization unit 714, generates an inverse quantization coefficient, and outputs the generated inverse quantization coefficient to the inverse orthogonal transform unit 721. . The inverse orthogonal transform unit 721 performs inverse orthogonal transform on the inverse quantization coefficient, generates a prediction error, and outputs the generated prediction error to the reconstruction unit 722.

The reconstruction unit 722 adds the prediction image output from the selection unit 719 and the prediction error output from the inverse orthogonal transform unit 721 to generate a reconstruction image, and the generated reconstruction image is converted into the in-loop filter 723 and Output to the memory 724. The in-loop filter 723 performs a filtering process such as a deblocking filter on the reconstructed image output from the reconstructing unit 722 to generate a local decoded image, and outputs the generated local decoded image to the memory 724.

The memory 724 stores the reconstructed image output from the reconstructing unit 722 as a locally decoded image and also stores the locally decoded image output from the in-loop filter 723. The locally decoded image stored in the memory 724 is output to the intra-frame prediction unit 717, the inter-frame prediction unit 718, and the arithmetic coding unit 715. The intra-frame prediction unit 717 uses the local decoded pixel value included in the local decoded image as a reference pixel value for the subsequent block, and the inter-frame prediction unit 718 uses the local decoded image as a reference image for the subsequent image.

The encoding control unit 716 determines a quantization parameter (QP) so that the information amount output from the arithmetic encoding unit 715 becomes the target information amount, and outputs the determined QP to the quantization unit 714.

FIG. 8 shows a first functional configuration example of the arithmetic encoding unit 715 of FIG. 8 includes a determination unit 801, a generation unit 802, and an encoding unit 803. The determination unit 801 includes a difference motion vector calculation unit 811, a difference motion vector candidate calculation unit 812, and an estimated difference motion vector calculation unit 813. The determination unit 801, the generation unit 802, and the encoding unit 803 correspond to the determination unit 112, the generation unit 113, and the second encoding unit 114 in FIG.

The difference motion vector calculation unit 811 calculates a difference motion vector representing a difference between the motion vector output from the inter-frame prediction unit 718 and the prediction motion vector for the encoding target block. The predicted motion vector is obtained from the motion vectors for the blocks around the encoding target block by the inter-frame prediction unit 718 or the differential motion vector calculation unit 811.

The difference motion vector candidate calculation unit 812 generates four difference motions based on four combinations of the positive sign and negative sign of the x component of the difference motion vector and the positive sign and negative sign of the y component. Calculate vector candidates.

The estimated difference motion vector calculation unit 813 obtains four reference block candidates corresponding to each of the four difference motion vector candidates. Then, the estimated difference motion vector calculation unit 813 obtains the local decoded pixel value of the encoded pixel adjacent to the encoding target block and the local decoded pixel value of the encoded pixel included in each of the four reference block candidates. To calculate an estimated differential motion vector.

In this case, since the estimated difference motion vector is calculated by a calculation method different from the motion search process in the inter-frame prediction unit 718, it does not always match the difference motion vector calculated by the difference motion vector calculation unit 811.

The generation unit 802 generates a code flag indicating whether or not the code of each component of the differential motion vector matches the code of each component of the estimated differential motion vector. The encoding unit 803 encodes the absolute value and sign flag of each component of the differential motion vector and the quantization coefficient output by the quantization unit 714 using CABAC context modeling using a variable occurrence probability. The sign flag of each component corresponds to the coincidence information.

As the sign flag, mvd_sign_flag [0] and mvd_sign_flag [1] described above can be used. However, the values of these sign flags are changed as follows.

mvd_sign_flag [0]
0: When the sign of the x component of the difference motion vector is the same as the sign of the x component of the estimated difference motion vector 1: When the sign of the x component of the difference motion vector is different from the sign of the x component of the estimated difference motion vector mvd_sign_flag [1]
0: When the sign of the y component of the difference motion vector is the same as the sign of the y component of the estimated difference motion vector 1: When the sign of the y component of the difference motion vector is different from the sign of the y component of the estimated difference motion vector

In this way, the sign flag does not directly indicate the positive or negative sign of each component of the difference motion vector, but instead shows the difference between the sign of each component of the difference motion vector and the sign of each component of the estimated difference motion vector. Show. As a result, the occurrence probability of the value “0” indicating that the two codes are the same can be made higher than the occurrence probability of the value “1” indicating that the two codes are different. Therefore, the code flag can be encoded by arithmetic encoding using context modeling, and the code amount of the code flag is reduced.

FIG. 9 shows an example of a first calculation method of the estimated difference motion vector. An encoding target block 903 is included in the area 902 of the encoding target image 901. First, the estimated difference motion vector calculation unit 813 acquires the local decoded pixel value of the encoded pixel 911 adjacent to the encoding target block 903 in the region 902.

Next, the estimated difference motion vector calculation unit 813 arranges each reference block candidate 904 so as to overlap the position of the encoding target block 903 in the region 902, and locally decodes the encoded pixels included in the reference block candidate 904. Get the value. For example, the estimated difference motion vector calculation unit 813 can acquire the locally decoded pixel value of the encoded pixel 912 in the reference block candidate 904 adjacent to the encoded pixel 911.

Next, the estimated difference motion vector calculation unit 813 performs local decoding of the encoded pixel 912 with respect to the statistical value A0 of the local decoded pixel value of the encoded pixel 911 and the i-th (i = 1 to 4) reference block candidate. The statistical value Ai of the pixel value is calculated. As the statistical value A0 and the statistical value Ai, an average value, median value, mode value, and the like of a plurality of local decoded pixel values can be used.

Then, the estimated difference motion vector calculation unit 813 determines the estimated difference motion vector by comparing the statistical value A0 and the statistical value Ai. For example, the estimated difference motion vector calculation unit 813 obtains a reference block candidate having a statistical value closest to the statistical value A0 among the statistical values A1 to A4, and estimates a differential motion vector candidate indicating the obtained reference block candidate. A differential motion vector can be determined.

FIG. 10 shows an example of a second calculation method of the estimated difference motion vector. The estimated difference motion vector calculation unit 813 calculates the absolute difference value of the local decoded pixel values of the two pixels for the pair 1001 of the encoded pixel 911 and the encoded pixel 912. Then, the estimated difference motion vector calculation unit 813 calculates the difference absolute value sum by accumulating the difference absolute values for a plurality of pairs on the upper boundary and the left boundary of the encoding target block 903.

Next, the estimated difference motion vector calculation unit 813 determines the estimated difference motion vector by comparing the four difference absolute value sums with respect to each of the four reference block candidates. For example, the estimated difference motion vector calculation unit 813 can obtain a reference block candidate having the smallest sum of absolute differences, and can determine a difference motion vector candidate indicating the obtained reference block candidate as an estimated difference motion vector.

FIG. 11 shows an example of the third calculation method of the estimated difference motion vector. The estimated difference motion vector calculation unit 813 selects a combination 1101 of four encoded pixels in the vicinity of the boundary of the encoding target block 903. The combination 1101 includes an encoded pixel 1111 to an encoded pixel 1114.

The encoded pixel 1111 and the encoded pixel 1112 are pixels included in the region 902 of the encoding target image 901. The encoded pixel 1112 is adjacent to the boundary of the encoding target block 903, and the encoded pixel 1111 is present. Is adjacent to the encoded pixel 1112. On the other hand, the encoded pixel 1113 and the encoded pixel 1114 are pixels included in the reference block candidate 904, the encoded pixel 1113 is adjacent to the boundary of the encoding target block 903, and the encoded pixel 1114 is encoded. Adjacent to the converted pixel 1113.

The estimated difference motion vector calculation unit 813 calculates a predicted pixel value on the boundary of the encoding target block 903 from the locally decoded pixel values of the encoded pixel 1111 and the encoded pixel 1112. Further, the estimated difference motion vector calculation unit 813 calculates a predicted pixel value on the boundary of the encoding target block 903 from the locally decoded pixel values of the encoded pixel 1113 and the encoded pixel 1114.

FIG. 12 shows an example of a method for calculating a predicted pixel value on the boundary of the encoding target block 903. The horizontal axis in FIG. 12 represents the y axis of the encoding target image 901, and the vertical axis represents the pixel value.

The estimated difference motion vector calculation unit 813 sets the y coordinate y1 of the boundary of the encoding target block 903 on the straight line 1201 that passes through the local decoded pixel value of the encoded pixel 1111 and the local decoded pixel value of the encoded pixel 1112. The corresponding pixel value p1 is obtained as the predicted pixel value. Also, the estimated difference motion vector calculation unit 813 predicts a pixel value p2 corresponding to y1 on a straight line 1202 that passes through the local decoded pixel value of the encoded pixel 1113 and the local decoded pixel value of the encoded pixel 1114. Obtained as a pixel value.

Next, the estimated difference motion vector calculation unit 813 calculates a difference absolute value 1203 between the predicted pixel value p1 and the predicted pixel value p2. Then, the estimated difference motion vector calculation unit 813 accumulates the difference absolute values 1203 for a plurality of combinations on the upper boundary and the left boundary of the encoding target block 903, and calculates a difference absolute value sum.

According to the first to third calculation methods of the estimated difference motion vector, it is possible to obtain an estimated difference motion vector that is highly likely to match the difference motion vector with a smaller calculation amount than the motion search processing in the inter-frame prediction unit 718. Can do. As a result, the occurrence probability of the value “0” in the sign flag can be made higher than the occurrence probability of the value “1”.

FIG. 13 is a flowchart showing a specific example of the video encoding process performed by the video encoding device 701 in FIG. First, the intra-frame prediction unit 717 performs intra prediction on the encoding target block (step 1301), and the inter-frame prediction unit 718 performs inter prediction on the encoding target block (step 1302).

Next, the prediction error generation unit 712, the orthogonal transformation unit 713, and the quantization unit 714 code the encoding target block using the prediction image output from either the intra-frame prediction unit 717 or the inter-frame prediction unit 718. To generate a quantized coefficient (step 1303). Then, the determination unit 801 and the generation unit 802 of the arithmetic encoding unit 715 generate a code flag for the differential motion vector of the encoding target block (step 1304).

Next, the video encoding device 701 determines whether or not the encoding of the encoding target image has been completed (step 1305). When an unprocessed block remains (step 1305, NO), the video encoding device 701 repeats the processing after step 1301 for the next block.

On the other hand, when the encoding of the encoding target image is completed (step 1305, YES), the encoding unit 803 of the arithmetic encoding unit 715 performs variable length encoding on the quantization coefficient and the prediction mode information (step 1306). . The prediction mode information includes the absolute value and sign flag of each component of the differential motion vector.

Next, the video encoding device 701 determines whether or not the encoding of the encoding target video has been completed (step 1307). When an unprocessed image remains (step 1307, NO), the video encoding device 701 repeats the processing after step 1301 for the next image. Then, when encoding of the encoding target video is completed (step 1307, YES), the video encoding device 701 ends the process.

FIG. 14 is a flowchart showing an example of the first code flag generation process in step 1304 of FIG. In the first code flag generation process, the estimated difference motion vector is calculated by the first calculation method shown in FIG.

First, the difference motion vector calculation unit 811 of the determination unit 801 calculates a difference motion vector from the motion vector and the predicted motion vector (step 1401). The difference motion vector candidate calculation unit 812 then calculates four difference motion vector candidates based on the four combinations of the x and y component codes of the difference motion vector (step 1402).

Next, the estimated difference motion vector calculation unit 813 obtains four reference block candidates indicated by each of the four difference motion vector candidates (step 1403).

Next, the estimated difference motion vector calculation unit 813 calculates a statistical value A0 of the locally decoded pixel value of the encoded pixel adjacent to the encoding target block in the encoding target image (step 1404).

Next, the estimated difference motion vector calculation unit 813 encodes the reference block candidate adjacent to the encoded pixel used in step 1404 when each reference block candidate is arranged at the position of the encoding target block. A completed pixel is identified (step 1405). Then, the estimated difference motion vector calculation unit 813 calculates the statistical value Ai (i = 1 to 4) of the locally decoded pixel value of the identified encoded pixel.

Next, the estimated difference motion vector calculation unit 813 obtains a reference block candidate having a statistical value closest to the statistical value A0 among the statistical values A1 to A4, and obtains a differential motion vector candidate indicating the obtained reference block candidate. The estimated difference motion vector is determined (step 1406).

Next, the generation unit 802 compares the code of each component of the differential motion vector and the code of each component of the estimated differential motion vector to determine the value of the code flag of each component (step 1407). If the code of the component of the differential motion vector and the code of the component of the estimated differential motion vector are the same, the value of the code flag of that component is determined to be “0”, and if the two codes are different, the code flag of that component The value of is determined to be “1”.

FIG. 15 is a flowchart showing an example of the second code flag generation process in step 1304 of FIG. In the second code flag generation process, the estimated difference motion vector is calculated by the second calculation method shown in FIG. The processing in steps 1501 to 1503 and step 1506 in FIG. 15 is the same as the processing in steps 1401 to 1403 and step 1407 in FIG.

In step 1504, the estimated difference motion vector calculation unit 813, when each reference block candidate is arranged at the position of the encoding target block, is adjacent to the surrounding encoded pixels in the encoding target image. Identify encoded pixels in the candidate. Then, the estimated difference motion vector calculation unit 813, for each reference block candidate, the local decoded pixel value of the surrounding encoded pixel in the encoding target image and the local decoded pixel value of the encoded pixel in the reference block candidate The sum of absolute differences is calculated.

Next, the estimated difference motion vector calculation unit 813 obtains a reference block candidate having the smallest sum of absolute differences among the four reference block candidates, and obtains a difference motion vector candidate indicating the obtained reference block candidate as an estimated difference. A motion vector is determined (step 1505).

FIG. 16 is a flowchart showing an example of the third code flag generation process in step 1304 of FIG. In the third code flag generation process, the estimated difference motion vector is calculated by the third calculation method shown in FIG. The processing in steps 1601 to 1603 and step 1606 in FIG. 16 is the same as the processing in steps 1401 to 1403 and step 1407 in FIG.

In step 1604, the estimated difference motion vector calculation unit 813 identifies two columns of encoded pixels in the encoding target image that are adjacent to the outside of the boundary of the encoding target block. Then, the estimated difference motion vector calculation unit 813 calculates a predicted pixel value on the boundary of the encoding target block from the locally decoded pixel values of the two columns of encoded pixels.

Next, the estimated difference motion vector calculation unit 813 has two columns in the reference block candidate that are adjacent to the inside of the boundary of the encoding target block when the reference block candidates are arranged so as to overlap the position of the encoding target block. The encoded pixels are identified. Then, the estimated difference motion vector calculation unit 813 calculates a predicted pixel value on the boundary of the encoding target block from the locally decoded pixel values of the two columns of encoded pixels.

Next, the estimated difference motion vector calculation unit 813, for each reference block candidate, the predicted pixel value calculated from the encoded pixel in the encoding target image and the predicted pixel calculated from the encoded pixel in the reference block candidate Calculate the sum of absolute differences from the value.

Next, the estimated difference motion vector calculation unit 813 obtains a reference block candidate having the smallest sum of absolute differences among the four reference block candidates, and obtains a difference motion vector candidate indicating the obtained reference block candidate as an estimated difference. A motion vector is determined (step 1605).

FIG. 17 shows a specific example of the video decoding device 301 in FIG. 17 includes an arithmetic decoding unit 1711, an inverse quantization unit 1712, an inverse orthogonal transform unit 1713, a reconstruction unit 1714, an in-loop filter 1715, an intra-frame prediction unit 1716, a motion compensation unit 1717, and a selection unit 1718. , And a memory 1719.

An inverse quantization unit 1712, an inverse orthogonal transform unit 1713, a reconstruction unit 1714, an in-loop filter 1715, an intra-frame prediction unit 1716, a motion compensation unit 1717, and a selection unit 1718 correspond to the second decoding unit 314 in FIG. .

The video decoding device 1701 can be implemented as a hardware circuit, for example. In this case, each component of the video decoding device 1701 may be mounted as an individual circuit, or may be mounted as one integrated circuit.

The video decoding device 1701 decodes the input encoded stream and outputs the decoded video. The video decoding device 1701 can receive the encoded stream from the video encoding device 701 in FIG. 7 via the communication network.

The arithmetic decoding unit 1711 decodes the encoded stream by the CABAC decoding method, outputs the quantization coefficient of the decoding target block in the decoding target image to the inverse quantization unit 1712, and motion compensates the motion vector for the decoding target block. To the unit 1717.

The inverse quantization unit 1712 performs inverse quantization on the quantization coefficient output from the arithmetic decoding unit 1711 to generate an inverse quantization coefficient, and outputs the generated inverse quantization coefficient to the inverse orthogonal transform unit 1713. . The inverse orthogonal transform unit 1713 performs inverse orthogonal transform on the inverse quantization coefficient to generate a prediction error, and outputs the generated prediction error to the reconstruction unit 1714.

The motion compensation unit 1717 performs motion compensation processing on the decoding target block using the motion vector output from the arithmetic decoding unit 1711 and the reference image output from the memory 1719, generates an inter-prediction predicted image, and selects it. To the unit 1718. The selection unit 1718 selects a prediction image output by either the intra-frame prediction unit 1716 or the motion compensation unit 1717 and outputs the prediction image to the reconstruction unit 1714.

The reconstruction unit 1714 adds the prediction image output from the selection unit 1718 and the prediction error output from the inverse orthogonal transform unit 1713 to generate a reconstruction image, and the generated reconstruction image is converted into an in-loop filter 1715 and It outputs to the intra-frame prediction part 1716.

The intra-frame prediction unit 1716 performs intra prediction on the decoding target block using the reconstructed image of the decoded block output from the reconstruction unit 1714, and outputs a prediction image of intra prediction to the selection unit 1718.

The in-loop filter 1715 performs a filtering process such as a deblocking filter and a sample adaptive offset filter on the reconstructed image output from the reconstructing unit 1714 to generate a decoded image. Then, the in-loop filter 1715 outputs the decoded image for one frame as the decoded video and also outputs it to the memory 1719.

The memory 1719 stores the decoded image output from the in-loop filter 1715. The decoded image stored in the memory 1719 is output to the motion compensation unit 1717 as a reference image for the subsequent image.

FIG. 18 shows a first functional configuration example of the arithmetic decoding unit 1711 in FIG. The arithmetic decoding unit 1711 in FIG. 18 includes a decoding unit 1801, a determination unit 1802, and a generation unit 1803. The determination unit 1802 includes a difference motion vector candidate calculation unit 1811 and an estimated difference motion vector calculation unit 1812. The decoding unit 1801, the determination unit 1802, and the generation unit 1803 correspond to the first decoding unit 311, the determination unit 312 and the generation unit 313 in FIG.

The decoding unit 1801 decodes the encoded stream using a variable occurrence probability by CABAC context modeling, and restores the quantization coefficient of the decoding target block. Further, the decoding unit 1801 restores the absolute values of the x component and the y component of the differential motion vector and the code flags of the x component and the y component of the differential motion vector. Decoding section 1801 then outputs the absolute value of each component of the difference motion vector to determination section 1802 and outputs the sign flag of each component of the difference motion vector to generation section 1803.

The difference motion vector candidate calculation unit 1811 calculates a positive sign and a negative sign of the x component of the difference motion vector, a positive sign and a negative sign of the y component from the absolute values of the x component and the y component of the difference motion vector. Based on these four combinations, four differential motion vector candidates are calculated.

The estimated difference motion vector calculation unit 1812 obtains four reference block candidates corresponding to each of the difference motion vector candidates by using the prediction motion vector and the four difference motion vector candidates for the decoding target block. The predicted motion vector is obtained from the motion vectors already calculated for the blocks around the decoding target block.

Then, the estimated difference motion vector calculation unit 1812 uses the decoded pixel value of the decoded pixel adjacent to the decoding target block and the decoded pixel value of the decoded pixel included in each of the four reference block candidates, to estimate the difference. Calculate the motion vector.

The generation unit 1803 determines the code of each component of the differential motion vector from the code of each component of the estimated differential motion vector based on the code flag of each component of the differential motion vector, and generates a differential motion vector.

When mvd_sign_flag [0] = 0, the generation unit 1803 does not change the sign of the x component of the estimated difference motion vector. On the other hand, when mvd_sign_flag [0] = 1, the generation unit 1803 changes the sign of the x component of the estimated difference motion vector. For example, if the sign of the x component of the estimated difference motion vector is positive, the generation unit 1803 changes the sign to negative to generate the x component of the difference motion vector. If the sign of the x component of the estimated difference motion vector is negative, the generation unit 1803 generates the x component of the difference motion vector by changing the sign to positive.

When mvd_sign_flag [1] = 0, the generation unit 1803 does not change the sign of the y component of the estimated difference motion vector. On the other hand, when mvd_sign_flag [1] = 1, the generation unit 1803 changes the sign of the y component of the estimated difference motion vector. For example, if the sign of the y component of the estimated difference motion vector is positive, the generation unit 1803 generates the y component of the difference motion vector by changing the sign to negative. If the sign of the y component of the estimated difference motion vector is negative, the generation unit 1803 generates the y component of the difference motion vector by changing the sign to positive.

Next, the generation unit 1803 calculates a motion vector for the decoding target block by adding the predicted motion vector for the decoding target block and the generated differential motion vector.

FIG. 19 is a flowchart showing a specific example of video decoding processing performed by the video decoding device 1701 in FIG. First, the arithmetic decoding unit 1711 performs variable length decoding on the encoded stream, and generates the quantization coefficient and prediction mode information of the decoding target block (step 1901). Then, the arithmetic decoding unit 1711 checks whether the prediction mode information of the decoding target block indicates inter prediction or intra prediction (step 1902).

When the prediction mode information indicates inter prediction (step 1902, YES), the arithmetic decoding unit 1711 uses the absolute value and the sign flag of each component of the difference motion vector included in the prediction mode information to perform motion. A vector is generated (step 1903). Then, the motion compensation unit 1717 performs motion compensation processing on the decoding target block using the generated motion vector (step 1904).

On the other hand, when the prediction mode information indicates intra prediction (NO in step 1902), the intra-frame prediction unit 1716 performs intra prediction on the decoding target block (step 1907).

Next, the inverse quantization unit 1712 and the inverse orthogonal transform unit 1713 decode the quantization coefficient of the decoding target block and generate a prediction error (step 1905). Then, the selection unit 1718, the reconstruction unit 1714, and the in-loop filter 1715 generate a decoded image from the prediction error using the prediction image output by either the motion compensation unit 1717 or the intra-frame prediction unit 1716.

Next, the video decoding device 1701 determines whether or not the decoding of the encoded stream has been completed (step 1906). If an unprocessed code string remains (step 1906, NO), the video decoding device 1701 repeats the processing from step 1901 on for the next code string. Then, when decoding of the encoded stream is completed (step 1906, YES), the video decoding device 1701 ends the process.

FIG. 20 is a flowchart showing an example of the first motion vector generation process in step 1903 of FIG. In the first motion vector generation process, the estimated difference motion vector is calculated by the first calculation method shown in FIG.

First, the difference motion vector candidate calculation unit 1811 of the determination unit 1802 calculates four difference motion vector candidates based on the four combinations of the x and y component codes of the difference motion vector (step 2001).

Next, the estimated difference motion vector calculation unit 1812 obtains four reference block candidates indicated by each of the four difference motion vector candidates (step 2002).

Next, the estimated difference motion vector calculation unit 1812 calculates the statistical value B0 of the decoded pixel value of the decoded pixel adjacent to the decoding target block in the decoding target image (step 2003).

Next, the estimated difference motion vector calculation unit 1812 selects the decoded pixels in the reference block candidates adjacent to the decoded pixels used in step 2003 when each reference block candidate is arranged so as to overlap the position of the decoding target block. Specify (step 2004). Then, the estimated difference motion vector calculation unit 1812 calculates the statistical value Bi (i = 1 to 4) of the decoded pixel value of the identified decoded pixel.

Next, the estimated difference motion vector calculation unit 1812 obtains a reference block candidate having a statistical value closest to the statistical value B0 among the statistical values B1 to B4, and obtains a differential motion vector candidate indicating the obtained reference block candidate. The estimated difference motion vector is determined (step 2005).

Next, the generation unit 1803 generates a difference motion vector using the sign flag of each component of the difference motion vector and the estimated difference motion vector, and adds the predicted motion vector and the difference motion vector to thereby generate a motion vector. Is calculated (step 2006).

FIG. 21 is a flowchart showing an example of the second motion vector generation process in step 1903 of FIG. In the second motion vector generation process, the estimated difference motion vector is calculated by the second calculation method shown in FIG. The processing in step 2101, step 2102, and step 2105 in FIG. 21 is the same as the processing in step 2001, step 2002, and step 2006 in FIG. 20.

In step 2103, when the estimated difference motion vector calculation unit 1812 arranges each reference block candidate so as to overlap the position of the decoding target block, the estimated difference motion vector calculation unit 1812 includes a reference block candidate adjacent to the surrounding decoded pixels in the decoding target image. Identify decoded pixels. Then, for each reference block candidate, the estimated difference motion vector calculation unit 1812 calculates the absolute difference between the decoded pixel value of the surrounding decoded pixel in the decoding target image and the decoded pixel value of the decoded pixel in the reference block candidate. Calculate the sum.

Next, the estimated difference motion vector calculation unit 1812 obtains a reference block candidate having the smallest difference absolute value sum among the four reference block candidates, and obtains a difference motion vector candidate indicating the obtained reference block candidate as an estimated difference. A motion vector is determined (step 2104).

FIG. 22 is a flowchart showing an example of the third motion vector generation process in step 1903 of FIG. In the third motion vector generation process, the estimated difference motion vector is calculated by the third calculation method shown in FIG. The processing in step 2201, step 2202, and step 2205 in FIG. 22 is the same as the processing in step 2001, step 2002, and step 2006 in FIG.

In step 2203, the estimated difference motion vector calculation unit 1812 identifies two columns of decoded pixels in the decoding target image that are adjacent to the outside of the decoding target block boundary. Then, the estimated difference motion vector calculation unit 1812 calculates a predicted pixel value on the boundary of the decoding target block from the decoded pixel values of the decoded pixels in the two columns.

Next, the estimated difference motion vector calculation unit 1812 decodes two columns in the reference block candidate that are adjacent to the inner side of the boundary of the decoding target block when each reference block candidate is arranged at the position of the decoding target block. Identify the completed pixel. Then, the estimated difference motion vector calculation unit 1812 calculates a predicted pixel value on the boundary of the decoding target block from the decoded pixel values of the decoded pixels in the two columns.

Next, the estimated difference motion vector calculation unit 1812 calculates, for each reference block candidate, the predicted pixel value calculated from the decoded pixel in the decoding target image and the predicted pixel value calculated from the decoded pixel in the reference block candidate. Calculate the sum of absolute differences.

Next, the estimated difference motion vector calculation unit 1812 obtains a reference block candidate having the smallest difference absolute value sum among the four reference block candidates, and obtains a difference motion vector candidate indicating the obtained reference block candidate as an estimated difference. A motion vector is determined (step 2204).

Meanwhile, the video encoding device 101 in FIG. 1 and the video decoding device 301 in FIG. 3 generate a plurality of motion vector candidates by changing the code of the motion vector component instead of the code of the differential motion vector component. It is also possible to do.

In this case, the first encoding unit 111 in FIG. 1 encodes the encoding target block in the image included in the video.

The determining unit 112 generates a plurality of motion vector candidates including the first motion vector by changing a sign indicating whether the component of the first motion vector for the encoding target block is positive or negative. Then, the determination unit 112 determines the second motion vector from these motion vector candidates. At this time, the determination unit 112 performs local decoding pixel values of the encoded pixels included in each of the plurality of reference block candidates indicated by the plurality of motion vector candidates and the local decoding pixel value of the encoded pixel adjacent to the encoding target block. The second motion vector is determined using the value.

The generation unit 113 generates coincidence information indicating whether or not the code of the first motion vector component matches the code of the second motion vector component, and the second encoding unit 114 generates the first motion vector component. The absolute value and the coincidence information are encoded.

Further, the first decoding unit 311 in FIG. 3 decodes the encoded video, and restores the absolute value of the first motion vector component for the decoding target block in the image included in the encoded video. At this time, the first decoding unit 311 includes coincidence information indicating whether or not the code indicating whether the component of the first motion vector is positive or negative matches the code of the component of the second motion vector. Restored together with the absolute value of the first motion vector component.

The determining unit 312 generates a plurality of motion vector candidates by adding a sign to the absolute value of the component of the first motion vector, and determines the second motion vector from the motion vector candidates. At this time, the determination unit 312 uses the decoded pixel value of the pixel adjacent to the decoding target block and the decoded pixel value of the pixel included in each of the plurality of reference block candidates indicated by the plurality of motion vector candidates to perform the second motion. Determine the vector.

The generating unit 313 generates a first motion vector from the second motion vector based on the match information, and the second decoding unit 314 decodes the coefficient information of the decoding target block using the first motion vector.

7 uses the absolute value and the code flag of each component of the motion vector instead of the absolute value and the code flag of each component of the differential motion vector as the prediction mode information of the inter prediction. In this case, the arithmetic encoding unit 715 generates four motion vector candidates based on the four combinations of the codes of the respective components of the motion vector output from the inter-frame prediction unit 718.

FIG. 23 shows examples of motion vector candidates and reference block candidates. The reference image 2301 in FIG. 23 includes a block 2311 that exists at the same position as the encoding target block in the encoding target image. In the reference image 2301, the direction from left to right is the positive direction of the x coordinate, and the direction from top to bottom is the positive direction of the y coordinate.

In this case, motion vector candidates 2331 to 2334 are generated based on four combinations of the positive and negative signs of the x component of the motion vector and the positive and negative signs of the y component. The

The motion vector candidate 2331 is a vector from the block 2311 to the reference block candidate 2321, and the x component and the y component of the motion vector candidate 2331 are positive. The motion vector candidate 2332 is a vector from the block 2311 to the reference block candidate 2322, and the x component of the motion vector candidate 2332 is positive and the y component is negative.

The motion vector candidate 2333 is a vector from the block 2311 to the reference block candidate 2323, and the x component and the y component of the motion vector candidate 2333 are negative. The motion vector candidate 2334 is a vector from the block 2311 to the reference block candidate 2324, and the x component of the motion vector candidate 2334 is negative and the y component is positive.

FIG. 24 shows a second functional configuration example of the arithmetic encoding unit 715 of FIG. 24 includes a determination unit 2401, a generation unit 2402, and an encoding unit 2403. The determination unit 2401 includes a motion vector candidate calculation unit 2411 and an estimated motion vector calculation unit 2412. The determination unit 2401, the generation unit 2402, and the encoding unit 2403 correspond to the determination unit 112, the generation unit 113, and the second encoding unit 114 in FIG.

The motion vector candidate calculation unit 2411 calculates four motion vector candidates based on four combinations of the positive and negative signs of the x component of the motion vector and the positive and negative signs of the y component. calculate.

The estimated motion vector calculation unit 2412 obtains four reference block candidates corresponding to the four motion vector candidates. Then, the estimated motion vector calculation unit 2412 uses the locally decoded pixel value of the encoded pixel adjacent to the encoding target block and the locally decoded pixel value of the encoded pixel included in each of the four reference block candidates. To calculate an estimated motion vector.

The generating unit 2402 generates a code flag indicating whether or not the code of each component of the motion vector matches the code of each component of the estimated motion vector. The encoding unit 2403 encodes the absolute value and the sign flag of each component of the motion vector and the quantization coefficient output from the quantization unit 714 using CABAC context modeling using a variable occurrence probability.

mvd_sign_flag [0]
0: When the code of the x component of the motion vector is the same as the code of the x component of the estimated motion vector 1: When the code of the x component of the motion vector is different from the code of the x component of the estimated motion vector mvd_sign_flag [1]
0: The sign of the y component of the motion vector is the same as the sign of the y component of the estimated motion vector 1: The sign of the y component of the motion vector is different from the sign of the y component of the estimated motion vector

Thus, the code amount of the code flag is reduced by arithmetic coding using context modeling, similarly to the code flag of the differential motion vector.

FIG. 25 is a flowchart illustrating an example of a fourth code flag generation process performed by the arithmetic encoding unit 715 of FIG. 24 in Step 1304 of FIG. In the fourth code flag generation process, the estimated motion vector is calculated by the first calculation method shown in FIG. The processing in step 2503 and step 2504 in FIG. 25 is the same as the processing in step 1404 and step 1405 in FIG.

First, the motion vector candidate calculation unit 2411 of the determination unit 2401 calculates four motion vector candidates based on the four combinations of the x and y component codes of the motion vector (step 2501).

Next, the estimated motion vector calculation unit 2412 obtains four reference block candidates indicated by each of the four motion vector candidates (step 2502).

In step 2505, the estimated motion vector calculation unit 2412 obtains a reference block candidate having a statistical value closest to the statistical value A0 among the statistical values A1 to A4, and estimates a motion vector candidate indicating the obtained reference block candidate. The motion vector is determined.

Next, the generation unit 2402 compares the code of each component of the motion vector and the code of each component of the estimated motion vector, and determines the value of the code flag of each component (step 2506). If the code of the motion vector component and the code of the estimated motion vector component are the same, the value of the code flag of the component is determined to be “0”. If the two codes are different, the value of the code flag of the component Is determined to be “1”.

FIG. 26 is a flowchart illustrating an example of a fifth code flag generation process performed by the arithmetic encoding unit 715 in FIG. 24 in step 1304 in FIG. In the fifth code flag generation process, the estimated motion vector is calculated by the second calculation method shown in FIG. The processing in step 2601, step 2602, and step 2605 in FIG. 26 is the same as the processing in step 2501, step 2502, and step 2506 in FIG. 25, and the processing in step 2603 is the same as the processing in step 1504 in FIG. It is.

In step 2604, the estimated motion vector calculation unit 2412 obtains a reference block candidate having the smallest sum of absolute differences from the four reference block candidates, and obtains a motion vector candidate indicating the obtained reference block candidate as an estimated motion vector. To decide.

FIG. 27 is a flowchart illustrating an example of a sixth code flag generation process performed by the arithmetic encoding unit 715 of FIG. 24 in step 1304 of FIG. In the sixth code flag generation process, the estimated motion vector is calculated by the third calculation method shown in FIG. The processing of Step 2701, Step 2702, and Step 2705 of FIG. 27 is the same as the processing of Step 2501, Step 2502, and Step 2506 of FIG. 25, and the processing of Step 2703 is the same as the processing of Step 1604 of FIG. It is.

In step 2704, the estimated motion vector calculation unit 2412 obtains a reference block candidate having the smallest sum of absolute differences among the four reference block candidates, and obtains a motion vector candidate indicating the obtained reference block candidate as an estimated motion vector. To decide.

FIG. 28 shows a second functional configuration example of the arithmetic decoding unit 1711 in FIG. The arithmetic decoding unit 1711 in FIG. 28 includes a decoding unit 2801, a determination unit 2802, and a generation unit 2803. The determination unit 2802 includes a motion vector candidate calculation unit 2811 and an estimated motion vector calculation unit 2812. The decoding unit 2801, the determination unit 2802, and the generation unit 2803 respectively correspond to the first decoding unit 311, the determination unit 312, and the generation unit 313 in FIG.

The decoding unit 2801 decodes the encoded stream using a variable occurrence probability by CABAC context modeling, and restores the quantization coefficient of the decoding target block. Furthermore, the decoding unit 2801 restores the absolute values of the x and y components of the motion vector and the code flags of the x and y components of the motion vector. Then, decoding section 2801 outputs the absolute value of each component of the motion vector to determination section 2802, and outputs the sign flag of each component of the motion vector to generation section 2803.

The motion vector candidate calculation unit 2811 calculates the positive and negative signs of the x and y components of the motion vector and the positive and negative signs of the y component from the absolute values of the x and y components of the motion vector. Based on the combination, four motion vector candidates are calculated.

The estimated motion vector calculation unit 2812 obtains four reference block candidates corresponding to each of the four motion vector candidates. Then, the estimated motion vector calculation unit 2812 uses the decoded pixel value of the decoded pixel adjacent to the decoding target block and the decoded pixel value of the decoded pixel included in each of the four reference block candidates, to estimate the motion vector. Calculate

The generation unit 2803 determines the code of each component of the motion vector from the code of each component of the estimated motion vector based on the code flag of each component of the motion vector, and generates a motion vector for the decoding target block.

When mvd_sign_flag [0] = 0, the generation unit 2803 does not change the sign of the x component of the estimated motion vector. On the other hand, when mvd_sign_flag [0] = 1, the generation unit 2803 changes the sign of the x component of the estimated motion vector.

When mvd_sign_flag [1] = 0, the generation unit 2803 does not change the sign of the y component of the estimated motion vector. On the other hand, when mvd_sign_flag [1] = 1, the generation unit 2803 changes the sign of the y component of the estimated motion vector.

FIG. 29 is a flowchart illustrating an example of a fourth motion vector generation process performed by the arithmetic decoding unit 1711 in FIG. 28 in step 1903 in FIG. In the fourth motion vector generation process, the estimated motion vector is calculated by the first calculation method shown in FIG. The processing in step 2903 and step 2904 in FIG. 29 is the same as the processing in step 2003 and step 2004 in FIG.

First, the motion vector candidate calculation unit 2811 of the determination unit 2802 calculates four motion vector candidates based on the four combinations of the x and y component codes of the motion vector (step 2901).

Next, the estimated motion vector calculation unit 2812 obtains four reference block candidates indicated by each of the four motion vector candidates (step 2902).

In step 2905, the estimated motion vector calculation unit 2812 obtains a reference block candidate having a statistical value closest to the statistical value B0 among the statistical values B1 to B4, and estimates a motion vector candidate indicating the obtained reference block candidate. The motion vector is determined.

Next, the generation unit 2803 calculates a motion vector using the sign flag of each component of the motion vector and the estimated motion vector (step 2906).

FIG. 30 is a flowchart illustrating an example of a fifth motion vector generation process performed by the arithmetic decoding unit 1711 in FIG. 28 in Step 1903 in FIG. In the fifth motion vector generation process, the estimated motion vector is calculated by the second calculation method shown in FIG. The processing in step 3001, step 3002, and step 3005 in FIG. 30 is the same as the processing in step 2901, step 2902, and step 2906 in FIG. 29, and the processing in step 3003 is the same as the processing in step 2103 in FIG. It is.

In step 3004, the estimated motion vector calculation unit 2812 obtains a reference block candidate having the smallest sum of absolute differences among the four reference block candidates, and obtains a motion vector candidate indicating the obtained reference block candidate as an estimated motion vector. To decide.

FIG. 31 is a flowchart showing an example of sixth motion vector generation processing performed by the arithmetic decoding unit 1711 in FIG. 28 in step 1903 in FIG. In the sixth motion vector generation process, the estimated motion vector is calculated by the third calculation method shown in FIG. The processing in step 3101, step 3102, and step 3105 in FIG. 31 is the same as the processing in step 2901, step 2902, and step 2906 in FIG. 29, and the processing in step 3103 is the same as the processing in step 2203 in FIG. 22. It is.

In step 3104, the estimated motion vector calculation unit 2812 obtains a reference block candidate having the smallest sum of absolute differences from the four reference block candidates, and obtains a motion vector candidate indicating the obtained reference block candidate as an estimated motion vector. To decide.

FIG. 32 shows a functional configuration example of the video encoding system. 32 includes the video encoding device 701 in FIG. 7 and the video decoding device 1701 in FIG. 17 and is used for various purposes. For example, the video encoding system 3201 may be a video camera, a video transmission device, a video reception device, a videophone system, a computer, or a mobile phone.

1 and FIG. 7 is merely an example, and some components may be omitted or changed depending on the use or conditions of the video encoding device. The configuration of the arithmetic encoding unit 715 in FIGS. 8 and 24 is merely an example, and some components may be omitted or changed according to the use or conditions of the video encoding device. The video encoding apparatus may adopt an encoding method other than HEVC, or may adopt a variable length encoding method other than CABAC.

3 and 17 are merely examples, and some components may be omitted or changed according to the use or conditions of the video decoding device. The configuration of the arithmetic decoding unit 1711 in FIGS. 18 and 28 is merely an example, and some components may be omitted or changed according to the use or conditions of the video decoding device. The video decoding apparatus may employ a decoding scheme other than HEVC or a variable length decoding scheme other than CABAC.

The configuration of the video encoding system 3201 in FIG. 32 is merely an example, and some components may be omitted or changed according to the use or conditions of the video encoding system 3201.

The flowcharts shown in FIGS. 2, 4, 13 to 16, 19 to 22, 25 to 27, and 29 to 31 are merely examples, and the configuration of the video encoding device or the video decoding device is shown. Alternatively, some processes may be omitted or changed according to conditions.

For example, in step 1504 in FIG. 15, step 1604 in FIG. 16, step 2103 in FIG. 21, and step 2203 in FIG. 22, another index (difference squared) indicating the degree of difference or similarity is used instead of the difference absolute value sum. Sum etc.) may be used. Similarly, in Step 2603 of FIG. 26, Step 2703 of FIG. 27, Step 3003 of FIG. 30, and Step 3103 of FIG. 31, another index indicating the degree of difference or similarity is used instead of the sum of absolute differences. Also good.

The motion vector, the predicted motion vector, the difference motion vector, the difference motion vector candidate, and the motion vector candidate shown in FIG. 5, FIG. 6, and FIG. 23 are merely examples, and these vectors change according to the encoding target video. To do.

The calculation methods shown in FIGS. 9 to 12 are merely examples, and the estimated difference motion vector or the estimated motion vector may be calculated by another calculation method using the local decoded pixel value or the decoded pixel value.

The video encoding device 101 in FIG. 1, the video decoding device 301 in FIG. 3, the video encoding device 701 in FIG. 7, and the video decoding device 1701 in FIG. 17 can also be implemented as hardware circuits, as shown in FIG. It can also be implemented using such an information processing apparatus (computer).

33 includes a central processing unit (CPU) 3301, a memory 3302, an input device 3303, an output device 3304, an auxiliary storage device 3305, a medium driving device 3306, and a network connection device 3307. These components are connected to each other by a bus 3308.

The memory 3302 is a semiconductor memory such as a Read Only Memory (ROM), a Random Access Memory (RAM), or a flash memory, and stores programs and data used for processing. The memory 3302 can be used as the memory 724 in FIG. 7 and the memory 1719 in FIG.

The CPU 3301 (processor) operates as, for example, the first encoding unit 111, the determination unit 112, the generation unit 113, and the second encoding unit 114 in FIG. 1 by executing a program using the memory 3302.

The CPU 3301 also operates as the first decoding unit 311, the determination unit 312, the generation unit 313, and the second decoding unit 314 in FIG. 3 by executing the program using the memory 3302.

The CPU 3301 uses the memory 3302 to execute a program, thereby performing block division unit 711, prediction error generation unit 712, orthogonal transform unit 713, quantization unit 714, arithmetic coding unit 715, and coding control in FIG. The unit 716 also operates. The CPU 3301 uses the memory 3302 to execute a program, so that an intra-frame prediction unit 717, an inter-frame prediction unit 718, a selection unit 719, an inverse quantization unit 720, an inverse orthogonal transform unit 721, a reconstruction unit 722, and It also operates as an in-loop filter 723.

The CPU 3301 also operates as the determination unit 801, the generation unit 802, and the encoding unit 803 in FIG. 8 by executing the program using the memory 3302. The CPU 3301 also operates as a difference motion vector calculation unit 811, a difference motion vector candidate calculation unit 812, and an estimated difference motion vector calculation unit 813 by executing a program using the memory 3302.

The CPU 3301 also operates as the arithmetic decoding unit 1711, the inverse quantization unit 1712, the inverse orthogonal transform unit 1713, the reconstruction unit 1714, and the in-loop filter 1715 in FIG. 17 by executing the program using the memory 3302. . The CPU 3301 also operates as an intra-frame prediction unit 1716, a motion compensation unit 1717, and a selection unit 1718 by executing a program using the memory 3302.

The CPU 3301 also operates as the decoding unit 1801, the determination unit 1802, the generation unit 1803, the difference motion vector candidate calculation unit 1811, and the estimated difference motion vector calculation unit 1812 in FIG. 18 by executing the program using the memory 3302. To do.

The CPU 3301 also operates as the determination unit 2401, the generation unit 2402, the encoding unit 2403, the motion vector candidate calculation unit 2411, and the estimated motion vector calculation unit 2412 in FIG. 24 by executing a program using the memory 3302. .

The CPU 3301 also operates as the decoding unit 2801, the determination unit 2802, the generation unit 2803, the motion vector candidate calculation unit 2811, and the estimated motion vector calculation unit 2812 in FIG. 28 by executing the program using the memory 3302.

The input device 3303 is, for example, a keyboard, a pointing device, or the like, and is used for inputting an instruction or information from a user or an operator. The output device 3304 is, for example, a display device, a printer, a speaker, or the like, and is used to output an inquiry to a user or an operator or a processing result. The processing result may be a decoded video.

The auxiliary storage device 3305 is, for example, a magnetic disk device, an optical disk device, a magneto-optical disk device, a tape device, or the like. The auxiliary storage device 3305 may be a hard disk drive. The information processing apparatus can store programs and data in the auxiliary storage device 3305 and load them into the memory 3302 for use.

The medium driving device 3306 drives the portable recording medium 3309 and accesses the recorded contents. The portable recording medium 3309 is a memory device, a flexible disk, an optical disk, a magneto-optical disk, or the like. The portable recording medium 3309 may be a Compact Disk Read Only Memory (CD-ROM), Digital Versatile Disk (DVD), or Universal Serial Bus (USB) memory. A user or an operator can store programs and data in the portable recording medium 3309 and load them into the memory 3302 for use.

As described above, the computer-readable recording medium for storing the program and data used for processing includes physical (non-transitory) media such as the memory 3302, the auxiliary storage device 3305, and the portable recording medium 3309. A recording medium is included.

The network connection device 3307 is a communication interface circuit that is connected to a communication network such as Local Area Network (LAN) or the Internet and performs data conversion accompanying communication. The network connection device 3307 can transmit the encoded stream to the video decoding device and receive the encoded stream from the video encoding device. The information processing apparatus can receive a program and data from an external apparatus via the network connection apparatus 3307 and can use them by loading them into the memory 3302.

Note that the information processing apparatus does not have to include all the components shown in FIG. 33, and some of the components can be omitted depending on the application or conditions. For example, when an interface with a user or an operator is unnecessary, the input device 3303 and the output device 3304 may be omitted. When the information processing apparatus does not access the portable recording medium 3309, the medium driving device 3306 may be omitted.

Although the disclosed embodiments and their advantages have been described in detail, those skilled in the art can make various modifications, additions and omissions without departing from the scope of the present invention as explicitly set forth in the claims. Let's go.

Claims

A first encoding unit that encodes an encoding target block in an image included in the video;
A code indicating whether a first differential motion vector component is positive or negative by generating a first differential motion vector from a motion vector for the encoding target block and a predicted motion vector for the encoding target block To generate a plurality of differential motion vector candidates including the first differential motion vector, and locally decoded pixel values of encoded pixels adjacent to the encoding target block, and the plurality of differential motion vector candidates A determination unit that determines a second differential motion vector from among the plurality of differential motion vector candidates using a locally decoded pixel value of an encoded pixel included in each of the plurality of reference block candidates indicated by:
A generating unit that generates coincidence information indicating whether a code of the component of the first differential motion vector matches a code of the component of the second differential motion vector;
A second encoding unit that encodes the absolute value of the component of the first differential motion vector and the match information;
A video encoding device comprising:
The first differential motion vector includes a first component that is a horizontal component in the image and a second component that is a vertical component in the image;
The determination unit generates four differential motion vector candidates based on four combinations of the positive sign and negative sign of the first component and the positive sign and negative sign of the second component And
The coincidence information includes a first flag indicating whether a sign of the first component of the first difference motion vector matches a sign of the first component of the second difference motion vector, and the first difference motion vector. 2. The video encoding apparatus according to claim 1, further comprising: a second flag indicating whether a code of the second component matches a code of the second component of the second differential motion vector.
3. The video encoding apparatus according to claim 1, wherein the second encoding unit encodes the match information using a variable occurrence probability in context adaptive binary arithmetic encoding.
The determination unit calculates a first statistical value of a local decoded pixel value of an encoded pixel adjacent to the encoding target block, and a local decoded pixel value of an encoded pixel included in each of the plurality of reference block candidates The second statistical motion vector is calculated, and the second differential motion vector is determined by comparing the first statistical value and the second statistical value of each of the plurality of reference block candidates. Item 4. The video encoding device according to any one of Items 1 to 3.
The determination unit includes an absolute difference value between a local decoded pixel value of an encoded pixel adjacent to the encoding target block and a local decoded pixel value of an encoded pixel included in each of the plurality of reference block candidates. 4. The second differential motion vector is determined by calculating a sum and comparing the difference absolute value sum of each of the plurality of reference block candidates. 5. Video encoding device.
The determination unit calculates a first predicted pixel value on a boundary of the encoding target block from a locally decoded pixel value of an encoded pixel adjacent to the encoding target block, and includes the first reference pixel value in each of the plurality of reference block candidates Calculating a second predicted pixel value on the boundary from a locally decoded pixel value of the encoded pixel to be calculated, calculating a sum of absolute differences between the first predicted pixel value and the second predicted pixel value, 4. The video encoding device according to claim 1, wherein the second differential motion vector is determined by comparing the difference absolute value sums of a plurality of reference block candidates. 5.
A first encoding unit that encodes an encoding target block in an image included in the video;
A plurality of motion vector candidates including the first motion vector are generated by changing a sign indicating whether a component of the first motion vector for the encoding target block is positive or negative, and the encoding target The plurality of motions using the locally decoded pixel values of the encoded pixels adjacent to the block and the locally decoded pixel values of the encoded pixels included in each of the plurality of reference block candidates indicated by the plurality of motion vector candidates. A determination unit for determining a second motion vector from among vector candidates;
A generating unit that generates coincidence information indicating whether a sign of the component of the first motion vector matches a sign of the component of the second motion vector;
A video encoding apparatus comprising: a second encoding unit that encodes the absolute value of the component of the first motion vector and the coincidence information.
Video encoding device
Encode the encoding target block in the image included in the video,
Generating a first differential motion vector from a motion vector for the encoding target block and a predicted motion vector for the encoding target block;
Generating a plurality of differential motion vector candidates including the first differential motion vector by changing a sign indicating whether a component of the first differential motion vector is positive or negative;
Using the local decoded pixel value of the encoded pixel adjacent to the encoding target block and the local decoded pixel value of the encoded pixel included in each of the plurality of reference block candidates indicated by the plurality of differential motion vector candidates , Determining a second differential motion vector from the plurality of differential motion vector candidates,
Generating coincidence information indicating whether or not the code of the component of the first differential motion vector matches the code of the component of the second differential motion vector;
Encoding the absolute value of the component of the first differential motion vector and the match information;
And a video encoding method.
Encode the encoding target block in the image included in the video,
Generating a first differential motion vector from a motion vector for the encoding target block and a predicted motion vector for the encoding target block;
Generating a plurality of differential motion vector candidates including the first differential motion vector by changing a sign indicating whether a component of the first differential motion vector is positive or negative;
Using the local decoded pixel value of the encoded pixel adjacent to the encoding target block and the local decoded pixel value of the encoded pixel included in each of the plurality of reference block candidates indicated by the plurality of differential motion vector candidates , Determining a second differential motion vector from the plurality of differential motion vector candidates,
Generating coincidence information indicating whether or not the code of the component of the first differential motion vector matches the code of the component of the second differential motion vector;
Encoding the absolute value of the component of the first differential motion vector and the match information;
A video encoding program for causing a computer to execute processing.
The encoded video is decoded to restore the absolute value of the first differential motion vector component for the decoding target block in the image included in the encoded video, and the first differential motion vector component is positive or negative. A first decoding unit that restores coincidence information indicating whether or not the code indicating which of the two matches the code of the component of the second differential motion vector;
A plurality of differential motion vector candidates are generated by adding a sign to the absolute value of the component of the first differential motion vector, and the decoded pixel value of a pixel adjacent to the decoding target block and the plurality of differential motion vector candidates are A determination unit that determines the second differential motion vector from the plurality of differential motion vector candidates using a decoded pixel value of a pixel included in each of the plurality of reference block candidates shown;
Based on the coincidence information, the first differential motion vector is generated from the second differential motion vector, and the motion vector for the decoding target block is determined from the first differential motion vector and the predicted motion vector for the decoding target block. A generating unit to generate;
A second decoding unit that decodes coefficient information of the decoding target block using a motion vector for the decoding target block;
A video decoding device comprising:
The first differential motion vector includes a first component that is a horizontal component in the image and a second component that is a vertical component in the image;
The determination unit generates four differential motion vector candidates based on four combinations of the positive sign and negative sign of the first component and the positive sign and negative sign of the second component And
The coincidence information includes a first flag indicating whether a sign of the first component of the first difference motion vector matches a sign of the first component of the second difference motion vector, and the first difference motion vector. The video decoding apparatus according to claim 10, further comprising: a second flag indicating whether a code of the second component matches a code of the second component of the second differential motion vector.
The video decoding device according to claim 10 or 11, wherein the first decoding unit restores the matching information using a variable occurrence probability in context adaptive binary arithmetic coding.
The determining unit calculates a first statistical value of a decoded pixel value of a pixel adjacent to the decoding target block, calculates a second statistical value of a decoded pixel value of a pixel included in each of the plurality of reference block candidates, 13. The second differential motion vector is determined by comparing the first statistical value and the second statistical value of each of the plurality of reference block candidates. The video decoding device according to 1.
The determination unit calculates a sum of absolute differences between a decoded pixel value of a pixel adjacent to the decoding target block and a decoded pixel value of a pixel included in each of the plurality of reference block candidates, and the plurality of references 13. The video decoding device according to claim 10, wherein the second differential motion vector is determined by comparing the difference absolute value sums of the respective block candidates.
The determination unit calculates a first prediction pixel value on a boundary of the decoding target block from a decoding pixel value of a pixel adjacent to the decoding target block, and decodes a pixel value of a pixel included in each of the plurality of reference block candidates A second predicted pixel value on the boundary is calculated, a difference absolute value sum between the first predicted pixel value and the second predicted pixel value is calculated, and the difference absolute value of each of the plurality of reference block candidates is calculated. The video decoding apparatus according to claim 10, wherein the second differential motion vector is determined by comparing value sums.
The encoded video is decoded to restore the absolute value of the first motion vector component for the decoding target block in the image included in the encoded video, and the first motion vector component is either positive or negative A first decoding unit for restoring matching information indicating whether or not a code indicating whether or not a code matches a code of a component of the second motion vector;
A plurality of motion vector candidates are generated by adding a sign to the absolute value of the component of the first motion vector, and a decoded pixel value of a pixel adjacent to the block to be decoded and a plurality of motion vector candidates indicated by the plurality of motion vector candidates A determination unit configured to determine the second motion vector from the plurality of motion vector candidates using a decoded pixel value of a pixel included in each of the reference block candidates;
A generating unit that generates the first motion vector from the second motion vector based on the match information;
A second decoding unit for decoding coefficient information of the decoding target block using the first motion vector;
A video decoding device comprising:
Video decoding device
The encoded video is decoded to restore the absolute value of the first differential motion vector component for the decoding target block in the image included in the encoded video, and the first differential motion vector component is positive or negative. Reconstructing the coincidence information indicating whether the code indicating which is the same as the code of the component of the second differential motion vector;
Generating a plurality of differential motion vector candidates by adding a sign to the absolute value of the component of the first differential motion vector;
Using the decoded pixel value of a pixel adjacent to the decoding target block and the decoded pixel value of a pixel included in each of a plurality of reference block candidates indicated by the plurality of difference motion vector candidates, the plurality of difference motion vector candidates Determining the second differential motion vector from within,
Generating the first differential motion vector from the second differential motion vector based on the match information;
Generating a motion vector for the decoding target block from the first differential motion vector and a predicted motion vector for the decoding target block;
Decoding coefficient information of the decoding target block using a motion vector for the decoding target block;
And a video decoding method.
The encoded video is decoded to restore the absolute value of the first differential motion vector component for the decoding target block in the image included in the encoded video, and the first differential motion vector component is positive or negative. Reconstructing the coincidence information indicating whether the code indicating which is the same as the code of the component of the second differential motion vector;
Generating a plurality of differential motion vector candidates by adding a sign to the absolute value of the component of the first differential motion vector;
Using the decoded pixel value of a pixel adjacent to the decoding target block and the decoded pixel value of a pixel included in each of a plurality of reference block candidates indicated by the plurality of difference motion vector candidates, the plurality of difference motion vector candidates Determining the second differential motion vector from within,
Generating the first differential motion vector from the second differential motion vector based on the match information;
Generating a motion vector for the decoding target block from the first differential motion vector and a predicted motion vector for the decoding target block;
Decoding coefficient information of the decoding target block using a motion vector for the decoding target block;
A video decoding program for causing a computer to execute processing.
A first encoding unit that encodes an encoding target block in an image included in the video;
A first differential motion vector is generated from the first motion vector for the encoding target block and the first predicted motion vector for the encoding target block, and the component of the first differential motion vector is either positive or negative A plurality of first differential motion vector candidates including the first differential motion vector by generating a code indicating whether or not, and a local decoded pixel value of an encoded pixel adjacent to the encoding target block; and A second difference is selected from among the plurality of first difference motion vector candidates using local decoded pixel values of encoded pixels included in each of the plurality of first reference block candidates indicated by the plurality of first difference motion vector candidates. A first determination unit for determining a motion vector;
A second generation unit that generates first matching information indicating whether or not a code of the component of the first differential motion vector matches a code of the component of the second differential motion vector;
A second encoding unit that encodes the absolute value of the component of the first differential motion vector and the first match information;
The encoded video is decoded, the absolute value of the third differential motion vector component for the decoding target block in the image included in the encoded video is restored, and the sign of the third differential motion vector component is fourth. A first decoding unit that restores second matching information indicating whether or not the code of the component of the difference motion vector matches,
A plurality of second difference motion vector candidates are generated by adding a sign to the absolute value of the component of the third difference motion vector, the decoded pixel value of a pixel adjacent to the decoding target block, and the plurality of second differences A second determination for determining the fourth differential motion vector from the plurality of second differential motion vector candidates using a decoded pixel value of a pixel included in each of the plurality of second reference block candidates indicated by the motion vector candidate And
Based on the second match information, the third differential motion vector is generated from the fourth differential motion vector, and the decoding target block is calculated from the third differential motion vector and the second predicted motion vector for the decoding target block. A second generator for generating a second motion vector for
A second decoding unit that decodes coefficient information of the decoding target block using the second motion vector;
A video encoding system comprising:
A first encoding unit that encodes an encoding target block in an image included in the video;
A plurality of first motion vector candidates including the first motion vector are generated by changing a sign indicating whether a component of the first motion vector for the encoding target block is positive or negative, and the code The local decoded pixel value of the encoded pixel adjacent to the encoding target block and the local decoded pixel value of the encoded pixel included in each of the plurality of first reference block candidates indicated by the plurality of first motion vector candidates are used. A first determination unit for determining a second motion vector from among the plurality of first motion vector candidates;
A second generator for generating first match information indicating whether or not the sign of the component of the first motion vector matches the sign of the component of the second motion vector;
A second encoding unit for encoding the absolute value of the component of the first motion vector and the first match information;
The encoded video is decoded to restore the absolute value of the third motion vector component for the block to be decoded in the image included in the encoded video, and the sign of the third motion vector component is the fourth motion vector. A first decoding unit that restores second matching information indicating whether or not the code of the component matches,
A plurality of second motion vector candidates are generated by adding a sign to the absolute value of the component of the third motion vector, the decoded pixel values of pixels adjacent to the decoding target block, and the plurality of second motion vector candidates A second determination unit that determines the fourth motion vector from among the plurality of second motion vector candidates using a decoded pixel value of a pixel included in each of the plurality of second reference block candidates indicated by:
A second generator for generating the third motion vector from the fourth motion vector based on the second match information;
A second decoding unit that decodes coefficient information of the decoding target block using the third motion vector;
A video encoding system comprising: