JP2017092651A - Video coding device, video decoding device, video coding method, video decoding method, video coding program, and video decoding program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress reduction of accuracy of a prediction image while suppressing deterioration of coding efficiency.SOLUTION: A video coding device coding a video per block unit by using an intra-prediction and an inter-prediction, comprises: prediction motion vector conducting means of conducting a prediction motion vector candidate from a candidate block surrounding a target block; and prediction motion vector setting means of, when an intra-prediction mode is selected in the target block, setting the prediction motion vector conducted by the prediction motion vector guiding means as motion vector of the target block.SELECTED DRAWING: Figure 1

Description

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

  H.264 is a standard for video coding. H.264 / AVC and H.264 A video encoding method called H.265 / HEVC has been formulated. Hereinafter, HEVC (Non-Patent Document 1, hereinafter referred to as “prior art”) will be described as an example. In HEVC, an encoding target picture is divided into blocks called LCUs (Largest Coding Units), and encoding is performed for each LCU. The LCU can be further divided into a maximum of 3 times by a quadtree, from a maximum of 64 pixels × 64 pixels (hereinafter, n pixels × n pixels are abbreviated as nxn (n is 8, 16, 32, 64)) to 8 × 8. It is composed of blocks called CU (Coding Unit).

  Different prediction modes can be encoded for each CU. In HEVC, an intra prediction mode for predicting from adjacent encoded pixels of an encoding target block and an inter prediction mode for predicting from an encoded frame are defined. In the inter prediction mode, two types of motion information encoding modes are employed, that is, adaptive motion vector predictive encoding that transmits a differential motion vector and merge encoding that does not transmit a differential motion vector. Hereinafter, the two encoding modes will be described.

(Adaptive motion vector predictive coding)
In adaptive motion vector predictive coding, a reference image list for specifying a prediction direction, a reference image index for specifying a reference frame, two prediction motion vectors derived from a block around an encoding target block or an encoded block of an encoded frame A prediction motion vector index that identifies a prediction motion vector candidate to be used from the candidate list and a difference motion vector that is a difference from the prediction motion vector are encoded for each reference image list (L0 / L1).

  The motion vector predictor candidate list is derived in the priority order of the spatial motion vector predictor candidate adjacent to the encoding target block shown in FIG. 19 and the temporal motion vector candidate candidate and the zero motion vector predictor candidate of the encoded frame shown in FIG. The One spatial prediction motion vector candidate is derived from each of the block group A (A0, A1) and the block group B (B0, B1, B2), and scanned with the priority order of A0⇒A1, B0⇒B1⇒B2. . Further, it is determined whether or not the candidate block is in the inter prediction mode, and is derived only in the case of the inter prediction mode. Further, a candidate having the same reference image as the reference image of the block to be encoded is prioritized, and when the reference images are different, scaling is performed by the distance between the reference images. However, the candidates that require scaling are limited to the first one added to the motion vector predictor candidate list.

  Further, when the same motion vector is derived in each block group, only candidates with high priority are added, and candidates with low priority are not added. If the total number of spatial prediction motion vector candidates is less than 2, temporal prediction motion vector candidates are derived. The temporal prediction motion vector candidate is derived from the encoded frame (ColPic) specified by the slice header, and scanned with the priority order of H⇒C3. Here, similarly, only when the candidate block is in the inter prediction mode, the motion vector is scaled according to the distance between the reference images. If the total number of spatially predicted motion vector candidates and temporally predicted motion vector candidates is less than 2, it is added until zero predicted motion vectors (vectors having zero horizontal component and zero vertical component) are satisfied.

(Merge encoding)
In merge encoding, only the index of a candidate to be used is encoded from a maximum of five merge candidate lists derived from the encoded block around the encoding target block or the encoded frame. The merge candidate list is derived in the priority order of the spatial merge candidate, temporal merge candidate, combined bi-prediction candidate, and zero merge candidate. The candidate blocks of the spatial merge candidate and the temporal merge candidate are the same as those in FIGS. Spatial merge candidates are scanned with priorities of A1⇒B1⇒B0⇒A0⇒B2, and are derived only when the candidate block is in the inter prediction mode. However, in order to make it difficult to add duplicates to the merge candidate list, only candidates with high priority are added in the following cases, and candidates with low priority are not added.
-B1 motion information = A1 motion information-B0 motion information = B1 motion information-A0 motion information = A1 motion information-B2 motion information = A1 or B1 motion information

  The temporal merge candidate is the same as the adaptive motion vector predictive coding, and the reference image index is 0. Up to two combined bi-prediction candidates are derived for each of the L0 / L1 motion information with different merge index combinations. When the sum of the spatial merge candidate, the prediction merge candidate, and the combined bi-prediction candidate is less than 5, zero merge candidates (vectors in which the bi-directional reference image index is 0, the horizontal component, and the vertical component are 0) satisfy 5 Will be added.

Impress Japan Co., Ltd., “Impress Standard Textbook Series H.265 / HEVC Textbook,” 2013

  In the prior art, both of the two types of motion information encoding modes are not in the inter prediction mode when the motion vector predictor candidate list is derived from the candidate block adjacent to the encoding target block or the candidate block of the encoded frame. In this case, a predicted motion vector cannot be derived. In particular, when all candidate blocks are encoded in the intra prediction mode, zero motion vectors or zero merge candidates are added to the prediction motion vector candidate list or merge candidate list. In that case, the coding efficiency deteriorates because the code amount of the difference motion vector cannot be reduced in the adaptive motion vector predictive coding, and the prediction image becomes only the zero merge candidate in the merge coding, and the accuracy of the prediction image is lowered. There is a problem of doing.

  For example, as shown in FIG. 21, when an occlusion due to another object occurs in the middle of a moving object, another object is likely to be in the intra prediction mode. Further, in the case of a flat region or a simple pattern, there is a high possibility that the intra prediction mode is set even in the same continuous object.

  The present invention has been made in view of such circumstances, and a video encoding device, a video decoding device, and a video encoding that can prevent deterioration in accuracy of a predicted image while suppressing deterioration in encoding efficiency. It is an object to provide a method, a video decoding method, a video encoding program, and a video decoding program.

  One aspect of the present invention is a video encoding apparatus that encodes video in units of blocks using intra prediction and inter prediction, and derives a motion vector predictor that derives motion vector predictor candidates from candidate blocks around the target block. And a prediction motion vector setting means for setting, as the motion vector of the target block, a prediction motion vector derived by the prediction motion vector deriving means when an intra prediction mode is selected in the target block. Device.

  One aspect of the present invention is the video encoding device, wherein the predicted motion vector deriving unit determines the motion vector set by the predicted motion vector setting unit when the candidate block is in the intra prediction mode. The video encoding apparatus refers to a motion vector predictor candidate of the target block.

  One aspect of the present invention is the video encoding device, wherein the prediction motion vector deriving unit performs inter prediction mode in a predetermined order around the target block or from the encoded blocks of the encoded frame. A motion vector candidate is derived from a candidate block that is in the inter prediction mode, and if the number of motion vector predictor candidates is less than a predetermined value, a motion vector predictor candidate from the candidate block that is not in the inter prediction mode Is derived.

  One aspect of the present invention is the video encoding device, wherein the motion vector predictor setting unit satisfies a motion vector predictor candidate that satisfies a predetermined condition based on a motion vector statistic among the motion vector predictor candidates derived. Set.

  One aspect of the present invention is the video encoding device, wherein the condition is that a sum of absolute values of each element of the motion vector is maximum.

  One aspect of the present invention is the video encoding device, wherein the condition is a mode motion vector around the target block or in an encoded block of an encoded frame.

  One aspect of the present invention is a video decoding device that decodes encoded data obtained by encoding a video in units of blocks using intra prediction and inter prediction, and predicting motion vector candidates from candidate blocks around the target block. A prediction motion vector deriving unit for deriving and a prediction motion vector setting unit for setting the prediction motion vector derived by the prediction motion vector deriving unit as a motion vector of the target block when an intra prediction mode is selected in the target block A video decoding device.

  One aspect of the present invention is the video decoding device, in which the motion vector predictor deriving unit calculates the motion vector set by the motion vector predictor setting unit when the candidate block is in the intra prediction mode. It is a video decoding apparatus referred to as a prediction motion vector candidate of a target block.

  One aspect of the present invention is the video decoding device, wherein the prediction motion vector deriving unit is in the inter prediction mode in a predetermined order around the target block or the encoded block of the encoded frame. And predicting motion vector candidates from the candidate block in the inter prediction mode, and if the number of motion vector predictor candidates is less than a predetermined value, predicting motion vector candidates from the candidate block not in the inter prediction mode Is derived.

  One aspect of the present invention is the video decoding device, wherein the motion vector predictor setting unit selects a motion vector predictor candidate that satisfies a predetermined condition based on a motion vector statistic from the predicted motion vector candidates. Set.

  One aspect of the present invention is the video decoding device, wherein the condition is that a sum of absolute values of elements of a motion vector is maximum.

  One aspect of the present invention is the video decoding device, wherein the condition is a mode motion vector around the target block or in an encoded block of an encoded frame.

  One aspect of the present invention is a video encoding method performed by a video encoding apparatus that encodes video in units of blocks using intra prediction and inter prediction, and predicting motion vector candidates from candidate blocks around a target block. A prediction motion vector deriving step to be derived and a prediction motion vector setting step of setting the prediction motion vector derived by the prediction motion vector deriving step as a motion vector of the target block when the intra prediction mode is selected in the target block And a video encoding method.

  One aspect of the present invention is the video encoding method, wherein in the prediction motion vector derivation step, the motion vector set in the prediction motion vector setting step is used when the candidate block is in the intra prediction mode. The video encoding method is referred to as a predicted motion vector candidate of the target block.

  One aspect of the present invention is a video decoding method performed by a video decoding apparatus that decodes encoded data in which a video is encoded in units of blocks using intra prediction and inter prediction, and includes a candidate block around a target block. When a prediction motion vector derivation step for deriving a prediction motion vector candidate and an intra prediction mode is selected in the target block, the prediction motion vector derived by the prediction motion vector derivation step is set as a motion vector of the target block. A predictive motion vector setting step.

  One aspect of the present invention is the video decoding method, wherein, in the prediction motion vector derivation step, the motion vector set in the prediction motion vector setting step is used when the candidate block is in the intra prediction mode. This is a video decoding method that is referred to as a predicted motion vector candidate of a target block.

  One aspect of the present invention is a video encoding program for causing a computer to function as the video encoding device.

  One aspect of the present invention is a video decoding program for causing a computer to function as the video decoding device.

  According to the present invention, it is possible to obtain an effect that the accuracy of a predicted image can be prevented from being lowered while suppressing deterioration in encoding efficiency.

It is a block diagram which shows the structure of the video coding apparatus in the 1st Embodiment of this invention. It is a block diagram which shows the structure of the video coding apparatus in a prior art. It is a block diagram which shows the structure of the video decoding apparatus in the 1st Embodiment of this invention. It is a block diagram which shows the structure of the inter motion information generation part 23 in the video coding apparatus of 1st Embodiment. It is a block diagram which shows the structure of the inter motion information generation part 51 in the video decoding apparatus of 1st Embodiment. It is a block diagram which shows the structure of the intra motion information generation part 24 in 1st Embodiment. It is a flowchart which shows the motion vector setting process operation in 1st Embodiment. 7 is a flowchart showing processing operations of predicted motion vector candidate list generation units 232, 511, and 241 shown in FIGS. 4, 5, and 6. It is a flowchart which shows operation | movement of the prediction motion vector candidate list production | generation part in a prior art. It is a block diagram which shows the structure of the video coding apparatus in the 2nd Embodiment of this invention. It is a block diagram which shows the structure of the video decoding apparatus in the 2nd Embodiment of this invention. It is a block diagram which shows the structure of the inter motion information generation part 23 in 2nd Embodiment. It is a block diagram which shows the structure of the inter motion information generation part 51 in 2nd Embodiment. It is a block diagram which shows the structure of the intra motion information production | generation parts 24 and 50 in 2nd Embodiment. It is a flowchart which shows the processing operation of the motion vector predictor candidate list production | generation part 231,512,241 shown in FIG.12, FIG13 and FIG.14. It is a flowchart which shows the processing operation of the motion vector predictor candidate list production | generation part 231,512,241 shown in FIG.12, FIG13 and FIG.14. It is a block diagram which shows the structure of the intra motion information production | generation parts 24 and 50 in 3rd Embodiment. It is a flowchart which shows the motion vector setting process operation in 3rd Embodiment. It is explanatory drawing which shows the spatial prediction motion vector candidate adjacent to an encoding object block. It is explanatory drawing which shows the temporal motion vector predictor candidate of an encoded frame. It is explanatory drawing which shows the condition where another object tends to be in intra prediction mode when the occlusion by another object occurs in the middle of a moving object.

  In the following, an embodiment in which the present invention is applied to a video encoding device and a video decoding device compliant with HEVC will be described as an example, but the embodiment described below may not necessarily be compliant with HEVC. . In order to simplify the explanation, the LCU and the CU size are described as being fixed (for example, 64 × 64), but the present invention can be applied by performing the same processing for each CU even when the blocks are divided.

<First Embodiment>
With reference to FIG. 1, a video encoding apparatus according to the first embodiment will be described. FIG. 1 is a block diagram showing a configuration of a video encoding apparatus according to the first embodiment. For reference, FIG. 2 shows a conventional video encoding apparatus. In FIG. 1 and FIG. 2, the same code | symbol is provided to the same component. The configuration shown in FIG. 1 is different from the prior art in that an intra motion information generation unit 24 is newly added. The encoding target picture of the input video to be encoded is input to the encoding apparatus for each CU block, and encoded data corresponding to this block is output. This is repeatedly executed for each block of the encoding target picture in the raster scan order, thereby encoding the encoding target picture.

  The subtractor 11 outputs the difference between the input image input to the video encoding device 1 and the predicted image output from the intra prediction unit 17 or the inter prediction unit 19 to the orthogonal transform / quantization unit 12. On the other hand, the orthogonal transform / quantization unit 12 performs orthogonal transform and quantization on the difference output from the subtracter 11 and outputs the result to the variable length coding unit 13 and the inverse quantization / inverse orthogonal transform unit 14.

  The variable length encoding unit 13 performs variable length encoding on the quantization coefficient output from the orthogonal transform / quantization unit 12 and outputs the encoded coefficient from the video encoding device 1 as encoded data. The inverse quantization / inverse orthogonal transform unit performs inverse quantization and inverse orthogonal transform on the quantization coefficient output from the orthogonal transform / quantization unit 12 and outputs the result to the adder 15.

  The adder 15 outputs the sum of the image output from the inverse quantization / inverse orthogonal transform unit 14 and the predicted image to the intra prediction unit 17 and the loop filter unit 16. The loop filter unit 16 applies a loop filter to the sum of the image output from the inverse quantization / inverse orthogonal transform unit 14 and the predicted image output from the intra prediction unit 17 or the inter prediction unit 19, and supplies the decoded picture memory 18. Output.

  The decoded picture memory 18 stores the output of the loop filter unit 16, is output to the inter prediction unit 19 and the motion vector detection unit 21, and is used as a reference image at the time of inter prediction and motion vector detection of the subsequent encoding target block. The intra prediction unit 17 uses the sum of the image output from the inverse quantization / inverse orthogonal transform unit 14 and the prediction image output from the intra prediction unit 17 or the inter prediction unit 19 as a reference image to perform intra prediction of the block to be encoded. Generate an image.

  The inter prediction unit 19 generates an inter prediction image of the encoding target block using the reference image of the decoded picture memory. The intra / inter switch 20 switches the intra prediction unit 17 or the inter prediction unit 19 according to the prediction mode of the encoding target block, and outputs the predicted image to the subtracter 11 and the adder 15.

  The motion vector detection unit 21 detects a motion vector using the input image and the reference image output from the decoded picture memory 18 and outputs the detected motion vector to the motion vector memory 22 and the inter motion information generation unit 23. The motion vector memory 22 stores the output from the motion vector detection unit 21 or the intra motion information generation unit 24, and is referred to by the inter motion information generation unit 23 or the intra motion information generation unit 24 when deriving a predicted motion vector.

  The inter motion information generation unit 23 generates motion information in the inter prediction mode based on the data input from the motion vector detection unit 21 and the motion vector memory 22 and outputs the motion information to the variable length encoding unit 13. The intra motion information generation unit 24 generates motion information in the intra prediction mode based on the data input from the motion vector memory 22 and outputs the motion information to the motion vector memory 22.

  Next, the video decoding apparatus in the first embodiment will be described with reference to FIG. This video decoding apparatus decodes the encoded data encoded by the video encoding apparatus shown in FIG. FIG. 3 is a block diagram showing the configuration of the video decoding apparatus in the first embodiment. The decoding target input encoded data is input to the video decoding device 4, and is repeatedly decoded for each decoding target block, and a decoded signal is output.

  The variable length decoding unit 41 performs variable length decoding on the input encoded data to obtain a decoding parameter including a transform quantization coefficient and a difference motion vector, and the transform quantization coefficient is sent to the inverse quantization / inverse orthogonal transform unit 42. The difference motion vector is output to the inter motion information generation unit 51. The inverse quantization / inverse quantization unit 42 performs inverse quantization / inverse orthogonal transform on the transform quantization coefficient output from the variable length decoding unit 41, and outputs a decoded residual image to the adder 43.

  The adder 43 obtains a decoded image from the sum of the decoded residual image output from the inverse quantization / inverse orthogonal transform unit 42 and the predicted image obtained from the intra prediction unit 45 or the inter prediction unit 46, and outputs the decoded image as a decoded video. At the same time, the data is output to the loop filter unit 47 and the intra prediction unit 45. The loop filter unit 47 applies a loop filter to the decoded image obtained from the adder 43 and outputs it to the decoded picture memory.

  The decoded picture memory 48 stores the output of the loop filter unit 47, is input to the inter prediction unit 46, and is used as a reference image at the time of subsequent inter prediction of the decoding target block. The intra prediction unit 45 generates an intra prediction image of a later decoding target block using the decoded image output from the adder 43 as a reference image. The inter prediction unit 46 generates an inter prediction image of the decoding target block using the reference image in the decoded picture memory 48 and the motion vector obtained from the motion vector memory 49.

  The intra / inter switch 44 switches the intra prediction unit 45 or the inter prediction unit 46 according to the prediction mode of the decoding target block, and outputs the predicted image to the adder 43. The motion vector memory 49 stores the output from the inter motion information generating unit 51 or the intra motion information generating unit 50, and the inter motion information generating unit 51 or the intra motion information generating unit at the time of prediction and prediction motion vector derivation by the inter prediction unit 46. 50.

  The inter motion information generation unit 51 generates inter prediction mode motion information based on the difference motion vector input from the variable length decoding unit 41 and the data input from the motion vector memory, and outputs the motion information to the motion vector memory 49. The intra motion information generation unit 50 generates motion information in the intra prediction mode based on the data input from the motion vector memory 49 and outputs the motion information to the motion vector memory 49.

  Next, the inter motion information generation unit in the first embodiment will be described with reference to FIGS. 4 and 5. FIG. 4 is a block diagram illustrating a configuration of the inter motion information generation unit 23 in the video encoding device according to the first embodiment. The predicted motion vector candidate list generation unit 231 generates a predicted motion vector candidate list from the motion vectors of the candidate blocks around the encoding target block or the encoded frame input from the motion vector memory 22, and the predicted motion vector determination unit 232. Output to. The predicted motion vector determination unit 232 determines a predicted motion vector from the predicted motion vector candidate list input from the predicted motion vector candidate list generation unit 231.

  In the determination of the motion vector predictor, a motion vector difference between the motion vector of the target block and each candidate of the motion vector predictor candidate list is calculated, and the motion vector predictor index and the prediction with the smallest sum of the code amount of each component of the motion vector difference are calculated. A motion vector is determined. The subtraction unit 233 calculates a differential motion vector between the motion vector input from the motion vector detection unit 21 and the predicted motion vector determined by the predicted motion vector determination unit 232, and together with the reference image list, the reference image index, and the predicted motion vector index. The data is output to the variable length coding unit 13.

  FIG. 5 is a block diagram illustrating a configuration of the inter motion information generation unit 51 in the video decoding apparatus according to the first embodiment. The motion vector predictor candidate list generation unit 511 generates a motion vector predictor candidate list from the motion vector of the candidate block around the decoding target block or the decoded frame input from the motion vector memory 49 and outputs the motion vector candidate list to the motion vector predictor output unit 512. To do. The motion vector predictor output unit 512 outputs a motion vector predictor corresponding to the motion vector predictor index decoded by the variable length decoding unit 41 from the motion vector predictor candidate list input from the motion vector predictor candidate list generation unit 511. The adding unit 513 calculates a motion vector that is the sum of the differential motion vector input from the variable length decoding unit 41 and the predicted motion vector output from the predicted motion vector output unit 512, and outputs the motion vector to the motion vector memory 49.

  Next, the intra motion information generation unit 24 that is a feature of the present invention will be described with reference to FIG. FIG. 6 is a block diagram illustrating a configuration of the intra motion information generation unit 24 in the first embodiment. The intra motion information generation unit 24 is a component that is not present in the prior art. The predicted motion vector candidate list generation unit 241 generates a predicted motion vector candidate list from the motion vector of the candidate block of the encoded or decoded target block around the encoded or decoded block input from the motion vector memory 22, and sets prediction The result is output to the motion vector determination unit 242. The set predicted motion vector determination unit 242 outputs a predetermined predicted motion vector from the predicted motion vector candidate list to the motion vector memory 22.

  Next, a motion vector setting processing operation in the first embodiment will be described with reference to FIG. FIG. 7 is a flowchart showing the motion vector setting processing operation in the first embodiment. First, it is determined whether or not the prediction mode of the target block is the inter prediction mode (step S1). If the determination result is the inter prediction mode, the motion vector of the target block is set as the motion vector of the target block in the motion vector memory. (Step S2). Otherwise, a predetermined predicted motion vector is set in the motion vector memory as the motion vector of the target block from the predicted motion vector candidate list (step S3). As the motion vector predictor to be set, a motion vector predictor corresponding to a motion vector predictor index set in advance is used.

  Next, processing operations of the motion vector predictor candidate list generation units 232, 511, and 241 illustrated in FIGS. 4, 5, and 6 will be described with reference to FIG. FIG. 8 is a flowchart showing processing operations of the motion vector predictor candidate list generation units 232, 511, and 241 shown in FIGS.

First, the candidate blocks are scanned in a predetermined priority order (step S11). The candidate block is a block group shown in FIGS. The priority order is as follows.
・ Scan in the order of A0⇒A1⇒B0⇒B1⇒B2⇒H (C3) ・ Priority is given to motion vectors that have the same reference image as the reference image of the target block

  It is determined whether or not the total number of motion vector predictor candidate lists is less than 2 (step S12). If the total number is less than 2, it is determined whether the reference pixels of the target block and the candidate block are the same (step S13). If the reference pixels are not the same as a result of this determination, scaling is performed according to the distance between the reference images (step S14).

  Next, whether the motion vector of the candidate block is already added to the list in each block group (A0, A1 is the block group A, and B0, B1, B2 is the block group B). An overlap determination is made (step S15). If there is no overlap, if the reference image of the candidate block is different from the reference image of the target block to be encoded (or decoded) for the motion vector of the candidate block, depending on the distance between the reference images After performing the scaling process, it is added to the list (step S16). When scanning for all candidate blocks is completed (step S17), it is determined whether the total number of motion vector predictor candidate lists is less than 2 (step S18). If the total number is less than 2, a zero vector is added to the rest of the list (step S19).

  For reference, the operation of the motion vector predictor candidate list generation unit in the prior art is shown in FIG. In FIG. 9, the same reference numerals are given to the same processing operations as those shown in FIG. The conventional technique is different in that a process (step S111) for determining whether or not the reference image index of the scanned candidate block is 0 or more (that is, inter prediction) is added. Further, although description of merge encoding is omitted in the present embodiment, the present invention can be applied to the conventional merge candidate list generation by executing the processing operation of the same procedure. .

(Difference between this embodiment and conventional technology and effects obtained)
This embodiment is different from the prior art in the present embodiment. In this embodiment, when the target block is in the intra prediction mode, the prediction motion vector is set in the motion vector memory. Therefore, when the prediction motion vector is derived, the candidate block is intra predicted. Even in the mode, it is possible to add to the motion vector predictor candidate list. In the prior art, it is not added in the case of the intra prediction mode. This increases the possibility that the motion vector predictor candidate added to the motion vector predictor candidate list is not a zero vector, and the motion vector difference from the motion vector of the block to be encoded can be reduced.

  For example, in the situation shown in FIG. 21, if the current block has the same motion vector as that of the region encoded in the inter prediction mode, the predicted motion vector candidate list derived by the conventional technique has zero. Since only the vector is added, the code amount of the differential motion vector of the target block cannot be reduced. However, when this embodiment is used, the coding is performed in the region encoded in the intra prediction mode around the encoding target block. Since the motion vector of the region to be encoded in the prediction mode is set and the motion vector is added to the prediction motion vector candidate list derived by the target block, the amount of code of the differential motion vector of the target block to be encoded is set. Can be small. Since the same processing as in encoding is performed in decoding, the same motion vector predictor as in encoding can be referred to.

  Thus, in the first embodiment, when the target block is in the intra prediction mode, a predetermined motion vector predictor is set as the motion vector of the target block from the motion vector predictor candidate list. Then, at the time of deriving the motion vector predictor candidate list, reference is made to the motion vector set even when the candidate block is in the intra prediction mode.

<Second Embodiment>
With reference to FIG.10 and FIG.11, the video encoding apparatus and video decoding apparatus in 2nd Embodiment are demonstrated. FIG. 10 is a block diagram showing the configuration of the video encoding apparatus in the second embodiment. FIG. 11 is a block diagram showing the configuration of the video decoding apparatus in the second embodiment. This embodiment demonstrates the point which added the change to 1st Embodiment. The video encoding device 1 (FIG. 10) and the video decoding device 4 (FIG. 11) are different in that candidate block prediction mode determination units 25 and 52 are added. Only differences from the first embodiment will be described below.

  The candidate block prediction mode determination units 25 and 52 in the second embodiment use the inter motion information generation unit 23 as a prediction mode determination result of each candidate block when generating a motion vector predictor candidate list based on the encoding result or the decoded data. , 51 and the intra motion information generating units 24, 50.

  Next, with reference to FIG.12 and FIG.13, the inter motion information generation parts 23 and 51 in 2nd Embodiment are demonstrated. FIG. 12 is a block diagram illustrating a configuration of the inter motion information generation unit 23 in the second embodiment. FIG. 13 is a block diagram illustrating a configuration of the inter motion information generation unit 51 in the second embodiment. The difference from the first embodiment is that the determination results are input from the candidate block prediction mode determination units 25 and 52 to the prediction motion vector candidate list generation units 231 and 511.

  Next, with reference to FIG. 14, the intra motion information generation units 24 and 50 in the second embodiment will be described. FIG. 14 is a block diagram illustrating a configuration of the intra motion information generation units 24 and 50 in the second embodiment. The difference from the first embodiment is that the determination results are input from the candidate block prediction mode determination units 25 and 52 to the motion vector predictor candidate list generation unit 241.

  Next, processing operations of the motion vector predictor candidate list generation units 231, 512, and 241 illustrated in FIGS. 12, 13, and 14 will be described with reference to FIGS. 15 and 16. FIGS. 15 and 16 are flowcharts showing processing operations of the motion vector predictor candidate list generation units 231, 512 and 241 shown in FIGS. 12, 13 and 14. FIG. 15 shows the processing operation of the process A part in FIG. First, the processing operation of processing A will be described. The processing operation of processing A is similar to the processing operation shown in FIG.

First, the candidate blocks are scanned in a predetermined priority order (step S21). The candidate block is a block group shown in FIGS. The priority order is as follows.
・ Scan in the order of A0⇒A1⇒B0⇒B1⇒B2⇒H (C3) ・ Priority is given to motion vectors that have the same reference image as the reference image of the target block

  It is determined whether or not the total number of motion vector predictor candidate lists is less than 2 (step S22). If the total number is less than 2, it is determined whether or not the reference pixels of the target block and the candidate block are the same (step S23). If the reference pixels are not the same as a result of this determination, scaling is performed according to the distance between the reference images (step S24).

  Next, whether the motion vector of the candidate block is already added to the list in each block group (A0, A1 is the block group A, and B0, B1, B2 is the block group B). An overlap determination is performed (step S25). If there is no overlap, if the reference image of the candidate block is different from the reference image of the target block to be encoded (or decoded) for the motion vector of the candidate block, depending on the distance between the reference images After performing the scaling process, it is added to the list (step S26). Then, all candidate blocks are scanned (step S27).

  Next, processing operations of the motion vector predictor candidate list generation units 231, 512, and 241 will be described with reference to FIG. First, candidate block groups in the inter prediction mode are extracted from candidate blocks derived from the periphery of the target block, and processing A is performed on these candidate block groups (step S31). Process A is the process described above. It is determined whether or not the total number of motion vector predictor candidate lists is less than 2 (step S32). If not, candidate block groups in the intra prediction mode are extracted, and processing A is performed on these candidate block groups. Is performed (step S33). As a result of this processing, it is determined whether or not the total number of motion vector predictor candidate lists is less than 2 (step S34), and if not, a zero vector is added to the rest of the list (step S35).

(Difference between this embodiment and conventional technology and effects obtained)
By preferentially adding a block whose candidate block is in inter prediction mode to the list, a highly reliable inter prediction mode motion vector candidate having original motion information is added to the list first. Therefore, the accuracy of the predicted motion vector can be expected to improve.

  Thus, in the second embodiment, when the motion vector predictor candidate list is derived, motion vectors to be added to the list are added with the priority of the candidate block prediction mode “inter prediction mode” → “intra prediction mode”. .

<Third Embodiment>
A video encoding device and a video decoding device according to the third embodiment will be described. In the present embodiment, a case where a change is made to the first embodiment will be described, but the present invention can be similarly applied to the second embodiment. The video encoding device and the video decoding device are the same except for the processing operation of the intra motion information generation unit in FIGS. 1 and 3. Only differences from the first embodiment will be described below.

  With reference to FIG. 17, the intra motion information production | generation parts 24 and 50 in 3rd Embodiment are demonstrated. FIG. 17 is a block diagram illustrating the configuration of the intra motion information generation units 24 and 50 according to the third embodiment. The difference from the first embodiment is that a motion vector statistic calculation unit 243 is added. The motion vector statistic calculation unit 243 calculates a motion vector statistic based on the data from the motion vector memories 22 and 49 and outputs the motion vector statistic to the set prediction motion vector determination unit 242.

  Subsequently, a motion vector setting processing operation in the third embodiment will be described with reference to FIG. FIG. 18 is a flowchart showing the motion vector setting processing operation in the third embodiment. The flowchart shown in FIG. 18 differs from the flowchart shown in FIG. 7 in that the operation is different when the prediction mode of the target block is not the inter prediction mode. In FIG. 18, the same reference numerals are given to the same operations as those shown in FIG. It is determined whether the prediction mode of the target block is not the inter prediction mode (step S1). If the prediction mode is not the inter prediction mode, a motion vector statistic is calculated (step S4), and a predicted motion vector is calculated based on the calculated statistic. A predicted motion vector to be set as a motion vector of the target block is determined from the candidate list (step S5). Various variations are conceivable for the method of determining the statistics to be calculated and the predicted motion vector to be set. An example of the variation is shown below.

(Variation 1: Absolute sum of each component is maximum)
The absolute sum (L1 norm) of each component is calculated as a statistic for each predicted motion vector in the predicted motion vector candidate list, and the predicted motion vector having the largest value is selected. By doing so, a vector whose predicted motion vector to be set is different from the zero vector is easily selected, and the possibility that the code amount of the difference motion vector is further reduced is increased.

(Variation 2: Mode value among candidate blocks)
A predicted motion vector that appears most frequently in the candidate block group is calculated as a statistic, and the predicted motion vector is selected as a predicted motion vector to be set. However, if they are all different, the smaller predicted motion vector index is used. Since the mode value is considered to be a motion vector having the same surrounding area in the candidate block group, it is possible to select a reliable vector, and there is a high possibility that the code amount of the difference motion vector is made smaller. Become.

(Variation 3: Median value among candidate blocks)
The median value of each component in the candidate block group is calculated as a statistic, and those values are set as a predicted motion vector. In this way, it is possible to set an appropriate predicted motion vector even when there is an outlier in the candidate block group, and the possibility of further reducing the code amount of the difference motion vector is increased.

(Difference between this embodiment and conventional technology and effects obtained)
When the prediction mode of the target block is the intra prediction mode, it is possible to set a highly reliable predicted motion vector according to the condition based on the motion vector statistic from the predicted motion vectors, so the accuracy of the predicted motion vector is improved. Can be expected.

  Thus, in the third embodiment, the predicted motion vector set when the target block is in the intra prediction mode is a predicted motion vector that satisfies a predetermined condition based on the statistics of the motion vector.

  In addition, you may make it select and decode what was encoded by the video encoding apparatus mentioned above. Further, when a data loss related to a block encoded by transmission occurs, the motion vector of the previous block may be used, or a zero vector may be inserted instead.

  As described above, when encoding and decoding moving images, particularly inter prediction, if a block is encoded in the intra prediction mode in the prior art, a motion vector is not stored, and another block is When encoding is performed in the prediction mode, a block encoded in the intra prediction mode cannot be used for prediction. In this embodiment, even when intra prediction is performed on a block, it is possible to refer to an adjacent block and leave the motion vector information so that reference can be made even when another block is encoded in the inter prediction mode, thereby improving encoding efficiency. Can be made.

  You may make it implement | achieve all or one part of the video encoding apparatus and video decoding apparatus in embodiment mentioned above with a computer. In that case, a program for realizing this function may be recorded on a computer-readable recording medium, and the program recorded on this recording medium may be read into a computer system and executed. Here, the “computer system” includes an OS and hardware such as peripheral devices. The “computer-readable recording medium” refers to a storage device such as a flexible medium, a magneto-optical disk, a portable medium such as a ROM and a CD-ROM, and a hard disk incorporated in a computer system. Furthermore, the “computer-readable recording medium” dynamically holds a program for a short time like a communication line when transmitting a program via a network such as the Internet or a communication line such as a telephone line. In this case, a volatile memory inside a computer system serving as a server or a client in that case may be included and a program held for a certain period of time. Further, the program may be a program for realizing a part of the above-described functions, and may be a program capable of realizing the functions described above in combination with a program already recorded in a computer system. It may be realized using hardware such as PLD (Programmable Logic Device) or FPGA (Field Programmable Gate Array).

  As mentioned above, although embodiment of this invention has been described with reference to drawings, the said embodiment is only the illustration of this invention, and it is clear that this invention is not limited to the said embodiment. is there. Therefore, additions, omissions, substitutions, and other modifications of the components may be made without departing from the technical idea and scope of the present invention.

  The present invention can be applied to an application in which it is indispensable to prevent deterioration of the accuracy of a predicted image while suppressing deterioration in encoding efficiency.

  DESCRIPTION OF SYMBOLS 1 ... Video coding apparatus, 11 ... Subtractor, 12 ... Orthogonal transformation / quantization part, 13 ... Variable length coding part, 14 ... Dequantization / inverse orthogonal transformation part, DESCRIPTION OF SYMBOLS 15 ... Adder, 16 ... Loop filter part, 17 ... Intra prediction part, 18 ... Decoded picture memory, 19 ... Inter prediction part, 20 ... Intra / inter changeover switch, 21 ... Motion vector detection unit, 22 ... Motion vector memory, 23 ... Inter motion information generation unit, 24 ... Intra motion information generation unit, 4 ... Video decoding device, 41 ... Variable length Decoding unit, 42... Inverse quantization / inverse orthogonal transform unit, 43... Adder unit, 44... Intra / inter changeover switch, 45. ... Loop filter unit, 48 ... Decoding pin Chamemori, 49 ... motion vector memory, 50 ... intra motion information generation unit, 51 ... inter motion information generating unit

Claims (18)

A video encoding device that encodes video in units of blocks using intra prediction and inter prediction,
Predicted motion vector deriving means for deriving predicted motion vector candidates from candidate blocks around the target block;
A video encoding device comprising: a prediction motion vector setting unit configured to set a prediction motion vector derived by the prediction motion vector deriving unit as a motion vector of the target block when an intra prediction mode is selected in the target block.   The predicted motion vector deriving unit refers to a motion vector set by the predicted motion vector setting unit as a predicted motion vector candidate of the target block when the candidate block is in the intra prediction mode. Video encoding device.   The prediction motion vector deriving unit determines whether the prediction mode is the inter prediction mode in a predetermined order from the surrounding of the target block or the encoded block of the encoded frame, and predicts motion from the candidate block that is the inter prediction mode. The video encoding apparatus according to claim 2, wherein a vector candidate is derived, and when the number of motion vector predictor candidates is less than a predetermined value, a motion vector predictor candidate is derived from the candidate block that is not in the inter prediction mode.   4. The video encoding apparatus according to claim 2, wherein the predicted motion vector setting means sets a predicted motion vector candidate that satisfies a predetermined condition based on a motion vector statistic from the derived predicted motion vector candidates.   The video encoding apparatus according to claim 4, wherein the condition is that a sum of absolute values of each element of the motion vector is maximum.   The video encoding device according to claim 4, wherein the condition is a mode motion vector around the target block or in an encoded block of an encoded frame. A video decoding device that decodes encoded data obtained by encoding a video block by block using intra prediction and inter prediction,
Predicted motion vector deriving means for deriving predicted motion vector candidates from candidate blocks around the target block;
When the intra prediction mode is selected in the target block, a video decoding device comprising: a predicted motion vector setting unit that sets a predicted motion vector derived by the predicted motion vector deriving unit as a motion vector of the target block.   8. The predicted motion vector deriving unit refers to a motion vector set by the predicted motion vector setting unit as a predicted motion vector candidate of the target block when the candidate block is in the intra prediction mode. Video decoding device.   The prediction motion vector deriving unit determines whether the prediction mode is the inter prediction mode in a predetermined order from the surrounding of the target block or the encoded block of the encoded frame, and predicts from the candidate block that is the inter prediction mode. 9. The video decoding apparatus according to claim 8, wherein a motion vector candidate is derived, and when the number of motion vector predictor candidates is less than a predetermined value, a motion vector predictor candidate is derived from the candidate block that is not in the inter prediction mode.   10. The video decoding apparatus according to claim 8, wherein the predicted motion vector setting means sets a predicted motion vector candidate that satisfies a predetermined condition based on a motion vector statistic from the derived predicted motion vector candidates.   The video decoding apparatus according to claim 10, wherein the condition is that a sum of absolute values of each element of the motion vector is maximum.   The video decoding apparatus according to claim 10, wherein the condition is a mode motion vector around the target block or in an encoded block of an encoded frame. A video encoding method performed by a video encoding device that encodes video in units of blocks using intra prediction and inter prediction,
A prediction motion vector derivation step for deriving a prediction motion vector candidate from candidate blocks around the target block;
A prediction motion vector setting step of setting a prediction motion vector derived by the prediction motion vector derivation step as a motion vector of the target block when an intra prediction mode is selected in the target block;   The prediction motion vector derivation step refers to the motion vector set in the prediction motion vector setting step as a prediction motion vector candidate of the target block when the candidate block is in the intra prediction mode. Video encoding method. A video decoding method performed by a video decoding device that decodes encoded data obtained by encoding a video block by block using intra prediction and inter prediction,
A prediction motion vector derivation step for deriving a prediction motion vector candidate from candidate blocks around the target block;
And a prediction motion vector setting step of setting a prediction motion vector derived by the prediction motion vector derivation step as a motion vector of the target block when an intra prediction mode is selected in the target block.   16. The prediction motion vector deriving step refers to the motion vector set in the prediction motion vector setting step as a prediction motion vector candidate of the target block when the candidate block is in the intra prediction mode. Video decoding method.   A video encoding program for causing a computer to function as the video encoding device according to any one of claims 1 to 6.   A video decoding program for causing a computer to function as the video decoding device according to any one of claims 7 to 12.

Images