Encoding device, decoding device, and method for transmitting a bitstream

Abstract

To suppress delay of processing.SOLUTION: In inter prediction processing, deriving a first motion vector of a first current processing target block by using a motion vector of a past processing target block, deriving a second motion vector of the first current processing target block by performing motion search processing on a peripheral region of the first motion vector, generating a prediction image of the first current processing target block by motion compensation using the second motion vector, and deriving a third motion vector of a second current processing target block that is a processing target block after the first current processing target block by using the first motion vector, A fourth motion vector of the second current processing target block is derived by performing motion search processing on a peripheral area of the third motion vector, and a prediction image of the second current processing target block is generated by motion compensation using the fourth motion vector.SELECTED DRAWING: Figure 15

Description

[Technical Field]

[0001] This disclosure relates to an encoding device, a decoding device, an encoding method, and a decoding method. [Background technology]

[0002] Traditionally, H.265 has been used as a standard for encoding moving images. H.265 is also known as HEVC (High Efficiency Video Coding). [Prior art documents] [Non-patent literature]

[0003] [Non-Patent Document 1] H.265(ISO / IEC 23008-2 HEVC(High Efficiency Video Coding)) [Overview of the project] [Problems that the invention aims to solve]

[0004] In such encoding and decoding methods, it is desirable to be able to suppress processing delays.

[0005] This disclosure aims to provide a decoding device, encoding device, decoding method, or encoding method that can suppress processing delays. [Means for solving the problem]

[0006] An encoding device according to one aspect of the present disclosure comprises a circuit and a memory, wherein the circuit, using the memory, in inter-prediction processing, derives a first motion vector of a first target block using the motion vectors of past target blocks, derives a second motion vector of the first target block by performing motion search processing on the surrounding region of the first motion vector, generates a predicted image of the first target block by motion compensation using the second motion vector, if a second target block, which is a target block processed after the first target block, belongs to the same picture as the first target block, derives a third motion vector of the second target block using the first motion vector of the first target block shown in the motion vector list, if the second target block belongs to a different picture from the first target block, derives a third motion vector of the second target block using the second motion vector of the first target block shown in the motion vector list, derives a fourth motion vector of the second target block by performing motion search processing on the surrounding region of the third motion vector, and generates a predicted image of the second target block by motion compensation using the fourth motion vector. Furthermore, the first motion vector is used in loop filtering. .

[0007] These comprehensive or specific embodiments may be implemented as systems, devices, methods, integrated circuits, computer programs, or non-temporary recording media such as computer-readable CD-ROMs, or as any combination of systems, devices, methods, integrated circuits, computer programs, and recording media. [Effects of the Invention]

[0008] This disclosure can provide a decoding device, an encoding device, a decoding method, or an encoding method that can suppress processing delays. [Brief explanation of the drawing]

[0009] [Figure 1]Figure 1 is a block diagram showing the functional configuration of the encoding device according to Embodiment 1. [Figure 2] Figure 2 shows an example of block division in Embodiment 1. [Figure 3] Figure 3 is a table showing the transformation basis functions corresponding to each transformation type. [Figure 4A] Figure 4A shows an example of the filter shape used in ALF. [Figure 4B] Figure 4B shows another example of the filter shape used in ALF. [Figure 4C] Figure 4C shows another example of the filter shape used in ALF. [Figure 5A] Figure 5A shows the 67 intra-prediction modes in intra-prediction. [Figure 5B] Figure 5B is a flowchart illustrating the overview of the predictive image correction process using OBMC processing. [Figure 5C] Figure 5C is a conceptual diagram illustrating the overview of the predictive image correction process using OBMC processing. [Figure 5D] Figure 5D shows an example of FRUC. [Figure 6] Figure 6 is a diagram illustrating pattern matching (bilateral matching) between two blocks along a motion trajectory. [Figure 7] Figure 7 illustrates pattern matching (template matching) between a template in the current picture and a block in the referenced picture. [Figure 8] Figure 8 is a diagram illustrating a model that assumes uniform linear motion. [Figure 9A] Figure 9A is a diagram illustrating the derivation of subblock-level motion vectors based on the motion vectors of multiple adjacent blocks. [Figure 9B] Figure 9B is a diagram illustrating the overview of the motion vector derivation process using merge mode. [Figure 9C]FIG. 9C is a conceptual diagram for explaining an overview of DMVR processing. [Figure 9D] FIG. 9D is a diagram for explaining an overview of a predicted image generation method using luminance correction processing by LIC processing. [Figure 10] FIG. 10 is a block diagram showing a functional configuration of the decoding device according to the first embodiment. [Figure 11] FIG. 11 is a schematic diagram showing a first example of a pipeline structure according to the first embodiment. [Figure 12] FIG. 12 is a schematic diagram showing an example of block division used for explaining pipeline processing according to the first embodiment. [Figure 13] FIG. 13 is a time chart showing an example of processing timing in the first example of the pipeline structure according to the first embodiment. [Figure 14] FIG. 14 is a flowchart of inter prediction processing in the first example of the pipeline configuration according to the first embodiment. [Figure 15] FIG. 15 is a schematic diagram showing a second example of the pipeline structure according to the first embodiment. [Figure 16] FIG. 16 is a time chart showing an example of processing timing in the second example of the pipeline structure according to the first embodiment. [Figure 17] FIG. 17 is a flowchart of inter prediction processing in the second example of the pipeline configuration according to the first embodiment. [Figure 18] FIG. 18 is a schematic diagram showing a third example of the pipeline structure according to the first embodiment. [Figure 19] FIG. 19 is a time chart showing an example of processing timing in the third example of the pipeline structure according to the first embodiment. [Figure 20] FIG. 20 is a flowchart of inter prediction processing in the third example of the pipeline configuration according to the first embodiment. [Figure 21] FIG. 21 is a diagram showing an example of a reference motion vector according to the first embodiment. [Figure 22]Figure 22 shows an example of a reference motion vector according to Embodiment 1. [Figure 23] Figure 23 is a block diagram showing an example of an encoding device implementation. [Figure 24] Figure 24 is a block diagram showing an example implementation of a decoding device. [Figure 25] Figure 25 is an overall diagram of the content supply system that enables the content distribution service. [Figure 26] Figure 26 shows an example of an encoding structure during scalable encoding. [Figure 27] Figure 27 shows an example of an encoding structure during scalable encoding. [Figure 28] Figure 28 shows an example of how a web page is displayed. [Figure 29] Figure 29 shows an example of how a web page is displayed. [Figure 30] Figure 30 shows an example of a smartphone. [Figure 31] Figure 31 is a block diagram showing an example of a smartphone configuration. [Modes for carrying out the invention]

[0010] An encoding device according to one aspect of the present disclosure comprises a circuit and a memory, wherein the circuit, using the memory, encodes a target block in an inter-prediction mode in which motion search is performed in a decoding device, derives a first motion vector of the target block, stores the derived first motion vector in the memory, derives a second motion vector of the target block, generates a predicted image of the target block by motion compensation using the second motion vector, and in the derivation of the first motion vector, the first motion vector of the target block is derived using the first motion vector of a processed block.

[0011] According to this, in pipeline control, the decoder can, for example, start deriving the first motion vector of the target block after the completion of deriving the first motion vector of the surrounding block, without waiting for the completion of deriving the second motion vector of the surrounding block. Therefore, compared to the case where the first motion vector is derived using the second motion vector of the surrounding block, the waiting time in the pipeline control of the decoder can be reduced, and thus the processing delay can be reduced.

[0012] For example, in the derivation of the first motion vector, (i) a list of predicted motion vectors showing a plurality of predicted motion vectors may be generated using the first motion vector of the processed block, and (ii) the first motion vector of the target block may be determined from the plurality of predicted motion vectors shown in the list of predicted motion vectors.

[0013] For example, the interpretation mode used for motion search in the decoding device is a merge mode, and the second motion vector may be derived by performing motion search processing on the vicinity of the first motion vector.

[0014] For example, the interpretation mode used in the decoding device for motion search is the FRUC mode, and the second motion vector may be derived by performing a motion search operation on the vicinity of the first motion vector.

[0015] For example, the interpretation mode used in motion search by the decoding device is the FRUC mode, and in the derivation of the second motion vector, (i) a third motion vector may be determined from the plurality of predicted motion vectors shown in the predicted motion vector list, and (ii) the second motion vector may be derived by performing motion search processing around the third motion vector.

[0016] For example, in determining the first motion vector, the first motion vector may be derived based on the average or median value for each prediction direction of the plurality of prediction motion vectors shown in the prediction motion vector list.

[0017] For example, in determining the first motion vector, the first motion vector may be the one shown at the beginning of the list of predicted motion vectors, from among the plurality of predicted motion vectors shown in the list of predicted motion vectors.

[0018] For example, in generating the predicted motion vector list, each of the plurality of predicted motion vectors may be derived using the first motion vector or the second motion vector of the processed block, and in determining the first motion vector, the first motion vector may be determined from among the plurality of predicted motion vectors shown in the predicted motion vector list, from among the candidate predicted motion vectors derived using the second motion vector.

[0019] According to this, the encoding device can determine the first motion vector using a highly reliable second motion vector, thereby suppressing a decrease in the reliability of the first motion vector.

[0020] For example, in generating the predicted motion vector list, each of the plurality of predicted motion vectors may be derived using the first motion vector or second motion vector of the processed block. If the processed block belongs to the same picture as the target block, the predicted motion vector may be derived using the first motion vector of the processed block. If the processed block belongs to a different picture from the target block, the predicted motion vector may be derived using the second motion vector of the processed block.

[0021] According to this, the encoding device can improve the reliability of the predicted motion vector by using a second motion vector when the processed block belongs to a different picture than the target block.

[0022] For example, in generating the predicted motion vector list, each of the plurality of predicted motion vectors may be derived using the first motion vector or the second motion vector of the processed block, and depending on the position of the processed block relative to the target block, it may be decided whether to use the first motion vector of the processed block or the second motion vector of the processed block in deriving the predicted motion vector.

[0023] For example, in generating the predicted motion vector list, among multiple processed blocks belonging to the same picture as the target block, the first motion vector of the processed block is used to derive the predicted motion vector for the processed block that is N steps prior in processing order to the target block, and for processed blocks that are N steps prior in processing order and later, and for processed blocks that are N steps prior in processing order and earlier, the second motion vector of the processed block is used to derive the predicted motion vector.

[0024] According to this, the encoding device can improve the reliability of the predicted motion vector by using a second motion vector for processed blocks that are N processed blocks prior in the processing order.

[0025] For example, N may be 1.

[0026] For example, the first motion vector may be referenced in processes other than the derivation of the predicted motion vector.

[0027] For example, the other processing may be loop filtering.

[0028] For example, the second motion vector may be used in loop filtering.

[0029] For example, when encoding the target block in low-latency mode, the first motion vector of the target block may be derived using the first motion vector of the processed block.

[0030] According to this, the encoding device can perform appropriate processing depending on whether or not it uses a low-latency mode.

[0031] For example, information indicating whether or not to encode the target block in the low-latency mode may be encoded in the sequence header area, picture header area, slice header area, or auxiliary information area.

[0032] For example, depending on the size of the target picture including the target block, it may be possible to switch whether or not to encode the target block in the low-latency mode.

[0033] For example, depending on the processing capacity of the decoding device, it may be possible to switch whether or not to encode the target block in the low-latency mode.

[0034] For example, depending on the profile or level information assigned to the stream to be encoded, it may be possible to switch whether or not to encode the target block in the low-latency mode.

[0035] A decoding device according to one aspect of the present disclosure is a decoding device comprising a circuit and a memory, wherein the circuit, using the memory, decodes a target block in an inter-prediction mode in which motion search is performed in the decoding device, derives a first motion vector of the target block, stores the derived first motion vector in the memory, derives a second motion vector of the target block, generates a predicted image of the target block by motion compensation using the second motion vector, and in the derivation of the first motion vector, derives the first motion vector of the target block using the first motion vector of a processed block.

[0036] According to this, in pipeline control, the decoding device can, for example, start deriving the first motion vector of the target block after the completion of deriving the first motion vector of the surrounding block, without waiting for the completion of deriving the second motion vector of the surrounding block. Therefore, compared to the case where the first motion vector is derived using the second motion vector of the surrounding block, the waiting time in the decoding device's pipeline control can be reduced, thereby reducing processing delays.

[0037] For example, in the derivation of the first motion vector, (i) a list of predicted motion vectors showing a plurality of predicted motion vectors may be generated using the first motion vector of the processed block, and (ii) the first motion vector of the target block may be determined from the plurality of predicted motion vectors shown in the list of predicted motion vectors.

[0038] For example, the interpretation mode used for motion search in the decoding device is a merge mode, and the second motion vector may be derived by performing motion search processing on the vicinity of the first motion vector.

[0039] For example, the interpretation mode used in the decoding device for motion search is the FRUC mode, and the second motion vector may be derived by performing a motion search operation on the vicinity of the first motion vector.

[0040] For example, the interpretation mode used in motion search by the decoding device is the FRUC mode, and in the derivation of the second motion vector, (i) a third motion vector may be determined from the plurality of predicted motion vectors shown in the predicted motion vector list, and (ii) the second motion vector may be derived by performing motion search processing around the third motion vector.

[0041] For example, in determining the first motion vector, the first motion vector may be derived based on the average or median value for each prediction direction of the plurality of prediction motion vectors shown in the prediction motion vector list.

[0042] For example, in determining the first motion vector, the first motion vector may be the one shown at the beginning of the list of predicted motion vectors, from among the plurality of predicted motion vectors shown in the list of predicted motion vectors.

[0043] For example, in generating the predicted motion vector list, each of the plurality of predicted motion vectors may be derived using the first motion vector or the second motion vector of the processed block, and in determining the first motion vector, the first motion vector may be determined from among the plurality of predicted motion vectors shown in the predicted motion vector list, from among the candidate predicted motion vectors derived using the second motion vector.

[0044] According to this, the decoding device can determine the first motion vector using a highly reliable second motion vector, thereby suppressing a decrease in the reliability of the first motion vector.

[0045] For example, in generating the predicted motion vector list, each of the plurality of predicted motion vectors may be derived using the first motion vector or second motion vector of the processed block. If the processed block belongs to the same picture as the target block, the predicted motion vector may be derived using the first motion vector of the processed block. If the processed block belongs to a different picture from the target block, the predicted motion vector may be derived using the second motion vector of the processed block.

[0046] According to this, the decoding device can improve the reliability of the predicted motion vector by using a second motion vector when the processed block belongs to a different picture than the target block.

[0047] For example, in generating the predicted motion vector list, each of the plurality of predicted motion vectors may be derived using the first motion vector or the second motion vector of the processed block, and depending on the position of the processed block relative to the target block, it may be decided whether to use the first motion vector of the processed block or the second motion vector of the processed block in deriving the predicted motion vector.

[0048] For example, in generating the predicted motion vector list, among multiple processed blocks belonging to the same picture as the target block, the first motion vector of the processed block is used to derive the predicted motion vector for the processed block that is N steps prior in processing order to the target block, and for processed blocks that are N steps prior in processing order and later, and for processed blocks that are N steps prior in processing order and earlier, the second motion vector of the processed block is used to derive the predicted motion vector.

[0049] According to this, the decoding device can improve the reliability of the predicted motion vector by using a second motion vector for processed blocks that are N processed blocks prior in the processing order.

[0050] For example, N may be 1.

[0051] For example, the first motion vector may be referenced in processes other than the derivation of the predicted motion vector.

[0052] For example, the other processing may be loop filtering.

[0053] For example, the second motion vector may be used in loop filtering.

[0054] For example, when decoding the target block in low-latency mode, the first motion vector of the target block may be derived using the first motion vector of the processed block.

[0055] According to this, the decoding device can perform appropriate processing depending on whether or not it uses a low-latency mode.

[0056] For example, information indicating whether or not to decode the target block in the low-latency mode may be decoded from the sequence header area, picture header area, slice header area, or auxiliary information area, and based on this information, it may be determined whether or not to decode the target block in the low-latency mode.

[0057] For example, the pipeline structure of the decoding device includes a first stage that performs a process to derive the first motion vector of the target block, and a second stage, separate from the first stage, that performs a process to derive the second motion vector of the target block. The processing of the first stage of the target block may be started as soon as the processing of the first stage of the immediately preceding block is completed, without waiting for the completion of the processing of the second stage of the blocks up to M blocks prior in processing order.

[0058] For example, the pipeline structure of the decoding device includes a first stage that performs a process to derive the first motion vector of the target block, and a second stage, separate from the first stage, that performs a process to derive the second motion vector of the target block. The processing of the first stage of the target block may be started as soon as the first motion vector of the block M positions prior in processing order is derived, without waiting for the completion of the second stage processing of the blocks up to M positions prior in processing order.

[0059] For example, M may be 1.

[0060] An encoding method according to one aspect of the present disclosure, when encoding a target block in an inter-prediction mode in which motion search is performed in a decoding device, derives a first motion vector of the target block, stores the derived first motion vector in the memory, derives a second motion vector of the target block, generates a predicted image of the target block by motion compensation using the second motion vector, and in the derivation of the first motion vector, the first motion vector of the target block is derived using the first motion vector of a processed block.

[0061] According to this, in pipeline control, the decoder can, for example, start deriving the first motion vector of the target block after the completion of deriving the first motion vector of the surrounding block, without waiting for the completion of deriving the second motion vector of the surrounding block. Therefore, compared to the case where the first motion vector is derived using the second motion vector of the surrounding block, the waiting time in the pipeline control of the decoder can be reduced, and thus the processing delay can be reduced.

[0062] A decoding method according to one aspect of the present disclosure, when decoding a target block in an inter-prediction mode in which motion search is performed in a decoding device, derives a first motion vector of the target block, stores the derived first motion vector in the memory, derives a second motion vector of the target block, generates a predicted image of the target block by motion compensation using the second motion vector, and in deriving the first motion vector, the first motion vector of the target block is derived using the first motion vector of a processed block.

[0063] According to this, in pipeline control, the decoding method can, for example, start deriving the first motion vector of the target block after the completion of deriving the first motion vector of the surrounding block, without waiting for the completion of deriving the second motion vector of the surrounding block. Therefore, compared to the case where the first motion vector is derived using the second motion vector of the surrounding block, the waiting time in the pipeline control of the decoding device can be reduced, and thus the processing delay can be reduced.

[0064] Furthermore, these comprehensive or specific embodiments may be implemented as systems, devices, methods, integrated circuits, computer programs, or non-temporary recording media such as computer-readable CD-ROMs, or as any combination of systems, devices, methods, integrated circuits, computer programs, and recording media.

[0065] The embodiments will be described in detail below with reference to the drawings.

[0066] The embodiments described below are all comprehensive or specific examples. The numerical values, shapes, materials, components, arrangement and connection configurations of components, steps, and the order of steps shown in the following embodiments are examples only and are not intended to limit the scope of the claims. Furthermore, among the components in the following embodiments, those not described in the independent claim representing the highest-level concept will be described as optional components.

[0067] (Embodiment 1) First, an overview of Embodiment 1 will be given as an example of an encoding and decoding device to which the processes and / or configurations described in each aspect of this disclosure, described later, can be applied. However, Embodiment 1 is merely an example of an encoding and decoding device to which the processes and / or configurations described in each aspect of this disclosure can be applied, and the processes and / or configurations described in each aspect of this disclosure can also be implemented in encoding and decoding devices different from Embodiment 1.

[0068] When applying the processes and / or configurations described in each aspect of this disclosure to Embodiment 1, for example, one of the following may be performed:

[0069] (1) With respect to the encoding or decoding device of Embodiment 1, replace the component corresponding to the component described in each aspect of the disclosure with the component described in each aspect of the disclosure, among the plurality of components constituting the encoding or decoding device. (2) With respect to the encoding or decoding device of Embodiment 1, any modifications such as adding, replacing, or deleting functions or processes performed by some of the multiple components constituting the encoding or decoding device are made, and then the components corresponding to the components described in each aspect of the Disclosure are replaced with the components described in each aspect of the Disclosure. (3) Adding processing to and / or replacing, deleting, or otherwise modifying some of the processing included in the method performed by the encoding or decoding device of Embodiment 1, and then replacing the processing corresponding to the processing described in each aspect of the Disclosure with the processing described in each aspect of the Disclosure. (4) Combining some of the multiple components constituting the encoding or decoding device of Embodiment 1 with a component described in each aspect of the Disclosure, a component that has some of the functions of the component described in each aspect of the Disclosure, or a component that performs some of the processing performed by the component described in each aspect of the Disclosure. (5) A component that has some of the functions of some of the components constituting the encoding or decoding device of Embodiment 1, or a component that performs some of the processing performed by some of the components constituting the encoding or decoding device of Embodiment 1, in combination with a component described in each aspect of this disclosure, a component that has some of the functions of the components described in each aspect of this disclosure, or a component that performs some of the processing performed by the components described in each aspect of this disclosure. (6) With respect to the method performed by the encoding or decoding device of Embodiment 1, replace with the process corresponding to the process described in each aspect of the Disclosure among the multiple processes included in the method with the process described in each aspect of the Disclosure. (7) Performing some of the processes included in the method performed by the encoding or decoding device of Embodiment 1 in combination with the processes described in each aspect of the present disclosure.

[0070] The methods of implementing the processes and / or configurations described in each aspect of this disclosure are not limited to the examples above. For example, they may be implemented in a device used for a purpose other than the video / image encoding device or video / image decoding device disclosed in Embodiment 1, or the processes and / or configurations described in each embodiment may be implemented individually. Furthermore, the processes and / or configurations described in different embodiments may be implemented in combination.

[0071] [Overview of the coding device] First, an overview of the encoding device according to Embodiment 1 will be described. Figure 1 is a block diagram showing the functional configuration of the encoding device 100 according to Embodiment 1. The encoding device 100 is a video / image encoding device that encodes video / images in block units.

[0072] As shown in Figure 1, the encoding device 100 is a device that encodes an image in block units and comprises a division unit 102, a subtraction unit 104, a transformation unit 106, a quantization unit 108, an entropy encoding unit 110, an inverse quantization unit 112, an inverse transformation unit 114, an addition unit 116, a block memory 118, a loop filter unit 120, a frame memory 122, an intra prediction unit 124, an inter prediction unit 126, and a prediction control unit 128.

[0073] The encoding device 100 can be implemented, for example, by a general-purpose processor and memory. In this case, when a software program stored in memory is executed by the processor, the processor functions as a splitting unit 102, a subtraction unit 104, a conversion unit 106, a quantization unit 108, an entropy encoding unit 110, an inverse quantization unit 112, an inverse conversion unit 114, an addition unit 116, a loop filter unit 120, an intra prediction unit 124, an inter prediction unit 126, and a prediction control unit 128. Alternatively, the encoding device 100 may be implemented as one or more dedicated electronic circuits corresponding to the splitting unit 102, a subtraction unit 104, a conversion unit 106, a quantization unit 108, an entropy encoding unit 110, an inverse quantization unit 112, an inverse conversion unit 114, an addition unit 116, a loop filter unit 120, an intra prediction unit 124, an inter prediction unit 126, and a prediction control unit 128.

[0074] The following describes each component included in the encoding device 100.

[0075] [Divided part] The splitting unit 102 divides each picture contained in the input video into multiple blocks and outputs each block to the subtraction unit 104. For example, the splitting unit 102 first divides the picture into blocks of a fixed size (e.g., 128x128). These fixed-size blocks are sometimes called coding tree units (CTUs). Then, based on recursive quadtree and / or binary tree block partitioning, the splitting unit 102 divides each of the fixed-size blocks into blocks of a variable size (e.g., 64x64 or less). These variable-size blocks are sometimes called coding units (CUs), prediction units (PUs), or transformation units (TUs). In this embodiment, CUs, PUs, and TUs do not need to be distinguished, and some or all of the blocks in the picture may become processing units for CUs, PUs, and TUs.

[0076] Figure 2 shows an example of block partitioning in Embodiment 1. In Figure 2, solid lines represent block boundaries due to quadtree block partitioning, and dashed lines represent block boundaries due to binary tree block partitioning.

[0077] Here, block 10 is a 128x128 pixel square block (128x128 block). This 128x128 block 10 is first divided into four 64x64 square blocks (quadtree block partitioning).

[0078] The top-left 64x64 block is further divided vertically into two rectangular 32x64 blocks, and the left 32x64 block is further divided vertically into two rectangular 16x64 blocks (binary tree block partitioning). As a result, the top-left 64x64 block is divided into two 16x64 blocks 11 and 12 and a 32x64 block 13.

[0079] The 64x64 block in the upper right is horizontally divided into two rectangular 64x32 blocks, 14 and 15 (binary tree block division).

[0080] The bottom-left 64x64 block is divided into four square 32x32 blocks (quadrutree block division). Of the four 32x32 blocks, the top-left and bottom-right blocks are further divided. The top-left 32x32 block is vertically divided into two rectangular 16x32 blocks, and the rightmost 16x32 block is further horizontally divided into two 16x16 blocks (binary tree block division). The bottom-right 32x32 block is horizontally divided into two 32x16 blocks (binary tree block division). As a result, the bottom-left 64x64 block is divided into 16x32 block 16, two 16x16 blocks 17 and 18, two 32x32 blocks 19 and 20, and two 32x16 blocks 21 and 22.

[0081] The 64x64 block 23 in the bottom right will not be divided.

[0082] As described above, in Figure 2, block 10 is divided into 13 variable-sized blocks 11-23 based on recursive quad-tree and binary tree block partitioning. Such partitioning is sometimes called QTBT (quad-tree plus binary tree) partitioning.

[0083] In Figure 2, one block was divided into four or two blocks (quadrutree or binary tree block partitioning), but the partitioning is not limited to these. For example, one block may be divided into three blocks (ternary tree block partitioning). Partitioning that includes such ternary tree block partitioning is sometimes called MBT (multi-type tree) partitioning.

[0084] [Subtraction Unit] The subtraction unit 104 subtracts the predicted signal (predicted sample) from the original signal (original sample) in block units divided by the division unit 102. In other words, the subtraction unit 104 calculates the prediction error (also called the residual) of the block to be encoded (hereinafter referred to as the current block). The subtraction unit 104 then outputs the calculated prediction error to the conversion unit 106.

[0085] The source signal is the input signal to the encoding device 100, and is a signal representing the image of each picture that makes up the moving image (for example, a luminance (luma) signal and two chroma (chroma) signals). In the following, the signal representing the image may also be called a sample.

[0086] [Conversion section] The conversion unit 106 converts the prediction error in the spatial domain into conversion coefficients in the frequency domain and outputs the conversion coefficients to the quantization unit 108. Specifically, the conversion unit 106 performs a predetermined discrete cosine transform (DCT) or discrete sine transform (DST) on the prediction error in the spatial domain, for example.

[0087] The transformation unit 106 may also adaptively select a transformation type from among several transformation types and use a transformation basis function corresponding to the selected transformation type to convert the prediction error into transformation coefficients. Such a transformation is sometimes called an EMT (explicit multiple core transform) or an AMT (adaptive multiple transform).

[0088] Multiple transformation types include, for example, DCT-II, DCT-V, DCT-VIII, DST-I, and DST-VII. Figure 3 is a table showing the transformation basis functions corresponding to each transformation type. In Figure 3, N represents the number of input pixels. The selection of a transformation type from among these multiple transformation types may depend, for example, on the type of prediction (intra-prediction and inter-prediction) or on the intra-prediction mode.

[0089] Information indicating whether or not to apply such EMT or AMT (e.g., called an AMT flag) and information indicating the selected conversion type are signaled at the CU level. However, the signaling of this information is not limited to the CU level and may be at other levels (e.g., sequence level, picture level, slice level, tile level, or CTU level).

[0090] Furthermore, the transformation unit 106 may retransform the transformation coefficients (transformation results). Such retransformation is sometimes called AST (adaptive secondary transform) or NSST (non-separable secondary transform). For example, the transformation unit 106 performs retransformation for each subblock (e.g., 4x4 subblock) contained in the block of transformation coefficients corresponding to the intra-prediction error. Information indicating whether or not to apply NSST and information regarding the transformation matrix used for NSST are signaled at the CU level. Note that the signaling of this information is not limited to the CU level, but may be at other levels (e.g., sequence level, picture level, slice level, tile level, or CTU level).

[0091] Here, a separable transformation is a method in which the input is separated into directions equal to the number of dimensions and transformed multiple times, while a non-separable transformation is a method in which, when the input is multidimensional, two or more dimensions are treated as one dimension and transformed together.

[0092] For example, one example of a non-separable transformation is to treat a 4x4 block as a single array with 16 elements and then perform a transformation on that array using a 16x16 transformation matrix.

[0093] Similarly, the Hypercube Givens Transform, which treats a 4x4 input block as a single array with 16 elements and then performs multiple Givens rotations on that array, is another example of a non-separable transformation.

[0094] [Quantization section] The quantization unit 108 quantizes the conversion coefficients output from the conversion unit 106. Specifically, the quantization unit 108 scans the conversion coefficients of the current block in a predetermined scanning order and quantizes the conversion coefficients based on the quantization parameter (QP) corresponding to the scanned conversion coefficients. The quantization unit 108 then outputs the quantized conversion coefficients of the current block (hereinafter referred to as quantization coefficients) to the entropy coding unit 110 and the inverse quantization unit 112.

[0095] The predetermined order is the order for quantization / inverse quantization of the transformation coefficients. For example, the predetermined scanning order is defined as ascending frequency (from low frequency to high frequency) or descending frequency (from high frequency to low frequency).

[0096] Quantization parameters are parameters that define the quantization step (quantization width). For example, if the value of the quantization parameter increases, the quantization step also increases. In other words, if the value of the quantization parameter increases, the quantization error increases.

[0097] [Entropy coding unit] The entropy coding unit 110 generates an encoded signal (encoded bitstream) by variable-length encoding the quantization coefficients, which are input from the quantization unit 108. Specifically, the entropy coding unit 110, for example, binarizes the quantization coefficients and arithmetically encodes the binary signal.

[0098] [Dequantization section] The inverse quantization unit 112 inversely quantizes the quantization coefficients, which are input from the quantization unit 108. Specifically, the inverse quantization unit 112 inversely quantizes the quantization coefficients of the current block in a predetermined scanning order. Then, the inverse quantization unit 112 outputs the inversely quantized conversion coefficients of the current block to the inverse conversion unit 114.

[0099] [Inverse Transformation Section] The inverse transform unit 114 restores the prediction error by inversely transforming the transformation coefficients, which are input from the inverse quantization unit 112. Specifically, the inverse transform unit 114 restores the prediction error of the current block by performing an inverse transform on the transformation coefficients that corresponds to the transformation by the transformation unit 106. The inverse transform unit 114 then outputs the restored prediction error to the summation unit 116.

[0100] Furthermore, the recovered prediction error does not match the prediction error calculated by the subtraction unit 104 because information is lost due to quantization. In other words, the recovered prediction error includes quantization errors.

[0101] [Addition section] The adder 116 reconstructs the current block by adding the prediction error, which is the input from the inverse transformer 114, and the prediction sample, which is the input from the prediction control unit 128. The adder 116 then outputs the reconstructed block to the block memory 118 and the loop filter unit 120. The reconstructed block is sometimes called the local decoded block.

[0102] [Block memory] The block memory 118 is a storage unit for storing blocks within the picture to be encoded (hereinafter referred to as the current picture) that are referenced in intra prediction. Specifically, the block memory 118 stores the reconstructed blocks output from the adder 116.

[0103] [Loop Filter Section] The loop filter unit 120 applies a loop filter to the block reconstructed by the adder unit 116 and outputs the filtered reconstructed block to the frame memory 122. A loop filter is a filter used within the encoding loop (in-loop filter), and includes, for example, a deblocking filter (DF), sample adaptive offset (SAO), and adaptive loop filter (ALF).

[0104] In ALF, a least-squares error filter is applied to remove coding distortion. For example, for each 2x2 subblock within the current block, one filter selected from several filters is applied based on the direction and activity of the local gradient.

[0105] Specifically, first, subblocks (e.g., 2x2 subblocks) are classified into multiple classes (e.g., 15 or 25 classes). The classification of subblocks is based on the direction and activity of the gradient. For example, a classification value C (e.g., C = 5D + A) is calculated using the gradient direction value D (e.g., 0-2 or 0-4) and the gradient activity value A (e.g., 0-4). Then, based on the classification value C, the subblocks are classified into multiple classes (e.g., 15 or 25 classes).

[0106] The gradient direction value D is derived, for example, by comparing gradients in multiple directions (e.g., horizontal, vertical, and two diagonal directions). The gradient activation value A is derived, for example, by adding the gradients in multiple directions and quantizing the sum.

[0107] Based on the results of this classification, a filter for the subblock is determined from among multiple filters.

[0108] For example, a circularly symmetric shape is used as the filter shape in ALF. Figures 4A to 4C show several examples of filter shapes used in ALF. Figure 4A shows a 5x5 diamond-shaped filter, Figure 4B shows a 7x7 diamond-shaped filter, and Figure 4C shows a 9x9 diamond-shaped filter. Information indicating the filter shape is signaled at the picture level. However, the signaling of information indicating the filter shape is not limited to the picture level and may be at other levels (e.g., sequence level, slice level, tile level, CTU level, or CU level).

[0109] The on / off status of ALF is determined, for example, at the picture level or CU level. For instance, the decision to apply ALF to luminance is made at the CU level, and the decision to apply ALF to color difference is made at the picture level. Information indicating whether ALF is on or off is signaled at the picture level or CU level. However, the signaling of information indicating whether ALF is on or off is not limited to the picture level or CU level, but may be at other levels (e.g., sequence level, slice level, tile level, or CTU level).

[0110] The coefficient sets of multiple selectable filters (e.g., up to 15 or 25 filters) are signaled at the picture level. However, the signaling of the coefficient sets is not limited to the picture level; it may be at other levels (e.g., sequence level, slice level, tile level, CTU level, CU level, or subblock level).

[0111] [Frame memory] The frame memory 122 is a storage unit for storing reference pictures used for interpretation, and is sometimes called a frame buffer. Specifically, the frame memory 122 stores the reconstructed blocks filtered by the loop filter unit 120.

[0112] [Intra Prediction Unit] The intra-prediction unit 124 generates a prediction signal (intra-prediction signal) by performing intra-prediction (also called in-screen prediction) of the current block by referring to the block in the current picture stored in the block memory 118. Specifically, the intra-prediction unit 124 generates an intra-prediction signal by performing intra-prediction by referring to samples (e.g., luminance values, color difference values) of blocks adjacent to the current block, and outputs the intra-prediction signal to the prediction control unit 128.

[0113] For example, the intra-prediction unit 124 performs intra-prediction using one of a predetermined set of intra-prediction modes. The set of intra-prediction modes includes one or more non-directional prediction modes and multiple directional prediction modes.

[0114] One or more non-directional prediction modes include, for example, the Planar prediction mode and DC prediction mode as defined in the H.265 / HEVC (High-Efficiency Video Coding) standard (Non-Patent Document 1).

[0115] Multiple directional prediction modes include, for example, the 33 directional prediction modes defined in the H.265 / HEVC standard. Note that multiple directional prediction modes may also include 32 additional directional prediction modes (a total of 65 directional prediction modes). Figure 5A shows 67 intra-prediction modes (2 non-directional prediction modes and 65 directional prediction modes) in intra-prediction. Solid arrows represent the 33 directions defined in the H.265 / HEVC standard, and dashed arrows represent the additional 32 directions.

[0116] Furthermore, in the intra-prediction of a color difference block, a luminance block may be referenced. That is, the color difference component of the current block may be predicted based on the luminance component of the current block. Such intra-prediction is sometimes called CCLM (cross-component linear model) prediction. Such an intra-prediction mode for a color difference block that references a luminance block (e.g., called the CCLM mode) may be added as one of the intra-prediction modes for a color difference block.

[0117] The intra-prediction unit 124 may correct the pixel values ​​after intra-prediction based on the gradient of the horizontal / vertical reference pixels. Intra-prediction with such correction is sometimes called PDPC (position dependent intra-prediction combination). Information indicating whether or not PDPC is applied (for example, called a PDPC flag) is signaled at, for example, the CU level. Note that the signaling of this information is not limited to the CU level, but may be at other levels (for example, sequence level, picture level, slice level, tile level, or CTU level).

[0118] [International Prediction Department] The inter-prediction unit 126 generates a prediction signal (inter-prediction signal) by performing inter-prediction (also called inter-screen prediction) of the current block by referring to a reference picture stored in the frame memory 122 that is different from the current picture. Inter-prediction is performed in units of the current block or sub-blocks within the current block (e.g., 4x4 blocks). For example, the inter-prediction unit 126 performs motion estimation within the reference picture for the current block or sub-block. Then, the inter-prediction unit 126 generates an inter-prediction signal for the current block or sub-block by performing motion compensation using motion information (e.g., motion vectors) obtained from the motion estimation. Finally, the inter-prediction unit 126 outputs the generated inter-prediction signal to the prediction control unit 128.

[0119] The motion information used for motion compensation is converted into a signal. A motion vector predictor may be used to convert the motion vector into a signal. In other words, the difference between the motion vector and the predicted motion vector may be converted into a signal.

[0120] Furthermore, an inter-prediction signal may be generated using not only the motion information of the current block obtained through motion search, but also the motion information of adjacent blocks. Specifically, an inter-prediction signal may be generated for each sub-block within the current block by weighted addition of a prediction signal based on motion information obtained through motion search and a prediction signal based on the motion information of adjacent blocks. Such inter-prediction (motion compensation) is sometimes called OBMC (overlapped block motion compensation).

[0121] In this OBMC mode, information indicating the size of the subblock for OBMC (e.g., called the OBMC block size) is signaled at the sequence level. Information indicating whether or not to apply OBMC mode (e.g., called the OBMC flag) is signaled at the CU level. Note that the signaling levels for this information are not limited to the sequence and CU levels; other levels (e.g., picture level, slice level, tile level, CTU level, or subblock level) may also be used.

[0122] Let's explain the OBMC mode in more detail. Figures 5B and 5C are flowcharts and conceptual diagrams illustrating the overview of the predictive image correction process using OBMC processing.

[0123] First, a predicted image (Pred) is obtained using normal motion compensation with the motion vector (MV) assigned to the block to be encoded.

[0124] Next, the motion vector (MV_L) of the encoded left adjacent block is applied to the block to be encoded to obtain a predicted image (Pred_L), and the first correction of the predicted image is performed by superimposing the predicted image and Pred_L with weights.

[0125] Similarly, the motion vector (MV_U) of the encoded upper adjacent block is applied to the block to be encoded to obtain a predicted image (Pred_U). The predicted image is then corrected a second time by weighting the first corrected predicted image and Pred_U, and this is used as the final predicted image.

[0126] While this explanation describes a two-stage correction method using the left adjacent block and the upper adjacent block, it is also possible to configure the system to perform more corrections than two stages using the right adjacent block and the lower adjacent block.

[0127] Furthermore, the area to be superimposed does not have to be the entire pixel area of ​​the block, but rather only a portion of the area near the block boundary.

[0128] Although this explanation describes the predictive image correction process using a single reference picture, the process is similar when correcting predictive images from multiple reference pictures. After obtaining corrected predictive images from each reference picture, the resulting predictive images are superimposed to create the final predictive image.

[0129] The processing target block may be a prediction block unit, or it may be a sub-block unit obtained by further dividing the prediction block.

[0130] One method for determining whether or not to apply OBMC processing is to use an obmc_flag signal, which indicates whether or not to apply OBMC processing. Specifically, in an encoding device, it is determined whether or not the block to be encoded belongs to a region with complex motion. If it belongs to a region with complex motion, the obmc_flag is set to a value of 1 and OBMC processing is applied to perform encoding. If it does not belong to a region with complex motion, the obmc_flag is set to a value of 0 and encoding is performed without applying OBMC processing. On the other hand, in a decoding device, the obmc_flag written in the stream is decoded, and the device switches whether or not to apply OBMC processing depending on its value and performs decoding.

[0131] Furthermore, motion information may be derived by the decoder without being converted into a signal. For example, the merge mode specified in the H.265 / HEVC standard may be used. Alternatively, motion information may be derived by performing a motion search on the decoder side. In this case, the motion search is performed without using the pixel values ​​of the current block.

[0132] Here, we will explain the mode in which motion detection is performed on the decoding device side. This mode in which motion detection is performed on the decoding device side is sometimes called PMMVD (pattern matched motion vector derivation) mode or FRUC (frame rate up-conversion) mode.

[0133] An example of FRUC processing is shown in Figure 5D. First, a list of multiple candidates (which may be the same as the merge list) is generated, each having a predicted motion vector, by referencing the motion vectors of spatially or temporally adjacent encoded blocks to the current block. Next, the best candidate MV is selected from among the multiple candidate MVs registered in the candidate list. For example, an evaluation value is calculated for each candidate included in the candidate list, and one candidate is selected based on the evaluation value.

[0134] Then, based on the motion vectors of the selected candidates, a motion vector for the current block is derived. Specifically, for example, the motion vector of the selected candidate (best candidate MV) is directly derived as the motion vector for the current block. Alternatively, for example, the motion vector for the current block may be derived by performing pattern matching in the area surrounding the position in the reference picture corresponding to the motion vector of the selected candidate. That is, a similar search is performed in the area surrounding the best candidate MV, and if an MV with a better evaluation value is found, the best candidate MV may be updated to this MV and used as the final MV for the current block. It is also possible to configure the system so that this process is not performed.

[0135] The same processing method can be used when processing at the sub-block level.

[0136] The evaluation value is calculated by determining the difference value of the reconstructed image through pattern matching between a region in the reference picture corresponding to the motion vector and a predetermined region. Alternatively, the evaluation value may be calculated using information other than the difference value.

[0137] For pattern matching, either first-order pattern matching or second-order pattern matching is used. First-order pattern matching and second-order pattern matching are sometimes called bilateral matching and template matching, respectively.

[0138] In the first pattern matching, pattern matching is performed between two blocks in two different reference pictures that are aligned with the motion trajectory of the current block. Therefore, in the first pattern matching, a region in another reference picture aligned with the motion trajectory of the current block is used as a predetermined region for calculating the evaluation value of the candidate described above.

[0139] Figure 6 illustrates an example of pattern matching (bilateral matching) between two blocks along a motion trajectory. As shown in Figure 6, in the first pattern matching, two motion vectors (MV0, MV1) are derived by searching for the best-matching pair of two blocks within two different reference pictures (Ref0, Ref1) that are along the motion trajectory of the current block. Specifically, for the current block, the difference between the reconstructed image at a specified position in the first encoded reference picture (Ref0) specified by the candidate MV and the reconstructed image at a specified position in the second encoded reference picture (Ref1) specified by the symmetric MV obtained by scaling the candidate MV by the display time interval is derived, and an evaluation value is calculated using the obtained difference value. It is preferable to select the candidate MV with the best evaluation value among multiple candidate MVs as the final MV.

[0140] Under the assumption of a continuous motion trajectory, the motion vector (MV0, MV1) pointing to two reference blocks is proportional to the temporal distance (TD0, TD1) between the current picture (Cur Pic) and the two reference pictures (Ref0, Ref1). For example, if the current picture is temporally located between the two reference pictures and the temporal distances from the current picture to the two reference pictures are equal, then the first pattern matching derives a mirror-symmetric bidirectional motion vector.

[0141] In the second pattern matching, pattern matching is performed between the template in the current picture (blocks adjacent to the current block in the current picture (e.g., blocks above and / or to the left)) and the blocks in the reference picture. Therefore, in the second pattern matching, the blocks adjacent to the current block in the current picture are used as a predetermined area for calculating the evaluation value of the candidates mentioned above.

[0142] Figure 7 illustrates an example of pattern matching (template matching) between a template in the current picture and a block in the reference picture. As shown in Figure 7, in the second pattern matching, the motion vector of the current block is derived by searching in the reference picture (Ref0) for the block that best matches the block adjacent to the current block (Cur block) in the current picture (Cur Pic). Specifically, for the current block, the difference is derived between the reconstructed image of the encoded region of both or either of the left adjacent and upper adjacent regions and the reconstructed image at the equivalent position in the encoded reference picture (Ref0) specified by the candidate MV. An evaluation value is calculated using the obtained difference value, and the candidate MV with the best evaluation value among multiple candidate MVs is selected as the best candidate MV.

[0143] Information indicating whether or not to apply such a FRUC mode (e.g., called the FRUC flag) is signaled at the CU level. Furthermore, if the FRUC mode is applied (e.g., the FRUC flag is true), information indicating the pattern matching method (first pattern matching or second pattern matching) (e.g., called the FRUC mode flag) is signaled at the CU level. Note that the signaling of this information is not limited to the CU level; it may be at other levels (e.g., sequence level, picture level, slice level, tile level, CTU level, or subblock level).

[0144] Here, we will describe a mode for deriving motion vectors based on a model that assumes uniform linear motion. This mode is sometimes called the BIO (bi-directional optical flow) mode.

[0145] Figure 8 is a diagram illustrating a model that assumes uniform linear motion. In Figure 8, (v x ,v y) represents a velocity vector, and τ0 and τ1 respectively represent temporal distances between the current picture (Cur Pic) and the two reference pictures (Ref0, Ref1). (MVx0, MVy0) represents a motion vector corresponding to reference picture Ref0, and (MVx1, MVy1) represents a motion vector corresponding to reference picture Ref1.

[0146] At this time, the velocity vector v x , v y ), under the assumption of uniform linear motion, (MVx0, MVy0) and (MVx1, MVy1) are respectively (v x τ0, v y τ0) and (-v x τ1, -v y τ1), and the following optical flow equation (1) holds.

[0147]

Math

[0148] Here, I (k) represents a luminance value of reference image k (k=0,1) after motion compensation. This optical flow equation indicates that the sum of (i) the time derivative of the luminance value, (ii) the product of the horizontal velocity and the horizontal component of the spatial gradient of the reference image, and (iii) the product of the vertical velocity and the vertical component of the spatial gradient of the reference image is equal to zero. Based on the combination of this optical flow equation and Hermite interpolation, block-level motion vectors obtained from a merge list or the like are corrected in pixel units.

[0149] Note that the motion vectors may be derived at the decoding device side by a method different from the method of deriving motion vectors based on a model assuming uniform linear motion. For example, motion vectors may be derived in subblock units based on motion vectors of a plurality of adjacent blocks.

[0150] Here, we will describe a mode in which motion vectors are derived at the sub-block level based on the motion vectors of multiple adjacent blocks. This mode is sometimes called the affine motion compensation prediction mode.

[0151] Figure 9A is a diagram illustrating the derivation of subblock-level motion vectors based on the motion vectors of multiple adjacent blocks. In Figure 9A, the current block contains 16 4x4 subblocks. Here, the motion vector v0 of the upper left corner control point of the current block is derived based on the motion vectors of the adjacent blocks, and the motion vector v1 of the upper right corner control point of the current block is derived based on the motion vectors of the adjacent subblocks. Then, using the two motion vectors v0 and v1, the motion vector (v) of each subblock within the current block is derived by the following equation (2). x ,v y ) is derived.

[0152]

number

[0153] Here, x and y represent the horizontal and vertical positions of the subblock, respectively, and w represents a predetermined weighting coefficient.

[0154] Such affine motion compensation prediction modes may include several modes in which the motion vectors of the upper-left and upper-right corner control points are derived. Information indicating such affine motion compensation prediction modes (e.g., called affine flags) is signaled at the CU level. Note that the signaling of this information indicating affine motion compensation prediction modes is not limited to the CU level, but may be at other levels (e.g., sequence level, picture level, slice level, tile level, CTU level, or subblock level).

[0155] [Prediction Control Unit] The prediction control unit 128 selects either the intra-prediction signal or the inter-prediction signal and outputs the selected signal as the prediction signal to the subtraction unit 104 and the addition unit 116.

[0156] Here, we will explain an example of deriving the motion vector of a picture to be encoded using merge mode. Figure 9B is a diagram illustrating the overview of the motion vector derivation process using merge mode.

[0157] First, a list of predicted MVs is generated, containing registered candidates for predicted MVs. Candidates for predicted MVs include spatially adjacent predicted MVs, which are the MVs of multiple encoded blocks located spatially around the block to be encoded; temporally adjacent predicted MVs, which are the MVs of nearby blocks projected onto the location of the block to be encoded in the encoded reference picture; combined predicted MVs, which are generated by combining the MV values ​​of spatially adjacent predicted MVs and temporally adjacent predicted MVs; and zero predicted MVs, which are MVs with a value of zero.

[0158] Next, one predicted MV is selected from the multiple predicted MVs registered in the predicted MV list to determine it as the MV for the block to be encoded.

[0159] Furthermore, the variable-length coding unit encodes the merge_idx signal, which indicates which predicted MV was selected, by writing it to a stream.

[0160] Note that the predicted MVs registered in the predicted MV list explained in Figure 9B are just an example, and the number of predicted MVs may differ from the number shown in the figure, the configuration may not include some of the types of predicted MVs shown in the figure, or it may include predicted MVs other than those shown in the figure.

[0161] Alternatively, the final MV may be determined by performing the DMVR process described later using the MV of the target block to be encoded derived by merge mode.

[0162] Here, we will explain an example of determining the MV using DMVR processing.

[0163] Figure 9C is a conceptual diagram illustrating the overview of DMVR processing.

[0164] First, the optimal MVP set for the block to be processed is used as a candidate MV. According to the candidate MV, reference pixels are obtained from the first reference picture, which is a processed picture in the L0 direction, and the second reference picture, which is a processed picture in the L1 direction, and a template is generated by taking the average of each reference pixel.

[0165] Next, using the template, the surrounding regions of candidate MVs for the first and second reference pictures are searched, and the MV with the lowest cost is determined as the final MV. The cost value is calculated using the difference between each pixel value of the template and each pixel value of the search region, as well as the MV value, etc.

[0166] Note that the general outline of the processing described here is basically the same for both the encoding and decoding devices.

[0167] Note that any process that can explore the vicinity of a candidate MV and derive the final MV may be used instead of the exact process described here.

[0168] Here, we will explain the mode for generating predictive images using LIC processing.

[0169] Figure 9D is a diagram illustrating the outline of a predictive image generation method using luminance correction processing by LIC processing.

[0170] First, we derive a Music Model (MV) to obtain the reference image corresponding to the block to be encoded from the reference picture, which is an already encoded picture.

[0171] Next, for the block to be encoded, information indicating how the luminance values ​​have changed between the reference picture and the picture to be encoded is extracted using the luminance pixel values ​​of the left-adjacent and top-adjacent encoded surrounding reference regions, and the luminance pixel values ​​at the equivalent positions in the reference picture specified by MV, and a luminance correction parameter is calculated.

[0172] By performing brightness correction processing on the reference image within the reference picture specified in MV using the brightness correction parameter, a predicted image for the encoding target block is generated.

[0173] Note that the shape of the surrounding reference region in Figure 9D is just one example, and other shapes may be used.

[0174] Furthermore, while this explanation describes the process of generating a predicted image from a single reference picture, the process is similar when generating predicted images from multiple reference pictures. Brightness correction processing is performed on each reference image obtained from a single reference picture in the same manner before generating the predicted image.

[0175] One method for determining whether or not to apply LIC processing is to use a signal called lic_flag, which indicates whether or not to apply LIC processing. Specifically, in an encoding device, it is determined whether or not the block to be encoded belongs to a region where brightness changes occur. If it belongs to a region where brightness changes occur, the value of lic_flag is set to 1 and LIC processing is applied and encoding is performed. If it does not belong to a region where brightness changes occur, the value of lic_flag is set to 0 and encoding is performed without applying LIC processing. On the other hand, in a decoding device, the lic_flag written in the stream is decoded, and the device switches whether or not to apply LIC processing according to its value and performs decoding.

[0176] Another way to determine whether to apply LIC processing is, for example, by checking whether LIC processing has been applied to surrounding blocks. A specific example is that if the block to be encoded is in merge mode, during the MV derivation in merge mode processing, it is determined whether the surrounding encoded blocks selected were encoded with LIC processing. Based on this result, the application of LIC processing is switched, and encoding is performed accordingly. In this example, the decoding process is exactly the same.

[0177] [Overview of the decryption device] Next, an overview of a decoding device capable of decoding the encoded signal (encoded bitstream) output from the above-mentioned encoding device 100 will be described. Figure 10 is a block diagram showing the functional configuration of the decoding device 200 according to Embodiment 1. The decoding device 200 is a video / image decoding device that decodes video / images in block units.

[0178] As shown in Figure 10, the decoding device 200 includes an entropy decoding unit 202, an inverse quantization unit 204, an inverse transform unit 206, an adder unit 208, a block memory 210, a loop filter unit 212, a frame memory 214, an intra prediction unit 216, an inter prediction unit 218, and a prediction control unit 220.

[0179] The decoding device 200 can be implemented, for example, by a general-purpose processor and memory. In this case, when the software program stored in memory is executed by the processor, the processor functions as an entropy decoding unit 202, an inverse quantization unit 204, an inverse transformation unit 206, an addition unit 208, a loop filter unit 212, an intra prediction unit 216, an inter prediction unit 218, and a prediction control unit 220. Alternatively, the decoding device 200 may be implemented as one or more dedicated electronic circuits corresponding to the entropy decoding unit 202, the inverse quantization unit 204, the inverse transformation unit 206, the addition unit 208, the loop filter unit 212, the intra prediction unit 216, the inter prediction unit 218, and the prediction control unit 220.

[0180] The following describes each component included in the decoding device 200.

[0181] [Entropy Decoder] The entropy decoding unit 202 entropically decodes the encoded bitstream. Specifically, the entropy decoding unit 202 arithmetically decodes the encoded bitstream into a binary signal, for example. Then, the entropy decoding unit 202 debinarizes the binary signal. As a result, the entropy decoding unit 202 outputs the quantization coefficients in block units to the inverse quantization unit 204.

[0182] [Dequantization section] The inverse quantization unit 204 inversely quantizes the quantization coefficients of the decoded block (hereinafter referred to as the current block), which is the input from the entropy decoding unit 202. Specifically, for each quantization coefficient of the current block, the inverse quantization unit 204 inversely quantizes the quantization coefficient based on the quantization parameter corresponding to that quantization coefficient. The inverse quantization unit 204 then outputs the inversely quantized quantization coefficients (i.e., transformation coefficients) of the current block to the inverse transformation unit 206.

[0183] [Inverse Transformation Section] The inverse transform unit 206 restores the prediction error by inversely transforming the transformation coefficients, which are input from the inverse quantization unit 204.

[0184] For example, if the information decoded from the encoded bitstream indicates that EMT or AMT should be applied (e.g., the AMT flag is true), the inverse transform unit 206 inversely transforms the transformation coefficients of the current block based on the information indicating the decoded transformation type.

[0185] For example, if the information decoded from the encoded bitstream indicates that NSST should be applied, the inverse transform unit 206 applies inverse retransformation to the transformation coefficients.

[0186] [Addition section] The adder 208 reconstructs the current block by adding the prediction error, which is the input from the inverse transformer 206, and the prediction sample, which is the input from the prediction control unit 220. The adder 208 then outputs the reconstructed block to the block memory 210 and the loop filter unit 212.

[0187] [Block memory] The block memory 210 is a storage unit for storing blocks that are referenced in intra prediction and are located within the decoded picture (hereinafter referred to as the current picture). Specifically, the block memory 210 stores the reconstructed blocks output from the adder 208.

[0188] [Loop Filter Section] The loop filter unit 212 applies a loop filter to the block reconstructed by the adder unit 208 and outputs the filtered reconstructed block to the frame memory 214 and the display device, etc.

[0189] If the information interpreted from the encoded bitstream indicating ALF on / off indicates ALF is on, one filter is selected from among several filters based on the direction and activity of the local gradient, and the selected filter is applied to the reconstruction block.

[0190] [Frame memory] The frame memory 214 is a memory unit for storing reference pictures used for interpretation, and is sometimes called a frame buffer. Specifically, the frame memory 214 stores the reconstructed blocks filtered by the loop filter unit 212.

[0191] [Intra Prediction Unit] The intra-prediction unit 216 generates a prediction signal (intra-prediction signal) by performing intra-prediction based on the intra-prediction mode decoded from the encoded bitstream, and by referring to the blocks in the current picture stored in the block memory 210. Specifically, the intra-prediction unit 216 generates an intra-prediction signal by performing intra-prediction by referring to samples (e.g., luminance values, chrominance values) of blocks adjacent to the current block, and outputs the intra-prediction signal to the prediction control unit 220.

[0192] Furthermore, if an intra-prediction mode that references a luminance block is selected in the intra-prediction of a color difference block, the intra-prediction unit 216 may predict the color difference component of the current block based on the luminance component of the current block.

[0193] Furthermore, if the information decoded from the encoded bitstream indicates the application of PDPC, the intra-prediction unit 216 corrects the pixel value after intra-prediction based on the gradient of the reference pixels in the horizontal / vertical directions.

[0194] [International Prediction Department] The inter-prediction unit 218 predicts the current block by referring to a reference picture stored in the frame memory 214. Prediction is performed in units of the current block or sub-blocks within the current block (e.g., 4x4 blocks). For example, the inter-prediction unit 218 generates an inter-prediction signal for the current block or sub-block by performing motion compensation using motion information (e.g., motion vectors) decoded from the encoded bitstream, and outputs the inter-prediction signal to the prediction control unit 220.

[0195] Furthermore, if the information decoded from the encoded bitstream indicates that OBMC mode should be applied, the interpretation unit 218 generates an interpretation prediction signal using not only the motion information of the current block obtained by motion search, but also the motion information of adjacent blocks.

[0196] Furthermore, if the information decoded from the encoded bitstream indicates that FRUC mode should be applied, the interpretation unit 218 derives motion information by performing a motion search according to the pattern matching method (bilateral matching or template matching) decoded from the encoded stream. Then, the interpretation unit 218 performs motion compensation using the derived motion information.

[0197] Furthermore, when the BIO mode is applied, the inter-prediction unit 218 derives motion vectors based on a model that assumes uniform linear motion. Also, if the information decoded from the encoded bitstream indicates that the affine motion compensation prediction mode should be applied, the inter-prediction unit 218 derives motion vectors on a sub-block basis based on the motion vectors of multiple adjacent blocks.

[0198] [Prediction Control Unit] The prediction control unit 220 selects either the intra-prediction signal or the inter-prediction signal and outputs the selected signal as the prediction signal to the adder 208.

[0199] [First example of interpretation processing] Figure 11 shows a schematic first example of the pipeline configuration used in the decoding device 200. This pipeline configuration includes four stages: the first stage, the second stage, the third stage, and the fourth stage.

[0200] In the first stage, the decoding device 200 obtains the information necessary for decoding by performing entropy decoding on the input stream to be decoded (S101).

[0201] In the second stage, the decoding device 200 uses the aforementioned information to derive motion vectors (MVs) in the interpretation process. Specifically, the decoding device 200 first refers to the surrounding decoded blocks and derives one or more predicted motion vectors (hereinafter referred to as MVPs), which are candidates for motion vectors (S102). Next, the decoding device 200 performs memory transfer of the reference image according to the derived MVPs (S103).

[0202] Next, if the inter-prediction mode is FRUC mode, the decoder 200 determines the motion vector by performing optimal MVP determination (S104) and optimal MVP surrounding search (S105). If the inter-prediction mode is merge mode, the decoder 200 determines the motion vector by performing DMVR processing (S106).

[0203] In the third stage, the decoding device 200 decodes the residual image by inverse quantization and inverse transform processing (S110). If the target block is an intrablock, the decoding device 200 decodes the predicted image by intraprediction processing (S108). If the target block is an interblock, the decoding device 200 decodes the predicted image by performing motion compensation processing etc. using the motion vector derived in the second stage (S107).

[0204] Next, the decoding device 200 selects either the predicted image generated by the intra-prediction process or the predicted image generated by the inter-prediction process (S109), and generates a reconstructed image by adding the residual image and the selected predicted image (S111).

[0205] In the fourth stage, the decoding device 200 generates a decoded image by performing loop filtering on the reconstructed image (112).

[0206] The motion vectors derived in the second stage are used as peripheral reference motion vectors to derive the MVP in the decoding process of subsequent blocks, and are therefore fed back as input to the MVP derivation process (S102). In order to reference the motion vectors belonging to the immediately preceding block in the processing order, this feedback process must be contained within a single stage. As a result, as shown in Figure 11, the second stage consists of a very large number of processes, resulting in a long processing time.

[0207] Note that this pipeline configuration is just an example, and you may remove some of the processes described, add processes that are not listed, or change the way the stages are divided.

[0208] Figure 12 is a schematic diagram showing an example of block partitioning used to explain pipeline processing. The block partitioning example shown in Figure 12 shows two coding tree units. One coding tree unit contains two coding units CU0 and CU1, and the other coding tree unit contains three coding units CU2, CU3 and CU4.

[0209] Encoding units CU0, CU1, and CU4 are the same size. Encoding units CU2 and CU3 are the same size. The size of each encoding unit CU0, CU1, and CU4 is twice the size of each encoding unit CU2 and CU3.

[0210] Figure 13 is a time sequence showing the processing timing of each decryption target block's stage processing in the first example of the pipeline configuration outlined in Figure 11. Figure 13 shows the processing timing of the five decryption target blocks from encoding units CU0 to CU4 shown in Figure 12. Also, S1 to S4 in Figure 13 represent the processing times of the first to fourth stages in Figure 11.

[0211] Since encoding units CU0, CU1, and CU4 are twice as large as encoding units CU2 and CU3, the processing time for each stage is also twice as long.

[0212] Furthermore, as explained in Figure 11, the second stage has a long processing time, so the processing time for the second stage is twice as long as that of the other stages.

[0213] Each stage of processing begins only after waiting for the corresponding stage of the preceding block to finish in processing order. For example, the second stage of encoding unit CU1 starts at time t6, when the second stage of encoding unit CU0 has finished. In this case, since the processing time of the second stage of encoding unit CU0 is twice as long, encoding unit CU1 experiences a waiting period from time t4, when the first stage of processing finishes, until time t6, when the second stage of processing begins.

[0214] Thus, a waiting time always occurs at the start of the second stage, and this waiting time accumulates as the processing of the block to be decoded progresses. As a result, the encoding unit CU4 experiences a waiting time from time t8, when the processing of the first stage is completed, until time t14, when the processing of the second stage is revealed.

[0215] As a result, by the time the decryption process for one picture is complete, the total processing time, including waiting time, increases to approximately twice the original processing time. This can make it difficult to complete the processing of all blocks within the processing time allocated to one picture.

[0216] Figure 14 is a flowchart of the inter-prediction process in the first example of the pipeline configuration outlined in Figure 11. The process shown in Figure 14 is repeated in units of prediction blocks, which are the processing units of inter-screen prediction. The process shown in Figure 14 is performed in the encoding device 100 and the decoding device 200. In the following, the operation of the inter-prediction unit 126 included in the encoding device 100 will be mainly described, but the operation of the inter-prediction unit 218 included in the decoding device 200 is similar.

[0217] The interpretation unit 126 selects an interpretation mode from multiple modes (normal interpretation mode, merge mode, FRUC mode, etc.) to be used for the target block, which is the block to be encoded or decoded. The interpretation unit 126 derives a motion vector (MV) using the selected interpretation mode. Specifically, the interpretation mode information indicates the interpretation mode to be used for the target block.

[0218] When normal intermode is used (normal intermode in S201), the interpretation unit 126 obtains multiple predicted motion vectors (MVPs) by referring to the motion vectors of the surrounding processed blocks and creates a normal MVP list showing the multiple MVPs obtained. The interpretation unit 126 selects one MVP from the multiple MVPs shown in the created normal MVP list and determines the final motion vector by adding the difference motion vector (MVD) to the selected MVP (S202). Specifically, the encoding device 100 generates a difference motion vector from the motion vector and the MVP and transmits the generated difference motion vector to the decoding device 200. The decoding device 200 obtains the motion vector by adding the transmitted difference motion vector to the predicted motion vector.

[0219] When merge mode is used (merge mode in S201), the interpretation unit 126 obtains one or more MVPs by referring to the motion vectors of the surrounding processed blocks and creates a merge MVP list showing the one or more obtained MVPs. Next, the interpretation unit 126 designates one MVP from the created merge mode MVP list as the optimal MVP (S203). Next, the interpretation unit 126 determines the final motion vector by performing DMVR processing to search for the position with the minimum cost value in the surrounding area of ​​the optimal MVP using the processed picture (S204).

[0220] When FRUC mode is used (FRUC in S201), the interpretation unit 126 obtains multiple MVPs by referring to the motion vectors of the surrounding processed blocks and creates an MVP list for FRUC showing the multiple MVPs obtained (S205). Next, the interpretation unit 126 uses a bilateral matching method or a template matching method to derive the optimal MVP with the minimum cost value from among the multiple MVPs shown in the MVP list for FRUC (S206). Next, the interpretation unit 126 searches for the position with the minimum cost in the surrounding area of ​​the derived optimal MVP using the same process, and determines the motion vector obtained by the search as the final motion vector (S207).

[0221] The final motion vectors derived using each method are stored in peripheral reference MV memory because they are used as peripheral reference MVs for deriving the MVP of subsequent blocks.

[0222] Finally, the interpretation unit 126 generates a predicted image by performing motion compensation processing, etc., using the final motion vector (S208).

[0223] Thus, when processing a target block using merge mode or FRUC mode, significantly more processing is required to derive the final motion vector compared to using other modes. As a result, processing time increases, which leads to increased stage waiting times in the pipeline control explained in Figure 13.

[0224] Please note that the processing flow shown here is just one example, and you may omit some of the processes described or add processes that are not listed.

[0225] Furthermore, the encoding device 100 and the decoding device 200 differ only in whether they encode the signals necessary for processing into a stream or decode them from a stream; the processing flow described here is basically the same.

[0226] [Second example of interpretation processing] Figure 15 shows a second example of the schematic pipeline configuration used in the decoding device 200. In the second example shown in Figure 15, unlike the first example described in Figure 11, the decoding device 200 does not use the final motion vector (second motion vector) after all processing related to motion vector derivation has been performed as the peripheral reference motion vector of the surrounding decoded block used in the interprediction process, but rather uses a temporary motion vector (first motion vector) generated using one or more MVPs obtained in the MVP derivation process.

[0227] In this way, by using a temporary motion vector as a peripheral reference motion vector for deriving the MVP in the decoding process of subsequent blocks, the length of the feedback loop can be significantly shortened. As a result, the second stage, which had to be one long stage in the first example, can be divided into two short stages, the second and third stages, while satisfying the condition that the feedback loop does not span between stages.

[0228] Note that this pipeline configuration is just an example, and you may remove some of the processes described, add processes that are not listed, or change the way the stages are divided.

[0229] Figure 16 is a time sequence showing the processing timing of each stage processing for the blocks to be decoded in a second example of the pipeline configuration outlined in Figure 15.

[0230] Figure 16, similar to Figure 13, shows the processing timing for the five decoded blocks from encoding unit CU0 to encoding unit CU4, as shown in the block partitioning example in Figure 12. In the first example, the second stage was one long stage, but in the second example, it is divided into two short stages, the second stage and the third stage. The length of each of the second and third stages is the same as the length of the other stages.

[0231] Each stage of processing begins only after waiting for the corresponding stage of the preceding block to finish. For example, the second stage of encoding unit CU1 starts at time t4, when the second stage of encoding unit CU0 has finished. In this case, since the processing time for the second stage of encoding unit CU0 is the same as that of the other stages, encoding unit CU1 can start the second stage without any waiting time after the first stage has finished.

[0232] On the other hand, because encoding unit CU2 has a smaller block size than the preceding encoding unit CU1 in terms of processing order, a waiting time occurs between the first and second stages. However, this waiting time does not accumulate, and by the time encoding unit CU4 is reached, there is no waiting time.

[0233] As a result, even when the decoding process for one picture is complete, the total processing time, including waiting time, is almost the same as the original processing time, making it highly likely that all blocks can be processed within the processing time allocated to one picture.

[0234] Figure 17 is a flowchart of the inter-prediction process in a second example of the pipeline configuration outlined in Figure 15. The process shown in Figure 17 is repeated in units of prediction blocks, which are the processing units of inter-screen prediction. The process shown in Figure 17 is performed in the encoding device 100 and the decoding device 200. In the following, the operation of the inter-prediction unit 126 included in the encoding device 100 will be mainly described, but the operation of the inter-prediction unit 218 included in the decoding device 200 is similar.

[0235] The process shown in Figure 17 differs from the first example described in Figure 14 in the following respects. In the process shown in Figure 17, the final motion vectors derived by each method are not stored in the peripheral reference motion vector memory. Instead, temporary motion vectors derived using one or more MVPs obtained by each method are stored in the peripheral reference motion vector memory.

[0236] This makes it possible to provide feedback of peripheral reference motion vectors for deriving the MVP in the processing of subsequent blocks at an earlier stage in the processing flow. Therefore, as explained in Figure 16, there is a high possibility that the waiting time of stages in pipeline control can be significantly reduced.

[0237] The temporary motion vectors to be stored in the peripheral reference motion vector memory are derived as follows.

[0238] (1) In normal inter mode, the inter prediction unit 126 determines the final motion vector obtained through the normal motion vector derivation process as a provisional motion vector.

[0239] (2) In merge mode, the interpretation unit 126 determines the MVP (optimal MVP) specified by the merge index from among the multiple MVPs shown in the merge MVP list as a provisional motion vector.

[0240] (3) In FRUC mode, the interpretation unit 126 uses multiple MVPs indicated in the FRUC MVP list to derive a provisional motion vector using, for example, one of the following methods: The interpretation unit 126 determines the MVP registered at the beginning of the FRUC MVP list as the provisional motion vector. Alternatively, the interpretation unit 126 scales each of the multiple MVPs indicated in the FRUC MVP list to the time interval of the nearest reference picture. The interpretation unit 126 calculates the average or median value of the multiple MVPs obtained by scaling for both the L0 and L1 directions, and determines the obtained motion vector as the provisional motion vector.

[0241] The interpretation unit 126 may also derive a provisional motion vector by excluding the MVP that was registered by referring to a provisional motion vector from among the multiple MVPs shown in the FRUC MVP list, and applying one of the above methods to the remaining MVPs.

[0242] Furthermore, in Figure 17, the temporary motion vector stored in the peripheral reference motion vector memory is used as the peripheral reference motion vector for deriving the MVP. However, the temporary motion vector may also be used as the peripheral reference motion vector in other processes, such as loop filtering. Note that in other processes, such as loop filtering, the final motion vector used for motion compensation may be used instead of the temporary motion vector. Specifically, the final motion vector is derived in the third stage shown in Figure 15. Therefore, this final motion vector may be used in the processes from the fourth stage onward.

[0243] Furthermore, in the pipeline configuration shown in Figure 15, which assumes this processing flow, a temporary motion vector is fed back as a peripheral reference motion vector immediately after the MVP derivation process. However, if the same information as the temporary motion vector described here can be obtained, the temporary motion vector may be fed back at any other time.

[0244] Note that this processing flow is just one example, and you may omit some of the processes described or add processes that are not listed. For example, in merge mode, if you do not perform the peripheral search process for the optimal MVP, the provisional motion vector may be the same as the final motion vector.

[0245] Furthermore, the encoding device 100 and the decoding device 200 differ only in whether they encode the signals necessary for processing into a stream or decode them from a stream; the processing flow described here is basically the same.

[0246] [Effect of the second example of interpredictive processing] With the configuration described with reference to FIGS. 15 to 17, it becomes possible to feed back peripheral reference motion vectors for deriving MVP in subsequent block processing at an early stage of the processing flow. Therefore, the stage waiting time in pipeline control that occurred in the first example is greatly reduced. This increases the possibility that even a decoding device with low processing performance can complete processing of all blocks within the processing time allocated to one picture.

[0247] [Third Example of Inter Prediction Processing] FIG. 18 is a diagram showing a third schematic example of a pipeline configuration used in the decoding device 200. In the third example shown in FIG. 18, unlike the first example described with reference to FIG. 11, the decoding device 200 uses, as the peripheral reference motion vector of neighboring decoded blocks used for MVP derivation in inter prediction processing, does not use the final motion vector after all processing related to motion vector derivation is completed. When the inter prediction mode is the FRUC mode, it uses a provisional motion vector before performing the optimal MVP peripheral search, and when the inter prediction mode is the merge mode, it uses a provisional motion vector before performing DMVR processing.

[0248] As described above, by using a provisional motion vector as the peripheral reference motion vector for deriving MVP in the decoding processing of subsequent blocks, the length of the feedback loop can be made relatively short. This allows the peripheral reference motion vector to be fed back at an early stage of the third stage. Therefore, if the start timing of MVP derivation processing for a subsequent block can be delayed until the provisional motion vector is determined, the second stage, which had to be a single long stage in the first example, can be divided into two short stages: the second stage and the third stage.

[0249] Note that the outline of this pipeline configuration is an example, and some of the described processes may be removed, processes not described herein may be added, or the method of dividing stages may be changed.

[0250] FIG. 19 is a diagram illustrating, as a time sequence, processing timing of stage processing for each block to be decoded in a third schematic example of the pipeline configuration described in FIG. 18.

[0251] Similar to FIG. 13, FIG. 19 illustrates processing timing for five blocks to be decoded from coding unit CU0 to coding unit CU4 shown in the block division example illustrated in FIG. 12. The second stage, which was one long stage in the first example, is divided into two short stages, the second stage and the third stage, in the third example. Here, the second stage is shorter than the other stages. This is because the processing of the second stage has a small processing volume that includes only MVP derivation and reference picture memory transfer. It is assumed herein that the speed of reference picture memory transfer is sufficiently high.

[0252] Processing at each stage is started after waiting for the same stage of the immediately preceding block in the processing order to finish. However, as an exception in the third example, the second stage is started at timing after a provisional motion vector is determined in the third stage of the immediately preceding block in the processing order. Therefore, for example, the processing of the second stage of coding unit CU1 is started from time t4 when the first half processing of the third stage of coding unit CU0 is completed. At this time, since the processing time of the second stage of coding unit CU0 is sufficiently shorter compared to other stages, in coding unit CU1, the processing of the second stage can be started without waiting time after the processing of the first stage is completed.

[0253] On the other hand, for example, the processing of the second stage of coding unit CU3 is started after the first half processing of the third stage of coding unit CU2 is completed, but since the processing time of the second stage of coding unit CU2 is not sufficiently short compared to other stages, a slight increase in waiting time occurs.

[0254] As a result, compared to the second example explained in Figure 16, a waiting time from time t8 to time t9 occurs between the first and second stages when the encoding unit CU4 is processed. However, compared to the first example explained in Figure 13, the waiting time is significantly reduced, and even at the completion of decoding one picture, the processing time including the waiting time is almost the same as the original processing time. Therefore, there is a higher probability that the processing of all blocks can be completed within the processing time allocated to one picture.

[0255] Figure 20 is a flowchart of the inter-prediction process in the third example of the pipeline configuration outlined in Figure 18. The process shown in Figure 20 is repeated in units of prediction blocks, which are the processing units of inter-screen prediction. The process shown in Figure 17 is performed in the encoding device 100 and the decoding device 200. In the following, the operation of the inter-prediction unit 126 included in the encoding device 100 will be mainly described, but the operation of the inter-prediction unit 218 included in the decoding device 200 is similar.

[0256] The process shown in Figure 20 differs from the first example explained in Figure 14 in the following respects. In the process shown in Figure 20, instead of using the final motion vector derived by each method as the motion vector for peripheral reference, a temporary motion vector, which is an intermediate value in the process of deriving the motion vector by each method, is stored in the motion vector memory for peripheral reference.

[0257] This makes it possible to provide feedback of peripheral reference motion vectors for deriving the MVP in the processing of subsequent blocks at an earlier stage in the processing flow. Therefore, as explained in Figure 19, there is a high possibility that the waiting time of stages in pipeline control can be significantly reduced.

[0258] The temporary motion vectors to be stored in the peripheral reference motion vector memory are derived as follows.

[0259] (1) In normal inter mode, the inter prediction unit 126 determines the final motion vector obtained through the normal motion vector derivation process as a provisional motion vector.

[0260] (2) In merge mode, the interpretation unit 126 determines the MVP (optimal MVP) specified by the merge index from among the multiple MVPs shown in the merge MVP list as a provisional motion vector.

[0261] (3) In FRUC mode, the interpretation unit 126 determines the MVP (optimal MVP) that has the smallest cost value among the multiple MVPs shown in the FRUC MVP list, using the bilateral matching method or the template matching method, as a provisional motion vector.

[0262] Furthermore, in Figure 20, the motion vector stored in the peripheral reference motion vector memory is used as the peripheral reference motion vector for deriving the MVP, but the temporary motion vector may be used as the peripheral reference motion vector in other processes, such as loop filtering. Note that in other processes such as loop filtering, the final motion vector used for motion compensation may be used instead of the temporary motion vector. Specifically, the final motion vector is derived in the third stage shown in Figure 18. Therefore, this final motion vector may be used in the processes from the fourth stage onward.

[0263] Furthermore, in the pipeline configuration shown in Figure 18, which assumes this processing flow, a temporary motion vector is fed back as a motion vector for peripheral reference immediately before the optimal MVP peripheral search process and the DMVR process. However, if the same information as the temporary motion vector described here can be obtained, the temporary motion vector may be fed back at other times.

[0264] Note that this processing flow is just one example, and you may omit some of the processes described or add processes that are not listed. For example, in merge mode or FRUC mode, if you do not perform the peripheral search process for the optimal MVP, the provisional motion vector may be the same as the final motion vector.

[0265] Furthermore, the encoding device 100 and the decoding device 200 differ only in whether they encode the signals necessary for processing into a stream or decode them from a stream; the processing flow described here is basically the same.

[0266] [Effects of the third example of interpredictive processing] The configuration described using Figures 18 to 20 makes it possible to provide feedback of peripheral reference motion vectors for deriving the MVP in the processing of subsequent blocks at an early stage in the processing flow. Therefore, the stage waiting time in pipeline control that occurred in the first example is significantly reduced. As a result, even a decoder with low processing performance is more likely to be able to complete the processing of all blocks within the processing time allocated to one picture.

[0267] Furthermore, compared to the second example explained in Figure 17, when the interpretation mode is FRUC mode, the motion vector that has undergone optimal MVP determination processing can be used as the peripheral reference motion vector. Therefore, the possibility of improving coding efficiency increases as a more reliable motion vector becomes available for reference.

[0268] [Peripheral reference motion vector combining the final motion vector and a provisional motion vector] In the second example described in Figure 17 and the third example described in Figure 20, in addition to storing temporary motion vectors in the peripheral reference motion vector memory, the final motion vectors may also be stored there, similar to the first example described in Figure 14.

[0269] Accordingly, in the MVP derivation process for a subsequent block, the inter prediction unit 126 can acquire a final motion vector as a motion vector for peripheral reference from a block from which the final motion vector can be acquired among the plurality of peripheral reference blocks, and acquire a temporary motion vector as a motion vector for peripheral reference from a block from which the final motion vector cannot be acquired.

[0270] FIG. 21 and FIG. 22 are diagrams for explaining peripheral blocks referred to for MVP derivation of a target block. A coding unit CU4 is the target block, coding units CU0 to CU3 are spatial peripheral blocks for which processing has already been completed, and a coding unit CU col is a temporal peripheral block belonging to the same position of another picture for which processing has already been completed.

[0271] FIG. 21 is a diagram illustrating an example where a final motion vector cannot be acquired in the block immediately preceding the target block in processing order. In this example, the inter prediction unit 126 acquires a temporary motion vector as a motion vector for peripheral reference for the coding unit CU3, and acquires a final motion vector as a motion vector for peripheral reference for other blocks. Note that the coding unit CU col is a block belonging to a picture for which processing has already been completed. Therefore, the inter prediction unit 126 acquires the final motion vector as the motion vector for peripheral reference for the coding unit CU col.

[0272] Figure 22 shows an example where the final motion vector cannot be obtained for a target block in the two blocks immediately preceding it in the processing order. In this example, the interpretation unit 126 obtains temporary motion vectors as peripheral reference motion vectors for encoding units CU2 and CU3, and obtains the final motion vectors as peripheral reference motion vectors for the other blocks. Note that encoding unit CU col is a block belonging to a picture whose processing has already been completed. Therefore, the interpretation unit 126 obtains the final motion vector for encoding unit CU col as a peripheral reference motion vector.

[0273] In this way, the interpretation unit 126 obtains the final motion vector as the peripheral reference motion vector from the peripheral reference blocks where the final motion vector can be obtained. Compared to the case where all provisional motion vectors are obtained as peripheral reference motion vectors, the MVP derivation can be performed by referencing a more reliable motion vector. This increases the likelihood of improving coding efficiency.

[0274] The interpretation unit 126 may switch the motion vectors it can reference depending on whether the boundary of the target block is the boundary of the CTU. For example, if the target block is not adjacent to the upper boundary of the CTU, the interpretation unit 126 decides whether to refer to the final motion vector or a provisional motion vector for the block adjacent to the upper side of the target block, as described in Figures 21 and 22. On the other hand, if the target block is adjacent to the upper boundary of the CTU, the interpretation unit 126 always refers to the final motion vector for the block adjacent to the upper side of the target block, since the derivation of the final motion vector has been completed. Similarly, if the target block is adjacent to the left boundary of the CTU, the interpretation unit 126 always refers to the final motion vector for the block adjacent to the left side of the target block.

[0275] [A combination of the first example, the second example, and the third example] A processing flow combining the first example described in Figure 14, the second example described in Figure 17, and the third example described in Figure 20 may also be used.

[0276] As a specific example, the interpretation unit 126 may, if the interpretation mode is merge mode, use the final motion vector as the peripheral reference motion vector, as in the first example, and if the interpretation mode is FRUC mode, it may use a temporary motion vector before optimal MVP peripheral search as the peripheral reference motion vector, as in the third example. Since the processing in merge mode is less computationally intensive than that in FRUC mode, even if the system waits until the final motion vector is determined and then feeds it back as the peripheral reference motion vector, it is possible to complete the processing of subsequent blocks within the required processing time. Therefore, it is possible to perform processing without accumulating waiting time at each stage in pipeline control. Furthermore, by making a more reliable motion vector available as the peripheral reference motion vector in merge mode, the coding efficiency is likely to be improved.

[0277] [Switching via low-latency mode signal] The interpretation unit 126 determines whether or not to process the stream to be processed in low-latency mode. If the stream to be processed is to be processed in low-latency mode, it may refer to a temporary motion vector as the peripheral reference motion vector in the MVP derivation process, as described in the second or third example. If the stream to be processed is not to be processed in low-latency mode, it may refer to the final motion vector as the peripheral reference motion vector in the MVP derivation process, as described in the first example.

[0278] This significantly reduces stage latency in pipeline control by shortening the length of the feedback loop for peripheral reference motion vectors in low-latency mode. On the other hand, in non-low-latency mode, stage latency occurs in pipeline control, but the ability to reference highly reliable motion vectors as peripheral reference motion vectors increases the likelihood of improved encoding efficiency.

[0279] The encoding device 100 generates information indicating whether or not to process in low-latency mode, and encodes the generated information into a stream. The decoding device 200 decodes and obtains this information from the stream, and determines whether or not to process in low-latency mode based on the obtained information. This information is written in the sequence header area, picture header area, slice header area, or auxiliary information area of ​​the stream to be processed.

[0280] For example, the encoding device 100 may switch whether or not to process in low-latency mode depending on the size of the picture to be encoded. For example, if the picture size is small, the encoding device 100 does not set to low-latency mode because there are fewer blocks to process and therefore ample processing time, but if the picture size is large, it sets to low-latency mode because there are many blocks to process and therefore not ample processing time.

[0281] Furthermore, the encoding device 100 may switch whether or not to process in low-latency mode depending on the processing capacity of the decoding device 200, the destination of the stream. For example, if the decoding device 200 has high processing capacity, the encoding device 100 will not set to low-latency mode because the decoding device 200 can perform many operations in a given processing time. On the other hand, if the decoding device 200 has low processing capacity, the encoding device 100 will set to low-latency mode because it cannot perform many operations in a given processing time.

[0282] Furthermore, the encoding device 100 may switch whether or not to process in low-latency mode depending on the profile or level information assigned to the stream to be encoded. For example, the encoding device 100 will not set to low-latency mode if the stream is assigned a profile and level that assumes sufficient processing capacity of the decoding device. On the other hand, the encoding device 100 will set to low-latency mode if the stream is assigned a profile and level that assumes insufficient processing capacity of the decoding device.

[0283] Furthermore, the information indicating whether or not to process in low-latency mode, which is encoded in the stream, does not necessarily have to be a signal that directly indicates whether or not to process in low-latency mode; it may be encoded as a signal with other meanings. For example, by directly associating the information indicating whether or not to process in low-latency mode with the profile and level, it may be possible to determine whether or not to process in low-latency mode using only the signals indicating the profile and level.

[0284] As described above, the encoding device 100 according to this embodiment, when encoding a target block in inter-prediction mode in which motion search is performed in the decoding device 200 (for example, merge mode or FRUC mode in S201 of Figure 17), derives a first motion vector of the target block (S203 or S205), stores the derived first motion vector in memory, derives a second motion vector of the target block (S204 or S207), and generates a predicted image of the target block by motion compensation using the second motion vector (S208). In deriving the first motion vector (S203 or S205), the encoding device 100 derives the first motion vector of the target block using the first motion vector of a processed block.

[0285] According to this, in pipeline control, the decoding device 200 can, for example, start deriving the first motion vector of the target block after the completion of deriving the first motion vector of the surrounding block, without waiting for the completion of deriving the second motion vector of the surrounding block. Therefore, compared to the case where the first motion vector is derived using the second motion vector of the surrounding block, the waiting time in the pipeline control of the decoding device 200 can be reduced, thereby reducing processing delays.

[0286] For example, in deriving the first motion vector, the encoding device 100 (i) generates a list of predicted motion vectors showing multiple predicted motion vectors using the first motion vector of the processed block, and (ii) determines the first motion vector of the target block from the multiple predicted motion vectors shown in the list of predicted motion vectors (for example, S203 or S205 in Figure 17).

[0287] For example, the interpretation mode in which motion search is performed in the decoding device 200 is a merge mode, and the encoding device 100 derives the second motion vector by performing motion search processing on the periphery of the first motion vector (for example, S204 in Figure 17).

[0288] For example, the interpretation mode used by the decoding device 200 for motion search is the FRUC mode, and the encoding device 100 derives the second motion vector by performing motion search processing on the periphery of the first motion vector (for example, S207 in Figure 20).

[0289] For example, the interprediction mode used by the decoding device 200 for motion search is the FRUC mode, and the encoding device 100, in deriving the second motion vector, (i) determines the third motion vector (optimal MVP) from a plurality of predicted motion vectors shown in the predicted motion vector list (for example, S206 in Figure 17), and (ii) derives the second motion vector by performing motion search processing on the vicinity of the third motion vector (for example, S207 in Figure 17).

[0290] For example, in determining the first motion vector (e.g., S205 in Figure 17), the encoding device 100 derives the first motion vector based on the average or median value for each prediction direction of a plurality of predicted motion vectors shown in the predicted motion vector list.

[0291] For example, in determining the first motion vector (e.g., S205 in Figure 17), the encoding device 100 determines the first motion vector to be the predicted motion vector shown at the beginning of the predicted motion vector list, out of the multiple predicted motion vectors shown in the predicted motion vector list.

[0292] For example, in generating a list of predicted motion vectors (e.g., S203 or S205 in Figure 17), the encoding device 100 derives each of a plurality of predicted motion vectors using the first or second motion vector of the processed block. In determining the first motion vector (e.g., S205 in Figure 17), the encoding device 100 determines the first motion vector from among the plurality of predicted motion vectors shown in the list of predicted motion vectors, from the candidate motion vectors derived using the second motion vector. This allows the first motion vector to be determined using a highly reliable second motion vector, thereby suppressing a decrease in the reliability of the first motion vector.

[0293] For example, in generating a list of predicted motion vectors (e.g., S203 or S205 in Figure 17), the encoding device 100 derives the predicted motion vector using the first motion vector of the processed block if the processed block belongs to the same picture as the target block, and derives the predicted motion vector using the second motion vector of the processed block if the processed block belongs to a different picture from the target block. This allows the encoding device 100 to improve the reliability of the predicted motion vector by using the second motion vector when the processed block belongs to a different picture from the target block.

[0294] For example, in generating a list of predicted motion vectors (e.g., S203 or S205 in Figure 17), the encoding device 100 determines whether to use the first motion vector of the processed block or the second motion vector of the processed block to derive the predicted motion vector, depending on the position of the processed block relative to the target block.

[0295] For example, in generating a predicted motion vector list (e.g., S203 or S205 in Figure 17), the encoding device 100 uses the second motion vector of the processed block to derive the predicted motion vector if the processed block belongs to a different processing unit (e.g., CTU) than the processing unit containing the target block.

[0296] For example, in generating a list of predicted motion vectors (e.g., S203 or S205 in Figure 17), the encoding device 100 derives predicted motion vectors using the first motion vector of processed blocks from among multiple processed blocks belonging to the same picture as the target block, for processed blocks that are N steps prior in processing order to the target block, and for processed blocks that are N steps prior in processing order and later, and for processed blocks that are N steps prior in processing order and earlier in processing order, it derives predicted motion vectors using the second motion vector of those processed blocks.

[0297] According to this, the encoding device 100 can improve the reliability of the predicted motion vector by using a second motion vector for processed blocks that are N processed blocks prior in the processing order.

[0298] For example, N is 1.

[0299] For example, the first motion vector is referenced in processes other than the derivation of the predicted motion vector. For instance, this other process is loop filtering.

[0300] For example, in loop filtering, a second motion vector is used.

[0301] For example, when encoding a target block in low-latency mode, the encoding device 100 derives the first motion vector of the target block using the first motion vector of the processed block.

[0302] According to this, the encoding device 100 can perform appropriate processing depending on whether or not to use the low-latency mode.

[0303] For example, the encoding device 100 encodes information indicating whether or not to encode the target block in low-latency mode in the sequence header area, picture header area, slice header area, or auxiliary information area.

[0304] For example, the encoding device 100 switches whether or not to encode the target block in low-latency mode depending on the size of the target picture that includes the target block.

[0305] For example, the encoding device 100 switches whether or not to encode the target block in low-latency mode, depending on the processing capacity of the decoding device.

[0306] For example, the encoding device 100 switches whether or not to encode the target block in low-latency mode, depending on the profile or level information assigned to the stream to be encoded.

[0307] In this embodiment, when the decoding device 200 encodes a target block in an inter-prediction mode in which motion search is performed in the decoding device 200 (for example, merge mode or FRUC mode in S201 of Figure 17), it derives a first motion vector of the target block (S203 or S205), stores the derived first motion vector in memory, derives a second motion vector of the target block (S204 or S207), and generates a predicted image of the target block by motion compensation using the second motion vector (S208). In deriving the first motion vector (S203 or S205), the decoding device 200 derives the first motion vector of the target block using the first motion vector of a processed block.

[0308] According to this, in pipeline control, the decoding device 200 can, for example, start deriving the first motion vector of the target block after the completion of deriving the first motion vector of the surrounding block, without waiting for the completion of deriving the second motion vector of the surrounding block. Therefore, compared to the case where the first motion vector is derived using the second motion vector of the surrounding block, the waiting time in the pipeline control of the decoding device 200 can be reduced, thereby reducing processing delays.

[0309] For example, in deriving the first motion vector, the decoding device 200 (i) generates a list of predicted motion vectors showing multiple predicted motion vectors using the first motion vector of the processed block, and (ii) determines the first motion vector of the target block from the multiple predicted motion vectors shown in the list of predicted motion vectors (for example, S203 or S205 in Figure 17).

[0310] For example, the interpretation mode in which motion search is performed in the decoding device 200 is a merge mode, and in the derivation of the second motion vector, the decoding device 200 derives the second motion vector by performing motion search processing on the periphery of the first motion vector (for example, S204 in Figure 17).

[0311] For example, the interpretation mode used by the decoding device 200 for motion search is the FRUC mode. In deriving the second motion vector, the decoding device 200 derives the second motion vector by performing motion search processing on the periphery of the first motion vector (for example, S207 in Figure 20).

[0312] For example, the interprediction mode used by the decoder 200 for motion search is the FRUC mode. In deriving the second motion vector, the decoder 200 (i) determines the third motion vector (optimal MVP) from a plurality of predicted motion vectors shown in the predicted motion vector list (for example, S206 in Figure 17), and (ii) derives the second motion vector by performing motion search processing around the third motion vector (for example, S207 in Figure 17).

[0313] For example, in determining the first motion vector (e.g., S205 in Figure 17), the decoding device 200 derives the first motion vector based on the average or median value for each prediction direction of a plurality of predicted motion vectors shown in the predicted motion vector list.

[0314] For example, in determining the first motion vector (e.g., S205 in Figure 17), the decoding device 200 determines the first motion vector to be the predicted motion vector shown at the beginning of the predicted motion vector list, out of the multiple predicted motion vectors shown in the predicted motion vector list.

[0315] For example, in generating a list of predicted motion vectors (e.g., S203 or S205 in Figure 17), the decoder 200 derives each of several predicted motion vectors using the first or second motion vector of the processed block. In determining the first motion vector (e.g., S205 in Figure 17), the decoder 200 determines the first motion vector from among the multiple predicted motion vectors shown in the list of predicted motion vectors, selected from the candidates derived using the second motion vector. This allows the first motion vector to be determined using a highly reliable second motion vector, thereby suppressing a decrease in the reliability of the first motion vector.

[0316] For example, in generating a predicted motion vector list (e.g., S203 or S205 in Figure 17), the decoder 200 derives a predicted motion vector using the first motion vector of the processed block if the processed block belongs to the same picture as the target block, and derives a predicted motion vector using the second motion vector of the processed block if the processed block belongs to a different picture from the target block. This allows the decoder 200 to improve the reliability of the predicted motion vector by using the second motion vector when the processed block belongs to a different picture from the target block.

[0317] For example, in generating a predicted motion vector list (e.g., S203 or S205 in Figure 17), the decoding device 200 determines whether to use the first motion vector of the processed block or the second motion vector of the processed block to derive the predicted motion vector, depending on the position of the processed block relative to the target block.

[0318] For example, in generating a predicted motion vector list (e.g., S203 or S205 in Figure 17), the decoding device 200 uses the second motion vector of the processed block to derive the predicted motion vector if the processed block belongs to a different processing unit (e.g., CTU) than the processing unit containing the target block.

[0319] For example, in generating a predicted motion vector list (e.g., S203 or S205 in Figure 17), the decoding device 200 derives a predicted motion vector from the first motion vector of a processed block among multiple processed blocks belonging to the same picture as the target block, for processed blocks that are N positions prior in processing order to the target block, and for processed blocks that are N positions prior in processing order or later, it derives a predicted motion vector from the second motion vector of a processed block that is N positions prior in processing order.

[0320] According to this, the decoding device 200 can improve the reliability of the predicted motion vector by using a second motion vector for processed blocks that are N processed blocks prior in the processing order.

[0321] For example, N is 1.

[0322] For example, the first motion vector is referenced in processes other than the derivation of the predicted motion vector. For instance, this other process is loop filtering.

[0323] For example, in loop filtering, a second motion vector is used.

[0324] For example, when the decoding device 200 decodes a target block in low-latency mode, the first motion vector of the target block is derived using the first motion vector of the processed block.

[0325] According to this, the decoding device 200 can perform appropriate processing depending on whether or not it uses the low-latency mode.

[0326] For example, the decoding device 200 decodes information from the sequence header area, picture header area, slice header area, or auxiliary information area indicating whether or not to decode the target block in low-latency mode, and determines whether or not to decode the target block in low-latency mode based on this information.

[0327] For example, as shown in Figure 15, the pipeline structure of the decoder 200 includes a first stage (second stage in Figure 15) that performs the process of deriving the first motion vector of the target block, and a second stage (third stage in Figure 15) separate from the first stage that performs the process of deriving the second motion vector of the target block. The decoder 200 does not wait for the completion of the second stage processing of the blocks up to M blocks prior in processing order to the target block, but starts processing the first stage of the target block as soon as the processing of the first stage of the immediately preceding block in processing order is completed.

[0328] For example, as shown in Figure 18, the pipeline structure of the decoder 200 includes a first stage (second stage in Figure 18) that performs the process of deriving the first motion vector of the target block, and a second stage (third stage in Figure 18) separate from the first stage that performs the process of deriving the second motion vector of the target block. The decoder 200 does not wait for the completion of the second stage processing of the blocks up to M blocks prior in processing order to the target block, but starts processing the first stage of the target block as soon as the first motion vector of the M blocks prior in processing order is derived.

[0329] For example, M is 1.

[0330] Furthermore, the encoding device 100 according to this embodiment includes: a division unit 102 that divides an image into a plurality of blocks; an intra prediction unit 124 that predicts the blocks included in the image using a reference picture included in the image; an inter prediction unit 126 that predicts the blocks included in the image using a reference block included in another image different from the image; a loop filter unit 120 that applies a filter to the blocks included in the image; a conversion unit 106 that converts the prediction error between the predicted signal generated by the intra prediction unit 124 or the inter prediction unit 126 and the original signal to generate conversion coefficients; a quantization unit 108 that quantizes the conversion coefficients to generate quantization coefficients; and an entropy encoding unit 110 that generates an encoded bitstream by variable-length encoding the quantization coefficients. The interprediction unit 126, when encoding a target block in an interprediction mode in which motion search is performed in the decoding device 200 (for example, merge mode or FRUC mode in S201 of Figure 17), derives a first motion vector of the target block (S203 or S205), stores the derived first motion vector in memory, derives a second motion vector of the target block (S204 or S207), and generates a predicted image of the target block by motion compensation using the second motion vector (S208). The encoding device 100 derives the first motion vector of the target block using the first motion vector of a processed block.

[0331] Furthermore, the decoding device 200 according to this embodiment includes a decoding unit (entropy decoding unit 202) that decodes an encoded bitstream and outputs quantization coefficients, an inverse quantization unit 204 that inversely quantizes the quantization coefficients and outputs conversion coefficients, an inverse conversion unit 206 that inversely converts the conversion coefficients and outputs a prediction error, an intra prediction unit 216 that predicts blocks included in the image using reference pictures included in the image, an inter prediction unit 218 that predicts blocks included in the image using reference blocks included in other images different from the image, and a loop filter unit 212 that applies a filter to the blocks included in the image. The interprediction unit 218, when encoding a target block in an interprediction mode in which motion search is performed in the decoding device 200 (for example, merge mode or FRUC mode in S201 of Figure 17), derives a first motion vector of the target block (S203 or S205), stores the derived first motion vector in memory, derives a second motion vector of the target block (S204 or S207), and generates a predicted image of the target block by motion compensation using the second motion vector (S208). The encoding device 100 derives the first motion vector of the target block using the first motion vector of a processed block.

[0332] [Example of an encoding device implementation] Figure 23 is a block diagram showing an example of the implementation of the encoding device 100 according to Embodiment 1. The encoding device 100 includes a circuit 160 and a memory 162. For example, the multiple components of the encoding device 100 shown in Figure 1 are implemented by the circuit 160 and memory 162 shown in Figure 23.

[0333] Circuit 160 is an information processing circuit and is a circuit that can access memory 162. For example, circuit 160 is a dedicated or general-purpose electronic circuit for encoding moving images. Circuit 160 may also be a processor such as a CPU. Alternatively, circuit 160 may be a collection of multiple electronic circuits. Furthermore, for example, circuit 160 may play the role of multiple components of the encoding device 100 shown in Figure 1, etc., excluding the component for storing information.

[0334] Memory 162 is a dedicated or general-purpose memory in which information for the circuit 160 to encode moving images is stored. Memory 162 may be an electronic circuit, or it may be connected to circuit 160. Memory 162 may also be included in circuit 160. Memory 162 may also be a collection of multiple electronic circuits. Memory 162 may also be a magnetic disk or an optical disk, or it may be described as storage or a recording medium. Memory 162 may also be a non-volatile memory or a volatile memory.

[0335] For example, memory 162 may store the video to be encoded, or it may store a bit sequence corresponding to the encoded video. Alternatively, memory 162 may store a program for circuit 160 to encode the video.

[0336] Furthermore, for example, memory 162 may play the role of an information storage component among the multiple components of the encoding device 100 shown in Figure 1, etc. Specifically, memory 162 may play the role of block memory 118 and frame memory 122 shown in Figure 1. More specifically, reconstructed blocks and reconstructed pictures may be stored in memory 162.

[0337] Furthermore, it is not necessary for the encoding device 100 to implement all of the components shown in Figure 1, etc., nor is it necessary for all of the processes described above to be performed. Some of the components shown in Figure 1, etc., may be included in other devices, and some of the processes described above may be executed by other devices. Then, in the encoding device 100, motion compensation is efficiently performed by implementing some of the components shown in Figure 1, etc., and by performing some of the processes described above.

[0338] [Example of a decryption device implementation] Figure 24 is a block diagram showing an example of the implementation of the decoding device 200 according to Embodiment 1. The decoding device 200 includes a circuit 260 and a memory 262. For example, the multiple components of the decoding device 200 shown in Figure 10 are implemented by the circuit 260 and memory 262 shown in Figure 24.

[0339] Circuit 260 is an information processing circuit and is a circuit that can access memory 262. For example, circuit 260 is a dedicated or general-purpose electronic circuit for decoding moving images. Circuit 260 may also be a processor such as a CPU. Alternatively, circuit 260 may be a collection of multiple electronic circuits. Furthermore, for example, circuit 260 may play the role of multiple components of the decoding device 200 shown in Figure 10, etc., excluding the component for storing information.

[0340] Memory 262 is a dedicated or general-purpose memory in which information for the circuit 260 to decode moving images is stored. Memory 262 may be an electronic circuit, or it may be connected to the circuit 260. Alternatively, memory 262 may be included in the circuit 260. Alternatively, memory 262 may be a collection of multiple electronic circuits. Alternatively, memory 262 may be a magnetic disk or an optical disk, or it may be described as storage or a recording medium. Alternatively, memory 262 may be a non-volatile memory or a volatile memory.

[0341] For example, memory 262 may store a bit sequence corresponding to an encoded video, or a video corresponding to a decoded bit sequence. Memory 262 may also store a program for circuit 260 to decode the video.

[0342] Furthermore, for example, memory 262 may play the role of an information storage component among the multiple components of the decoding device 200 shown in Figure 10, etc. Specifically, memory 262 may play the role of block memory 210 and frame memory 214 shown in Figure 10. More specifically, reconstructed blocks and reconstructed pictures, etc., may be stored in memory 262.

[0343] Furthermore, it is not necessary for the decoding device 200 to implement all of the components shown in Figure 10, etc., nor is it necessary for all of the processes described above to be performed. Some of the components shown in Figure 10, etc., may be included in other devices, and some of the processes described above may be performed by other devices. Then, motion compensation is efficiently performed in the decoding device 200 by implementing some of the components shown in Figure 10, etc., and performing some of the processes described above.

[0344] [supplement] Furthermore, the encoding device 100 and decoding device 200 in this embodiment may be used as an image encoding device and an image decoding device, respectively, or as a video encoding device and a video decoding device. Alternatively, the encoding device 100 and decoding device 200 may be used as inter-prediction devices (inter-screen prediction devices), respectively.

[0345] In other words, the encoding device 100 and the decoding device 200 may correspond only to the inter-prediction unit (inter-screen prediction unit) 126 and the inter-prediction unit (inter-screen prediction unit) 218, respectively. Other components such as the conversion unit 106 and the inverse conversion unit 206 may be included in other devices.

[0346] Furthermore, in this embodiment, each component may be implemented by being composed of dedicated hardware or by executing a software program suitable for each component. Each component may also be implemented by a program execution unit such as a CPU or processor reading and executing a software program recorded on a recording medium such as a hard disk or semiconductor memory.

[0347] Specifically, each of the encoding device 100 and the decoding device 200 may include a processing circuitry and a storage device electrically connected to and accessible from the processing circuitry. For example, the processing circuitry corresponds to circuit 160 or 260, and the storage device corresponds to memory 162 or 262.

[0348] The processing circuit includes at least one of dedicated hardware and a program execution unit, and performs processing using a memory device. Furthermore, if the processing circuit includes a program execution unit, the memory device stores the software program executed by that program execution unit.

[0349] Here, the software that implements the encoding device 100 or decoding device 200, etc., in this embodiment is the following program.

[0350] Furthermore, each component may be a circuit, as described above. These circuits may form a single circuit as a whole, or they may be separate circuits. Also, each component may be implemented using a general-purpose processor, or it may be implemented using a dedicated processor.

[0351] Furthermore, a process performed by one component may be performed by another component. Also, the order in which processes are executed may be changed, and multiple processes may be executed in parallel. Additionally, the encoding / decoding device may comprise an encoding device 100 and a decoding device 200.

[0352] Although the embodiments of the encoding device 100 and the decoding device 200 have been described above based on these embodiments, the embodiments of the encoding device 100 and the decoding device 200 are not limited to these embodiments. Without departing from the spirit of this disclosure, various modifications that a person skilled in the art could conceive of are applied to these embodiments, and configurations constructed by combining components from different embodiments may also be included within the scope of the embodiments of the encoding device 100 and the decoding device 200.

[0353] This embodiment may be implemented in combination with at least some of the other embodiments of this disclosure. Furthermore, some of the processes, some of the configurations of the apparatus, some of the syntax, etc., described in the flowchart of this embodiment may be implemented in combination with the other embodiments.

[0354] (Embodiment 2) In each of the above embodiments, each functional block can typically be implemented by an MPU and memory, etc. Furthermore, the processing performed by each functional block is typically implemented by a program execution unit such as a processor reading and executing software (program) recorded on a recording medium such as ROM. This software may be distributed by download, etc., or it may be recorded on a recording medium such as semiconductor memory and distributed. Of course, it is also possible to implement each functional block by hardware (dedicated circuitry).

[0355] Furthermore, the processing described in each embodiment may be implemented by centralized processing using a single device (system), or by distributed processing using multiple devices. Also, the processor executing the above program may be one or multiple. In other words, centralized processing may be performed, or distributed processing may be performed.

[0356] The embodiments of this disclosure are not limited to those described above, and various modifications are possible, which are also included within the scope of the embodiments of this disclosure.

[0357] Furthermore, here we will describe application examples of the video encoding method (image encoding method) or video decoding method (image decoding method) shown in each of the above embodiments, and a system using the same. The system is characterized by having an image encoding device using the image encoding method, an image decoding device using the image decoding method, and an image encoding and decoding device that includes both. Other configurations in the system can be appropriately modified as needed.

[0358] [Usage example] Figure 25 shows the overall configuration of the content supply system ex100 that realizes the content distribution service. The communication service area is divided into desired sizes, and fixed radio stations, base stations ex106, ex107, ex108, ex109, and ex110, are installed in each cell.

[0359] In this content supply system ex100, various devices such as a computer ex111, a game console ex112, a camera ex113, a home appliance ex114, and a smartphone ex115 are connected to the internet ex101 via an internet service provider ex102 or a communication network ex104, and base stations ex106~ex110. The content supply system ex100 may also connect any combination of the above elements. Each device may be directly or indirectly connected to each other via a telephone network or short-range radio, etc., without going through the base stations ex106~ex110, which are fixed radio stations. In addition, the streaming server ex103 is connected to various devices such as a computer ex111, a game console ex112, a camera ex113, a home appliance ex114, and a smartphone ex115 via the internet ex101, etc. Furthermore, the streaming server ex103 is connected to terminals in a hotspot on an airplane ex117 via satellite ex116.

[0360] Note that instead of base stations ex106~ex110, wireless access points or hotspots may be used. Also, streaming server ex103 may be connected directly to the communication network ex104 without going through the internet ex101 or internet service provider ex102, or it may be connected directly to the airplane ex117 without going through satellite ex116.

[0361] Camera ex113 is a device capable of taking still images and videos, such as a digital camera. Smartphone ex115 is a smartphone, mobile phone, or PHS (Personal Handyphone System) that supports mobile communication systems generally known as 2G, 3G, 3.9G, 4G, and the upcoming 5G.

[0362] Home appliance ex118 refers to appliances such as refrigerators or equipment included in household fuel cell cogeneration systems.

[0363] In the content supply system ex100, live streaming becomes possible when a terminal with a shooting function is connected to the streaming server ex103 via a base station ex106 or the like. In live streaming, the terminal (computer ex111, game console ex112, camera ex113, home appliance ex114, smartphone ex115, and terminal inside an airplane ex117, etc.) performs the encoding process described in each of the above embodiments on still images or video content captured by the user using the terminal, multiplexes the video data obtained by encoding with sound data encoded from the sound corresponding to the video, and transmits the obtained data to the streaming server ex103. In other words, each terminal functions as an image encoding device according to one aspect of this disclosure.

[0364] Meanwhile, the streaming server ex103 streams the content data sent to the requesting client. The client is a computer ex111, a game console ex112, a camera ex113, a home appliance ex114, a smartphone ex115, or a terminal on an airplane ex117, etc., that is capable of decoding the encoded data. Each device that receives the distributed data decodes and plays back the received data. That is, each device functions as an image decoding device according to one aspect of this disclosure.

[0365] [Distributed Processing] Furthermore, the streaming server ex103 may consist of multiple servers or computers that distribute data processing, recording, and distribution. For example, the streaming server ex103 may be implemented using a CDN (Content Delivery Network), where content delivery is achieved through a network connecting numerous edge servers distributed worldwide. In a CDN, the physically closest edge server is dynamically assigned depending on the client. Latency can be reduced by caching and delivering content to the edge server. In addition, if an error occurs or the communication state changes due to an increase in traffic, processing can be distributed among multiple edge servers, the delivery entity can be switched to another edge server, or delivery can be continued by bypassing the failed part of the network, thus enabling high-speed and stable delivery.

[0366] Furthermore, beyond the distributed processing of the distribution itself, the encoding process of the captured data can be performed on each terminal, on the server side, or shared among them. For example, encoding generally involves two processing loops. In the first loop, the complexity or code amount of the image at the frame or scene level is detected. In the second loop, processing is performed to improve encoding efficiency while maintaining image quality. For example, if the terminal performs the first encoding process and the server that receives the content performs the second encoding process, it is possible to improve the quality and efficiency of the content while reducing the processing load on each terminal. In this case, if there is a request to receive and decode near real time, the first encoded data from the terminal can be received and played back on other terminals, enabling more flexible real-time distribution.

[0367] Another example is the camera ex113, which extracts features from an image, compresses the feature data as metadata, and sends it to the server. The server performs compression according to the meaning of the image, for example, by determining the importance of an object from the features and switching the quantization precision. Feature data is particularly effective in improving the accuracy and efficiency of motion vector prediction during further compression on the server. Alternatively, a simple encoding such as VLC (Variable Length Coding) may be performed on the terminal, and a more computationally intensive encoding such as CABAC (Context-Adaptive Binary Arithmetic Coding) may be performed on the server.

[0368] Another example is a scenario in a stadium, shopping mall, or factory where multiple video data sets of nearly identical scenes may exist, captured by multiple terminals. In such cases, the encoding process is distributed among the multiple terminals that captured the footage, along with other terminals and servers as needed, by assigning encoding tasks to each unit, for example, at the Group of Picture (GOP) level, picture level, or tile level (a division of a picture). This reduces latency and enables more real-time performance.

[0369] Furthermore, since multiple video data sets depict essentially the same scene, the server may manage and / or instruct the video data captured by each terminal to reference each other. Alternatively, the server may receive the encoded data from each terminal, change the reference relationships between the multiple data sets, or correct or replace the pictures themselves and re-encode them. This allows for the creation of a stream with improved quality and efficiency for each individual data set.

[0370] Furthermore, the server may transcode the video data to change its encoding method before distributing it. For example, the server may convert an MPEG-based encoding to a VP-based encoding, or convert H.264 to H.265.

[0371] Thus, the encoding process can be performed by a terminal or one or more servers. Therefore, in the following, the terms "server" or "terminal" will be used to refer to the entity performing the processing, but some or all of the processing performed by the server may be performed by the terminal, and some or all of the processing performed by the terminal may be performed by the server. The same applies to the decoding process.

[0372] [3D, Multi-angle] In recent years, it has become increasingly common to integrate and utilize images or videos of different scenes, or the same scene, captured from different angles, using multiple cameras ex113 and / or smartphones ex115, which are nearly synchronized with each other. The videos captured by each device are integrated based on the relative positional relationship between the devices, or on areas where feature points contained in the videos coincide, which are acquired separately.

[0373] The server may not only encode 2D video but also encode still images automatically based on scene analysis of the video, or at a time specified by the user, and send them to the receiving terminal. Furthermore, if the server can obtain the relative positional relationship between the shooting terminals, it can generate a 3D shape of the scene based not only on 2D video but also on video of the same scene taken from different angles. The server may also separately encode 3D data generated by a point cloud, or it may select or reconstruct video to send to the receiving terminal from video taken by multiple terminals based on the results of recognizing or tracking a person or object using the 3D data.

[0374] In this way, users can enjoy scenes by arbitrarily selecting each video corresponding to each shooting terminal, or they can enjoy content in which video from an arbitrary viewpoint is extracted from 3D data reconstructed using multiple images or videos. Furthermore, just like the video, sound can also be collected from multiple different angles, and the server may multiplex and transmit sound from a specific angle or space in conjunction with the video.

[0375] In recent years, content that links the real world with a virtual world, such as Virtual Reality (VR) and Augmented Reality (AR), has also become popular. In the case of VR images, the server may create separate viewpoint images for the right and left eyes and perform encoding that allows referencing between the viewpoint images using Multi-View Coding (MVC), or it may encode them as separate streams without referencing each other. When decoding the separate streams, it is advisable to synchronize playback so that the virtual 3D space is reproduced according to the user's viewpoint.

[0376] In the case of AR images, the server superimposes virtual object information from the virtual space onto camera information from the real space, based on its three-dimensional position or the user's viewpoint movement. The decoding device may acquire or store the virtual object information and three-dimensional data, generate a two-dimensional image according to the user's viewpoint movement, and create superimposed data by smoothly stitching them together. Alternatively, the decoding device may send the user's viewpoint movement to the server in addition to requesting virtual object information, and the server may create superimposed data from the three-dimensional data held by the server according to the received viewpoint movement, encode the superimposed data, and distribute it to the decoding device. The superimposed data may have an α value indicating transparency in addition to RGB, and the server may set the α value of parts other than the object created from the three-dimensional data to 0, etc., so that those parts are transparent, and encode the data. Alternatively, the server may set a predetermined RGB value to the background, like chroma keying, and generate data in which parts other than the object are the background color.

[0377] Similarly, the decryption process of the distributed data can be performed on each client terminal, on the server side, or shared between them. For example, one terminal may send a reception request to the server, and other terminals may receive the content corresponding to that request, perform the decryption process, and then transmit the decrypted signal to a device with a display. By distributing the processing and selecting appropriate content regardless of the performance of the communication-capable terminals themselves, it is possible to play back data with good image quality. Another example is that while receiving large image data on a TV or similar device, a portion of the picture, such as tiles, may be decrypted and displayed on the viewer's personal terminal. This allows for sharing the overall picture while allowing users to check their own area of ​​responsibility or areas they want to examine in more detail on their own device.

[0378] In the future, it is expected that content will be seamlessly received by switching appropriate data for the connected communication, using distribution system standards such as MPEG-DASH, in situations where multiple short-range, medium-range, or long-range wireless communications are available both indoors and outdoors. This will allow users to freely select and switch in real time between decoding devices or display devices, such as displays installed indoors or outdoors, as well as their own terminals. Furthermore, decoding can be performed while switching between the decoding terminal and the display terminal based on the user's location information. This will make it possible to display map information on the wall or part of the ground of an adjacent building with a displayable device embedded, while traveling to a destination. It will also be possible to switch the bitrate of the received data based on the ease of access to the encoded data on the network, such as when the encoded data is cached on a server that can be accessed quickly from the receiving terminal, or copied to an edge server in the content delivery service.

[0379] [Scalable encoding] Regarding content switching, we will explain using a scalable stream compressed and encoded using the video encoding method described in each of the embodiments above, as shown in Figure 26. The server may have multiple streams with the same content but different qualities as individual streams, but it may also be configured to switch content by taking advantage of the characteristics of a temporally / spatially scalable stream realized by encoding it in layers, as shown in the figure. In other words, the decoding side can freely switch between decoding low-resolution and high-resolution content by deciding which layer to decode according to internal factors such as performance and external factors such as the state of the communication bandwidth. For example, if you want to watch the rest of a video that you were watching on your smartphone ex115 while traveling, on a device such as an internet TV when you get home, that device only needs to decode the same stream to different layers, thus reducing the burden on the server.

[0380] Furthermore, in addition to the configuration described above, in which pictures are encoded for each layer and an enhancement layer exists above the base layer to achieve scalability, the enhancement layer may include metadata based on statistical information of the image, and the decoding side may generate high-quality content by super-resolution the picture in the base layer based on the metadata. Super-resolution may refer to either an improvement in the signal-to-noise ratio at the same resolution or an increase in resolution. The metadata may include information for identifying linear or nonlinear filter coefficients used in the super-resolution process, or information for identifying parameter values ​​in the filtering process, machine learning, or least-squares operation used in the super-resolution process.

[0381] Alternatively, the picture may be divided into tiles or similar structures according to the meaning of objects within the image, and the decoding side may select tiles to decode, thereby decoding only a portion of the area. Furthermore, by storing the attributes of objects (people, cars, balls, etc.) and their positions within the image (coordinate positions within the same image, etc.) as metadata, the decoding side can identify the location of a desired object based on the metadata and determine the tile containing that object. For example, as shown in Figure 27, the metadata is stored using a data storage structure different from pixel data, such as the SEI message in HEVC. This metadata indicates, for example, the position, size, or color of the main object.

[0382] Furthermore, metadata may be stored in units consisting of multiple pictures, such as streams, sequences, or random access units. This allows the decryption side to obtain information such as the time when a specific person appears in the video, and by combining this with the picture-level information, it can identify the picture in which the object exists and the object's position within that picture.

[0383] [Web page optimization] Figure 28 shows an example of a web page display screen on a computer ex111, etc. Figure 29 shows an example of a web page display screen on a smartphone ex115, etc. As shown in Figures 28 and 29, a web page may contain multiple linked images, which are links to image content, and their appearance will differ depending on the viewing device. When multiple linked images are visible on the screen, the display device (decoder) will display still images or I-pictures from each content as linked images, display video such as a GIF animation using multiple still images or I-pictures, or receive only the base layer and decode and display the video, until the user explicitly selects a linked image, or until the linked image approaches the center of the screen or the entire linked image is within the screen.

[0384] When a linked image is selected by the user, the display device prioritizes decoding the base layer. If the HTML of the web page contains information indicating that the content is scalable, the display device may decode up to the enhancement layer. Furthermore, to ensure real-time performance, before selection or when bandwidth is very limited, the display device can decode and display only forward-referenced pictures (I-pictures, P-pictures, and B-pictures that only use forward references), thereby reducing the delay between the decoding time and display time of the first picture (the delay from the start of content decoding to the start of display). Alternatively, the display device may deliberately ignore the reference relationships between pictures and roughly decode all B-pictures and P-pictures using forward references, then perform normal decoding as time passes and more pictures are received.

[0385] [Autonomous driving] Furthermore, when transmitting and receiving still images or video data such as 2D or 3D map information for autonomous driving or driving assistance of a vehicle, the receiving terminal may receive metadata such as weather or construction information in addition to image data belonging to one or more layers, and decode these in association with each other. The metadata may belong to a layer, or it may simply be multiplexed with the image data.

[0386] In this case, since the vehicle, drone, or airplane containing the receiving terminal is in motion, the receiving terminal can transmit its location information when a reception request is made, enabling seamless reception and decoding while switching between base stations ex106 to ex110. Furthermore, the receiving terminal can dynamically switch how much metadata is received or how much map information is updated, depending on the user's selection, the user's situation, or the state of the communication bandwidth.

[0387] As described above, the content supply system ex100 allows the client to receive, decode, and play back encoded information transmitted by the user in real time.

[0388] [Distribution of personal content] Furthermore, the ex100 content delivery system allows for unicast or multicast distribution of not only high-definition, long-duration content from video distribution companies, but also low-definition, short-duration content from individuals. It is also expected that the amount of such individual content will continue to increase. To improve the quality of individual content, the server may perform editing before encoding. This can be achieved, for example, with the following configuration.

[0389] During shooting, or after shooting, the server performs recognition processing such as detecting shooting errors, searching for scenes, analyzing semantics, and detecting objects from the original images or encoded data in real time. Based on the recognition results, the server manually or automatically edits the images, correcting out-of-focus or shaky images, deleting less important scenes such as those with lower brightness or out of focus compared to other pictures, emphasizing object edges, and changing color tones. The server then encodes the edited data based on the editing results. It is also known that viewership decreases if the shooting time is too long, so the server may automatically clip scenes with little movement, as well as less important scenes, based on the image processing results, to ensure that the content falls within a specific time range according to the shooting time. Alternatively, the server may generate and encode a digest based on the results of the semantic analysis of the scenes.

[0390] Furthermore, personal content may contain elements that infringe on copyright, moral rights, or portrait rights, and the scope of sharing may exceed the intended scope, which can be inconvenient for the individual. Therefore, for example, the server may intentionally change the image to one that is out of focus, such as the faces of people at the edges of the screen or the interior of a house, before encoding. The server may also recognize whether the face of a person other than those previously registered is visible in the image to be encoded, and if so, it may apply a mosaic effect to the face. Alternatively, as a pre- or post-processing step before encoding, the user can specify a person or background area that they want to process from a copyright perspective, and the server can replace the specified area with a different image or blur the focus. In the case of a person, the server can track the person in a video and replace the image of their face.

[0391] Furthermore, because viewing personal content with small data volumes requires real-time processing, depending on the bandwidth, the decoder prioritizes receiving, decoding, and playing the base layer first. During this time, the decoder can receive the enhancement layer, and if playback is looped or if the content is played more than once, it may play the high-quality video including the enhancement layer. With a stream that uses this scalable encoding, it is possible to provide an experience where the video is rough when unselected or at the beginning of viewing, but gradually the stream becomes smarter and the image quality improves. In addition to scalable encoding, a similar experience can be provided even if the rough stream played the first time and the second stream encoded by referencing the first video are configured as a single stream.

[0392] [Other usage examples] Furthermore, these encoding or decoding processes are generally performed by the LSIex500 present in each terminal. The LSIex500 may be a single chip or a multi-chip configuration. Alternatively, video encoding or decoding software may be embedded in some recording medium (such as a CD-ROM, flexible disk, or hard disk) that can be read by a computer ex111, and the encoding or decoding process may be performed using that software. In addition, if the smartphone ex115 has a camera, video data acquired by that camera may be transmitted. In this case, the video data is data encoded by the LSIex500 present in the smartphone ex115.

[0393] The LSIex500 may also be configured to be activated by downloading application software. In this case, the terminal first determines whether it supports the content encoding method or whether it has the capability to perform the specific service. If the terminal does not support the content encoding method or does not have the capability to perform the specific service, the terminal downloads the codec or application software, and then acquires and plays the content.

[0394] Furthermore, not only the content supply system ex100 via the Internet ex101, but also digital broadcasting systems can incorporate at least one of the video encoding device (image encoding device) or video decoding device (image decoding device) of each of the above embodiments. While the content supply system ex100 has a configuration that is more suited to multicast than unicast, as it transmits and receives multiplexed data with video and sound multiplexed onto broadcast radio waves using satellites, etc., the encoding and decoding processes are similar and can be applied in the same way.

[0395] [Hardware configuration] Figure 30 shows the smartphone ex115. Figure 31 shows an example of the configuration of the smartphone ex115. The smartphone ex115 includes an antenna ex450 for transmitting and receiving radio waves with the base station ex110, a camera unit ex465 capable of taking video and still images, and a display unit ex458 that displays video captured by the camera unit ex465 and data decoded from video received by the antenna ex450. The smartphone ex115 further includes an operation unit ex466, such as a touch panel, an audio output unit ex457, such as a speaker for outputting voice or sound, an audio input unit ex456, such as a microphone for inputting voice, a memory unit ex467 capable of storing captured video or still images, recorded audio, received video or still images, encoded data such as emails, or decoded data, and a slot unit ex464, which is an interface unit with SIM ex468 for identifying the user and authenticating access to various data, including the network. External memory may be used instead of the memory unit ex467.

[0396] Furthermore, the main control unit ex460, which comprehensively controls the display unit ex458 and the operation unit ex466, is connected via the bus ex470 to the power supply circuit unit ex461, the operation input control unit ex462, the video signal processing unit ex455, the camera interface unit ex463, the display control unit ex459, the modulation / demodulation unit ex452, the multiplexing / decompression unit ex453, the audio signal processing unit ex454, the slot unit ex464, and the memory unit ex467.

[0397] The power supply circuit unit ex461, when the power key is turned on by the user, supplies power from the battery pack to each component, thereby starting up the smartphone ex115 and making it operational.

[0398] The smartphone ex115 performs tasks such as phone calls and data communication based on the control of the main control unit ex460, which has a CPU, ROM, RAM, etc. During a call, the audio signal picked up by the audio input unit ex456 is converted into a digital audio signal by the audio signal processing unit ex454, which is then subjected to spread spectrum processing by the modulation / demodulation unit ex452, and after digital-to-analog conversion and frequency conversion processing by the transmission / reception unit ex451, it is transmitted via the antenna ex450. Similarly, received data is amplified, subjected to frequency conversion and analog-to-digital conversion processing, despread spectrum processing by the modulation / demodulation unit ex452, converted into an analog audio signal by the audio signal processing unit ex454, and then output from the audio output unit ex457. In data communication mode, text, still images, or video data are sent to the main control unit ex460 via the operation input control unit ex462 by the operation unit ex466 of the main unit, and transmission and reception processing is performed in the same manner. When transmitting video, still images, or video and audio in data communication mode, the video signal processing unit ex455 compresses and encodes the video signal stored in the memory unit ex467 or the video signal input from the camera unit ex465 using the video encoding method shown in each of the above embodiments, and sends the encoded video data to the multiplexing / decoding unit ex453. The audio signal processing unit ex454 encodes the audio signal picked up by the audio input unit ex456 while the camera unit ex465 is capturing video or still images, and sends the encoded audio data to the multiplexing / decoding unit ex453. The multiplexing / decoding unit ex453 multiplexes the encoded video data and encoded audio data in a predetermined manner, performs modulation and conversion processing in the modulation / demodulation unit (modulation / demodulation circuit unit) ex452 and the transmission / reception unit ex451, and transmits the data via the antenna ex450.

[0399] When receiving video attached to an email or chat, or video linked to a webpage, etc., the multiplexing / decomposition unit ex453 separates the multiplexed data received via antenna ex450 to decode the multiplexed data, dividing it into a video data bitstream and an audio data bitstream. It then supplies the encoded video data to the video signal processing unit ex455 and the encoded audio data to the audio signal processing unit ex454 via the synchronization bus ex470. The video signal processing unit ex455 decodes the video signal using a video decoding method corresponding to the video encoding method shown in each embodiment above, and displays the video or still image contained in the linked video file from the display unit ex458 via the display control unit ex459. The audio signal processing unit ex454 decodes the audio signal, and audio is output from the audio output unit ex457. However, since real-time streaming is widespread, there may be situations where audio playback is socially inappropriate depending on the user's circumstances. Therefore, as an initial setting, it is preferable to have a configuration that plays only video data and not audio signals. Audio may be synchronized and played only when the user performs an action, such as clicking on video data.

[0400] Furthermore, although the smartphone ex115 was used as an example here, there are three possible implementation formats for terminals: a transceiver-type terminal that has both an encoder and a decoder, a transmitting terminal that has only an encoder, and a receiving terminal that has only a decoder. In addition, although it was explained that multiplexed data, in which audio data etc. is multiplexed with video data, is received or transmitted in a digital broadcasting system, the multiplexed data may also include text data related to the video in addition to audio data, or the video data itself may be received or transmitted instead of multiplexed data.

[0401] Although it was explained that the main control unit ex460, including the CPU, controls the encoding or decoding process, terminals often also have a GPU. Therefore, a configuration that leverages the GPU's performance to process a wide area at once using memory shared by the CPU and GPU, or memory whose addresses are managed so that it can be used in common, is also possible. This can shorten the encoding time, ensure real-time performance, and achieve low latency. In particular, it is efficient to perform motion detection, deblocking filters, SAO (Sample Adaptive Offset), and transformation / quantization processes at once on the GPU, rather than on the CPU, in units such as pictures.

[0402] This embodiment may be implemented in combination with at least some of the other embodiments of this disclosure. Furthermore, some of the processes, some of the configurations of the apparatus, some of the syntax, etc., described in the flowchart of this embodiment may be implemented in combination with the other embodiments. [Industrial applicability]

[0403] This disclosure can be used, for example, in television receivers, digital video recorders, car navigation systems, mobile phones, digital cameras, digital video cameras, video conferencing systems, or electronic mirrors. [Explanation of Symbols]

[0404] 100 Encoding device 102 Division 104 Subtraction Unit 106 Conversion Unit 108 Quantization section 110 Entropy coding unit 112, 204 Inverse quantization section 114, 206 Inverse Transform Section 116, 208 Addition section 118, 210 block memory 120, 212 Loop filter section 122,214 frame memory 124, 216 Intra Prediction Unit 126, 218 Interpretation Unit 128, 220 Prediction Control Unit 160, 260 circuits 162,262 memory 200 Decoders 202 Entropy Decoder

Claims

1. Circuits and, Equipped with memory, The circuit uses the memory to perform interpretation processing. Using the motion vectors of past processing blocks, the first motion vector of the first processing block is derived. By performing motion search processing on the region surrounding the first motion vector, the second motion vector of the first processing target block is derived. A predicted image of the first processing target block is generated by motion compensation using the second motion vector. If a second processing target block, which is a processing target block that occurs after the first processing target block, belongs to the same picture as the first processing target block, the third motion vector of the second processing target block is derived using the first motion vector of the first processing target block shown in the motion vector list. If the second processing target block belongs to a different picture than the first processing target block, the third motion vector of the second processing target block is derived using the second motion vector of the first processing target block shown in the motion vector list. By performing motion search processing on the region surrounding the third motion vector, the fourth motion vector of the second processing target block is derived. A predicted image of the second processing target block is generated by motion compensation using the fourth motion vector. The first motion vector is further used in loop filtering, Encoding device.

2. Circuits and, Equipped with memory, The circuit uses the memory to perform interpretation processing. Using the motion vectors of past processing blocks, the first motion vector of the first processing block is derived. By performing motion search processing on the region surrounding the first motion vector, the second motion vector of the first processing target block is derived. A predicted image of the first processing target block is generated by motion compensation using the second motion vector. If a second processing target block, which is a processing target block that occurs after the first processing target block, belongs to the same picture as the first processing target block, the third motion vector of the second processing target block is derived using the first motion vector of the first processing target block shown in the motion vector list. If the second processing target block belongs to a different picture than the first processing target block, the third motion vector of the second processing target block is derived using the second motion vector of the first processing target block shown in the motion vector list. By performing motion search processing on the region surrounding the third motion vector, the fourth motion vector of the second processing target block is derived. A predicted image of the second processing target block is generated by motion compensation using the fourth motion vector. The first motion vector is further used in loop filtering, Decoding device.

3. Using the motion vectors of past processing blocks, the first motion vector of the first processing block is derived. By performing motion search processing on the region surrounding the first motion vector, the second motion vector of the first processing target block is derived. A predicted image of the first processing target block is generated by motion compensation using the second motion vector. If a second processing target block, which is a processing target block that occurs after the first processing target block, belongs to the same picture as the first processing target block, the third motion vector of the second processing target block is derived using the first motion vector of the first processing target block shown in the motion vector list. If the second processing target block belongs to a different picture than the first processing target block, the third motion vector of the second processing target block is derived using the second motion vector of the first processing target block shown in the motion vector list. By performing motion search processing on the region surrounding the third motion vector, the fourth motion vector of the second processing target block is derived. A predicted image of the second processing target block is generated by motion compensation using the fourth motion vector. Generate a bitstream containing information for performing interpretation processing. The bitstream is transmitted, The first motion vector is further used in loop filtering, How to send a bitstream.

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