Geometric partitioning scheme with simplified motion field storage and motion compensation in video codecs

Abstract

A video decoder may be configured to: for a block of video data encoded in a geometric partitioning mode, determine an angle for the block in the geometric partitioning mode; determine a separation line displacement relative to a center of the block in the geometric partitioning mode; partition the block into a first partition and a second partition based on the angle and the separation line displacement; determine a first prediction sample of the block using a motion vector of the first partition, and determine a second prediction sample of the block using a motion vector of the second partition; determine a power of 2 based on the angle of the block; determine a weight value based on the power of 2; and perform a blending operation on the first prediction sample and the second prediction sample based on the weight value to determine a prediction block for the block.

Description

[0001] This application claims priority to U.S. Application No. 17 / 028,517, filed September 22, 2020, which claims the benefit of:

[0002] U.S. Provisional Patent Application No. 62 / 904,566, filed September 23, 2019; and

[0003] U.S. Provisional Patent Application No. 62 / 905,276, filed September 24, 2019,

[0004] The entire contents of each of the above applications are incorporated herein by reference. Technical Field

[0005] The present disclosure relates to video encoding and video decoding. Background Art

[0006] Digital video capabilities can be incorporated into a wide range of devices, including digital televisions, digital direct broadcast systems, wireless broadcast systems, personal digital assistants (PDAs), laptop or desktop computers, tablet computers, e-book readers, digital cameras, digital recording devices, digital media players, video game devices, video game consoles, cellular or satellite radio telephones, so-called "smart phones", video teleconferencing devices, video streaming devices, etc. Digital video devices implement video coding technologies such as those described in the standards defined by MPEG-2, MPEG-4, ITU-T H.263, ITU-T H.264 / MPEG-4 Part 10, Advanced Video Codec (AVC), ITU-T H.265 / High Efficiency Video Codec (HEVC), and extensions of such standards. By implementing such video coding technologies, video devices can more efficiently transmit, receive, encode, decode, and / or store digital video information.

[0007] Video coding techniques include spatial (intra-picture) prediction and / or temporal (inter-picture) prediction to reduce or remove redundancy inherent in video sequences. For block-based video coding, a video slice (e.g., a video picture or a portion of a video picture) can be partitioned into video blocks, which can also be referred to as coding tree units (CTUs), coding units (CUs), and / or coding nodes. Video blocks in an intra-coded (I) slice of a picture are encoded using spatial prediction relative to reference samples in neighboring blocks in the same picture. Video blocks in an inter-coded (P or B) slice of a picture can use spatial prediction relative to reference samples in neighboring blocks in the same picture, or temporal prediction relative to reference samples in other reference pictures. Pictures can be referred to as frames, and reference pictures can be referred to as reference frames. Summary of the Invention

[0008] In general, this disclosure describes techniques for reducing the complexity of inter-frame prediction, such as by simplifying the storage of geometric partition mode (GEO) codecs. In this way, the example techniques can provide a technical solution to a technical problem with practical application to improve the operation of a video codec (e.g., a video encoder or a video decoder).

[0009] In one example of the present disclosure, a method includes: determining that a block of video data is encoded in a geometric partitioning mode; determining an angle of the block of video data for the geometric partitioning mode; determining a separation line displacement relative to a center of the block of the geometric partitioning mode; partitioning the block into a first partition and a second partition based on the angle and the separation line displacement; determining a first prediction sample of the block of video data using a motion vector of the first partition; determining a second prediction sample of the block of video data using a motion vector of the second partition; determining a power of 2 based on the angle of the block of video data; determining a weight value based on the power of 2; performing a blending operation on the first prediction sample and the second prediction sample based on the weight value to determine a prediction block for the block of video data; and outputting the prediction block.

[0010] In another example of the present disclosure, a device for decoding video data includes: a memory configured to store video data; and one or more processors implemented in circuitry and configured to: determine that a block of video data is encoded in a geometric partitioning mode; determine an angle of the block of video data for the geometric partitioning mode; determine a separation line displacement relative to a center of the block of the geometric partitioning mode; divide the block into a first partition and a second partition based on the angle and the separation line displacement; determine a first prediction sample of the block of video data using a motion vector of the first partition; determine a second prediction sample of the block of video data using a motion vector of the second partition; determine a power of 2 based on the angle of the block of video data; determine a weight value based on the power of 2; perform a blending operation on the first prediction sample and the second prediction sample based on the weight value to determine a prediction block for the block of video data; and output the prediction block.

[0011] In another example of the present disclosure, an apparatus for decoding video data includes: a component for determining that a block of video data is encoded in a geometric partitioning mode; a component for determining an angle of the block of video data for the geometric partitioning mode; a component for determining a separation line displacement relative to a center of the block of the geometric partitioning mode; a component for partitioning the block into a first partition and a second partition based on the angle and the separation line displacement; a component for determining a first prediction sample of the block of video data using a motion vector of the first partition; a component for determining a second prediction sample of the block of video data using a motion vector of the second partition; a component for determining a power of 2 based on the angle of the block of video data; a component for determining a weight value based on the power of 2; a component for performing a blending operation on the first prediction sample and the second prediction sample based on the weight value to determine a prediction block for the block of video data; and a component for outputting the prediction block.

[0012] In another example of the present disclosure, a computer-readable storage medium stores instructions that, when executed by one or more processors, cause the one or more processors to: determine that a block of video data is encoded in a geometric partitioning mode; determine an angle for the block of video data in the geometric partitioning mode; determine a separation line displacement relative to a center of the block in the geometric partitioning mode; partition the block into a first partition and a second partition based on the angle and the separation line displacement; determine a first prediction sample for the block of video data using a motion vector of the first partition; determine a second prediction sample for the block of video data using a motion vector of the second partition; determine a power of 2 based on the angle of the block of video data; determine a weight value based on the power of 2; perform a blending operation on the first prediction sample and the second prediction sample based on the weight value to determine a prediction block for the block of video data; and output the prediction block.

[0013] The details of one or more examples are set forth in the accompanying drawings and the description below. Other features, objects, and advantages will be apparent from the description, drawings, and claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 is a block diagram illustrating an example video encoding and decoding system that may perform the techniques of this disclosure.

[0015] Figure 2A and Figure 2B is a conceptual diagram illustrating an example quadtree binary tree (QTBT) structure and a corresponding codec tree unit (CTU).

[0016] Figure 3 is a block diagram illustrating an example video encoder that may perform the techniques of this disclosure.

[0017] Figure 4 is a block diagram illustrating an example video decoder that may perform the techniques of this disclosure.

[0018] Figure 5A and Figure 5B are conceptual diagrams illustrating examples of triangle partitioning based on diagonal partitioning and anti-diagonal partitioning, respectively, for inter-frame prediction.

[0019] Figure 6 is a conceptual diagram illustrating an example of spatially and temporally neighboring blocks used to construct a candidate list.

[0020] Figure 7 is a table showing motion vector prediction selection for triangle partitioning mode.

[0021] Figure 8A and Figure 8B 2 are conceptual diagrams illustrating weights for the mixing process of luma components and chroma components, respectively.

[0022] Figure 9 is a conceptual diagram illustrating an example of a triangle partition mode (TPM) applied to a geometric partition mode (GEO).

[0023] Figure 10 is a conceptual diagram illustrating an example of GEO segmentation signaling.

[0024] Figure 11A and Figure 11B is a conceptual diagram showing the geometric relationship between segmentation edges, displacements, and angles.

[0025] Figure 12 is a conceptual diagram showing an example of projecting a point E at (x, y) onto an edge En.

[0026] Figure 13is a conceptual diagram illustrating an example of partial transformation of an inter-prediction block for GEO prediction.

[0027] Figure 14 is a conceptual diagram illustrating an example of deblocking-like processing of a partial transform.

[0028] Figure 15 is a table showing an example of GEO weights using angles in a ratio of 2:1.

[0029] Figure 16 is a table showing the angles removed to reduce the number of partitions.

[0030] Figure 17 is a flow chart illustrating an example method for encoding a current block of video data.

[0031] Figure 18 is a flow chart illustrating an example method for decoding a current block of video data.

[0032] Figure 19A is a conceptual diagram showing edges supported in GEO with respect to the current coding unit (CU).

[0033] Figure 19B is a conceptual diagram showing the geometric relationship between a given pixel position (x, y) and two edges.

[0034] Figure 20 is a conceptual diagram illustrating example angles of a GEO and their corresponding aspect ratios according to one embodiment.

[0035] Figure 21 is a flow diagram illustrating example operations for decoding video data, in accordance with one or more techniques of this disclosure. DETAILED DESCRIPTION

[0036] Video codecs (e.g., video encoding and / or video decoding) typically involve predicting blocks of video data from blocks of coded video data in the same picture (e.g., intra-frame prediction) or blocks of coded video data in different pictures (e.g., inter-frame prediction). In some cases, the video encoder also calculates residual data by comparing the predicted block to the original block. Thus, the residual data represents the difference between the predicted block and the original block. To reduce the number of bits required to signal the residual data, the video encoder transforms and quantizes the residual data and sends the transformed and quantized residual data in the coded bitstream. The compression achieved by the transform and quantization process may be lossy, which means that the transform and quantization process may introduce distortion in the decoded video data.

[0037] The video decoder decodes the residual data and adds it to the predicted block to produce a reconstructed video block that more closely matches the original video block than the predicted block alone. Due to losses introduced by the transformation and quantization of the residual data, the reconstructed block may have distortion or artifacts. A common artifact or distortion is called blockiness, in which the boundaries of the blocks used to encode and decode the video data are visible.

[0038] To further improve the quality of the decoded video, the video decoder can perform one or more filtering operations on the reconstructed video blocks. Examples of these filtering operations include deblocking filtering, sample adaptive offset (SAO) filtering, and adaptive loop filtering (ALF). The parameters of these filtering operations can be determined by the video encoder and explicitly signaled in the coded video bitstream, or can be implicitly determined by the video decoder without the need for explicit signaling of the parameters in the coded video bitstream.

[0039] This disclosure describes techniques related to prediction, and more specifically, techniques related to predicting blocks of video data encoded in a geometric partitioning mode. For blocks encoded in a geometric partitioning mode, the video codec partitions the block into two partitions along a diagonal partitioning line. The size and location of the partitions are defined by the angle of the partitioning line and the displacement distance of the partitioning line from the center of the block. The video codec predicts the block by locating a first prediction sample using the motion vector of the first partition and a second prediction sample using the motion vector of the second partition. For prediction samples near the partitioning line, the video codec determines a final prediction value by taking a weighted average of the samples in the first prediction sample and the samples in the second prediction sample. For prediction samples that are greater than a certain distance from the partitioning line, the video codec may set the final prediction value of the prediction block to the sample value of the first prediction sample or the sample value of the second prediction sample, depending on whether the sample of the final prediction block is located in the first partition or the second partition. In some implementations, the video codec may still use a weighted average to set the final prediction value of the prediction block to the sample value of the first prediction sample or the sample value of the second prediction sample, but with weights of (1 and 0) or (0 and 1).

[0040] As will be explained in more detail, for each sample point near the dividing line, a weight value is determined as a function of the distance of the sample point from the dividing line. To calculate this distance, the video codec must typically be configured to perform sine and cosine calculations, which are computationally complex. However, according to the techniques of the present disclosure, the video codec can be configured to determine the angle of a block of video data encoded in a geometric partitioning mode, and based on this angle determine a power of 2, for example, equal to 2 nWhere n is an integer value, and the weight values are determined based on powers of 2. Determining the weight values based on powers of 2 reduces the number of sine and cosine calculations required to determine the weight values. For example, instead of the complex multiplication and division operations required for the sine and cosine calculations, the video codec can multiply by powers of 2 by applying a shift operation based on powers of 2. Since this calculation is performed for multiple samples of each block, the reduction in computational complexity can be significant. The disclosed techniques therefore have the advantage of reducing the computational complexity required by the video codec to determine weight values when encoding and decoding blocks in a geometric partitioning mode.

[0041] As used in this disclosure, the term video codec refers generally to video encoding or video decoding. Similarly, the term video codec may refer generally to a video encoder or a video decoder. In addition, certain techniques described in this disclosure with respect to video decoding may also be applied to video encoding, and vice versa. For example, typically, a video encoder and a video decoder are configured to perform the same process, or interacting processes. In addition, a video encoder typically performs video decoding (also known as reconstruction) as part of the process of determining how to encode video data. For example, a video encoder may perform deblocking filtering on decoded video blocks to determine whether a particular coding scheme produces a desired rate-distortion tradeoff, and also so that the video encoder can perform motion estimation using the same blocks available to the video decoder when the video decoder performs motion compensation.

[0042] Figure 1 1 is a block diagram illustrating an example video encoding and decoding system 100 that can perform the techniques of the present disclosure. The techniques of the present disclosure are generally directed to encoding and decoding (encoding and / or decoding) video data. Generally speaking, video data includes any data used to process video. Thus, video data can include original unencoded video, encoded video, decoded (e.g., reconstructed) video, and video metadata (such as signaling data).

[0043] like Figure 1 As shown in , in this example, system 100 includes a source device 102 that provides encoded video data to be decoded and displayed by a destination device 116. In particular, source device 102 provides the video data to destination device 116 via a computer-readable medium 110. Source device 102 and destination device 116 may include any of a wide range of devices, including desktop computers, notebook (i.e., laptop) computers, mobile devices, tablet computers, set-top boxes, telephone handsets (such as smartphones), televisions, cameras, display devices, digital media players, video game consoles, video streaming devices, broadcast receiver devices, etc. In some cases, source device 102 and destination device 116 may be equipped for wireless communication and, therefore, may be referred to as wireless communication devices.

[0044] exist Figure 1 In the example of , source device 102 includes a video source 104, a memory 106, a video encoder 200, and an output interface 108. Destination device 116 includes an input interface 122, a video decoder 300, a memory 120, and a display device 118. According to the present disclosure, the video encoder 200 of source device 102 and the video decoder 300 of destination device 116 can be configured to apply techniques for predicting blocks encoded and decoded in a geometric partitioning mode. Thus, source device 102 represents an example of a video encoding device, while destination device 116 represents an example of a video decoding device. In other examples, the source device and destination device can include other components or arrangements. For example, source device 102 can receive video data from an external video source such as an external camera. Similarly, destination device 116 can be connected to an external display device rather than including an integrated display device.

[0045] like Figure 1 The system 100 shown in is merely an example. In general, any digital video encoding and / or decoding device can perform techniques for predicting blocks encoded and decoded in a geometric partitioning pattern. The source device 102 and the destination device 116 are merely examples of such codec devices, wherein the source device 102 generates encoded and decoded video data for transmission to the destination device 116. This disclosure refers to a "codec" device as a device that performs encoding and decoding (encoding and / or decoding) of data. Therefore, the video encoder 200 and the video decoder 300 represent examples of codec devices, specifically, a video codec and a video decoder, respectively. In some examples, the source device 102 and the destination device 116 can operate in a generally symmetrical manner, such that each of the source device 102 and the destination device 116 includes video encoding and decoding components. Therefore, the system 100 can support one-way or two-way video transmission between the source device 102 and the destination device 116, for example, for video streaming, video playback, video broadcasting, or video telephony.

[0046] In general, video source 104 represents a source of video data (i.e., original, unencoded video data) and provides a continuous series of pictures (also referred to as "frames") of video data to video encoder 200, which encodes the picture data. Video source 104 of source device 102 may include a video capture device, such as a camera, a video archive containing previously captured raw video, and / or a video feed interface that receives video from a video content provider. As a further alternative, video source 104 may generate computer graphics-based data as the source video, or a combination of live video, archived video, and computer-generated video. In each case, video encoder 200 encodes captured, pre-captured, or computer-generated video data. Video encoder 200 may rearrange the pictures from the order in which they were received (sometimes referred to as "display order") into a codec order for encoding and decoding. Video encoder 200 may generate a bitstream comprising the video data to be encoded. Source device 102 may then output the encoded video data onto computer-readable medium 110 via output interface 108 for receipt and / or retrieval by, for example, input interface 122 of destination device 116 .

[0047] Memory 106 of source device 102 and memory 120 of destination device 116 represent general purpose memory. In some examples, memories 106 and 120 can store raw video data, e.g., raw video from video source 104 and raw decoded video data from video decoder 300. Additionally or alternatively, memories 106 and 120 can store software instructions executable by, for example, video encoder 200 and video decoder 300, respectively. Although memory 106 and memory 120 are shown separately from video encoder 200 and video decoder 300 in this example, it should be understood that video encoder 200 and video decoder 300 may also include internal memory for functionally similar or equivalent purposes. Furthermore, memories 106 and 120 can store, for example, video data to be encoded, output from video encoder 200 and input to video decoder 300. In some examples, portions of memories 106 and 120 can be allocated as one or more video buffers, e.g., to store raw, decoded, and / or encoded video data.

[0048] The computer-readable medium 110 can represent any type of medium or device capable of transmitting the encoded video data from the source device 102 to the destination device 116. In one example, the computer-readable medium 110 represents a communication medium that enables the source device 102 to send the encoded video data directly to the destination device 116 in real time, for example, via a radio frequency network or a computer-based network. According to a communication standard such as a wireless communication protocol, the output interface 108 can modulate a transmission signal including the encoded video data, and the input interface 122 can demodulate the received transmission signal. The communication medium can include any wireless or wired communication medium, such as a radio frequency (RF) spectrum or one or more physical transmission lines. The communication medium can form part of a packet-based network (such as a local area network, a wide area network, or a global network such as the Internet). The communication medium can include routers, switches, base stations, or any other equipment that helps facilitate communication from the source device 102 to the destination device 116.

[0049] In some examples, source device 102 may output the encoded data from output interface 108 to storage device 112. Similarly, destination device 116 may access the encoded data from storage device 112 via input interface 122. Storage device 112 may include any of a variety of distributed or locally accessed data storage media, such as a hard drive, Blu-ray disc, DVD, CD-ROM, flash memory, volatile or non-volatile memory, or any other suitable digital storage medium for storing encoded video data.

[0050] In some examples, source device 102 may output the encoded video data to file server 114 or another intermediate storage device that may store the encoded video data generated by source device 102. Destination device 116 may access the stored video data from file server 114 via streaming or downloading.

[0051] The file server 114 may be any type of server device capable of storing encoded video data and sending the encoded video data to the destination device 116. The file server 114 may represent, for example, a web server (for a website), a server configured to provide file transfer protocol services (such as the File Transfer Protocol (FTP) or the File Delivery over Unidirectional Transport (FLUET) protocol), a content delivery network (CDN) device, a hypertext transfer protocol (HTTP) server, a Multimedia Broadcast Multicast Service (MBMS) or an Enhanced MBMS (eMBMS) server, and / or a network attached storage (NAS) device. Additionally or alternatively, the file server 114 may implement one or more HTTP streaming protocols, such as Dynamic Adaptive Streaming over HTTP (DASH), HTTP Live Streaming (HLS), Real Time Streaming Protocol (RTSP), HTTP Dynamic Streaming, and the like.

[0052] Destination device 116 can access the encoded video data from file server 114 through any standard data connection, including an Internet connection. This can include a wireless channel (e.g., a Wi-Fi connection), a wired connection (e.g., a digital subscriber line (DSL), a cable modem, etc.), or a combination of both, suitable for accessing encoded video data stored on file server 114. Input interface 122 can be configured to operate according to any one or more of the various protocols discussed above for retrieving or receiving media data from file server 114, or other such protocols for retrieving media data.

[0053] Output interface 108 and input interface 122 may represent wireless transmitters / receivers, modems, wired network components (e.g., Ethernet cards), wireless communication components operating according to any of the various IEEE 802.1 standards, or other physical components. In examples where output interface 108 and input interface 122 include wireless components, output interface 108 and input interface 122 may be configured to transmit data, such as encoded video data, according to a cellular communication standard such as 4G, 4G-LTE (Long-Term Evolution), LTE Advanced, 5G, or some other wireless communication standard. In some examples where output interface 108 includes a wireless transmitter, output interface 108 and input interface 122 may be configured to transmit data, such as encoded video data, according to a cellular communication standard such as IEEE 802.11 specifications, IEEE 802.15 specifications (e.g., ZigBee TM ),Bluetooth TM The source device 102 and / or the destination device 116 may each include a system-on-a-chip (SoC) device. For example, the source device 102 may include a SoC device that performs the functionality attributed to the video encoder 200 and / or the output interface 108, and the destination device 116 may include a SoC device that performs the functionality attributed to the video decoder 300 and / or the input interface 122.

[0054] The techniques of the present disclosure can be applied to video encoding and decoding to support any of a variety of multimedia applications, such as over-the-air television broadcasting, cable television transmission, satellite television transmission, Internet streaming video transmission (such as, Dynamic Adaptive Streaming over HTTP (DASH)), digital video encoded onto a data storage medium, decoding of digital video stored on a data storage medium, or other applications.

[0055] The input interface 122 of the destination device 116 receives an encoded video bitstream from the computer-readable medium 110 (e.g., a communication medium, a storage device 112, a file server 114, etc.). The encoded video bitstream may include signaling information defined by the video encoder 200, such as syntax elements with values describing characteristics and / or processing of video blocks or other codec units (e.g., slices, pictures, groups of pictures, sequences, etc.), which is also used by the video decoder 300. The display device 118 displays decoded pictures of the decoded video data to a user. The display device 118 may represent any of a variety of display devices, such as a liquid crystal display (LCD), a plasma display, an organic light emitting diode (OLED) display, or another type of display device.

[0056] Although not in Figure 1 , but in some examples, the video encoder 200 and the video decoder 300 may each be integrated with an audio encoder and / or an audio decoder and may include appropriate MUX-DEMUX units or other hardware and / or software to process the multiplexed stream including both audio and video in a common data stream. If applicable, the MUX-DEMUX unit may conform to the ITU H.223 multiplexer protocol, or other protocols such as the User Datagram Protocol (UDP).

[0057] The video encoder 200 and the video decoder 300 can each be implemented as any of a variety of suitable encoder and / or decoder circuits, such as one or more microprocessors, digital signal processors (DSPs), application specific integrated circuits (ASICs), field programmable gate arrays (FPGAs), discrete logic, software, hardware, firmware, or any combination thereof. When the technology is partially implemented in software, the device can store instructions for the software in a suitable non-transitory computer-readable medium and use one or more processors to execute the instructions in hardware to perform the technology of the present disclosure. Each of the video encoder 200 and the video decoder 300 can be included in one or more encoders or decoders, any of which can be integrated as part of a combined encoder / decoder (CODEC) in the corresponding device. The device including the video encoder 200 and / or the video decoder 300 can include an integrated circuit, a microprocessor, and / or a wireless communication device such as a cellular phone.

[0058] The video encoder 200 and the video decoder 300 may operate in accordance with a video codec standard such as ITU-T H.265 (also known as High Efficiency Video Coding (HEVC)) or its extensions (such as multi-view and / or scalable video codec extensions). Alternatively, the video encoder 200 and the video decoder 300 may operate in accordance with other proprietary or industry standards such as ITU-T H.266 (also known as Versatile Video Coding (VVC)). A draft of the VVC standard is described in Bross et al., “Versatile Video Coding (Draft 6)” (ITU-T SG 16WP 3 and ISO / IEC JTC 1 / SC 29 / WG 11 Joint Video Experts Group (JVET), 15th Meeting: Gothenburg, Sweden, July 3-12, 2019, JVET-O2001-vE) (hereinafter referred to as “VVC Draft 6”). Another draft of the VVC standard is described in Bross et al., "Versatile Video Coding (Draft 10)" (ITU-T SG 16 WP 3 and ISO / IEC JTC 1 / SC29 / WG 11 Joint Video Experts Group (JVET) 18th Meeting: by teleconference, June 22-July 1, 2020, JVET-S2001-vA) (hereinafter referred to as "VVC Draft 10"). However, the techniques of this disclosure are not limited to any particular codec standard.

[0059] Generally speaking, the video encoder 200 and the video decoder 300 can perform block-based encoding and decoding of pictures. The term "block" generally refers to a structure that includes data to be processed (e.g., data that is encoded, decoded, or otherwise used in an encoding and / or decoding process). For example, a block can include a two-dimensional matrix of samples of luma and / or chroma data. Generally speaking, the video encoder 200 and the video decoder 300 can encode and decode video data represented in a YUV (e.g., Y, Cb, Cr) format. That is, rather than encoding and decoding red, green, and blue (RGB) data of samples of a picture, the video encoder 200 and the video decoder 300 can encode and decode luma and chroma components, where the chroma components may include both red and blue hue chroma components. In some examples, the video encoder 200 converts the received RGB formatted data into a YUV representation before encoding, and the video decoder 300 converts the YUV representation into an RGB format. Alternatively, pre-processing and post-processing units (not shown) can perform these conversions.

[0060] The present disclosure may generally relate to the encoding and decoding of pictures (e.g., encoding and decoding), to include the process of encoding or decoding picture data. Similarly, the present disclosure may relate to the encoding and decoding of blocks of pictures, to include the process of encoding or decoding the data of the blocks, for example, prediction and / or residual encoding and decoding. A coded video bitstream typically includes a series of values of syntax elements used to represent codec decisions (e.g., codec mode) and the partitioning of pictures into blocks. Therefore, references to encoding and decoding a picture or block should generally be understood as encoding and decoding the values of the syntax elements used to form the picture or block.

[0061] HEVC defines various blocks, including coding units (CUs), prediction units (PUs), and transform units (TUs). According to HEVC, a video codec (such as the video encoder 200) partitions a codec tree unit (CTU) into CUs according to a quadtree structure. That is, the video codec partitions the CTU and CU into four equal, non-overlapping squares, and each node of the quadtree has zero or four child nodes. A node without child nodes may be referred to as a "leaf node," and the CU of such a leaf node may include one or more PUs and / or one or more TUs. The video codec may also partition PUs and TUs. For example, in HEVC, a residual quadtree (RQT) represents the partitioning of a TU. In HEVC, a PU represents inter-frame prediction data, and a TU represents residual data. An intra-predicted CU includes intra-frame prediction information, such as an intra-frame mode indication.

[0062] As another example, the video encoder 200 and the video decoder 300 can be configured to operate according to VVC. According to VVC, a video codec (such as the video encoder 200) partitions a picture into multiple codec tree units (CTUs). The video encoder 200 can partition the CTU according to a tree structure, such as a quadtree-binary tree (QTBT) structure or a multi-type tree (MTT) structure. The QTBT structure removes the concept of multiple partition types, such as the distinction between CU, PU, and TU of HEVC. The QTBT structure includes two levels: a first level partitioned according to quadtree partitioning, and a second level partitioned according to binary tree partitioning. The root node of the QTBT structure corresponds to the CTU. The leaf nodes of the binary tree correspond to the codec units (CUs).

[0063] In the MTT partitioning structure, blocks can be partitioned using quadtree (QT) partitioning, binary tree (BT) partitioning, and one or more types of triple tree (TT) (also known as ternary tree) partitioning. Triple or ternary tree partitioning is a partitioning that divides a block into three sub-blocks. In some examples, triple or ternary tree partitioning divides a block into three sub-blocks without partitioning the original block through the center. The partitioning types in MTT (e.g., QT, BT, and TT) can be symmetric or asymmetric.

[0064] In some examples, the video encoder 200 and the video decoder 300 may use a single QTBT or MTT structure to represent each of the luma component and the chroma components, while in other examples, the video encoder 200 and the video decoder 300 may use two or more QTBT or MTT structures, such as one QTBT / MTT structure for the luma component and another QTBT / MTT structure for the two chroma components (or two QTBT / MTT structures for corresponding chroma components).

[0065] The video encoder 200 and the video decoder 300 can be configured to use quadtree segmentation, QTBT segmentation, MTT segmentation, or other segmentation structures in accordance with HEVC. For the purpose of explanation, the description of the technology of the present disclosure is presented with respect to QTBT segmentation. However, it should be understood that the technology of the present disclosure can also be applied to video codecs configured to use quadtree segmentation or other types of segmentation.

[0066] In some examples, a CTU includes a codec tree block (CTB) of luma samples, two corresponding CTBs of chroma samples for a picture with three sample arrays, or a CTB of samples for a monochrome picture, or a picture coded and decoded using three separate color planes and syntax structures for codec samples. A CTB can be an NxN block of samples for some value of N, such that partitioning a component into CTBs is a partitioning. A component is one of the three arrays (luma and two chroma) or a single sample from one of the three arrays that make up a picture in 4:2:0, 4:2:2, or 4:4:4 color format, or an array or a single sample of an array that makes up a picture in monochrome format. In some examples, a codec block is an MxN block of samples for some values of M and N, such that partitioning a CTB into codec blocks is a partitioning.

[0067] These blocks (e.g., CTUs or CUs) can be grouped in various ways in a picture. As an example, a brick can refer to a rectangular area of a CTU row within a particular tile in a picture. A tile can be a rectangular area of a CTU within a particular tile column and a particular tile row in a picture. A tile column refers to a rectangular area of a CTU with a height equal to the height of the picture and a width specified by a syntax element (e.g., such as in a picture parameter set). A tile row refers to a rectangular area of a CTU with a height specified by a syntax element (e.g., such as in a picture parameter set) and a width equal to the width of the picture.

[0068] In some examples, a tile may be partitioned into multiple blocks, each of which may include one or more CTU rows within the tile. A tile that is not partitioned into multiple blocks may also be referred to as a tile. However, a block that is a true subset of a tile may not be referred to as a tile.

[0069] The tiles in a picture can also be arranged in slices. A slice can be an integer number of tiles of a picture that can be contained exclusively in a single network abstraction layer (NAL) unit. In some examples, a slice includes a contiguous sequence of multiple complete tiles or just complete tiles of a single tile.

[0070] This disclosure uses "NxN" and "N by N" interchangeably to refer to the sample dimensions of a block (such as a CU or other video block) in terms of the vertical and horizontal dimensions, for example, 16x16 samples or 16 by 16 samples. In general, a 16x16 CU will have 16 samples in the vertical direction (y=16) and 16 samples in the horizontal direction (x=16). Similarly, an NxN CU typically has N samples in the vertical direction and N samples in the horizontal direction, where N represents a non-negative integer value. The samples in a CU may be arranged in rows and columns. Furthermore, a CU does not necessarily need to have the same number of samples in the horizontal direction as in the vertical direction. For example, a CU may include NxM samples, where M is not necessarily equal to N.

[0071] The video encoder 200 encodes video data representing prediction and / or residual information and other information for a CU. The prediction information indicates how the CU will be predicted to form a prediction block for the CU. The residual information typically represents the sample-by-sample difference between the samples of the CU before encoding and the prediction block.

[0072] To predict a CU, the video encoder 200 may typically form a prediction block for the CU through inter-frame prediction or intra-frame prediction. Inter-frame prediction typically refers to predicting a CU from data of a previously coded picture, while intra-frame prediction typically refers to predicting a CU from previously coded data of the same picture. To perform inter-frame prediction, the video encoder 200 may use one or more motion vectors to generate a prediction block. The video encoder 200 may typically perform a motion search to identify a reference block that closely matches the CU, for example, based on the difference between the CU and the reference block. The video encoder 200 may use the sum of absolute differences (SAD), the sum of squared differences (SSD), the mean absolute difference (MAD), the mean squared difference (MSD), or other such difference calculations to calculate a difference metric to determine whether the reference block closely matches the current CU. In some examples, the video encoder 200 may use unidirectional prediction or bidirectional prediction to predict the current CU.

[0073] Some examples of VVC also provide an affine motion compensation mode, which can be considered an inter-frame prediction mode. In affine motion compensation mode, the video encoder 200 can determine two or more motion vectors representing non-translational motion such as: zooming in or out, rotation, perspective motion, or other irregular motion types.

[0074] To perform intra prediction, the video encoder 200 can select an intra prediction mode to generate a prediction block. Some examples of VVC provide sixty-seven intra prediction modes, including various directional modes, as well as a planar mode and a DC mode. In general, the video encoder 200 selects the following intra prediction modes: neighboring samples describing a current block (e.g., a block of a CU) to predict the samples of the current block. Assuming that the video encoder 200 encodes and decodes CTUs and CUs in raster scan order (from left to right, from top to bottom), such samples can typically be located above, above and to the left of, or to the left of the current block in the same picture as the current block.

[0075] The video encoder 200 encodes data indicating the prediction mode for the current block. For example, for inter-frame prediction mode, the video encoder 200 may encode data indicating which of various available inter-frame prediction modes to use, as well as motion information for the corresponding mode. For example, for unidirectional or bidirectional inter-frame prediction, the video encoder 200 may encode motion vectors using advanced motion vector prediction (AMVP) or merge mode. For affine motion compensation mode, the video encoder 200 may use a similar mode to encode motion vectors.

[0076] After predicting a block, such as after intra-frame prediction or inter-frame prediction of the block, the video encoder 200 can calculate residual data for the block. The residual data, such as a residual block, represents the sample-by-sample difference between the block and a prediction block for the block formed using the corresponding prediction mode. The video encoder 200 can apply one or more transforms to the residual block to produce transformed data in a transform domain rather than a sample domain. For example, the video encoder 200 can apply a discrete cosine transform (DCT), an integer transform, a wavelet transform, or a conceptually similar transform to the residual video data. Additionally, the video encoder 200 can apply a secondary transform, such as a mode-dependent non-separable secondary transform (MDNSST), a signal-dependent transform, a Karhunen-Loeve transform (KLT), etc., after the primary transform. The video encoder 200 produces transform coefficients after applying one or more transforms.

[0077] As described above, after any transform used to generate transform coefficients, the video encoder 200 can perform quantization on the transform coefficients. Quantization generally refers to the process of quantizing transform coefficients to potentially reduce the amount of data used to represent the transform coefficients, thereby providing further compression. By performing the quantization process, the video encoder 200 can reduce the bit depth associated with some or all of the transform coefficients. For example, the video encoder 200 can round down an n-bit value to an m-bit value during quantization, where n is greater than m. In some examples, to perform quantization, the video encoder 200 can perform a bit-by-bit right shift of the value to be quantized.

[0078] After quantization, the video encoder 200 may scan the transform coefficients to produce a one-dimensional vector from a two-dimensional matrix including the quantized transform coefficients. The scan may be designed to place higher energy (and therefore lower frequency) transform coefficients at the front of the vector and lower energy (and therefore higher frequency) transform coefficients at the back of the vector. In some examples, the video encoder 200 may scan the quantized transform coefficients using a predefined scan order to produce a serialized vector and then entropy encode the quantized transform coefficients of the vector. In other examples, the video encoder 200 may perform adaptive scanning. After scanning the quantized transform coefficients to form a one-dimensional vector, the video encoder 200 may entropy encode the one-dimensional vector, for example, according to context-adaptive binary arithmetic coding (CABAC). The video encoder 200 may also entropy encode values for syntax elements that describe metadata associated with the encoded video data for use by the video decoder 300 when decoding the video data.

[0079] To perform CABAC, the video encoder 200 may assign context within a context model to a symbol to be transmitted. The context may relate to, for example, whether the neighboring values of the symbol are zero values. The probability determination may be based on the context assigned to the symbol.

[0080] The video encoder 200 may further generate, for example, block-based syntax data, picture-based syntax data, and sequence-based syntax data, or other syntax data such as a sequence parameter set (SPS), a picture parameter set (PPS), or a video parameter set (VPS) to the video decoder 300 in a picture header, a block header, or a slice header. The video decoder 300 may also decode such syntax data to determine how to decode the corresponding video data.

[0081] In this way, the video encoder 200 can generate a bitstream that includes the encoded video data, such as syntax elements describing the partitioning of a picture into blocks (e.g., CUs) and prediction and / or residual information for the blocks. Ultimately, the video decoder 300 can receive the bitstream and decode the encoded video data.

[0082] In general, the video decoder 300 performs a process that is inverse to that performed by the video encoder 200 to decode the encoded video data of the bitstream. For example, the video decoder 300 can use CABAC to decode values for syntax elements of the bitstream in a manner that is substantially similar, though inverse, to the CABAC encoding process of the video encoder 200. The syntax elements can define partitioning information for the partitioning of a picture into CTUs, as well as the partitioning of each CTU according to a corresponding partitioning structure, such as a QTBT structure, to define the CUs of the CTU. The syntax elements can further define prediction and residual information for a block (e.g., a CU) of video data.

[0083] The residual information may be represented by, for example, quantized transform coefficients. The video decoder 300 may inverse quantize and inverse transform the quantized transform coefficients of the block to reproduce a residual block for the block. The video decoder 300 uses the signaled prediction mode (intra-frame or inter-frame prediction) and related prediction information (e.g., motion information for inter-frame prediction) to form a prediction block for the block. The video decoder 300 may then combine the prediction block and the residual block (on a sample-by-sample basis) to reproduce the original block. The video decoder 300 may perform additional processing, such as performing a deblocking process to reduce visual artifacts along block boundaries.

[0084] The present disclosure may generally refer to "signaling" certain information, such as syntax elements. The term "signaling" may generally refer to the communication of values for syntax elements and / or other data used to decode encoded video data. That is, the video encoder 200 may signal values for syntax elements in a bitstream. Generally speaking, signaling involves generating values in the bitstream. As described above, the source device 102 may transmit the bitstream to the destination device 116 in substantially real time or in non-real time, such as may occur when storing syntax elements to the storage device 112 for later retrieval by the destination device 116.

[0085] Figure 2A and Figure 2Bis a conceptual diagram illustrating an example quadtree binary tree (QTBT) structure 130 and a corresponding codec tree unit (CTU) 132. Solid lines represent quadtree partitioning, and dashed lines indicate binary tree partitioning. In each partition node (i.e., non-leaf node) of the binary tree, a flag is signaled to indicate which partition type (i.e., horizontal or vertical) is used, where in this example, 0 indicates horizontal partitioning and 1 indicates vertical partitioning. For quadtree partitioning, since the quadtree node divides the block horizontally and vertically into 4 sub-blocks of equal size, there is no need to indicate the partition type. Accordingly, the video encoder 200 can encode syntax elements (such as partition information) for the region tree level (i.e., solid line) of the QTBT structure 130 and syntax elements (such as partition information) for the prediction tree level (i.e., dashed line) of the QTBT structure 130, and the video decoder 300 can decode these syntax elements. The video encoder 200 may encode video data (such as prediction and transform data) for the CU represented by the terminal leaf node of the QTBT structure 130 , and the video decoder 300 may decode the video data.

[0086] Generally speaking, Figure 2B The CTU 132 may be associated with parameters that define the size of blocks corresponding to nodes of the QTBT structure 130 at the first and second levels. These parameters may include a CTU size (indicating the size of the CTU 132 in samples), a minimum quadtree size (MinQTSize, indicating the minimum allowed quadtree leaf node size), a maximum binary tree size (MaxBTSize, indicating the maximum allowed binary tree root node size), a maximum binary tree depth (MaxBTDepth, indicating the maximum allowed binary tree depth), and a minimum binary tree size (MinBTSize, indicating the minimum allowed binary tree leaf node size).

[0087] The root node of the QTBT structure corresponding to the CTU can have four child nodes at the first level of the QTBT structure, each of which can be split according to the quadtree partitioning. That is, the nodes at the first level are either leaf nodes (no child nodes) or have four child nodes. The example of the QTBT structure 130 represents such nodes as including a parent node and child nodes with solid lines for branching. If the nodes at the first level are not larger than the maximum allowed binary tree root node size (MaxBTSize), these nodes can be further split by the corresponding binary tree. The binary tree partitioning of a node can be iterated until the node obtained by the partition reaches the minimum allowed binary tree leaf node size (MinBTSize) or the maximum allowed binary tree depth (MaxBTDepth). The example of the QTBT structure 130 represents such nodes as having dotted lines for branching. The binary tree leaf nodes are called coding units (CUs), which are used for prediction (e.g., intra-picture prediction or inter-picture prediction) and transformation without any further partitioning. As discussed above, CUs can also be referred to as "video blocks" or "blocks."

[0088] In one example of a QTBT partitioning structure, the CTU size is set to 128×128 (a luma sample and two corresponding 64×64 chroma samples), MinQTSize is set to 16×16, MaxBTSize is set to 64×64, MinBTSize (for both width and height) is set to 4, and MaxBTDepth is set to 4. Quadtree partitioning is first applied to the CTU to generate quadtree leaf nodes. Quadtree leaf nodes can have sizes from 16×16 (i.e., MinQTSize) to 128×128 (i.e., CTU size). If a leaf quadtree node is 128×128, then since its size exceeds MaxBTSize (64×64 in this example), the leaf quadtree node will not be further partitioned by the binary tree. Otherwise, the leaf quadtree node will be further partitioned by the binary tree. Therefore, the quadtree leaf node is also the root node of the binary tree, and the binary tree depth is 0. When the binary tree depth reaches MaxBTDepth (4 in this example), no further splitting is allowed. When the width of a binary tree node is equal to MinBTSize (4 in this example), it means that no further horizontal splitting (that is, splitting in width) is allowed for the binary tree node. Similarly, a binary tree node with a height equal to MinBTSize means that no further vertical splitting (that is, splitting in height) is allowed for the binary tree node. As described above, the leaf nodes of the binary tree are called CUs and are further processed according to prediction and transformation without further segmentation.

[0089] As will be described in greater detail below, the video encoder 200 and the video decoder 300 can each be configured to: determine that a block of video data is to be encoded in a geometric partitioning mode; determine an angle for the block of video data in the geometric partitioning mode; determine a dividing line displacement relative to a center of the block in the geometric partitioning mode; partition the block into a first partition and a second partition based on the angle and the dividing line displacement; locate a first prediction sample for the block of video data using a motion vector for the first partition; locate a second prediction sample for the block of video data using a motion vector for the second partition; determine a power of two based on the angle of the block of video data; determine a weight value based on the power of two; perform a blending operation on the first prediction sample and the second prediction sample to determine a prediction block for the block of video data; and output the prediction block. By determining the power of two based on the angle of the block of video data and determining the weight value based on the power of two, the video encoder 200 and the video decoder 300 can advantageously be configured to encode and decode a block of video data in the geometric partitioning mode with reduced computational complexity compared to the prior art. For example, the video encoder 200 and the video decoder 300 can utilize shift operations, rather than sine and cosine operations, when determining a prediction block for encoding or decoding. Compared with sine and cosine operations, the computational complexity of shift operations can be greatly reduced.

[0090] Figure 3 is a block diagram illustrating an example video encoder 200 that may perform the techniques of this disclosure. Figure 3 This is provided for illustrative purposes and should not be considered limiting of the techniques broadly illustrated and described in this disclosure. For illustrative purposes, this disclosure describes the video encoder 200 in the context of video codec standards such as the HEVC video codec standard and the developing H.266 / VVC video codec standard. However, the techniques of this disclosure are not limited to these video codec standards and are generally applicable to video encoding and decoding.

[0091] exist Figure 3In the example of FIG, the video encoder 200 includes a video data memory 230, a mode selection unit 202, a residual generation unit 204, a transform processing unit 206, a quantization unit 208, an inverse quantization unit 210, an inverse transform processing unit 212, a reconstruction unit 214, a filter unit 216, a decoded picture buffer (DPB) 218, and an entropy coding unit 220. Any or all of the video data memory 230, the mode selection unit 202, the residual generation unit 204, the transform processing unit 206, the quantization unit 208, the inverse quantization unit 210, the inverse transform processing unit 212, the reconstruction unit 214, the filter unit 216, the DPB 218, and the entropy coding unit 220 can be implemented in one or more processors or in processing circuits. In addition, the video encoder 200 can include additional or alternative processors or processing circuits to perform these functions and other functions.

[0092] The video data memory 230 may store video data to be encoded by the components of the video encoder 200. The video encoder 200 may receive video data from, for example, the video source 104 ( Figure 1 ) receives video data stored in the video data memory 230. The DPB 218 can act as a reference picture memory that stores reference video data for predicting subsequent video data by the video encoder 200. The video data memory 230 and the DPB 218 can be formed by any of a variety of memory devices, such as dynamic random access memory (DRAM), including synchronous DRAM (SDRAM), magnetoresistive RAM (MRAM), resistive RAM (RRAM), or other types of memory devices. The video data memory 230 and the DPB 218 can be provided by the same memory device or separate memory devices. In various examples, the video data memory 230 can be on-chip with the other components of the video encoder 200 (as shown), or off-chip relative to those components.

[0093] In this disclosure, references to the video data memory 230 should not be construed as limited to memory internal to the video encoder 200, unless specifically described as such, or as limited to memory external to the video encoder 200, unless specifically described as such. Rather, references to the video data memory 230 should be understood as reference memory that stores video data received by the video encoder 200 for encoding (e.g., video data of a current block to be encoded). Figure 1The memory 106 may also provide temporary storage of outputs from the various units of the video encoder 200 .

[0094] Show Figure 3 The various units of the video encoder 200 are described to help understand the operations performed by the video encoder 200. These units can be implemented as fixed-function circuits, programmable circuits, or a combination thereof. Fixed-function circuits refer to circuits that provide specific functionality and are preset with respect to the operations that can be performed. Programmable circuits refer to circuits that can be programmed to perform various tasks and provide flexible functionality in the operations that can be performed. For example, a programmable circuit can execute software or firmware so that the programmable circuit operates in a manner defined by the instructions of the software or firmware. Fixed-function circuits can execute software instructions (e.g., to receive parameters or output parameters), but the type of operation performed by the fixed-function circuit is generally constant. In some examples, one or more units can be different circuit blocks (fixed-function or programmable), and in some examples, one or more units can be integrated circuits.

[0095] The video encoder 200 may include an arithmetic logic unit (ALU), an elementary function unit (EFU), a digital circuit, an analog circuit, and / or a programmable core formed by a programmable circuit. In an example in which the operation of the video encoder 200 is performed using software executed by a programmable circuit, the memory 106 ( Figure 1 ) may store object code for software received and executed by the video encoder 200, or another memory (not shown) within the video encoder 200 may store such instructions.

[0096] The video data memory 230 is configured to store received video data. The video encoder 200 may retrieve a picture of the video data from the video data memory 230 and provide the video data to the residual generation unit 204 and the mode selection unit 202. The video data in the video data memory 230 may be the original video data to be encoded.

[0097] The mode selection unit 202 includes a motion estimation unit 222, a motion compensation unit 224, and an intra prediction unit 226. The mode selection unit 202 may include additional functional units to perform video prediction according to other prediction modes. For example, the mode selection unit 202 may include a palette unit, an intra block copy unit (which may be part of the motion estimation unit 222 and / or the motion compensation unit 224), an affine unit, a linear model (LM) unit, etc.

[0098] The mode selection unit 202 typically coordinates multiple encoding passes to test combinations of encoding parameters and the resulting rate-distortion values for such combinations. The encoding parameters may include the partitioning of a CTU into CUs, the prediction mode used for a CU, the transform type used for the residual data of a CU, the quantization parameter used for the residual data of a CU, etc. The mode selection unit 202 may ultimately select a combination of encoding parameters that has a better rate-distortion value than other tested combinations.

[0099] The video encoder 200 may partition a picture retrieved from the video data memory 230 into a series of CTUs and encapsulate one or more CTUs into a slice. The mode selection unit 210 may partition the CTUs of the picture according to a tree structure, such as the QTBT structure or quadtree structure of HEVC described above. As described above, the video encoder 200 may form one or more CUs by partitioning the CTUs according to the tree structure. Such CUs may also be generally referred to as "video blocks" or "blocks."

[0100] Generally speaking, the mode select unit 202 also controls its components (e.g., the motion estimation unit 222, the motion compensation unit 224, and the intra prediction unit 226) to generate a prediction block for the current block (e.g., the current CU, or, in HEVC, the overlapping portion of the PU and TU). For inter prediction of the current block, the motion estimation unit 222 may perform a motion search to identify one or more closely matching reference blocks in one or more reference pictures (e.g., one or more previously coded pictures stored in the DPB 218). In particular, the motion estimation unit 222 may calculate values representing how similar the potential reference blocks are to the current block, for example, based on the sum of absolute differences (SAD), sum of squared differences (SSD), mean absolute difference (MAD), mean squared difference (MSD), etc. The motion estimation unit 222 may generally perform these calculations using the sample-by-sample differences between the current block and the reference block under consideration. The motion estimation unit 222 may identify the reference block with the lowest value resulting from these calculations, indicating the reference block that most closely matches the current block.

[0101] Motion estimation unit 222 may form one or more motion vectors (MVs) that define the position of a reference block in a reference picture relative to the position of a current block in a current picture. Motion estimation unit 222 may then provide the motion vectors to motion compensation unit 224. For example, for unidirectional inter prediction, motion estimation unit 222 may provide a single motion vector, while for bidirectional inter prediction, motion estimation unit 222 may provide two motion vectors. Motion compensation unit 224 may then use the motion vectors to generate a prediction block. For example, motion compensation unit 224 may use the motion vectors to retrieve data for the reference block. As another example, if the motion vectors have fractional sample precision, motion compensation unit 224 may interpolate values for the prediction block based on one or more interpolation filters. Furthermore, for bidirectional inter prediction, motion compensation unit 224 may retrieve data for the two reference blocks identified by the corresponding motion vectors, for example, by sample-by-sample averaging or weighted averaging, and combine the retrieved data.

[0102] As another example, for intra prediction or intra prediction codecs, the intra prediction unit 226 can generate a prediction block based on samples adjacent to the current block. For example, for directional mode, the intra prediction unit 226 can generally mathematically combine the values of the adjacent samples and pad these calculated values in a defined direction across the current block to produce a prediction block. As another example, for DC mode, the intra prediction unit 226 can calculate the average of the adjacent samples for the current block and generate a prediction block to include the resulting average for each sample of the prediction block.

[0103] Mode selection unit 202 provides the prediction block to residual generation unit 204. Residual generation unit 204 receives the original, unencoded version of the current block from video data memory 230 and the prediction block from mode selection unit 202. Residual generation unit 204 calculates the sample-by-sample difference between the current block and the prediction block. The resulting sample-by-sample difference defines a residual block for the current block. In some examples, residual generation unit 204 may also determine the difference between the sample values in the residual block to generate the residual block using residual differential pulse code modulation (RDPCM). In some examples, residual generation unit 204 may be formed using one or more subtractor circuits that perform binary subtraction.

[0104] In the example where the mode select unit 202 partitions the CU into PUs, each PU may be associated with a luma prediction unit and a corresponding chroma prediction unit. The video encoder 200 and the video decoder 300 may support PUs of various sizes. As indicated above, the size of a CU may refer to the size of the luma codec block of the CU, and the size of a PU may refer to the size of the luma prediction unit of the PU. Assuming that the size of a particular CU is 2Nx2N, the video encoder 200 may support PU sizes of 2Nx2N or NxN for intra prediction, and symmetric PU sizes of 2Nx2N, 2NxN, Nx2N, NxN, or similar for inter prediction. The video encoder 200 and the video decoder 300 may also support asymmetric partitioning of PU sizes of 2NxnU, 2NxnD, nLx2N, and nRx2N for inter prediction.

[0105] In an example where the mode selection unit does not further split the CU into PUs, each CU can be associated with a luma codec block and a corresponding chroma codec block. As described above, the size of a CU can refer to the size of the luma codec block of the CU. The video encoder 200 and the video decoder 300 can support CU sizes of 2Nx2N, 2NxN, or Nx2N.

[0106] For other video codecs, such as intra block copy mode codecs, affine mode codecs, and linear model (LM) mode codecs (to name a few), the mode selection unit 202 generates a prediction block for the current block being encoded via various units associated with the codec. In some examples, such as palette mode codecs, the mode selection unit 202 may not generate a prediction block, but instead generate syntax elements that indicate how to reconstruct the block based on the selected palette. In such a mode, the mode selection unit 202 may provide these syntax elements to the entropy coding unit 220 to be encoded.

[0107] As described above, the residual generation unit 204 receives video data of a current block and a corresponding prediction block. The residual generation unit 204 then generates a residual block for the current block. To generate the residual block, the residual generation unit 204 calculates the sample-by-sample difference between the prediction block and the current block.

[0108] The transform processing unit 206 applies one or more transforms to the residual block to generate a block of transform coefficients (referred to herein as a "transform coefficient block"). The transform processing unit 206 may apply various transforms to the residual block to form the transform coefficient block. For example, the transform processing unit 206 may apply a discrete cosine transform (DCT), a directional transform, a Karhunen-Loeve transform (KLT), or a conceptually similar transform to the residual block. In some examples, the transform processing unit 206 may perform multiple transforms on the residual block, for example, a primary transform and a secondary transform (such as a rotation transform). In some examples, the transform processing unit 206 does not apply a transform to the residual block.

[0109] The quantization unit 208 may quantize the transform coefficients in the transform coefficient block to produce a quantized transform coefficient block. The quantization unit 208 may quantize the transform coefficients of the transform coefficient block according to a quantization parameter (QP) value associated with the current block. The video encoder 200 (e.g., via the mode selection unit 202) may adjust the degree of quantization applied to the coefficient block associated with the current block by adjusting the QP value associated with the CU. Quantization may introduce information loss, and thus, the quantized transform coefficients may have lower precision than the original transform coefficients produced by the transform processing unit 206.

[0110] The inverse quantization unit 210 and the inverse transform processing unit 212 may apply inverse quantization and inverse transform, respectively, to the quantized transform coefficient block to reconstruct a residual block from the transform coefficient block. The reconstruction unit 214 may generate a reconstructed block corresponding to the current block (albeit potentially with some degree of distortion) based on the reconstructed residual block and the prediction block generated by the mode selection unit 202. For example, the reconstruction unit 214 may add samples of the reconstructed residual block to corresponding samples of the prediction block generated by the mode selection unit 202 to generate the reconstructed block.

[0111] Filter unit 216 may perform one or more filtering operations on the reconstructed block. For example, filter unit 216 may perform a deblocking operation to reduce blocking artifacts along the edges of the CU. In some examples, the operations of filter unit 216 may be skipped.

[0112] The video encoder 200 stores the reconstructed block in the DPB 218. For example, in examples where the operation of the filter unit 216 is not required, the reconstruction unit 214 can store the reconstructed block in the DPB 218. In examples where the operation of the filter unit 216 is required, the filter unit 216 can store the filtered reconstructed block in the DPB 218. The motion estimation unit 222 and the motion compensation unit 224 can retrieve a reference picture formed by the reconstructed (and possibly filtered) block from the DPB 218 to perform inter-frame prediction on blocks of subsequently encoded pictures. In addition, the intra-frame prediction unit 226 can use the reconstructed block in the DPB 218 of the current picture to perform intra-frame prediction on other blocks in the current picture.

[0113] In general, the entropy coding unit 220 may entropy encode syntax elements received from other functional components of the video encoder 200. For example, the entropy coding unit 220 may entropy encode quantized transform coefficient blocks from the quantization unit 208. As another example, the entropy coding unit 220 may entropy encode prediction syntax elements (e.g., motion information for inter-prediction or intra-mode information for intra-prediction) from the mode selection unit 202. The entropy coding unit 220 may perform one or more entropy encoding operations on syntax elements, another example of video data, to generate entropy-encoded data. For example, entropy coding unit 220 can perform a context-adaptive variable length coding (CAVLC) operation, a CABAC operation, a variable-to-variable (V2V) length coding operation, a syntax-based context-adaptive binary arithmetic coding (SBAC) operation, a probability interval partitioning entropy (PIPE) coding operation, an exponential-Golomb coding operation, or another entropy coding operation on the data. In some examples, entropy coding unit 220 can operate in a bypass mode in which syntax elements are not entropy encoded.

[0114] The video encoder 200 may output a bitstream including entropy coding syntax elements required to reconstruct a block of a slice or picture. Specifically, the entropy coding unit 220 may output a bitstream.

[0115] The operations described above are described with respect to blocks. Such descriptions should be understood as operations for luma codec blocks and / or chroma codec blocks. As described above, in some examples, the luma codec blocks and chroma codec blocks are the luma and chroma components of a CU. In some examples, the luma codec blocks and chroma codec blocks are the luma and chroma components of a PU.

[0116] In some examples, operations performed with respect to chroma codec blocks do not need to be repeated for luma codec blocks. As an example, operations performed for luma codec blocks to identify motion vectors (MVs) and reference pictures do not need to be repeated for chroma blocks to identify MVs and reference pictures. Instead, the MVs for luma codec blocks can be scaled to determine the MVs for chroma blocks, while the reference pictures can be the same. As another example, the intra prediction process can be the same for luma and chroma codec blocks.

[0117] Video encoder 200 represents an example of a device configured to encode video data, the device comprising: a memory configured to store the video data, and one or more processing units implemented in circuitry according to any one or a combination of the techniques described in this disclosure and configured to encode using a geometric partitioning pattern.

[0118] Figure 4 is a block diagram illustrating an example video decoder 300 that may perform the techniques of this disclosure. Figure 4 This is provided for illustrative purposes and does not limit the techniques broadly illustrated and described in this disclosure. For illustrative purposes, this disclosure describes a video decoder 300 based on techniques from JEM, VVC, and HEVC. However, the techniques of this disclosure can be performed by video codec devices configured for other video codec standards.

[0119] exist Figure 4 In the example of FIG, the video decoder 300 includes a coded picture buffer (CPB) memory 320, an entropy decoding unit 302, a prediction processing unit 304, an inverse quantization unit 306, an inverse transform processing unit 308, a reconstruction unit 310, a filter unit 312, and a decoded picture buffer (DPB) 314. Any one or all of the CPB memory 320, the entropy decoding unit 302, the prediction processing unit 304, the inverse quantization unit 306, the inverse transform processing unit 308, the reconstruction unit 310, the filter unit 312, and the DPB 314 may be implemented in one or more processors or processing circuits. Moreover, the video decoder 300 may include additional or alternative processors or processing circuits to perform these functions or other functions.

[0120] The prediction processing unit 304 includes a motion compensation unit 316 and an intra prediction unit 318. The prediction processing unit 304 may include an addition unit to perform prediction according to other prediction modes. As an example, the prediction processing unit 304 may include a palette unit, an intra block copy unit (which may form part of the motion compensation unit 316), an affine unit, a linear model (LM) unit, etc. In other examples, the video decoder 300 may include more, fewer, or different functional components.

[0121] The CPB memory 320 may store video data, such as an encoded video bitstream, to be decoded by components of the video decoder 300. The video data stored in the CPB memory 320 may be, for example, received from the computer-readable medium 110 ( Figure 1 ). The CPB memory 320 may include a CPB that stores coded video data (e.g., syntax elements) from a coded video bitstream. Furthermore, the CPB memory 320 may store video data other than syntax elements for coded or decoded pictures, such as temporary data representing outputs from various units of the video decoder 300. The DPB 314 typically stores decoded pictures, which the video decoder 300 may output and / or use as reference video data when decoding subsequent data or pictures in the coded video bitstream. The CPB memory 320 and the DPB 314 may be formed from any of a variety of memory devices, such as dynamic random access memory (DRAM), including synchronous DRAM (SDRAM), magnetoresistive RAM (MRAM), resistive RAM (RRAM), or other types of memory devices. The CPB memory 320 and the DPB 314 may be provided by the same memory device or separate memory devices. In various examples, the CPB memory 320 may be located on-chip with the other components of the video decoder 300, or off-chip relative to these components.

[0122] Additionally or alternatively, in some examples, video decoder 300 may retrieve the video from memory 120 ( Figure 1 ) retrieves the encoded and decoded video data. That is, memory 120 may store data along with CPB memory 320 as discussed above. Likewise, when some or all of the functionality of video decoder 300 is implemented in software to be executed by the processing circuitry of video decoder 300, memory 120 may store instructions to be executed by video decoder 300.

[0123] Figure 4 The various units shown are shown to aid in understanding the operations performed by the video decoder 300. These units may be implemented as fixed function circuits, programmable circuits, or a combination thereof. Figure 3 Similarly, fixed-function circuitry refers to circuitry that provides specific functionality and has preset operations that can be performed. Programmable circuitry refers to circuitry that can be programmed to perform various tasks and provides flexible functionality in the operations that can be performed. For example, a programmable circuit can execute software or firmware so that the programmable circuit operates in a manner defined by the instructions of the software or firmware. Fixed-function circuitry can execute software instructions (e.g., to receive parameters or output parameters), but the type of operation performed by the fixed-function circuitry is generally constant. In some examples, one or more units may be different circuit blocks (fixed-function or programmable), while in some examples, one or more units may be integrated circuits.

[0124] The video decoder 300 may include an ALU, an EFU, a digital circuit, an analog circuit, and / or a programmable core formed by a programmable circuit. In an example where the operation of the video decoder 300 is performed by software executed on the programmable circuit, an on-chip or off-chip memory may store instructions (e.g., object code) of the software received and executed by the video decoder 300.

[0125] The entropy decoding unit 302 may receive the encoded video data from the CPB and perform entropy decoding on the video data to reproduce syntax elements. The prediction processing unit 304, the inverse quantization unit 306, the inverse transform processing unit 308, the reconstruction unit 310, and the filter unit 312 may generate decoded video data based on the syntax elements extracted from the bitstream.

[0126] Typically, the video decoder 300 reconstructs a picture on a block-by-block basis. The video decoder 300 may perform a reconstruction operation on each block individually (where the block currently being reconstructed, ie, the block being decoded, may be referred to as a "current block").

[0127] The entropy decoding unit 302 may entropy decode syntax elements defining the quantized transform coefficients of the quantized transform coefficient block, as well as transform information such as a quantization parameter (QP) and / or a transform mode indication. The inverse quantization unit 306 may use the QP associated with the quantized transform coefficient block to determine a degree of quantization and, similarly, to determine a degree of inverse quantization to be applied by the inverse quantization unit 306. The inverse quantization unit 306 may, for example, perform a bitwise left shift operation to inverse quantize the quantized transform coefficients. The inverse quantization unit 306 may thereby form a transform coefficient block comprising the transform coefficients.

[0128] After the inverse quantization unit 306 forms the transform coefficient block, the inverse transform processing unit 308 may apply one or more inverse transforms to the transform coefficient block to generate a residual block associated with the current block. For example, the inverse transform processing unit 308 may apply an inverse DCT transform, an inverse integer transform, an inverse Karhunen-Loeve transform (KLT), an inverse rotation transform, an inverse directional transform, or another inverse transform to the transform coefficient block.

[0129] In addition, prediction processing unit 304 generates a prediction block based on the prediction information syntax element entropy decoded by entropy decoding unit 302. For example, if the prediction information syntax element indicates that the current block is inter-predicted, motion compensation unit 316 may generate a prediction block. In this case, the prediction information syntax element may indicate a reference picture in DPB 314 from which to retrieve the reference block, and a motion vector that identifies the position of the reference block in the reference picture relative to the position of the current block in the current picture. Motion compensation unit 316 may generally generate a prediction block in a manner substantially similar to that described with respect to motion compensation unit 224 ( Figure 3 ) to perform inter-frame prediction processing in the manner described.

[0130] As another example, if the prediction information syntax element indicates that the current block is intra-predicted, the intra-prediction unit 318 may generate a prediction block according to the intra-prediction mode indicated by the prediction information syntax element. Similarly, the intra-prediction unit 318 may generally generate a prediction block in the same manner as the intra-prediction unit 226 ( Figure 3 The intra prediction unit 318 may retrieve data for neighboring samples of the current block from the DPB 314.

[0131] The reconstruction unit 310 may reconstruct the current block using the prediction block and the residual block. For example, the reconstruction unit 310 may add samples of the residual block to corresponding samples of the prediction block to reconstruct the current block.

[0132] The filter unit 312 may perform one or more filtering operations on the reconstructed block. For example, the filter unit 312 may perform a deblocking operation to reduce blocking artifacts along the edges of the reconstructed block. The operations of the filter unit 312 may not necessarily be performed in all examples.

[0133] The video decoder 300 may store the reconstructed block in the DPB 314. For example, in an example where the operation of the filter unit 312 is not performed, the reconstruction unit 310 may store the reconstructed block to the DPB 314. In an example where the operation of the filter unit 312 is performed, the reconstruction unit 310 may store the filtered reconstructed block to the DPB 314. As discussed above, the DPB 314 may provide reference information to the prediction processing unit 304, such as samples of the current picture for intra-frame prediction and samples of previously decoded pictures for subsequent motion compensation. In addition, the video decoder 300 may output a decoded picture (e.g., a decoded video) from the DPB 314 for subsequent use in, for example, Figure 1 The display device 118 is displayed on the display device.

[0134] In this manner, video decoder 300 represents an example of a video decoding device comprising a memory configured to store video data, and one or more processing units implemented in a circuit system according to any one or a combination of the techniques described in this disclosure and configured to decode using a geometric partitioning pattern.

[0135] As mentioned above, video compression technology performs spatial and temporal prediction to reduce or remove the redundancy inherent in the input video signal. In order to reduce temporal redundancy (i.e., the similarity between video signals in adjacent frames), motion estimation is performed to track the motion of video objects. Motion estimation can be performed on blocks of variable size. The object displacement resulting from motion estimation is usually called a motion vector. Motion vectors can have half-pixel, quarter-pixel, 1 / 16 pixel accuracy (or any higher accuracy). This allows the video encoder to track the motion field with higher accuracy than integer pixel positions, thereby obtaining better predicted blocks. When using motion vectors with fractional pixel values, an interpolation operation is performed.

[0136] After motion estimation, a specific rate-distortion model can be used to determine the optimal motion vector. The optimal motion vector is then used to form a predicted video block (i.e., a prediction block) through motion compensation. A residual video block is formed by subtracting the predicted video block from the original video block. A transform is then applied to the residual block. The transform coefficients are then quantized and entropy coded to further reduce the bit rate.

[0137] As mentioned above, Figure 3 is a block diagram of a video encoder 200 that uses block-based motion estimation to reduce temporal redundancy. Some video codecs, such as the H.264 / AVC or HEVC standards, also allow for spatial prediction of intra-frame coded blocks, which is useful in Figure 3 Not depicted.

[0138] When using triangle partitioning mode, the CU is evenly divided into two triangular partitions using diagonal partitioning or anti-diagonal partitioning, such as Figure 5A and Figure 5B For example, Figure 5A and Figure 5B Block 500A and block 500B are shown, respectively. Block 500A is partitioned into a first partition 502A and a second partition 504A, and block 500B is partitioned into a first partition 502B and a second partition 504B.

[0139] Each triangular partition in a CU predicts each other using its own motion. Only unidirectional prediction may be allowed for each partition. That is, each partition (e.g., partition 502A, 504A, 502B, or 504B) has one motion vector and one reference index in the reference picture list. Unidirectional prediction motion constraints are applied to ensure that (similar to traditional bidirectional prediction) only two motion compensated predictions are required for each CU (i.e., only two blocks can be blended together to form a predicted block). For example, partition 502A and partition 504A may each have only one motion vector, which means that block 500A is limited to only two motion vectors.

[0140] The unidirectional prediction motion for each partition (e.g., the first motion vector of the first partition 502A and the second motion vector of the second partition 504A, similarly for partitions 502B and 504B) is derived from a unidirectional prediction candidate list constructed using the process described for unidirectional prediction candidate list construction. If the CU level flag indicates that the current CU is coded using triangle partitioning mode, and if triangle partitioning mode is used, a flag indicating the direction of the triangle partitioning (diagonal or anti-diagonal) and two merge indices (one for each partition) are further signaled. Figure 5A and Figure 5B Examples of diagonal and anti-diagonal segmentation are shown with respective dashed segmentation lines.

[0141] After predicting each triangle partition (e.g., determining a first prediction block for the first partition 502A or 502B and a second prediction block for the second partition 504A or 504B based on the corresponding motion vectors), a blending process with adaptive weights is used to adjust the sample values along the diagonal or anti-diagonal edges (e.g., the partition lines). For example, the video encoder 200 and the video decoder 300 can generate a final prediction block by blending the first partition block and the second partition block using adaptive weights. This is the prediction signal for the entire CU (e.g., the final prediction block), and the transform and quantization process can be applied to the entire CU as in other prediction modes. The motion field of a CU predicted using the triangle partition mode is stored in 4x4 units, as described with respect to blending along the triangle partition edges.

[0142] The following describes the construction of the unidirectional prediction candidate list. The unidirectional prediction candidate list includes five unidirectional prediction motion vector candidates. The motion vector candidates are derived from seven adjacent blocks, which include five spatially adjacent blocks ( Figure 6 601–605 of block 600) and two time-coexisting blocks ( Figure 6 (labeled as 606 and 607 in

[15] ). The motion vectors of the seven neighboring blocks are collected and put into the unidirectional prediction candidate list according to the following order: first, the motion vectors of the unidirectionally predicted neighboring blocks; then, for the bidirectionally predicted neighboring blocks, the L0 (list 0) motion vector (i.e., the L0 motion vector portion of the bidirectionally predicted MV), the L1 (list 1) motion vector (i.e., the L1 motion vector portion of the bidirectionally predicted MV), and the average motion vector of the L0 and L1 motion vectors of the bidirectionally predicted MV. If the number of candidates is less than five, a zero motion vector is added to the end of the list.

[0143] L0 or List 0 and L1 or List 1 refer to reference picture lists. For example, for inter-frame prediction, the video encoder 200 and the video decoder 300 each construct one or two reference picture lists (e.g., List 0 and / or List 1). The (multiple) reference picture lists include multiple reference pictures, and an index into one or more reference picture lists is used to identify the one or more reference pictures used for inter-frame prediction. A List 0 motion vector or a List 1 motion vector refers to a motion vector that points to a reference picture identified in List 0 or List 1, respectively. For example, the video encoder 200 or the video decoder 300 can determine whether a motion vector is from a reference picture list, which may mean that the video encoder 200 and the video decoder 300 determine whether the motion vector points to a reference picture stored in a first reference picture list (e.g., List 0) or a second reference picture list (e.g., List 1).

[0144] The following describes the triangle prediction mode (TPM) motion inference from the merge list. The following describes the TPM candidate list construction. Given a merge candidate index, a unidirectional prediction motion vector is derived from the merge candidate list. For a candidate in the merge list, the LX MV of the candidate (X equals the parity of the merge candidate index) is used as the unidirectional prediction motion vector for the triangle partitioning mode. These motion vectors are in Figure 7In the example above, the L(1-X) motion vector of the same candidate in the extended merge prediction candidate list is used as the unidirectional prediction motion vector for the triangle partitioning mode, in the absence of a corresponding LX motion vector. For example, assuming that the merge list consists of 5 sets of bidirectional prediction motion, the TPM candidate list consists of the L0 / L1 / L0 / L1 / L0 MVs of the 0th / 1st / 2nd / 3rd / 4th merge candidates from the first to the last. The TPM mode then includes signaling two different merge indices, one for each triangle partition, to indicate the use of a candidate in the TPM candidate list.

[0145] The following describes blending along the edges of triangle partitions. After each triangle partition is predicted using its own motion, the two prediction signals are blended to derive samples around the diagonal or anti-diagonal edges. The following weights are used in the blending process: for luma, {7 / 8, 6 / 8, 5 / 8, 4 / 8, 3 / 8, 2 / 8, 1 / 8}, e.g. Figure 8A and for chroma, {6 / 8, 4 / 8, 2 / 8}, as shown in Figure 8B As shown in .

[0146] Stated another way, Figure 8A and Figure 8B The final prediction blocks for luminance and chrominance generated for the current block are shown respectively. The current block is divided by a diagonal line from the upper left corner to the lower right corner to form a first partition and a second partition. The video encoder 200 and the video decoder 300 can determine the first prediction block based on the first motion vector and determine the second prediction block based on the second motion vector. The video encoder 200 and the video decoder 300 can determine the first prediction block based on the first motion vector and determine the second prediction block based on the second motion vector. Figure 8A and Figure 8B The weights shown are used to mix the first prediction block and the second prediction block.

[0147] For example, to generate the top-left prediction sample in the final prediction block, the video encoder 200 and the video decoder 300 may scale the top-left prediction sample in the first prediction block by 4 / 8, scale the top-left prediction sample in the second prediction block by 4 / 8, and add the results (e.g., 4 / 8*P1+4 / 8*P2). To generate the prediction sample to the right of the top-left prediction sample in the final prediction block, the video encoder 200 and the video decoder 300 may scale the prediction sample to the right of the top-left prediction sample in the first prediction block by 5 / 8, scale the prediction sample to the right of the top-left prediction sample in the second prediction block by 3 / 8, and add the results (e.g., 5 / 8*P1+3 / 8*P2). The video encoder 200 and the video decoder 300 may repeat such operations to generate the final prediction block.

[0148] Some samples in the final prediction block may be equal to co-located samples in the first prediction block or the second prediction block. For example, the upper right sample in the final prediction block 800A is equal to the upper right sample in the first prediction block, which is why the upper right sample in the final prediction block 800A is displayed as P1. The lower right sample in the final prediction block 800A is equal to the lower right sample in the second prediction block, which is why the lower right sample in the final prediction block 800A is displayed as P2.

[0149] Accordingly, Figure 8A and Figure 8B It can be considered as showing the weight indicating the amount of scaled samples in the first prediction block and the amount of scaled samples in the second prediction block to generate the final prediction block for the current block. For example, a weight of 4 means that the samples in the first prediction block are scaled by 4 / 8, and the samples in the second prediction block are scaled by 4 / 8. A weight of 2 means that the samples in the first prediction block are scaled by 2 / 8, and the samples in the second prediction block are scaled by 6 / 8.

[0150] Figure 8A and Figure 8B The weights shown are an example. For example, the weights may be different for blocks of different sizes. In addition, the dividing line may not be from one corner of the block to another corner of the block. For example, in GEO mode, the dividing line may be at different angles. That is, the TPM mode can be considered an example of GEO mode, where the dividing line is a diagonal or anti-diagonal line of the block. However, in GEO mode, the dividing line can have other angles, as illustrated and described in more detail below. In one or more examples, there may be different weights for different dividing angles. The video encoder 200 and the video decoder 300 may store weights for different dividing angles and use the stored weights to determine the amount of scaling samples in the first prediction block and the second prediction block.

[0151] Motion field storage is described below. The motion vectors of a CU encoded in triangular partitioning mode (TPM) or GEO mode are stored in 4x4 units. That is, the video encoder 200 and the video decoder 300 may divide the current block into sub-blocks (e.g., 4x4 in size) and store motion vector information for each sub-block. In some techniques, depending on the position of each 4x4 sub-block, the video encoder 200 and the video decoder 300 may store unidirectional prediction or bidirectional prediction motion vectors, denoted as Mv1 and Mv2, respectively, as unidirectional prediction motion vectors for partition 1 and partition 2. As described, the position of each 4x4 sub-block may determine whether a unidirectional prediction or bidirectional prediction motion vector is stored. In some examples, the position of each 4x4 sub-block may also indicate whether the majority of the 4x4 sub-blocks are in the first partition or in the second partition (e.g., whether the majority of the samples in the 4x4 sub-blocks are in the first partition or in the second partition).

[0152] Partition 1 and partition 2 are triangular blocks located at the upper right corner and lower left corner respectively when the CU is split from the upper left to the lower right (i.e., 45° split), and are triangular blocks located at the upper right corner and lower left corner respectively when the CU is split from the upper right to the lower left (i.e., 135° split). That is, when the split line is 45°, partition 502A is partition 1, and partition 504A is partition 2, as shown in FIG. Figure 5A As shown in , when the dividing line is 135°, partition 502B is partition 1, and partition 504B is partition 2, as shown in Figure 5B . Although this example is described with respect to triangular partitions with 45° or 135° dividing lines, these techniques are not limited thereto. The example techniques can be applied to examples where triangular partitions do not exist, such as in various examples of GEO mode. Even in such examples of GEO mode, there can be a first partition (e.g., partition 1) and a second partition (e.g., partition 2).

[0153] If a 4x4 unit (e.g., a sub-block) is located Figure 8A and Figure 8B For the non-weighted region shown in the example of , Mv1 or Mv2 is stored for the 4x4 cell. Figure 8A and Figure 8B In the case where the non-weighted samples from the first prediction block or the second prediction block are samples in the final prediction block, the video encoder 200 and the video decoder 300 may select Mv1 (e.g., the first motion vector) or Mv2 (e.g., the second motion vector). Otherwise, if the 4x4 unit is located in the weighted region, the bidirectional prediction motion vector is stored. The bidirectional prediction motion vector is derived from Mv1 and Mv2 according to the following process:

[0154] a. If Mv1 and Mv2 come from different reference picture lists (one from L0 and the other from L1), Mv1 and Mv2 are simply combined to form a bidirectional prediction motion vector. That is, the motion vector information for the subblock includes Mv1 and Mv2 (i.e., both the first motion vector and the second motion vector).

[0155] b. Otherwise, if Mv1 and Mv2 are from the same list, only Mv2 is stored (ie, only the second motion vector is stored).

[0156] Geometric partitioning is described below. Geometric partitioning was introduced in JVET-O0489 (Esenlik et al., "Non-CE4: Geometrical partitioning for inter blocks", ITU-T SG16WP 3 and ISO / IEC JTC 1 / SC 29 / WG 11 Joint Video Experts Group (JVET), 15th Meeting: 3-12 July 2019, Gothenburg, Sweden) as a proposed extension to the non-rectangular partitioning introduced by TPM. As introduced in JVET-O0489, geometric partitioning mode (GEO) applies only to CUs encoded or decoded in skip or merge mode, not in MMVD or CIIP mode. For CUs that meet these conditions, a flag is signaled to indicate whether GEO is applied. Figure 9 The TPM in VVC-6 (VVC draft 6) is shown, along with additional shapes proposed for non-rectangular inter-blocks.

[0157] For example, Figure 9 Blocks 900A and 900B are shown partitioned in TPM mode. TPM mode can be considered a subset of GEO mode. In TPM, the partition line extends from one corner to the opposite corner of the block, as shown in blocks 900A and 900B. However, in GEO mode, the partition line is typically diagonal and does not necessarily start or end at the corner of the block. Figure 9 Blocks 900C-900I in FIG. 1 show different examples of dividing lines that do not necessarily start or end at a corner of blocks 900C-900I.

[0158] The total number of GEO segments can be 140. For example, Figure 9 Blocks 900A-900I are shown, but there may be 140 such possible ways to partition a block, which may be desirable for flexibility in determining how to partition, but may increase signaling. For GEO, there may be additional signaling (e.g., Figure 10 ), such as the angle α and the displacement ρ of the dividing line relative to the center of the block. In this example, α and ρ together define Figure 10The position and slope of the dividing line of block 1000. In some examples, α represents a quantized angle between 0 and 360 degrees, separated by 11.25 degrees, and ρ represents a distance with 5 different values (e.g., 5 displacements). The value pairs of α and ρ are stored in a table of size 140x(3+5) / 8=140 bytes. For example, when the separation is 11.25 degrees, there can be 32 angles (e.g., 11.25*32=360). For 5 displacement values, there can be 160 modes, where one mode is a combination of an angle and a displacement (e.g., 32*5=160). Certain redundant modes can be removed, such as a displacement of 0 and an angle of 0, and a displacement of 0 and an angle of 180, which give the same result. By removing redundant modes, the number of modes is 140. If 3 bits are used to store the 5 displacement values, and 5 bits are used to store the 32 angle values, there are a total of 140*(3+5) bits, which when divided by 8 bits per byte, results in 140 bytes.

[0159] In some examples, the video encoder 200 may signal an index into the table and the video decoder 300 may determine the α and ρ values. Based on the α and ρ values, the video decoder 300 may determine the number of cells to be indexed by a block such as Figure 10 The dividing line of block 1000).

[0160] Similar to TPM, GEO partitioning for inter-frame prediction is allowed for unidirectional prediction blocks of not less than 8×8 so as to have the same memory bandwidth as bidirectional prediction blocks on the decoder side (e.g., video decoder 300). Motion vector prediction for GEO partitioning can be consistent with TPM. In the embodiment of JVET-P0068, GEO supports 140 different partitioning methods, which, in addition to TPM dividing the CU into two parts, are distinguished by 32 angles (quantized between 0 and 360°, with equal intervals of 11.25°) and 5 edges relative to the center of the CU. Figure 19A It shows that, starting from Edge0 passing through the center of the CU, 5 edges are evenly distributed along the direction of the normal vector within the CU. Each partition mode in GEO (i.e., a pair of angle index and edge index) is assigned a pixel adaptive weight table to mix the samples on the two partition parts, where the weight value of the sample ranges from 0 to 8 and is determined by the L2 distance from the pixel center position to the edge. Basically, the unit gain constraint is followed when assigning weight values, that is, when a smaller weight value is assigned to the GEO partition, a larger complementary value is assigned to the other partition, totaling 8.

[0161] The calculation of the weight value of each pixel has two aspects: (a) calculating the displacement from the pixel position to the given edge; and (b) mapping the calculated displacement to the weight value through a predefined lookup table.i The method of calculating the displacement from (x, y) to Edge0 is actually the same as the method of calculating the displacement from (x, y) to Edge0, and using Edge0 and Edge i The distance ρ between them is subtracted from the displacement. Figure 19B The geometric relationship between (x, y) and the edge is shown. Specifically, from (x, y) to Edge i The displacement can be formulated as follows:

[0162]

[0163] The value of ρ is the maximum length of the normal vector (in ρ max represents) and the function of edge index i, that is:

[0164]

[0165] Where N is the number of edges supported by GEO, and "1" is to prevent the last edge Edge N-1 Too close to the corner of the CU for some angle indices.

[0166] Replacing (6) with formula (8) enables us to calculate the distance from each pixel (x, y) to a given Edge i In short, It can be expressed as wIdx(x, y). ρ needs to be calculated once for each CU, and wIdx(x, y) needs to be calculated once for each sample point, where multiplication is performed.

[0167] Table 1 below describes the mode signaling. According to the technique described in JVET-00489, GEO mode is signaled as an additional merge mode.

[0168]

[0169]

[0170] Table 1 Syntactic elements introduced by the proposal

[0171] geo_merge_idx0 and geo_merge_idx1 are encoded and decoded using the same CABAC context and binarization as the TPM merge index. geo_partition_idx indicates the partition mode (one of 140 possibilities) and is encoded and decoded using truncated binary binarization and bypass encoding. For example, geo_partition_idx is the index described above for determining the α and ρ values used to determine the partition line, such as Figure 10 As shown in .

[0172] When GEO mode is not selected, TPM can be selected. GEO mode partitions do not include partitions that can be obtained through binary partitioning of TPM. To some extent, the signaling proposed in the JVET-O049 proposal is similar to intra-frame mode signaling, where the TPM partition corresponds to the most likely partition and the GEO mode corresponds to the remaining partition. geo_partition_idx is used as an index into a lookup table that stores α and ρ pairs. As mentioned above, 140 bytes are used to store this table.

[0173] The following describes the blending operation for the luma block. As in the case of TPM, the final prediction of the codec block is obtained by weighted averaging the first unidirectional prediction and the second unidirectional prediction according to the sample weights.

[0174] If distFromLine<=0, then sampleWeight L [x][y]=GeoFilter[distScaled]

[0175] If distFromLine>0, then sampleWeight L [x][y]=8-GeoFilter[distScaled]

[0176] The sample weights are implemented as a lookup table, as shown in Table 2 below:

[0177]

[0178] Table 2 Hybrid filter weights

[0179] distScaled is a quantized measure of the L2 distance (or displacement) from a pixel position within the block to the edge of the geometric partition. The process of calculating this quantization level has two aspects: (a) calculating the maximum displacement and (b) Quantized into several levels. Figure 11A As depicted in , given a WxH CU and an angle α, It can be calculated as follows:

[0180]

[0181] Then, in Before being quantized into levels, it is adjusted with an adjustment offset o (e.g., 0 or 1) to prevent extremely small geometric partitions from being generated for specific angles and CUs, so the quantization step size can be calculated as follows:

[0182]

[0183] Where N (e.g., 5 or 4) is the number of quantization levels. Figure 11B As shown in , given a quantization level and an angle α, the position of each edge (ie, E0, E1, E2, ... with quantization levels 0, 1, 2, ... respectively) can be defined.

[0184] Then, when an edge is given, the projection distance from a random pixel within the CU can be defined. For example, in Figure 12 In , pixel H is located at (x, y) and the given edge is En, where En is the displacement of n*steps from E0 (i.e., or ρ for short). The distance from H to En (i.e., ) can be calculated as follows:

[0185]

[0186] To improve floating point precision, the maximum distance between a pixel and an edge within a CU is quantized (with a predefined step size of 5 / 36) to an interval with an assigned index. The absolute value of the assigned index may be distScaled.

[0187] The above process can be implemented in a table loop. The number of operations required to calculate the sample weights is the order of one addition operation per sample, which has a computational complexity similar to TPM. In more detail, for each sample, distScaled is calculated according to the following two equations:

[0188] distFromLine=((x<<1)+1)*Dis[displacementX]+((y<<1)+1))*Dis[displacementY]–rho

[0189] distScaled=min((abs(distFromLine)+8)>>4,14)

[0190] where the variables rho, displacementX, and displacementY are calculated once per codec block, and Dis[] is a lookup table with 32 entries (8-bit resolution) that stores the cosine values. For each sample, distFromLine can be calculated by incrementing the value by 2*Dis[displacementX] within a sample row, and by 2*Dis[displacementX] from one sample row to the next. A slightly greater addition per sample can be used to obtain the distFromLine value. Additionally, minimum, absolute value, and downshift operations can be utilized without introducing any significant complexity.

[0191] All GEO operations can be implemented using integer arithmetic. The computational complexity of GEO is likely very similar to that of TPM. Additional details on blending operations exist in draft specification revisions, for example, in JVET-O0489, section "8.5.7.5 Sample Weight Derivation for Geometric Partition Merging Mode."

[0192] The following describes the blending operation for chroma blocks. The sample weights calculated for the luma samples are subsampled and used for chroma blending without any calculations. The weight of the chroma sample at coordinate (x, y) is set equal to the weight of the luma sample at coordinate (2x, 2y), relative to the top-left sample of the luma block.

[0193] The derivation of motion vectors is described below. The same merge list derivation process used for TPM is used to derive the motion vectors for each partition of the GEO block. Each partition can only be predicted by a single prediction.

[0194] An example technique for motion vector storage is described below. The luminance sample weights at the four corners of a 4x4 motion storage unit (which are based on Figure 8A and 8B The sum is compared with two thresholds to determine whether to store one of the two unidirectional prediction motion information or the bidirectional prediction motion information. The bidirectional prediction motion information is derived using the same process as TPM.

[0195] Stated another way, in some techniques, the video encoder 200 and the video decoder 300 may divide the current block into sub-blocks (e.g., 4x4 sub-blocks). For each sub-block, the video encoder 200 and the video decoder 300 may determine a sample weight for scaling the samples in the first prediction block and the second prediction block. For example, referring back to Figure 8A , there may be a 4x4 sub-block at the upper left corner of block 800A. The 4x4 sub-block includes a sample at the upper left corner, and its sample weight is 4, indicating that the samples in the first prediction block collocated with the position of the upper left sample in block 800A and the samples in the second prediction block collocated similarly are scaled the same (e.g., 4 / 8*P1+4 / 8*P2, as shown in FIG. Figure 8A ). The 4x4 sub-block includes a sample at the bottom left corner, whose sample weight is 1, indicating that the samples in the first prediction block collocated with the sample at the bottom left corner of the 4x4 sub-block are scaled by 1 / 8, and the samples in the second prediction block collocated similarly are scaled by 7 / 8. The 4x4 sub-block includes a sample at the top right corner, whose sample weight is 7, indicating that the samples in the first prediction block collocated with the sample at the top right corner of the 4x4 sub-block are scaled by 7 / 8, and the samples in the second prediction block collocated similarly are scaled by 1 / 8, as shown in FIG. Figure 8AThe 4x4 sub-block includes a sample at the bottom right corner, and the sample weight is 4, indicating that the samples in the first prediction block collocated with the sample at the bottom right corner of the 4x4 sub-block are scaled by 4 / 8, and similarly, the samples in the second prediction block collocated with the sample are scaled by 4 / 8, which means that the samples in the first prediction block and the second prediction block are scaled by the same amount.

[0196] In this example, the video encoder 200 and the video decoder 300 may add the weights of the four corners of the 4x4 sub-block, i.e., 4+7+1+4=16. The video encoder 200 and the video decoder 300 may compare the resulting value (e.g., 16) with two thresholds to determine whether the video encoder 200 and the video decoder 300 are to store the first motion vector identifying the first prediction block, the second motion vector identifying the second prediction block, or both the first motion vector and the second motion vector as motion vector information for the 4x4 sub-block.

[0197] According to the present technology, instead of or in addition to summing the luma sample weights as described above, the video encoder 200 and the video decoder 300 may determine a set of subblocks, each subblock including at least one sample corresponding to a predicted sample in a final prediction block generated based on equal weights of samples in a first prediction block and samples in a second prediction block. As an example, the video encoder 200 and the video decoder 300 may determine a set of subblocks (e.g., 4x4 subblocks), each subblock including at least one sample with a weight of 4. As described above, if the sample weight is 4, the video encoder 200 may scale the collocated samples in the first prediction block by 4 / 8 (1 / 2) and scale the collocated samples in the second prediction block by 4 / 8 (1 / 2) to generate the predicted samples in the final prediction block.

[0198] In this manner, there is no need to sum the weights at the corners of the sub-block and compare them to a threshold, as is done in some other techniques described above. Instead, the video encoder 200 and the video decoder 300 determine whether the sub-block includes samples for which prediction samples in the final prediction block are generated based on the equal weights of the samples in the first prediction block and the samples in the second prediction block. If the sub-block includes such samples, the video encoder 200 and the video decoder 300 can store a bidirectionally predicted motion vector, and if the sub-block does not include such samples, the video encoder 200 and the video decoder 300 can store a unidirectionally predicted motion vector.

[0199] As described above, a bidirectionally predicted motion vector is not necessarily two motion vectors. Instead, the video encoder 200 and the video decoder 300 may perform certain operations to determine the bidirectionally predicted motion vector. As an example, the video encoder 200 and the video decoder 300 may determine whether a first motion vector identifying a first prediction block and a second motion vector identifying a second prediction block are from different reference picture lists, and one of the following: based on the first motion vector and the second motion vector being from different reference picture lists, store both the first motion vector and the second motion vector for the sub-block, or based on the first motion vector and the second motion vector being from the same reference picture list, select one of the first motion vector or the second motion vector and store the selected one of the first motion vector or the second motion vector for the sub-block.

[0200] The unidirectional prediction motion vector may be one of the first motion vector and the second motion vector. For example, the video encoder 200 and the video decoder 300 may determine a subblock that does not include any samples corresponding to prediction samples in a final prediction block generated based on equal weights of samples in the first prediction block and samples in the second prediction block (e.g., no samples in the subblock have a weight of 4). In this example, the video encoder 200 and the video decoder 300 may determine, for the subblock, whether a majority of the subblock is within the first partition or within the second partition, and, for the subblock, store a first motion vector based on the majority of the subblock being within the first partition, or store a second motion vector based on the majority of the subblock being within the second partition.

[0201] By storing motion vector information using the example techniques described in this disclosure, the video encoder 200 and the video decoder 300 can store motion vector information that provides overall encoding and decoding and visual benefits. For example, the motion vector information stored for each sub-block may affect the strength of the deblocking filter. Using the example techniques described in this disclosure, the motion vector information of the sub-block can determine the strength of the deblocking filter to remove artifacts. In addition, the motion vector information stored for each sub-block may affect the candidate list generated for the merge mode or AMVP mode used to encode and decode subsequent blocks. Using the example techniques described in this disclosure, the motion vector information of the sub-block can be a better candidate for the candidate list than other techniques for generating candidates for the candidate list.

[0202] Part of the transformation of GEO is described below. Since GEO segmentation provides flexibility for inter prediction, even objects with complex shapes can be predicted well; therefore, the residuals are smaller compared to rectangular blocks or only triangular blocks. In some cases, non-zero residuals of GEO blocks are only observed around the inner boundaries, such as Figure 13Some techniques to reduce the residual include setting the size or W×H block to W×(H / n) or (W / n)×H, keeping non-zero residual only around the inner boundaries, as Figure 13 For example, the area captured by reference numeral 1100A can be reoriented to form a rectangular block 1100B, as shown in FIG. Figure 13 With this change, the size of the residual to be processed and the number of coefficients to be signaled can be made smaller by a factor of n. The value of n is signaled in the bitstream and can be equal to 1 (when no partial transform is applied), 2, or 4. In some examples, the partial transform (an example of which is shown in Figure 13 ) can only be applied to GEO and TPM blocks.

[0203] The residual propagation of partial transformation is described below. On the basis of partial transformation, a process similar to deblocking is applied.

[0204] The deblocking operation can be described as follows:

[0205] - Get sample point p on the block boundary marked by the black circle

[0206] - If k <= 3, assign the value of (p>>k) to the sample at position (x, yk)

[0207] - Get sample point p on the block boundary marked by the white circle

[0208] - If k <= 3, assign the value of (p>>k) to the sample at position (x, y+k)

[0209] Figure 14 An example of a k value is provided. The k value is the number of samples between the boundary samples in block 1200 (represented by circles) and the fill samples in block 1200 (below the corresponding arrows). The black and white arrows show the deblocking direction of the upper and lower boundaries.

[0210] The current GEO design can be considered an extension of the TPM. However, there are some design differences that simplify the hardware implementation.

[0211] For example, to simplify the GEO distance calculation, as described above for the blending operation of luma blocks, GEO performs a distance calculation to select the weight to use for each pixel. This equation is of the form:

[0212] dist=x×cos(α)-y×sin(α)-ρ

[0213] =cos(α)×(xy×tan(α))-ρ

[0214] And, ρ as ρ maxThe score is calculated, and:

[0215]

[0216] Where W and H are the width and height of the block, respectively. In the above description, x and y represent the coordinates of a sample point in the block, and (x, y) = (0, 0) is the sample point at the upper left corner.

[0217] This disclosure describes example techniques for varying the angles used in GEO and exploiting their properties to reduce the number of operations. For example, when using angles with tangents that are powers of two (such as angles with aspect ratios of 1:0, 1:1, 1:2, 1:4, 1:8, 1:16, 16:1, 8:1, 4:1, 2:1, 0:1), all tangent multiplications can be replaced with shifts, which is preferred in hardware implementations.

[0218] The following describes a simplification of GEO motion compensation. Currently, GEO requires either generating weights for motion compensation "on the fly" or storing 140 masks for each block size. This process can be expensive to perform on the fly, or the memory cost can be high if all masks are stored. This disclosure describes example techniques for varying the weights used to reduce memory requirements.

[0219] This disclosure describes example techniques that can simplify motion field storage and motion weight derivation for TPMs and GEOs.

[0220] For example, the following describes simplifications of GEO distance calculations. In some examples, all GEO angles are replaced by angles whose tangent is equal to N or 1 / N, where N is an integer. The operation a*cos(α)+b*sin(α) can be replaced by cos(α)*(a+b*tan(α))=cos(α)*(a+b*N) or

[0221] In actual implementations, the video encoder 200 and the video decoder 300 may operate more efficiently (e.g., with fewer computations) using integer arithmetic; however, both cos(α) and sin(α) are floating-point numbers and are less than or equal to 1. Therefore, both multiplications in a*cos(α)+b*sin(α) need to be approximated by integer arithmetic using a lookup table and scaling.

[0222] One possible benefit of the proposed modification is that only the multiplication with cos() needs to be approximated using a lookup table and scaling; the other multiplication is already integer (i.e., using integer operations of tangent and cotangent, as described below). In the case where M is a power of 2 (which is typical for block sizes in video codecs), the multiplication by N can be done by simply shifting left by log2(N). The operation a*cos(α)+b*sin(α) is present in the calculation of rho(ρ), as well as the distance calculation of the MC for each pixel and the distance calculation for the motion memory.

[0223] The following describes integer operations on tangent and cotangent. n , and n is an integer), the multiplication of a number by the tangent value (or cotangent value) can be achieved by using a shift operation alone. As a non-limiting example, without loss of generality, this disclosure uses tangent as an example. When the ratio of CU width to CU height is a power of 2, the tangent value of the angle within a triangle with the same CU width and CU height is also a power of 2. Therefore, the multiplication of this tangent value by a random integer can be reinterpreted by using the following shift operation:

[0224] b*tan(α)=b*2 n =b<<n.

[0225] In some cases, when α is lower than π / 2, the value of n becomes negative and a right shift is performed, resulting in a loss of precision in b*tan(α). To prevent this, the video encoder 200 or the video decoder 300 may add m left shift bits before performing b×tan(α). The value of m is predefined based on the minimum value of the CU width to CU height ratio. For example, the minimum CU aspect ratio in the GEO proposal of JVET-P0068 (Gao et al., “CE4: CE4-1.1, CE4-1.2 and CE4-1.14: Geometric Merge Mode (GEO)”, ITU-T SG 16WP 3 and ISO / IEC JTC 1 / SC 29 / WG 11 Joint Video Experts Group (JVET), 16th Meeting: October 1-11, 2019, Geneva, Switzerland) is 8:64 (compared to 1 / 16 or 2 -4 Same), so we can use 4 to predefine m. Therefore, the above equation becomes:

[0226] b*tan(α)*2 m =b*2 n+m =b<<(n+m).

[0227] In some examples, 2 m This should also apply to all other terms in each equation involving tangent or cotangent multiplications (e.g., to simplify GEO distance compensation or blending operations for luma blocks as described above). For example, cos(α)*(a+b*tan(α)) becomes (cos(α)*((a<<m)+(b<<(n+m)))+off)>>m, where off is a predefined rounding offset, which can be any integer value (e.g., 2 m-1 ).

[0228] In another example, to ensure the accuracy of b*tan(α), the video encoder 200 and the video decoder 300 do not need to increase its accuracy by multiplying itself by a power of 2. The equation b*tan(α) can be expressed in general form as b*tan(α)*M, where M is a positive integer. Therefore, for equations with b*tan(α), integer multiplication and division can be used to reinterpret. For example, cos(α)*(a+b*tan(α)) becomes (cos(α)*(a*M+((b*M)<<n))+off) / M. This division can be approximated by multiplication and right shift. For example, when M=10, X / M can be approximated by using (X*205)>>11, where X is an integer.

[0229] The following describes a simplification of GEO motion compensation. Using this property:

[0230]

[0231] It can be seen that row y+1 will have the same weight as row y, but offset by tan(α).

[0232] When tan(α)=N, the weight value of MC on row y+1 can be the same as that on row y, but shifted by N samples and using 8 and 0 as the starting and ending values. For example, Figure 15 An example of GEO weights using an angle ratio of 2:1 is shown. The bold, italicized portion shows a pattern with a row shift of tan(α) = 2 pixels. When tan(α) = 1 / N, the MC weight values in column x+1 can be the same as those in column x, but shifted by N samples.

[0233] In some examples, this property is used by storing weights for each block size and one row (corresponding column) for each partition (e.g., when tan(α) = 1 / N, the weight value of the MC on column x+1 can be the same as the value on column x, but shifted by N samples). In some examples, instead of storing weights for each possible GEO partition and weight, only weights from one row (or column) are stored (including at least one starting value of "8" and at least one trailing value of "0" for each angle), and this weight is used for each block size and displacement index. Using the starting point of the partition line, the weight can then be applied to the first row (corresponding column) and shifted on each subsequent row (corresponding column).

[0234] In some examples, the offset between rows is determined based on tan(α). When the absolute value (e.g., absolute value) of tan(α) is at least 1, the weights between two adjacent rows are exactly the same, except that the weights in the second row are shifted by n pixels, where n is equal to tan(α). When the absolute value of tan(α) is less than 1, the weights of each |1 / tan(α)| row are exactly the same, except that the weights of each |1 / tan(α)| row are shifted by 1 pixel when tan(α) ≥ 1, or by -1 pixel when tan(α) < 1.

[0235] In some examples, the offset between columns is determined based on cot(α). When the absolute value (e.g., absolute value) of cot(α) is at least 1, the weights between two adjacent columns are exactly the same, except that the weights in the second column are shifted by n pixels, where n is equal to cot(α). When the absolute value of cot(α) is less than 1, the weights of each |1 / cot(α)| column are exactly the same, except that the weights of each |1 / cot(α)| column are shifted by 1 pixel when cot(α) ≥ 1, or by -1 pixel when cot(α) < 1.

[0236] The following describes a simplification of displacement. The displacement definition can be changed as follows: if the tangent of the angle r is greater than or equal to 1, then the weight of the partition with angle r and displacement d at position (x, y) is equal to the weight at position (x+d, y), otherwise if the tangent of the angle r is less than 1, then the weight of the partition with angle r and displacement d at position (x, y) is equal to the weight at position (x, y+d). With this displacement definition, different partitions with the same angle can share the same weight mask, but with an offset of d in the x-coordinate or y-coordinate. Therefore, the storage of the weight mask can be reduced.

[0237] In one example, the step size of d is fixed to a predefined value, which may depend on the selected angle. In one example, the step size of d is determined by ρ / cos(α) and rounded to an integer. Scaling may be performed before rounding. The displacements may be pre-calculated and stored in a 2D lookup table. In some cases, a displacement value is defined for each angle and each displacement index.

[0238] The following describes a simplification of the number of partitions. In some examples, the number of partitions available for GEO can be changed, as 140 different partitions may be too many and affect computational efficiency. In some examples, the angles removed can be as follows: Figure 16 As shown in . Figure 16 is a table showing example angles that are removed to reduce the number of partitions, with the removed angles shown with strikethrough.

[0239] In some examples, to further reduce the number of partitions, not all displacements are available. For all angles, only four distances are kept, instead of the five in the original GEO design. For angles of 0° and 90°, only displacements with indices 1 and 2 are kept.

[0240] Figure 17 is a flowchart illustrating an example method for encoding a current block. The current block may include a current CU. Although with respect to the video encoder 200 ( Figure 1 and Figure 3 ) is described, but it should be understood that other devices may be configured to perform similar Figure 17 method.

[0241] In this example, the video encoder 200 initially predicts a current block (350). For example, the video encoder 200 may form a prediction block for the current block. The video encoder 200 may then calculate a residual block for the current block (352). To calculate the residual block, the video encoder 200 may calculate the difference between the original, unencoded block and the prediction block for the current block. The video encoder 200 may then transform and quantize the coefficients of the residual block (354). Next, the video encoder 200 may scan the quantized transform coefficients of the residual block (356). During or after the scan, the video encoder 200 may entropy encode the transform coefficients (358). For example, the video encoder 200 may encode the transform coefficients using CAVLC or CABAC. The video encoder 200 may then output the entropy encoded data for the block (360).

[0242] Figure 18 is a flowchart illustrating an example method for decoding a current block of video data. The current block may include a current CU. Although with respect to the video decoder 300 ( Figure 1 and Figure 4) is described, but it should be understood that other devices may be configured to perform similar Figure 18 method.

[0243] The video decoder 300 may receive entropy coded data for a current block, such as entropy coded prediction information and entropy coded data of coefficients of a residual block corresponding to the current block (370). The video decoder 300 may entropy decode the entropy coded data to determine the prediction information for the current block and reproduce the coefficients of the residual block (372). The video decoder 300 may predict the current block (374), for example, using an intra-frame or inter-frame prediction mode indicated by the prediction information for the current block to calculate a prediction block for the current block. The video decoder 300 may then inverse scan the reproduced coefficients (376) to create a block of quantized transform coefficients. The video decoder 300 may then inverse quantize and inverse transform the transform coefficients to produce a residual block (378). The video decoder 300 may ultimately decode the current block (380) by combining the prediction block and the residual block.

[0244] Some embodiments are directed to applying GEO using angles whose tangent is a power of 2. In some such embodiments, the angles used by GEO in JVET-P0068 are replaced with angles whose tangent is a power of 2.

[0245] Figure 20 is a conceptual diagram showing examples of angles used for GEO and the corresponding aspect ratios. In this specific example, there are 16 different angles, multiplied by 2 because each angle can be used for +180°, which means that the number of allowed GEO partitions remains 140 and the signaling of GEO does not change. Because the tangent of the example angle is a power of 2, most of the multiplications required for wIdx(x, y) in equation (6) can be replaced by using bit shifts:

[0246]

[0247] In implementations that calculate GEO weights "on the fly," using angles whose tangents are powers of 2, one multiplication per sample can be replaced with a bit shift operation. Since trigonometric functions can be implemented as integer precision operations, eliminating one multiplication helps reduce roundoff errors.

[0248] In some implementations, the codec device (encoder and / or decoder) can store a mask with weights for each CU size and each partition to reduce the number of operations required for GEO, because the weight values are repeated row by row in a phase-shifted manner. This behavior can be expressed in equation (12) as follows:

[0249]

[0250] It can be seen that wIdx(x, y) can be interpreted as inferring a weight value assigned to the immediately previous row, so a row of weight values is the only item required for mask storage.

[0251] In some cases, the value of tan(α) may not be an integer, and cot(α) is used as a replacement, so that the weight values are repeated column by column in a phase-shifted manner, as shown in Equation (18). It can be seen that wIdx(x, y) can be interpreted as inferring a weight value assigned to the row immediately to the left, so a column of weight values is the only item required for mask storage.

[0252]

[0253] In the range 0 to π / 2, there are 4 angles that will produce powers of 2 for cot(α), so equations (15) and (18) can be reconciled by using a 4-bit shift as follows:

[0254]

[0255] In contrast, in JVET-P0068, most angles have non-integer values of tan(α), which means that (x-tan(α), y-1) and (x-1, y-cot(α)) do not fall at the center of the pixel, so this property cannot be used.

[0256] Some examples may include modifications to ρ. To ensure that the weight values remain constant for edge indices, the horizontal or vertical distance between two edges must be exactly an integer number of samples (i.e., 1, 2, 3, etc.). To achieve this, the definition of the step size as specified above can be changed (i.e., ). Instead of directly To quantify, this embodiment includes Quantization is performed and the step size of the calculation is changed from Projection to Specifically, the process can be expressed as:

[0257]

[0258] Where ε is an adjustment offset used to prevent extremely small geometry partitions for certain angles and to avoid zero steps, and o is a rounding offset. The value of ρ can then be calculated as i*step, where i is the edge index.

[0259] Some further examples include applying GEO weight calculations to TPM. For example, TPM weight values can be calculated in the same way as GEO. GEO and TPM have exactly the same perspective, but GEO and TPM have different methods for calculating their respective weight tables. This example coordinates TPM weight calculations by using the same derivation method as GEO.

[0260] In the syntactic representation, GEO can produce the same predictions as TPM for a given CU size and angle pair. This syntax overhead is removed: that is, GEO does not support edges located in the diagonal direction (i.e., edges connected by two opposite corners within a CU).

[0261] Figure 21 is a flowchart illustrating example operations for decoding video data according to one or more techniques of this disclosure. Figure 21 technology, the universal video decoder may correspond to the video decoder 300, for example. Figure 21 The technique can also be performed by the decoding loop of the video encoder 200 as part of the video encoding process. Figure 21 As seen in the example of FIG, a video decoder may initially determine that a block of video data is encoded in a geometric partitioning mode (400). The video decoder may determine an angle for the block of video data in the geometric partitioning mode (410). To determine the angle for the block of video data in the geometric partitioning mode, the video decoder may, for example, determine the angle from a set of available angles that only includes angles having a tangent value equal to 2. n where n is an integer value representing a power of 2.

[0262] Next, the video decoder may determine a partition line displacement relative to a center of the block of the geometric partitioning pattern (420). Next, the video decoder may determine a first prediction sample for the block of video data using the motion vector of the first partition (430). The video decoder may determine a second prediction sample for the block of video data using the motion vector of the second partition (440).

[0263] Next, the video decoder may determine a power of 2 based on the angle of the block of video data (450). The power of 2 represents a value equal to 2. n where n represents an integer value. For example, the integer value can be between -4 and 4, although other integer values can also be used. Powers of 2 generally correspond to the tangent of an angle or its approximation.

[0264] Next, the video decoder may determine a weight value based on a power of 2 (460). To determine the weight value based on a power of 2, the video decoder may apply a shift operation based on a power of 2. To determine the weight value based on a power of 2, the video decoder 300 may be configured to apply a shift operation based on a power of 2 to determine a distance value and determine the weight value based on the distance value. To determine the weight value based on the distance value, the video decoder may be configured to determine the weight value from a lookup table.

[0265] Next, the video decoder may perform a blending operation on the first prediction samples and the second prediction samples based on the weight value to determine a prediction block for the block of video data (470). To perform the blending operation on the first prediction samples and the second prediction samples to determine the prediction block for the block of video data, the video decoder may be configured to determine a weighted average of samples in the first prediction samples and samples in the second prediction samples to determine sample values of the prediction block samples, wherein the weight value corresponds to a weight used to determine the weighted average.

[0266] The video decoder may output the prediction block (480).For example, the video decoder may determine residual data indicating a difference between the prediction block and the block of video data and reconstruct the block of video data by adding the prediction block and the residual data.

[0267] It should be appreciated that, depending on the example, certain actions or events of any technique described herein may be performed in a different order, may be added, combined, or omitted altogether (e.g., not all described actions or events are required for practice of the technique). Furthermore, in some examples, actions or events may be performed concurrently, e.g., through multithreading, interrupt handling, or multiple processors, rather than sequentially.

[0268] The following examples are illustrative of the techniques and devices described above.

[0269] Example 1. A method for encoding and decoding video data, the method comprising encoding and decoding a current picture using a geometric partitioning mode according to any one or a combination of the techniques described in this disclosure.

[0270] Example 2. The method of Example 1, wherein encoding and decoding includes decoding.

[0271] Example 3. The method of example 1, wherein encoding and decoding includes encoding.

[0272] Example 4. A device for encoding and decoding video data, the device comprising: a memory configured to store the video data; and a processing circuit configured to encode and decode a current picture using a geometric partitioning mode according to any one or combination of the techniques described in this disclosure.

[0273] Example 5. The apparatus according to Example 4, further comprising a display configured to display the decoded video data.

[0274] Example 6. The device of any of Examples 4 and 5, wherein the device comprises one or more of a camera, a computer, a mobile device, a broadcast receiver device, or a set-top box.

[0275] Example 7. The device of any of Examples 4-6, wherein the device comprises a video decoder.

[0276] Example 8. The apparatus of any of Examples 5-6, wherein the apparatus comprises a video encoder.

[0277] Example 9. A computer-readable storage medium having instructions stored thereon that, when executed, cause one or more processors to encode or decode a current picture using a geometric partitioning mode according to any one or combination of the techniques described in this disclosure.

[0278] Example 10. A device for encoding and decoding video data, the device comprising means for encoding and decoding a current picture using a geometric partitioning mode according to any one or combination of the techniques described in this disclosure.

[0279] In one or more examples, the functions described may be implemented in hardware, software, firmware, or any combination thereof. If implemented in software, the functions may be stored on or transmitted via a computer-readable medium as one or more instructions or codes and executed by a hardware-based processing unit. Computer-readable media may include computer-readable storage media, which corresponds to tangible media such as data storage media, or communication media including, for example, any medium that facilitates the transfer of a computer program from one place to another according to a communication protocol. In this manner, computer-readable media may generally correspond to (1) non-transitory, tangible computer-readable storage media or (2) communication media such as signals or carrier waves. Data storage media may be any available media that can be accessed by one or more computers or one or more processors to retrieve instructions, codes, and / or data structures for implementing the techniques described in this disclosure. A computer program product may include computer-readable media.

[0280] As an example and not limitation, such computer-readable storage media may include RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, flash memory, or any other medium that can be used to store the required program code in the form of instructions or data structures and can be accessed by a computer. In addition, any connection is appropriately referred to as a computer-readable medium. For example, if a coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL) or wireless technologies such as infrared, radio and microwaves are used to send instructions from a website, server or other remote source, then the coaxial cable, fiber optic cable, twisted pair, DSL or wireless technologies such as infrared, radio and microwaves are included in the definition of the medium. However, it should be understood that computer-readable storage media and data storage media do not include connections, carrier waves, signals or other temporary media, but rather refer to non-temporary tangible storage media. The disks and optical disks used herein include compact discs (CDs), laser discs, optical discs, digital versatile discs (DVDs), floppy disks and Blu-ray discs, wherein disks typically reproduce data magnetically, while optical discs reproduce data optically with lasers. The above combinations should also be included within the scope of computer-readable media.

[0281] Instructions may be executed by one or more processors such as one or more digital signal processors (DSPs), general-purpose microprocessors, application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other equivalent integrated or discrete logic circuits. Thus, the term "processor," as used herein, may refer to any of the aforementioned structures or any other structure suitable for implementing the techniques described herein. Additionally, in some aspects, the functionality described herein may be provided within dedicated hardware and / or software modules configured for encoding and decoding, or incorporated into a combined codec. Furthermore, these techniques may be fully implemented in one or more circuits or logic elements.

[0282] The techniques of this disclosure can be implemented in a variety of devices or apparatuses, including wireless handheld devices, integrated circuits (ICs), or IC sets (e.g., chipsets). Various components, modules, or units are described in this disclosure to emphasize the functional aspects of devices configured to perform the disclosed techniques, but do not necessarily need to be implemented by different hardware units. Instead, as described above, the various units can be combined in a codec hardware unit, or provided by a collection of interoperable hardware units including one or more processors as described above in combination with appropriate software and / or firmware.

[0283] Various examples have been described. These and other examples are within the scope of the following claims.

Claims

1. A method for decoding video data, the method comprising: determining that the block of the video data is encoded in a geometric partitioning mode; Determining an angle for the block of video data for the geometric partitioning mode, wherein determining the angle for the block of video data for the geometric partitioning mode comprises: determining the angle from a set of available angles, wherein the set of available angles comprises a plurality of angles having a value equal to 2. n The angle of the tangent or cotangent of , where n represents an integer value; determining a partitioning line displacement relative to a center of the block of the geometric partitioning pattern; dividing the block into a first partition and a second partition based on the angle and the partition line displacement; determining a first prediction sample for the block of the video data using a motion vector for the first partition; determining a second prediction sample for the block of the video data using the motion vector of the second partition; determining a power of two based on the angle of the block of the video data; Determining a weight value based on the power of 2; performing a blending operation on the first prediction samples and the second prediction samples based on the weight values to determine a prediction block for the block of the video data; and The predicted block is output.

2. The method according to claim 1, wherein The power of 2 is equal to 2 n , where n represents an integer value.

3. The method according to claim 2, wherein: n represents an integer value between -4 and 4.

4. The method according to claim 1, wherein The power of 2 includes the tangent of the angle.

5. The method according to claim 1, wherein Determining the weight value based on the power of 2 includes applying a shift operation based on the power of 2, wherein a multiplication for each sample point is replaced by a bit shift operation.

6. The method according to claim 1, wherein Determining the weight value based on the power of 2 includes: applying a shift operation based on the power of 2 to determine a distance value, wherein a multiplication for each sample point is replaced by a bit shift operation; and The weight value is determined based on the distance value.

7. The method according to claim 6, wherein: Determining the weight value based on the distance value includes determining the weight value from a lookup table.

8. The method according to claim 1, wherein Performing a blending operation on the first prediction samples and the second prediction samples to determine a prediction block for the block of video data includes determining a weighted average of samples in the first prediction samples and samples in the second prediction samples to determine sample values of the samples of the prediction block, wherein the weight value includes a weight used to determine the weighted average.

9. The method according to claim 1, further comprising: receiving residual data indicating a difference between the prediction block and the block of the video data; as well as The block of the video data is reconstructed by adding the prediction block and the residual data.

10. The method according to claim 1, wherein The encoding method is performed as part of a video encoding process.

11. A device for decoding video data, the device comprising: a memory configured to store video data; One or more processors implemented in circuitry and configured to: determining that the block of the video data is encoded in a geometric partitioning mode; determining an angle of the block of video data for the geometric partitioning mode, wherein to determine the angle of the block of video data for the geometric partitioning mode, the one or more processors are further configured to: determine the angle from a set of available angles, wherein the set of available angles consists only of angles having a value equal to 2 n The angle of the tangent value of , where n represents an integer value; determining a partitioning line displacement relative to a center of the block of the geometric partitioning pattern; dividing the block into a first partition and a second partition based on the angle and the partition line displacement; determining a first prediction sample for the block of the video data using a motion vector for the first partition; determining a second prediction sample for the block of the video data using the motion vector of the second partition; determining a power of two based on the angle of the block of the video data; Determining a weight value based on the power of 2; performing a blending operation on the first prediction samples and the second prediction samples based on the weight values to determine a prediction block for the block of the video data; and The predicted block is output.

12. The apparatus according to claim 11, wherein The power of 2 is equal to 2 n , where n represents an integer value.

13. The apparatus according to claim 12, wherein n represents an integer value between -4 and 4.

14. The apparatus according to claim 11, wherein The power of 2 includes the tangent of the angle.

15. The apparatus according to claim 11, wherein To determine the weight value based on the power of 2, the one or more processors are further configured to apply a shift operation based on the power of 2, wherein a multiplication for each sample is replaced by a bit shift operation.

16. The apparatus according to claim 11, wherein In order to determine the weight value based on the power of 2, the one or more processors are further configured to: applying a shift operation based on the power of 2 to determine a distance value, wherein a multiplication for each sample point is replaced by a bit shift operation; and The weight value is determined based on the distance value.

17. The apparatus according to claim 16, wherein To determine the weight value based on the distance value, the one or more processors are further configured to: determine the weight value from a lookup table.

18. The apparatus according to claim 11, wherein To perform a blending operation on the first prediction samples and the second prediction samples to determine a prediction block for the block of video data, the one or more processors are further configured to determine a weighted average of samples from the first prediction samples and samples from the second prediction samples to determine sample values for the samples of the prediction block, wherein the weight values include weights used to determine the weighted average.

19. The apparatus according to claim 11, wherein The one or more processors are further configured to: receiving residual data indicative of a difference between the prediction block and the block of the video data; and The block of the video data is reconstructed by adding the prediction block and the residual data.

20. The apparatus according to claim 11, wherein The device is configured to output the prediction block as part of a video encoding process.

21. The apparatus according to claim 11, wherein The apparatus comprises a wireless communication device and also includes a receiver configured to receive encoded video data.

22. The apparatus according to claim 21, wherein The wireless communication device comprises a telephone handset, and wherein the receiver is configured to demodulate a signal comprising the encoded video data in accordance with a wireless communication standard.

23. The apparatus of claim 11, further comprising: A display is configured to display decoded video data determined according to the prediction block.

24. The apparatus of claim 11, wherein The device includes one or more of a camera, a computer, a mobile device, a broadcast receiver device, or a set-top box.

25. An apparatus for decoding video data, the apparatus comprising: means for determining that a block of said video data is encoded in a geometric partitioning mode; means for determining an angle of the block of video data for the geometric partitioning mode, wherein said means for determining the angle of the block of video data for the geometric partitioning mode comprises: means for determining the angle from a set of available angles, wherein said set of available angles consists only of angles having a value equal to 2 n The angle of the tangent value of , where n represents an integer value; means for determining a displacement of a partitioning line relative to a center of said block of said geometric partitioning pattern; means for dividing the block into a first partition and a second partition based on the angle and the partition line displacement; means for determining a first prediction sample for the block of the video data using a motion vector for the first partition; means for determining a second prediction sample for the block of the video data using the motion vector of the second partition; means for determining a power of two based on the angle of the block of the video data; means for determining a weight value based on the power of 2; means for performing a blending operation on the first prediction samples and the second prediction samples based on the weight values to determine a prediction block for the block of the video data; and means for outputting said prediction block.

26. The device according to claim 25, wherein The power of 2 is equal to 2 n , where n represents an integer value.

27. The device according to claim 26, wherein n represents an integer value between -4 and 4.

28. The apparatus of claim 25, wherein the power of 2 comprises a tangent of the angle.

29. The apparatus according to claim 25, wherein The means for determining the weight value based on the power of 2 comprises means for applying a bit shift operation based on the power of 2, wherein a multiplication for each sample point is replaced by a bit shift operation.

30. The apparatus of claim 25, wherein: The component for determining the weight value based on the power of 2 includes: means for applying a bit shift operation based on said power of 2 to determine a distance value, wherein a multiplication for each sample point is replaced by a bit shift operation; and means for determining said weight value based on said distance value.

31. The device according to claim 30, wherein The means for determining the weight value based on the distance value includes means for determining the weight value from a lookup table.

32. The apparatus according to claim 25, wherein The means for performing a blending operation on the first prediction samples and the second prediction samples to determine a prediction block for the block of video data includes means for determining a weighted average of samples from the first prediction samples and samples from the second prediction samples to determine sample values of the samples of the prediction block, wherein the weight value includes a weight for determining the weighted average.

33. The apparatus of claim 25, further comprising: means for receiving residual data indicative of a difference between said prediction block and said block of said video data; as well as Means for reconstructing the block of video data by adding the prediction block and the residual data.

34. A computer-readable storage medium storing instructions that, when executed by one or more processors, cause the one or more processors to: Determining that a block of video data is encoded in a geometric partitioning mode; determining an angle for the block of video data for the geometric partitioning pattern, wherein To determine the angle of the block of video data for the geometric partitioning mode, the one or more processors are further configured to: determine the angle from a set of available angles, wherein the set of available angles consists only of angles having a value equal to 2 n The angle of the tangent value of , where n represents an integer value; determining a partitioning line displacement relative to a center of the block of the geometric partitioning pattern; dividing the block into a first partition and a second partition based on the angle and the partition line displacement; determining a first prediction sample for the block of the video data using a motion vector for the first partition; determining a second prediction sample for the block of the video data using the motion vector of the second partition; determining a power of two based on the angle of the block of the video data; Determining a weight value based on the power of 2; performing a blending operation on the first prediction samples and the second prediction samples based on the weight values to determine a prediction block for the block of the video data; and The predicted block is output.

35. The computer-readable storage medium of claim 34, wherein: The power of 2 is equal to 2 n , where n represents an integer value.

36. The computer-readable storage medium of claim 35, wherein: n represents an integer value between -4 and 4.

37. The computer-readable storage medium of claim 34, wherein: The power of 2 includes the tangent of the angle.

38. The computer-readable storage medium of claim 34, wherein: To determine the weight value based on the power of 2, the one or more processors are further configured to apply a shift operation based on the power of 2, wherein a multiplication for each sample is replaced by a bit shift operation.

39. The computer-readable storage medium of claim 34, wherein: In order to determine the weight value based on the power of 2, the one or more processors are further configured to: applying a shift operation based on the power of 2 to determine a distance value, wherein a multiplication for each sample point is replaced by a bit shift operation; and The weight value is determined based on the distance value.

40. The computer-readable storage medium of claim 39, wherein: To determine the weight value based on the distance value, the one or more processors are further configured to: determine the weight value from a lookup table.

41. The computer-readable storage medium of claim 34, wherein: To perform a blending operation on the first prediction samples and the second prediction samples to determine a prediction block for the block of video data, the one or more processors are further configured to determine a weighted average of samples from the first prediction samples and samples from the second prediction samples to determine sample values for the samples of the prediction block, wherein the weight values include weights used to determine the weighted average.

42. The computer-readable storage medium of claim 34, wherein: The one or more processors are further configured to: receiving residual data indicative of a difference between the prediction block and the block of the video data; and The block of the video data is reconstructed by adding the prediction block and the residual data.

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