Referencing neighboring reconstruction samples in overlapped block motion compensation

Abstract

A method of coding video data comprises performing motion compensation using motion information of a current block to generate a first predictor; performing overlapped block motion compensation (OBMC) to generate a second predictor based on the first predictor; deriving local illumination compensation (LIC) parameters based on neighboring reconstructed samples; after performing OBMC, applying the LIC parameters to the second predictor to generate a third predictor for the current block; and encoding or decoding the current block based on the third predictor.

Description

REFERENCING NEIGHBORING RECONSTRUCTION SAMPLES IN OVERLAPPED BLOCK MOTION COMPENSATION100011 This application claims the benefit of U.S. Provisional Patent Application 63 / 716,086, filed November 4, 2024, the entire content of which is incorporated by reference.TECHNICAL FIELD

[0002] This disclosure relates to video encoding and video decoding.BACKGROUND

[0003] 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 gaming devices, video game consoles, cellular or satellite radio telephones, so-called “smart phones,” video teleconferencing devices, video streaming devices, and the like. Digital video devices implement video coding techniques, 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 Coding (AVC), ITU-T H.265 / High Efficiency Video Coding (HE VC), ITU-T H.266 / Versatile Video Coding (VVC), and extensions of such standards, as well as proprietary video codecs / formats such as AOMedia Video 1 (AV1) that was developed by the Alliance for Open Media. The video devices may transmit, receive, encode, decode, and / or store digital video information more efficiently by implementing such video coding techniques.

[0004] 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) may be partitioned into video blocks, which may 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 with respect to reference samples in neighboring blocks in the same picture. Video blocks in an inter-coded (P or B) slice of a picture may use spatial prediction with respect to reference samples in neighboring blocks in the same picture or temporal prediction with respect to reference samples inother reference pictures. Pictures may be referred to as frames, and reference pictures may be referred to as reference frames.SUMMARY

[0005] In existing codecs, inter prediction is typically performed before intra prediction as a different pass so that the motion compensation process can be completed earlier and therefore be ready for reconstruction. When local illumination compensation (LIC) is applied with overlapped block motion compensation (OBMC), LIC is applied to a motion compensated signal of a current block using motion information of the current block, then OBMC is performed on the output of LIC. However, LIC references the neighboring reconstruction samples to derive the LIC parameters. Hence, in existing codecs, OBMC is performed after neighboring reconstructed samples are ready, or at least the generation of OBMC-modified prediction samples need to wait for the neighbouring reconstructed samples to be ready. Similarly, when intra prediction is used in the OBMC process for block boundaries, the existing codecs can only generate the OBMC -modified prediction samples after neighboring blocks are reconstructed. Especially when inner subblock OBMC is applied for subblock boundaries presented in the block, inner subblock OBMC is performed after boundary OBMC is finished. Such dependency may cause significant delay in hardware decoding.

[0006] This disclosure describes techniques that address these problems. In general, this disclosure describes techniques for OBMC. Referencing neighboring reconstructed samples when intra prediction or LIC is performed with OBMC may introduce delays. This disclosure describes techniques in which LIC with OBMC and intra prediction with OBMC are designed such that the inter prediction related process (in other words, process that invokes motion compensation) in OBMC can be done earlier without needing to wait for the neighboring reconstructed samples to be ready. As described herein, a video coder references neighboring reconstructed samples when LIC or intra prediction is used. However, in accordance with the techniques of this disclosure, the referencing of the neighboring reconstructed samples is moved to a later stage compared to current designs. In some examples, the referencing of the neighboring reconstructed samples is moved to the last stage of prediction sample generation (after OBMC or in the last step of OBMC), such that the other inter prediction related process in OBMC are performed earlier and would not need to wait for neighboring reconstructed samples to be ready.

[0007] In one example, this disclosure describes a method of coding video data, the method comprising: performing motion compensation using motion information of a current block to generate a first predictor; performing inner subblock overlapped-block motion compensation (OBMC) to generate a second predictor for the current block based on the first predictor; using motion information of one or more neighboring blocks to perform motion compensation and perform blending with the second predictor to generate a third predictor for the current block; applying local illumination compensation (LIC) parameters to the third predictor to generate a fourth predictor for the Current block; and encoding or decoding the current block based on the fourth predictor for the current block.

[0008] In another example, this disclosure describes a method of coding video data, the method comprising: performing motion compensation using motion information of a current block to generate a first predictor; performing inner subblock overlapped-block motion compensation (OBMC) to generate a second predictor for the current block based on the first predictor; using motion information of one or more neighboring blocks to perform motion compensation and perform blending with the second predictor to generate a third predictor for the current block; performing intra prediction using intra prediction information of one or more neighboring blocks and blending with the third predictor to generate a fourth predictor for the current block; and encoding or decoding the current block based on the fourth predictor for the current block.

[0009] In another example, this disclosure describes a method of coding video data, the method comprising: performing motion compensation using motion information of a current block to generate a first predictor; performing inner subblock overlapped-block motion compensation (OBMC) to generate a second predictor for the current block based on the first predictor; using motion information of one or more neighboring blocks to perform motion compensation and blending with the second predictor to generate a third predictor for the current block; applying local illumination compensation (LIC) parameters to the third predictor to generate a fourth predictor for the current block; performing intra prediction using intra prediction information of one or more neighboring blocks and blending with the fourth predictor to generate a fifth predictor; and encoding or decoding the current block based on the fifth predictor for the current block.

[0010] In another example, this disclosure describes a method of coding video data, the method comprising: performing motion compensation using motion information of a current block to generate a first predictor; performing overlapped block motion compensation (OBMC) to generate a second predictor based on the first predictor;deriving local illumination compensation (LIC) parameters based on neighboring reconstructed samples; after performing OBMC, applying the LIC parameters to the second predictor to generate a third predictor for the current block; and encoding or decoding the current block based on the third predictor,(0011] In another example, this disclosure describes a device for coding video data, the device comprising: a memory; and one or more processors configured to cause the device to: perform motion compensation using motion information of a current block to generate a first predictor; perform overlapped block motion compensation (OBMC) to generate a second predictor based on the first predictor; derive local illumination compensation (LIC) parameters based on neighboring reconstructed samples; after performing OBMC, applying the LIC parameters to the second predictor to generate a third predictor for the current block; and encode or decode the current block based on the third predictor. (0012] In another example, this disclosure describes, a non-transitory computer-readable storage medium having stored thereon instructions that, when executed, cause one or more processors to: perform motion compensation using motion information of a current block to generate a first predictor; perform overlapped block motion compensation (OBMC) to generate a second predictor based on the first predictor; derive local illumination compensation (LIC) parameters based on neighboring reconstructed samples; after performing OBMC, apply the LIC parameters to the second predictor to generate a third predictor for the current block; and encode or decode the current block based on the third predictor.

[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 DRAWINGS

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

[0015] FIG. 2 illustrates an example of an overlapped block motion compensation (OBMC) extension with intra prediction, showing how boundary pixels adjacent to intra blocks are processed.

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

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

[0018] FIG. 5 is a flowchart illustrating an example method for encoding a current block in accordance with the techniques of this disclosure,

[0019] FIG. 6 is a flowchart illustrating an example method for decoding a current block in accordance with the techniques of this disclosure.

[0020] FIG. 7 is a conceptual diagram illustrating an example of an overlapped block motion compensation extension with local illumination compensation (LIC), in accordance with one or more techniques of this disclosure.

[0021] FIG. 8 is a conceptual diagram illustrating an example of an overlapped block motion compensation extension with intra prediction, in accordance with one or more techniques of this disclosure,

[0022] FIG. 9 is a flowchart illustrating an example operation for OBMC with LIC and intra prediction, in accordance with one or more techniques of this disclosure.DETAILED DESCRIPTION

[0023] This disclosure describes techniques for overlapped block motion compensation (OBMC). In general, OBMC involves using motion information of a current block to generate an initial motion-compensated predictor for the current block. In addition, the OBMC involves using motion information of neighboring blocks to generate a second predictor for the current block. Boundary samples of a block are samples adjacent to a top or left boundary of the block. A blended predictor is then generated based on a weighting function of sample values in the first and second predictors. In some examples, the first predictor and the second predictor are only used in boundary subblocks of the current block (i.e., subblocks of the current block that are adjacent to top and left boundaries of the current block) and the first predictor alone is used for inner subblocks of the current block (i.e., subblocks of the current block that are not adjacent to the top and left boundaries of the current block) In some examples, the initial motion-compensated predictor and one or more secondary predictors are used for inner subblocks of the current block. The term inner subblock OBMC is used to refer to cases in which the initial motion-compensated predictor and secondary predictors are used to generate blended predictors for internal subblocks. In some examples, a current block is coded with a subblock-based method. The subblock-based method may be affine prediction, subblock-based temporal motion vector prediction (sbTMVP), decoder-side motion vector refinement (DMVR) or bidirectional optical flow (BDOF) based subblock motion derivation. When a subblock-based method is used, the current block is split into a group of subblocks. Each subblock within the current block is associated with its own set of motion information. Inner subblock OBMC performs OBMC on those subblock boundaries. That is, for each subblock, inner subblock OBMC uses the associated motion information of the subblock to generate the initial motion-compensated first predictor and uses the motion information from the adjacent subblock(s) to generate the second predictor, the inner subblock OBMC then blends the first predictor with the second predictor to generate inner subblock OBMC modified prediction samples for the subblock.

[0024] A video encoder may use the blended predictor (i.e,, the OBMC modified prediction samples) and original sample values of the current block to generate residual data for the current block. A video decoder may use the blended predictor and residual data to reconstruct sample values of the current block.

[0025] If a boundary subblock of the current block is adjacent to a neighboring intra block (i.e., an intra-adjacent boundary subblock), corresponding samples in the blended predictor are generated based only on the initial motion-compensated predictor. This can result in a discontinuity in the blended predictor at the boundary subblock. To address this, OBMC was extended to use intra prediction. A decoder-side intra mode derivation (DIMD) process is used by the video encoder and the video decoder to determine an intra prediction mode for the current block. The DIMD process determines the intra prediction mode based on reconstructed neighboring samples above and left of the current block. The determined intra prediction inode is then used to perform intra prediction to generate an intra predictor for the current block. Samples of the blended predictor corresponding to the intra-adjacent boundary subblock are determined based on the initial motion-compensated predictor and the intra predictor.

[0026] In hardware video codecs, inter prediction is typically done before intra prediction as a different pass so that the complex motion compensation process can be done earlier and motion compensated signals are ready for the reconstruction. Local illumination compensation (LIC) is a technique to correct for the effects of uneven lighting between pictures. Such uneven lighting may be caused by changes in overall illumination levels, objects passing into or out of shadows, and so on, In a current version of the Enhanced Compression Model (ECM), when LIC is applied with OBMC, LIC is performed on topof motion compensated signals using the motion information of the current block, then OBMC is performed on top of the output of LIC. In other words, motion compensation is performed to generate motion compensated signals, LIC is applied to the motion compensated signals to generate illumination compensated signals, and then OBMC is applied using the illumination compensated signals.(0027] However, in the current version of ECM, the LIC process uses the neighboring reconstru cted samples to derive parameters that control the adjustments to samples of the motion compensated signals. Thus, using the neighboring reconstructed samples to derive the parameters requires OBMC to be performed after the neighboring reconstruction samples are ready. Similarly, in the current version of ECM, intra prediction in OBMC relies on reconstructed samples of neighboring blocks and he nce needs to be performed after the neighboring blocks are reconstructed. This reliance on reconstructed samples of neighboring blocks especially applies when inner subblock OBMC is applied because inner block OBMC is performed after the boundary OBMC is finished. Such dependencies on reconstructed samples cause significant delays in hardware decoding. In other words, referencing neighboring reconstructed samples when intra prediction or LIC is performed with OBMC may introduce delays.

[0028] The techniques of this disclosure may address this issue. This disclosure describes techniques in which LIC with OBMC and intra prediction with OBMC are designed such that the inter prediction related process in OBMC can be done before referencing the neighboring reconstructed samples. As described herein, a video coder (e.g., a video encoder or a video decoder) may perform motion compensation using motion information of a current block to generate a first predictor. Additionally, the video coder may perform overlapped-block motion compensation (OBMC) to generate a second predictor for the current block based on the first predictor. The video coder may derive local illumination compensation (LIC) parameters based on neighboring reconstructed samples and apply the LIC parameters to the second predictor to generate a third predictor for the current block. The video coder may encode or decode the cunent block based on the third predictor for the current block. In some examples, the video coder may perform motion compensation using motion information of a current block to generate a first predictor. Additionally, the video coder may perform OBMC to generate a second predictor for the current block based on the first predictor. The video coder may perform intra prediction using intra prediction information of one or more neighboring blocks to generate a third predictor for the current block. The video coder may encode or decode the current blockbased on the third predictor for the current block. Thus, unlike the current version of ECM, the video coder performs OBMC based on a predictor generated using motion compensation and not reconstructed samples. Because the video coder performs OBMC based on this predictor and not reconstructed samples, the video coder may avoid the delays associated with waiting for determination of the reconstructed samples. Consequently, the process of encoding and decoding video data may be accelerated.

[0029] FIG. 1 is a block diagram illustrating an example video encoding and decoding system 100 that may perform the techniques of this disclosure. The techniques of this disclosure are generally directed to coding (encoding and / or decoding) video data. In general, video data includes any data for processing a video. Thus, video data may include raw, unencoded video, encoded video, decoded (e.g., reconstructed) video, and video metadata, such as signaling data.

[0030] As shown in FIG. I, system 100 includes a source device 102 that provides encoded video data to be decoded and displayed by a destination device 116, in this example. 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 be or include any of a wide range of devices, such as 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 gaming consoles, video streaming device, broadcast receiver devices, or the like. In some cases, source device 102 and destination device 116 may be equipped for wireless communication, and thus may be referred to as wireless communication devices.

[0031] In the example of FIG. 1, source device 102 includes video source 104, memory 106, video encoder 200, and output interface 108. Destination device 116 includes input interface 122, video decoder 300, memory 120, and display device 118. In accordance with this disclosure, video encoder 200 of source device 102 and video decoder 300 of destination device 116 may be configured to apply the techniques for overlapped block motion compensation. 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, a source device and a destination device may include other components or arrangements. For example, source device 102 may receive video data from an external video source, such as an external camera. Likewise, destination device 116 may interface with an external display device, rather than include an integrated display device.

[0032] System 100 as shown in FIG. 1 is merely one example. In general, any digital video encoding and / or decoding device may perform techniques for overlapped block motion compensation. Source device 102 and destination device 116 are merely examples of such coding devices in which source device 102 generates coded video data for transmission to destination device 116. This disclosure refers to a “coding” device as a device that performs coding (encoding and / or decoding) o f data. Thus, video encoder 200 and video decoder 300 represent examples of coding devices, in particular, a video encoder and a video decoder, respectively. In some examples, source device 102 and destination device 116 may operate in a substantially symmetrical manner such that each of source device 102 and destination device 116 includes video encoding and decoding components. Hence, system 100 may support one-way or two-way video transmission between source device 102 and destination device 116, e.g., for video streaming, video playback, video broadcasting, or video telephony.

[0033] In general, video source 104 represents a source of video data (i.e., raw, unencoded video data) and provides a sequential series of pictures (also referred to as “frames'”) of the video data to video encoder 200, which encodes data for the pictures. Video source 104 of source device 102 may include a video capture device, such as a video camera, a video archive containing previously captured raw video, and / or a video feed interface to receive 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 the captured, pre-captured, or computer-generated video data. Video encoder 200 may rearrange the pictures from the received order (sometimes referred to as “display order”) into a coding order for coding. Video encoder 200 may generate a bitstream including encoded video data. Source device 102 may then output the encoded video data via output interface 108 onto computer-readable medium 110 for reception and / or retrieval by, e.g., input interface 122 of destination device 116.

[0034] Memory 106 of source device 102 and memory 120 of destination device 116 represent general purpose memories. In some examples, memories 106, 120 may 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, 120 may store software instructions executable by, e.g., 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 200and video decoder 300 may also include internal memories for functionally similar or equivalent purposes. Furthermore, memories 106, 120 may store encoded video data, e.g., output from video encoder 200 and input to video decoder 300. In some examples, portions of memories 106, 120 may be allocated as one or more video buffers, e.g., to store raw, decoded, and / or encoded video data.

[0035] Computer-readable medium 110 may represent any type of medium or device capable of transporting the encoded video data from source device 102 to destination device 116. In one example, computer-readable medium 110 represents a communication medium to enable source device 102 to transmit encoded video data directly to destination device 116 in real-time, e.g., via a radio frequency network or computer-based network. Output interface 108 may modulate a transmission signal including the encoded video data, and input interface 122 may demodulate the received transmission signal, according to a communication standard, such as a wireless communication protocol. The communication medium may include any wireless or wired communication medium, such as a radio frequency (RF) spectrum or one or more physical transmission lines. The communication medium may 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 may include routers, switches, base stations, or any other equipment that may be useful to facilitate communication from source device 102 to destination device 116.

[0036] In some examples, source device 102 may output encoded data from output interface 108 to storage device 112. Similarly, destination device 116 may access 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 discs, DVDs, CD-ROMs, flash memory, volatile or non-volatile memory, or any other suitable digital storage media for storing encoded video data.

[0037] In some examples, source device 102 may output 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 stored video data from file server 114 via streaming or download.

[0038] File server 114 may be any type of server device capable of storing encoded video data and transmitting that encoded video data to the destination device 116. File server 114 may represent a web server (e.g., for a website), a server configured to provide a file transfer protocol service (such as File Transfer Protocol (FTP) or File Delivery overHUnidirectional Transport (FLUTE) protocol), a content delivery' network (CDN) device, a hypertext transfer protocol (HTTP) server, a Multimedia Broadcast Multicast Sendee (MBMS) or Enhanced MBMS (eMBMS) server, and / or a network attached storage (NAS) device. File server 11.4 may, additionally or alternatively, 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, or the like.

[0039] Destination device 116 may access encoded video data from file server 114 through any standard data connection, including an Internet connection. This may include a wireless channel (e.g., a Wi-Fi connection), a wired connection (e.g., digital subscriber line (DSL), cable modem, etc.), or a combination of both that is suitable for accessing encoded video data stored on file server 114. Input interface 122 may 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.

[0040] Output interface 108 and input interface 122 may represent wireless transniitters / receivers, modems, wired networking components (e.g., Ethernet cards), wireless communication components that operate according to any of a variety of IEEE 802.11 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 transfer data, such as encoded video data, according to a cellular communicationstandard, such as 4G, 4G-LTE (Long-Term Evolution), LTE Advanced, 5G, or the like. In some examples where output interface 108 includes a wireless transmitter, output interface 108 and input interface 122 may be configured to transfer data, such as encoded video data, according to other wireless standards, such as an IEEE 802.11 specification, an IEEE 802.15 specification (e.g., ZigBee™), a Bluetooth™ standard, or the like. In some examples, source device 102 and / or destination device 116 may incl tide respective system-on~a-chip (SoC) devices. For example, source device 102 may include an SoC device to perform the functionality attributed to video encoder 200 and / or output interface 108, and destination device 11 may include an SoC device to perform the functionality attributed to video decoder 300 and / or input interface 122.

[0041] The techniques of thi s disc losure may be appli ed to video coding in support of any of a variety of mul timedia applications, such as over-the-air television broadcasts, cabletelevision transmissions, satellite television transmissions, Internet streaming video transmissions, such as dynamic adaptive streaming over HTTP (DASH), digital video that is encoded onto a data storage medium, decoding of digital video stored on a data storage medium, or other applications.

[0042] Input interface 122 of destination device 116 receives an encoded video bitstream from computer-readable medium 110 (e.g., a communication medium, storage device 112, file server 114, or the like). The encoded video bitstream may include signaling information defined by video encoder 200, which is also used by video decoder 300, such as syntax elements having values that describe characteristics and / or processing of video blocks or other coded units (e.g., slices, pictures, groups of pictures, sequences, or the like). Display device 118 displays decoded pictures of the decoded video data to a user. 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.

[0043] Although not shown in FIG. 1, in some examples, video encoder 200 and video decoder 300 may each be integrated with an audio encoder and / or audio decoder (e.g., audio codec), and may include appropriate MUX-DEMUX units, or other hardware and / or software, to handle multiplexed streams including both audio and video in a common data stream. Example audio codecs may include AAC, AC-3, AC-4, AI. AC, ALS, AMBE, AMR, AMR-WB (G.722.2), AMR-WB+, aptx (various versions), ATRAC, Broad Voice (BV16, BV32), CELT, Enhanced AC-3 (E-AC-3), EVS, FLAG, G.711, G.722, G.722.1, G.722.2 (AMR-WB). G.723.1, G.726, G.728, G.729, 0.729.1, GSM-FR, HE- AAC, iLBC, iSAC, LA Lyra, Monkey's Audio, MPL MP2 (MPEG- 1, 2 Audio Layer II), MP3, Musepack, Nellyrnoser Asao, OptimFROG, Opus, Sac, Satin, SBC, SILK, Siren 7, Speex, SVOPC, True Audio (TTA), TwinVQ, US AC, Vorbis (Ogg), WavPack, and Windows Media Aud,

[0044] Video encoder 200 and video decoder 300 each may be implemented as any of a variety of suitable encoder and / or decoder circuitry that includes a processing system, such as one or more microprocessors, digital signal processors (DSPs), application specific integrated circuits (ASICs), field programmable gate arrays (FPG As), discrete logic, software, hardware, firmware or any combinations thereof "When the techniques are implemented partially in software, a device may store instructions for the software in a suitable, non-transitor computer-readable medium and execute the instructions in hard ware using one or more processors to perform the techniques of this disclosure. Eachof video encoder 200 and video decoder 300 may be included in one or more encoders or decoders, either of which may be integrated as part of a combined encoder / decoder (CODEC) in a respective device, A device including video encoder 200 and / or video decoder 300 may implement video encoder 200 and / or video decoder 300 in processing circuitry such as an integrated circuit and / or a microprocessor. Such a device may be a wireless communication device, such as a cellular telephone, or any other type of device described herein,(0045] Video encoder 200 and video decoder 300 may operate according to a video coding standard, such as ITU-T 1-1.265, also referred to as High Efficiency Video Coding (HEVC) or extensions thereto, such as the multi-view and / or scalable video coding extensions. Alternatively, video encoder 200 and video decoder 300 may operate according to other proprietary or industry standards, such as ITU-T H.266, also referred to as Versatile Video Coding (VVC). In other examples, video encoder 200 and video decoder 300 may operate according to a proprietary video codec / format, such as AOMedia Video 1 (AVI), extensions of AVI, and / or successor versions of AVI (e.g., AV2). In other examples, video encoder 200 and video decoder 300 may operate according to other proprietary formats or industry standards. The techniques of this disclosure, however, are not limited to any particular coding standard or format. In general, video encoder 200 and video decoder 300 may be configured to perform the techniques of this disclosure in conjunction with any video coding techniques that use overlapped block motion compensation.(0046] In general, video encoder 200 and video decoder 300 may perform block-based coding of pictures. The term “block” generally refers to a structure including data to be processed e.g., encoded, decoded, or otherwise used in the encoding and / or decoding process). For example, a block may include a two- imensional matrix of samples of luminance and / or chrominance data. In general, video encoder 200 and video decoder 300 may code video data represented in a YUV (e.g., Y, Cb, Cr) format. That is, rather than coding red, green, and blue (RGB) data for samples of a picture, video encoder 200 and video decoder 300 may code luminance and chrominance components, where the chrominance components may include both red hue and blue hue chrominance components. In some examples, video encoder 200 converts recei ved RGB formatted data to a YUV representation prior to encoding, and video decoder 300 converts the YUV representation to the RGB format. Alternatively, pre- and post-processing units (not shown) may perform these conversions.[0047[ This disclosure may generally refer to coding (e.g., encoding and decoding) of pictures to include the process of encoding or decodi ng data of the p icture. Similarly, this disclosure may refer to coding of blocks of a picture to include the process of encoding or decoding data for the blocks, e.g,, prediction and / or residual coding. An encoded video bitstream generally includes a series of values for syntax elements representative of coding decisions (e.g., coding modes) and partitioning of pictures into blocks. Thus, references to coding a picture or a block should generally be understood as coding values for syntax elements forming the picture or block.|0048| HEVC defines various blocks, including coding units (CUs), prediction units (PUs), and transform units (TUs). According to HEVC, a video coder (such as video encoder 200) partitions a coding tree unit (CTU) into CUs according to a quadtree structure. That is, the video coder partitions CTUs and CUs into four equal, nonoverlapping squares, and each node of the quadtree has either zero or four child nodes. Nodes without ch ild nodes may be referred to as “leaf nodes,” and CUs of suc h leaf nodes may include one or more PUs and / or one or more TUs. The video coder may further partition PUs and TUs. For example, in HEVC, a residual quadtree (RQT) represents partitioning of TUs. In HEVC, PUs represent inter-prediction data, while TUs represent residual data. CUs that are intra-predicted include intra-prediction information, such as an intra-mode indication.

[0049] As another example, video encoder 200 and video decoder 300 may be configured to operate according to VVC. According to VVC, a video coder (such as video encoder 200) partitions a picture into a plurality of CTUs. Video encoder 200 may partition a CTU according to a tree structure, such as a quadtree-binary1tree (QTBT) structure or MultiType Tree (MTT) structure. The QTBT structure removes the concepts of multiple partition types, such as the separation between CUs, PUs, and TUs of HEVC. A QTBT structure includes two levels: a first level partitioned according to quadtree partitioning, and a second level partitioned according to binary tree partitioning. A root node of the QTBT structure corresponds to a CTU. Lea f nodes of the binary trees correspond to CUs.[00501 In an MTT partitioning structure, blocks may be partitioned using a quadtree (QT) partition, a binary tree (BT) partition, and one or more types of triple tree (TT) (also called ternary tree (TT)) partitions. A triple or ternary tree partition is a partition where a block is split into three subblocks. In some examples, a triple or ternary tree partition divides a block into three subblocks without dividing the original block through the center. The partitioning types in MTT (e.g., Q, BT, and TT), may be symmetrical or asymmetrical.(0051] When operating according to the AVI codec, video encoder 200 and video decoder 300 may be configured to code video data in blocks. In AV I, the largest coding block that can be processed is called a superblock. In AV I, a superblock can be either 128x128 luma samples or 64x64 luma samples. However, in successor video coding formats (e,g., AV2), a superblock may be defined by different (e.g., larger) luma sample sizes. In some examples, a superblock is the top level of a block quadtree. Video encoder 200 may further partition a superblock into smaller coding blocks. Video encoder 200 may partition a superblock and other coding blocks into smaller blocks using square or non-square partitioning. Non-square blocks may include N / 2xN, NxN / 2, N / 4xN, and NxN / 4 blocks. Video encoder 200 and video decoder 300 may perform separate prediction and transform processes on each of the coding blocks.

[0052] AV I also defines a tile of video data. A tile is a rectangular array of superblocks that may be coded independently of other tiles. That is, video encoder 200 and video decoder 300 may encode and decode, respectively, coding blocks within a tile without using video data from other tiles. However, video encoder 200 and video decoder 300 may perform filtering across tile boundaries. Tiles may be uniform or non-uniform in size. Tile-based coding may enable parallel processing and / or multi-threading for encoder and decoder implementations.

[0053] In some examples, video encoder 200 and video decoder 300 may use a single QTBT or M IT structure to represent each of the luminance and chrominance components, while in other examples, video encoder 200 and video decoder 300 may use two or more QTBT or MTT structures, such as one QTBT / MTT structure for the luminance component and another QTBT / MTT structure for both chrominance components (or two QTBT / MTT structures for respecti ve chrominance components).

[0054] Video encoder 200 and video decoder 300 may be configured to use quadtree partitioning, QTBT partitioning, MTT partitioning, superblock partitioning, or other partitioning structures.(0055 j In some examples, a CTU includes a coding tree block (CTB) of luma samples, two corresponding CTBs of chroma samples of a picture that has three sample arrays, or a CTB of samples of a monochrome picture or a picture that is coded using three separate color planes and syntax structures used to code the samples. A CTB may be an NxN block of samples for some value of N such that the division of a component into CTBs is a partitioning. A component is an array or single sample from one of the three arrays (luma and two chroma) that compose a picture in 4:2:0, 4:2:2, or 4:4:4 color format or the arrayor a single sample of the array that compose a picture in monochrome format. In some examples, a coding block is an MxN block of samples for some values of M and N such that a division of a CTB into coding blocks is a partitioning,

[0056] The blocks (e.g., CTUs or CUs) may be grouped in various ways in a picture. As one example, a brick may refer to a rectangular region of CTU rows within a particular tile in a picture. A tile may be a rectangular region of CTUs within a particular tile column and a particular tile row in a picture. A tile column refers to a rectangular region of CTUs having a height equal to the height of the picture and a width specified by syntax elements (e.g., such as in a picture parameter set), A ti le row refers to a rectangular region of CTUs having a height specified by syntax elements (e.g.. such as in a picture parameter set) and a width equal to the width of the picture.

[0057] In some examples, a tile may be partitioned into multiple bricks., each of which may include one or more CTU rows within the tile. A tile that is not partitioned into multiple bricks may also be referred to as a brick. However, a brick that is a true subset of a tile may not be referred to as a tile. The bricks in a picture may also be arranged in a slice. A slice may be an integer number of bricks of a picture that may be exclusively contained in a single network abstraction layer (NAL) unit. In some examples, a slice includes either a number of complete tiles or only a consecutive sequence of complete bri cks of one ti le.

[0058] This disclosure may use “NxN” and “N by N” interchangeably to refer to the sample dimensions of a block (such as a CU or other video b lock) in terms of vertical and horizontal dimensions, e.g., 16x16 samples or 16 by 16 samples. In general, a 16x16 CU will have 16 samples in a vertical direction (y ~ 16) and 16 samples in a horizontal direction (x 16). Likewise, an NxN CU generally has samples in a vertical direction and N samples in a horizontal direction, where N represents a nonnegative integer value. The samples in a CU may be arranged in row's and columns. Moreover, CUs need not necessar ily have the same number of samples in the horizontal direction as in the vertical direction. For example, CUs may inelude NxM samples, where M is not necessarily equal to N.

[0059] Video encoder 200 encodes video data for CUs representing prediction and / or residual information, and other information. The prediction information indicates how the CU is to be predicted in order to form a prediction block for the CU. The residual information generally represents sample-by-sample differences between samples of the CU prior to encoding and the prediction block.nf 0060 To predict a CU, video encoder 200 may generally form a prediction block for the CU through inter-prediction or intra-prediction, Inter-prediction generally refers to predicting the CU from data of a previously coded picture, whereas intra-prediction generally refers to predicting the CU from previously coded data of the same picture. To perform inter-prediction, video encoder 200 may generate the prediction block using one or more motion vectors. Video encoder 200 may generally perform a motion search to identify a reference block that closely matches the CU, e.g., in terms of differences between the CU and the reference block. Video encoder 200 may calculate a difference metric using a sum of absolute difference (SAD), sum of squared differences (SSD), mean absolute difference (MAD), mean squared differences (MSD), or other such difference calculations to determine whether a reference block closely matches the current CU. In some examples, video encoder 200 may predict the current CU using uni-directional prediction or bi-directional prediction.(0061] Some examples of VVC also provide an affine motion compensation mode, which may be considered an inter-prediction mode. In affine motion compensation mode, video encoder 200 may determine two or more motion vectors that represent non-translational motion, such as zoom in or out, rotation, perspective motion, or other irregular motion types.(0062] To perform intra-prediction, video encoder 200 may select an intra-prediction mode to generate the prediction block. Some examples of VVC provide sixty-seven intra-prediction modes, including various directional modes, as well as planar mode and DC mode. In general, video encoder 200 selects an intra-prediction mode that describes neighboring samples to a current block (e.g., a block of a CU) from which to predict samples of the current block. Such samples may generally be above, above and to the left, or to the left of the current block in the same picture as the current block, assuming video encoder 200 codes CTUs and C s in raster scan order (left to right, top to bottom). (0063] Video encoder 200 encodes data representing the prediction mode for a current block. For example, for inter-prediction modes, video encoder 200 may encode data representing which of the various available inter-prediction modes is used, as well as motion information for the corresponding mode. For uni-directional or bi-directional inter-prediction, fbr example, video encoder 200 may encode motion vectors using advanced motion vector prediction (AMVP) or merge mode. Video encoder 200 may use similar modes to encode motion vectors for affine motion compensation mode.j0064| AVI includes two general techniques for encoding and decoding a coding block of video data. The two general techniques are intra prediction (e,g,, intra frame prediction or spatial prediction) and inter prediction (e.g., inter frame prediction or temporal prediction). In the context of AVI, when predicting blocks of a current frame of video data using an intra prediction mode, video encoder 200 and video decoder 300 do not use video data from other frames of video data. For most intra prediction modes, video encoder 200 encodes blocks of a current frame based on the difference between sample values in the current block and predicted values generated from reference samples in the same frame. Video encoder 200 determines predicted values generated from the reference samples based on the intra prediction mode.|0065| Following prediction, such as intra-prediction or inter-prediction of a block, video encoder 200 may calculate residual data for the block. The residual data, such as a residual block, represents sample by sample differences between the block and a prediction block for the block, formed using the corresponding prediction mode. Video encoder 200 may apply one or more transforms to the residual block, to produce transformed data in a transform domain instead of the sample domain. For example, video encoder 200 may apply a discrete cosine transform (DCT), an integer transform, a wavelet transform, or a conceptually similar transform to residual video data. Additionally, video encoder 200 may apply a secondary transform following the first transform, such as a mode-dependent non-separable secondary transform (MDNSST), a signal dependent transform, a Karhunen-Loeye transform (KLT), or the like. Video encoder 200 produces transform coefficients following application of the one or more transforms.0066| As noted, above, following any transforms to produce transform coefficients, video encoder 200 may perform quantization of the transform coefficients. Quantization generally refers to a process in which transform coefficients are quantized to possibly reduce the amount of data used to represent the transform coefficients, providing further compression. By performing the quantization process, video encoder 200 may reduce the bit depth associated with some or all of the transform coefficients. For example, video encoder 200 may round an n-bit value down to an zn-bit value during quantization, where n is greater than tn. In some examples, to perform quantization, video encoder 200 may perform a bitwise right-shift of the value to be quantized.fo067 Following quantization, video encoder 200 may scan the transform coefficients, producing a one-dimensional vector from the two-dimensional matrix including the quantized transform coefficients. The scan may be designed to place higher energy (andtherefore lower frequency) transform coefficients at the front of the vector and to place lower energy (and therefore higher frequency) transform coefficients at the back of the vector. In some examples, video encoder 200 may utilize a predefined scan order to scan the quantized transform coefficients to produce a serialized vector, and then entropy encode the quantized transform coefficients of the vector. In other examples, video encoder 200 may perform an adaptive scan. After scanning the quantized transform coefficients to form the one-dimensional vector, video encoder 200 may entropy encode the one-dimensional vector, e.g., according to context-adaptive binary arithmetic coding (CABAC). Video encoder 200 may also entropy encode values for syntax elements describing metadata associated with the encoded video data for use by video decoder 300 in decoding the video data.

[0068] Video encoder 200 may further generate syntax data, such as block-based syntax data, picture-based syntax data, and sequence-based syntax data, to video decoder 300, e.g., in a picture header, a block header, a slice header, or other syntax data, such as a sequence parameter set (SPS), picture parameter set (PPS), or video parameter set (VPS). Video decoder 300 may likewise decode such syntax data to determine how to decode corresponding video data.|0069| In this manner, video encoder 200 may generate a bitstream including encoded video data, e.g., syntax elements describing partitioning of a picture into blocks (e.g., CUs) and prediction andfor residual information for the blocks. Ultimately, video decoder 300 may receive the bitstream and decode the encoded video data.

[0070] In general, video decoder 300 performs a reciprocal process to that performed byvideo encoder 200 to decode the encoded video data of the bi t stream. For example, video decoder 300 may decode values for syntax elements of the bitstream using CABAC in a manner substantially similar to, albeit reciprocal to, the CABAC encoding process of video encoder 200. The syntax elements may define partitioning information for partitioning of a picture into CTUs, and partitioning of each CTU according to a corresponding partition structure, such as a QTBT structure, to define CUs of the CTU. The syntax elements may further define prediction and residual information for blocks (e.g,, CUs) of video data.

[0071] The residual information may be represented by, for example, quantized transform coefficients. Video decoder 300 may inverse quantize and inverse transform the quantized transform coefficients of a block to reproduce a residual block for the block. Video decoder 300 uses a signaled prediction mode (intra- or inter-prediction) and relatedprediction information (e,g., motion information for inter-prediction) to form a prediction block for the block. Video decoder 300 may then combine the prediction block and the residual block (on a sample-by-sample basis) to reproduce the original block. Video decoder 300 may perform additional processing, such as performing a debloc ing process to reduce visual artifacts along boundaries of the block.(0072] Any of the video encoding or video decoding processes described above may be performed using a neural network (NN). Additionally or alternatively, a neural network may be trained to efficiently compress video data without necessarily separately performing prediction and residual coding. Studies have shown that embedding neural net works into the hybrid video coding framework of video encoder 200 and video decoder 300 can improve compression efficiency. Neural networks may be used for intra prediction and inter prediction to improve the prediction efficiency. NN-based in-loop filtering and / or post-filtering have also performed well in heuristic testing.(0073] This 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, video encoder 200 may signal values for syntax elements in the bitstream. In general, signaling refers to generating a value in the bitstream. As noted above, source device 102 may transport the bitstream to destination device 116 substantially in real time, or not in real time, such as might occur when storing syntax elements to storage device 112 for later retrieval by destination device 116.(0074] In VVC, conventional block-based coding methodology are utilized. That is, pictures within a video sequence are partitioned into Coding Tree Units (CTUs). Each CTU can be recursively divided into Coding Units (CUs), where each CU is the basic coding processing unit, Intra / Inter prediction, transformation and quantization processes are performed within each CU.(0075] ECM included an inter prediction tool called OBMC. In ECM, OBMC operates on a subblock (4x4) basis, since the minimum unit for storing motion information is currently 4x4, However, OBMC could be applied using subblocks of other sizes. For a subblock, OBMC uses motion infonnation of a neighboring block of the subblock or motion infonnation. of the subblock to adjust the prediction samples that are generated from the current motion information associated with the current subblock.(0076] In one example, it. is assumed that the current subblock is associated with a set of motion information mvA and the prediction sample block generated using the motioninformation set mvA is denoted as predA, A block that is adjacent to the left boundary of the current subblock is associated with another set of motion information mvB. When the set of motion information m and mvB is determined to be different, OBMC generates another prediction sample block predB using the motion information mvB based on the current subblock position. Ute final prediction samples that are adjacent to the left boundary of the current subblock would be a blend of the corresponding prediction samples in predA and predB. In other words, a blended predictor is generated based on predA and predB. A similar process may occur using a block that is adjacent to the top boundary of the c urrent subblock and is associated with another set of motion information mvB.0077] OBMC can operate at subblocks adjacent to the CU boundary (i.e,, boundary subblocks) or inner subblocks (i.e., subblocks inside the current CU) adjacent to a subblock boundary. The inner subblocks are present when the CU is coded using subblock-based prediction method, for example, affine, subblock based temporal motion vector prediction (sbTMVP), decoder-side motion refinement ('DM YR), or bidirectional optical flow (BDOF) based subblock motion derivation. The OBMC can be viewed as a tool to smooth out sample value differences between boundaries.|0078| Local illumination compensation (LIC) is an inter prediction technique to model local illumination variation between a current block and its prediction block as a function of that between a current block tem late and a reference block template. The parameters of the function can be denoted by a scale a and an offset / >’, which forms a linear equation, that is, a*p[x]T i to compensate illumination changes, where p[x] is a reference sample pointed to by MV at a location x. on reference picture. Since a and fl can be derived based on a current block template and a reference block template, no signaling overhead is required for them, except that an LIC flag is signaled for AMVP mode to indicate the use of LIC.|0079 The local illumination compensation proposed in Seregin et al,i4CE4-3.1a and CE4~3.1b: Unidirectional local illumination compensation with affine prediction’5, Joint Video Experts Team (JVET) of ITU-T SG 16 WP 3 and ISO / IEC JTC 1 / SC 29 / WG 11, 15 th Mee ting: Gothenb urg, SE, 3-12 J uly 2019, document J VET-00066, is used for uniprediction inter CUs with the following modifications.♦ Intra neighbor samples can be used in LIC parameter derivation;• LIC is disabled for blocks with less than 32 luma samples;• For both non-subblock and affine modes, LIC parameter derivation is performed based on the template block samples corresponding to the current CU, instead of partial template block samples corresponding to first top-left 16 16 unit;* Samples of the reference block template are generated by using motion compensation with the block motion vector without rounding the block motion vector to integer-pel precision,(0080] In Xiu et al., “EES-TestS.?'. Improvements on local illumination compensation” Joint Video Experts 'learn (JVET) of ITU-T SG 1.6 WP 3 and ISO / IEC JTC 1 / SC 29, 30th Meeting, Antalya, TR, 21-28 April 2023, document JVET-AD0213, LIC mode is extended to bi-predictive CUs and is adopted into ECM, where two different linear models are applied to the two prediction blocks which are then combined to generate the bi-pr ediction samples of the current CU, e.g,,p'[%,y] = (i - m) - po y] + ^ - p]ky]andPoky] = «o ■ Pok ] + p0where a0andand, indicate the scales and the offsets in L0 and Li, respectively; indicates the weight (as indicated by the CU-level BCW index) for the weighted combination of L0 and LI predictions. L0 and 1.1 are lists of motion vector predictors. L0 and LI predictions are predictions based on motion vector predictors In L0 and LI, respectively.(0081] The LIC method of Xiu firstly derives the L0 parameters (i.e., the LIC parameters derived based on an L0 motion vector predictor) by minimizing the difference between an L0 template prediction Toand the template T and the samples in T are updated by subtracting the corresponding samples in To. Then, the LI parameters (i.e., the LIC parameters derived based on an L0 motion vector predictor) are calculated that minimize the difference between LI template prediction 7) and the updated template. Finally, the LO parameter is refined again in the same wave Following the current LIC design, one flagis signalled for AMVP bi-predicted CUs for the indication of the LIC mode while the flag is inherited for merge related inter CUs.

[0082] In Kim ct al., “Non-EE2: OBMC extension with intra prediction, “Joint Video Experts Team (J VET') of ITU-T SG 16 WP 3 and ISO / IEC JTC 1 / SC 29, 35th Meeting, Sapporo, JP, 12—1.9 July 2024, document JVET-AI0154, and Kim et ah, “EE2-3.3: OBMC extension with intra prediction”. Joint Video Experts Team (JVET) of ITU-T SG 16 WP 3 and ISO / IEC JTC 1 / SC 29, 36th Meeting, Kerner, TR, 1-8 November 2024, document JVET-AJ0161, in addition to the existing OBMC process, top and left boundary pixels of the current block are blended using an intra prediction block generated with the intra prediction mode derived by applying decoder-side intra mode derivation (DIMD) on the neighboring reconstructed samples.

[0083] FIG. 2 illustrates an example of the OBMC extension with intra prediction, showing how boundary pixels adjacent to intra blocks are processed. In the example of FIG. 2, a current block 250 includes boundary Subblocks 252A-252G (collectively, “boundary subblocks 252”). Boundary subblocks 252 are adjacent to neighboring blocks 254A-254H (collectively, “neighboring blocks 254”). In the example of FIG. 2, neighboring blocks 254A, 254B, 254D, 254E, 254F, and 254H are inter blocks (i.e., blocks predicted using inter prediction). In the example of FIG. 2, neighboring blocks 254C and 254G are intra blocks (i.e., blocks predicted using intra prediction). As indicated in portion 256 of FIG. 2, a video coder (e.g., video encoder 200 or video decoder 300) may generate initial motion-compensated predictors for boundary subblocks 254A, 252B, 252 D, 252E, and 252G using motion information associated with boundary subblocks 254A, 252B, 252D, 252E, and 252G and generate secondary predictors for boundary' subblocks 254A, 252B, 252D, 252E, and 252G using motion information associated with neighboring blocks 254A, 254B, 254D, 254E, 254F, and 254H. As indicated in portion 258 of FIG. 2, the video coder uses motion infonnation associated with boundary subblocks 252C and 252F to generate an initial motion-compensated predictor and applies DIMD to generate secondary predictors for boundary subblocks 252C and 252F using reconstructed samples of neighboring blocks 254C and 254G. As shown in part 260 of FIG. 2, the initial motion-compensated predictors and the secondary predictors for each of boundary subblocks 252 are blended to generate a blended OBMC-based predictor for current block 250.

[0084] Kidani et al.. “EE2-related: Extended overlapped block blending for MV / BV based prediction”, Joint Video Experts Team (JVET) of ITU-T SG 16 WP 3 and ISO / IECJTC 1 / SC 29, 36th Meeting, Kerner, TR, 1-8 November 2024, document JVET-AJ0078 (hereinafter, “JVET-AJ0078”), proposes an extended overlapped block blending for motion vector (MV) / bIock vector (BV) based prediction. Specifically, JVET-AJ0078 introduces overlapped block blending to intra block copy (IBC) or intra template matching prediction (IntraTMP) applied current blocks regardless of prediction mode in neighboring blocks using MV, B V. or intra prediction mode (IPM).

[0085] In hardware video codecs, inter prediction is typically done before intra prediction as a different pass so that the complex motion compensation process can be done earlier and ready for the reconstruction. In the current ECM, when LIC is applied with OBMC, LIC is performed on top of motion compensated signal using the motion information of current block, then OBMC is performed on top of the output of LIC. However, note that LIC may need to reference the neighboring reconstructed samples to derive the parameters, which may then require OBMC to be performed after neighbouring reconstruction samples are ready. Similarly, when intra prediction is used in OBMC, OBMC may also require inter prediction related processes in OBMC to be performed after neighbouring blocks are reconstructed. Especially when inner subblock OBMC is applied, inner subblock OBMC is performed after the boundary OBMC is finished. Such dependency causes significant delays in hardware decoding.

[0086] This disclosure describes video coding techniques in which LIC with OBMC and intra prediction with OBMC are designed such that the inter prediction OBMC can be done without referencing neighboring reconstructed samples. Inter prediction in OBMC is done before LIC and intra prediction.

[0087] In some examples, a video coder (e.g., video encoder 200 or video decoder 300) first performs motion compensation using the motion information of the current block to generate a Is’ predictor (e.g., an initial motion-compensated predictor), performs inner subblock OBMC (if applicable) to generate a 2i!dpredictor, and then performs boundary OBMC (e.g., using motion information of neighboring blocks to perform motion compensation and perform blending with the 2ndpredictor) to generate output as a 3tdpredictor (e.g., an OBMC- based predictor), and then applies LIC parameters (which are derived with referencing to the neighboring reconstructed samples) on top of the 3rdpredictor to generate a final prediction signal (e.g., an LIC-based predictor) for the current block.

[0088] Thus, video encoder 200 or video decoder 300 may perform motion compensation using motion information of a cunent block to generate a first predictor. Video encoder200 or video decoder 300 may then perform OBMC to generate a second predictor for the current block based on the first predictor Additionally, video encoder 200 or video decoder 300 may derive local illumination compensation (LIC) parameters based on neighboring reconstructed samples. Video encoder 200 or video decoder 300 may then apply the LIC parameters to the second predictor to generate a third predictor for the current block. Video encoder 200 or video decoder 300 may encode or decode the current block based on the third predictor for the current block,|0089| In some examples, video encoder 200 or video decoder 300 performs motion compensation using the motion information of the current block to generate a!*’■ predictor (e.g., an initial motion-compensated predictor), performs inner subblock OBMC (if applicable) to generate a 2ndpredictor, and then boundary' OBMC is performed (i.e. using motion information of neighboring blocks to perform motion compensation and perform blending with the 2ndpredictor) to generate output as a 3,dpredictor (e.g., an OBMC-based predictor), and then performs intra prediction using the intra prediction information of neighboring blocks (e.g., generates an infra-based predictor) and blends with the 3rdpredictor to generate a final prediction signal (e.g... a blended predictor) for the current block. Note that when genera ting the 3rdpredi ctor, if a neighboring block does not have motion information (e.g., the neighboring block is an intra prediction block), two solutions can be used. In one solution, video encoder 200 video decoder 300 skip the corresponding subblock in the process, in another solution,, video encoder 200 and video decoder 300 use available motion information of another neighboring block. The final step that performs intra prediction is also applicable if a corresponding neighboring block is an intra prediction block or contains intra prediction information.

[0090] When LIC and intra prediction are both applicable to OBMC in current block, video encoder 200 and video decoder 300 may apply the following steps:1. Perform motion compensation using the motion information of the cun ent block to generate a Is' predictor (e.g., an initial motion-compensated predictor).2. Perform inner subblock OBMC (if applicable) to generate a 2adpredictor.3. Perform boundary OBMC (i.e. using motion information of neighboring blocks to perform motion compensation and perforin blending with the 2tdpredictor) to generate output as a 3Tdpredictor (e.g., an OBMC-based predictor).4. Apply LIC parameters (which are derived with referencing to the neighboring reconstructed samples) on lop of the 3ldpredictor to generate a 4dlpredictor (e.g., an LIC-based predictor).5, Perfomi intra prediction using the intra prediction information of neighboring blocks (e.g., generate an intra-based predictor) and perform blending with the 3fdpredictor (or, in some examples, the 4thpredictor) to generate final prediction signal (e.g,, a blended predictor) for the current block.|0091 ] FIG. 3 is a block diagram illustrating an example video encoder 200 that may perform the techniques of this disclosure. FIG. 3 is provided for purposes of explanation and should not be considered limiting of the techniques as broadly exemplified, and described in this disclosure. For purposes of explanation, this disclosure describes video encoder 200 according to the techniques ofVVC and HEVC, However, the techniques of this disclosure may be performed by video encoding devices that are configured to other video coding standards and video coding formats, such as AVI and successors to the AV I video coding format.

[0092] In the example of FIG. 3. video encoder 200 includes video data memory 330, mode selection unit 302. residual generation unit 304, transform processing unit 306, quantization unit 308, inverse quantization unit 310, inverse transform processing unit 31, reconstruction unit 314, filter unit 316, decoded picture buffer (DPB) 318, and entropy encoding unit 320.. Any or all of video data memory 330, mode selection unit 302, residual generation unit 304, transform processing unit 306, quantization unit 308, inverse quantization unit 310, inverse transform processing unit 312, reconstruction unit 314, filter unit 316, DPB 318, and entropy encoding unit 320 may be implemented in one or more processors or in processing circuitry'. For instance, the units of video encoder 200 may be implemented as one or more circuits or logic elements as part of hardware circuitry, or as part of a processor, ASIC, or FPGA. Moreover, video encoder 200 may include additional or alternative processors or processing circuitry' to perform these and other functions.|0093] Video data memory 330 is an example of a memory system that may store video data to be encoded by the components of video encoder 200. Video encoder 200 may receive the video data stored in video data memory 330 from, for example, video source 104 (FIG. 1). DPB 318 is an example of a memory system that may act as a reference picture memory that stores reference video data for use in prediction of subsequent video data by video encoder 200. Video data memory 330 and DPB 318 may each be formed by any of a variety of one or more memory devices or memory units, such as dynamic random access memory (DRAM), including synchronous DRAM (SDRAM),magnetoresistive RAM (MRAM), resistive RAM (RRAM), or other types of memory devices. Video data memory 330 and DPB 318 may be provided by the same memory device or separate memory' devices. In various examples, video data memory 330 may be on-chip with other components of video encoder 200, as illustrated, or off-chip relative to those components.(0094 In this disclosure, reference to video data memory 330 should not be interpreted as being limited to memory internal to video encoder 200, unless specifically described as such, or memory external to video encoder 200, unless specifically described as such. Rather, reference to video data memory 330 should be understood as reference memory that stores video data that video encoder 200 receives for encoding (e.g., video data for a current block that is to be encoded). Memory' 106 of FIG. I may also provide temporary storage of outputs from the various units of video encoder 200.

[9095] The various units of FIG. 3 are illustrated to assist with understanding the operations performed by video encoder 200. The units may be implemented as fixed-function circuits, programmable circuits, or a combination thereof Fixed-function circuits refer to circuits that provide particular functionality, and are preset on the operations that can be performed. Programmable circuits refer to circuits that can be programmed to perform various tasks, and provide flexible fonctionality in the operations that can be performed. For instance, programmable circuits may execute software or firmware that cause the programmable circuits to operate in the manner defined by instructions of the software or firmware. Fixed-function circuits may execute software instructions (e.g., to recei ve parameters or output parameters), but the types of operations that the fixed-function circuits perform are generally immutable. In some examples, one or more of the units may be distinct circuit blocks (fixed-function or programmable), and in some examples, one or more of the units may be integrated circuits.(0096] Video encoder 200 may include arithmetic logic units (ALUs), elementary function units (EFUs), digital circuits, analog circuits, and / or programmable cores, formed from programmable circuits. In examples where the operations of video encoder 200 are performed using software executed by the programmable circuits, memory 106 (FIG. 1) may Store the instructions (e.g., object code) of the software that video encoder 200 receives and executes, or another memory within video encoder 200 (not shown) may store such instructions.

[0097] Video data memory 330 is configured to store recei ved video data. Video encoder 200 may retrieve a picture of the video data from video data memory 330 and provide thevideo data to residual generation unit 304 and mode selection unit 302. Video data in video data memory 330 may be raw video data that is to be encoded.

[0098] Mode selection unit 302 includes a motion estimation unit 322, a motion compensation unit 324, and an intra-prediction unit 326. Mode selection unit 302 may include additional functional units to perform video prediction in accordance with other prediction inodes. As examples, mode selection unit 302 may include a palette unit, an intra-block copy unit (which may be part of motion estimation unit 322 and / or motion compensation unit 324), an affine unit, a linear model (I.. M) unit, or the like.

[0099] Mode selection unit 302 generally coordinates multiple encoding passes to test combinations of encoding parameters and resulting rate-distortion values for such combinations. The encoding parameters may include partitioning of CTUs into CUs, prediction modes for the CUs. transform types for residual data of the CUs, quantization parameters fbr residual data of the CUs, and so on. Mode selection unit 302 may ultimately select the combination of encoding parameters having rate-distortion values that are better than the other tested combinations.

[0100] Video encoder 200 may partition a picture retrieved from video data memory’ 330 into a series of CTUs, and encapsulate one or more CTUs within a slice. Mode selection unit 302 may partition a CTU of the picture in accordance with a tree structure, such as the MTT structure, QTBT structure, superblock structure, or the quad-tree structure described above. As described above, video encoder 200 may form one or more CUs from partitioning a CTU according to the tree structure. Such a CU may also be referred to generally as a ''video block’’ or “block.”

[0101] In general, mode selection unit 302 also controls the components thereof (e.g., motion estimation unit 322, motion compensation unit 324, and intra-prediction unit 326) to generate a prediction block for a current block (e.g., a current CU, or in HEVC, the overlapping portion of a PU and a TU). For inter-prediction of a cun-ent block, motion estimation unit 22 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 DPB 318). In particular, motion estimation unit 322 may calculate a value representative of how similar a potential reference block is to the current block, e.g., according to sum of absolute difference (SAD), sum of squared differences (SSD), mean absolute difference (MAD), mean squared differences (MSD), or the like. Motion estimation unit 322 may generally perform these calculations using sample-by-sample differences between the current block and the reference block being considered. Motionestimation unit 322 may identify a reference block having a lowest value resulting from these calculations, indicating a reference block that most closely matches the current block.

[0102] Motion estimation unit 322 may form one or more motion vectors (MVs) that defines the positions of the reference blocks in the reference pictures relative to the position of the current block in a current picture. Motion estimation unit 322 may then provide the motion vectors to motion compensation unit 324. For example, for unidirectional inter-prediction, motion estimation unit 322 may provide a Single motion vector, whereas for bi-directional inter-prediction, motion estimation unit 322 may provide two motion vectors. Motion compensation unit 324 may then generate a prediction block using the motion vectors. For example, motion compensation unit 324 may retrieve data of the reference block using the motion vector. As another example, if the motion vector has fractional sample precision, motion compensation unit 324 may interpolate values for the prediction block according to one or more interpolation filters. Moreover, tor bi-directional inter-prediction, motion compensation unit 324 may retrieve data for two reference blocks identified by respective motion vectors and combine the retrieved data, e.g., through sample-by~sample averaging or weighted a veraging. In some examples, motion compensation unit 324 may perform OBMC before applying L1C and / or before generating an intra-based predictor to be blended with an OBMC-based predictor.

[0103] When operating according to the AV 1 video coding format; motion estimation unit 322 and motion compensation unit 324 may be configured to encode coding blocks of video data (e.g., both luma and chroma coding blocks) using translational motion compensation, affine motion compensation, overlapped block motion compensation (OBMC), and / or compound inter-intra prediction.

[0104] As another example, for intra-prediction, or intra-prediction coding, intraprediction unit 326 may generate the prediction block from samples neighboring the current block. For example, for directional modes, intra-prediction unit 326 may generally mathematically combine values of neighboring samples and populate these calculated values in the defined direction across the current block to produce the prediction block. As another example, for DC mode, infra-prediction unit 326 may calculate an average of the neighboring samples to the current block and generate the prediction block to include this resulting average for each sample of the prediction block.

[0105] When operating according to the AVI video coding format, intra-prediction unit 326 may be configured to encode coding blocks of video data (e.g... both luma and chroma coding blocks) using directional intra prediction, non-directional intra prediction, recursive filter intra prediction, chroma-ffom-luma (CFL) prediction, intra block copy (IBC), and / or color palette mode. Mode selection unit 302 may include additional functional units to perform video prediction in accordance with other prediction modes,

[0106] Mode selection unit 302 provides the prediction block to residual generation unit.304. Residual generat ion unit 304 recei ves a raw, unencoded version of the current block from video data memory 330 and the prediction block from mode selection unit 302, Residual generation unit 304 calculates sample-by-sample differences between the current block and the prediction block. The resulting sample-by-sample differences define a residual block for the current block. In some examples, residual generation unit 304 may also determine differences between sample values in the residual block to generate a residual block using residual differential pulse code modulation (RDFCM). In some examples, residual generation unit 304 may be formed using one or more subtractor circuits that perform binary subtraction,

[0107] In examples where mode selection unit 302 partitions CUs into PUs, each PU may be associated with a luma prediction unit and corresponding chroma prediction units. Video encoder 200 and video decoder 300 may support PUs having various sizes. As indicated above, the size of a CU may refer to the size of the luma coding block of the CU and the size of a PU may refer to the size of a luma prediction unit of the PU, Assuming that, the size of a particular CU is 2 x2N, 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. Video encoder 200 and video decoder 300 may also support asymmetric partitioning for PU sizes of 2NxnU, 2NxnD, nLx2N, and nR.x.2N for inter prediction.[0108| In examples where mode selection unit 302 does not further partition a CU into PUs, each CU may be associated with a luma coding block and corresponding chroma coding blocks. As above, the size of a CU may refer to the size of the luma coding block of the CU, The video encoder 200 and video decoder 300 may support CU sizes of 2Nx2N, 2NxN, or Nx2N.

[0109] For other video coding techniques such as an intra-block copy mode coding, an affine-mode coding, and linear model (LM) mode coding, as some examples, mode selection unit 302, via respective units associated with the coding techniques, generates aprediction block for the current block being encoded. In some examples, such as palette mode coding, mode selection unit 302 may not generate a prediction block, and instead generate syntax elements that indicate the manner in which to reconstruct the block based on a selected palete. In such inodes, mode selection unit 302 may provide these syntax elements to entropy encoding unit 320 to be encoded,(0110] As described above, residual generation unit 304 receives the video data for the current block and the corresponding prediction block. Residual generation unit 304 then generates a residual block for the current block. To generate the residual block, residual generation unit 304 calculates sampie-by-sarnple differences between the prediction block and the current block.[01111 Transform processing unit 306 applies one or more transforms to the residual block to generate a block of transform coefficients (referred to herein as a “transform coefficient block”). Transform processing unit 306 may apply various transforms to a residual block to form the transform coefficient block. For example, transform processing unit 306 may apply a discrete cosine transform (DCT), a directional transform, a Karhunen-Loeve transform (KLT), or a conceptually similar transform to a residual block. In some examples, transform processing unit 306 may perform multiple transforms to a residual block, e.g., a primary transform and a secondary' transform, such as a rotational transform. In some examples, transform processing unit 306 does not apply transforms to a residual block.

[0112] When operating according to AVI, transform processing unit 306 may apply one or more transforms to the residual block to generate a block of transform coefficients (referred to herein as a “transform coefficient block”). Transform processing unit 306 may apply various transforms to a residual block to form the transform coefficient block. For example, transform processing unit 306 may apply a horizontal / vertical transform combination that may include a discrete cosine transform (DCT), an asymmetric discrete sine transform (ADST), a flipped ADST (e.g., an ADST in reverse order), and an identity transform (IDTX). When using an identity transform, the transform is skipped in one of the vertical or horizontal directions. In some examples, transform processing may be skipped.(0113] Quantization unit 308 may quantize the transform coefficients in a transform coefficient block, to produce a quantized transform coefficient block. Quantization unit 308 may quantize transform coefficients of a transform coefficient block according to a quantization parameter (QP) value associated with the current block; Video encoder 200(e.g., via mode selection unit 302) may adjust the degree of quantization applied to the transform coefficient blocks associated with the current block by adjusting the QI? value associated with the CU. Quantization may introduce loss of information, and thus, quantized transform coefficients may have lower precision than the original transform coefficients produced by transform processing unit 306.(01.1.4] Inverse quantization unit 310 and inverse transform processing unit 312 may apply inverse quantization and inverse transforms to a quantized transform coefficient block, respectively, to reconstruct a residual block from the transform coefficient block. Reconstruction unit 314 may produce a reconstructed block corresponding to the cunent block (albeit potentially with some degree of distortion) based on the reconstructed residual block and a prediction block generated by mode selection unit 302. For example, reconstruction unit 314 may add samples of the reconstructed residual block to corresponding samples from the prediction block generated by mode selection unit 302 to produce the reconstructed block,

[0115] Filter unit 316 may perform one or more filter operations on reconstructed blocks. For example, filter unit 316 may perform deblocking operations to reduce blockiness artifacts along edges of CUs. Operations of filter unit 316 may be skipped, in some examples.

[0116] When operating according io AVI, filter unit 316 may perform one or more filter operations on reconstructed blocks. For example, filter unit 316 may perform deblocking operations to reduce blockiness artifacts along edges of CUs. In other examples, filter unit 316 may apply a constrained directional enhancement filter (CDEF), which may be applied after deblocking, and may include the application of non-separable, non-linear, low-pass directional filters based on estimated edge directions. Filter unit 316 may also include a loop restoration filter, which is applied after CDEF, and may include a separable symmetric normalized Wiener filter or a dual self-guided filter.(0117| Video encoder 200 stores reconstructed blocks in DFB 318. For instance, in examples where operations of filter unit 316 are not performed, reconstruction unit 314 may store reconstructed blocks to DPB 318. In examples where operations of filter unit 16 are performed, filter unit 316 may store the filtered reconstructed blocks to DPB 318. Motion estimation unit 322 and motion, compensation unit 324 may retrieve a reference picture ftom DPB 318, formed from the reconstructed (and potentially filtered) blocks, to inter-predict blocks of subsequently encoded pictures. In addition, intra-prediction unit326 may use reconstructed blocks in DPB 18 of a current picture to intra-predict other blocks in the current picture.

[0118] In general, entropy encoding unit 320 may entropy encode syntax elements received from other functional components of video encoder 200, For example, entropy encoding unit 320 may entropy encode quantized transform coefficient blocks from quantization unit 308. As another example, entropy encoding unit 320 may entropy encode prediction syntax elements (e.g., motion information for inter-prediction or intramode information for intra-prediction) from mode selection unit 302. Entropy encoding unit 320 may perform one or more entropy encoding operations on the syntax elements, which are another example of video data, to generate entropy-encoded data. For example, entropy encoding unit 320 may 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 (SB AC) operation, a Probability Interval Partitioning Entropy (PIPE) coding operation, an Exponential-Golomb encoding operation, or another type of entropy encoding operation on the data. In some examples, entropy encoding unit 320 may operate in bypass mode where syntax elements are not entropy encoded.(0119] Video encoder 200 may output a bitstream that includes the entropy encoded Syntax elements needed to reconstruct blocks of a slice or picture. In particular, entropy encoding unit 320 max' output the bitstream,

[0120] In accordance with AVI, entropy encoding unit 320 may be configured as a symbol-to-symbol adaptive multi-symbol arithmetic coder. A syntax element in AVI includes an alphabet of N elements, and a context (e.g., probability model) includes a set of probabilities. Entropy encoding unit 320 may store the probabilities as mbit (e.g., 15-bit) cumulative distribution functions (CDFs). Entropy encoding unit 320 may perform recursive scaling, with an update factor based on the alphabet size, to update the contexts.(0121] The operations described above are described with respect to a block. Such description should be understood as being operations for a luma coding block and / or chroma coding blocks. As described above, in some examples, the luma coding block and chroma coding blocks are luma and chroma components of a CU. In some examples, the luma coding block and the chroma coding blocks are luma and chroma components of a PU.0122] In some examples, operations performed with respect to a luma coding block need not be repeated for the chroma coding blocks. As one example, operations to identify a motion vector (MV) and reference picture for a luma coding block need not be repeated for identifying a M V and reference picture for the chroma blocks. Rather, the MV for the luma coding block may be scaled to detennine the MV for the chroma blocks, and the reference picture may be the same. As another example, the intra-pre iction process may be the same for the luma coding block and the chroma coding blocks.

[0123] Video encoder 200 represents an example of a device con fi gured to encode video data including a memory configured to store video data, and one or more processing units implemented in circuitry and configured to perform motion compensation using motion information of a current block to generate a first predictor; perform overlapped block motion compensation (OBMC) to generate a second pre ictor based on the first predictor; deriving local illumination compensation (LIC) parameters based on neighboring reconstructed samples; after performing OBMC, apply the LIC parameters to the second predictor to generate a third predictor for the current block; and encode the current block based on the third predictor.|0124| In some examples, video encoder 200 represents an example of a device configured to encode video data including a memory configured to store video data, and one or more processing units implemented in circuitry and configured to perform motion compensation using motion information of a current block to generate a first predictor; perform inner subblock overlapped-block motion compensation (OBMC) to generate a second predictor for the current block based on the first predictor; use motion Information of one or more neighboring blocks to perform motion compensation and perform blending with the second predictor to generate a third predictor for the current block; apply local illumination compensation (LIC) parameters to the third predictor to generate a fourth predictor for the current block; and encode the current block based on the fourth predictor for the current block.|0125j In some examples, video encoder 200 represents an example of a video encoding device including a memory configured to store video data, and one or more processing uni ts implemented in circuitry and configured to perform motion compensation using motion information of a current block to genera te a first predic tor; perform inner subblock OBMC to generate a second predictor for the current block based on the first predictor; use motion information of one or more neighboring blocks to perform motion compensation and perform blending with the second predictor to generate a thirdpredictor for the current block; perform intra prediction using intra prediction information of one or more neighboring blocks and blending with the third predictor to generate a fourth predictor for the current block; and encode the current block based on the fourth predictor for the current block,10126 J In some examples, video encoder 200 represents an example of a video encoding device including a memory configured to store video data, and one or more processing units implemented in circuitry and configured to perform motion compensation using motion information of a current block to generate a first predictor; perform inner subblock OBMC to generate a second predictor for the current block based on the first predictor; use motion information of one or more neighboring blocks to perform motion compensation and blending with the second predictor to generate a third predictor for the current block; apply LIC parameters to the third predictor to generate a fourth predictor for the current block; perform intra prediction using intra prediction information of one or more neighboring blocks and blending with the fourth predictor to generate a fifth predictor; and encode the current block based on the fifth predictor for the current block.

[0127] FIG. 4 is a block diagram illustrating an example video decoder 300 that may perform the techniques of this disclosure. FIG. 4 is provided for purposes of explanation and is not limiting on the techniques as broadly exemplified and described in this disclosure. For purposes of explanation, this disclosure describes video decoder 300 according to the techniques of VVC and HE VC. However, the techniques of this disclosure may be performed by video coding devices that are configured to other video coding standards.

[0128] In the example of FIG. 4, video decoder 300 includes coded pic ture buffer (CPB) memory 420, entropy decoding unit 402, prediction processing unit 404, Inverse quantization unit 400, inverse transform processing unit 408, reconstruction unit 410, filter unit 412, and DPB 414. Any or all of CPB memory 420, entropy decoding unit 402, prediction processing unit 404, inverse quantization unit 406, inverse transform processing unit 408, reconstruction unit 41.0, filter unit 412, and DPB 414 may be implemented in one or more processors or in processing circuitry. For instance, the units of video decoder 300 may be implemented as one or more circuits or logic elements as part of hardware circuitry, or as part of a processor, ASIC, or FPGA. Moreover, video decoder 300 may include additional or alternative processors or processing circuitry to perform these and other functions,(0129] Prediction processing unit 404 includes motion compensation unit 416 and intraprediction unit 418. Prediction processing unit 404 may include additional units to perform prediction in accordance with other prediction modes. As examples, prediction processing unit 404 may include a palette unit, an intra-block copy unit (which may form part of motion compensation unit 416), an affine unit, a linear model (LM) unit, or the like. In accordance with one or more techniques of this disclosure, prediction processing unit 404 may perform OBMC before applying LIC and / or before generating an intrabased predictor to be blended with an OBMC-based predictor. In other examples, video decoder 300 may include more, fewer, or different functional components.(0130] When operating according to AVI, motion compensation unit 416 may be configured to decode coding blocks of video data (e.g., both luma and chroma coding blocks) using translational motion compensation, affine motion compensation, OBMC, andor compound inter-intra prediction, as described above. Intra-prediction unit 418 may be configured to decode coding blocks of video data (e.g., both luma and chroma coding blocks) using directional intra prediction, non-directional intra prediction, recursive filter intra prediction, CFL, IBC, and / or color palette mode, as described above.(0131] CPB memory 420 is an example of a memory system that may store video data, such as an encoded video bitstream, to be decoded by the components of video decoder 300. The video data stored in CPB memory 420 may be obtained, for example, from computer-readable medium 110 (FIG. 1). CPB memory 420 may include a CPB that stores encoded video data (e.g., syntax elements) from an encoded video bitstream. Also, CPB memory 420 may store video data other than syntax elements of a coded picture, such as temporary data representing outputs from the various units of video decoder 300. DPB 414 is au example of a memory system that generally stores decoded pictures, which video decoder 300 may output and / or use as reference video data when decoding subsequent data or pictures of the encoded video bitstream, CPB memory 420 and DPB 414 may each be formed by any of a variety o f memory devices or memory units, such as DRAM, including SDRAM, MR AM, RR. AM, or other types of memory devices. CPB memory 420 and DPB 414 may be provided by the same memory device or separate memory devices. In various examples, CPB memory 420 may be on-chip with other components of video decoder 300, or off-chip relati e to those components.(0132] Additionally or alternatively, in some examples, video decoder 300 may retrieve coded video data from memory 120 (FIG. I). That is, memory 120 may store data as discussed above with CPB memory 420. Likewise, memory 120 may store instructionsto be executed, by video decoder 300, when some or all of the functionality of video decoder 300 is implemented in software to be executed by processing circuitry of video decoder 300,

[0133] The various units shown in FIG. 4 are illustrated to assist with understanding the operations performed by video decoder 300. The units may be implemented as fixed-function circuits, programmable circuits, or a combination thereof. Similar to FIG. 3, fixed-function circuits refer to circuits that provide particular functionality, and are preset on 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 instance, programmable circuits may execute software or firmware that cause the programmable circuits to operate in the manner defined by instructions of the software or firmware. Fixed- function circuits may execute software instructions (e.g., to receive parameters or output parameters), but the types of operations that the fixed-function circuits perform are generally immutable. In some examples, one or more of the units may be distinct, circuit blocks (fixed-function or programmable), and in some examples, one or more of the units may be integrated circuits.

[0134] Video decoder 300 may include ALUs, EFUs, digital circuits, analog circuits, and / or programmable cores formed from programmable circuits. In examples where the operations of video decoder 300 are performed by software executing o« the programmable circuits, on-chip or off-chip memory may store instructions (e.g., object code) of the software that video decoder 300 receives and executes.

[0135] Entropy decoding unit 402 may receive encoded video data from the CPB and entropy decode the video data to reproduce syntax elements. Prediction processing unit 404, inverse quantization unit 406, inverse transform processing unit 408, reconstraction unit 410, and filter unit 412 may generate decoded video data based on the syntax elements extracted from the bitstream.

[0136] In general, video decoder 300 reconstructs a picture on a block-by-block basis. Video decoder 300 may perform a reconstruction operation on each block individually (where the block currently being reconstructed, i.e., decoded, may be referred to as a “current block”).

[0137] Entropy decoding unit 402 may entropy decode syntax elements defining quantized transform coefficients of a quantized transform coefficient block, as well as transform information, such as a quantization parameter (QP) and / or transform modeindication(s). Inverse quantization unit 406 may use the QP associated with the quantized transform coefficient block to determine a degree of quantization and, likewise, a degree of inverse quantization for inverse quantization unit 406 to apply. Inverse quantization unit 406 may, for example, perform a bitwise left-shift operation to inverse quantize the quantized transform coefficients. Inverse quantization unit 406 may thereby form a transform coefficient block including transform coefficients.

[0138] After inverse quantization unit 406 forms the transform coefficient block, inverse transform processing unit 408 may apply one or more inverse transforms to the transform coefficient block to generate a residual block associated with the current block. For example, inverse transform processing unit 408 may apply an inverse DCT, an inverse integer transform, an inverse Karhunen-Loeve transform (KLT), an inverse rotational transform, an inverse directional transform, or another inverse transform to the transform coefficient block.(0139] Furthermore, prediction processing unit 404 generates a prediction block according to prediction information syntax elements that were entropy decoded by entropy decoding unit 402. For example, if the prediction information syntax elements indicate that the current block is inter-predicted, motion compensation unit 416 may generate the prediction block. In this case, the prediction information syntax elements may indicate a reference picture in DPB 14 from which to retrieve a reference block, as well as a motion vector identifying a location of the reference block in the reference picture relative to the location of the current block in the cunent picture. Motion compensation unit. 416 may generally perform the inter-prediction process in a manner that is substantially similar to that described with respect to motion compensation unit 324 (FIG. 2).

[0140] As another example, if the prediction information syntax elements indicate that the c nent block is mtra-predicted. intra-prediction unit 418 may generate the prediction block according to an intra-prediction mode indicated by the prediction information syntax elements. Again, mtra-prediciion unit 418 may generally perform the intraprediction process in a manner that is substantially similar to that described. with respect to mtra-prediction unit 326 (FIG. 2). Intra-prediction unit 418 may retrieve data of neighboring samples to the current block from DPB 414.(0141] Reconstruction unit 410 may reconstruct the current block using the prediction block and the residual block. For example, reconstruction unit 410 may add samples ofthe residual block to corresponding samples of the prediction block to reconstruct the current block.

[0142] Filter unit 412 may perform one or more filter operations on reconstructed blocks. For example, filter unit 412 may perform deblocking operations to reduce blockiness artifacts along edges of the reconstructed blocks. Operations of filter unit 412 are not necessarily performed in all examples.

[0143] Video decoder 300 may store the reconstructed blocks in DPB 414. For instance, in examples where operations of filter unit 412 are not performed, reconstruction unit 410 may store reconstructed blocks to DPB 414. In examples where operations of filter unit 412 are performed, filter unit 12 may store the filtered reconstructed blocks to DPB 414. As discussed above, DPB 414 may provide reference information, such as samples of a current picture for intra-prediction and previously decoded pictures for subsequent motion compensation, to prediction processing unit 404. Moreover, video decoder 300 may output decoded pictures (e.g., decoded video) from DPB 414 for subsequent presentation on a display device, such as display device 118 of FIG. 1.

[0144] In this manner, video decoder 300 represents an example of a video decoding device including a memory configured to store video data, and one or more processing units implemented in circuitry and configured to perform motion compensation using motion infonnaiion of a current block to generate a first predictor; perform overlapped block motion compensation (OBMC) to generate a second predictor based on the first predictor; deriving local illumination compensation (LIC) parameters based on neighboring reconstructed samples; after performing OBMC, apply the LIC parameters to the second predictor to generate a third predictor for the current block; and encode the current block based on the third predictor.

[0145] In some examples, video decoder 300 represents an example of a video decoding device including a memory configured to store video data, and one or more processing units implemented in circuitry and configured to perform motion compensation using motion information of a current block to generate a first predi ctor; perform inner subblock overlapped-block motion compensation (OBMC) to generate a second predictor for the current block based on the first predictor; use motion information of one or more neighboring blocks to perform motion compensation and perform blending with the second predictor to generate a third predictor for the current block; apply local illumination compensation (LIC) parameters to the third predictor to generate a fourthpredictor for the current block; and decode the current block based on the fourth predictor for the current block.

[0146] In some examples, video decoder 300 represents an example of a video decoding device including a memory configured to store video data, and one or more processing units implemented in circuitry and configured to perform motion compensation using motion information of acurrent block to generate a first predictor; perform inner subblock overlapped-block motion compensation (OBMC) to generate a second predictor for the current block based on the first predictor; use motion information of one or more neighboring blocks to perform motion compensation and perform blending with the second predictor to generate a third predictor for the current block; perform intra prediction using intra prediction information of one or more neighboring blocks and blending with the third predictor to generate a fourth predictor for the current block; and decode the current block based on the fourth predictor for the current block.

[0147] In some examples, video decoder 300 represents an example of a video decoding device including a memory configured to store video data, and one or more processing units implemented in circuitry and configured to perform motion compensation using motion information of a current block to generate a first predictor; perform inner subblock overlapped-block motion compensation (OBMC) to generate a second predictor for the current block based on the first predictor; use motion information of one or more neighboring blocks to perform motion compensation and blending with the second predictor to generate a third predictor for the current block; apply local illumination compensation (LIC) parameters to foe third predictor to generate a fourth predictor for the current block; perform intra prediction using intra prediction information of one or more neighboring blocks and blending with the fourth predictor to generate a fifth predictor; and decode tire current block based on the fifth predictor for the current block;

[0148] FIG. 5 is a flowchart illustrating an example method for encoding a current block in accordance with the techniques of this disclosure. The current block may be or include a current CU. Although described with respect to video encoder 200 (FIGS. 1 and 3), it should be understood that other devices may be configured to perform a method similar to tha t of FIG. 5.

[0149] In this example, video encoder 200 initially predicts the current block (500). For example, video encoder 200 may form a prediction block for the current block. Video encoder 200 may then calculate a residual block for foe current block (502). To calculate the residual block, video encoder 200 may calculate a difference between the original,unencoded block and the prediction block for the current block. Video encoder 200 may then transform the residual block and quantize transform coefficients of the residual block (504). Next, video encoder 200 may scan the quantized transform coefficients of the residual block (506), During the scan, or following the scan, video encoder 200 may entropy encode the transform coefficients (508), For example, video encoder 200 may encode the trans form coefficients using CAVLC or CAB AC. Vi eo encoder 200 may then output the entropy encoded data of the block (510).

[0150] FIG. 6 is a flowchart illustrating an example method for decoding a current block of video data in accordance with the techniques of this disclosure. The current block may be or include a current CU, Although described with respect to video decoder 300 (FIGS, I and 4), it should be understood that other devices may be configured to perform a method similar to that of FIG. 6.

[0151] Video decoder 300 may receive entropy encoded data for the current block, such as entropy encoded prediction information and entropy encoded data for transform coefficients of a residual block corresponding to the cunent block (600). Video decoder 300 may entropy decode the entropy encoded data to determine prediction information for the curren t block and to reproduce transform coefficients of the residual block (602). Video decoder 300 may predict the current block (604), e.g., using an intra- or interprediction mode as indicated by the prediction information for the current block, to calculate a prediction block for the current block. Video decoder 300 may then inverse scan the reproduced transform coefficients (606), to create a block of quantized transform coefficients. Video decoder 300 may then inverse quantize the transform coefficients and apply an inverse transform to the transform coefficients to produce a residual block (608), Video decoder 300 may ultimately decode the cunent block by combining the prediction block and the residual block (610).

[0152] FIG. 7 is a flowchart illustrating an example operation for OBMC with LIC, in accordance with one or more techniques of this disclosure. In the example of FIG. 7, a video coder (e.g., video encoder 200 or video decoder 300) performs motion compensation using motion information of a current block to generate an initial motion-compensated predictor (700). In other words, the video coder may perform motion compensation using the motion information (e.g., one or more motion vectors) of the current block to generate the initial motion-compensated predictor for the current block. The motion compensation may be unidirectional or bidirectional[01531 Additionally, the video coder performs OBMC to generate an OBMC-based predictor fbr the current block (702). For example, for each left boundary subblock of the current block, if a neighboring block that is adjacent to a left boundary of the left boundary subblock is inter predicted and the motion information of the neighboring block is different from the motion information of the left boundary subblock, the video coder genera tes a prediction sample block using the motion information of the neighboring block based on the position of the left boundary subblock. For instance, the video coder may identify a reference loca tion in a reference picture by using a motion vector of the neighboring block starting from the left boundary subblock. The video coder may then use the reference location to determine the prediction sample block. Similarly, for each top boundary subblock of the current block, if a neighboring block that is adjacent to a top boundary of the top boundary' subblock is inter predicted and the motion information of the neighboring block is different from the motion information of the top boundary subblock, the video coder generates a prediction sample block using the motion information of the neighboring block based on the position of the top boundary subblock. The video coder generates the OBMC-based predictor based on the initial motion-compensated predictor and the generated prediction sample blocks of the left and top boundary subblocks. In the OBMC-based predictor, samples that are adjacent to a left boundary of a left boundary subblock a re a blend of the corresponding predicti on samples in the initial motion-compensated predictor and the generated prediction sample block for the left boundary subblock and samples that are adjacent to a top boundary of a top boundary subblock are a blend of the corresponding prediction samples in the initial motion-compensated predictor and the generated prediction sample block for the top boundary subblock. In some examples, the video coder performs inner subblock OBMC as part of generating the OBMC-based predictor.

[0154] After the video coder performs OBMC to generate the OBMC-based predictor, the video coder determines TIC parameters with reference to neighboring reconstructed samples (704). The video coder may then apply the LIC parameters to the OBMC-based predictor for the current block to generate an LIC-based predictor for the current block (706). The video coder may determine and apply the LIC parameters in the manner described above.

[0155] The video coder may then encode or decode the current block based on the LIC-based predictor (708). For example, as part of encoding the current block, the video coder may generate residual data based on the LIC-based predictor and original samples of thecarrent block. The video coder may apply a transform to the residual data to generate transform data, which may then be quantized and entropy encoded. As part of decoding the current block, the video coder may add the third predictor to residual data to generate reconstructed video data for the current block,|0156J FIG. 8 is a flowchart illustrating an example operation for OBMC with intra prediction, in accordance with one or more techniques of this disclosure. In the example of FIG, 8, a video coder (e.g,, video encoder 200 or video decoder 300) performs motion compensation using motion information of a current block to generate an ini tial motion-compensated predictor (800). In other words, the video coder may perform motion compensation using the motion infomiation (e.g,fone or more motion vectors) of the current block to generate the initial motion-compensated predictor for the current block. The motion compensation may be unidirectional or bidirectional.|0157| Additionally, the video coder performs OBMC to generate an OBMC-based predictor for the current block (802). For example, for each left boundary subblock of the current block, if a neighboring block that is adjacent to a left boundary of the left boundary subblock is inter predicted and the motion information of the neighboring block is different from the motion information of the left boundary subblock, the video coder generates a prediction sample block using the motion information of the neighboring block based on the position of the left boundary subblock. Similarly, for each top boundary subblock of the current block, if a neighboring block that is adjacent to a top boundary of the top boundary subblock is inter predicted and the motion infomiation of the neighboring block is different from the motion information of the top boundary subblock, the video coder generates a prediction sample block using the motion i nformation of the neighboring block based on the position of the top boundary subblock. The video coder generates the OBMC-based predictor based on the initial motion-compensated predictor and the generated prediction sample blocks of the left and top boundary subblocks. In the OBMC-based predictor, samples that are adjacent to a left boundary of a left boundary subblock are a blend of the corresponding predicti on samples in the initial motion-compensated predictor and the generated prediction sample block for the left boundary subblock and samples that are adjacent to a top boundary of a top boundary subblock are a blend of the corresponding prediction samples in the Initial motion-compensated predictor and the generated prediction sample block for the top boundary subblock. In some examples., the video coder performs inner subblock OBMC as part of generating the second predictor.(0158] In some examples, when generat ing the OBMC-based predictor, if a neighboring block of a current subblock does not have motion infor mation (i. e., the neighboring block is an intra prediction block), two solutions can be used. In one solution, the current subblock is skipped in the process. For instance, the OBMC-based predictor includes the same data for the current subblock as the first predictor. In another solution, the available motion information of another neighboring block is used to generate prediction samples for the current subblock. The other neighboring block is not directly adjacent to the current subblock,(0159] After the video coder performs OBMC to generate the OBMC-based predictor, the video coder generates an intra-based predictor by performing intra prediction using the intra prediction information of one or more neighboring blocks (804). That is, for each boundary subblock that is adjacent to an intra-predicted block, the video coder uses the intra prediction information (e.g,, intra prediction mode) of the adjacent intra-predicted block to generate a prediction for the boundary subblock. The video coder includes the prediction for the boundary subblock in the intra-based predictor. The final step that performs intra prediction is also applicable if a corresponding neighboring block is intra prediction block or contains intra prediction information,(0160] The video coder blends the OBMC-based predictor and the intra-based predictor to generate a blended predictor (806).. The video coder may blend inter and intra subblocks is a manner similar to the blending of inter and inter sub-blocks. The video coder may then then encode or decode the current block based on the blended predictor (808), For example, as part of encoding the current, block, the video coder may generate residual data based on the blended predictor and original samples of the current block. The video coder may apply a transform to the residual data to generate transform data, which may then be quantized and entropy encoded. As part of decoding the current block, the video coder may add the blended predictor to residual data to generate reconstructed video data for the current block,(0161] FIG. 9 is a flowchart illustrating an example operation for OBMC with EIC and intra prediction, in accordance with one or more techniques of this disclosure. In the example of FIG. 9, a video coder (e.g,, video encoder 200 or video decoder 300) performs motion compensation using motion information of a current block to generate an initial motion-compensated predictor (900). In other words, the video coder may perform motion compensation using the motion information (e.g., one or more motion vectors) ofthe carrent block to generate the initial motion-compensated predictor for the current block. The motion compensation may be unidirectional or bidirectional

[0162] Next, the video coder performs OBMC to generate an OBMC-based predictor for the current block based on the initial motion-compensated predictor (902). For example, for each left boundary subblock of the current block, if a neighboring block that is adjacent to a le ft boundary of the left boundary subblock is inter predicted and the motion information of the neighboring block is different from the motion information of the left boundary subblack, the video coder generates a prediction sample block using the motion information of the neighboring block based on the position of the left boundary subblock. Similarly, for each top boundary' subblock of the current block, if a neighboring block that is adjacent to a top boundary of the top boundary subblock is inter predicted and the motion information of the neighboring block is different from the motion information of the top boundary subblock, the video coder generates a prediction sample block using the motion information of the neighboring block based on the position of the top boundary' subblock. The video coder generates the OBMC-based predictor based on the initial motion-compensated predictor and the generated prediction sample blocks of the left and top boundary subblocks. In the OBMC-based predictor, samples that are adjacent to a left boundary of a left boundary subblock are a blend of the corresponding prediction samples in the initial motion-compensated predictor and the generated prediction sample block for the left boundary subblock and samples that are adjacent to a top boundary of a top boundary subblock are a blend of the corresponding prediction samples in the initial motion-compensated predictor and the generated prediction sample block for die top boundary subblock. In some examples, the video coder performs inner subblock OBMC as part of generating the OBMC-based predictor.

[0163] After the video coder performs OBMC to generate the OBMC-based predictor, the video coder determines LIC parameters with reference to neighboring reconstructed samples (904). The video coder may then apply the LIC parameters to the OBMC-based predictor for the current block to generate an LIC-based predictor for the current block (906). The video coder may determine and apply the LIC parameters in the manner described above.

[0164] Next, the video coder generates an infra-based predictor by performing infra prediction using the intra prediction informati n of one or more neighboring blocks (908). That is, for each boundary subblock that is adjacent to an intra-predicted block, the video coder uses the intra prediction information (e.g., intra prediction mode) of the adjacentintra-predicted block to generate a prediction for the boundary subblock. For example, the video coder may use reconstructed samples of blocks or subblocks above and / or left of the boundary subblock, along with a directional intra prediction mode, to generate the prediction for the boundary subblock. The video coder includes the prediction for the boundary subblock in the intra-based predictor. For instance, the video decoder may set values of samples corresponding to the boundary Subblock in the intra-based predictor to values Of samples in the prediction for the boundary subblock. The final step that performs intra prediction is also applicable if a corresponding neighboring block is intra prediction block or contains intra prediction information.(0165] The video coder blends the LIC-based predictor and the intra-based predictor to generate a blended predictor (910). For instance, the video coder may generate the blended predictor such that each sample of the blended predictor is based on conesponding samples of the LIC-based predictor and the intra-based predictor. The video coder may then then encode or decode the current block based on the blended predictor (912). For example, as part of encoding the current block, the video coder may generate residual data based on the blended predictor and original samples of the current block. The video coder may apply a transform to the residual data to generate transform data, which may then be quantized and entropy encoded. As part of decoding the current block, the video coder may add the blended predictor to residual data io generate reconstructed video data for the current block0166 The following numbered clauses illustrate one or more aspects of the devices and techniques described in this disclosure.(0167] Clause 1A. A method of coding video data, the method comprising: performing motion compensation using motion information of a current block to generate a first predictor; performing inner subblock overlapped-block motion compensation (OBMC) to generate a second predictor for the current block based on the first predictor; using motion information of one or more neighboring blocks to perform motion compensation and perform blending with the second predictor to generate a third predictor for the current block; applying local illumination compensation (LIC) parameters to the third predictor to generate a fourth predictor for the current block; and encoding or decoding the current block based on the fourth predictor for the current block.(0168] Clause 2A. A method of coding video data, the method comprising: per forming motion compensation using motion information of a current block to generate a first predictor; performing inner subblock overlapped-block motion compensation(OBMC) to generate a second predictor for the current block based on the first predictor; using motion information of one or more neighboring blocks to perform motion compensation and perform blending with the second predictor to generate a third predictor for the current block; performing intra prediction using intra prediction information of one or more neighboring blocks and blending with the third predictor to generate a fourth predictor for the current block; and encoding or decoding the current block based on the fourth predictor for the current block,(0169] Clause 3A. A method of coding video data, the method comprising: performing motion compensation using motion information of a current block to generate a first predictor; performing inner subblock overlapped-block motion compensation (OBMC) to generate a second predictor for the current block based on the first predictor; using motion information of one or more neighboring blocks to perform motion compensation and blending with the second predictor to generate a third predictor for the current block; applying local illumination compensation (LIC) parameters to the third predictor to generate a fourth predictor for the current block; performing intra prediction using intra prediction information of one or more neighboring blocks and blending with the fourth predictor to generate a fifth predictor; and encoding or decoding the current block based on the fifth predictor for the current block,(0170] Clause 4A. A device for coding video data, the device comprising one or more means for performing the method of any of clauses I A-3 A.

[0171] Clause 5A, The device of clause 4A, wherein the one or more means comprise one or more processors implemented in circuitry.(0172] Clause 6A. The device of any of clauses 4 A and 5 A, further comprising a memory to store the video data.|0173] Clause 7A. The device of any of clauses 4A-6A, further comprising a display configured to display decoded video data.(0174] Clause 8A. The device of any of clauses 4A-7A, wherein the device comprises one or more of a camera, a computer, a mobile device, a broadcast recei ver device, or a set-top box.(0175] Clause 9 A. The de vice of any of cla uses 4A-8A, wherein the device comprises a video decoder.(0176] Clause 10A. The device of any of clauses 4A-9 A, wherein the device comprises a video encoder.

[0177] Clause I LA. A computer-readable storage medium having stored, thereon instructions that, when executed, cause one or more processors to perform the method of any of clauses 1 A-3A.

[0178] Clause IB. A method of coding video data, the method comprising: performing motion compensation using motion information of a current block to generate a first predictor; performing overlapped block motion compensation (OBMC) to generate a second predictor based on the first predictor; deriving local illumination compensation (LIC) parameters based on neighboring reconstructed samples; after performing OBMC, applying the LIC parameters to the second predictor to generate a third predictor for the current block; and encoding or decoding the current block based on the third predictor.

[0179] Clause 2B. The method of Clause IB, wherein performing OBMC comprises: performing inner subblock OBMC to generate a fourth predictor; and performing boundary OBMC, wherein performing boundary OBMC comprises performing motion compensation and blending results of the motion compensation with the fourth predictor to generate the second predictor.

[0180] Clause 3 B. The method of any of Clauses IB-2B, wherein the current block is a first block, the method further comprising: performing motion compensation using motion information of a second block to generate a fourth predictor; performing OBMC to generate a fifth predictor based on the fourth predictor; after performing OBMC to generate the fifth predictor, performing intra prediction using intra prediction information of one or more neighboring blocks of the second block and blending with the fifth predictor to generate a sixth predictor for die second block; and encoding or decoding the second block based on the sixth predictor for the second block.

[0181] ( Clause 4B, The method of any of Clauses 1B-2B, wherein the current block is a first block, the method further comprising: performing motion compensation using motion infonnaifon of a second block to generate a fourth predictor; performing OBMC to generate a fifth predictor based on the fourth predictor; determining second local illumination compensation (LIC) parameters based on neighboring reconstructed samples; applying LIC using the second LIC parameters to the fifth predictor to generate a sixth predictor for the second block; performing intra prediction using intra prediction information of one or more neighboring blocks and blending with the sixth predictor to generate a seventh predictor; and encoding or decoding the second block based on the seventh predictor for the second block.[01821 Clause 5B, A device for coding video data, the device comprising: a memory; and one or more processors configured to cause the device to: perform motion compensation using motion information of a current block to generate a first predictor; perform overlapped block motion compensation (OBMC) to generate a second predictor based on the first predictor; derive local illumination compensation (LIC) parameters based on neighboring reconstructed samples; after performing OBMC, applying the LIC parameters to the second predictor to generate a third predictor for the current block; and encode or decode the current block based on the third predictor.|0183| Clause 6B. 'Fite device of Clause 5B, wherein to cause the device to perform OBMC, the one or more processors are configured to cause the device to: perform inner subblock OBMC to generate a fourth predictor; and perform boundary OBMC, wherein performing boundary OBMC comprises performing motion compensation and blending results of the motion compensation with the fourth predictor to generate the second predictor.

[0184] Clause 7B. The device of any of Clauses 5B-6B, wherein the current block is a first block and the one or more processors are further configured to cause the device to: perform motion compensa tion using motion information of a second block to generate a fourth predictor; perform OBMC to generate a fifth predictor based on the fourth predictor: after performing OBMC to generate the fifth predictor, performing intra prediction using intra prediction information of one or more neighboring blocks of the second block and blending with the fifth predictor to generate a sixth predictor for the second block; and encode or decode the second block based on the sixth predictor for the second block.

[0185] Clause 8B. The device of any of Clauses 5B-6B, wherein the current block is a first block, the one or more processors are further configured to cause the device to: perform motion compensa tion using motion information of a second block to generate a fourth predictor; perform OBMC to generate a fifth predictor based on the fourth predictor: determine second local illumination compensation (LIC) parameters based on neighboring reconstructed samples; apply LIC using the second LIC parameters to the fifth predictor to generate a sixth predictor for the second block; perform intra prediction using intra prediction information of one or more neighboring blocks and blending with the sixth predictor to generate a seventh predictor; and encode or decode the second block based on the seventh predictor for the second block:

[0186] Clause 9B, The device of any of Clauses 5B-8B, further comprising a display configured to display decoded video data,

[0187] Clause I0B, The device of any of Clauses 5B-9B, wherein the device comprises one or more of a camera, a computer, a mobile device, a broadcast receiver device, or a set-top box,

[0188] Clause 11B, The de vice of any of Clauses 5B-10B, wherein the device comprises a video decoder,

[0189] Clause I2B. The device of any of Clauses 5B-11B, wherein the device compr ises a video encoder.

[0190] Clause 13B, A non-transitory computer-readable storage medium having stored thereon instructions that, when executed, cause one or more processors to: perform motion compensation using motion information of a current block to generate a first predictor; perforin overlapped block motion compensation (OBMC) to generate a second predictor based on the first predictor; derive local illumination compensation (LIC) parameters based on neighboring reconstructed samples; after performing OBMC, apply the LIC parameters to the second predictor to generate a third predictor for the current block; and encode or decode the current block based on the third predictor.

[0191] Clause 14B. The non-transitory computer-readable storage medium of Clause 13B, wherein to perform OBMC. and execu tion of the instructions causes the oneor more processors to: perform inner subblock OBMC to generate a fourth predictor; and perform boundary OBMC, wherein performing boundary OBMC comprises performing motion compensation and blending results of the motion compensation with the fourth predictor to generate the second predictor,

[0192] Clause 15B, The non-transitory computer-readable storage medium of any of Clauses 13B-14B, wherein the current block is a first block, and execution of the instructions further causes the one or more processors to: perform motion compensation using motion information of a second block to generate a fourth predictor; perform OBMC to generate a fifth predictor based on the fourth predictor; after performing OBMC to generate the fifth predictor, perform intra prediction using intra prediction information of one or more neighboring blocks of the second block and blending with the fifth predictor to generate a sixth predictor for the second block; and encode or decode the second block based on the sixth predictor for the second block.

[0193] Clause 16B. The non-transitory computer-readable storage medium of any of Clauses 13B-14B, wherein the current block is a first block, and execution of theinstructions further causes the one or more processors to: perform motion compensation using motion information of a second block to generate a fourth predictor; perform OBMC to generate a fifth predictor based on the fourth predictor; determine second local illumination compensation (LIC) parameters based on neighboring reconstructed samples; apply LIC using the second LIC parameters to the fifth predictor to generate a sixth predictor for the second block; perform intra prediction using intra prediction information of one or more neighboring blocks and blending with the sixth predictor to generate a seventh predictor; and encode or decode the second block based on the seventh predictor for the second block.|0194| It is to be recognized that depending on the example, certain acts or events of any of the techniques described herein can be performed in a different sequence, may be added, merged, or left out altogether (e,g., not all described acts or events ate necessary for the practice of the techniques). Moreover, in certain examples, acts or events may be performed concurrently, e.g., through multi-threaded processing, interrupt processing, or multiple processors, rather than sequentially.

[0195] 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 over as one or more instructions or code on a computer-readable medium and executed by a hardware-based processing unit. Computer-readable media max' include computer-readable storage media,, which corresponds to a tangible medium such as data storage media, or communication media including any medium that facilitates transfer of a computer program from one place to another, e.g., according to a communication protocol. In this manner, computer-readable media generally may correspond to (1) tangible computer-readable storage media which is non-transitory or (2) a communication medium such as a signal or carrier wave. 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, code and / or data structures for implementation of the techniques described in this disclosure. A computer program product may inelude a computer-readable medium.

[0016] By way of example, and not limitation, such computer-readable storage media may include one or more of 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 desired program code in the form of instructions or data structures and that can be accessed by a computer. Also, any connection isproperly termed a computer-readable medium. For example, if instructions are transmitted from a website, server, or other remote source using a coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless technologies such as infrared, radio, and microwave, then the coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave arc included in the defini tion of medium. It should be understood, however, that computer-readable Storage media and data storage media do not include connections, carrier waves, signals, or other transitory media, but are instead directed to non-transitory, tangible storage media. Disk and disc, as used herein, includes compact disc (CD), laser disc, optical disc, digital versatile disc (DVD), floppy disk and Blu-ray disc, where disks usually reproduce data magnetically, while discs reproduce data optically with lasers. Combinations of the above should also be included within the scope of computer-readable media.(0197] Instructions may be executed by one or more processors, such as one or more DSPs, general purpose microprocessors, ASICs, FPGAs, ar other equivalent integrated or discrete logic circuitry. Accordingly, the terms “processor” and “processing circuitry,” as used herein may refer to any of the foregoing structures or any other structure suitable for implementation of the techniques described herein. In addition, in some aspects, the functionality described herein may be provided within dedicated hardware and / or software modules configured for encoding and decoding, or incorporated in a combined codec. Also, the techniques could be fully implemented in one or more circuits or logic elements.(0198] The techniques of this disclosure may be implemented in a wide variety of devices or apparatuses, including a wireless handset, an integrated circuit (1C) or a set of ICs (e.g., a chip set). Various components, modules, or units are described in this disclosure to emphasize functional aspects of devices configured to perform the disclosed techniques, but do not necessarily require realization by different hardware units. Rather, as described above, various units may be combined in a codec hardware unit or provided by a col lection of interoperative hardware units, including one or more processors as described above, in conjunction with suitable software and / or firmware.(01 9] Where a phrase similar to “at least one of A, B, and C is used in the claims, it is intended that the phrase be interpreted to mean that A alone may be present in an embodiment; B alone may be present in an embodiment; C alone may be present in an embodiment; or that any combination of the elements A, B, and C may be present in a single embodiment, for example, A and B, A and C, B and C, or A and B and C. Wherea phrase similar to ‘'one or more processors configured to X, V, and Z” is used in the claims, it is intended that the phrase be interpreted to mean at least: that a processor alone may perform functions X, Y, and Z; that two or more processors (e.g„ processors A and B) may collectively perform functions X, Y, and Z; that a first processor A may perform functions X and ¥ and a second processor may perform function Z; or that a first processor A may perform function X, a second processor may perform function Y, and a third processor may perform function Z,|0200 Various examples have been described. These and other examples are within the scope of the following c laims.

Claims

WHAT IS CLAIMED IS:

1. A method of coding v deo data, the method comprising:performing motion compensation using morion information of a current block to generate a first predictor;performing overlapped block motion compensation (OBMC) to generate a second predictor based on the first predictor;deriving local illumination compensation (LIC) parameters based on neighboring reconstructed samples;after performing OBMC. applying the LIC parameters to the second predictor to generate a third predictor for the current block; andencoding or decoding the current block based on the third predictor.

2. The method of claim 1, wherein performing OBMC comprises:performing inner subblock OBMC to generate a fourth predictor; and performing boundary' OBMC, wherein performing boundary OBMC comprises performing motion compensation and blending results of the motion compensation with the fourth predictor to generate the second predictor.

3. The method of claim I, wherein the current block is a first block, the method further comprising:performing motion compensation using morion information of a second block to generate a fourth predictor;performing OBMC to generate a fifth predictor based on the fourth predictor; after performing OBMC to generate the fifth predictor, performing intra prediction using intra prediction information of one or more neighboring blocks of the second block and blending with the fifth predictor to generate a sixth predictor for the second block; andencoding or decoding the second block based on the sixth predictor for the second block.

4. The method of claim I, wherei n the current block is a first block, the method further comprising:performing motion compensation using motion information of a second block to generate a fourth predictor;performing OBMC to generate a fifth predictor based on the fourth predictor; determining second local illumination compensation (LIC) parameters based on neighboring reconstructed samples;applying LIC1using the second LIC parameters to the fifth predictor to generate a sixth predictor for the second block;performing intra predi c tion using intra prediction information of one or more neighboring blocks and blending with the sixth predictor to generate a seventh predictor; andencoding or decoding the second block based on the seventh predictor for the secondblock.

5. A device for coding video data, the device comprising;a memory; andone or more processors configured to cause the device to:perform motion compensation using motion information of a curren t block to generate a first predictor;perform overlapped block motion compensation (OBMC) to generate a second predictor based on the first predictor;derive local illumination compensation (LIC) parameters based on neighboring reconstructed samples;after performing OBMC, applying the LIC parameters to the second predictor to generate a third predictor for the current block; andencode or decode the current block based on the third predictor,6, The device of claim 5, wherein to cause the device to perform OBMC, the one or more processors are configured to cause the device to:perform inner subblock OBMC to generate a fourth predictor; andperform boundary OBMC, wherein performing: boundary OBMC comprises performing motion compensation and blending results of the motion compensa tion with the fourth predictor to generate the second predictor.

7. The device of claim 5, wherein the current block is a first block and the one or more processors are further configured to cause the device to:perform motion compensation using motion information of a second block to generate a fourth predictor;perform OBMC to generate a fifth predictor based on the fourth predictor; after performing OBMC to generate the fifth predictor, performing intra pred iction using intra prediction information of one or more neighboring blocks of the second block and blending with the fifth predictor to generate a sixth predictor for the second block; andencode or decode the second block based on the sixth predictor for the second block.The device of claim 5, wherein the current block is a first block, the one or more processors are further configured to cause the device to:perform motion compensation using motion information of a second block to generate a fourth predictor;perform OBMC to generate a fifth predictor based on the fourth predictor; determine second local illumination compensation (LIC) parameters based on neighboring reconstructed samples;apply LIC using the second LIC parameters to die fifth predictor to generate a sixth predictor for the second block;perform intra predi ction using intra predi ction in formation of one or more neighboring blocks and blending with the sixth predictor to generate a seventh predictor; andencode or decode the second block based on the seventh predictor for the second block.

9. The device of claim 5, further comprising a display configured to display decoded video data.

10. The device of claim 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.

11. The device of claim 5, wherein the device comprises a video decoder.

12. The device of claim 5, wherein the device comprises a video encoder.

13. A non-transitory computer-readable storage medium having stored thereon instructions that, when executed, cause one or more processors to:perform motion compensa tion using motion information of a current block to generate a first predictor;perform overlapped block motion compensation (OBMC) to generate a second predictor based on the first predictor;deri ve focal illumination compensation (LIC) parameters based on neighboring reconstructed samples;after performing OBMC, apply the LIC parameters to the second predictor to generate a third predictor for the current block, andencode or decode the current block based on the third predictor.

14. The non-transitory computer-readable storage medium of claim 13, wherein to perform OBMC, arid execution of the instructions causes the one or more processors to:perform inner subblock OBMC to generate a fourth predictor; andperform boundary OBMC, wherein performing boundary OBMC comprises performing motion compensation and b tending results of the motion compensation with the fourth predictor to generate the second predictor.

15. The non-transitory computer-readable storage medium of claim 13, wherein the current block is a fir st block, and execution of the instructions further causes the one or more processors to:perform motion compensation using motion information of a second block to generate a fourth predictor;perform OBMC to generate a fifth predictor based on the fourth predictor; after performing OBMC to generate the fifth predictor, perform intra prediction using intra prediction information of one or more neighboring blocks of the second block and blending with the fifth predictor to generate a sixth predictor for the second block; andencode or decode the second block based on the sixth predictor for the second block.

16. The non-transitory computer-readable storage medium of claim 13, wherein the current block is a first block, and execution of the instructions further causes the one or more processors to:perform motion compensation using motion information of a second block to generate a fourth predictor;perform OBMC to generate a fifth predictor based on the fourth predictor; determine second local illumination compensation (I JC) parameters based on neighboring reconstructed samples;apply LIC using the second LIC parameters to the fifth predictor to generate a sixth predictor for the second block;perform intra prediction using intra prediction information of one or more neighboring blocks and blending with the sixth predictor to generate a seventh predictor; andencode or decode the second block based on the seventh predictor for the second block.

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