IDVC_ 2023P00519WO PATENT BI-PREDICTION INTRA BLOCK COPY WITH LOCAL ILLUMINATION COMPENSATION CROSS-REFERENCE TO RELATED APPLICATIONS [0001] This application claims the benefit of European Patent Application 23306079.7, filed June 30, 2023, the disclosure of which is incorporated herein by reference in its entirety. BACKGROUND [0002] Video coding systems may be used to compress digital video signals, e.g., to reduce the storage and/or transmission bandwidth needed for such signals. Video coding systems may include, for example, block-based, wavelet-based, and/or object-based systems. SUMMARY [0003] Systems, methods, and instrumentalities are disclosed for performing video coding using intra block copy (IBC) bi-prediction with bi-predictive local Illumination compensation (LIC). A bi-predictive LIC model may be derived for a CU coded in IBC mode, e.g., similar to a method for inter CU. A bi-predictive LIC mode may be derived/signaled at CU-level, for example, according to whether the CU is in block vector prediction (BVP)-merge mode or in bi-predictive IBC merge mode. A bi-predictive LIC IBC mode may be controlled, for example, with high-level control(s). [0004] A video coding device (e.g., decoder) may implement a method for video coding using IBC bi- prediction with bi-predictive LIC. The video coding device may determine that bi-predictive LIC is enabled for a current block. The video coding device may determine that the current block is coded using IBC mode. The video coding device may obtain a first LIC parameter based on a first block vector associated with the current block. The video coding device may obtain a second LIC parameter based on a second block vector associated with the current block. The video coding device may decode the current block based on the first and second LIC parameter. [0005] Bi-predictive LIC enabled for the current block may be determined based on a bi-predictive LIC indication associated with the current block. The video coding device (e.g., decoder) may (e.g., further) obtain a first template of a first reference block based on the first block vector. The first LIC parameter may be derived based on a template of the current block and the first template of the first reference block. The
IDVC_ 2023P00519WO PATENT video coding device may (e.g., further) obtain a second template of a second reference block based on the second block vector. The second LIC parameter may be derived based on the template of the current block and the second template of the second reference block. The template of the current block may include the top template, the left template, or both. Decoding the current block based on the first and second LIC parameter may include, for example, obtaining a first prediction block based on the first block vector; refining the first prediction block based on the first LIC parameter; obtaining a second prediction block based on the second block vector; refining the second prediction block based on the second LIC parameter; and predicting the current block based on the first refined prediction block and the second refined prediction block. The first LIC parameter may include an LIC scaling factor and/or an LIC offset. [0006] A video coding device (e.g., encoder) may implement a method for video coding using IBC bi- prediction with bi-predictive LIC. The video coding device may determine to enable bi-predictive LIC for a current block. The video coding device may determine to code the current block using IBC mode. The video coding device may obtain a first LIC parameter based on a first block vector associated with the current block. The video coding device may obtain a second LIC parameter based on a second block vector associated with the current block. The video coding device may encode the current block based on the first and second LIC parameter. [0007] The video coding device (e.g., encoder) may include, in video data, a bi-predictive LIC indication associated with the current block to indicate that bi-predictive LIC is enabled for the current block. The video coding device may (e.g., further) obtain a first template of a first reference block based on the first block vector. The first LIC parameter may be derived based on a template of the current block and the first template of the first reference block. The video coding device may obtain a second template of a second reference block based on the second block vector. The second LIC parameter may be derived based on the template of the current block and the second template of the second reference block. The template of the current block may include the top template and/or the left template. Encoding the current block based on the first and second LIC parameter may include, for example, obtaining a first prediction block based on the first block vector; refining the first prediction block based on the first LIC parameter; obtaining a second prediction block based on the second block vector; refining the second prediction block based on the second LIC parameter; generating a residual of the current block based on the first refined prediction block and the second refined prediction block; and including an indication of the residual in video data. The first LIC parameter may include an LIC scaling factor and/or an LIC offset. [0008] In examples, a video decoding device may determine that a current block is coded using block- vector-based prediction mode. The video decoding device may determine that bi-predictive LIC is enabled for the current block. In examples, the bi-predictive LIC being enabled for the current block may be determined based on a bi-predictive LIC indication associated with the current block. The video decoding
IDVC_ 2023P00519WO PATENT device may determine that the current block is coded using a block-vector-based prediction mode (e.g., an IBC mode). The video decoding device may obtain a first LIC parameter based on a first block vector associated with the current block and a second LIC parameter based on a second block vector associated with the current block. The video decoding device may decode the current block based on the first and second LIC parameters. [0009] In examples, the video decoding device may obtain a first template of a first reference block based on the first block vector. The first LIC parameter may be derived based on a template of the current block and the first template of the first reference block. The video decoding device may obtain a second template of a second reference block based on the second block vector. The second LIC parameter may be derived based on the template of the current block and the second template of the second reference block. In examples, the template of the current block may include at least one of a top template or a left template. [0010] In examples, decoding the current block based on the first and second LIC parameter may include (e.g., further include) obtaining a first prediction block based on the first block vector, refining the first prediction block based on the first LIC parameter, obtaining a second prediction block based on the second block vector, refining the second prediction block based on the second LIC parameter, and predicting the current block based on the first refined prediction block and the second refined prediction block. In examples, the first LIC parameter may include at least one of an LIC scaling factor or an LIC offset. [0011] A video encoding device may determine to code a current block using block-vector-based prediction mode (e.g., an IBC mode). The video encoding device may determine to enable bi-predictive LIC for the current block. In examples, the video encoding device may include, in video data, a bi-predictive LIC indication associated with the current block to indicate that the bi-predictive LIC is enabled for the current block. The video coding device may obtain a first LIC parameter based on a first block vector associated with the current block and a second LIC parameter based on a second block vector associated with the current block. The video encoding device may encode the current block based on the first and second LIC parameters. [0012] In examples, the video encoding device may obtain a first template of a first reference block based on the first block vector. The first LIC parameter may be derived based on a template of the current block and the first template of the first reference block. The video encoding device may obtain a second template of a second reference block based on the second block vector. The second LIC parameter may be derived based on the template of the current block and the second template of the second reference block. In examples, the template of the current block may include at least one of a top template or a left template.
IDVC_ 2023P00519WO PATENT [0013] In examples, decoding the current block based on the first and second LIC parameter may include (e.g., further include) obtaining a first prediction block based on the first block vector, refining the first prediction block based on the first LIC parameter, obtaining a second prediction block based on the second block vector, refining the second prediction block based on the second LIC parameter, generating a residual of the current block based on the first refined prediction block and the second refined prediction block, and including an indication of the residual in video data. In examples, the first LIC parameter may include at least one of an LIC scaling factor or an LIC offset. [0014] Systems, methods, and instrumentalities described herein may involve a decoder. In some examples, the systems, methods, and instrumentalities described herein may involve an encoder. In some examples, the systems, methods, and instrumentalities described herein may involve a signal (e.g., from an encoder and/or received by a decoder). A computer-readable medium may include instructions for causing one or more processors to perform methods described herein. A computer program product may include instructions which, when the program is executed by one or more processors, may cause the one or more processors to carry out the methods described herein. BRIEF DESCRIPTION OF THE DRAWINGS [0015] FIG.1A is a system diagram illustrating an example communications system in which one or more disclosed embodiments may be implemented. [0016] FIG.1B is a system diagram illustrating an example wireless transmit/receive unit (WTRU) that may be used within the communications system illustrated in FIG.1A according to an embodiment. [0017] FIG.1C is a system diagram illustrating an example radio access network (RAN) and an example core network (CN) that may be used within the communications system illustrated in FIG.1A according to an embodiment. [0018] FIG.1D is a system diagram illustrating a further example RAN and a further example CN that may be used within the communications system illustrated in FIG.1A according to an embodiment. [0019] FIG.2 illustrates an example video encoder. [0020] FIG.3 illustrates an example video decoder. [0021] FIG.4 illustrates an example of a system in which various aspects and examples may be implemented. [0022] FIG.5 illustrates an example of current coding tree unit (CTU) processing order and available reference samples in the current and left CTU. [0023] FIG.6 illustrates an example of padding candidates for the replacement of the zero-vector in the IBC list.
IDVC_ 2023P00519WO PATENT [0024] FIG.7 illustrates an example of an extended reference region for IBC. [0025] FIG.8 illustrates an example of an intra template matching search area. [0026] FIG.9 illustrates an example of multiple intra template matching prediction (IntraTMP) candidates. [0027] FIG.10 illustrates an example of a spatial part of a filter. [0028] FIG.11 illustrates an example of the reference area that may be used to derive the filter coefficients. DETAILED DESCRIPTION [0029] A more detailed understanding may be had from the following description, given by way of example in conjunction with the accompanying drawings. [0030] FIG.1A is a diagram illustrating an example communications system 100 in which one or more disclosed embodiments may be implemented. The communications system 100 may be a multiple access system that provides content, such as voice, data, video, messaging, broadcast, etc., to multiple wireless users. The communications system 100 may enable multiple wireless users to access such content through the sharing of system resources, including wireless bandwidth. For example, the communications systems 100 may employ one or more channel access methods, such as code division multiple access (CDMA), time division multiple access (TDMA), frequency division multiple access (FDMA), orthogonal FDMA (OFDMA), single-carrier FDMA (SC-FDMA), zero-tail unique-word DFT-Spread OFDM (ZT UW DTS-s OFDM), unique word OFDM (UW-OFDM), resource block-filtered OFDM, filter bank multicarrier (FBMC), and the like. [0031] As shown in FIG.1A, the communications system 100 may include wireless transmit/receive units (WTRUs) 102a, 102b, 102c, 102d, a RAN 104/113, a CN 106/115, a public switched telephone network (PSTN) 108, the Internet 110, and other networks 112, though it will be appreciated that the disclosed embodiments contemplate any number of WTRUs, base stations, networks, and/or network elements. Each of the WTRUs 102a, 102b, 102c, 102d may be any type of device configured to operate and/or communicate in a wireless environment. By way of example, the WTRUs 102a, 102b, 102c, 102d, any of which may be referred to as a “station” and/or a “STA”, may be configured to transmit and/or receive wireless signals and may include a user equipment (UE), a mobile station, a fixed or mobile subscriber unit, a subscription-based unit, a pager, a cellular telephone, a personal digital assistant (PDA), a smartphone, a laptop, a netbook, a personal computer, a wireless sensor, a hotspot or Mi-Fi device, an Internet of Things (IoT) device, a watch or other wearable, a head-mounted display (HMD), a vehicle, a drone, a medical device and applications (e.g., remote surgery), an industrial device and applications (e.g., a robot and/or
IDVC_ 2023P00519WO PATENT other wireless devices operating in an industrial and/or an automated processing chain contexts), a consumer electronics device, a device operating on commercial and/or industrial wireless networks, and the like. Any of the WTRUs 102a, 102b, 102c and 102d may be interchangeably referred to as a UE. [0032] The communications systems 100 may also include a base station 114a and/or a base station 114b. Each of the base stations 114a, 114b may be any type of device configured to wirelessly interface with at least one of the WTRUs 102a, 102b, 102c, 102d to facilitate access to one or more communication networks, such as the CN 106/115, the Internet 110, and/or the other networks 112. By way of example, the base stations 114a, 114b may be a base transceiver station (BTS), a Node-B, an eNode B, a Home Node B, a Home eNode B, a gNB, a NR NodeB, a site controller, an access point (AP), a wireless router, and the like. While the base stations 114a, 114b are each depicted as a single element, it will be appreciated that the base stations 114a, 114b may include any number of interconnected base stations and/or network elements. [0033] The base station 114a may be part of the RAN 104/113, which may also include other base stations and/or network elements (not shown), such as a base station controller (BSC), a radio network controller (RNC), relay nodes, etc. The base station 114a and/or the base station 114b may be configured to transmit and/or receive wireless signals on one or more carrier frequencies, which may be referred to as a cell (not shown). These frequencies may be in licensed spectrum, unlicensed spectrum, or a combination of licensed and unlicensed spectrum. A cell may provide coverage for a wireless service to a specific geographical area that may be relatively fixed or that may change over time. The cell may further be divided into cell sectors. For example, the cell associated with the base station 114a may be divided into three sectors. Thus, in one embodiment, the base station 114a may include three transceivers, i.e., one for each sector of the cell. In an embodiment, the base station 114a may employ multiple-input multiple output (MIMO) technology and may utilize multiple transceivers for each sector of the cell. For example, beamforming may be used to transmit and/or receive signals in desired spatial directions. [0034] The base stations 114a, 114b may communicate with one or more of the WTRUs 102a, 102b, 102c, 102d over an air interface 116, which may be any suitable wireless communication link (e.g., radio frequency (RF), microwave, centimeter wave, micrometer wave, infrared (IR), ultraviolet (UV), visible light, etc.). The air interface 116 may be established using any suitable radio access technology (RAT). [0035] More specifically, as noted above, the communications system 100 may be a multiple access system and may employ one or more channel access schemes, such as CDMA, TDMA, FDMA, OFDMA, SC-FDMA, and the like. For example, the base station 114a in the RAN 104/113 and the WTRUs 102a, 102b, 102c may implement a radio technology such as Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access (UTRA), which may establish the air interface 115/116/117 using wideband CDMA (WCDMA). WCDMA may include communication protocols such as High-Speed Packet
IDVC_ 2023P00519WO PATENT Access (HSPA) and/or Evolved HSPA (HSPA+). HSPA may include High-Speed Downlink (DL) Packet Access (HSDPA) and/or High-Speed UL Packet Access (HSUPA). [0036] In an embodiment, the base station 114a and the WTRUs 102a, 102b, 102c may implement a radio technology such as Evolved UMTS Terrestrial Radio Access (E-UTRA), which may establish the air interface 116 using Long Term Evolution (LTE) and/or LTE-Advanced (LTE-A) and/or LTE-Advanced Pro (LTE-A Pro). [0037] In an embodiment, the base station 114a and the WTRUs 102a, 102b, 102c may implement a radio technology such as NR Radio Access , which may establish the air interface 116 using New Radio (NR). [0038] In an embodiment, the base station 114a and the WTRUs 102a, 102b, 102c may implement multiple radio access technologies. For example, the base station 114a and the WTRUs 102a, 102b, 102c may implement LTE radio access and NR radio access together, for instance using dual connectivity (DC) principles. Thus, the air interface utilized by WTRUs 102a, 102b, 102c may be characterized by multiple types of radio access technologies and/or transmissions sent to/from multiple types of base stations (e.g., a eNB and a gNB). [0039] In other embodiments, the base station 114a and the WTRUs 102a, 102b, 102c may implement radio technologies such as IEEE 802.11 (i.e., Wireless Fidelity (WiFi), IEEE 802.16 (i.e., Worldwide Interoperability for Microwave Access (WiMAX)), CDMA2000, CDMA20001X, CDMA2000 EV-DO, Interim Standard 2000 (IS-2000), Interim Standard 95 (IS-95), Interim Standard 856 (IS-856), Global System for Mobile communications (GSM), Enhanced Data rates for GSM Evolution (EDGE), GSM EDGE (GERAN), and the like. [0040] The base station 114b in FIG.1A may be a wireless router, Home Node B, Home eNode B, or access point, for example, and may utilize any suitable RAT for facilitating wireless connectivity in a localized area, such as a place of business, a home, a vehicle, a campus, an industrial facility, an air corridor (e.g., for use by drones), a roadway, and the like. In one embodiment, the base station 114b and the WTRUs 102c, 102d may implement a radio technology such as IEEE 802.11 to establish a wireless local area network (WLAN). In an embodiment, the base station 114b and the WTRUs 102c, 102d may implement a radio technology such as IEEE 802.15 to establish a wireless personal area network (WPAN). In yet another embodiment, the base station 114b and the WTRUs 102c, 102d may utilize a cellular-based RAT (e.g., WCDMA, CDMA2000, GSM, LTE, LTE-A, LTE-A Pro, NR etc.) to establish a picocell or femtocell. As shown in FIG.1A, the base station 114b may have a direct connection to the Internet 110. Thus, the base station 114b may not be required to access the Internet 110 via the CN 106/115. [0041] The RAN 104/113 may be in communication with the CN 106/115, which may be any type of network configured to provide voice, data, applications, and/or voice over internet protocol (VoIP) services
IDVC_ 2023P00519WO PATENT to one or more of the WTRUs 102a, 102b, 102c, 102d. The data may have varying quality of service (QoS) requirements, such as differing throughput requirements, latency requirements, error tolerance requirements, reliability requirements, data throughput requirements, mobility requirements, and the like. The CN 106/115 may provide call control, billing services, mobile location-based services, pre-paid calling, Internet connectivity, video distribution, etc., and/or perform high-level security functions, such as user authentication. Although not shown in FIG.1A, it will be appreciated that the RAN 104/113 and/or the CN 106/115 may be in direct or indirect communication with other RANs that employ the same RAT as the RAN 104/113 or a different RAT. For example, in addition to being connected to the RAN 104/113, which may be utilizing a NR radio technology, the CN 106/115 may also be in communication with another RAN (not shown) employing a GSM, UMTS, CDMA 2000, WiMAX, E-UTRA, or WiFi radio technology. [0042] The CN 106/115 may also serve as a gateway for the WTRUs 102a, 102b, 102c, 102d to access the PSTN 108, the Internet 110, and/or the other networks 112. The PSTN 108 may include circuit- switched telephone networks that provide plain old telephone service (POTS). The Internet 110 may include a global system of interconnected computer networks and devices that use common communication protocols, such as the transmission control protocol (TCP), user datagram protocol (UDP) and/or the internet protocol (IP) in the TCP/IP internet protocol suite. The networks 112 may include wired and/or wireless communications networks owned and/or operated by other service providers. For example, the networks 112 may include another CN connected to one or more RANs, which may employ the same RAT as the RAN 104/113 or a different RAT. [0043] Some or all of the WTRUs 102a, 102b, 102c, 102d in the communications system 100 may include multi-mode capabilities (e.g., the WTRUs 102a, 102b, 102c, 102d may include multiple transceivers for communicating with different wireless networks over different wireless links). For example, the WTRU 102c shown in FIG.1A may be configured to communicate with the base station 114a, which may employ a cellular-based radio technology, and with the base station 114b, which may employ an IEEE 802 radio technology. [0044] FIG.1B is a system diagram illustrating an example WTRU 102. As shown in FIG.1B, the WTRU 102 may include a processor 118, a transceiver 120, a transmit/receive element 122, a speaker/microphone 124, a keypad 126, a display/touchpad 128, non-removable memory 130, removable memory 132, a power source 134, a global positioning system (GPS) chipset 136, and/or other peripherals 138, among others. It will be appreciated that the WTRU 102 may include any sub-combination of the foregoing elements while remaining consistent with an embodiment. [0045] The processor 118 may be a general purpose processor, a special purpose processor, a conventional processor, a digital signal processor (DSP), a plurality of microprocessors, one or more microprocessors in association with a DSP core, a controller, a microcontroller, Application Specific
IDVC_ 2023P00519WO PATENT Integrated Circuits (ASICs), Field Programmable Gate Arrays (FPGAs) circuits, any other type of integrated circuit (IC), a state machine, and the like. The processor 118 may perform signal coding, data processing, power control, input/output processing, and/or any other functionality that enables the WTRU 102 to operate in a wireless environment. The processor 118 may be coupled to the transceiver 120, which may be coupled to the transmit/receive element 122. While FIG.1B depicts the processor 118 and the transceiver 120 as separate components, it will be appreciated that the processor 118 and the transceiver 120 may be integrated together in an electronic package or chip. [0046] The transmit/receive element 122 may be configured to transmit signals to, or receive signals from, a base station (e.g., the base station 114a) over the air interface 116. For example, in one embodiment, the transmit/receive element 122 may be an antenna configured to transmit and/or receive RF signals. In an embodiment, the transmit/receive element 122 may be an emitter/detector configured to transmit and/or receive IR, UV, or visible light signals, for example. In yet another embodiment, the transmit/receive element 122 may be configured to transmit and/or receive both RF and light signals. It will be appreciated that the transmit/receive element 122 may be configured to transmit and/or receive any combination of wireless signals. [0047] Although the transmit/receive element 122 is depicted in FIG.1B as a single element, the WTRU 102 may include any number of transmit/receive elements 122. More specifically, the WTRU 102 may employ MIMO technology. Thus, in one embodiment, the WTRU 102 may include two or more transmit/receive elements 122 (e.g., multiple antennas) for transmitting and receiving wireless signals over the air interface 116. [0048] The transceiver 120 may be configured to modulate the signals that are to be transmitted by the transmit/receive element 122 and to demodulate the signals that are received by the transmit/receive element 122. As noted above, the WTRU 102 may have multi-mode capabilities. Thus, the transceiver 120 may include multiple transceivers for enabling the WTRU 102 to communicate via multiple RATs, such as NR and IEEE 802.11, for example. [0049] The processor 118 of the WTRU 102 may be coupled to, and may receive user input data from, the speaker/microphone 124, the keypad 126, and/or the display/touchpad 128 (e.g., a liquid crystal display (LCD) display unit or organic light-emitting diode (OLED) display unit). The processor 118 may also output user data to the speaker/microphone 124, the keypad 126, and/or the display/touchpad 128. In addition, the processor 118 may access information from, and store data in, any type of suitable memory, such as the non-removable memory 130 and/or the removable memory 132. The non-removable memory 130 may include random-access memory (RAM), read-only memory (ROM), a hard disk, or any other type of memory storage device. The removable memory 132 may include a subscriber identity module (SIM) card, a memory stick, a secure digital (SD) memory card, and the like. In other embodiments, the processor 118
IDVC_ 2023P00519WO PATENT may access information from, and store data in, memory that is not physically located on the WTRU 102, such as on a server or a home computer (not shown). [0050] The processor 118 may receive power from the power source 134, and may be configured to distribute and/or control the power to the other components in the WTRU 102. The power source 134 may be any suitable device for powering the WTRU 102. For example, the power source 134 may include one or more dry cell batteries (e.g., nickel-cadmium (NiCd), nickel-zinc (NiZn), nickel metal hydride (NiMH), lithium-ion (Li-ion), etc.), solar cells, fuel cells, and the like. [0051] The processor 118 may also be coupled to the GPS chipset 136, which may be configured to provide location information (e.g., longitude and latitude) regarding the current location of the WTRU 102. In addition to, or in lieu of, the information from the GPS chipset 136, the WTRU 102 may receive location information over the air interface 116 from a base station (e.g., base stations 114a, 114b) and/or determine its location based on the timing of the signals being received from two or more nearby base stations. It will be appreciated that the WTRU 102 may acquire location information by way of any suitable location- determination method while remaining consistent with an embodiment. [0052] The processor 118 may further be coupled to other peripherals 138, which may include one or more software and/or hardware modules that provide additional features, functionality and/or wired or wireless connectivity. For example, the peripherals 138 may include an accelerometer, an e-compass, a satellite transceiver, a digital camera (for photographs and/or video), a universal serial bus (USB) port, a vibration device, a television transceiver, a hands free headset, a Bluetooth® module, a frequency modulated (FM) radio unit, a digital music player, a media player, a video game player module, an Internet browser, a Virtual Reality and/or Augmented Reality (VR/AR) device, an activity tracker, and the like. The peripherals 138 may include one or more sensors, the sensors may be one or more of a gyroscope, an accelerometer, a hall effect sensor, a magnetometer, an orientation sensor, a proximity sensor, a temperature sensor, a time sensor; a geolocation sensor; an altimeter, a light sensor, a touch sensor, a magnetometer, a barometer, a gesture sensor, a biometric sensor, and/or a humidity sensor. [0053] The WTRU 102 may include a full duplex radio for which transmission and reception of some or all of the signals (e.g., associated with particular subframes for both the UL (e.g., for transmission) and downlink (e.g., for reception) may be concurrent and/or simultaneous. The full duplex radio may include an interference management unit to reduce and or substantially eliminate self-interference via either hardware (e.g., a choke) or signal processing via a processor (e.g., a separate processor (not shown) or via processor 118). In an embodiment, the WRTU 102 may include a half-duplex radio for which transmission and reception of some or all of the signals (e.g., associated with particular subframes for either the UL (e.g., for transmission) or the downlink (e.g., for reception)).
IDVC_ 2023P00519WO PATENT [0054] FIG.1C is a system diagram illustrating the RAN 104 and the CN 106 according to an embodiment. As noted above, the RAN 104 may employ an E-UTRA radio technology to communicate with the WTRUs 102a, 102b, 102c over the air interface 116. The RAN 104 may also be in communication with the CN 106. [0055] The RAN 104 may include eNode-Bs 160a, 160b, 160c, though it will be appreciated that the RAN 104 may include any number of eNode-Bs while remaining consistent with an embodiment. The eNode-Bs 160a, 160b, 160c may each include one or more transceivers for communicating with the WTRUs 102a, 102b, 102c over the air interface 116. In one embodiment, the eNode-Bs 160a, 160b, 160c may implement MIMO technology. Thus, the eNode-B 160a, for example, may use multiple antennas to transmit wireless signals to, and/or receive wireless signals from, the WTRU 102a. [0056] Each of the eNode-Bs 160a, 160b, 160c may be associated with a particular cell (not shown) and may be configured to handle radio resource management decisions, handover decisions, scheduling of users in the UL and/or DL, and the like. As shown in FIG.1C, the eNode-Bs 160a, 160b, 160c may communicate with one another over an X2 interface. [0057] The CN 106 shown in FIG.1C may include a mobility management entity (MME) 162, a serving gateway (SGW) 164, and a packet data network (PDN) gateway (or PGW) 166. While each of the foregoing elements are depicted as part of the CN 106, it will be appreciated that any of these elements may be owned and/or operated by an entity other than the CN operator. [0058] The MME 162 may be connected to each of the eNode-Bs 162a, 162b, 162c in the RAN 104 via an S1 interface and may serve as a control node. For example, the MME 162 may be responsible for authenticating users of the WTRUs 102a, 102b, 102c, bearer activation/deactivation, selecting a particular serving gateway during an initial attach of the WTRUs 102a, 102b, 102c, and the like. The MME 162 may provide a control plane function for switching between the RAN 104 and other RANs (not shown) that employ other radio technologies, such as GSM and/or WCDMA. [0059] The SGW 164 may be connected to each of the eNode Bs 160a, 160b, 160c in the RAN 104 via the S1 interface. The SGW 164 may generally route and forward user data packets to/from the WTRUs 102a, 102b, 102c. The SGW 164 may perform other functions, such as anchoring user planes during inter- eNode B handovers, triggering paging when DL data is available for the WTRUs 102a, 102b, 102c, managing and storing contexts of the WTRUs 102a, 102b, 102c, and the like. [0060] The SGW 164 may be connected to the PGW 166, which may provide the WTRUs 102a, 102b, 102c with access to packet-switched networks, such as the Internet 110, to facilitate communications between the WTRUs 102a, 102b, 102c and IP-enabled devices.
IDVC_ 2023P00519WO PATENT [0061] The CN 106 may facilitate communications with other networks. For example, the CN 106 may provide the WTRUs 102a, 102b, 102c with access to circuit-switched networks, such as the PSTN 108, to facilitate communications between the WTRUs 102a, 102b, 102c and traditional land-line communications devices. For example, the CN 106 may include, or may communicate with, an IP gateway (e.g., an IP multimedia subsystem (IMS) server) that serves as an interface between the CN 106 and the PSTN 108. In addition, the CN 106 may provide the WTRUs 102a, 102b, 102c with access to the other networks 112, which may include other wired and/or wireless networks that are owned and/or operated by other service providers. [0062] Although the WTRU is described in FIGS.1A-1D as a wireless terminal, it is contemplated that in certain representative embodiments that such a terminal may use (e.g., temporarily or permanently) wired communication interfaces with the communication network. [0063] In representative embodiments, the other network 112 may be a WLAN. [0064] A WLAN in Infrastructure Basic Service Set (BSS) mode may have an Access Point (AP) for the BSS and one or more stations (STAs) associated with the AP. The AP may have an access or an interface to a Distribution System (DS) or another type of wired/wireless network that carries traffic in to and/or out of the BSS. Traffic to STAs that originates from outside the BSS may arrive through the AP and may be delivered to the STAs. Traffic originating from STAs to destinations outside the BSS may be sent to the AP to be delivered to respective destinations. Traffic between STAs within the BSS may be sent through the AP, for example, where the source STA may send traffic to the AP and the AP may deliver the traffic to the destination STA. The traffic between STAs within a BSS may be considered and/or referred to as peer-to- peer traffic. The peer-to-peer traffic may be sent between (e.g., directly between) the source and destination STAs with a direct link setup (DLS). In certain representative embodiments, the DLS may use an 802.11e DLS or an 802.11z tunneled DLS (TDLS). A WLAN using an Independent BSS (IBSS) mode may not have an AP, and the STAs (e.g., all of the STAs) within or using the IBSS may communicate directly with each other. The IBSS mode of communication may sometimes be referred to herein as an “ad- hoc” mode of communication. [0065] When using the 802.11ac infrastructure mode of operation or a similar mode of operations, the AP may transmit a beacon on a fixed channel, such as a primary channel. The primary channel may be a fixed width (e.g., 20 MHz wide bandwidth) or a dynamically set width via signaling. The primary channel may be the operating channel of the BSS and may be used by the STAs to establish a connection with the AP. In certain representative embodiments, Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA) may be implemented, for example in in 802.11 systems. For CSMA/CA, the STAs (e.g., every STA), including the AP, may sense the primary channel. If the primary channel is sensed/detected and/or
IDVC_ 2023P00519WO PATENT determined to be busy by a particular STA, the particular STA may back off. One STA (e.g., only one station) may transmit at any given time in a given BSS. [0066] High Throughput (HT) STAs may use a 40 MHz wide channel for communication, for example, via a combination of the primary 20 MHz channel with an adjacent or nonadjacent 20 MHz channel to form a 40 MHz wide channel. [0067] Very High Throughput (VHT) STAs may support 20MHz, 40 MHz, 80 MHz, and/or 160 MHz wide channels. The 40 MHz, and/or 80 MHz, channels may be formed by combining contiguous 20 MHz channels. A 160 MHz channel may be formed by combining 8 contiguous 20 MHz channels, or by combining two non-contiguous 80 MHz channels, which may be referred to as an 80+80 configuration. For the 80+80 configuration, the data, after channel encoding, may be passed through a segment parser that may divide the data into two streams. Inverse Fast Fourier Transform (IFFT) processing, and time domain processing, may be done on each stream separately. The streams may be mapped on to the two 80 MHz channels, and the data may be transmitted by a transmitting STA. At the receiver of the receiving STA, the above described operation for the 80+80 configuration may be reversed, and the combined data may be sent to the Medium Access Control (MAC). [0068] Sub 1 GHz modes of operation are supported by 802.11af and 802.11ah. The channel operating bandwidths, and carriers, are reduced in 802.11af and 802.11ah relative to those used in 802.11n, and 802.11ac.802.11af supports 5 MHz, 10 MHz and 20 MHz bandwidths in the TV White Space (TVWS) spectrum, and 802.11ah supports 1 MHz, 2 MHz, 4 MHz, 8 MHz, and 16 MHz bandwidths using non- TVWS spectrum. According to a representative embodiment, 802.11ah may support Meter Type Control/Machine-Type Communications, such as MTC devices in a macro coverage area. MTC devices may have certain capabilities, for example, limited capabilities including support for (e.g., only support for) certain and/or limited bandwidths. The MTC devices may include a battery with a battery life above a threshold (e.g., to maintain a very long battery life). [0069] WLAN systems, which may support multiple channels, and channel bandwidths, such as 802.11n, 802.11ac, 802.11af, and 802.11ah, include a channel which may be designated as the primary channel. The primary channel may have a bandwidth equal to the largest common operating bandwidth supported by all STAs in the BSS. The bandwidth of the primary channel may be set and/or limited by a STA, from among all STAs in operating in a BSS, which supports the smallest bandwidth operating mode. In the example of 802.11ah, the primary channel may be 1 MHz wide for STAs (e.g., MTC type devices) that support (e.g., only support) a 1 MHz mode, even if the AP, and other STAs in the BSS support 2 MHz, 4 MHz, 8 MHz, 16 MHz, and/or other channel bandwidth operating modes. Carrier sensing and/or Network Allocation Vector (NAV) settings may depend on the status of the primary channel. If the primary channel is busy, for example, due to a STA (which supports only a 1 MHz operating mode), transmitting to the AP, the
IDVC_ 2023P00519WO PATENT entire available frequency bands may be considered busy even though a majority of the frequency bands remains idle and may be available. [0070] In the United States, the available frequency bands, which may be used by 802.11ah, are from 902 MHz to 928 MHz. In Korea, the available frequency bands are from 917.5 MHz to 923.5 MHz. In Japan, the available frequency bands are from 916.5 MHz to 927.5 MHz. The total bandwidth available for 802.11ah is 6 MHz to 26 MHz depending on the country code. [0071] FIG.1D is a system diagram illustrating the RAN 113 and the CN 115 according to an embodiment. As noted above, the RAN 113 may employ an NR radio technology to communicate with the WTRUs 102a, 102b, 102c over the air interface 116. The RAN 113 may also be in communication with the CN 115. [0072] The RAN 113 may include gNBs 180a, 180b, 180c, though it will be appreciated that the RAN 113 may include any number of gNBs while remaining consistent with an embodiment. The gNBs 180a, 180b, 180c may each include one or more transceivers for communicating with the WTRUs 102a, 102b, 102c over the air interface 116. In one embodiment, the gNBs 180a, 180b, 180c may implement MIMO technology. For example, gNBs 180a, 108b may utilize beamforming to transmit signals to and/or receive signals from the gNBs 180a, 180b, 180c. Thus, the gNB 180a, for example, may use multiple antennas to transmit wireless signals to, and/or receive wireless signals from, the WTRU 102a. In an embodiment, the gNBs 180a, 180b, 180c may implement carrier aggregation technology. For example, the gNB 180a may transmit multiple component carriers to the WTRU 102a (not shown). A subset of these component carriers may be on unlicensed spectrum while the remaining component carriers may be on licensed spectrum. In an embodiment, the gNBs 180a, 180b, 180c may implement Coordinated Multi-Point (CoMP) technology. For example, WTRU 102a may receive coordinated transmissions from gNB 180a and gNB 180b (and/or gNB 180c). [0073] The WTRUs 102a, 102b, 102c may communicate with gNBs 180a, 180b, 180c using transmissions associated with a scalable numerology. For example, the OFDM symbol spacing and/or OFDM subcarrier spacing may vary for different transmissions, different cells, and/or different portions of the wireless transmission spectrum. The WTRUs 102a, 102b, 102c may communicate with gNBs 180a, 180b, 180c using subframe or transmission time intervals (TTIs) of various or scalable lengths (e.g., containing varying number of OFDM symbols and/or lasting varying lengths of absolute time). [0074] The gNBs 180a, 180b, 180c may be configured to communicate with the WTRUs 102a, 102b, 102c in a standalone configuration and/or a non-standalone configuration. In the standalone configuration, WTRUs 102a, 102b, 102c may communicate with gNBs 180a, 180b, 180c without also accessing other RANs (e.g., such as eNode-Bs 160a, 160b, 160c). In the standalone configuration, WTRUs 102a, 102b, 102c may utilize one or more of gNBs 180a, 180b, 180c as a mobility anchor point. In the standalone
IDVC_ 2023P00519WO PATENT configuration, WTRUs 102a, 102b, 102c may communicate with gNBs 180a, 180b, 180c using signals in an unlicensed band. In a non-standalone configuration WTRUs 102a, 102b, 102c may communicate with/connect to gNBs 180a, 180b, 180c while also communicating with/connecting to another RAN such as eNode-Bs 160a, 160b, 160c. For example, WTRUs 102a, 102b, 102c may implement DC principles to communicate with one or more gNBs 180a, 180b, 180c and one or more eNode-Bs 160a, 160b, 160c substantially simultaneously. In the non-standalone configuration, eNode-Bs 160a, 160b, 160c may serve as a mobility anchor for WTRUs 102a, 102b, 102c and gNBs 180a, 180b, 180c may provide additional coverage and/or throughput for servicing WTRUs 102a, 102b, 102c. [0075] Each of the gNBs 180a, 180b, 180c may be associated with a particular cell (not shown) and may be configured to handle radio resource management decisions, handover decisions, scheduling of users in the UL and/or DL, support of network slicing, dual connectivity, interworking between NR and E- UTRA, routing of user plane data towards User Plane Function (UPF) 184a, 184b, routing of control plane information towards Access and Mobility Management Function (AMF) 182a, 182b and the like. As shown in FIG.1D, the gNBs 180a, 180b, 180c may communicate with one another over an Xn interface. [0076] The CN 115 shown in FIG.1D may include at least one AMF 182a, 182b, at least one UPF 184a,184b, at least one Session Management Function (SMF) 183a, 183b, and possibly a Data Network (DN) 185a, 185b. While each of the foregoing elements are depicted as part of the CN 115, it will be appreciated that any of these elements may be owned and/or operated by an entity other than the CN operator. [0077] The AMF 182a, 182b may be connected to one or more of the gNBs 180a, 180b, 180c in the RAN 113 via an N2 interface and may serve as a control node. For example, the AMF 182a, 182b may be responsible for authenticating users of the WTRUs 102a, 102b, 102c, support for network slicing (e.g., handling of different PDU sessions with different requirements), selecting a particular SMF 183a, 183b, management of the registration area, termination of NAS signaling, mobility management, and the like. Network slicing may be used by the AMF 182a, 182b in order to customize CN support for WTRUs 102a, 102b, 102c based on the types of services being utilized WTRUs 102a, 102b, 102c. For example, different network slices may be established for different use cases such as services relying on ultra-reliable low latency (URLLC) access, services relying on enhanced massive mobile broadband (eMBB) access, services for machine type communication (MTC) access, and/or the like. The AMF 162 may provide a control plane function for switching between the RAN 113 and other RANs (not shown) that employ other radio technologies, such as LTE, LTE-A, LTE-A Pro, and/or non-3GPP access technologies such as WiFi. [0078] The SMF 183a, 183b may be connected to an AMF 182a, 182b in the CN 115 via an N11 interface. The SMF 183a, 183b may also be connected to a UPF 184a, 184b in the CN 115 via an N4 interface. The SMF 183a, 183b may select and control the UPF 184a, 184b and configure the routing of
IDVC_ 2023P00519WO PATENT traffic through the UPF 184a, 184b. The SMF 183a, 183b may perform other functions, such as managing and allocating UE IP address, managing PDU sessions, controlling policy enforcement and QoS, providing downlink data notifications, and the like. A PDU session type may be IP-based, non-IP based, Ethernet- based, and the like. [0079] The UPF 184a, 184b may be connected to one or more of the gNBs 180a, 180b, 180c in the RAN 113 via an N3 interface, which may provide the WTRUs 102a, 102b, 102c with access to packet- switched networks, such as the Internet 110, to facilitate communications between the WTRUs 102a, 102b, 102c and IP-enabled devices. The UPF 184, 184b may perform other functions, such as routing and forwarding packets, enforcing user plane policies, supporting multi-homed PDU sessions, handling user plane QoS, buffering downlink packets, providing mobility anchoring, and the like. [0080] The CN 115 may facilitate communications with other networks. For example, the CN 115 may include, or may communicate with, an IP gateway (e.g., an IP multimedia subsystem (IMS) server) that serves as an interface between the CN 115 and the PSTN 108. In addition, the CN 115 may provide the WTRUs 102a, 102b, 102c with access to the other networks 112, which may include other wired and/or wireless networks that are owned and/or operated by other service providers. In one embodiment, the WTRUs 102a, 102b, 102c may be connected to a local Data Network (DN) 185a, 185b through the UPF 184a, 184b via the N3 interface to the UPF 184a, 184b and an N6 interface between the UPF 184a, 184b and the DN 185a, 185b. [0081] In view of Figures 1A-1D, and the corresponding description of Figures 1A-1D, one or more, or all, of the functions described herein with regard to one or more of: WTRU 102a-d, Base Station 114a-b, eNode-B 160a-c, MME 162, SGW 164, PGW 166, gNB 180a-c, AMF 182a-b, UPF 184a-b, SMF 183a-b, DN 185a-b, and/or any other device(s) described herein, may be performed by one or more emulation devices (not shown). The emulation devices may be one or more devices configured to emulate one or more, or all, of the functions described herein. For example, the emulation devices may be used to test other devices and/or to simulate network and/or WTRU functions. [0082] The emulation devices may be designed to implement one or more tests of other devices in a lab environment and/or in an operator network environment. For example, the one or more emulation devices may perform the one or more, or all, functions while being fully or partially implemented and/or deployed as part of a wired and/or wireless communication network in order to test other devices within the communication network. The one or more emulation devices may perform the one or more, or all, functions while being temporarily implemented/deployed as part of a wired and/or wireless communication network. The emulation device may be directly coupled to another device for purposes of testing and/or may performing testing using over-the-air wireless communications.
IDVC_ 2023P00519WO PATENT [0083] The one or more emulation devices may perform the one or more, including all, functions while not being implemented/deployed as part of a wired and/or wireless communication network. For example, the emulation devices may be utilized in a testing scenario in a testing laboratory and/or a non-deployed (e.g., testing) wired and/or wireless communication network in order to implement testing of one or more components. The one or more emulation devices may be test equipment. Direct RF coupling and/or wireless communications via RF circuitry (e.g., which may include one or more antennas) may be used by the emulation devices to transmit and/or receive data. [0084] This application describes a variety of aspects, including tools, features, examples, models, approaches, etc. Many of these aspects are described with specificity and, at least to show the individual characteristics, are often described in a manner that may sound limiting. However, this is for purposes of clarity in description, and does not limit the application or scope of those aspects. Indeed, all of the different aspects may be combined and interchanged to provide further aspects. Moreover, the aspects may be combined and interchanged with aspects described in earlier filings as well. [0085] The aspects described and contemplated in this application may be implemented in many different forms. FIGS.5-11 described herein may provide some examples, but other examples are contemplated. The discussion of FIGS.5-11 does not limit the breadth of the implementations. At least one of the aspects generally relates to video encoding and decoding, and at least one other aspect generally relates to transmitting a bitstream generated or encoded. These and other aspects may be implemented as a method, an apparatus, a computer readable storage medium having stored thereon instructions for encoding or decoding video data according to any of the methods described, and/or a computer readable storage medium having stored thereon a bitstream generated according to any of the methods described. [0086] In the present application, the terms “reconstructed” and “decoded” may be used interchangeably, the terms “pixel” and “sample” may be used interchangeably, the terms “image,” “picture” and “frame” may be used interchangeably. [0087] Various methods are described herein, and each of the methods comprises one or more steps or actions for achieving the described method. Unless a specific order of steps or actions is required for proper operation of the method, the order and/or use of specific steps and/or actions may be modified or combined. Additionally, terms such as “first”, “second”, etc. may be used in various examples to modify an element, component, step, operation, etc., such as, for example, a “first decoding” and a “second decoding”. Use of such terms does not imply an ordering to the modified operations unless specifically required. So, in this example, the first decoding need not be performed before the second decoding, and may occur, for example, before, during, or in an overlapping time period with the second decoding.
IDVC_ 2023P00519WO PATENT [0088] Various methods and other aspects described in this application may be used to modify modules, for example, decoding modules, of a video encoder 200 and decoder 300 as shown in FIG.2 and FIG.3. Moreover, the subject matter disclosed herein may be applied, for example, to any type, format or version of video coding, whether described in a standard or a recommendation, whether pre-existing or future- developed, and extensions of any such standards and recommendations. Unless indicated otherwise, or technically precluded, the aspects described in this application may be used individually or in combination. [0089] Various numeric values are used in examples described the present application, such as the number of luma samples, block sizes, number of table entries, number of merge candidates, number of selected candidates, resolutions, distances, refinement positions, number of regions, region sizes, number of blocks, threshold values, weight values, number of filter taps, bias values, number of bits, number of BVs, equation/algorithm multiplication values, division values, and constants, number of modes, etc. These and other specific values are for purposes of describing examples and the aspects described are not limited to these specific values. [0090] FIG.2 is a diagram showing an example video encoder. Variations of example encoder 200 are contemplated, but the encoder 200 is described below for purposes of clarity without describing all expected variations. [0091] Before being encoded, the video sequence may go through pre-encoding processing (201), for example, applying a color transform to the input color picture (e.g., conversion from RGB 4:4:4 to YCbCr 4:2:0), or performing a remapping of the input picture components in order to get a signal distribution more resilient to compression (for instance using a histogram equalization of one of the color components). Metadata may be associated with the pre-processing, and attached to the bitstream. [0092] In the encoder 200, a picture is encoded by the encoder elements as described below. The picture to be encoded is partitioned (202) and processed in units of, for example, coding units (CUs). Each unit is encoded using, for example, either an intra or inter mode. When a unit is encoded in an intra mode, it performs intra prediction (260). In an inter mode, motion estimation (275) and compensation (270) are performed. The encoder decides (205) which one of the intra mode or inter mode to use for encoding the unit, and indicates the intra/inter decision by, for example, a prediction mode flag. Prediction residuals are calculated, for example, by subtracting (210) the predicted block from the original image block. [0093] The prediction residuals are then transformed (225) and quantized (230). The quantized transform coefficients, as well as motion vectors and other syntax elements, such as picture partitioning information, are entropy coded (245) to output a bitstream. The encoder can skip the transform and apply quantization directly to the non-transformed residual signal. The encoder can bypass both transform and quantization, i.e., the residual is coded directly without the application of the transform or quantization processes.
IDVC_ 2023P00519WO PATENT [0094] The encoder decodes an encoded block to provide a reference for further predictions. The quantized transform coefficients are de-quantized (240) and inverse transformed (250) to decode prediction residuals. Combining (255) the decoded prediction residuals and the predicted block, an image block is reconstructed. In-loop filters (265) are applied to the reconstructed picture to perform, for example, deblocking/SAO (Sample Adaptive Offset)/ALF (Adaptive Loop Filtering) filtering to reduce encoding artifacts. The filtered image is stored at a reference picture buffer (280). [0095] FIG.3 is a diagram showing an example of a video decoder. In example decoder 300, a bitstream is decoded by the decoder elements as described below. Video decoder 300 generally performs a decoding pass reciprocal to the encoding pass as described in FIG.2. The encoder 200 also generally performs video decoding as part of encoding video data. [0096] In particular, the input of the decoder includes a video bitstream, which may be generated by video encoder 200. The bitstream is first entropy decoded (330) to obtain transform coefficients, prediction modes, motion vectors, and other coded information. The picture partition information indicates how the picture is partitioned. The decoder may therefore divide (335) the picture according to the decoded picture partitioning information. The transform coefficients are de-quantized (340) and inverse transformed (350) to decode the prediction residuals. Combining (355) the decoded prediction residuals and the predicted block, an image block is reconstructed. The predicted block may be obtained (370) from intra prediction (360) or motion-compensated prediction (i.e., inter prediction) (375). In-loop filters (365) are applied to the reconstructed image. The filtered image is stored at a reference picture buffer (380). In some examples (e.g., for a given picture) the contents of the reference picture buffer 380 on the decoder 300 side may be identical to the contents of the reference picture buffer 280 on the encoder 200 side (e.g., for the same picture). [0097] The decoded picture can further go through post-decoding processing (385), for example, an inverse color transform (e.g. conversion from YCbCr 4:2:0 to RGB 4:4:4) or an inverse remapping performing the inverse of the remapping process performed in the pre-encoding processing (201). The post-decoding processing can use metadata derived in the pre-encoding processing and signaled in the bitstream. In an example, the decoded images (e.g., after application of the in-loop filters (365) and/or after post-decoding processing (385), if post-decoding processing is used) may be sent to a display device for rendering to a user. [0098] FIG.4 is a diagram showing an example of a system in which various aspects and examples described herein may be implemented. System 400 may be embodied as a device including the various components described below and is configured to perform one or more of the aspects described in this document. Examples of such devices, include, but are not limited to, various electronic devices such as personal computers, laptop computers, smartphones, tablet computers, digital multimedia set top boxes,
IDVC_ 2023P00519WO PATENT digital television receivers, personal video recording systems, connected home appliances, and servers. Elements of system 400, singly or in combination, may be embodied in a single integrated circuit (IC), multiple ICs, and/or discrete components. For example, in at least one example, the processing and encoder/decoder elements of system 400 are distributed across multiple ICs and/or discrete components. In various examples, the system 400 is communicatively coupled to one or more other systems, or other electronic devices, via, for example, a communications bus or through dedicated input and/or output ports. In various examples, the system 400 is configured to implement one or more of the aspects described in this document. [0099] The system 400 includes at least one processor 410 configured to execute instructions loaded therein for implementing, for example, the various aspects described in this document. Processor 410 can include embedded memory, input output interface, and various other circuitries as known in the art. The system 400 includes at least one memory 420 (e.g., a volatile memory device, and/or a non-volatile memory device). System 400 includes a storage device 440, which can include non-volatile memory and/or volatile memory, including, but not limited to, Electrically Erasable Programmable Read-Only Memory (EEPROM), Read-Only Memory (ROM), Programmable Read-Only Memory (PROM), Random Access Memory (RAM), Dynamic Random Access Memory (DRAM), Static Random Access Memory (SRAM), flash, magnetic disk drive, and/or optical disk drive. The storage device 440 can include an internal storage device, an attached storage device (including detachable and non-detachable storage devices), and/or a network accessible storage device, as non-limiting examples. [0100] System 400 includes an encoder/decoder module 430 configured, for example, to process data to provide an encoded video or decoded video, and the encoder/decoder module 430 can include its own processor and memory. The encoder/decoder module 430 represents module(s) that may be included in a device to perform the encoding and/or decoding functions. As is known, a device can include one or both of the encoding and decoding modules. Additionally, encoder/decoder module 430 may be implemented as a separate element of system 400 or may be incorporated within processor 410 as a combination of hardware and software as known to those skilled in the art. [0101] Program code to be loaded onto processor 410 or encoder/decoder 430 to perform the various aspects described in this document may be stored in storage device 440 and subsequently loaded onto memory 420 for execution by processor 410. In accordance with various examples, one or more of processor 410, memory 420, storage device 440, and encoder/decoder module 430 can store one or more of various items during the performance of the processes described in this document. Such stored items can include, but are not limited to, the input video, the decoded video or portions of the decoded video, the bitstream, matrices, variables, and intermediate or final results from the processing of equations, formulas, operations, and operational logic.
IDVC_ 2023P00519WO PATENT [0102] In some examples, memory inside of the processor 410 and/or the encoder/decoder module 430 is used to store instructions and to provide working memory for processing that is needed during encoding or decoding. In other examples, however, a memory external to the processing device (for example, the processing device may be either the processor 410 or the encoder/decoder module 430) is used for one or more of these functions. The external memory may be the memory 420 and/or the storage device 440, for example, a dynamic volatile memory and/or a non-volatile flash memory. In several examples, an external non-volatile flash memory is used to store the operating system of, for example, a television. In at least one example, a fast external dynamic volatile memory such as a RAM is used as working memory for video encoding and decoding operations. [0103] The input to the elements of system 400 may be provided through various input devices as indicated in block 445. Such input devices include, but are not limited to, (i) a radio frequency (RF) portion that receives an RF signal transmitted, for example, over the air by a broadcaster, (ii) a Component (COMP) input terminal (or a set of COMP input terminals), (iii) a Universal Serial Bus (USB) input terminal, and/or (iv) a High Definition Multimedia Interface (HDMI) input terminal. Other examples, not shown in FIG. 4, include composite video. [0104] In various examples, the input devices of block 445 have associated respective input processing elements as known in the art. For example, the RF portion may be associated with elements suitable for (i) selecting a desired frequency (also referred to as selecting a signal, or band-limiting a signal to a band of frequencies), (ii) downconverting the selected signal, (iii) band-limiting again to a narrower band of frequencies to select (for example) a signal frequency band which may be referred to as a channel in certain examples, (iv) demodulating the downconverted and band-limited signal, (v) performing error correction, and/or (vi) demultiplexing to select the desired stream of data packets. The RF portion of various examples includes one or more elements to perform these functions, for example, frequency selectors, signal selectors, band-limiters, channel selectors, filters, downconverters, demodulators, error correctors, and demultiplexers. The RF portion can include a tuner that performs various of these functions, including, for example, downconverting the received signal to a lower frequency (for example, an intermediate frequency or a near-baseband frequency) or to baseband. In one set-top box example, the RF portion and its associated input processing element receives an RF signal transmitted over a wired (for example, cable) medium, and performs frequency selection by filtering, downconverting, and filtering again to a desired frequency band. Various examples rearrange the order of the above-described (and other) elements, remove some of these elements, and/or add other elements performing similar or different functions. Adding elements can include inserting elements in between existing elements, such as, for example, inserting amplifiers and an analog-to-digital converter. In various examples, the RF portion includes an antenna.
IDVC_ 2023P00519WO PATENT [0105] The USB and/or HDMI terminals can include respective interface processors for connecting system 400 to other electronic devices across USB and/or HDMI connections. It is to be understood that various aspects of input processing, for example, Reed-Solomon error correction, may be implemented, for example, within a separate input processing IC or within processor 410 as necessary. Similarly, aspects of USB or HDMI interface processing may be implemented within separate interface ICs or within processor 410 as necessary. The demodulated, error corrected, and demultiplexed stream is provided to various processing elements, including, for example, processor 410, and encoder/decoder 430 operating in combination with the memory and storage elements to process the datastream as necessary for presentation on an output device. [0106] Various elements of system 400 may be provided within an integrated housing, Within the integrated housing, the various elements may be interconnected and transmit data therebetween using suitable connection arrangement 425, for example, an internal bus as known in the art, including the Inter- IC (I2C) bus, wiring, and printed circuit boards. [0107] The system 400 includes communication interface 450 that enables communication with other devices via communication channel 460. The communication interface 450 can include, but is not limited to, a transceiver configured to transmit and to receive data over communication channel 460. The communication interface 450 can include, but is not limited to, a modem or network card and the communication channel 460 may be implemented, for example, within a wired and/or a wireless medium. [0108] Data is streamed, or otherwise provided, to the system 400, in various examples, using a wireless network such as a Wi-Fi network, for example IEEE 802.11 (IEEE refers to the Institute of Electrical and Electronics Engineers). The Wi-Fi signal of these examples is received over the communications channel 460 and the communications interface 450 which are adapted for Wi-Fi communications. The communications channel 460 of these examples is typically connected to an access point or router that provides access to external networks including the Internet for allowing streaming applications and other over-the-top communications. Other examples provide streamed data to the system 400 using a set-top box that delivers the data over the HDMI connection of the input block 445. Still other examples provide streamed data to the system 400 using the RF connection of the input block 445. As indicated above, various examples provide data in a non-streaming manner. Additionally, various examples use wireless networks other than Wi-Fi, for example a cellular network or a Bluetooth® network. [0109] The system 400 can provide an output signal to various output devices, including a display 475, speakers 485, and other peripheral devices 495. The display 475 of various examples includes one or more of, for example, a touchscreen display, an organic light-emitting diode (OLED) display, a curved display, and/or a foldable display. The display 475 may be for a television, a tablet, a laptop, a cell phone (mobile phone), or other device. The display 475 can also be integrated with other components (for
IDVC_ 2023P00519WO PATENT example, as in a smart phone), or separate (for example, an external monitor for a laptop). The other peripheral devices 495 include, in various examples, one or more of a stand-alone digital video disc (or digital versatile disc) (DVD, for both terms), a disk player, a stereo system, and/or a lighting system. Various examples use one or more peripheral devices 495 that provide a function based on the output of the system 400. For example, a disk player performs the function of playing the output of the system 400. [0110] In various examples, control signals are communicated between the system 400 and the display 475, speakers 485, or other peripheral devices 495 using signaling such as AV.Link, Consumer Electronics Control (CEC), or other communications protocols that enable device-to-device control with or without user intervention. The output devices may be communicatively coupled to system 400 via dedicated connections through respective interfaces 470, 480, and 490. Alternatively, the output devices may be connected to system 400 using the communications channel 460 via the communications interface 450. The display 475 and speakers 485 may be integrated in a single unit with the other components of system 400 in an electronic device such as, for example, a television. In various examples, the display interface 470 includes a display driver, such as, for example, a timing controller (T Con) chip. [0111] The display 475 and speakers 485 can alternatively be separate from one or more of the other components, for example, if the RF portion of input 445 is part of a separate set-top box. In various examples in which the display 475 and speakers 485 are external components, the output signal may be provided via dedicated output connections, including, for example, HDMI ports, USB ports, or COMP outputs. [0112] The examples may be carried out by computer software implemented by the processor 410 or by hardware, or by a combination of hardware and software. As a non-limiting example, the examples may be implemented by one or more integrated circuits. The memory 420 may be of any type appropriate to the technical environment and may be implemented using any appropriate data storage technology, such as optical memory devices, magnetic memory devices, semiconductor-based memory devices, fixed memory, and removable memory, as non-limiting examples. The processor 410 may be of any type appropriate to the technical environment, and can encompass one or more of microprocessors, general purpose computers, special purpose computers, and processors based on a multi-core architecture, as non-limiting examples. [0113] Various implementations involve decoding. “Decoding”, as used in this application, can encompass all or part of the processes performed, for example, on a received encoded sequence in order to produce a final output suitable for display. In various examples, such processes include one or more of the processes typically performed by a decoder, for example, entropy decoding, inverse quantization, inverse transformation, and differential decoding. In various examples, such processes also, or alternatively, include processes performed by a decoder of various implementations described in this
IDVC_ 2023P00519WO PATENT application, for example, determining that bi-predictive local illumination compensation (LIC) is enabled for a current block; determining that the current block is coded using intra block copy (IBC) mode; obtaining a first LIC parameter based on a first block vector associated with the current block; obtaining a second LIC parameter based on a second block vector associated with the current block; decoding the current block based on the first and second LIC parameters; obtaining a first template of a first reference block based on the first block vector, wherein the first LIC parameter is derived based on a template of the current block and the first template of the first reference block; obtaining a second template of a second reference block based on the second block vector, wherein the second LIC parameter is derived based on the template of the current block and the second template of the second reference block; obtaining a first prediction block based on the first block vector; refining the first prediction block based on the first LIC parameter; obtaining a second prediction block based on the second block vector; refining the second prediction block based on the second LIC parameter; and predicting the current block based on the first refined prediction block and the second refined prediction block, etc. [0114] As further examples, in one example “decoding” refers only to entropy decoding, in another example “decoding” refers only to differential decoding, and in another example “decoding” refers to a combination of entropy decoding and differential decoding. Whether the phrase “decoding process” is intended to refer specifically to a subset of operations or generally to the broader decoding process will be clear based on the context of the specific descriptions and is believed to be well understood by those skilled in the art. [0115] Various implementations involve encoding. In an analogous way to the above discussion about “decoding”, “encoding” as used in this application can encompass all or part of the processes performed, for example, on an input video sequence in order to produce an encoded bitstream. In various examples, such processes include one or more of the processes typically performed by an encoder, for example, partitioning, differential encoding, transformation, quantization, and entropy encoding. In various examples, such processes also, or alternatively, include processes performed by an encoder of various implementations described in this application, for example, determining to enable bi-predictive local illumination compensation (LIC) for a current block; determining to code the current block using intra block copy (IBC) mode; obtaining a first LIC parameter based on a first block vector associated with the current block; obtaining a second LIC parameter based on a second block vector associated with the current block; encoding the current block based on the first and second LIC parameters; obtaining a first template of a first reference block based on the first block vector, wherein the first LIC parameter is derived based on a template of the current block and the first template of the first reference block; obtaining a second template of a second reference block based on the second block vector, wherein the second LIC parameter is derived based on the template of the current block and the second template of the second reference block;
IDVC_ 2023P00519WO PATENT obtaining a first prediction block based on the first block vector; refining the first prediction block based on the first LIC parameter; obtaining a second prediction block based on the second block vector; refining the second prediction block based on the second LIC parameter; generating a residual of the current block based on the first refined prediction block and the second refined prediction block; and including an indication of the residual in video data, etc. [0116] As further examples, in one example “encoding” refers only to entropy encoding, in another example “encoding” refers only to differential encoding, and in another example “encoding” refers to a combination of differential encoding and entropy encoding. Whether the phrase “encoding process” is intended to refer specifically to a subset of operations or generally to the broader encoding process will be clear based on the context of the specific descriptions and is believed to be well understood by those skilled in the art. [0117] Note that syntax elements as used herein, such as terms in equations and algorithms, signal (e.g., flag, mode) labels/names, etc., such as SearchRange_w, SearchRange_h, BlkW, BlkH, intra_tmp_idx, ^^^^ ^^^^ ^^^^ ^^^^, ^^^^ ^^^^ ^^^^ ^^^^ ^^^^ ^^^^ ^^^^, ^^^^1 ^^^^ ^^^^ ^^^^ ^^^^, ^^^^2 ^^^^ ^^^^ ^^^^ ^^^^ ^^^^ ^^^^, predLumaVal, and so on, are descriptive terms. As such, they do not preclude the use of other syntax element names. [0118] When a figure is presented as a flow diagram, it should be understood that it also provides a block diagram of a corresponding apparatus. Similarly, when a figure is presented as a block diagram, it should be understood that it also provides a flow diagram of a corresponding method/process. [0119] The implementations and aspects described herein may be implemented in, for example, a method or a process, an apparatus, a software program, a data stream, or a signal. Even if only discussed in the context of a single form of implementation (for example, discussed only as a method), the implementation of features discussed can also be implemented in other forms (for example, an apparatus or program). An apparatus may be implemented in, for example, appropriate hardware, software, and firmware. The methods may be implemented in, for example, a processor, which refers to processing devices in general, including, for example, a computer, a microprocessor, an integrated circuit, or a programmable logic device. Processors also include communication devices, such as, for example, computers, cell phones, portable/personal digital assistants ("PDAs"), and other devices that facilitate communication of information between end-users. [0120] Reference to “one example” or “an example” or “one implementation” or “an implementation”, as well as other variations thereof, means that a particular feature, structure, characteristic, and so forth described in connection with the example is included in at least one example. Thus, the appearances of the phrase “in one example” or “in an example” or “in one implementation” or “in an implementation”, as well any other variations, appearing in various places throughout this application are not necessarily all referring to the same example.
IDVC_ 2023P00519WO PATENT [0121] Additionally, this application may refer to “determining” various pieces of information. Determining the information can include one or more of, for example, estimating the information, calculating the information, predicting the information, or retrieving the information from memory. Obtaining may include receiving, retrieving, constructing, generating, and/or determining. [0122] Further, this application may refer to “accessing” various pieces of information. Accessing the information can include one or more of, for example, receiving the information, retrieving the information (for example, from memory), storing the information, moving the information, copying the information, calculating the information, determining the information, predicting the information, or estimating the information. [0123] Additionally, this application may refer to “receiving” various pieces of information. Receiving is, as with “accessing”, intended to be a broad term. Receiving the information can include one or more of, for example, accessing the information, or retrieving the information (for example, from memory). Further, “receiving” is typically involved, in one way or another, during operations such as, for example, storing the information, processing the information, transmitting the information, moving the information, copying the information, erasing the information, calculating the information, determining the information, predicting the information, or estimating the information. [0124] It is to be appreciated that the use of any of the following “/”, “and/or”, and “at least one of”, for example, in the cases of “A/B”, “A and/or B” and “at least one of A and B”, is intended to encompass the selection of the first listed option (A) only, or the selection of the second listed option (B) only, or the selection of both options (A and B). As a further example, in the cases of “A, B, and/or C” and “at least one of A, B, and C”, such phrasing is intended to encompass the selection of the first listed option (A) only, or the selection of the second listed option (B) only, or the selection of the third listed option (C) only, or the selection of the first and the second listed options (A and B) only, or the selection of the first and third listed options (A and C) only, or the selection of the second and third listed options (B and C) only, or the selection of all three options (A and B and C). This may be extended, as is clear to one of ordinary skill in this and related arts, for as many items as are listed. [0125] Also, as used herein, the word “signal” refers to, among other things, indicating something to a corresponding decoder. Encoder signals may include, for example, indications of (e.g., flags for) IBC-LIC modes (e.g., No IBC-LIC, Default IBC-LIC, Multi-models IBC-LIC, Top-only IBC-LIC, Left-only IBC-LIC), partial template mode, partial template area, bi-predictive IBC mode at CU level, LIC flag for CUs coded in IBC BVP-merge mode, usage of a bi-predictive LIC model for a CU predicted in bi-predictive IBC, etc. In this way, in an example the same parameter is used at both the encoder side and the decoder side. Thus, for example, an encoder can transmit (explicit signaling) a particular parameter to the decoder so that the decoder can use the same particular parameter. Conversely, if the decoder already has the particular
IDVC_ 2023P00519WO PATENT parameter as well as others, then signaling may be used without transmitting (implicit signaling) to simply allow the decoder to know and select the particular parameter. By avoiding transmission of any actual functions, a bit savings is realized in various examples. It is to be appreciated that signaling may be accomplished in a variety of ways. For example, one or more syntax elements, flags, and so forth are used to signal information to a corresponding decoder in various examples. While the preceding relates to the verb form of the word “signal”, the word “signal” can also be used herein as a noun. [0126] As will be evident to one of ordinary skill in the art, implementations may produce a variety of signals formatted to carry information that may be, for example, stored or transmitted. The information can include, for example, instructions for performing a method, or data produced by one of the described implementations. For example, a signal may be formatted to carry the bitstream of a described example. Such a signal may be formatted, for example, as an electromagnetic wave (for example, using a radio frequency portion of spectrum) or as a baseband signal. The formatting may include, for example, encoding a data stream and modulating a carrier with the encoded data stream. The information that the signal carries may be, for example, analog or digital information. The signal may be transmitted over a variety of different wired or wireless links, as is known. The signal may be stored on, or accessed or received from, a processor-readable medium. [0127] Many examples are described herein. Features of examples may be provided alone or in any combination, across various claim categories and types. Further, examples may include one or more of the features, devices, or aspects described herein, alone or in any combination, across various claim categories and types. For example, features described herein may be implemented in a bitstream or signal that includes information generated as described herein. The information may allow a decoder to decode a bitstream, the encoder, bitstream, and/or decoder according to any of the embodiments described. For example, features described herein may be implemented by creating and/or transmitting and/or receiving and/or decoding a bitstream or signal. For example, features described herein may be implemented a method, process, apparatus, medium storing instructions, medium storing data, or signal. For example, features described herein may be implemented by a TV, set-top box, cell phone, tablet, or other electronic device that performs decoding. The TV, set-top box, cell phone, tablet, or other electronic device may display (e.g. using a monitor, screen, or other type of display) a resulting image (e.g., an image from residual reconstruction of the video bitstream). The TV, set-top box, cell phone, tablet, or other electronic device may receive a signal including an encoded image and perform decoding. [0128] Local Illumination compensation (LIC) may be performed. LIC may model local illumination variation between a current block and its prediction block as a function of local illumination variation between a current block template and a reference block template. The parameters of the function may be denoted by a scale α and an offset β, which may form a linear equation, e.g., α*p[x]+β, to compensate
IDVC_ 2023P00519WO PATENT illumination changes. With reference to the example linear equation, p[x] may be a reference sample pointed to by a motion vector (MV) at a location x on a reference picture. The MV may be clipped with a wrap around offset taken into consideration, for example, if/when wrap around motion compensation is enabled. An LIC flag that may be signaled for AMVP mode to indicate the use of LIC. LIC parameters α and β may be derived based on current block template and a reference block template. [0129] Local illumination compensation may be used for uni-prediction inter CUs. Intra neighbor samples may be used in LIC parameter derivation. LIC may be disabled for blocks with less than a threshold number of luma samples (e.g., 32 luma samples). LIC parameter derivation may be performed (e.g., for non-subblock and affine modes), for example, based on the template block samples corresponding to the current coding unit (CU), e.g., instead of partial template block samples corresponding to a particular unit (e.g., first top-left 16x16 unit). Samples of the reference block template may be generated, for example, by using motion compensation (MC) with the block MV without rounding to integer-pel (pixel element) precision. [0130] LIC may be used for bi-prediction. An LIC mode may be used with bi-predictive CUs. One or more (e.g., two) different linear models may be applied to one or more (e.g., two) prediction blocks, which may (e.g., then) be combined to generate the bi-prediction samples of the current CU, for example, in accordance with Eq. (1), Eq. (2), and Eq. (3): ^^^^′[ ^^^^, ^^^^] = (1 − ^^^^) ∙ ^^^^0 ′ [ ^^^^, ^^^^] + ^^^^ ∙ ^^^^1 ′ [ ^^^^, ^^^^] (1) ^^^^0 ′ [ ^^^^, ^^^^] = ^^^^0 ∙ ^^^^0[ ^^^^, ^^^^] + ^^^^0 (2) ^^^^1 ′ [ ^^^^, ^^^^] = ^^^^1 ∙ ^^^1^ [ ^^^^, ^^^^] + ^^^^1 (3) With reference to Eq. (1), Eq. (2), and Eq. (3), ^^^^0 and ^^^^0, and ^^^^1 and ^^^^1 may indicate the scales and the offsets in L0 and L1, respectively; ^^^^ may indicate the weight (e.g., as may be indicated by the bi-prediction CU-level weight (BCW) index) for the weighted combination of L0 and L1 predictions. [0131] The (e.g., same) derivation scheme of the LIC mode may be reused and applied in an iterative method to derive the L0 and L1 LIC parameters. For example, the method may (e.g., first) derive the L0 parameters, e.g., by minimizing a difference between L0 template prediction ^^^^0 and the template ^^^^. The samples in ^^^^ may be updated by subtracting the corresponding samples in ^^^^0. The L1 parameters may be calculated, for example, to minimize the difference between L1 template prediction ^^^^1 and the updated template. The L0 parameter may be refined again, e.g., in the same way. [0132] An indication may be signaled for advanced motion vector prediction (AMVP) bi-predicted CUs for the indication of the LIC mode. The flag may be inherited for merge related inter CUs. The LIC mode may be disabled, for example, if/when decoder-side motion vector refinement (DMVR) (e.g., including multi-pass DMVR, adaptive DMVR, and affine DMVR) and/or bi-directional optical flow (BDOF) are applied.
IDVC_ 2023P00519WO PATENT [0133] Intra block copy coding may be performed. Intra block copy (IBC) may be used for screen content coding. IBC may improve the coding efficiency of screen content materials. Block matching (BM) may be performed at the encoder to find an optimal block vector (or motion vector) for a (e.g., each) CU, for example, since IBC mode may be implemented as a block level coding mode. A block vector may indicate a displacement from the current block to a reference block, which may be reconstructed inside the current picture. The luma block vector of an IBC-coded CU may be in integer precision. The chroma block vector may round to integer precision. The IBC mode (e.g., if/when combined with AMVR) may switch between MV precisions (e.g., between 1-pel and 4-pel motion vector precisions). An IBC-coded CU may be treated as a third prediction mode, e.g., other than intra or inter prediction modes. The IBC mode may be applicable to CUs with width and/or height smaller than or equal to a threshold number of luma samples (e.g., 64 luma samples). [0134] IBC mode may be signaled with an indication (e.g., a flag), e.g., at CU level. IBC mode may be signaled as IBC AMVP mode or IBC skip/merge mode. [0135] IBC mode may be signaled as IBC skip/merge mode. A merge candidate index may be used to indicate which of the block vectors in the list from neighboring candidate IBC coded blocks is used to predict the current block. The merge list may include spatial, history-based motion vector predictor (HMVP), and/or pairwise candidates. [0136] IBC mode may be signaled as IBC AMVP mode, also referred to as BVP mode herein. Block vector difference may be coded, for example, in the same way as a motion vector difference. The block vector prediction method may use one or more (e.g., two) candidates as predictors, for example, one from left neighbor and one from above neighbor (e.g., if IBC coded). A default block vector may be used as a predictor, for example, if/when one or more neighbors may not be available. A flag may be signaled to indicate the block vector predictor index. [0137] IBC may have a reference region. IBC may be implemented to limit memory consumption and/or decoder complexity. For example, IBC may allow (e.g., only) the reconstructed portion of the predefined area, e.g., including the region of the current coding tree unit (CTU) and/or some region of the left CTU. FIG.5 illustrates as example of the reference region for IBC Mode. As shown in FIG.5, a (e.g., each) block may represent a 64x64 luma sample unit. [0138] FIG.5 illustrates an example of current CTU processing order and available reference samples in the current and left CTU. One or more of the following may apply, for example, depending on the location of the current coding CU location within the current CTU. [0139] A current block may refer to already reconstructed samples in the current CTU and may also refer to the reference samples in the bottom-right blocks (e.g., 64x64 blocks) of the left CTU (e.g., using IBC mode), for example, if the current block falls into the top-left block (e.g., 64x64 block) of the current
IDVC_ 2023P00519WO PATENT CTU. The current block may (e.g., also) refer to the reference samples in the bottom-left block (e.g., 64x64 block) of the left CTU and the reference samples in the top-right block (e.g., 64x64 block) of the left CTU (e.g., using IBC mode). [0140] A current block may refer to already reconstructed samples in the current CTU and may also refer to the reference samples in the bottom-left block (e.g., 64x64 block) and bottom-right block (e.g., 64x64 block) of the left CTU (e.g., using IBC mode), for example, if the current block falls into the top-right block (e.g., 64x64 block) of the current CTU and if luma location (0, 64) relative to the current CTU has not yet been reconstructed. A current block may refer to already reconstructed samples in the current CTU and may also refer to reference samples in bottom-right block (e.g., 64x64 block) of the left CTU, for example, if the current block falls into the top-right block (e.g., 64x64 block) of the current CTU and if luma location (0, 64) relative to the current CTU has been reconstructed. [0141] A current block may refer to the already reconstructed samples in the current CTU and may also refer to the reference samples in the top-right block (e.g., 64x64 block) and bottom-right block (e.g., 64x64 block) of the left CTU (e.g., using IBC mode), , for example, if the current block falls into the bottom-left block (e.g., 64x64 block) of the current CTU and if luma location (64, 0) relative to the current CTU has not yet been reconstructed. A current block may refer to the already reconstructed samples in the current CTU and may also refer to the reference samples in the bottom-right 64x64 block of the left CTU (e.g., using IBC mode), for example, if the current block falls into the bottom-left block (e.g., 64x64 block) of the current CTU and if luma location (64, 0) relative to the current CTU has been reconstructed. [0142] A current block may (e.g., only) refer to the already reconstructed samples in the current CTU (e.g., using IBC mode), for example, if the current block falls into the bottom-right block (e.g., 64x64 block) of the current CTU. [0143] The foregoing restriction(s) may allow the IBC mode to be implemented using local on-chip memory for hardware implementations. [0144] An IBC merge/AMVP list may be constructed. An IBC merge/AMVP list construction may be performed. An IBC merge/AMVP candidate may be inserted into the IBC merge/AMVP candidate list, for example, (e.g., only) if the IBC merge/AMVP candidate is valid. Above-right, bottom-left, and/or above-left spatial candidates and/or a (e.g., one) pairwise average candidate may be added into the IBC merge/AMVP candidate list. Template based adaptive reordering (ARMC-TM) may be applied to an IBC merge list. [0145] An HMVP table size for IBC may be, for example, 25 entries. IBC merge candidates (e.g., up to 20 IBC merge candidates) may be derived with full pruning. IBC merge candidates may be reordered together, e.g., after derivation with full pruning. A set of first candidates (e.g., the first 6 candidates with the
IDVC_ 2023P00519WO PATENT lowest template matching costs) may be selected as the final candidates in the IBC merge list, e.g., after reordering. [0146] The zero vectors’ candidates to pad the IBC Merge/AMVP list may be replaced with a set of BVP candidates located in the IBC reference region. A zero vector may be invalid as a block vector in IBC merge mode. Zero vectors may be discarded as BVP in the IBC candidate list. [0147] FIG.6 illustrates an example of padding candidates for the replacement of the zero-vector in the IBC list. Three candidates may be located on the nearest corners of the reference region. Three additional candidates may be determined in the middle of the three sub-regions (A, B, and C). Candidate coordinates may be determined by the width and height of the current block and the ΔX and ΔY parameters, e.g., as depicted by example in FIG.6. [0148] FIG.7 illustrates an example of an extended reference region for IBC. IBC may have a reference region. The reference region for IBC may extend to two CTU rows above the CTU being processed by the encoder or the encoder. FIG.7 illustrates an example of the reference area for coding CTU (m,n). CTU (m,n) may be coded based on a reference area that includes CTUs with index (m–2,n–2)…(W,n–2),(0,n– 1)…(W,n–1),(0,n)…(m,n). W may denote the maximum horizontal index within the current tile, slice or picture. The per-sample block vector search (or called local search) range may be limited to [–(C << 1), C >> 2] horizontally and [–C, C >> 2] vertically to adapt to the reference area extension. C may denote the CTU size. [0149] IBC may be implemented with template matching. Template matching (TM) based motion search and refinement may be applied to the case of IBC. [0150] An IBC-template matching (IBC-TM) merge mode may be used. An IBC-TM merge mode may involve a merge candidate list for Block Vector (BV) prediction, which may be different from the merge candidate list used by (e.g., regular) IBC merge mode. The candidates may be selected according to a pruning method with a motion distance between the candidates, e.g., as in the (e.g., regular) TM merge mode. The zero motion candidates may be replaced, for example, by (-W, 0), (0, -H), (-W, -H) MVs. [0151] The selected candidates in the IBC-TM merge mode may be refined, for example, with a template matching method. The TM-merge flag may be signaled to indicate the template matching merge IBC mode. [0152] Candidates (e.g., up to three (3) candidates) in the IBC-TM AMVP mode may be selected from the IBC-TM merge list. A (e.g., each) candidate may be refined, for example, according to the (e.g., usual) template matching method. Refined candidates may be sorted, for example, according to their resulting TM cost.
IDVC_ 2023P00519WO PATENT [0153] TM refinement may be performed at integer pel position, for example, if/when used for IBC. TM refinement may be performed at integer or 4-pel precision (e.g., depending on the AMVR value), for example, if/when used for IBC-TM AMVP mode. The refinement may be performed within the existing IBC reference area. [0154] IBC mode may interact with other coding tools, such as pairwise merge candidate, history-based motion vector predictor (HMVP), combined intra/inter prediction mode (CIIP), merge mode with motion vector difference (MMVD), and geometric partitioning mode (GPM). For example, IBC may be used with pairwise merge candidate and HMVP. A new pairwise IBC merge candidate may be generated, for example, by averaging (e.g., two) IBC merge candidates. IBC motion may be inserted into a history buffer for future referencing, e.g., for HMVP. In some examples, IBC may not be used in combination with an affine motion inter tool. IBC may be used in combination with combined inter-intra prediction (CIIP), MMVD, and/or geometric partitioning mode (GPM). In some examples, IBC may not be allowed for chroma coding blocks, e.g., if/when a DUAL_TREE partition is used. [0155] The current picture may not be included as a reference picture in the reference picture list 0 for IBC prediction, for example. The derivation process of motion vectors for IBC mode may exclude (e.g., all) neighboring blocks in inter mode and vice versa. [0156] The following IBC functionality may be applied. IBC may share the (e.g., same) process as in (e.g., regular) MV merge, including with pairwise merge candidate and history-based motion predictor, but may disallow temporal motion vector prediction (TMVP) and zero vector, e.g., because they are invalid for IBC mode. A separate HMVP buffer (e.g., five (5) candidates each) may be used for (e.g., conventional) MV and IBC. Block vector constraints may be implemented, e.g., in the form of a bitstream conformance constraint, the encoder may use to ensure that invalid vectors are not present in the bit-stream. Merge mode may not be used, for example, if the merge candidate is invalid (e.g., out of range or zero (0)). A bitstream conformance constraint may be expressed, for example, in terms of a virtual buffer (e.g., as described herein). IBC may be handled as inter mode, for example, for deblocking. AMVR may not use quarter-pel, for example, if the current block is coded using IBC prediction mode. AMVR may be signaled (e.g., only) to indicate whether MV is inter-pel or 4 integer-pel, for example, if the current block is coded using IBC prediction mode. The number of IBC merge candidates may be signaled in the slice header, for example, separately from the numbers of regular, subblock, and/or geometric merge candidates. [0157] IBC merge mode with block vector differences (IBC-MBVD) may be implemented. Merge with motion vector difference (MMVD) may be used in inter-predicted blocks. Affine-MMVD and GPM-MMVD may be deployed, for example, as an extension of (e.g., regular) MMVD mode. MMVD mode has been extended to the IBC merge mode.
IDVC_ 2023P00519WO PATENT [0158] IBC-MBVD may be implemented with a motion vector difference distance set, for example, {1- pel, 2-pel, 4-pel, 8-pel, 12-pel, 16-pel, 24-pel, 32-pel, 40-pel, 48-pel, 56-pel, 64-pel, 72-pel, 80-pel, 88-pel, 96-pel, 104-pel, 112-pel, 120-pel, 128-pel}. The BVD directions may be two horizontal and two vertical directions. [0159] The base candidates may be selected from a set of candidates (e.g., the first five candidates) in the reordered IBC merge list. The possible (e.g., all the possible) MBVD refinement positions (e.g., 20×4) for a (e.g., each) base candidate may be reordered, for example, based on the sum of absolute differences (SAD) cost between the template (e.g., one row above and one column left to the current block) and its reference for a (e.g., each) refinement position. The top (e.g., eight (8)) refinement positions with the lowest template SAD costs may be kept as available positions, e.g., for MBVD index coding. The MBVD index may be binarized by the rice code, e.g., with the parameter equal to one (1). [0160] IBC and LIC may be used jointly. IBC may be used with the inter prediction enhancement tool called LIC. LIC is an inter prediction technique to model local illumination variation between a current block and its prediction block as a function of local illumination variation between current block template and reference block template. The parameters of the function may be denoted by a scale α and an offset β. A linear equation, e.g., α*p[x]+β, may be used to compensate illumination changes, where p[x] may be a reference sample pointed to by an MV at a location x on a reference picture. The MV may be clipped with a wrap-around offset taken into consideration, for example, when wrap around motion compensation is enabled. Parameters α and β may not utilize signaling overhead, for example, since α and β may be derived based on the current block template and the reference block template. An LIC flag may be signaled for AMVP mode to indicate the use of LIC. [0161] Local illumination compensation may be used for uni-prediction inter CUs. Intra neighbor samples may be used in LIC parameter derivation. LIC may be disabled for blocks with less than a threshold number of luma samples (e.g., 32 luma samples). LIC parameter derivation may be performed e.g., (for non-subblock and affine modes), for example, based on the template block samples corresponding to the current CU, e.g., instead of partial template block samples corresponding to first top- left unit (e.g., 16x16 unit). Samples of the reference block template may be generated, for example, by using MC with the block MV, e.g., without rounding to integer-pel precision. [0162] Intra block copy with local illumination compensation (IBC-LIC) may compensate the local illumination variation within a picture between the CU coded with IBC and its prediction block, for example, with a (e.g., linear) equation. The parameters of the (e.g., linear) equation may be derived, for example, in the same or a similar way as LIC for inter prediction (e.g., except that the reference template may be generated using a block vector in IBC-LIC). IBC-LIC may be applied to IBC AMVP mode and/or IBC merge
IDVC_ 2023P00519WO PATENT mode. An IBC-LIC flag may be signaled (e.g., for IBC AMVP mode) to indicate the use of IBC-LIC. The IBC-LIC flag may be inferred (e.g., for IBC merge mode) from the merge candidate. [0163] IBC may be adapted to camera-captured video content. The IBC coding mode may be used (e.g., by default) for the coding of camera-captured content. One or more adaptations may be used to make the IBC coding mode perform well, e.g., in terms of compression efficiency, such as high-level tool control, encoder optimization, fraction-pel extension on IBC. [0164] High level tool control may be used to improve IBC coding mode performance. IBC merge modes may be disabled for natural content. A sequence parameter set (SPS) level flag may be implemented to disable the associated CU level signaling. IBC AMVP modes (e.g., only IBC AMVP modes) may be activated, for example, when indicated (e.g., explicitly indicated) by the SPS flag. RR-IBC, TM-IBC, and/or IBC-CIIP may be disabled for natural content. SPS flags corresponding to RR-IBC and TM-IBC may be implemented. IBC may be applied to intra slices for natural content, which may be indicated by high-level syntax to remove CU level signaling of IBC flag. IBC may be applied to slices for screen contents. [0165] IBC block vector search may be optimized (e.g., at the encoder) for natural content. The rate distortion optimization (RDO) process may be skipped for an IBC AMVP mode, for example, if the SAD cost for the RDO process is (e.g., much) worse than the lowest SAD cost of (e.g., all) Intra modes. IBC AMVP modes may not be evaluated, for example, if/when the (e.g., best) Intra mode has less than a threshold number of nonzero coefficients (e.g., three (3) nonzero coefficients). Partitioning depth in an inter slice may be skipped, for example, depending on the picture order count (POC) distance between the current picture and its nearest reference picture. The POC distance may be set equal to zero (0), for example, if/when IBC is enabled from SPS level. The POC distance set equal to zero (0) may not align with the configuration used in common test conditions (CTC) for random access and low delay. In this test, for inter slices, the true POC distance may be used, e.g., instead of setting to zero (0). [0166] Fraction-pel extension on IBC may be used to improve IBC coding mode performance. The representation of IBC block vectors may be extended to fractional-pel resolution. An interpolation filter may be used to derive the prediction samples located at a non-integer phase in the reconstructed area of the current frame. The option of block vector resolutions may include quarter-pel resolution, e.g., in additional to full-pel and 4-pel resolution. The first bin of AMVR syntax may be signaled (e.g., similar to inter AMVR syntax), for example, to indicate whether BV is in quarter-pel resolution. The second bin may be signaled, for example, to switch between full-pel and 4-pel resolutions. The interpolation filters applied to the luma and chroma components of IBC blocks may be, for example, the 8-tap luma filter and the same chroma filter as used in motion compensation, respectively, with possible exceptions. For example, a 2-tap bilinear interpolation filter may be applied to generating template prediction blocks, for example, if/when needed in
IDVC_ 2023P00519WO PATENT IBC-related coding tools. Reference sample padding may be used, for example, if/when some of them are not available or located outside the valid IBC reference area in the current frame. Reference sample padding, e.g., if/when needed, may be performed in the horizontal direction (e.g., first) and then in the vertical direction. [0167] Bi-predictive IBC may be implemented. A Bi-predictive IBC prediction mode may include methods with types of bi-predictive IBCs. For example, a first method (Method 1) may include an IBC BVP-merge mode. A second method (Method 2) may include a Bi-predictive IBC merge mode. [0168] Method 1 may derive the two (e.g., required) BVs from IBC block vector prediction (BVP) mode (also referred to as IBC AMVP herein) and IBC merge mode (e.g., similar to the MV derivation of AMVP- merge mode that combines an AMVP motion vector predictor for a reference list and an inter merge candidate for the other reference list) to form a bi-predicted inter CU. Two different indices for the IBC BVP mode and the IBC merge candidate may be signaled from the encoder to the decoder, respectively, taken from IBC AMVP candidate list and IBC merge candidate list. [0169] Method 2 may derive the two (e.g., required) BVs from the IBC merge candidate list, for example, by utilizing two different IBC merge indices. The two indices may be signaled from the encoder to the decoder. The target of the bi-predictive IBC merge mode may be, for example, IBC-regular merge, IBC merge mode with block vector difference (IBC-MBVD), and IBC geometric partitioning mode (IBC-GPM), which may be enabled for screen content (e.g., by default). Bi-predictive IBC-MBVD may be enabled in natural and screen content, while bi-predictive IBC-GPM may be enabled (e.g., only) in screen content. [0170] The methods (e.g., method 1 and method 2) may be implemented based on one or more of the following. The methods may reuse the IBC merge candidate list construction scheme for uni-predictive IBC merge mode. The methods may use BV refinement. For example, the methods may enable the IBC with template matching. The methods may use compensation. For example, the methods may generate final IBC prediction samples with a simple (1:1) average of bi-predictive IBC samples. The methods may store the two BVs in BV storage, e.g., if/when the bi-predictive IBC is enabled. The methods may use signaling. For example, a control flag of bi-predictive IBC may be signaled at a slice level in I slice (e.g., not signaled in B and P slices). Reconstructed-Reordered IBC may be disabled, for example, if/when the bi-predictive IBC is enabled. The methods may be enabled in chroma component blocks of the single tree. [0171] Intra template matching prediction (Intra TMP) prediction mode may be implemented. Intra TMP is a (e.g., special) intra prediction mode that copies a (e.g., the best) prediction block from the reconstructed part of the current frame, whose L-shaped template matches the current template. An encoder search a (e.g., predefined) search range for a (e.g., the most) similar template to the current template in a reconstructed part of the current frame. The encoder may use the corresponding block as a
IDVC_ 2023P00519WO PATENT prediction block. The encoder may signal usage of the Intra TMP mode, for example, so that the decoder may perform the same prediction operation at the decoder side. [0172] FIG.8 illustrates an example of an intra template matching search area. The prediction signal may be generated by matching the L-shaped causal neighbor of the current block with another block in a (e.g., predefined) search area, as shown by example in FIG.8. The search are may include several regions. A first region R1 may indicate the current CTU, a second region R2 may indicate the top-left CTU, a third region R3 may indicate the above CTU, and a fourth region R4 may indicate the left CTU. SAD may be used as a cost function. [0173] The decoder may search within a (e.g., each) region for the template that has the least SAD with respect to the current one and use its corresponding block as a prediction block. [0174] The dimensions of (e.g., all) regions (SearchRange_w, SearchRange_h) may be set proportional to the block dimension (BlkW, BlkH), for example, to have a (e.g., fixed) number of SAD comparisons per pixel. The dimensions of regions may be determined, for example, in accordance with Eq. (4) and Eq. (5): SearchRange_w = ^^^^ * BlkW (4) SearchRange_h = ^^^^ * BlkH (5) With reference to Eq., (4) and Eq. (5), ‘ ^^^^’ may be a constant that controls the gain/complexity trade-off. In some examples, ‘ ^^^^’ may be equal to five (5). [0175] An intra template matching tool may be enabled for CUs with a size less than or equal to a threshold size, such as 64 in width and/or height. The maximum CU size for intra template matching may be configurable. [0176] The Intra template matching prediction mode may be signaled at CU level, for example, through a (e.g., dedicated) flag, e.g., if/when DIMD is not used for current CU. [0177] Intra TMP may be implemented with a multiple prediction candidate. An Intra TMP prediction mode may allow signaling an Intra TMP predictor used for a current CU, for example, through a (e.g., dedicated) syntax element (e.g., intra_tmp_idx). The index may indicate the Intra TMP predictor used among intra TMP predictors, which may be found through a TM search considering L-shape template, Left- only template area, or Top-only template area. [0178] FIG.9 illustrates an example of multiple Intra TMP candidates. [0179] Intra TMP prediction candidates may be added. Additional intra TMP candidates may include, for example, a weighted average of multiple/several Intra TMP candidate predictors found during the Intra TMP template matching search. An example of generating additional intra TMP candidates is provided. [0180] Multiple matched blocks may be generated during the IntraTMP search. A subsampled IntraTMP search process may be performed. A candidate list may be (e.g., initially) generated for (e.g., 30) matched
IDVC_ 2023P00519WO PATENT blocks with the smallest template SAD. A (e.g., full pixel) refinement search may be performed within a (e.g., small) 3x3 region around each of the (e.g., 30) matched blocks. The best (e.g., three (3)) candidate matched blocks measured by template SAD across (e.g., all) refinement regions may be selected. [0181] Candidate matched blocks may be selected for fusion. A threshold may be used, for example, in accordance with Eq. (6), to judge whether and/or which of the best (e.g., three (3)) candidate matched blocks should be used for fusion. Threshold = ^^^^ ^^^^ ^^^^1 << 1 (6) With reference to Eq. (6), ^^^^ ^^^^ ^^^^1 may be the smallest template SAD of the (e.g., three) candidate matched blocks. Candidate matched blocks with SAD <= Threshold may be used for fusion, which may determine the number of candidates matched blocks. [0182] A fusion weight may be calculated for each of the selected matched blocks. Selected matched blocks (e.g., blocks to be fused) may be fused with weights. A fusion weight may be calculated based on the SAD associated with selected matched blocks. The weights may be calculated, for example, in accordance with Eq. (7) and Eq. (8):
(8) Division operations may be replaced by an integer look-up table (LUT), for example, to reduce the implementation cost. [0183] The final fused predictor may be determined, for example, in accordance with Eq. (9):
With reference to Eq. (9), ^^^^ ^^^^ may be the ^^^^ ^^^^ℎ matched block, and n may be the number of blocks selected for fusion. The final predictor may be calculated in accordance with Eq. (10), for example, if/when (e.g., only) one matched block remains after selecting candidate matched blocks for fusion: ^^^^ ^^^^ ^^^^ ^^^^ ^^^^ ^^^^ ^^^^ = ^^^^1 ^^^^ ^^^^ ^^^^ ^^^^ + ^^^^2 ^^^^ ^^^^ ^^^^ ^^^^ ^^^^ ^^^^ (10)
IDVC_ 2023P00519WO PATENT With reference to Eq. (10), ^^^^ ^^^^ ^^^^ ^^^^ may be the (e.g., single) matched block and ^^^^ ^^^^ ^^^^ ^^^^ ^^^^ ^^^^ may be the intra predictor derived by the Planar mode. In some examples, the weights in Eq. (10) may be set as ^^^^ 1 = 7/8 and ^^^^2 = 1/8. [0184] A CU level flag may be added to signal whether an IntraTMP CU is predicted by the example fusion method or by another method (e.g., the original method). [0185] Intra TMP and IBC may be used with a linear filter model (Intra TMP-FLM and IBC-FLM prediction modes). Intra TMP may be used in combination with a convolution filtering method, e.g., as described herein. [0186] In some examples, a 6-tap filter, e.g., including a 5-tap plus a sign shape spatial component and a bias term, may be adaptively used to enhance an Intra TMP block prediction. The input to the spatial 5- tap component of the filter may include a center C sample in the reference block, which may be at corresponding locations with the sample in the current block to be predicted, along with above/north (N), below/south (S), left/west (W) and right/east (E) neighbors, as illustrated by example in FIG.10. [0187] FIG.10 illustrates an example of a spatial part of a filter. [0188] Output of the filter may be calculated, for example, in accordance with Eq. (11): predLumaVal = c0C + c1N + c2S + c3E + c4W + c5B (11) With reference to Eq. (10), the bias term B may represent a scalar offset between the input and output. The bias term B may be set to a middle luma value (e.g., 512 for 10-bit content). The filter coefficients ci may be calculated, for example, by minimizing the mean squared error (MSE) between the reference template and current template, e.g., as shown by example in FIG.11. Template size and shapes may be the same as in intraTMP. The template size used for training may be, for example, four (4) lines above and to the left of the current block, e.g., depending on their availability. The area with a hatch pattern may support the “side samples” of the plus shaped spatial filter. The “side sample” area may be padded, for example, if/when in unavailable areas. [0189] FIG.11 illustrates an example of the reference area that may be used to derive the filter coefficients. [0190] Usage of the Intra TMP-FLM mode may be signaled, for example, by a coded CU level flag. Intra TMP-FLM may be considered a sub-mode of Intra TMP. An Intra TMP-FLM flag may be signaled, for example, (e.g., only) if the Intra TMP flag is true. [0191] The filtering method, e.g., as described herein, may include applying the linear filter model to IBC predicted blocks. The filtered mode may be used as an additional mode for non-merge IBC blocks. For non-merge blocks, the mode may not be applied together with IBC-LIC, IBC-CIIP, or RR-IBC. For IBC
IDVC_ 2023P00519WO PATENT merge modes, the filtering mode may be inherited, for example, if/when a merge mode list is constructed, which may avoid extra signaling. [0192] Adaptive usage of the LIC of a linear filter model for an IBC predicted block, e.g., together with block-level signaling of the prediction mode used, may lead to increased compression performances. [0193] The combined use of Intra TMP with a linear filter model may be implemented, for example, with respect to the Intra TMP prediction mode. [0194] Performing video coding using IBC bi-prediction with bi-predictive LIC may improve compression performance, for example, by improving the bi-predictive IBC mode. [0195] Bi-directional LIC may be supported for bi-predictive IBC coding units. A bi-predictive LIC model may be derived for a CU coded in IBC mode, e.g., similar to a method for inter CU. The bi-predictive LIC mode may be selected/derived at CU-level, for example, according to whether the CU is in BVP-merge mode or in bi-predictive IBC merge mode. Several examples are described herein to derive the bi- predictive LIC model and to select/derive the bi-predictive LIC mode. [0196] A bi-predictive LIC model may be computed. In some examples (e.g., with a bi-predictive IBC CU with two block vectors), a bi-predictive LIC may include deriving two (2) linear models, respectively, for predictors 0 and 1. Final prediction of the current block may be computed as the average of the two unidirectional predictions, which involves each derived linear model. [0197] In some examples, the two linear models may be iteratively computed. [0198] In some examples (e.g., where one of the two block vectors is fractional), (e.g., only) integer-pel positions may be used to form the corresponding template samples, e.g., to reduce complexity. [0199] In some examples, an extended IBC-LIC mode may be used for bi-predictive LIC. For example, a partial template mode (e.g., top-only or left-only) may be signaled and used. The bi-predictive LIC model computation may (e.g., also) consider the signaled partial template area, e.g., for both predictors. In some examples (e.g., in a further variant), such as in multi-model IBC-LIC mode, the multi-model LIC models may be derived for both predictors of the bi-predictive IBC prediction process. [0200] A bi-predictive IBC mode may be derived/signaled, for example, at CU level. [0201] In some examples, a LIC flag may be a signal for CUs coded in IBC BVP-merge mode, e.g., to indicate if LIC is or is not used for the considered CU. [0202] In some (e.g., alternative) examples, such as for a bi-predictive CU in BVP-merge mode, the signaled LIC flag may be associated (e.g., only) with the BV coded in BVP mode, and may not apply to the IBC merge part of the Cu’s BV information. Consequently, the use of bi-predictive for the considered CU may be deduced from the signal LIC flag (e.g., BVP part) and/or the inherited LIC flag (e.g., merge part). Bi-predictive LIC is applied, for example, if the (e.g., both) flags are true. Otherwise, if one of the (e.g., two)
IDVC_ 2023P00519WO PATENT flags is true, uni-predictive LIC may be applied to the predictor associated with the true LIC flag. LIC may not take place for the considered CU, for example, if the (e.g., both) LIC flags are false. [0203] In some (e.g., alternative) examples, such as for a bi-predictive IBC BVP-merge CU, a bi- predictive LIC flag for the considered CU may be inferred to the value of the LIC flag inherited in the IBC merge part of the current CU. [0204] In some examples, such as for a CU in IBC-merge mode, multiple (e.g., two) IBC flags for a current CU may be derived from a (e.g., each) IBC merge candidate derived with a (e.g., each) IBC merge index. Bi-predictive LIC may (e.g., then) be used, for example, if the (e.g., both) derived LIC flags are true. Otherwise, uni-predictive LIC may be used in association with the BV derived together with a true LIC flag. [0205] In some (e.g., alternative) examples, such as for a bi-predictive IBC merge CU, bi-predictive LIC may be used based on whether (e.g., as soon as) at least one derived LIC flag is true. [0206] In some (e.g., alternative) examples, such as for a bi-predictive IBC merge CU, bi-predictive LIC may be disallowed for a current CU based on whether (e.g., as soon as) at least one derived LIC flag is false. [0207] A bi-predictive LIC IBC mode may be controlled, for example, with high-level control(s). In some examples, the bi-predictive LIC mode for bi-predictive IBC CUs may be activated/deactivated at a sequence level (e.g., through a dedicated SPS flag). In some examples, the bi-predictive LIC mode for bi- predictive IBC CUs may be activated/deactivated at a picture level (e.g., through a dedicated picture header flag). In some examples, the bi-predictive LIC mode for bi-predictive IBC CUs may be activated/deactivated at a slice level (e.g., through a dedicated slice header flag). In some examples, the bi-predictive LIC mode for bi-predictive IBC CUs may be activated/deactivated at a sub-picture, tile, or tile group level. [0208] A bi-predictive LIC model may be derived and/or applied for a CU predicted in bi-predictive IBC mode. [0209] A bi-predictive LIC model computation may be performed for a bi-predictive IBC CU. Three example methods of computation are provided herein. [0210] In some examples (e.g., Method 1), one or more of the following operations may apply to a bi- predictive LIC prediction process in a bi-predicted IBC CU. A current CU may have two (2) BVs, respectively, pointing to two prediction blocks ^^^^0 and ^^^1^. A first LIC model ( ^^^^0, ^^^^0) may be derived for ^^^^0. An LIC-based prediction ^^^^0 ′ of the current block may be computed, for example, in accordance with Eq. (12):
IDVC_ 2023P00519WO PATENT A second LIC model ( ^^^^1, ^^^^1) may be derived for ^^^1^. An LIC-based prediction ^^^1^′ of the current block may be computed, for example, in accordance with Eq. (13): ^^^1^′ = ^^^^1 ^^^1^ + ^^^^1 (13) A final bi-prediction of the current CU may be computed, for example, in accordance with Eq. (14): ^^^^ ′ = ( 1 − ^^^^ ) ^^^^ ′ + ^^^^ ^^^^ ′ , wit 1 0 1 h typically ^^^^ = 2 (14) [0211] In some examples (e.g., Method 2), one or more of the following operations in an iterative process (e.g., similar to an iterative process used for inter block), may apply to bi-predictive IBC CU. A first LIC model ( ^^^^0, ^^^^0) may be derived for ^^^^0. The first LIC model may be applied to samples of a first template ^^^^0, for example, in accordance with Eq. (15): ^^^^0 ′ = ^^^^0 ^^^^0 + ^^^^0 (15) ^^^^0 ′ may be subtracted from the current CU template ^^^^, for example, in accordance with Eq. (16): ^^^^′ = ^^^^ − ^^^^0 ′ (16) The second LIC model
may be derived for ^^^1^, for example, based on templates ^^^^′ and ^^^1^ (e.g., template of second IBC prediction block). The second LIC model may be applied to samples of the second template ^^^1^, for example, in accordance with Eq. (17):
The first LIC model may be refined, for example, by subtracting ^^^1^′ from ^^^^ and recomputing the first LIC model ( ^^^^0, ^^^^0) for ^^^^0. The LIC-based prediction ^^^^0 ′ of the current block may be computed, for example, in accordance with Eq. (18): ^^^^0 ′ = ^^^^0 ^^^^0 + ^^^^0 (18)
IDVC_ 2023P00519WO PATENT The LIC-based prediction ^^^1^′ of the current block may be computed, for example, in accordance with Eq. (19): ^^^1^′ = ^^^^1 ^^^1^ + ^^^^1 (19) - Compute The final bi-prediction of the current CU may be computed, for example, in accordance with Eq. (20):
With reference to Eq. (20), in some examples, ^^^^ =
[0212] In some examples (e.g., Method 3), a (e.g., only one) LIC model with a (e.g., one) set of LIC parameters may be derived and/or may be applied to bi-predictive IBC CU. Compute the weighted reference template may be computed, for example, in accordance with Eq. (21): ^^^^′ = (1 − ^^^^) ^^^^0 + ^^^^ ^^^1^ (21) With reference to Eq. (21), in some examples, ^^^^ =
The weighted bi-prediction samples may be computed from two prediction blocks, for example, in accordance with Eq. (22): ^^^^′ = (1 − ^^^^) ^^^0^ + ^^^^ ^^^1^ (22) With reference to Eq. (22), in some examples, ^^^^ =
Derive A (e.g., one single) LIC model ( ^^^^, ^^^^) may be derived for ^^^^′, for example, based on weighted reference template ^^^^′ and current CU template ^^^^. The single LIC model ( ^^^^, ^^^^) may be applied to the weighted prediction samples ^^^^′ to obtain the final bi- prediction of the current CU, for example, in accordance with Eq. (23): ^^^^′′ = ^^^^ ^^^^′ + ^^^^ (23) [0213] IBC bi-prediction with bi-predictive LIC may be adapted to fractional IBC block vectors. In some examples, one of the two block vectors may be fractional, e.g., represented with an accuracy level finer than the integer-pel precision. Integer-pel positions (e.g., only integer-pel positions) may be used to form the corresponding template samples, for example, to reduce complexity. [0214] A bi-predictive LIC model may be derived, for example, for LIC multi-mode. An IBC-LIC mode may be used for bi-predictive LIC. [0215] Multiple (e.g., three) modes for IBC-LIC may be added to further improve the coding performance. The first two modes may be related to using different template shapes in the parameters’
IDVC_ 2023P00519WO PATENT derivation. IBC-LIC may use the top and/or left templates to derive the parameters. IBC-LIC may use the top-only, left-only, or top and left templates for deriving model parameters. [0216] IBC-LIC may use the multi-model linear model (MMLM) mechanism, which may allow IBC-LIC to have multiple (e.g., two) linear models in one CU. [0217] A large block-size constraint may be avoided/removed for IBC-LIC. For example, IBC-LIC modes may be applied to a CU whose block size is larger than 32. [0218] An example of signaling in the AMVP mode is summarized in Table 1. Table.1 – Example of IBC-LIC signalling Value Mode 0 Not IBC-LIC 100 Default IBC-LIC 101 Multi-models IBC-LIC 110 Top-only IBC-LIC 111 Left-only IBC-LIC [0219] A partial template mode (e.g., opt-only or left-only) may be signaled and used, for example, with respect to the bi-predictive LIC mode for bi-predictive IBC CUs. The bi-predictive LIC model computation may (e.g., also) consider the signaled partial template area, e.g., for both predictors. In some examples, such as multi-model IBC-LIC mode, the multi-model LIC models may be derived for both predictors of the bi-predictive IBC prediction process. [0220] A bi-predictive LIC model may be derived, used, and/or usage may be signaled for a CU predicted in bi-predictive IBC mode. A variety of example methods are described for use to signal and/or derive the activation of the bi-predictive LIC mode for bi-predictive CUs. [0221] In some examples, an LIC flag may be signaled for CUs coded in the IBC BVP-merge mode, for example, to indicate if LIC is used or not used for the considered CU. Bi-predictive LIC may be used for the concerned CU, for example, if the signaled flag is true. Bi-predictive LIC may not be used for the concerned CU, for example, if the signaled flag is false. [0222] In some (e.g., alternative) examples, such as for a bi-predictive CU in BVP-merge mode, the signaled LIC flag may be associated with (e.g., only) the BV coded in BVP mode, and may not apply to the IBC merge part of the Cu’s BV information. Consequently, the use of bi-predictive for the considered CU may be deduced from the signal LIC flag (e.g., BVP part) and/or the inherited LIC flag (e.g., merge part). Bi-predictive LIC may be applied, for example, if both flags are true. Otherwise, if one of the two flags is true, a uni-predictive LIC may apply a predictor associated with the true LIC flag. LIC may not take place for a considered CU, for example, if both LIC flags are false.
IDVC_ 2023P00519WO PATENT [0223] In some (e.g., alternative) examples, such as for a bi-predictive IBC BVP-merge CU, a bi- predictive LIC flag for the considered CU may be inferred to the value of the LIC flag inherited in the IBC merge part of the current CU. A LIC flag may not (e.g., need to) be signaled, for example, if LIC flag inheritance from uni-predictive IBC CUs is configured or takes place/occurs for the bi-predictive LIC mode of bi-predictive IBC coding units. [0224] In some examples, such as a CU in IBC-merge mode, multiple (e.g., two) IBC flags for a current CU may be derived from an (e.g., each) IBC merge candidate derived with an (e.g., each) IBC merge index. Bi-predictive LIC may (e.g., then) be used, for example, if the (e.g., both) derived LIC flags are true. Otherwise, if at least one derived LIC flag is true and at least one LIC flag is false, uni-predictive LIC may be used in association with the BV derived together with the true LIC flag. [0225] In some examples, such as for a bi-predictive IBC merge CU, bi-predictive LIC may be used based on whether (e.g., as soon as) at least one derived LIC flag is true. [0226] In some (e.g., alternative) examples, such as for a bi-predictive IBC merge CU, bi-predictive LIC may be disallowed for a current CU based on whether (e.g., as soon as) at least one derived LIC flag is false. [0227] A bi-predictive LIC method applied to bi-predictive IBC coding units may (e.g., also) be applied to an IBC filtering method (e.g., as may be described herein). Method 1, Method 2, and/or Method 3, as described herein with reference to Eq. (12) – (23), may be applied, for example, in the context of the IBC filtering process. [0228] For example, a set of convolutional cross-component model (CCCM) filtering parameters may be derived, respectively associated with each prediction block of the current CU. The filtering parameters may (e.g., then) be computed, for example, based on the template area of the current CU, and on the template of each prediction block separately, e.g., as in Method 1 described herein. [0229] For example, Method 2 may be adapted to the context of an IBC filtering process. An iterative approach similar to Method 2 may be employed to derive CCCM filtering parameters. A first derivation of filter parameters may be performed between the current block template and a first prediction block’s template. The filtered first prediction block’s template may be subtracted from the current block’s template. The second filter parameters may be derived between a second prediction block template and a modified template of the current block. A final refinement of filter parameters may (e.g., then) be applied for the first prediction block’s template. The bi-prediction of the current block may be computed, for example, as follows. A (e.g., each) prediction block may undergo CCM filtering, e.g., with CCCM filter parameters computed on its template. The final prediction of the current block may (e.g., then) be computed as the (e.g., weighted) average of the two filtered prediction blocks.
IDVC_ 2023P00519WO PATENT [0230] For example, Method 3 may be adapted to the context of an IBC filtering process. CCCM filtering parameters may be computed between the (e.g., weighted) average of the template of the two prediction blocks used to bi-predict the current CU. CCCM filtering parameters may (e.g., then) be applied to the (e.g., weighted) average of the two prediction blocks. [0231] Although features and elements are described above in particular combinations, one of ordinary skill in the art will appreciate that each feature or element can be used alone or in any combination with the other features and elements. In addition, the methods described herein may be implemented in a computer program, software, or firmware incorporated in a computer-readable medium for execution by a computer or processor. Examples of computer-readable media include electronic signals (transmitted over wired or wireless connections) and computer-readable storage media. Examples of computer-readable storage media include, but are not limited to, a read only memory (ROM), a random access memory (RAM), a register, cache memory, semiconductor memory devices, magnetic media such as internal hard disks and removable disks, magneto-optical media, and optical media such as CD-ROM disks, and digital versatile disks (DVDs). A processor in association with software may be used to implement a radio frequency transceiver for use in a WTRU, UE, terminal, base station, RNC, or any host computer.