EP4736418A1 - Intra sub-partitions (isp) combination with intra block copy (ibc) - Google Patents

Abstract

Systems, methods, and instrumentalities are disclosed for performing video encoding and/or decoding may be used. One or more intra block copy (IBC) block vectors may be determined. The one or more IBC block vectors may be associated with a current coding block. The coding block may include multiple sub-partitions. For a sub-partition, the block vector may be refined based on a template associated with the sub-partition. The refinement may be performed using a refinement window. The current coding block may be encoded and/or decoded based on the refined block vector.

Description

INTRA SUB-PARTITIONS (ISP) COMBINATION WITH INTRA BLOCK COPY (IBC)

CROSS-REFERENCE TO RELATED APPLICATOINS

[0001] The application claims the benefit of European Patent Application Number 23306093.8, filed June 30, 2023, the contents of which are incorporated by reference in their entirety herein.

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 encoding may be used. One or more intra block copy (IBC) block vectors may be determined. The one or more IBC block vectors may be associated with a current coding block. The coding block may include multiple subpartitions. For a sub-partition, the block vector may be refined based on a template associated with the sub-partition. The refinement may be performed using a refinement window. The current coding block may be encoded based on the refined block vectors associated with the sub-partitions.

[0004] Systems, methods, and instrumentalities are disclosed for performing video decoding may be used. One or more IBC block vectors may be determined. The one or more IBC block vectors may be associated with a current coding block. The coding block may include multiple sub-partitions. For a subpartition, the block vector may be refined based on a template associated with the sub-partition. The refinement may be performed using a refinement window. The current coding block may be decoded based on the refined block vectors associated with the sub-partitions.

[0005] 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. [0006] The device may include a video decoding device. The video decoding device may include a processor. The video decoding device may determine an intra block copy (IBC) block vector associated with a current coding block. For example, the video decoding device may perform a first template matching search. The IBC block vector associated with the current coding block may be determined based on the first template matching search. The current coding block may include a plurality (e.g., one or more) subpartitions. A (e.g., each) sub-partition from the plurality of sub-partitions may be a respective transform unit (TU). The video decoding device may refine IBC block vectors associated with a (e.g., each) sub-partition) of the plurality of sub-partitions to obtain a plurality of refined block vectors. The video decoding device may (e.g., to refine the IBC block vectors associated with each sub-partition of the plurality of sub-partitions to obtain a plurality of refined block vectors) refine the IBC block vector associated with the current coding block, for example, based on a first sub-partition from the plurality of sub-partitions to obtain a first refined IBC block vector associated with the first sub-partition. The video decoding device may (e.g., to refine the IBC block vectors associated with each sub-partition of the plurality of sub-partitions to obtain a plurality of refined block vectors) refine the IBC block vector associated with the current coding block based on a second sub-partition from the plurality of sub-partitions to obtain a second refined IBC block vector associated with the second sub-partition. The current coding block decoded based on the plurality of refined block vectors may be further based on the first refined IBC block vector associated with the first sub-partition and the second refined IBC block vector associated with the second sub-partition. The refinement of the IBC block vectors associated with each sub-partition of the plurality of sub-partitions to obtain a plurality of refined block vectors may include a determination of a first refined IBC block vector associated with a first sub-partition from the plurality of sub-partitions and a second refined IBC block vector associated with a second sub-partition from the plurality of sub-partitions. The video decoding device may perform a first template matching search based on a template associated with the first subpartition from the plurality of sub-partitions. The determined first refined IBC block vector may be further based on the first template matching search. The video decoding device may perform a second template matching search based on a template associated with the second sub-partition from the plurality of subpartitions. The second refined IBC block vector may be further based on the second template matching search. The video decoding device may decode the current coding block, for example, based on the plurality of refined block vectors. The video decoding device may determine to use a filter with IBC prediction associated with the current coding block. The video decoding device may (e.g., based on the determination to use a filter with IBC prediction associated with the current coding block) perform filtering on at least one of the plurality of sub-partitions. The filtering may be performed based on a determination of whether to perform filtering on each respective sub-partition from the plurality of sub-partitions. [0007] The device may include a video encoding device. The video encoding device may include a processor. The video encoding device may determine an intra block copy (IBC) block vector associated with a current coding block. For example, the video encoding device may perform a first template matching search. The IBC block vector associated with the current coding block may be determined based on the first template matching search. The current coding block may include a plurality (e.g., one or more) subpartitions. A (e.g., each) sub-partition from the plurality of sub-partitions may be a respective transform unit (TU). The video encoding device may refine IBC block vectors associated with a (e.g., each) sub-partition) of the plurality of sub-partitions to obtain a plurality of refined block vectors. The video encoding device may (e.g., to refine the IBC block vectors associated with each sub-partition of the plurality of sub-partitions to obtain a plurality of refined block vectors) refine the IBC block vector associated with the current coding block, for example, based on a first sub-partition from the plurality of sub-partitions to obtain a first refined IBC block vector associated with the first sub-partition. The video encoding device may (e.g., to refine the IBC block vectors associated with each sub-partition of the plurality of sub-partitions to obtain a plurality of refined block vectors) refine the IBC block vector associated with the current coding block based on a second sub-partition from the plurality of sub-partitions to obtain a second refined IBC block vector associated with the second sub-partition. The current coding block encoded based on the plurality of refined block vectors may be further based on the first refined IBC block vector associated with the first sub-partition and the second refined IBC block vector associated with the second sub-partition. The refinement of the IBC block vectors associated with each sub-partition of the plurality of sub-partitions to obtain a plurality of refined block vectors may include a determination of a first refined IBC block vector associated with a first sub-partition from the plurality of sub-partitions and a second refined IBC block vector associated with a second sub-partition from the plurality of sub-partitions. The video encoding device may perform a first template matching search based on a template associated with the first subpartition from the plurality of sub-partitions. The determined first refined IBC block vector may be further based on the first template matching search. The video encoding device may perform a second template matching search based on a template associated with the second sub-partition from the plurality of subpartitions. The second refined IBC block vector may be further based on the second template matching search. The video encoding device may encode the current coding block, for example, based on the plurality of refined block vectors. The video encoding device may determine to use a filter with IBC prediction associated with the current coding block. The video encoding device may (e.g., based on the determination to use a filter with IBC prediction associated with the current coding block) perform filtering on at least one of the plurality of sub-partitions. The filtering may be performed based on a determination of whether to perform filtering on each respective sub-partition from the plurality of sub-partitions. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] FIG. 1 A is a system diagram illustrating an example communications system in which one or more disclosed embodiments may be implemented.

[0009] FIG. 1 B is a system diagram illustrating an example wireless transmit/receive unit (WTRU) that may be used within the communications system illustrated in FIG. 1 A according to an embodiment.

[0010] FIG. 1 C is a system diagram illustrating an example radio access network (RAN) and an example core network (ON) that may be used within the communications system illustrated in FIG. 1A according to an embodiment.

[0011] FIG. 1 D is a system diagram illustrating a further example RAN and a further example ON that may be used within the communications system illustrated in FIG. 1 A according to an embodiment.

[0012] FIG. 2 illustrates an example video encoder.

[0013] FIG. 3 illustrates an example video decoder.

[0014] FIG. 4 illustrates an example of a system in which various aspects and examples may be implemented.

[0015] FIGs. 5A-B illustrates example sub-partitions, which may depend on block size.

[0016] FIG. 6 illustrates an example of padding candidates for the replacement of the zero-vector in the IBC list.

[0017] FIG. 7 illustrates an example of IBC candidate clustering which may be based on the L2 distance and the TM cost.

[0018] FIG. 8 illustrates an example IBC reference region, which may depend on a current coding unit (CU) position.

[0019] FIG. 9 illustrates an example reference area for coding tree unit (m, n).

[0020] FIG. 10 illustrates an example spatial part of a filter.

[0021] FIG. 11 illustrates an example IBC search per sub-partition.

[0022] FIG. 12 illustrates an example IBC merge mode with block vector difference (IBC-MBVD) mode.

DETAILED DESCRIPTION

[0023] A more detailed understanding may be had from the following description, given by way of example in conjunction with the accompanying drawings.

[0024] 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.

[0025] As shown in FIG. 1 A, the communications system 100 may include wireless transmit/receive units (WTRUs) 102a, 102b, 102c, 102d, a RAN 104/113, a ON 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 (loT) 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 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.

[0026] 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.

[0027] 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.

[0028] 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).

[0029] 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 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).

[0030] 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).

[0031] 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).

[0032] 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., an eNB and a gNB). [0033] 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, CDMA2000 1X, 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.

[0034] The base station 114b in FIG. 1 A 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.

[0035] 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 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.

[0036] 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.

[0037] 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.

[0038] FIG. 1 B is a system diagram illustrating an example WTRU 102. As shown in FIG. 1 B, 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.

[0039] 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 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. 1 B 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.

[0040] 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. [0041] Although the transmit/receive element 122 is depicted in FIG. 1 B 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.

[0042] 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.

[0043] 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 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).

[0044] 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.

[0045] 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 locationdetermination method while remaining consistent with an embodiment. [0046] 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.

[0047] 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)).

[0048] FIG. 1 C 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.

[0049] 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.

[0050] 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. 1 C, the eNode-Bs 160a, 160b, 160c may communicate with one another over an X2 interface. [0051] The CN 106 shown in FIG. 1 C 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.

[0052] 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.

[0053] 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.

[0054] 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.

[0055] 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.

[0056] Although the WTRU is described in FIGS. 1 A-1 D 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.

[0057] In representative embodiments, the other network 112 may be a WLAN.

[0058] 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 802.11 z tunneled DLS (TDLS). A WLAN using an Independent BSS (I BSS) 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.

[0059] When using the 802.11 ac 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 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.

[0060] 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.

[0061] 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).

[0062] Sub 1 GHz modes of operation are supported by 802.11af and 802.11 ah. The channel operating bandwidths, and carriers, are reduced in 802.11 af and 802.11 ah relative to those used in 802.11 n, and 802.11 ac. 802.11 af supports 5 MHz, 10 MHz and 20 MHz bandwidths in the TV White Space (TVWS) spectrum, and 802.11 ah supports 1 MHz, 2 MHz, 4 MHz, 8 MHz, and 16 MHz bandwidths using non- TVWS spectrum. According to a representative embodiment, 802.11 ah 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).

[0063] WLAN systems, which may support multiple channels, and channel bandwidths, such as

802.11 n, 802.11 ac, 802.11 af, and 802.11 ah, 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 802.11 ah, 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 entire available frequency bands may be considered busy even though a majority of the frequency bands remains idle and may be available.

[0064] In the United States, the available frequency bands, which may be used by 802.11 ah, 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

802.11 ah is 6 MHz to 26 MHz depending on the country code.

[0065] FIG. 1 D 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.

[0066] 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).

[0067] 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).

[0068] 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 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.

[0069] 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. 1 D, the gNBs 180a, 180b, 180c may communicate with one another over an Xn interface.

[0070] The CN 115 shown in FIG. 1 D 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.

[0071] 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. [0072] 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 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, Ethernetbased, and the like.

[0073] 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.

[0074] 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.

[0075] In view of Figures 1 A-1 D, and the corresponding description of Figures 1 A-1 D, 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.

[0076] 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.

[0077] 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 testing 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.

[0078] 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.

[0079] The aspects described and contemplated in this application may be implemented in many different forms. FIGS. 5-12 described herein may provide some examples, but other examples are contemplated. The discussion of FIGS. 5-12 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.

[0080] In the present application, the terms “reconstructed” and “decoded” may be used interchangeably, the terms “pixel” and “sample” may be used interchangeably, and the terms “image,” “picture” and “frame” may be used interchangeably.

[0081] 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.

[0082] 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.

[0083] Various numeric values are used in examples described by the present application, such as reconstructed sample values, etc. These and other specific values are for purposes of describing examples and the aspects described are not limited to these specific values.

[0084] FIG. 2 illustrates 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.

[0085] FIG. 2 illustrates an example of a block-based hybrid video encoder 200. 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 can be associated with the pre-processing, and attached to the bitstream. [0086] 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, CUs (Coding Units). 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.

[0087] 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 the 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.

[0088] 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 Filter) filtering to reduce encoding artifacts. The filtered image is stored in a reference picture buffer (280).

[0089] FIG. 3 illustrates 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.

[0090] In particular, the input of the decoder includes a video bitstream, which can 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 can 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). Note that, for a given picture, the contents of the reference picture buffer 380 on the decoder 300 side is identical to the contents of the reference picture buffer 280 on the encoder 200 side for the same picture.

[0091] 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.

[0092] FIG. 4A 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, 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.

[0093] 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 may 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 may 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 may 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. [0094] 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 may 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 may 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.

[0095] 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 may store one or more of various items during the performance of the processes described in this document. Such stored items may 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.

[0096] 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.

[0097] 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. 4A, include composite video.

[0098] 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 may 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 may 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.

[0099] The USB and/or HDMI terminals may 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.

[0100] 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.

[0101] The system 400 includes communication interface 450 that enables communication with other devices via communication channel 460. The communication interface 450 may include, but is not limited to, a transceiver configured to transmit and to receive data over communication channel 460. The communication interface 450 may 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. [0102] 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.

[0103] The system 400 may 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 may also be integrated with other components (for 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. [0104] 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.

[0105] The display 475 and speakers 485 may 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.

[0106] 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 may encompass one or more microprocessors, general purpose computers, special purpose computers, and processors based on a multi-core architecture, as non-limiting examples. [0107] Various implementations involve decoding. “Decoding,” as used in this application, may 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 application, for example, performing intra-sub partitioning, intra block copying, etc.

[0108] 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.

[0109] Various implementations involve encoding. In an analogous way to the above discussion about “decoding,” “encoding” as used in this application may 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, performing intra-sub partitioning, intra block copying, etc.

[0110] 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.

[0111] Note that syntax elements as used herein, for example, coding syntax on bi-predictive IBC samples, etc., are descriptive terms. As such, they do not preclude the use of other syntax element names. [0112] 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.

[0113] 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 may 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.

[0114] 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.

[0115] Additionally, this application may refer to “determining” various pieces of information. Determining the information may 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.

[0116] Further, this application may refer to “accessing” various pieces of information. Accessing the information may 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. [0117] 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 may 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.

[0118] It is to be appreciated that the use of any of the following 7”, “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.

[0119] Also, as used herein, the word “signal” refers to, among other things, indicating something to a corresponding decoder. Encoder signals may include, for example, an indication of a bi-predictive IBC (e.g., Bi_IBC_flag), an indication of a prediction mode, 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 may transmit (explicit signaling) a particular parameter to the decoder so that the decoder may use the same particular parameter. Conversely, if the decoder already has the particular 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” may also be used herein as a noun.

[0120] 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 may 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.

[0121] 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 devices may receive a signal including an encoded image, and perform decoding.

[0122] Intra sub-partitions (ISP) may be provided. ISP may split an intra block into multiple transform units that share the same CU information. For example, if intra block copy (IBC) may be enabled for ISP, one or more TUs (e.g., all TUs) would use the same CU information. For example, if IBC may be enabled for one or more, IBC block vectors may be shared.

[0123] Examples described herein may provide a method that enables per transform unit (TU) refinement of IBC parameters. For example, the parameters may be first calculated at CU level, and a refinement stage may be performed for a sub-partition (e.g., each sub- partition). This may lead to improved prediction with reasonable added complexity.

[0124] Intra sub-partitions (ISP) may be performed. For example, luma intra-predicted blocks may be divided vertically or horizontally into 2 or 4 sub-partitions depending on the block size. For example, a minimum block size for ISP may be 4x8 (or 8x4). If the block size is greater than 4x8 (or 8x4), then the corresponding block may be divided by 4 sub-partitions. The M*128 (with M<64) and 128*N (with N<64) ISP blocks may generate a potential issue with the 64x64 VDPU. In an example, an Mx128 CU in a single tree case may have an Mx128 luma TB and two corresponding M/2x64 chroma TBs. If the CU uses ISP, then the luma TB may be divided into four Mx32 TBs (e.g., only the horizontal split may be possible), and each of them may be smaller than a 64x64 block. In an example, the ISP chroma blocks may not be divided. Both chroma components may have a size greater than a 32x32 block. A similar situation may be created with a 128xN CU using ISP. These two examples (e.g., cases) may be an issue for the 64x64 decoder pipeline. For this reason, the CU sizes that may use ISP may be restricted to a maximum of 64x64. FIGs. 5A-B shows examples of the two possibilities. One or more sub-partitions (e.g., all subpartitions) may fulfill the condition of having at least 16 samples.

[0125] FIGs. 5A-B illustrates example sub-partitions, which may depend on block size. FIG. 5A illustrates an example sub-partitions for 4x8 and 8x4 CUs. FIG. 5B illustrates an example of sub-partitions for CUs other than 4x8, 8x4, and 4x4.

[0126] In ISP, the dependence of 1xN/2xN subblock prediction on the reconstructed values of previously decoded 1xN/2xN subblocks of the coding block may be not allowed so that the minimum width of prediction for subblocks may become four samples. For example, an 8xN (N > 4) coding block that may be coded using ISP with vertical split may be split into two prediction regions each of size 4xN, and four transforms of size 2xN. A 4xN coding block that may be coded using ISP with vertical split may be predicted using the full 4xN block; four transform each of 1xN may be used. Although the transform sizes of 1xN and 2xN are allowed, it may be asserted that the transform of these blocks in 4xN regions may be performed in parallel. For example, when a 4xN prediction region contains four 1xN transforms, there may be no transform in the horizontal direction; the transform in the vertical direction may be performed as a single 4xN transform in the vertical direction. Similarly, when a 4xN prediction region contains two 2xN transform blocks, the transform operation of the two 2xN blocks in each direction (horizontal and vertical) may be conducted in parallel. In an example, there is no delay added in processing these smaller blocks than processing 4x4 regular-coded intra blocks.

[0127] Table 1 shows example entropy coding coefficient group sizes.

Table 1

[0128] For a sub-partition (e.g., each sub-partition), reconstructed samples may be obtained by adding the residual signal to the prediction signal. A residual signal may be generated by the processes such as entropy decoding, inverse quantization, and inverse transform. The reconstructed sample values of a (e.g., each) sub-partition may be available to generate the prediction of the next sub-partition, and a (e.g., each) sub-partition may be processed repeatedly. The first sub-partition to be processed may be the one containing the top-left sample of the CU and then continuing downwards (horizontal split) or rightwards (vertical split). Reference samples used to generate the sub-partitions prediction signals may be located (e.g., only located) at the left and above sides of the lines. One or more (e.g., all) sub-partitions may share the same intra mode.

[0129] An ISP may interact with other coding tools in a number of ways. Multiple reference line (MRL) may interact with ISP. For example, if a block has an MRL index other than 0, then the ISP coding mode may be inferred to be 0, and ISP mode information may not be sent to the decoder.

[0130] Entropy coding coefficient group size may interact with ISP. The sizes of the entropy coding subblocks may have been modified so that they have 16 samples in one or more (e.g., all ) possible cases, as shown in Table 1. The sizes may (e.g., may only) affect blocks produced by ISP in which one of the dimensions may be less than 4 samples. In other cases, coefficient groups may keep the 4x4 dimensions. [0131] CBF coding may interact with ISP. At least one of the sub-partitions may have a non-zero CBF. If n is the number of sub-partitions and the first n - 1 sub-partitions have produced a zero CBF, then the CBF of the n-th sub-partition may be inferred to be 1.

[0132] Transform size restriction may interact with ISP. One or more ISP transforms with a length larger than the 16 points that may use the DCT-II .

[0133] MTS flag may interact with ISP. If a CU uses the ISP coding mode, the MTS CU flag may be set to 0 and it may not be sent to the decoder. The encoder may not perform RD tests for the different available transforms for a (e.g., each) resulting sub-partition. The transform choice for the ISP mode may instead be fixed and selected according to the intra mode, the processing order, and the block size utilized. In an example, no signaling may be required. For example, let t_H and t_v be the horizontal and the vertical transforms selected respectively for the w x h sub-partition, where w may be the width and h may be the height. The transform may be selected according to the following rules:

- If w = 1 or h = 1, then there may not be a horizontal or vertical transform respectively.

- If w > 4 and w < 16, t_H = DST-VII, otherwise, t_H = DCT-II

- If h > 4 and h < 16, t_v = DST-VII, otherwise, t_v = DCT-II

[0134] In an ISP mode, one or more of 67 intra modes (e.g., all 67 intra modes) may be allowed. PDPC may be applied if the corresponding width and height may be at least 4 samples long. The reference sample filtering process (e.g., reference smoothing) and the condition for intra interpolation filter selection may not exist anymore, and a Cubic (DCT-IF) filter may be (e.g., always) applied for fractional position interpolation in ISP mode.

[0135] IBC may be performed. IBC merge/AMVP list construction may be provided. An IBC merge/AMVP list construction may be performed based on one or more of the following: if (e.g., only if) an IBC merge/AMVP candidate is valid, it may be inserted into the IBC merge/AMVP candidate list; aboveright, bottom-left, and above-left spatial candidates, and one pairwise average candidate may be added into the IBC merge/AMVP candidate list; template-based adaptive reordering (ARMC-TM) may be applied to IBC merge list.

[0136] The HMVP table size for IBC may be increased to 25. After up to 20 IBC merge candidates are derived with full pruning, they may be reordered together. After reordering, the first 6 candidates with the lowest template matching costs may be selected as the final candidates in the IBC merge list.

[0137] The zero vectors’ candidates to pad the IBC Merge/AMVP list are 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, and it may be discarded as BVP in the IBC candidate list.

[0138] FIG. 6 illustrates example of padding candidates for the replacement of the zero-vector in the IBC list.

[0139] Three candidates may be located on the nearest corners of the reference region, and three additional candidates may be determined in the middle of the three sub-regions (A, B, and C), whose coordinates may be determined by the width, and height of the current block and the AX and AY parameters, as depicted in FIG. 6.

[0140] FIG.7 illustrates an example of IBC candidate clustering which may be based on the L2 distance and the TM cost. During the IBC AMVP list construction, a clustering of the BVP candidates may be applied when both BV candidate components are non-zero. The clustering, as shown in FIG. 7 with L2 distance, may be applied if there are more than two valid BV candidates and up to six candidates are clustered. The clustering radius may be defined as

Radius = og₂ (cbWidth - cbHeight) » MIN_PU_SIZE)

[0141] The clustering method may be applied in the candidate list order, and the candidates assigned to a group may be removed from the list for the subsequent clusters. In a group (e.g., each group), the BVP with the lowest TM cost may be selected as the representative candidate of that group. The representative candidates of the two first groups may be chosen as the candidates for the IBC AMVP list.

[0142] If one of BV candidate components may zero or a block may be coded in RRIBC, a flag may be signaled to indicate this case with a directional flag indicating a horizontal or vertical component is nonzero. Instead of the usual IBC AMVP list, two new BVP candidates may be derived, and the sign of the non-zero BV component may be derived at the decoder side. The AMVP BVP0 may be set to the nearest valid location to the current block (-cbWidth or -cbHeight), so the non-zero BVD may be negative (e.g., may always be negative), pointing to the left for a BV with a zero vertical component or to the above for a BV with a zero horizontal component. The AMVP BVP1 may be set to the farthest position from the current block in the valid reference region, which may be the left boundary or the top boundary of the IBC search region. If the BVP1 may be selected, the BVD may be positive (e.g., may always be positive), pointing to the right for BV with a zero vertical component or to the bottom for BV with a zero horizontal component. [0143] The optimal IBC AMVP index may be signaled, which may allow deriving the sign of the non-zero BVD component at the decoder side. The absolute magnitude of the non-zero BVD component may be further signaled. In RRIBC, the direction of the flipping mode may be derived from the signaled directional flag.

[0144] IBC with template matching may be performed. Template matching may be used in IBC for both IBC merge mode and IBC AMVP mode.

[0145] The IBC-TM merge list may be modified compared to the one used by regular IBC merge mode such that the candidates are selected according to a pruning method with a motion distance between the candidates as in a TM merge mode (e.g., a regular TM merge mode). The ending zero motion fulfillment may be replaced by motion vectors to the left (-W, 0), top (0, -H), and top-left (-W, -H), where W may be the width and H the height of the current CU.

[0146] In the IBC-TM merge mode, the selected candidates may be refined with template matching prior to the RDO or decoding process. In an example, the IBC-TM merge mode may be put in competition with the regular IBC merge mode, and a TM-merge flag may be signaled.

[0147] In the IBC-TM AMVP mode, up to three candidates may be selected from the IBC-TM merge list. A candidate (e.g., each candidate) of the three selected candidates may be refined using template matching method and sorted according to their resulting template matching cost. The first two (e.g., only the first two) may then be considered in the motion estimation process.

[0148] FIG. 8 illustrates an example IBC reference region, which may depend on a current CU position. The template matching refinement for both IBC-TM merge and AMVP modes may be simple as IBC motion vectors may be constrained (i) to be an integer and (ii) within a reference region as shown in FIG. 8. In IBC- TM merge mode, one or more (e.g., all) refinements may be performed at integer precision, and in IBC-TM AMVP mode, they may be performed either at integer or 4-pel precision depending on the AMVR value. For example, a refinement may access (e.g., only) to samples (e.g., without interpolation). In both cases, the refined motion vectors and the used template in a refinement process (e.g., each refinement process) may respect the constraint of the reference region.

[0149] IBC reference area may be provided. The reference area for IBC may be extended to two CTU rows. FIG. 9 illustrates an example reference area for coding CTU (m, n). For CTU (m, n) to be coded, the reference area may include CTUs with index (m-2, n-2)...(W, n— 2), (0, n-1)...(W, n— 1 ), (0, n)...(m, n), where W denotes the maximum horizontal index within the current tile, slice or picture. When a CTU size is 256, the reference area may be limited to one CTU row. This setting may ensure that for CTU size 128 or 256, IBC may not require extra memory. The per-sample block vector search (which may be referred to as a local search) range may be limited to [-(C « 1), C » 2] horizontally and [— C, C » 2] vertically to adapt to the reference area extension, where C denotes the CTU size.

[0150] FIG. 9 illustrates an example reference area for coding CTU (m, n). As shown in FIG. 9 depicts the current CTU, the reference area, and one or more invalid reference areas.

[0151] Filtered IBC may be performed. FIG. 10 illustrates an example spatial part of a filter. In an example, a 6-tap filter may include a 5-tap plus sign shape spatial component and a bias term. 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 and its above/north (N), below/south (S), left/west (W) and right/east (E) neighbors as illustrated below.

[0152] The bias term B may represent a scalar offset between the input and output and may be set to the middle luma value (512 for 10-bit content). The output of the filter may be calculated as follows: predLumaVal = cOC + clN + c2S + c3E + c4W + c5B

[0153] The filter coefficients ci may be calculated by minimizing the MSE between the reference template and a current template, which may be similar to a convolutional cross-component model (CCCM) process.

[0154] This filtered mode may be used as an additional mode for non-merge IBC blocks. For non-merge blocks, this mode may not be applied together with IBC-LIC, IBC-CIIP, or RR-IBC. For IBC merge modes. This filtering mode may be inherited when the merge mode list may be constructed, so there may not be extra signaling.

[0155] Bi-predictive IBC may be performed. In an example, a bi-predictive IBC may be used to enhance the coding performance of IBC for natural and screen content. In an example, an IBC may generate prediction samples with a (e.g., only) one BV (e.g., uni-predictive IBC), but it may still have room to improve the prediction accuracy of IBC. In an example, IBC may be added with two BVs (e.g., bi-predictive IBC), besides uni-predictive IBC.

[0156] In an example, a method may include two types of bi-predictive IBCs: Method 1 and Method 2. Method 1 , naming IBC BVP-merge mode, may derive the two BVs from IBC BVP mode and IBC merge mode, which may be similar to the MV derivation of AMVP-merge mode. Two different indices for the IBC BVP mode and the IBC merge candidate may be signaled from the encoder to the decoder, which may be different from the AMVP-merge mode.

[0157] Method 2, naming bi-predictive IBC merge mode, may derive the two BVs from the IBC merge candidate list, which may utilize two different IBC merge indices. The two may be signaled from the encoder to the decoder. The target of the bi-predictive IBC merge mode may be a (e.g., only) IBC-regular merge and may be an IBC merge mode with block vector difference (IBC-MBVD) and IBC geometric partitioning mode (IBC-GPM), which may be enabled for screen content by default. In Method 2, 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.

[0158] In an example, a method may comprise merge candidate list construction, BV refinement, compensation, BV storage, signaling, and/or the like. Merge candidate list construction may allow for Method 1 and/or Method 2 to reuse the existing IBC merge candidate list construction scheme for uni- predictive IBC merge mode. BV refinement may allow for Method 1 and/or Method 2 to enable the IBC with template matching. Compensation may allow for Method 1 and/or Method 2 to generate final IBC prediction samples with a (1 :1) average of bi-predictive IBC samples. BV storage may allow for Method 1 and/or Method 2 to store the two BVs in BV storage when the bi-predictive IBC s enabled. Signaling may allow for Method 1 and/or Method 2 to use a control flag of bi-predictive IBC, such as Bi_IBC_flag. Bi_IBC_flag may be signaled at a slice level in I slice, and may not be signaled in B and P slices. Reconstructed-Reordered IBC may be disabled when the bi-predictive IBC may be enabled. Method 1 and/or Method 2 may be enabled in chroma component blocks of the single tree.

[0159] Examples described herein may provide a method for refining IBC for a TU (e.g., each TU) in ISP mode to improve the prediction. Examples described herein may provide refinement of IBC search per subpartition.

[0160] FIG. 11 illustrates an example refinement of an IBC search per sub-partition. When ISP may be used and IBC may be enabled at CU level, one or more (e.g., all) sub-partitions may use IBC. At TU level, a refinement process may be performed, where the block vectors (BV’s) obtained from CU level template matching may be refined for a (e.g., each) sub-partition.

[0161] At a TU level, the obtained block vector(s) may be refined for a (e.g., each) sub-partition. For example the block vector (BV) at the i-th sub-partition, a refined block vector may be obtained by performing a template matching search around BV with a limited number of iterations. For example, a refinement window of size 4x4 may be considered. The template used for the refinement may be associated with the corresponding sub-partition. For example, the template used for refining a BV for a sub-partition may include template samples around the sub-partition (e.g., instead of the whole CU). In this case of bi-directional prediction (multiple BV’s), the refinement may be performed for a (e.g., each) subpartition and/or BV independently.

[0162] Examples described herein may provide filtering consideration. At a CU level, a flag may be signaled to indicate if filtering may be performed on IBC prediction. When an ISP may be used, there may be one or more possibilities for performing the filtering operation. In an example, filtering may be performed for one or more (e.g., all) sub-partitions. The CU level flag may be applied for the sub-partitions (e.g., all sub-partition) in the coding block. In an example, one or more sub-partitions may be selectively filtered. A sub-partition level indication may be signaled to indicate whether filtering is applied or not for a subpartition. For example, a TU level flag may be signaled to indicate whether or not the sub-partition uses a filtering operation or not. This may provide the encoder with some flexibility to check if the filtering improves the prediction for the current sub-partition. In an example, the filtering parameters may be calculated for a sub-partition (e.g., each sub-partition). For a sub-partition (e.g., each sub-partition), the filter parameters may be calculated (e.g., instead of calculating them once of the whole CU). This may lead to better capture of local statistics and may improve the overall prediction quality.

[0163] In an example case of Bi-directional prediction (multiple BV’s), the possibilities for performing the filtering operation may be performed for a (e.g., each) sub-partition and/or BV independently.

[0164] Merge with block vector difference (MBVD) may be used. A block vector coding mode called IBC-MBVD (IBC merge with block vector difference) may be used as a sub-mode of the IBC merge mode. A base merge candidate, taken from the first five candidates in the reordered IBC merge list, may be signaled, and a block offset to be applied on the base candidate may be signaled in video data.

[0165] In IBC-MBVD, the distance set (e.g., the set of possible BV offset magnitudes) may be {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}, and the BVD directions may be two horizontal and two vertical directions.

[0166] The base candidates may be selected from the first five candidates in the reordered IBC merge list. Based on a difference measure (e.g., sum of absolute differences (SAD) cost) between the template (one row above and one column left to the current block) and its reference for a refinement position (e.g., each refinement position), one or more (e.g., all) of the possible MBVD refinement positions (20*4) for a base candidate (e.g., each base candidate) are reordered. The top 8 refinement positions with the lowest template SAD costs may be kept as available positions for MBVD index coding. The MBVD index may be binarized by the rice code with the parameter equal to 1 .

[0167] FIG. 12 illustrates an example IBC-MBVD merge mode. The method may allow adaptive BVD offsets along MBVD directions. An MBVD list of K candidates with the lowest template SAD costs may be derived. At 1201 , denote the largest offset as N-pel, e.g. N=256, the number of directions D, e.g. D=4 (left, right, top, and bottom), the starting search interval M-pel, e.g. M=8, the number of candidates in MBVD list may be K, e.g. K=8. At 2, along a direction (e.g., each direction), check the TM SAD cost for an offset of every M-th position not exceeding N. The K lowest template matching (TM) SAD cost candidates may be kept on the list. At 1203, for a candidate (e.g., each candidate) in the list, check the TM SAD cost of the two candidates with the offset equal to -^M/2 along the direction. The K lowest TM SAD cost candidates may be kept on the list. At 1204, 1203 may be repeated, while reducing the interval M by half until it reaches 1- pel.

[0168] When an MBVD candidate has a left or above template outside of the BV search area, the MBVD candidate may be set to the invalid candidate. When two BVP candidates have the same BV component in a horizontal or vertical direction, the BV difference in the other direction has to be larger than a value, e.g., a threshold T, e.g. T = 8-pel. The MBVD index may be signaled in video data.

[0169] In an example, the IBC-MBVD merge mode may be used in camera-captured content, based on an MBVD candidate list construction. In an example, the IBC-MBVD block vector coding mode of IBC may be activated to compress camera-captured video contents. To do so, the MBVD block vector may be used when coding camera-captured video content, which may be referred to herein as natural videos.

[0170] In an example, when IBC may be used in combination with ISP, for a CU coded in IBC merge mode, one or more of the procedures that follow may be applied. In an example procedure, if the IBC- MBVD may be used for a given CU in IBC and ISP mode, then the MBVD candidate list may be derived at CU level, and a (e.g., a single) IBC-MBVD candidate may be selected and signaled for the whole CU. This may mean that the same BV may be used for one or more TUs (e.g., all TUs) in the IBC ISP block.

[0171] In an example procedure, some template matching-based refinement of the IBC-MBVD may be applied for a TU (e.g., each TU) in the considered CU. The best 8 candidate refinement positions may be computed on a TM-basis and may be repeated for a (e.g., each) TU. In an example procedure, the IBC merge list ordering may take place for a TU (e.g., each TU). In both example procedures, several different approaches may be possible for performing TU-level template matching search. In an example, the top and left template areas around a TU (e.g., each) may be used to refine the IBC-MBVD candidate block vectors. This may mean previous TUs of a given TU inside the CU may be reconstructed before processing the current TU. In an example, when a TU may be internal to the CU, the TU template top or left area located on the border of the CU may include a reconstructed neighboring sample, while the TU template area internal to the CU may include a predicted sample, leading to reduced latency in the IBC ISP block processing at the decoder side. In an example, when a TU may be the first of the CU coded in IBC/ISP mode, both left and above template areas of the TU may be used for template matching refinement of MBVD candidates. For TUs internal to the CU, the (e.g., only the) template area outside the considered CU may be used for TM-refinement of MBVD candidates.

[0172] In an example procedure, when TM-refinement of MBVD candidates happens at TU-level, a single MMVD index, identifying the base BV and BV offset of the current CU, may be signaled at CU-level. This may mean that the same MBVD index may be used for one or more TUs (e.g., all TUs), in combination with an MBVD candidate list that may vary from one TU to another one.

[0173] In an example procedure, the IBC/ISP mode may be used in combination with the MBVD candidate list computation as described herein. In an example approach, one or more (e.g., all) of the 4 procedures shown with respect to FIG. 12 may be repeated for a (e.g., each) TU. In an example approach, the iterative refinement part (e.g., only the iterative refinement part) may be applied at TU-level, e.g., at 3 and 4 of FIG. 12.

[0174] Examples described herein may provide Bi- or Uni-Prediction per TU. A bi-predictive IBC merge mode and BVP-merge mode may be used, where two merge indices on uni-predictive BV may be signaled. [0175] When ISP may be used in combination with one of these new modes, a sub-partition (e.g., each sub-partition) may use or not both BVs. As for filtering, one or more of the following procedures may be used. In an example, same number of BVs may be used for one or more (e.g., all) sub-partitions. The CU level flag may be applied for one or more sub-partition (e.g., all sub-partitions), and no further signaling may be required. In an example, the number of used BVs may be selectively signaled. A TU level flag may be signaled to indicate if the sub-partition uses both BVs or not. This may provide the encoder with some flexibility to check if the bi-predictive improves the prediction for the current sub-partition.

[0176] Systems, methods, and instrumentalities are disclosed for performing video encoding may be used. One or more intra block copy (IBC) block vectors may be determined. The one or more IBC block vectors may be associated with a current coding unit (CU). A block vector may be refined from the one or more IBC block vectors, wherein the block vector is associated with a sub-partition. The current coding block may be encoded based on the refined block vector.

[0177] In an example, a first template match search may be performed to determine the one or more IBC vectors. In an example, a second template match search may be performed around the block vector using a number of iterations to refine the block vector from the one or more IBC block vectors. In an example, a refinement window may be used to refine the block vector from the one or more IBC block vectors.

[0178] Systems, methods, and instrumentalities are disclosed for performing video decoding may be used. One or more intra block copy (IBC) block vectors may be determined. The one or more IBC block vectors may be associated with a current coding unit (CU). A block vector may be refined from the one or more IBC block vectors, wherein the block vector is associated with a sub-partition. The current coding block may be decoded based on the refined block vector. In an example, a first template match search may be performed to determine the one or more IBC vectors. In an example, a second template match search may be performed around the block vector using a number of iterations to refine the block vector from the one or more IBC block vectors. In an example, a refinement window may be used to refine the block vector from the one or more IBC block vectors.

[0179] Although features and elements are described above in particular combinations, one of ordinary skill in the art will appreciate that each feature or element may 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.

Claims

CLAIMS What is Claimed:

1 . A video decoding device, comprising: a processor configured to: determine an intra block copy (IBC) block vector associated with a current coding block, wherein the current coding block comprises a plurality of sub-partitions; refine IBC block vectors associated with each sub-partition of the plurality of sub-partitions to obtain a plurality of refined block vectors; and decode the current coding block based on the plurality of refined block vectors.

2. The video decoding device of claim 1 , wherein to refine the IBC block vectors associated with each sub-partition of the plurality of sub-partitions to obtain a plurality of refined block vectors, the processor is further configured to: refine the IBC block vector associated with the current coding block based on a first sub-partition from the plurality of sub-partitions to obtain a first refined IBC block vector associated with the first subpartition; and refine the IBC block vector associated with the current coding block based on a second subpartition from the plurality of sub-partitions to obtain a second refined IBC block vector associated with the second sub-partition, wherein the current coding block decoded based on the plurality of refined block vectors is further based on the first refined IBC block vector associated with the first sub-partition and the second refined IBC block vector associated with the second sub-partition.

3. The video decoding device of claim 1 , wherein each sub-partition from the plurality of sub-partitions is a respective transform unit.

4. The video decoding device of claim 1 , wherein the processor is further configured to: perform a first template matching search, wherein the IBC block vector associated with the current coding block is determined based on the performed first template matching search.

5. The video decoding device of claim 1 , wherein the refinement of the IBC block vectors associated with each sub-partition of the plurality of sub-partitions to obtain a plurality of refined block vectors comprises a determination of a first refined IBC block vector associated with a first sub-partition from the plurality of sub-partitions and a second refined IBC block vector associated with a second sub-partition from the plurality of sub-partitions, and wherein the processor is further configured to: perform a first template matching search based on a template associated with the first sub-partition from the plurality of sub-partitions, wherein the determined first refined IBC block vector is further based on the first template matching search; and perform a second template matching search based on a template associated with the second subpartition from the plurality of sub-partitions, wherein the determined second refined IBC block vector is further based on the second template matching search.

6. The video decoding device of claim 1 , wherein the processor is further configured to: determine to use a filter with IBC prediction associated with the current coding block; and based on the determination to use the filter with IBC prediction associated with the current coding block, perform filtering on at least one of the plurality of sub-partitions, wherein the filtering is performed based on a determination of whether to perform filtering on each respective sub-partition from the plurality of sub-partitions.

7. A video encoding device, comprising: a processor configured to: determine an intra block copy (IBC) block vector associated with a current coding block, wherein the current coding block comprises a plurality of sub-partitions; refine IBC block vectors associated with each sub-partition of the plurality of sub-partitions to obtain a plurality of refined block vectors; and encode the current coding block based on the plurality of refined block vectors.

8. The video encoding device of claim 7, wherein to refine the IBC block vectors associated with each sub-partition of the plurality of sub-partitions to obtain a plurality of refined block vectors, the processor is further configured to: refine the IBC block vector associated with the current coding block based on a first sub-partition from the plurality of sub-partitions to obtain a first refined IBC block vector associated with the first subpartition; and refine the IBC block vector associated with the current coding block based on a second subpartition from the plurality of sub-partitions to obtain a second refined IBC block vector associated with the second sub-partition, wherein the current coding block encoded based on the plurality of refined block vectors is further based on the first refined IBC block vector associated with the first sub-partition and the second refined IBC block vector associated with the second sub-partition.

9. The video encoding device of claim 7, wherein each sub-partition from the plurality of sub-partitions is a respective transform unit.

10. The video encoding device of claim 7, wherein the processor is further configured to: perform a first template matching search, wherein the IBC block vector associated with the current coding block is determined based on the performed first template matching search.

11 . The video encoding device of claim 7, wherein the refinement of the IBC block vectors associated with each sub-partition of the plurality of sub-partitions to obtain a plurality of refined block vectors comprises a determination of a first refined IBC block vector associated with a first sub-partition from the plurality of sub-partitions and a second refined IBC block vector associated with a second sub-partition from the plurality of sub-partitions, and wherein the processor is further configured to: perform a first template matching search based on a template associated with the first sub-partition from the plurality of sub-partitions, wherein the determined first refined IBC block vector is further based on the first template matching search; and perform a second template matching search based on a template associated with the second subpartition from the plurality of sub-partitions, wherein the determined second refined IBC block vector is further based on the second template matching search.

12. The video encoding device of claim 7, wherein the processor is further configured to: determine to use a filter with IBC prediction associated with the current coding block; and based on the determination to use the filter with IBC prediction associated with the current coding block, perform filtering on at least one of the plurality of sub-partitions, wherein the filtering is performed based on a determination of whether to perform filtering on each respective sub-partition from the plurality of sub-partitions.

13. A video decoding method, the video decoding method comprising: determining an intra block copy (IBC) block vector associated with a current coding block, wherein the current coding block comprises a plurality of sub-partitions; refining IBC block vectors associated with each sub-partition of the plurality of sub-partitions to obtain a plurality of refined block vectors; and decoding the current coding block based on the plurality of refined block vectors.

14. The video decoding method of claim 13, wherein to refine the IBC block vectors associated with each sub-partition of the plurality of sub-partitions to obtain a plurality of refined block vectors, the video decoding method further comprises: refining the IBC block vector associated with the current coding block based on a first sub-partition from the plurality of sub-partitions to obtain a first refined IBC block vector associated with the first subpartition; and refining the IBC block vector associated with the current coding block based on a second subpartition from the plurality of sub-partitions to obtain a second refined IBC block vector associated with the second sub-partition, wherein the current coding block decoded based on the plurality of refined block vectors is further based on the first refined IBC block vector associated with the first sub-partition and the second refined IBC block vector associated with the second sub-partition.

15. The video decoding method of claim 13, wherein each sub-partition from the plurality of subpartitions is a respective transform unit.

16. The video decoding method of claim 13, wherein the video decoding method further comprises: performing a first template matching search, wherein the IBC block vector associated with the current coding block is determined based on the performed first template matching search.

17. The video decoding method of claim 13, wherein the refinement of the IBC block vectors associated with each sub-partition of the plurality of sub-partitions to obtain a plurality of refined block vectors comprises a determination of a first refined IBC block vector associated with a first sub-partition from the plurality of sub-partitions and a second refined IBC block vector associated with a second subpartition from the plurality of sub-partitions, and wherein the video decoding method further comprises: performing a first template matching search based on a template associated with the first subpartition from the plurality of sub-partitions, wherein the determined first refined IBC block vector is further based on the first template matching search; and performing a second template matching search based on a template associated with the second sub-partition from the plurality of sub-partitions, wherein the determined second refined IBC block vector is further based on the second template matching search.

18. The video decoding method of claim 13, wherein the video decoding method further comprises: determining to use a filter with IBC prediction associated with the current coding block; and based on the determination to use the filter with IBC prediction associated with the current coding block, performing filtering on at least one of the plurality of sub-partitions, wherein the filtering is performed based on a determination of whether to perform filtering on each respective sub-partition from the plurality of sub-partitions.

19. A video encoding method, the video encoding method comprising: determining an intra block copy (IBC) block vector associated with a current coding block, wherein the current coding block comprises a plurality of sub-partitions; refining IBC block vectors associated with each sub-partition of the plurality of sub-partitions to obtain a plurality of refined block vectors; and encoding the current coding block based on the plurality of refined block vectors.

20. The video encoding method of claim 19, wherein to refine the IBC block vectors associated with each sub-partition of the plurality of sub-partitions to obtain a plurality of refined block vectors, the video encoding method further comprises: refining the IBC block vector associated with the current coding block based on a first sub-partition from the plurality of sub-partitions to obtain a first refined IBC block vector associated with the first subpartition; and refining the IBC block vector associated with the current coding block based on a second subpartition from the plurality of sub-partitions to obtain a second refined IBC block vector associated with the second sub-partition, wherein the current coding block encoded based on the plurality of refined block vectors is further based on the first refined IBC block vector associated with the first sub-partition and the second refined IBC block vector associated with the second sub-partition.

21 . The video encoding method of claim 19, wherein each sub-partition from the plurality of subpartitions is a respective transform unit.

22. The video encoding method of claim 19, wherein the video encoding method further comprises: performing a first template matching search, wherein the IBC block vector associated with the current coding block is determined based on the performed first template matching search.

23. The video encoding method of claim 19, wherein the refinement of the IBC block vectors associated with each sub-partition of the plurality of sub-partitions to obtain a plurality of refined block vectors comprises a determination of a first refined IBC block vector associated with a first sub-partition from the plurality of sub-partitions and a second refined IBC block vector associated with a second subpartition from the plurality of sub-partitions, and wherein the video encoding method further comprises: performing a first template matching search based on a template associated with the first sub- partition from the plurality of sub-partitions, wherein the determined first refined IBC block vector is further based on the first template matching search; and performing a second template matching search based on a template associated with the second sub-partition from the plurality of sub-partitions, wherein the determined second refined IBC block vector is further based on the second template matching search.

24. The video encoding method of claim 19, wherein the video encoding method further comprises: determining to use a filter with IBC prediction associated with the current coding block; and based on the determination to use the filter with IBC prediction associated with the current coding block, performing filtering on at least one of the plurality of sub-partitions, wherein the filtering is performed based on a determination of whether to perform filtering on each respective sub-partition from the plurality of sub-partitions.