Bi-predictive intra block copy with weighted averaging

Abstract

A device may determine, for a video block, a first prediction signal associated with intra block copy (IBC) bi-prediction and a second prediction signal associated with IBC bi-prediction, apply a first weighting factor to the first prediction signal to generate a first weighted prediction signal, determine a second weighting factor based on the first weighting factor, apply the second weighting factor to the second prediction signal to generate a second weighted prediction signal, and decode the video block based on the first weighted prediction signal and the second weighted prediction signal. The device may receive an indication of a weighting factor index and determine the weighting factor based on the received indication of the weighting factor index. In some examples, the device may the weighting factor from multiple weighting factors. For example, the device may select the weighting factor from a set of weighting factors based on template matching.

Description

BI-PREDICTIVE INTRA BLOCK COPY WITH WEIGHTED AVERAGINGCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of European Patent Application 23306081 .3, filed June 30, 2023, the disclosure of which is incorporated herein by reference in its entirety.BACKGROUND

[0002] Video coding systems may be used to compress digital video signals, e.g., to reduce the storage and / or transmission bandwidth needed for such signals. Video coding systems may include, for example, block-based, wavelet-based, and / or object-based systems.SUMMARY

[0003] Systems, methods, and instrumentalities are disclosed for a device configured to use weighted averaging of prediction signals for intra block copy (IBC) bi-prediction.

[0004] A device (e.g., a decoder) may determine, based on a block vector (BV), a first prediction block of a video block in a picture (e.g., the current picture) that includes the video block. The device may obtain a first weighting factor. The device may apply the first weighting factor to the first prediction block to generate a first weighted prediction block. The device may decode the video block based on the first weighted prediction block. For example, the BV may be associated with intra-block copy (IBC) bi-prediction. The BV may be associated with or a weighted intra template matching (IntraTMP) biprediction. In examples, the device may determine, for the video block, a second prediction block. The device may determine a second weighting factor. The second weighting factor may be different from the first weighting factor. The device may apply the second weighting factor to the second prediction block to generate a second weighted prediction block. The video block may be decoded, for example, further based on the second weighted prediction block. In examples, the device may store block vector prediction (BVP) candidate information associated with a BVP candidate. The BVP candidate information may include a value of a weighting factor. For example, the first weighting factor may be obtained based on the BVP candidate information.

[0005] In examples, the device may determine one or more template samples of a video block. The device may determine one or more reference template samples associated with a reference block of the video block based on the BV. The device may obtain the first weighting factor based on the one or more template samples of the video block and the one or more reference template samples associated with the reference block of the video block.

[0006] In examples, the device may receive an indication of a weighting factor index and / or determine the first weighting factor based on the received indication of the weighting factor index. In some examples, the device may receive an indication of the first weighting factor and / or determine the first weighting factor based on the received indication of the first weighting factor.

[0007] In examples, the device may obtain one or more weighting factors and / or select a weighting factor (e.g., the first weighting factor) from the one or more weighting factors based on template matching. The weighting factor may be associated with a minimum template cost compared to template costs associated with remaining weighting factors of the plurality of weighting factors. In some examples, the device may obtain the weighting factor based on a value (e.g., an absolute value) of a BV.

[0008] In examples, the device may obtain one or more weighting factors. The device may select a weighting factor from the one or more weighting factors based on rate distortion optimization (RDO). The weighting factor may be associated with a minimum RDO cost compared to RDO costs associated with remaining weighting factors of the one or more weighting factors.

[0009] In examples, a device (e.g., a decoder) may determine, for a video block, a prediction signal associated with intra block copy (IBC) bi-prediction, apply a weighting factor to the prediction signal to generate a weighted prediction signal, and decode the video block based on the weighted prediction signal. In the examples, IBC bi-prediction may be enabled for the video block. The device may obtain a block vector (BV) associated with IBC bi-prediction and use the BV to determine the prediction signal.

[0010] For example, the device may determine, for a video block, a first prediction signal associated with IBC bi-prediction and a second prediction signal associated with IBC bi-prediction, apply a first weighting factor to the first prediction signal to generate a first weighted prediction signal, determine a second weighting factor based on the first weighting factor, apply the second weighting factor to the second prediction signal to generate a second weighted prediction signal, and decode the video block based on the first weighted prediction signal and the second weighted prediction signal.

[0011] The device may receive an indication of the weighting factor and determine the weighting factor based on the received indication of the weighting factor. In examples, the device may receive an indication of a weighting factor index and determine the weighting factor based on the received indication of the weighting factor index.

[0012] The device may select the weighting factor from multiple weighting factors. For example, the device may obtain a set of weighting factors and select the weighting factor from the set of weighting factors based on template matching. The selected weighting factor may have a minimum template cost comparing to template costs associated with the other weighting factors of the set of weighting factors.In examples, the device may determine template samples of the video block and determine, based on a block vector associated with IBC bi-prediction, reference template samples associated with a reference block of the video block. The device may obtain the weighting factor based on the template samples of the video block and the reference template samples associated with the reference block of the video block.

[0013] A device (e.g., an encoder) may determine, based on a BV, a first prediction block of a video block in a picture (e.g., the current picture) that includes the video block. The device may obtain a first weighting factor. The device may apply the first weighting factor to the first prediction block to generate a first weighted prediction block. The device may encode the video block based on the first weighted prediction block. For example, the BV may be associated with intra-block copy (IBC) bi-prediction. The BV may be associated with or a weighted intra template matching (IntraTMP) bi-prediction. In examples, the device may determine, for the video block, a second prediction block. The device may determine a second weighting factor. The second weighting factor may be different from the first weighting factor. The device may apply the second weighting factor to the second prediction block to generate a second weighted prediction block. The video block may be encoded, for example, further based on the second weighted prediction block. In examples, the device may store block vector prediction (BVP) candidate information associated with a BVP candidate. The BVP candidate information may include a value of a weighting factor. For example, the first weighting factor may be obtained based on the BVP candidate information.

[0014] In examples, the device may determine one or more template samples of a video block. The device may determine one or more reference template samples associated with a reference block of the video block based on the BV. The device may obtain the first weighting factor based on the one or more template samples of the video block and the one or more reference template samples associated with the reference block of the video block.

[0015] In examples, the device may determine the first weighting factor and / or send an indication of a weighting factor index indicating the first weighting factor. In some examples, the device may determine the first weighting factor and / or send an indication of the first weighting factor.

[0016] In examples, the device may obtain one or more weighting factors and / or select a weighting factor (e.g., the first weighting factor) from the one or more weighting factors based on template matching. The weighting factor may be associated with a minimum template cost compared to template costs associated with remaining weighting factors of the plurality of weighting factors. In some examples, the device may obtain the weighting factor based on a value (e.g., an absolute value) of a BV.

[0017] In examples, the device may obtain one or more weighting factors. The device may select a weighting factor from the one or more weighting factors based on rate distortion optimization (RDO). The weighting factor may be associated with a minimum RDO cost compared to RDO costs associated with remaining weighting factors of the one or more weighting factors.

[0018] In examples, a device (e.g., an encoder) may determine, for a video block, a prediction signal associated with intra block copy (IBC) bi-prediction, apply a weighting factor to the prediction signal to generate a weighted prediction signal, and encode the video block based on the weighted prediction signal. In the examples, IBC bi-prediction may be enabled for the video block. The device may obtain a block vector (BV) associated with IBC bi-prediction and use the BV to determine the prediction signal.

[0019] For example, the device may determine, for a video block, a first prediction signal associated with IBC bi-prediction and a second prediction signal associated with IBC bi-prediction, apply a first weighting factor to the first prediction signal to generate a first weighted prediction signal, determine a second weighting factor based on the first weighting factor, apply the second weighting factor to the second prediction signal to generate a second weighted prediction signal, and encode the video block based on the first weighted prediction signal and the second weighted prediction signal.

[0020] The device may select the weighting factor from multiple weighting factors. For example, the device may obtain a set of weighting factors and select the weighting factor from the set of weighting factors based on template matching. The selected weighting factor may have a minimum template cost compared to template costs associated with the other weighting factors of the set of weighting factors. In examples, the device may determine template samples of the video block and determine, based on a block vector associated with IBC bi-prediction, reference template samples associated with a reference block of the video block. The device may obtain the weighting factor based on the template samples of the video block and the reference template samples associated with the reference block of the video block. The device may obtain a set of weighting factors and select the weighting factor from the set of weighting factors based on rate distortion optimization (RDO). The selected weighting factor may have a minimum RDO cost compared to RDO costs associated with the other weighting factors of the set of weighting factors. The device may send an indication of the weighting factor, for example, to a decoder.

[0021] 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 computerprogram product may include instructions which, when the program is executed by one or more processors, may cause the one or more processors to carry out the methods described herein.BRIEF DESCRIPTION OF THE DRAWINGS

[0022] FIG. 1 A is a system diagram illustrating an example communications system in which one or more disclosed embodiments may be implemented.

[0023] 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.

[0024] 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.

[0025] 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. 1A according to an embodiment.

[0026] FIG. 2 illustrates an example video encoder.

[0027] FIG. 3 illustrates an example video decoder.

[0028] FIG. 4 illustrates an example of a system in which various aspects and examples may be implemented.

[0029] FIG. 5 illustrates examples of the reference region(s) of an IBC mode.

[0030] FIG. 6 illustrates examples of the reference area(s) for encoding and / or decoding CTU (m,n).

[0031] FIG. 7 illustrates an example showing locations of candidates.

[0032] FIG. 8 illustrates an example weighted averaging module.

[0033] FIG. 9 illustrates an example of how the weight or weight index associated with the minimumRDO cost may be selected for a bi-predictive IBC, for example, by an encoder.

[0034] FIG. 10 illustrates an example L-shape template used for obtaining a weight index.

[0035] FIG. 11 illustrates an example for selecting a weight index or weighting factor, for a bi- predictive IBC, based on TM cost(s).

[0036] FIG. 12 illustrates an example for obtaining a weight or weighting factor based on distances.

[0037] FIG. 13 illustrates an example for decoding a weight index and / or applying the weight index to generate a bi-predictive IBC prediction signal, for example, by a decoder.

[0038] FIG. 14 illustrates an example for selecting a weight index or weighting factor, for a bi- predictive IBC, based on TM cost(s).DETAILED DESCRIPTION

[0039] A more detailed understanding may be had from the following description, given by way of example in conjunction with the accompanying drawings.

[0040] 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.

[0041] As shown in FIG. 1A, the communications system 100 may include wireless transmit / receive units (WTRUs) 102a, 102b, 102c, 102d, a RAN 104 / 113, a 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.

[0042] 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, aneNode 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.

[0043] 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.

[0044] 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).

[0045] 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).

[0046] 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 theair interface 116 using Long Term Evolution (LTE) and / or LTE-Advanced (LTE-A) and / or LTE- Advanced Pro (LTE-A Pro).

[0047] 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).

[0048] 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).

[0049] 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.

[0050] 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. 1 A, 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.

[0051] 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. 1 A, 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.

[0052] 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.

[0053] 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.

[0054] 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 subcombination of the foregoing elements while remaining consistent with an embodiment.

[0055] 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.

[0056] 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.

[0057] 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.

[0058] 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.

[0059] 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).

[0060] 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.

[0061] The processor 118 may also be coupled to the GPS chipset 136, which may be configured to provide location information (e.g., longitude and latitude) regarding the current location of the WTRU 102. In addition to, or in lieu of, the information from the GPS chipset 136, the WTRU 102 may receive location information over the air interface 116 from a base station (e.g., base stations 114a, 114b) and / or determine its location based on the timing of the signals being received from two or more nearby base stations. It will be appreciated that the WTRU 102 may acquire location information by way of any suitable location-determination method while remaining consistent with an embodiment.

[0062] 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.

[0063] 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)).

[0064] 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.

[0065] 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.

[0066] 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.

[0067] 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.

[0068] The MME 162 may be connected to each of the eNode-Bs 160a, 160b, 160c 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.

[0069] 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.

[0070] 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.

[0071] 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 PSTN108, 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.

[0072] 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.

[0073] In representative embodiments, the other network 112 may be a WLAN.

[0074] A WLAN in Infrastructure Basic Service Set (BSS) mode may have an Access Point (AP) for the BSS and one or more stations (STAs) associated with the AP. The AP may have an access or an interface to a Distribution System (DS) or another type of wired / wireless network that carries traffic in to and / or out of the BSS. Traffic to STAs that originates from outside the BSS may arrive through the AP and may be delivered to the STAs. Traffic originating from STAs to destinations outside the BSS may be sent to the AP to be delivered to respective destinations. Traffic between STAs within the BSS may be sent through the AP, for example, where the source STA may send traffic to the AP and the AP may deliver the traffic to the destination STA. The traffic between STAs within a BSS may be considered and / or referred to as peer-to-peer traffic. The peer-to-peer traffic may be sent between (e.g., directly between) the source and destination STAs with a direct link setup (DLS). In certain representative embodiments, the DLS may use an 802.11e DLS or an 802.11z tunneled DLS (TDLS). A WLAN using an Independent BSS (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.

[0075] 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.

[0076] 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.

[0077] 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).

[0078] Sub 1 GHz modes of operation are supported by 802.11 af 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).

[0079] WLAN systems, which may support multiple channels, and channel bandwidths, such as 802.11 n, 802.11ac, 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.

[0080] 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.

[0081] 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.

[0082] 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).

[0083] 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).

[0084] 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.

[0085] 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.

[0086] 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.

[0087] 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.

[0088] 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 N4interface. 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, Ethernet-based, and the like.

[0089] 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.

[0090] 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.

[0091] 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.

[0092] 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.

[0093] The one or more emulation devices may perform the one or more, including all, functions while not being implemented / deployed as part of a wired and / or wireless communication network. For example, the emulation devices may be utilized in a testing scenario in a testing laboratory and / or a non-deployed (e.g., testing) wired and / or wireless communication network in order to implement testing of one or more components. The one or more emulation devices may be test equipment. Direct RF coupling and / or wireless communications via RF circuitry (e.g., which may include one or more antennas) may be used by the emulation devices to transmit and / or receive data.

[0094] 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.

[0095] The aspects described and contemplated in this application may be implemented in many different forms. FIGS. 5-14 described herein may provide some examples, but other examples are contemplated. The discussion of FIGS. 5-14 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.

[0096] In the present application, the terms “reconstructed” and “decoded” may be used interchangeably, the terms “pixel” and “sample” may be used interchangeably, the terms “image,” “picture” and “frame” may be used interchangeably.

[0097] 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.

[0098] Various methods and other aspects described in this application may be used to modify modules, for example, decoding modules, of a video encoder 200 shown in FIG. 2 and a video decoder 300 as 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 preexisting 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.

[0099] Various numeric values are used in examples described the present application, for example, -1 / 4, 4 / 8, 0.906253, 2, 4, etc. These and other specific values are for purposes of describing examples and the aspects described are not necessarily limited to these specific values.

[0100] FIG. 2 is a diagram showing an example video encoder. Variations of example encoder 200 are contemplated, but the encoder 200 is described below for purposes of clarity without describing all expected variations.

[0101] Before being encoded, the video sequence may go through pre-encoding processing (201), for example, applying a color transform to the input color picture (e.g., conversion from RGB 4:4:4 to YCbCr 4:2:0), or performing a remapping of the input picture components in order to get a signal distribution more resilient to compression (for instance using a histogram equalization of one of the color components). Metadata may be associated with the pre-processing, and attached to the bitstream.

[0102] In the encoder 200, a picture is encoded by the encoder elements as described below. The picture to be encoded is partitioned (202) and processed in units of, for example, coding units (CUs). Each unit is encoded using, for example, either an intra or inter mode. When a unit is encoded in an intra mode, it performs intra prediction (260). In an inter mode, motion estimation (275) and compensation (270) are performed. The encoder decides (205) which one of the intra mode or inter mode to use for encoding the unit, and indicates the intra / inter decision by, for example, a prediction mode flag. Prediction residuals are calculated, for example, by subtracting (210) the predicted block from the original image block.

[0103] The prediction residuals are then transformed (225) and quantized (230). The quantized transform coefficients, as well as motion vectors and other syntax elements, are entropy coded (245) to output a bitstream. The encoder can skip the transform and apply quantization directly to the nontransformed 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.

[0104] 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 decodeprediction 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) filtering to reduce encoding artifacts. The filtered image is stored at a reference picture buffer (280).

[0105] FIG. 3 is a diagram showing an example of a video decoder. In example decoder 300, a bitstream is decoded by the decoder elements as described below. Video decoder 300 generally performs a decoding pass reciprocal to the encoding pass as described in FIG. 2. The encoder 200 also generally performs video decoding as part of encoding video data.

[0106] In particular, the input of the decoder includes a video bitstream, which may be generated by video encoder 200. The bitstream is first entropy decoded (330) to obtain transform coefficients, motion vectors, and other coded information. The picture partition information indicates how the picture is partitioned. The decoder may therefore divide (335) the picture according to the decoded picture partitioning information. The transform coefficients are de-quantized (340) and inverse transformed (350) to decode the prediction residuals. Combining (355) the decoded prediction residuals and the predicted block, an image block is reconstructed. The predicted block may be obtained (370) from intra prediction (360) or motion-compensated prediction (i.e., inter prediction) (375). In-loop filters (365) are applied to the reconstructed image. The filtered image is stored at a reference picture buffer (380).

[0107] 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.

[0108] An example context adaptive binary arithmetic coder (e.g., encoder and / or decoder) with dynamic model switch and / or parametrization may be used.

[0109] FIG. 4 is a diagram showing an example of a system in which various aspects and examples described herein may be implemented. System 400 may be embodied as a device including the various components described below and is configured to perform one or more of the aspects described in this document. Examples of such devices, include, but are not limited to, various electronic devices such as personal computers, laptop computers, smartphones, tablet computers, digital multimedia set top boxes, 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, inat 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.

[0110] The system 400 includes at least one processor 410 configured to execute instructions loaded therein for implementing, for example, the various aspects described in this document. Processor 410 can include embedded memory, input output interface, and various other circuitries as known in the art. The system 400 includes at least one memory 420 (e.g., a volatile memory device, and / or a non-volatile memory device). System 400 includes a storage device 440, which can include non-volatile memory and / or volatile memory, including, but not limited to, Electrically Erasable Programmable Read-Only Memory (EEPROM), Read-Only Memory (ROM), Programmable Read-Only Memory (PROM), Random Access Memory (RAM), Dynamic Random Access Memory (DRAM), Static Random Access Memory (SRAM), flash, magnetic disk drive, and / or optical disk drive. The storage device 440 can include an internal storage device, an attached storage device (including detachable and non-detachable storage devices), and / or a network accessible storage device, as non-limiting examples.

[0111] System 400 includes an encoder / decoder module 430 configured, for example, to process data to provide an encoded video or decoded video, and the encoder / decoder module 430 can include its own processor and memory. The encoder / decoder module 430 represents module(s) that may be included in a device to perform the encoding and / or decoding functions. As is known, a device can include one or both of the encoding and decoding modules. Additionally, encoder / decoder module 430 may be implemented as a separate element of system 400 or may be incorporated within processor 410 as a combination of hardware and software as known to those skilled in the art.

[0112] Program code to be loaded onto processor 410 or encoder / decoder 430 to perform the various aspects described in this document may be stored in storage device 440 and subsequently loaded onto memory 420 for execution by processor 410. In accordance with various examples, one or more of processor 410, memory 420, storage device 440, and encoder / decoder module 430 can store one or more of various items during the performance of the processes described in this document.Such stored items can include, but are not limited to, the input video, the decoded video or portions of the decoded video, the bitstream, matrices, variables, and intermediate or final results from the processing of equations, formulas, operations, and operational logic.

[0113] 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 duringencoding 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.

[0114] The input to the elements of system 400 may be provided through various input devices as indicated in block 445. Such input devices include, but are not limited to, (i) a radio frequency (RF) portion that receives an RF signal transmitted, for example, over the air by a broadcaster, (ii) a Component (COMP) input terminal (or a set of COMP input terminals), (iii) a Universal Serial Bus (USB) input terminal, and / or (iv) a High Definition Multimedia Interface (HDMI) input terminal. Other examples, not shown in FIG. 4, include composite video.

[0115] 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 bandlimiting a signal to a band of frequencies), (ii) downconverting the selected signal, (iii) band-limiting again to a narrower band of frequencies to select (for example) a signal frequency band which may be referred to as a channel in certain examples, (iv) demodulating the downconverted and band-limited signal, (v) performing error correction, and / or (vi) demultiplexing to select the desired stream of data packets. The RF portion of various examples includes one or more elements to perform these functions, for example, frequency selectors, signal selectors, band-limiters, channel selectors, filters, downconverters, demodulators, error correctors, and demultiplexers. The RF portion can include a tuner that performs various of these functions, including, for example, downconverting the received signal to a lower frequency (for example, an intermediate frequency or a near-baseband frequency) or to baseband. In one set-top box example, the RF portion and its associated input processing element receives an RF signal transmitted over a wired (for example, cable) medium, and performs frequency selection by filtering, downconverting, and filtering again to a desired frequency band. Various examples rearrange the order of the above-described (and other) elements, remove some of these elements, and / or add other elements performing similar or different functions. Adding elements can include inserting elements in between existing elements, such as, for example, inserting amplifiers and an analog-to-digital converter. In various examples, the RF portion includes an antenna.

[0116] The USB and / or HDMI terminals can include respective interface processors for connecting system 400 to other electronic devices across USB and / or HDMI connections. It is to be understoodthat 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.

[0117] 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 I nter-IC (I2C) bus, wiring, and printed circuit boards.

[0118] The system 400 includes communication interface 450 that enables communication with other devices via communication channel 460. The communication interface 450 can include, but is not limited to, a transceiver configured to transmit and to receive data over communication channel 460. The communication interface 450 can include, but is not limited to, a modem or network card and the communication channel 460 may be implemented, for example, within a wired and / or a wireless medium.

[0119] 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.

[0120] The system 400 can provide an output signal to various output devices, including a display 475, speakers 485, and other peripheral devices 495. The display 475 of various examples includes one or more of, for example, a touchscreen display, an organic light-emitting diode (OLED) display, a curved display, and / or a foldable display. The display 475 may be for a television, a tablet, a laptop, a cell phone (mobile phone), or other device. The display 475 can also be integrated with othercomponents (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.

[0121] 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.

[0122] The display 475 and speakers 485 can alternatively be separate from one or more of the other components, for example, if the RF portion of input 445 is part of a separate set-top box. In various examples in which the display 475 and speakers 485 are external components, the output signal may be provided via dedicated output connections, including, for example, HDMI ports, USB ports, or COMP outputs.

[0123] The examples may be carried out by computer software implemented by the processor 410 or by hardware, or by a combination of hardware and software. As a non-limiting example, the examples may be implemented by one or more integrated circuits. The memory 420 may be of any type appropriate to the technical environment and may be implemented using any appropriate data storage technology, such as optical memory devices, magnetic memory devices, semiconductor-based memory devices, fixed memory, and removable memory, as non-limiting examples. The processor 410 may be of any type appropriate to the technical environment, and can encompass one or more of microprocessors, general purpose computers, special purpose computers, and processors based on a multi-core architecture, as non-limiting examples.

[0124] Various implementations involve decoding. “Decoding”, as used in this application, can encompass all or part of the processes performed, for example, on a received encoded sequence in order to produce a final output suitable for display. In various examples, such processes include one or more of the processes typically performed by a decoder, for example, entropy decoding, inversequantization, 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, determining for a video block, a prediction signal associated with intra block copy (IBC) bi-prediction; applying a weighting factor to the prediction signal to generate a weighted prediction signal; and decoding the video block based on the weighted prediction signal etc.

[0125] 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.

[0126] Various implementations involve encoding. In an analogous way to the above discussion about “decoding”, “encoding” as used in this application can encompass all or part of the processes performed, for example, on an input video sequence in order to produce an encoded bitstream. In various examples, such processes include one or more of the processes typically performed by an encoder, for example, partitioning, differential encoding, transformation, quantization, and entropy encoding. In various examples, such processes also, or alternatively, include processes performed by an encoder of various implementations described in this application, for example, determining for a video block, a prediction signal associated with intra block copy (IBC) bi-prediction; applying a weighting factor to the prediction signal to generate a weighted prediction signal; and encoding the video block based on the weighted prediction signal etc.

[0127] 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.

[0128] Note that syntax elements as used herein, for example, Bi_IBC_flag, Bi_IBC_weight_index etc., are descriptive terms. As such, they do not preclude the use of other syntax element names.

[0129] 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.

[0130] 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 onlydiscussed in the context of a single form of implementation (for example, discussed only as a method), the implementation of features discussed can also be implemented in other forms (for example, an apparatus or program). An apparatus may be implemented in, for example, appropriate hardware, software, and firmware. The methods may be implemented in, for example, a processor, which refers to processing devices in general, including, for example, a computer, a microprocessor, an integrated circuit, or a programmable logic device. Processors also include communication devices, such as, for example, computers, cell phones, portable / personal digital assistants ("PDAs"), and other devices that facilitate communication of information between end-users.

[0131] 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.

[0132] Additionally, this application may refer to “determining” various pieces of information. Determining the information can include one or more of, for example, estimating the information, calculating the information, predicting the information, or retrieving the information from memory. Obtaining may include receiving, retrieving, constructing, generating, and / or determining.

[0133] Further, this application may refer to “accessing” various pieces of information. Accessing the information can include one or more of, for example, receiving the information, retrieving the information (for example, from memory), storing the information, moving the information, copying the information, calculating the information, determining the information, predicting the information, or estimating the information.

[0134] Additionally, this application may refer to “receiving” various pieces of information. Receiving is, as with “accessing”, intended to be a broad term. Receiving the information can include one or more of, for example, accessing the information, or retrieving the information (for example, from memory).Further, “receiving” is typically involved, in one way or another, during operations such as, for example, storing the information, processing the information, transmitting the information, moving the information, copying the information, erasing the information, calculating the information, determining the information, predicting the information, or estimating the information.

[0135] It is to be appreciated that the use of any of the following ”, “and / or”, and “at least one of’, for example, in the cases of “A / B”, “A and / or B” and “at least one of A and B”, is intended to encompass the selection of the first listed option (A) only, or the selection of the second listed option (B) only, or the selection of both options (A and B). As a further example, in the cases of “A, B, and / or C” and “at leastone 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.

[0136] Also, as used herein, the word “signal” refers to, among other things, indicating something to a corresponding decoder. Encoder signals may include, for example, Bi_IBC_weight_index, etc. In this way, in an example the same parameter is used at both the encoder side and the decoder side. Thus, for example, an encoder can transmit (explicit signaling) a particular parameter to the decoder so that the decoder can use the same particular parameter. Conversely, if the decoder already has the particular parameter as well as others, then signaling may be used without transmitting (implicit signaling) to simply allow the decoder to know and select the particular parameter. By avoiding transmission of any actual functions, a bit savings is realized in various examples. It is to be appreciated that signaling may be accomplished in a variety of ways. For example, one or more syntax elements, flags, and so forth are used to signal information to a corresponding decoder in various examples. While the preceding relates to the verb form of the word “signal”, the word “signal” can also be used herein as a noun.

[0137] As will be evident to one of ordinary skill in the art, implementations may produce a variety of signals formatted to carry information that may be, for example, stored or transmitted. The information can include, for example, instructions for performing a method, or data produced by one of the described implementations. For example, a signal may be formatted to carry the bitstream of a described example. Such a signal may be formatted, for example, as an electromagnetic wave (for example, using a radio frequency portion of spectrum) or as a baseband signal. The formatting may include, for example, encoding a data stream and modulating a carrier with the encoded data stream. The information that the signal carries may be, for example, analog or digital information. The signal may be transmitted over a variety of different wired or wireless links, as is known. The signal may be stored on, or accessed or received from, a processor-readable medium.

[0138] 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 todecode a bitstream, the encoder, bitstream, and / or decoder according to any of the embodiments described. For example, features described herein may be implemented by creating and / or transmitting and / or receiving and / or decoding a bitstream or signal. For example, features described herein may be implemented a method, process, apparatus, medium storing instructions, medium storing data, or signal. For example, features described herein may be implemented by a TV, set-top box, cell phone, tablet, or other electronic device that performs decoding. The TV, set-top box, cell phone, tablet, or other electronic device may display (e.g., using a monitor, screen, or other type of display) a resulting image (e.g., an image from residual reconstruction of the video bitstream). The TV, set-top box, cell phone, tablet, or other electronic device may receive a signal including an encoded image and perform decoding.

[0139] Systems, methods, and instrumentalities are disclosed for a device configured to use weighted averaging of prediction signals for intra block copy (IBC) bi-prediction.

[0140] A device (e.g., a decoder) may determine, based on a block vector (BV), a first prediction block of a video block in a picture (e.g., the current picture) that includes the video block. The device may obtain a first weighting factor. The device may apply the first weighting factor to the first prediction block to generate a first weighted prediction block. The device may decode the video block based on the first weighted prediction block. For example, the BV may be associated with intra-block copy (IBC) bi-prediction. The BV may be associated with or a weighted intra template matching (IntraTMP) biprediction. In examples, the device may determine, for the video block, a second prediction block. The device may determine a second weighting factor. The second weighting factor may be different from the first weighting factor. The device may apply the second weighting factor to the second prediction block to generate a second weighted prediction block. The video block may be decoded, for example, further based on the second weighted prediction block. In examples, the device may store block vector prediction (BVP) candidate information associated with a BVP candidate. The BVP candidate information may include a value of a weighting factor. For example, the first weighting factor may be obtained based on the BVP candidate information.

[0141] In examples, the device may determine one or more template samples of a video block. The device may determine one or more reference template samples associated with a reference block of the video block based on the BV. The device may obtain the first weighting factor based on the one or more template samples of the video block and the one or more reference template samples associated with the reference block of the video block.

[0142] In examples, the device may receive an indication of a weighting factor index and / or determine the first weighting factor based on the received indication of the weighting factor index. Insome examples, the device may receive an indication of the first weighting factor and / or determine the first weighting factor based on the received indication of the first weighting factor.

[0143] In examples, the device may obtain one or more weighting factors and / or select a weighting factor (e.g., the first weighting factor) from the one or more weighting factors based on template matching. The weighting factor may be associated with a minimum template cost compared to template costs associated with remaining weighting factors of the plurality of weighting factors. In some examples, the device may obtain the weighting factor based on a value (e.g., an absolute value) of a BV.

[0144] In examples, the device may obtain one or more weighting factors. The device may select a weighting factor from the one or more weighting factors based on rate distortion optimization (RDO). The weighting factor may be associated with a minimum RDO cost compared to RDO costs associated with remaining weighting factors of the one or more weighting factors.

[0145] In examples, a device (e.g., a decoder) may determine, for a video block, a prediction signal associated with intra block copy (IBC) bi-prediction, apply a weighting factor to the prediction signal to generate a weighted prediction signal, and decode the video block based on the weighted prediction signal. In the examples, IBC bi-prediction may be enabled for the video block. The device may obtain a block vector (BV) associated with IBC bi-prediction and use the BV to determine the prediction signal.

[0146] For example, the device may determine, for a video block, a first prediction signal associated with IBC bi-prediction and a second prediction signal associated with IBC bi-prediction, apply a first weighting factor to the first prediction signal to generate a first weighted prediction signal, determine a second weighting factor based on the first weighting factor, apply the second weighting factor to the second prediction signal to generate a second weighted prediction signal, and decode the video block based on the first weighted prediction signal and the second weighted prediction signal.

[0147] The device may receive an indication of the weighting factor and determine the weighting factor based on the received indication of the weighting factor. In examples, the device may receive an indication of a weighting factor index and determine the weighting factor based on the received indication of the weighting factor index.

[0148] The device may select the weighting factor from multiple weighting factors. For example, the device may obtain a set of weighting factors and select the weighting factor from the set of weighting factors based on template matching. The selected weighting factor may have a minimum template cost comparing to template costs associated with the other weighting factors of the set of weighting factors. In examples, the device may determine template samples of the video block and determine, based on a block vector associated with IBC bi-prediction, reference template samples associated with a referenceblock of the video block. The device may obtain the weighting factor based on the template samples of the video block and the reference template samples associated with the reference block of the video block.

[0149] A device (e.g., an encoder) may determine, based on a BV, a first prediction block of a video block in a picture (e.g., the current picture) that includes the video block. The device may obtain a first weighting factor. The device may apply the first weighting factor to the first prediction block to generate a first weighted prediction block. The device may encode the video block based on the first weighted prediction block. For example, the BV may be associated with intra-block copy (IBC) bi-prediction. The BV may be associated with or a weighted intra template matching (IntraTMP) bi-prediction. In examples, the device may determine, for the video block, a second prediction block. The device may determine a second weighting factor. The second weighting factor may be different from the first weighting factor. The device may apply the second weighting factor to the second prediction block to generate a second weighted prediction block. The video block may be encoded, for example, further based on the second weighted prediction block. In examples, the device may store block vector prediction (BVP) candidate information associated with a BVP candidate. The BVP candidate information may include a value of a weighting factor. For example, the first weighting factor may be obtained based on the BVP candidate information.

[0150] In examples, the device may determine one or more template samples of a video block. The device may determine one or more reference template samples associated with a reference block of the video block based on the BV. The device may obtain the first weighting factor based on the one or more template samples of the video block and the one or more reference template samples associated with the reference block of the video block.

[0151] In examples, the device may determine the first weighting factor and / or send an indication of a weighting factor index indicating the first weighting factor. In some examples, the device may determine the first weighting factor and / or send an indication of the first weighting factor.

[0152] In examples, the device may obtain one or more weighting factors and / or select a weighting factor (e.g., the first weighting factor) from the one or more weighting factors based on template matching. The weighting factor may be associated with a minimum template cost compared to template costs associated with remaining weighting factors of the plurality of weighting factors. In some examples, the device may obtain the weighting factor based on a value (e.g., an absolute value) of a BV.

[0153] In examples, the device may obtain one or more weighting factors. The device may select a weighting factor from the one or more weighting factors based on rate distortion optimization (RDO).The weighting factor may be associated with a minimum RDO cost compared to RDO costs associated with remaining weighting factors of the one or more weighting factors.

[0154] In examples, a device (e.g., an encoder) may determine, for a video block, a prediction signal associated with intra block copy (IBC) bi-prediction, apply a weighting factor to the prediction signal to generate a weighted prediction signal, and encode the video block based on the weighted prediction signal. In the examples, IBC bi-prediction may be enabled for the video block. The device may obtain a block vector (BV) associated with IBC bi-prediction and use the BV to determine the prediction signal.

[0155] For example, the device may determine, for a video block, a first prediction signal associated with IBC bi-prediction and a second prediction signal associated with IBC bi-prediction, apply a first weighting factor to the first prediction signal to generate a first weighted prediction signal, determine a second weighting factor based on the first weighting factor, apply the second weighting factor to the second prediction signal to generate a second weighted prediction signal, and encode the video block based on the first weighted prediction signal and the second weighted prediction signal.

[0156] The device may select the weighting factor from multiple weighting factors. For example, the device may obtain a set of weighting factors and select the weighting factor from the set of weighting factors based on template matching. The selected weighting factor may have a minimum template cost compared to template costs associated with the other weighting factors of the set of weighting factors. In examples, the device may determine template samples of the video block and determine, based on a block vector associated with IBC bi-prediction, reference template samples associated with a reference block of the video block. The device may obtain the weighting factor based on the template samples of the video block and the reference template samples associated with the reference block of the video block. The device may obtain a set of weighting factors and select the weighting factor from the set of weighting factors based on rate distortion optimization (RDO). The selected weighting factor may have a minimum RDO cost compared to RDO costs associated with the other weighting factors of the set of weighting factors. The device may send an indication of the weighting factor, for example, to a decoder.

[0157] 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.

[0158] Intra block copy coding may be used in one or more examples herein.

[0159] Intra block copy (IBC) may be used as a tool for screen content coding (SCC). IBC may improve the coding efficiency of screen content materials. Block matching (BM) may be performed, for example, at the encoder, to find the optimal block vector (BV) (or motion vector) for a (e.g., each) CU (e.g., since IBC mode is implemented as a block level coding mode). A block vector may indicate the displacement from a current block to a reference block. The reference block may have already been reconstructed inside a current picture. The luma block vector of an IBC-coded CU may be, for example, in integer precision. The chroma block vector may, for example, round to integer precision. The IBC mode may switch between motion vector precisions (e.g., between 1 -pel and 4-pel motion vector precisions), for example, when combined with adaptive motion vector resolution (AMVR). In examples, an IBC-coded CU may be treated as the third prediction mode (e.g., in addition to or other than an intra or inter prediction mode). The IBC mode may be applicable to certain CUs (e.g., the CUs with both width and height smaller than or equal to 64 luma samples).

[0160] IBC mode may be signaled at a CU level, (e.g., with a flag). IBC mode may be signaled as IBC advanced motion vector prediction (AMVP) mode or IBC skip / merge mode in one or more examples herein. In examples, IBC mode may be signaled as IBC skip / merge mode, where a merge candidate index may be used to indicate which of the block vectors in a list from neighboring candidate IBC coded blocks is used to predict the current block. A merge list may include (e.g., consist of) spatial, history-based motion vector predictor (HMVP), and pairwise candidates. In some examples, IBC mode may be signaled as IBC AMVP mode, where a block vector difference may be coded (e.g., encoded or decoded) in a similar or same way as a motion vector difference. The block vector prediction approach may use multiple (e.g., two) candidates as predictors, which are selected from the merge list based on a minimum cost (e.g., if IBC coded). A default block vector may be used as a predictor, for example, if one or more of the candidates (e.g., neighbor(s)) are not available. An indication (e.g., a flag) may be signaled to indicate a block vector predictor index.

[0161] IBC reference region(s) may be used, for example, to limit memory consumption and / or decoder complexity. In examples, the IBC may allow (e.g., only) the reconstructed portion of a predefined area (e.g., including the region of a current coding tree unit (CTU) and some region(s) of the left CTU). FIG. 5 illustrates examples of the reference region(s) of an IBC mode. The block in FIG. 5 (e.g., each block in FIG. 5) represents a 64x64 luma sample unit.

[0162] Depending on the location of the current CU location within the current CTU, one or more of the following may apply.

[0163] If current block falls into the top-left 64x64 block of the current CTU, then in addition to the already reconstructed samples in the current CTU, the current block may also refer to the referencesamples in the bottom-right 64x64 blocks of the left CTU, using an IBC mode. The current block may also refer to the reference samples in the bottom-left 64x64 block of the left CTU and the reference samples in the top-right 64x64 block of the left CTU, using an IBC mode.

[0164] If current block falls into the top-right 64x64 block of the current CTU, then in addition to the already reconstructed samples in the current CTU, if luma location (0, 64) relative to the current CTU has not yet been reconstructed, the current block may also refer to the reference samples in the bottom-left 64x64 block and bottom-right 64x64 block of the left CTU, using an IBC mode; otherwise, the current block may also refer to reference samples in the bottom-right 64x64 block of the left CTU.

[0165] If current block falls into the bottom-left 64x64 block of the current CTU, then in addition to the already reconstructed samples in the current CTU, if luma location (64, 0) relative to the current CTU has not yet been reconstructed, the current block may also refer to the reference samples in the topright 64x64 block and bottom-right 64x64 block of the left CTU, using an IBC mode. Otherwise, the current block may also refer to the reference samples in the bottom-right 64x64 block of the left CTU, using an IBC mode.

[0166] If current block falls into the bottom-right 64x64 block of the current CTU, the current block may refer to (e.g., only refer to) the already reconstructed samples in the current CTU, using an IBC mode.

[0167] One or more examples (e.g., example restrictions) herein may allow the IBC mode to be implemented using local on-chip memor(ies) for hardware implementations.

[0168] In some examples, the reference region for IBC may be extended to two CTU rows above the CTU being processed by the encoder and / or the decoder. FIG. 6 illustrates examples of the reference area(s) for encoding and / or decoding CTU (m,n). For CTU (m,n) to be coded (e.g., encoded or decoded), the reference area(s) 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. The per-sample block vector search (or referred to as the local search) range may be limited to [-(C « 1), C » 2] horizontally and [— C, C » 2] vertically e.g., to adapt to the reference area extension, where C denotes the CTU size.

[0169] IBC merge / AMVP list(s) may be constructed for use in one or more examples herein.

[0170] In examples, IBC merge / AMVP list construction may be modified, as one or more of the following. An IBC merge / AMVP candidate may be inserted into the IBC merge / AMVP candidate list, if and / or only if the IBC merge / AMVP candidate is valid. One or more of above-right, bottom-left, and / or above-left spatial candidates and / or one pairwise average candidate may be added into the IBCmerge / AMVP candidate list. Template based adaptive reordering (e.g., adaptive re-ordering of merge candidates based on template (ARMC-TM)) may be applied to the IBC merge list.

[0171] The HMVP table size for IBC may be increased to 25 entries. After one or more IBC merge candidates (e.g., up to 20 IBC merge candidates) are derived with full pruning, they may be reordered together. After reordering, the first several (e.g., 6) candidates with the lowest template matching costs may be selected as the final candidates in the IBC merge list.

[0172] The candidates from zero vectors (e.g., the ones used to pad the IBC Merge / AMVP list) may be replaced with a set of block vector prediction (BVP) candidates located in the IBC reference region. In examples, a zero vector may be invalid as a block vector in IBC merge mode (e.g., consequently it is discarded as BVP in the IBC candidate list).

[0173] FIG. 7 illustrates an example showing locations of candidates. As depicted in FIG. 7, three candidates are located on the nearest corners of the reference region, and three additional candidates are determined in the middle of the three sub-regions (A, B, and C), whose coordinates may be determined by the width, and the height of the current block and the AX and AY parameters.

[0174] IBC may be used with template matching.

[0175] In some examples, template matching (TM) based motion search and / or refinement may be applied to IBC.

[0176] An IBC-TM merge mode may be used. An IBC-TM merge mode may involve a merge candidate list for BV prediction, different from the one used by a regular IBC merge mode. The candidates may be selected according to a pruning method with motion distance(s) between the candidates (e.g., as in the regular TM merge mode). The zero motion candidates may have been replaced by MVs, for example, at (-W, 0), (0, -H), (-W, -H).

[0177] In the IBC-TM merge mode, selected candidates may be refined with the template matching. An TM-merge indication (e.g., the TM-merge flag) may be signaled to indicate the template matching merge IBC mode.

[0178] In an IBC-TM AMVP mode, one or more (e.g., up to 3) candidates may be selected from the IBC-TM merge list. Those candidates (e.g., each of those candidates) may be refined (e.g., according to the usual template matching method) and may be sorted, for example, according to their resulting TM costs.

[0179] TM refinement, for example, when used for IBC, may be performed at integer pel precision, and, in an IBC-TM AMVP mode, it is performed at integer or 4-pel precision, for example, depending onthe AMVR value. The refinement may be done within the IBC reference area (e.g., the existing IBC reference area).

[0180] IBC may interact with other coding tools. The interaction(s) between IBC mode and other inter coding tools (e.g., one or more of pairwise merge candidate, HMVP, combined intra / inter prediction mode (CIIP), merge mode with motion vector difference (MMVD), and / or geometric partitioning mode (GPM)) may include one or more of the following.

[0181] IBC may be used with pairwise merge candidate(s) and / or HMVP. A new pairwise IBC merge candidate may be generated, for example, by averaging multiple (e.g., two) IBC merge candidates. For HMVP, IBC motion(s) may be inserted into the history buffer for future referencing.

[0182] IBC may not be used in combination with the following inter tool: affine motion.

[0183] In examples, IBC may be used in combination with one or more of CIIP, MMVD, and / or GPM.

[0184] IBC may not be allowed for chroma coding blocks when DUAL_TREE partition is used.

[0185] In examples, the current picture may not be included as one of the reference pictures in the reference picture list 0 for IBC prediction. The derivation process of motion vectors for IBC mode may exclude all neighboring blocks in inter mode and vice versa. One or more of the following IBC design aspects may be applied. IBC may use pairwise merge candidate and / or HMVP. For example, IBC may share a similar or same process as in regular MV merge including using pairwise merge candidate(s) and HMVP. IBC may disallow temporal motion vector predictor (TMVP) and zero vector(s) because they are invalid for an IBC mode. Separate HMVP buffer(s) (e.g., 5 candidates each) may be used for conventional MV and IBC. For deblocking in some examples, IBC may be handled as an inter mode. If the current block is coded using IBC prediction mode, AMVR may not use a quarter-pel nor half-pel (e.g., instead, AMVR may be signaled to only indicate whether MV is inter-pel or 4 integer-pel). The number of IBC merge candidates may be signaled in a slice header separately from the numbers of regular, subblock, and geometric merge candidates.

[0186] Bi-predictive IBC may be used in one or more examples herein. In examples, a bi-predictive IBC may be used, for example, to enhance the coding performance of IBC for natural and screen content. Multiple (e.g., two) BVs may be used for IBC (e.g., bi-predictive IBC may be used in addition to uni-predictive IBC). The prediction accuracy of IBC may be improved.

[0187] In some examples (e.g., current ECM examples), IBC may generate prediction samples with one BV (e.g., only one BV used for uni-predictive IBC).

[0188] One or more of the following types of bi-predictive IBCs may be used: IBC BVP-merge mode; bi-predictive IBC merge mode.

[0189] For IBC BVP-merge mode, multiple BVs (e.g., two required BVs) may be derived from IBC BVP mode and IBC merge mode (e.g., similar to the MV derivation of AMVP-merge mode). Multiple (e.g., two) different indices for the IBC BVP mode and the IBC merge mode candidate may be signaled (e.g., from the encoder to the decoder), which may be different from the AMVP-merge mode.

[0190] For bi-predictive IBC merge mode, multiple BVs (e.g., two required BVs) may be derived from the IBC merge candidate list, utilizing multiple (e.g., two) different IBC merge indices. The indices may be signaled (e.g., from the encoder to the decoder). The target of the bi-predictive IBC merge mode may include I BC-regular merge, IBC merge mode with block vector difference (IBC-MBVD), and IBC geometric partitioning mode (IBC-GPM), which may be enabled, in examples, for screen content by default. Bi-predictive IBC-MBVD may be enabled in natural and screen content, and bi-predictive IBC- GPM may be enabled only in screen content.

[0191] One or more of the following may be used for bi-predictive IBC (e.g., IBC BVP-merge mode and / or bi-predictive IBC merge mode). Merge candidate list construction may be performed. The IBC merge candidate list construction scheme for uni-predictive IBC merge mode may be used (e.g., IBC BVP-merge mode and / or bi-predictive IBC merge mode may reuse the IBC merge candidate list construction scheme for uni-predictive IBC merge mode). BV refinement may be performed (e.g., IBC BVP-merge mode and / or bi-predictive IBC merge mode may enable IBC with template matching). Compensation may be performed (e.g., IBC BVP-merge mode and / or bi-predictive IBC merge mode may generate final IBC prediction samples with a simple (1 :1) average of bi-predictive IBC samples). BV storage may be used (e.g., the two BVs may be stored in BV storage when bi-predictive IBC is enabled). A control indication may be signaled (e.g., a control flag of bi-predictive IBC Bi JBC_flag may be signaled at a slice level in I slice, whereas not signaled in B and P slices; reconstructed-reordered IBC may be disabled when bi-predictive IBC is enabled). IBC BVP-merge mode and / or bi-predictive IBC merge mode may be enabled, for example, in chroma component blocks of the single tree.

[0192] Bi-prediction with CU-level weight (BCW) may be performed in some examples. In examples, a bi-prediction signal may be generated, for example, by averaging two prediction signals obtained from two different reference pictures and / or using two different motion vectors. In some examples, a biprediction mode may be extended beyond simple averaging to allow weighted averaging of the two prediction signals (e.g., BCW), e.g., as shown in Equation (1).Pbi-pred = ((8 - w) * Po+ W * Pi + 4) » 3 (1)

[0193] Multiple weights (e.g., five weights, w e {-2, 3, 4, 5, 10}) may be allowed in the weighted averaging bi-prediction. For a (e.g., each) bi-predicted CU, the weight w may be determined using one or more of the following: for a non-merge CU, the weight index may be signaled after the motion vectordifference; for a merge CU, the weight index may be inferred from neighboring blocks, for example, based on a merge candidate index. BCW may be applied (e.g., only applied) to CUs with 256 or more luma samples (e.g., CU(s) for which CU width times CU height is greater than or equal to 256). For low- delay pictures, the (e.g., all) 5 weights may be used. For non-low-delay pictures, 3 weights (e.g., only 3 weights we{3,4,5}) may be used.

[0194] Fast search algorithms may be applied at the encoder to find the weight index, for example, without significantly increasing the encoder complexity. One or more of the following algorithms may be used. When BCW is combined with AMVR, unequal weights may be conditionally checked (e.g., only conditionally checked) for 1 -pel and 4-pel motion vector precisions if the current picture is a low-delay picture.

[0195] When BCW is combined with an affine mode, affine motion estimation (ME) may be performed for unequal weights, for example, if and only if the affine mode is selected as the current best mode.

[0196] When the two reference pictures in bi-prediction are the same, unequal weights may be conditionally checked (e.g., only conditionally checked).

[0197] Unequal weights may not be searched when certain conditions are met, for example, depending on one or more of the POC distance between the current picture and its reference pictures, the coding quantization parameter (QP) (e.g., of the current block), or the temporal level (e.g., of the current picture).

[0198] The BCW weight index may be coded (e.g., encoded or decoded) using, for example, a context-coded bin followed by bypass-coded bins. The first context coded bin may indicate if equal weights are used; if unequal weights are used, additional bins may be signaled using bypass coding, for example, to indicate which unequal weight is used.

[0199] In some examples, CIIP and BCW may not be jointly applied for a CU. When a CU is coded with a CIIP mode, the BCW index of the current CU may be set to a certain value (e.g., 2 to indicate equal weights).

[0200] BCW index derivation for merge mode may be based on, for example, template matching.

[0201] In examples, BCW index for merge coded CUs may be derived based on template matching cost(s). When a merge candidate is determined for a merge CU according to the signaled merge candidate index, its BCW index may be derived based on TM cost(s). The TM cost for a (e.g., each) BCW index may be calculated using, for example, the sum of absolute differences (SAD) betweensamples of template(s) of neighboring reconstructed samples and corresponding reference samples, and the BCW index with the minimum TM cost may be used to code the merge CU.

[0202] One or more examples herein may be applied to a CU coded in one or more of regular merge, template matching, adaptive decoder-side motion vector refinement, or MMVD mode. When calculating TM cost(s) for bi-predicted weight(s), one or more the following may be applied. The bipredicted weights for a merge mode may be extended from {-2, 3, 4, 5, 10} to {1 , 2, 3, 4, 5, 6, 7}. The two neighboring bi-predicted weights and / or the inherited bi-predicted weight(s) (e.g., only the two neighboring bi-predicted weights (±1) and the inherited bi-predicted weight(s)) may be considered (e.g., since the inherited bi-predicted weight may have higher accuracy than others). For example, if the inherited bi-predicted weight is 4, three weights (e.g., only three weights {3, 4, 5}) may be used in TM cost calculation. The TM cost of the inherited BCW index may be multiplied with a value (e.g., 0.90625; the cost is reduced by 3 / 32) to favor the inherited BCW index. The TM cost of the equal weight may be multiplied with a value (e.g., a value such as 0.90625 since bi-predicted samples may be beneficial for BDOF and BDOF may be only applied to CU with equal weight).

[0203] In examples, a bi-predictive IBC may be used (e.g., to enhance the coding performance of IBC for natural and / or screen content). Bi-prediction IBC signal(s) may be generated, for example by simply averaging (1 :1) two prediction signals obtained from two different block vectors.

[0204] The bi-predictive IBC may be extended beyond averaging (e.g., simple averaging). In one or more examples herein, weighted averaging of multiple prediction signals (e.g., the two prediction signals obtained from two different block vectors) may be used, for example, to enhance the coding performance of IBC.

[0205] In one or more examples herein, bi-predictive IBC may provide for use of weighted averaging of multiple prediction signals (e.g., the two prediction signals obtained from two different block vectors), for example, to obtain the final IBC bi-prediction signal beyond simple averaging. Such weight(s) (or weighting factor(s)) may be determined per bi-predictive IBC CU, for example, from pre-defined set(s) or based on an online-derivation.

[0206] One or more of the following may be used or performed. Weight(s) may be determined based on one or more of rate-distortion optimization (RDO) cost(s), template matching (TM) cost(s), absolute value(s) of the block vector(s), or stored weight information in the candidate list(s). Weight(s) may be explicitly signaled or be implicitly derived.

[0207] Bi-predictive IBC with weighted averaging may be used in one or more examples herein. For example, bi-predictive IBC may be extended beyond simple averaging. Weighted averaging of multiple(e.g., two) prediction signals may be used to obtain an IBC bi-prediction signal (e.g., the final IBC biprediction signal).

[0208] For bi-predictive IBC, the prediction signal of a sample x as given by Equation (2) may be calculated from the weighted averaging of the two IBC prediction signals, for example, as follows:P [x] = w0* Po[x + v0] + w * P [x + v ] (2)

[0209] where P [x] denotes the resulting prediction signal of a sample x located at a picture position x; Pi [x + Vi] denotes the copied prediction signal of x using the block vector vtfor the i-th candidate; w0and w denote the two weight values shared across the samples in a block (e.g., all the samples in a block). Based on Equation (2), a variety of prediction signals may be obtained by adjusting the weight value, w0and w . Some configurations to w0and w may yield the same prediction as uni-predictive IBC and / or a certain type of bi-predictive IBC (e.g., bi-predictive IBC with equal weights). For example, (w0, wl)=(1, 0) may yield the same prediction as uni-prediction with a prediction candidate P0[x + v0]; (w0, w1)=(0, 1) may yield the same prediction as uni-prediction with another prediction candidate P [x + v- ; (w0, w1)=(0.5, 0.5) may yield the same prediction as bi-predictive IBC (e.g., one with equal weights) with two prediction candidates.

[0210] In some examples, weight(s) may be determined per bi-predictive IBC CU. A constraint where w0+W1= 1 may be applied, for example, to reduce the signaling overhead. For example, one weight (e.g., only one weight) may be signaled when the constraint where w0+ w = 1 is used. Equation (2) may become Equation (3).P[x] = (1 — w) * Po[x + v0] + w * Pt[x + v ] (3)

[0211] w may be discretized (e.g. {-1 / 4, 1 / 4, 3 / 8, 1 / 2, 5 / 8, 3 / 4, 5 / 4}). A weight value (e.g., each weight value) may be indicated, for example, by an index value within a small range. For example, a syntax element for signaling a weight index associated with the bi-predictive IBC (e.g., Bi_IBC_weight_index) may be used to indicate the weight(s) to be used for the current bi-predictive IBC. Signaling weight index for discretized weight(s) may reduce signaling overhead.

[0212] FIG. 8 illustrates an example weighted averaging module. As depicted in FIG. 8, the weighted averaging module for a bi-predictive IBC may use a two-step process to generate an IBC prediction signal (e.g., a final IBC prediction signal). The weighted averaging module for a bi-predictive IBC may be included by an encoder. The selected weight index may be signaled in video data (e.g., in a bitstream). IBC may be performed for a picture including searching two optimal block vectors (BVs) pointing to two reference blocks, for example, shown as block matching in FIG. 8. A weight index (e.g., the optimal weight index) may be searched (e.g., to minimize the weighted bi-prediction error between the current video block and bi-predictive prediction, as shown in FIG. 8 as weight value estimation). TheIBC prediction signal (e.g., the final IBC prediction signal) may be determined (e.g., computed) as a weighted average of multiple prediction signals (e.g., the two prediction blocks herein).

[0213] In examples, a set of allowed values of the weight w used for bi-predictive IBC and / or the number (e.g., nbweightin a set) of the allowed values of the weight w used for bi-predictive IBC may be pre-defined and / or fixed for the sequences (e.g., all sequences). A set of allowed values of the weight w used for bi-predictive IBC and / or the number of the allowed values of the weight w used for bi-predictive IBC nbweightin the set may be signaled in one or more of sequence parameter set (SPS), view parameter set (VPS), picture parameter set (PPS), adaptation parameter set (APS), or picture header (PH). In some examples, a set of allowed values of the weight w used for bi-predictive IBC and / or the number of the allowed values of the weight w used for bi-predictive IBC nbweigfltin the set may be dependent on one or more of: the QP for the current picture; color components for the current CU; transform types / cores / kernels associated with the current CU; slice type(s) associated with the current picture; or sequence class and configuration of the sequence associated with the current sequence. The weight values and / or the number of the weight values may be configuration-dependent. For example, for low-delay pictures, nbweight= 5 weights (e.g., {-1 / 4, 3 / 8, 1 / 2, 5 / 8, 5 / 4}, which may be all the nbweightweights) may be used; for non-low-delay pictures, nbweight= 3 weights (e.g., only 3 weights, for example, {3 / 8, 1 / 2, 5 / 8}) may be used.

[0214] In some examples, the weight w may be online-derived, for example, from the already encoded or decoded parameters of the current bi-predictive IBC block (e.g., the absolute value of the block vector(s)).

[0215] The weight(s) used for a bi-predictive IBC block (e.g., the weight w used for the current bi- predictive IBC block) may be determined according to one or more examples herein.

[0216] In examples, weight index derivation may be based on rate-distortion optimization (RDO) cost(s). The value of the weight w may be determined for bi-predictive IBC block(s) based on (RDO) cost(s). A weight w / weight index i (e.g., the best weight w / weight index i) associated with a minimum RDO cost may be selected among the (e.g., all) allowed weights in a pre-defined set.

[0217] FIG. 9 illustrates an example of how the weight or weight index associated with the minimum RDO cost may be selected for a bi-predictive IBC, for example, by an encoder. As shown in FIG. 9, the best weight index i may be selected for a bi-predictive IBC based on an RDO cost criterion. The bi- predictive IBC flag of an IBC-predicted block may be firstly checked (e.g., at 401 of FIG. 9). If bi- predictive IBC is not used for the current block, a uni-predictive IBC (e.g., a regular uni-predictive IBC) may be applied for the current block to generate the prediction samples using a BV (e.g., only one BV),for example, as shown at 402 of FIG. 9. If bi-predictive IBC is applied for the current block, multiple predictions for the current block may be generated with multiple BVs respectively (e.g., a first prediction signal Po for the current block may be generated using a first block vector vo, and a second prediction signal Pi for the current block may be generated using a second block vector vi shown at 403 of FIG. 8). For a weight (e.g., each weight associated with a respective weight index i = 0 ... nbweight, as shown at 404 of FIG. 9), the prediction samples for the current block may be generated by averaging the predictions based on the weight (e.g., averaging a first prediction signal Po and a second prediction signal Pi based on the weight as shown at 405 of FIG. 9; Equation (3) may be used at 405 of FIG. 9). After testing the (e.g., all) allowed weights, a weight index (e.g., the best weight index with minimum RDO cost) may be selected for generating the prediction samples (e.g., the final prediction samples) of the current block (as shown at 406 of FIG. 9).

[0218] Fast search algorithms may be applied to select the weight index, for example, to reduce encoder complexity. For example, when IBC is combined with AMVR (e.g., IBC-AMVR), unequal weights may be (e.g., only be) conditionally checked for integer-pel or 4 integer-pel block vector precisions if the current picture is a low-delay picture. Unequal weights may not be searched when certain conditions are met (e.g., depending on if IBC-CIIP or IBC-MMVD or IBC-GPM is used, and / or the coding QP).

[0219] Weight index derivation may be based on template matching. The value of the weight w may be obtained (e.g., derived) for bi-predictive IBC block(s) based on template matching (TM) cost(s). The TM cost associated with a (e.g., each) weight index i may be calculated, for example, using the SAD between samples of a template of the current block and corresponding weighted averaging reference samples of template(s) of the reference block(s). The weight index associated with the minimum TM cost may be used to code (e.g., decode or encode) a bi-predictive IBC CU.

[0220] FIG. 10 illustrates an example L-shape template used for obtaining a weight index. The reconstructed neighboring samples, in a left column and an above row, of the current block (e.g., the template T in FIG. 10), and their corresponding neighboring reconstructed samples in the current block’s reference blocks (e.g., the template Toand T in FIG. 10) are illustrated in FIG. 10.

[0221] The samples of the template(s) of the two reference blocks (e.g., reference block 0 and reference block 1 in FIG. 10) which are pointed by the two optimal BVs (e.g., BV0 and BV1 in FIG. 10), which may be blended with the weight wtindicated by the corresponding index i. The difference(s) between the weighted reference template samples and the current template samples may be calculated. The TM cost for a weight (e.g., each weight wf) may be formulated as Equation (4).

[0222] FIG. 11 illustrates an encoder example for selecting a weight index or weighting factor, for a bi-predictive IBC, based on TM cost(s). A weight index (e.g., the best weight index i) may be selected, for example, by an encoder, for a bi-predictive IBC based on TM cost criterion. The bi-predictive IBC flag of an IBC-predicted block may be firstly checked (e.g., at 501 of FIG. 11). If bi-predictive IBC is not used for the current block, a uni-predictive IBC (e.g., a regular uni-predictive IBC) may be applied for the current block to generate the prediction samples using a BV (e.g., only one BV), for example, as shown at 502 of FIG. 11 . If bi-predictive IBC is applied for the current block, the template samples (e.g., template samples T in FIG. 10) of the current block, first template samples (e.g., Toof FIG. 10) of a first reference block (e.g., reference block 0 of FIG. 10) pointed with a first BV (e.g., BV0 in FIG. 10 and / or vo in FIG. 11), and second template samples (e.g., T of FIG. 10) of a second reference block (e.g., reference block 1 of FIG. 10) pointed with a second BV (e.g., BV1 in FIG. 10 and / or vi in FIG. 11) may be obtained (e.g., at 503 of FIG. 11). For a weight (e.g., each weight associated with a respective weight index i = 0 ... nbweight, as shown at 504 of FIG. 11), the template samples of the reference blocks (e.g., Toof FIG. 10 and T of FIG. 10) may be averaged with this weight, and the difference from to the template samples (e.g., template samples T in FIG. 10) of the current block may be calculated (e.g., at 505 of FIG. 11). After testing the (e.g., all) allowed weights, a weight index (e.g., the best weight index associated with the minimum template cost as shown at 506 of FIG. 11) may be selected. Multiple (e.g., two) predictions for the current block may be generated with multiple BVs respectively (e.g., first prediction signal Po may be generated using the first BV vo;second prediction signal Pi may be generated using second BV vi as shown at 507 of FIG. 11). The prediction samples (e.g., the final prediction samples) for the current block may be generated, for example, by averaging these predictions with the selected weight (e.g., first prediction signal Po, the second prediction signal Pi , and the best weight associated with the minimum template cost, as shown at 508 of FIG. 11).

[0223] In examples, the template may include (e.g., be composed by) multiple left columns and / or multiple above rows. Left template or above template (e.g., only left template or above template) may be used for the TM cost calculation.

[0224] In some examples, the template may be the same template used for IBC-TM mode.

[0225] Weights (or weighting factors) derivation may be based on absolute value(s) of the block vector(s). The value of the weight w may be measured for bi-predictive IBC block(s), for example, based on the Euclidean distance from the current block to a reference block. The distance may bedetermined (e.g., induced), for example, by the absolute value of the block vector as shown in Equation (5).

[0226] where vixis the difference between x-coordinates of the current block and i-th reference block, and viyis the difference between y-coordinates.

[0227] FIG. 12 illustrates an example for obtaining a weight or weighting factor based on distances. The weight (e.g., the online-derived weight w) may be determined based on block vectors (e.g., by the ratio of the two optimal block vectors v0and vltwhich may be calculated as Equation (6)). For example, the weight may be determined by the ratio of distances associated with references blocks (e.g., reference block 0 in FIG. 12 and reference block 1 in FIG. 12) pointed by block vectors (e.g., reference block 0 pointed by the first optimal block vector v0and reference block 1 pointed by the second optimal block vectors v . The weight may be calculated as Equation (6).

[0228] where dQis the distance between the current block and its first reference block (e.g., reference block 0 in FIG. 12), and d is the distance between the current block and its second reference block (e.g., reference block 1 in FIG. 12), as illustrated in FIG. 12.

[0229] Weights (or weighting factors) derivation may be based on stored weight(s) in a candidate list. The value of the weight w may be stored as part of BVP candidates information and / or may be used for obtaining (e.g., deriving) the weight for one or more of the following bi-predictive IBC blocks. The weight index i may be stored in BVP information storage for the current bi-predictive IBC block. For a next bi- predictive IBC block, the weight w may be determined, for example, based on the mode of the bi- predictive IBC.

[0230] For an IBC block using bi-predictive IBC merge mode, its weight index i may be obtained (e.g., inferred) using one or more of the following: if only one predictor comes from a bi-predictive IBC block, the weight index i may be inferred from the weight index of this predictor; if both predictors come from bi-predictive IBC blocks, and they share the same weight index, the weight index i may be inferred from the same weight index of these two predictors; if both predictors come from bi-predictive IBC blocks, but they have different weight indexes, the weight may be inferred as the equal weight (e.g., 1 / 2), or the mean index may be used as the central index.

[0231] For an IBC block using bi-predictive BVP-merge mode, its weight index i may be obtained (e.g., derived) using one or more of the following: if only one predictor comes from a bi-predictive IBCblock, the weight index of this predictor and its + / -1 (e.g., only the weight index of this predictor and its + / -1) may be used for the weight index i derivation based on the RDO cost(s) or the TM cost(s); if both predictors come from bi-predictive IBC blocks, and they share the same weight index, the weight index i may be inferred from the same weight index of these two predictors, or this same weight index of these two predictors and its + / -1 (e.g., only this same weight index of these two predictors and its + / -1) may be used for the weight index i derivation based on the RDO cost(s) or the TM cost(s); if both predictors come from bi-predictive IBC blocks, but they have different weight indexes, these two weight indexes of the two predictors (and their + / -1) (e.g., only these two weight indexes of the two predictors (and their + / -1)) may be used for the weight index i derivation based on the RDO cost(s) or the TM cost(s), or all the possible weight indexes may still be tested for the weight index i derivation based on the RDO cost(s) or the TM cost(s).

[0232] The weight (or weighting factor) used for a bi-predictive IBC block may be signaled or determined (e.g., explicitly signaled or implicitly derived).

[0233] The signaling of the weight w used for the current bi-predictive IBC block may be based on explicit signaling, or implicit derivation.

[0234] The weight (or weighting factor) may be explicitly signaled. In examples, the weight w / weight index i used for a bi-predictive IBC block may be explicitly signaled.

[0235] FIG. 13 illustrates an example for decoding a weight index and / or applying the weight index to generate a bi-predictive IBC prediction signal, for example, by a decoder. A weight index and / or an indication of the weight index (e.g., Bi_IBC_weight_index) may be decoded (e.g., by a decoder) and applied for generating the bi-predictive IBC prediction signal. In examples, a weight index may be and / or an indication of the weight index (e.g., Bi_IBC_weight_index) may indicate the best weight index. The bi-predictive IBC flag (e.g., Bi JBC_flag) of an IBC-predicted block may be firstly parsed (e.g., at601 of FIG. 13), for example, to check if bi-predictive IBC is applied for the current block or not (e.g., at602 of FIG. 13). If bi-predictive IBC is not applied for the current block, a BV (e.g., only one BV) may be parsed and / or used for generating the prediction samples for the current block (e.g., at 603 of FIG. 13). If bi-predictive IBC is applied for the current block, multiple (e.g., two) BVs may be parsed and / or used for generating prediction samples (e.g., a first prediction signal Po of a first reference block for the current block may be generated using a first BV vo, and a second prediction signal Pi of a second reference block for the current block may be generated using a second BV vi, shown at 604 of FIG. 13). When Bi JBC_flag equals to TRUE, the weight index or the indication (e.g., the best weight index Bi_IBC_weight_index) may be parsed (e.g., parsed after these two BVs, the first BV vo and the second BV vi , as shown at 605 of FIG. 13). The prediction samples for this current block (e.g., the finalprediction samples for this current block) may be generated, for example, by averaging these predictions with the parsed weight (e.g., the first prediction signal Po, the second prediction signal Pi , and the best weight associated with Bi J BC_wei ght_i ndex, as shown at 606 of FIG. 13).

[0236] The weight index or the indication (e.g., best weight index Bi _IBC_weight_index) may be received and / or decoded from the video data (e.g., a bitstream), for example, by a decoder, and / or the weighted averaging bi-predictive IBC prediction samples or signal may be generated, for example, using Equation (3). For example, Equation (3) may be used to generate the prediction samples for the current block at 606 of FIG. 13.

[0237] If weight index derivation is based on template matching, the decoder procedure may be similar to or the same as an RDO cost based case, for example, similar to the example shown in FIG. 13, and the search of an weight or weight index may be based on template cost(s), for example, at the encoder. If weight derivation is based on absolute value(s) of the BV(s), a weight value may be decoded (e.g., the best weight value may be decoded directly instead of using the best weight index).

[0238] In examples, the weight index or the indication Bi_IBC_weight_index indicating weight value may be signaled based on truncated unary coding, as in the following tables, Table 1 and / or Table 2. Table 1 shows an example for binarization of index for 5 weights case. Table 2 shows an example for binarization of index for 3 weights case.Table 1Table 2

[0239] In examples, weight 4 / 8 may be considered the most frequently used weight and / or be signaled with the least number of bits (e.g., 1 bit).

[0240] A weight may be derived (e.g., implicitly). The weight w / weight index i used for a bi- predictive IBC may be implicitly derived, for example, to reduce the signaling overhead.

[0241] For example, if the weight index derivation is based on template matching, a search process for the weight index may be performed by a decoder, for example, based on template matching (e.g., the same search procedure may be performed in both the encoder and the decoder to find the best weight index Bi_IBC_weight_index). In some examples, a decoder may search for a weight index (e.g., the best weight index) in a manner similar to how an encoder (e.g., the encoder corresponding to the decoder) searches for the weight index.

[0242] FIG. 14 illustrates an example for selecting a weight index or weighting factor, for a bi- predictive IBC, based on TM cost(s) (e.g., FIG. 14 may show one or more features performed by an exemplary decoder; one or more features of FIG. 14 may be performed by an encoder in a template search procedure). For a (e.g., each) weight index candidate, the TM cost may be calculated using, for example, the SAD between samples of the template of the current block and corresponding weighted averaging reference samples of the template(s) of the reference block(s). A weight index (e.g., the best weight index Bi_IBC_weight_index, which has the minimum TM cost among all weight candidates) may be selected. A weighted averaging bi-predictive IBC prediction signal (e.g., the same weighted averaging bi-predictive IBC prediction signal as the one generated using Equation (3) at the encoder) may be generated, for example, at the decoder.

[0243] A weight index (e.g., the best weight index Bi _IBC_weight_index) may be selected, for example, by a decoder, for a bi-predictive IBC based on TM cost criterion. The bi-predictive IBC flag (e.g., BiJBCJag ) of an IBC-predicted block may be parsed (e.g., at 701 of FIG. 14). A determination may be made (e.g., at 702 of FIG. 14) on whether bi-predictive IBC is used for the current block, for example, based on the bi-predictive IBC flag. If bi-predictive IBC is not used for the current block (e.g., B / 'JBC_f7ag=FALSE , a BV (e.g., only one BV) may be parsed (e.g., as shown at 703 of FIG. 14) to generate the prediction samples for the current block, for example, using uni-predictive IBC. If bi- predictive IBC is used for the current block (e.g., B / _ / BC_f / ag=TRUE), multiple BVs (e.g., a first BV vo and a second BV vi) may be parsed (e.g., as shown at 704 of FIG. 14), and the BVs may be used to generate multiple prediction signals (e.g., first prediction signal Po may be generated using the first BV vo; second prediction signal Pi may be generated using second BV vi as shown at 704 of FIG. 14). The template samples (e.g., template samples T in FIG. 14) of the current block, first reference template samples (e.g., Toin FIG. 14) of a first reference block pointed with the first BV (e.g., vo in FIG. 14), and second reference template samples (e.g., T in FIG. 14) of a second reference block pointed with the second BV (e.g., vi in FIG. 14) may be obtained (e.g., at 705 of FIG. 14). For a weight (e.g., each weight associated with a respective weight index i = 0 ... nbweight, as shown at 706 of FIG. 14), the template samples of the reference blocks (e.g., Toin FIG. 14 and T in FIG. 14) may be averaged withthis weight, and the difference with the template samples (e.g., template samples T in FIG. 14) of the current block may be calculated (e.g., at 707 of FIG. 14). After testing the (e.g., all) allowed weights, a weight index (e.g., the best weight index associated with the minimum template cost, for example, Bi_IBC_weight_index) may be selected (e.g., at 708 of FIG. 14). The prediction samples (e.g., the prediction samples P in FIG. 14) for the current block may be generated, for example, by averaging these predictions with the selected weight (e.g., the first prediction signal Po, the second prediction signal Pi , and Bi_IBC_weight_index, as shown at 709 of FIG. 14). For example, the prediction samples P in FIG. 14 may be generated using Equation (3).

[0244] If the weight derivation is based on absolute value(s) of the BV(s), the best weight value may be obtained using two block vectors (e.g., directly derived by Equation (6) using the two block vectors at the decoder).

[0245] For an IBC block using bi-predictive IBC merge mode, the best weight value may be directly inferred from the one in the candidate list.

[0246] Decoding tools and techniques (e.g., as illustrated in FIG. 3) including, for example, one or more of entropy decoding, inverse quantization, inverse transformation, and differential decoding may be used to enable one or more examples as described herein in a decoder. For example, these decoding tools and techniques may be used to enable one or more of determining, for a video block, a first prediction signal associated with IBC bi-prediction and a second prediction signal associated with IBC bi-prediction applying a first weighting factor to the first prediction signal to generate a first weighted prediction signal; determining a second weighting factor based on the first weighting factor; applying the second weighting factor to the second prediction signal to generate a second weighted prediction signal; decoding the video block based on the first weighted prediction signal and the second weighted prediction signal; determining that IBC bi-prediction is enabled for the video block; obtaining a block vector associated with IBC bi-prediction; obtaining the weighting factor based on an absolute value of the block vector or based on a distance between a reference block of the video block and the video block; determining the prediction signal based on the obtained block vector; receiving an indication of a weighting factor; determining the weighting factor based on the received indication of the weighting factor; receiving an indication of a weighting factor index; determining the weighting factor based on the received indication of the weighting factor index; selecting the weighting factor from multiple weighting factors; obtaining a set of weighting factors and selecting the weighting factor from the set of weighting factors based on template matching; determining template samples of the video block; based on a block vector associated with IBC bi-prediction, determining reference template samples associated with a reference block of the video block; obtaining the weighting factor based onthe template samples of the video block and the reference template samples associated with the reference block of the video block.

[0247] Encoding tools and techniques (e.g., as illustrated in FIG. 2) including one or more of quantization, entropy coding, inverse quantization, inverse transformation, and differential coding may be used to enable one or more examples as described herein in the encoder. For example, these encoding tools and techniques may be used to enable one or more of: determining, for a video block, a first prediction signal associated with IBC bi-prediction and a second prediction signal associated with IBC bi-prediction applying a first weighting factor to the first prediction signal to generate a first weighted prediction signal; determining a second weighting factor based on the first weighting factor; applying the second weighting factor to the second prediction signal to generate a second weighted prediction signal; encoding the video block based on the first weighted prediction signal and the second weighted prediction signal; determining that IBC bi-prediction is enabled for the video block; obtaining a block vector associated with IBC bi-prediction; obtaining the weighting factor based on an absolute value of the block vector or based on a distance between a reference block of the video block and the video block; determining the prediction signal based on the obtained block vector; selecting the weighting factor from multiple weighting factors; obtaining a set of weighting factors and selecting the weighting factor from the set of weighting factors based on template matching; determining template samples of the video block; based on a block vector associated with IBC bi-prediction, determining reference template samples associated with a reference block of the video block; obtaining the weighting factor based on the template samples of the video block and the reference template samples associated with the reference block of the video block; selecting the weighting factor from the set of weighting factors based on rate distortion optimization (RDO); sending an indication of the weighting factor.

[0248] A method, process, apparatus, a TV, a set-top box, a cell phone, a tablet, medium storing instructions, medium storing data, a syntax element, a bitstream, or signal may be used for one or more of encoding, decoding, storing, displaying, transmitting, and / or receiving data according to one or more of the examples described herein. Although features and elements are described above in particular combinations, one of ordinary skill in the art will appreciate that each feature or element can be used alone or in any combination with the other features and elements. In addition, the methods described herein may be implemented in a computer program, software, or firmware incorporated in a computer- readable medium for execution by a computer or processor. Examples of computer-readable media include electronic signals (transmitted over wired or wireless connections) and computer-readable storage media. Examples of computer-readable storage media include, but are not limited to, a readonly 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

CLAIMS1 . A device for video decoding, comprising: a processor configured to: determine, based on a block vector (BV), a first prediction block of a video block in a current picture that comprises the video block; obtain a first weighting factor; apply the first weighting factor to the first prediction block to generate a first weighted prediction block; and decode the video block based on the first weighted prediction block.

2. A device for video encoding, comprising: a processor configured to: determine, based on a block vector (BV), a first prediction block of a video block in a current picture that comprises the video block; obtain a first weighting factor; apply the first weighting factor to the first prediction block to generate a first weighted prediction block; and encode the video block based on the first weighted prediction block.

3. The device of claim 1 , wherein the processor is further configured to: determine, for the video block, a second prediction block; determine a second weighting factor, the second weighting factor being different from the first weighting factor; and apply the second weighting factor to the second prediction block to generate a second weighted prediction block, wherein the video block is decoded further based on the second weighted prediction block.

4. The device of claim 1 , wherein the processor is further configured to: receive an indication of a weighting factor index; and determine the first weighting factor based on the received indication of the weighting factor index.

5. The device of claim 1, wherein the processor is further configured to: receive an indication of the first weighting factor; and determine the first weighting factor based on the received indication of the first weighting factor.

6. The device of claim 1 or claim 2, wherein the processor is further configured to: obtain a plurality of weighting factors; and select the first weighting factor from the plurality of weighting factors based on template matching, wherein the first weighting factor is associated with a minimum template cost compared to template costs associated with remaining weighting factors of the plurality of weighting factors.

7. The device of claim 1 or claim 2, wherein the processor is further configured to obtain the first weighting factor based on an absolute value of the block vector.

8. The device of claim 1 or claim 2, wherein the processor is further configured to: obtain a plurality of weighting factors; and select the weighting factor from the plurality of weighting factors based on rate distortion optimization (RDO), wherein the weighting factor is associated with a minimum RDO cost compared to RDO costs associated with remaining weighting factors of the plurality of weighting factors.

9. The device of claim 1 or claim 2, wherein the processor is further configured to: store block vector prediction (BVP) candidate information associated with a BVP candidate, wherein the BVP candidate information comprises a value of the first weighting factor, and wherein the first weighting factor is obtained based on the BVP candidate information.

10. The device of claim 1 or claim 2, wherein the BV is associated with intra-block copy (IBC) biprediction or a weighted intra template matching (IntraTMP) bi-prediction.11 . The device of claim 10, wherein the processor is further configured to: determine template samples of the video block; determine reference template samples associated with a reference block of the video block based on the BV; and obtain the first weighting factor based on the template samples of the video block and the reference template samples associated with the reference block of the video block.

12. A method for video decoding, comprising: determining, based on a block vector (BV), a first prediction block of a video block in a current picture that comprises the video block; obtaining a first weighting factor; applying the first weighting factor to the first prediction block to generate a first weighted prediction block; and decoding the video block based on the first weighted prediction block.

13. A method for video encoding, comprising: determining, based on a block vector (BV), a first prediction block of a video block in a current picture that comprises the video block; obtaining a first weighting factor; applying the first weighting factor to the first prediction block to generate a first weighted prediction block; and encoding the video block based on the first weighted prediction block.

14. The method of claim 12 or claim 13, comprising: determining, for the video block, a second prediction block; determining a second weighting factor, the second weighting factor being different from the first weighting factor; and applying the second weighting factor to the second prediction block to generate a second weighted prediction block.

15. The method of claim 12 or claim 13, comprising: obtaining a plurality of weighting factors; and selecting the first weighting factor from the plurality of weighting factors based on template matching, wherein the first weighting factor is associated with a minimum template cost compared to template costs associated with remaining weighting factors of the plurality of weighting factors.

Images