Cross component filter coefficients in bif

Abstract

Systems, methods, and instrumentalities may be configured for cross component filter coefficients in bilateral filtering (BIF). A device (e.g., a video decoding device) may be configured to obtain a collocated luma sample intensity value of a luma sample that is collocated with a chroma sample in a coding block. The device may obtain multiple neighboring chroma sample intensity values associated with multiple chroma samples that neighbor the chroma sample. The device may filter the chroma sample based on the collocated luma sample intensity value and the multiple neighboring chroma sample intensity values. The device may decode the video block based on the filtered chroma sample.

Description

IDVC_2023P00930WO PATENT CROSS COMPONENT FILTER COEFFICIENTS IN BIF CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] The application claims the benefit of European Application 23306684.4 filed October 2, 2023, the contents of which are incorporated by reference in their entirety herein. BACKGROUND

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

[0003] Systems, methods, and instrumentalities may be configured for cross component filter coefficients in bilateral filtering (BIF). A device (e.g., a video encoding and / or decoding device) may be configured to obtain a luma sample intensity value of a luma sample of a coding block, and the luma sample may be collocated with a chroma sample of the coding block. The device may obtain neighboring chroma sample intensity values associated with chroma samples, and the chroma samples may neighbor the chroma sample. The device may filter the chroma sample using a cross-component bilateral filter (BIF). The filtering of the chroma sample may be based on the luma sample intensity value, the neighboring chroma sample intensity values, and a chroma sample intensity value of the chroma sample. The device may decode the video block based on the filtered chroma sample.

[0004] The device may determine a weight based on one or more of the following: spatial distances between the chroma sample and the plurality of neighboring chroma samples, intensity differences between the chroma sample intensity value and the neighboring chroma sample intensity values, and intensity differences between the luma sample intensity value and luma intensity values of samples collocated with the neighboring chroma samples. The chroma sample may be filtered based further on the weight.

[0005] The device may determine one or more of a spatial parameter or a range parameter, and the weight may be determined based on the one or more spatial parameter or range parameter. The weightIDVC_2023P00930WO PATENT may be rounded to N-bit precision. The device may replace the chroma sample with a weighted average of the neighboring chroma sample intensity values, the chroma sample intensity value of the chroma sample, and the luma sample intensity value. The weights may be obtained from a look-up table (LUT). The BIF may be determined using a LUT. The LUT may include weights associated with a quantization parameter (QP). The device may determine, based on a rate-distortion optimization process, the luma sample based on candidate luma sample positions. The device may apply the cross-component BIF to a reconstructed coding tree unit (CTU).

[0006] Systems, methods, and instrumentalities may be configured for cross component filter coefficients in bilateral filtering (BIF). A device (e.g., a video decoding device) may be configured to obtain a collocated luma sample intensity value of a luma sample that is collocated with a chroma sample in a coding block. The device may obtain multiple neighboring chroma sample intensity values associated with multiple chroma samples that neighbor the chroma sample. The device may filter the chroma sample based on the collocated luma sample intensity value and the multiple neighboring chroma sample intensity values. The device may decode the video block based on the filtered chroma sample.

[0007] Filtering the chroma sample may include calculating a weighted average of the collocated luma sample intensity value and the multiple neighboring chroma sample intensity values. The device may replace a chroma sample intensity value of the chroma sample with the weighted average.

[0008] The weighted average may be calculated at least in part based on a distance and intensity differences between the chroma sample and the multiple neighboring samples of the chroma sample. The device may utilize a coefficient look-up-table (LUT) to derive a filter weight. The chroma sample may be filtered based on the derived filter weight.

[0009] Systems, methods, and instrumentalities may be configured for cross component filter coefficients in bilateral filtering (BIF). A device (e.g., a video encoding device) may be configured to obtain a collocated luma sample intensity value of a luma sample that is collocated with a chroma sample in a coding block. The device may obtain multiple neighboring chroma sample intensity values associated with multiple chroma samples that neighbor the chroma sample. The device may filter the chroma sample based on the collocated luma sample intensity value and the multiple neighboring chroma sample intensity values. The device may encode the video block based on the filtered chroma sample.

[0010] Filtering the chroma sample may include calculating a weighted average of the collocated luma sample intensity value and the multiple neighboring chroma sample intensity values. The device may replace a chroma sample intensity value of the chroma sample with the weighted average.

[0011] The weighted average may be calculated at least in part based on a distance and intensity differences between the chroma sample and the multiple neighboring samples of the chroma sample. TheIDVC_2023P00930WO PATENT device may utilize a coefficient look-up-table (LUT) to derive a filter weight. The chroma sample may be filtered based on the derived filter weight. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] FIG.1A is a system diagram illustrating an example communications system in which one or more disclosed embodiments may be implemented.

[0013] FIG.1B is a system diagram illustrating an example wireless transmit / receive unit (WTRU) that may be used within the communications system illustrated in FIG.1A according to an embodiment.

[0014] FIG.1C is a system diagram illustrating an example radio access network (RAN) and an example core network (CN) that may be used within the communications system illustrated in FIG.1A according to an embodiment.

[0015] FIG.1D is a system diagram illustrating a further example RAN and a further example CN that may be used within the communications system illustrated in FIG.1A according to an embodiment.

[0016] FIG.2 illustrates an example video encoder.

[0017] FIG.3 illustrates an example video decoder.

[0018] FIG.4 illustrates an example of a system in which various aspects and examples may be implemented.

[0019] FIG.5 illustrates an example of an 8x8 TU block and a filter aperture for a sample located at (1,1).

[0020] FIG.6 illustrates an example coefficient look-up-table that may be used to obtain weights of a filter.

[0021] FIG.7 illustrates example neighboring samples that may be utilized in a bilateral filter.

[0022] FIG.8 illustrates an example of windows covering two samples utilized in weight calculation.

[0023] FIG.9 illustrates examples of samples that may be used in the weighted sum.

[0024] FIG.10 illustrates an example filter (e.g., a bilateral filter (BIF)) (e.g., sample adaptive offset (SAO) may use samples from the deblocking stage as input).

[0025] FIG.11 illustrates an example naming convention for samples surrounding a center sample, ^^^^^^^^.

[0026] FIG.12 illustrates an example filtering stage of BIF-chroma.

[0027] FIG.13 illustrates an example of in-loop filtering .

[0028] FIG.14 illustrates an example of a decoding workflow (e.g., modified sample-adaptive offset (SOA) process) when cross-component SAO (CCSAO) may be applied.

[0029] FIG.15 illustrates an example of candidate positions that may be used for a CCSAO classifier.

[0030] FIG.16 illustrates an example joint clipping after SAO / BIF / CCSAO offsets may be added to the input sample.IDVC_2023P00930WO PATENT

[0031] FIG.17 depicts an example of four 1-D directional patterns for CCSAO edge orientation (EO) sample classification (e.g., horizontal (EO class = 0), vertical (EO class =1), 135° diagonal, and 45° diagonal)

[0032] FIG.18 illustrates an example bitstream structure.

[0033] FIG.19 illustrates an example flowchart of cross-component BIF.

[0034] FIG.20 illustrates an example of a luma BIF.

[0035] FIG.21 illustrates an example of a coefficient look-up-table that may be used to obtain the weights of the filter.

[0036] FIG.22 illustrates an example of samples that may be used in a weighted sum.

[0037] FIG.23 illustrates an example of a cross component chroma BIF.

[0038] FIG.24 illustrates an example of a coefficient look-up-table that may be used to obtain weights of a filter.

[0039] FIG.25 illustrates an example collocated luma sample. DETAILED DESCRIPTION

[0040] A more detailed understanding may be had from the following description, given by way of example in conjunction with the accompanying drawings.

[0041] 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.

[0042] As shown in FIG.1A, the communications system 100 may include wireless transmit / receive units (WTRUs) 102a, 102b, 102c, 102d, a RAN 104 / 113, a CN 106 / 115, a public switched telephone network (PSTN) 108, the Internet 110, and other networks 112, though it will be appreciated that the disclosed embodiments contemplate any number of WTRUs, base stations, networks, and / or network elements. Each of the WTRUs 102a, 102b, 102c, 102d may be any type of device configured to operate and / or communicate in a wireless environment. By way of example, the WTRUs 102a, 102b, 102c, 102d, any of which may be referred to as a “station” and / or a “STA,” may be configured to transmit and / or receiveIDVC_2023P00930WO PATENT wireless signals and may include a user equipment (UE), a mobile station, a fixed or mobile subscriber unit, a subscription-based unit, a pager, a cellular telephone, a personal digital assistant (PDA), a smartphone, a laptop, a netbook, a personal computer, a wireless sensor, a hotspot or Mi-Fi device, an Internet of Things (IoT) device, a watch or other wearable, a head-mounted display (HMD), a vehicle, a drone, a medical device and applications (e.g., remote surgery), an industrial device and applications (e.g., a robot and / or 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.

[0043] The communications systems 100 may also include a base station 114a and / or a base station 114b. Each of the base stations 114a, 114b may be any type of device configured to wirelessly interface with at least one of the WTRUs 102a, 102b, 102c, 102d to facilitate access to one or more communication networks, such as the CN 106 / 115, the Internet 110, and / or the other networks 112. By way of example, the base stations 114a, 114b may be a base transceiver station (BTS), a Node-B, an eNode B, a Home Node B, a Home eNode B, a gNB, a NR NodeB, a site controller, an access point (AP), a wireless router, and the like. While the base stations 114a, 114b are each depicted as a single element, it will be appreciated that the base stations 114a, 114b may include any number of interconnected base stations and / or network elements.

[0044] 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.

[0045] 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).IDVC_2023P00930WO PATENT

[0046] 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).

[0047] In an embodiment, the base station 114a and the WTRUs 102a, 102b, 102c may implement a radio technology such as Evolved UMTS Terrestrial Radio Access (E-UTRA), which may establish the air interface 116 using Long Term Evolution (LTE) and / or LTE-Advanced (LTE-A) and / or LTE-Advanced Pro (LTE-A Pro).

[0048] 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).

[0049] 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).

[0050] In other embodiments, the base station 114a and the WTRUs 102a, 102b, 102c may implement radio technologies such as IEEE 802.11 (i.e., Wireless Fidelity (WiFi), IEEE 802.16 (i.e., Worldwide Interoperability for Microwave Access (WiMAX)), CDMA2000, CDMA20001X, CDMA2000 EV-DO, Interim Standard 2000 (IS-2000), Interim Standard 95 (IS-95), Interim Standard 856 (IS-856), Global System for Mobile communications (GSM), Enhanced Data rates for GSM Evolution (EDGE), GSM EDGE (GERAN), and the like.

[0051] The base station 114b in FIG.1A may be a wireless router, Home Node B, Home eNode B, or access point, for example, and may utilize any suitable RAT for facilitating wireless connectivity in a localized area, such as a place of business, a home, a vehicle, a campus, an industrial facility, an air corridor (e.g., for use by drones), a roadway, and the like. In one embodiment, the base station 114b and the WTRUs 102c, 102d may implement a radio technology such as IEEE 802.11 to establish a wireless local area network (WLAN). In an embodiment, the base station 114b and the WTRUs 102c, 102d may implement a radio technology such as IEEE 802.15 to establish a wireless personal area network (WPAN).IDVC_2023P00930WO PATENT In yet another embodiment, the base station 114b and the WTRUs 102c, 102d may utilize a cellular-based RAT (e.g., WCDMA, CDMA2000, GSM, LTE, LTE-A, LTE-A Pro, NR etc.) to establish a picocell or femtocell. As shown in FIG.1A, the base station 114b may have a direct connection to the Internet 110. Thus, the base station 114b may not be required to access the Internet 110 via the CN 106 / 115.

[0052] The RAN 104 / 113 may be in communication with the CN 106 / 115, which may be any type of network configured to provide voice, data, applications, and / or voice over internet protocol (VoIP) services to one or more of the WTRUs 102a, 102b, 102c, 102d. The data may have varying quality of service (QoS) requirements, such as differing throughput requirements, latency requirements, error tolerance requirements, reliability requirements, data throughput requirements, mobility requirements, and the like. The CN 106 / 115 may provide call control, billing services, mobile location-based services, pre-paid calling, Internet connectivity, video distribution, etc., and / or perform high-level security functions, such as user authentication. Although not shown in FIG.1A, it will be appreciated that the RAN 104 / 113 and / or the CN 106 / 115 may be in direct or indirect communication with other RANs that employ the same RAT as the RAN 104 / 113 or a different RAT. For example, in addition to being connected to the RAN 104 / 113, which may be utilizing a NR radio technology, the CN 106 / 115 may also be in communication with another RAN (not shown) employing a GSM, UMTS, CDMA 2000, WiMAX, E-UTRA, or WiFi radio technology.

[0053] 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.

[0054] 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.

[0055] FIG.1B is a system diagram illustrating an example WTRU 102. As shown in FIG.1B, the WTRU 102 may include a processor 118, a transceiver 120, a transmit / receive element 122, a speaker / microphone 124, a keypad 126, a display / touchpad 128, non-removable memory 130, removableIDVC_2023P00930WO PATENT memory 132, a power source 134, a global positioning system (GPS) chipset 136, and / or other peripherals 138, among others. It will be appreciated that the WTRU 102 may include any sub-combination of the foregoing elements while remaining consistent with an embodiment.

[0056] 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.1B depicts the processor 118 and the transceiver 120 as separate components, it will be appreciated that the processor 118 and the transceiver 120 may be integrated together in an electronic package or chip.

[0057] 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.

[0058] Although the transmit / receive element 122 is depicted in FIG.1B as a single element, the WTRU 102 may include any number of transmit / receive elements 122. More specifically, the WTRU 102 may employ MIMO technology. Thus, in one embodiment, the WTRU 102 may include two or more transmit / receive elements 122 (e.g., multiple antennas) for transmitting and receiving wireless signals over the air interface 116.

[0059] 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.

[0060] 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 outputIDVC_2023P00930WO PATENT 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).

[0061] 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.

[0062] 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.

[0063] 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.

[0064] 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 anIDVC_2023P00930WO PATENT 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)).

[0065] FIG.1C is a system diagram illustrating the RAN 104 and the CN 106 according to an embodiment. As noted above, the RAN 104 may employ an E-UTRA radio technology to communicate with the WTRUs 102a, 102b, 102c over the air interface 116. The RAN 104 may also be in communication with the CN 106.

[0066] 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.

[0067] Each of the eNode-Bs 160a, 160b, 160c may be associated with a particular cell (not shown) and may be configured to handle radio resource management decisions, handover decisions, scheduling of users in the UL and / or DL, and the like. As shown in FIG.1C, the eNode-Bs 160a, 160b, 160c may communicate with one another over an X2 interface.

[0068] The CN 106 shown in FIG.1C may include a mobility management entity (MME) 162, a serving gateway (SGW) 164, and a packet data network (PDN) gateway (or PGW) 166. While each of the foregoing elements are depicted as part of the CN 106, it will be appreciated that any of these elements may be owned and / or operated by an entity other than the CN operator.

[0069] The MME 162 may be connected to each of the eNode-Bs 162a, 162b, 162c in the RAN 104 via an S1 interface and may serve as a control node. For example, the MME 162 may be responsible for authenticating users of the WTRUs 102a, 102b, 102c, bearer activation / deactivation, selecting a particular serving gateway during an initial attach of the WTRUs 102a, 102b, 102c, and the like. The MME 162 may provide a control plane function for switching between the RAN 104 and other RANs (not shown) that employ other radio technologies, such as GSM and / or WCDMA.

[0070] 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.IDVC_2023P00930WO PATENT

[0071] 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.

[0072] The CN 106 may facilitate communications with other networks. For example, the CN 106 may provide the WTRUs 102a, 102b, 102c with access to circuit-switched networks, such as the PSTN 108, to facilitate communications between the WTRUs 102a, 102b, 102c and traditional land-line communications devices. For example, the CN 106 may include, or may communicate with, an IP gateway (e.g., an IP multimedia subsystem (IMS) server) that serves as an interface between the CN 106 and the PSTN 108. In addition, the CN 106 may provide the WTRUs 102a, 102b, 102c with access to the other networks 112, which may include other wired and / or wireless networks that are owned and / or operated by other service providers.

[0073] Although the WTRU is described in FIGS.1A-1D as a wireless terminal, it is contemplated that in certain representative embodiments that such a terminal may use (e.g., temporarily or permanently) wired communication interfaces with the communication network.

[0074] In representative embodiments, the other network 112 may be a WLAN.

[0075] A WLAN in Infrastructure Basic Service Set (BSS) mode may have an Access Point (AP) for the BSS and one or more stations (STAs) associated with the AP. The AP may have an access or an interface to a Distribution System (DS) or another type of wired / wireless network that carries traffic in to and / or out of the BSS. Traffic to STAs that originates from outside the BSS may arrive through the AP and may be delivered to the STAs. Traffic originating from STAs to destinations outside the BSS may be sent to the AP to be delivered to respective destinations. Traffic between STAs within the BSS may be sent through the AP, for example, where the source STA may send traffic to the AP and the AP may deliver the traffic to the destination STA. The traffic between STAs within a BSS may be considered and / or referred to as peer-to- peer traffic. The peer-to-peer traffic may be sent between (e.g., directly between) the source and destination STAs with a direct link setup (DLS). In certain representative embodiments, the DLS may use an 802.11e DLS or an 802.11z tunneled DLS (TDLS). A WLAN using an Independent BSS (IBSS) mode may not have an AP, and the STAs (e.g., all of the STAs) within or using the IBSS may communicate directly with each other. The IBSS mode of communication may sometimes be referred to herein as an “ad- hoc” mode of communication.

[0076] When using the 802.11ac infrastructure mode of operation or a similar mode of operations, the AP may transmit a beacon on a fixed channel, such as a primary channel. The primary channel may be a fixed width (e.g., 20 MHz wide bandwidth) or a dynamically set width via signaling. The primary channel may be the operating channel of the BSS and may be used by the STAs to establish a connection with the AP. In certain representative embodiments, Carrier Sense Multiple Access with Collision AvoidanceIDVC_2023P00930WO PATENT (CSMA / CA) may be implemented, for example 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.

[0077] 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.

[0078] 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).

[0079] Sub 1 GHz modes of operation are supported by 802.11af and 802.11ah. The channel operating bandwidths, and carriers, are reduced in 802.11af and 802.11ah relative to those used in 802.11n, and 802.11ac.802.11af supports 5 MHz, 10 MHz and 20 MHz bandwidths in the TV White Space (TVWS) spectrum, and 802.11ah supports 1 MHz, 2 MHz, 4 MHz, 8 MHz, and 16 MHz bandwidths using non- TVWS spectrum. According to a representative embodiment, 802.11ah may support Meter Type Control / Machine-Type Communications, such as MTC devices in a macro coverage area. MTC devices may have certain capabilities, for example, limited capabilities including support for (e.g., only support for) certain and / or limited bandwidths. The MTC devices may include a battery with a battery life above a threshold (e.g., to maintain a very long battery life).

[0080] WLAN systems, which may support multiple channels, and channel bandwidths, such as 802.11n, 802.11ac, 802.11af, and 802.11ah, include a channel which may be designated as the primary channel. The primary channel may have a bandwidth equal to the largest common operating bandwidth supported by all STAs in the BSS. The bandwidth of the primary channel may be set and / or limited by a STA, from among all STAs operating in a BSS, which supports the smallest bandwidth operating mode. In the example of 802.11ah, the primary channel may be 1 MHz wide for STAs (e.g., MTC type devices) that support (e.g., only support) a 1 MHz mode, even if the AP, and other STAs in the BSS support 2 MHz, 4 MHz, 8 MHz, 16 MHz, and / or other channel bandwidth operating modes. Carrier sensing and / or NetworkIDVC_2023P00930WO PATENT 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.

[0081] In the United States, the available frequency bands, which may be used by 802.11ah, are from 902 MHz to 928 MHz. In Korea, the available frequency bands are from 917.5 MHz to 923.5 MHz. In Japan, the available frequency bands are from 916.5 MHz to 927.5 MHz. The total bandwidth available for 802.11ah is 6 MHz to 26 MHz depending on the country code.

[0082] FIG.1D is a system diagram illustrating the RAN 113 and the CN 115 according to an embodiment. As noted above, the RAN 113 may employ an NR radio technology to communicate with the WTRUs 102a, 102b, 102c over the air interface 116. The RAN 113 may also be in communication with the CN 115.

[0083] 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).

[0084] 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).

[0085] 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 otherIDVC_2023P00930WO PATENT RANs (e.g., such as eNode-Bs 160a, 160b, 160c). In the standalone configuration, WTRUs 102a, 102b, 102c may utilize one or more 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.

[0086] Each of the gNBs 180a, 180b, 180c may be associated with a particular cell (not shown) and may be configured to handle radio resource management decisions, handover decisions, scheduling of users in the UL and / or DL, support of network slicing, dual connectivity, interworking between NR and E- UTRA, routing of user plane data towards User Plane Function (UPF) 184a, 184b, routing of control plane information towards Access and Mobility Management Function (AMF) 182a, 182b and the like. As shown in FIG.1D, the gNBs 180a, 180b, 180c may communicate with one another over an Xn interface.

[0087] The CN 115 shown in FIG.1D may include at least one AMF 182a, 182b, at least one UPF 184a,184b, at least one Session Management Function (SMF) 183a, 183b, and possibly a Data Network (DN) 185a, 185b. While each of the foregoing elements are depicted as part of the CN 115, it will be appreciated that any of these elements may be owned and / or operated by an entity other than the CN operator.

[0088] 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.IDVC_2023P00930WO PATENT

[0089] The SMF 183a, 183b may be connected to an AMF 182a, 182b in the CN 115 via an N11 interface. The SMF 183a, 183b may also be connected to a UPF 184a, 184b in the CN 115 via an N4 interface. The SMF 183a, 183b may select and control the UPF 184a, 184b and configure the routing of traffic through the UPF 184a, 184b. The SMF 183a, 183b may perform other functions, such as managing and allocating UE IP address, managing PDU sessions, controlling policy enforcement and QoS, providing downlink data notifications, and the like. A PDU session type may be IP-based, non-IP based, Ethernet- based, and the like.

[0090] 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.

[0091] 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.

[0092] In view of Figures 1A-1D, and the corresponding description of Figures 1A-1D, one or more, or all, of the functions described herein with regard to one or more of: WTRU 102a-d, Base Station 114a-b, eNode-B 160a-c, MME 162, SGW 164, PGW 166, gNB 180a-c, AMF 182a-b, UPF 184a-b, SMF 183a-b, DN 185a-b, and / or any other device(s) described herein, may be performed by one or more emulation devices (not shown). The emulation devices may be one or more devices configured to emulate one or more, or all, of the functions described herein. For example, the emulation devices may be used to test other devices and / or to simulate network and / or WTRU functions.

[0093] 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 communicationIDVC_2023P00930WO PATENT network. The emulation device may be directly coupled to another device for purposes of testing and / or performing testing using over-the-air wireless communications.

[0094] 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.

[0095] 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.

[0096] The aspects described and contemplated in this application may be implemented in many different forms. FIGs.5-25 described herein may provide some examples, but other examples are contemplated. The discussion of FIGs.5-25 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.

[0097] 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.

[0098] Various methods are described herein, and each of the methods comprises one or more steps or actions for achieving the described method. Unless a specific order of steps or actions is required for proper operation of the method, the order and / or use of specific steps and / or actions may be modified or combined. Additionally, terms such as “first,” “second,” etc., may be used in various examples to modify an element, component, step, operation, etc., such as, for example, a “first decoding” and a “second decoding.” Use of such terms does not imply an ordering to the modified operations unless specifically required. So, in this example, the first decoding need not be performed before the second decoding, and may occur, for example, before, during, or in an overlapping time period with the second decoding.IDVC_2023P00930WO PATENT

[0099] Various methods and other aspects described in this application may be used to modify modules, for example, decoding modules, of a video encoder 200 and decoder 300 as shown in FIG.2 and FIG.3. Moreover, the subject matter disclosed herein may be applied, for example, to any type, format or version of video coding, whether described in a standard or a recommendation, whether pre-existing or future- developed, and extensions of any such standards and recommendations. Unless indicated otherwise, or technically precluded, the aspects described in this application may be used individually or in combination.

[0100] Various numeric values are used in examples described the present application, such as 1, 2, 4, 7, 8, 16, 32, 64, etc. These and other specific values are for purposes of describing examples and the aspects described are not limited to these specific values.

[0101] FIG.2 is a diagram showing an example video encoder 200. Variations of example encoder 200 are contemplated, but the encoder 200 is described below for purposes of clarity without describing all expected variations.

[0102] 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 (e.g., which may include film grain parameters determined by pre-processing as described herein) may be associated with the pre-processing and attached to the bitstream.

[0103] 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.

[0104] 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 non- transformed residual signal. The encoder can bypass both transform and quantization, i.e., the residual is coded directly without the application of the transform or quantization processes.

[0105] The encoder decodes an encoded block to provide a reference for further predictions. The quantized transform coefficients are de-quantized (240) and inverse transformed (250) to decode prediction residuals. Combining (255) the decoded prediction residuals and the predicted block, an image block is reconstructed. In-loop filters (265) are applied to the reconstructed picture to perform, for example,IDVC_2023P00930WO PATENT deblocking / SAO (Sample Adaptive Offset) filtering to reduce encoding artifacts. The filtered image is stored at a reference picture buffer (280).

[0106] 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.

[0107] 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).

[0108] 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.

[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, in at least one example, the processing and encoder / decoder elements of system 400 are distributed across multiple ICs and / or discrete components. In various examples, the system 400 is communicatively coupled to one or more other systems, or other electronic devices, via, for example, a communications bus or through dedicated input and / or output ports.IDVC_2023P00930WO PATENT 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 during encoding or decoding. In other examples, however, a memory external to the processing device (for example, the processing device may be either the processor 410 or the encoder / decoder module 430) is used for one or more of these functions. The external memory may be the memory 420 and / or the storage device 440, for example, a dynamic volatile memory and / or a non-volatile flash memory. In several examples, an externalIDVC_2023P00930WO PATENT 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 band-limiting a signal to a band of frequencies), (ii) down-converting 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 down-converted 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, down-converting 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, down-converting, 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 understood that various aspects of input processing, for example, Reed-Solomon error correction, may be implemented, for example, within a separate input processing IC or within processor 410 as necessary. Similarly, aspects of USB or HDMI interface processing may be implemented within separate interface ICs or within processor 410 as necessary. The demodulated, error corrected, and demultiplexed stream is provided to variousIDVC_2023P00930WO PATENT processing elements, including, for example, processor 410, and encoder / decoder 430 operating in combination with the memory and storage elements to process the data stream 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 Inter- 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 another device. The display 475 can also be integrated with other components (for example, as in a smart phone), or separate (for example, an external monitor for a laptop). The other peripheral devices 495 include, in various examples, one or more of a stand-alone digital video disc (or digital versatile disc) (DVD, for both terms), a disk player, a stereo system, and / or a lighting system. Various examples use one or more peripheral devices 495 that provide a function based on the output of the system 400. For example, a disk player performs the function of playing the output of the system 400.IDVC_2023P00930WO PATENT

[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, inverse quantization, inverse transformation, and differential decoding. In various examples, such processes also, or alternatively, include processes performed by a decoder of various implementations described in this application, for example, obtaining a luma sample intensity value of a luma sample of a coding block, wherein the luma sample is collocated with a chroma sample of the coding block; obtaining a plurality of neighboring chroma sample intensity values associated with a plurality of chroma samples, wherein the plurality of chroma samples neighbor the chroma sample; filtering the chroma sample using a cross- component bilateral filter (BIF), wherein the filtering of the chroma sample is based on the luma sampleIDVC_2023P00930WO PATENT intensity value, the plurality of neighboring chroma sample intensity values, and a chroma sample intensity value of the chroma sample; and encoding the video block based on the filtered chroma sample.

[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, obtaining a luma sample intensity value of a luma sample of a coding block, wherein the luma sample is collocated with a chroma sample of the coding block; obtaining a plurality of neighboring chroma sample intensity values associated with a plurality of chroma samples, wherein the plurality of chroma samples neighbor the chroma sample; filtering the chroma sample using a cross-component bilateral filter (BIF), wherein the filtering of the chroma sample is based on the luma sample intensity value, the plurality of neighboring chroma sample intensity values, and a chroma sample intensity value of the chroma sample; and encoding the video block based on the filtered chroma sample.

[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, coding syntax on intensity interval, grain parameters, block offset, scaling factor, 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.IDVC_2023P00930WO PATENT

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

[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 theIDVC_2023P00930WO PATENT selection of the first listed option (A) only, or the selection of the second listed option (B) only, or the selection of both options (A and B). As a further example, in the cases of “A, B, and / or C” and “at least one of A, B, and C,” such phrasing is intended to encompass the selection of the first listed option (A) only, or the selection of the second listed option (B) only, or the selection of the third listed option (C) only, or the selection of the first and the second listed options (A and B) only, or the selection of the first and third listed options (A and C) only, or the selection of the second and third listed options (B and C) only, or the selection of all three options (A and B and C). This may be extended, as is clear to one of ordinary skill in this and related arts, for as many items as are listed.

[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, number of intensity intervals, number of model values, grain parameters, grain identification, scaling factor, 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 claimIDVC_2023P00930WO PATENT categories and types. For example, features described herein may be implemented in a bitstream or signal that includes information generated as described herein. The information may allow a decoder to decode a bitstream, the encoder, bitstream, and / or decoder according to any of the embodiments described. For example, features described herein may be implemented by creating and / or transmitting and / or receiving and / or decoding a bitstream or signal. For example, features described herein may be implemented a method, process, apparatus, medium storing instructions, medium storing data, or signal. For example, features described herein may be implemented by a TV, set-top box, cell phone, tablet, or other electronic device that performs decoding. The TV, set-top box, cell phone, tablet, or other electronic device may display (e.g., using a monitor, screen, or other type of display) a resulting image (e.g., an image from residual reconstruction of the video bitstream). The TV, set-top box, cell phone, tablet, or other electronic device may receive a signal including an encoded image and perform decoding.

[0139] Features described herein may be associated with bilateral filtering (BIF) in context of video coding. Performing quantization in the transform domain may be a technique for preserving information in images and video compared to quantizing in the pixel domain. Quantized transform blocks may produce ringing artifacts around edges, both in still images and in moving objects in videos. Applying a bilateral filter (BIF) may (e.g., significantly) reduce ringing artifacts. BIF may be applied on decoded sample values directly after the inverse transform. BIF may be performed on reconstructed samples post deblock filtering, with a larger filter, and with an calculated (e.g., optimized) LUT (approximation of the weights of the filter)

[0140] A bilateral filter may be derived from gaussian filters and may be described as follows: a (e.g., each) sample in the reconstructed picture may be replaced by a weighted average of itself and its neighbors. The weights may be calculated based on the distance from the center sample as well as the difference in sample values. Because the filter is in the shape of a small plus sign as shown in FIG.5, the distances (e.g., all of the distances) may be 0 or 1.

[0141] FIG.5 illustrates an example of an 8x8 TU block and the filter aperture for the sample located at (1,1). A sample located at (i, j) may be filtered using its neighboring sample (k, l). The weight ^^^^, ^^^^) is the weight assigned for sample (k, l) to filter the sample (i, j), and it may be defined as:

[0142] I(i, j ) and I(k, l) may be the original reconstructed intensity value of samples (i, j)respectively. ^^^^^^^^is the spatial parameter, and ^^^^^^^^is the range parameter. The property (or strength) of the bilateral filter may be controlled by these two parameters. Samples located closer to the sample to be filtered, and samples having smaller intensity difference to the sample to be filtered, may have largerIDVC_2023P00930WO PATENT weight than samples further away and with larger intensity difference. ^^^^^^^^is based on the transform unit size (Eq.2), and ^^^^^^^^is based on the QP used for the current block (Eq.3). σ= 0.92 –min(TU block width, TU block height)d( ^^^^ ^^^^.2)

[0143] The bilateral filter may applied to a (e.g., each) TU block directly after the inverse transform in both the encoder and the decoder. Subsequent intra-coded blocks may predict from the sample values that have been filtered with the bilateral filter. The bilateral filter operation may be included in the rate-distortion decisions in the encoder and this may be how the filter has been implemented (e.g., in JEM).

[0144] A sample in the transform unit may be filtered using its direct neighboring samples (e.g., neighboring samples only). The filter may have a plus sign shaped filter aperture centered at the sample to be filtered.

[0145] The output filtered sample value ^^^^^^^^( ^^^^, ^^^^) may be calculated as:

[0146] For TU sizes larger than 16 × 16, the block may be treated as (e.g., several) 16 × 16 blocks using TU block width = TU block height = 16 in Equation 2. Rectangular blocks may be treated as (e.g., several) instances of square blocks. In order to reduce the number of calculations, the proposed bilateral filter may be implemented using a look-up-table (LUT) storing (e.g., all) weights for a particular QP in a two- dimensional array. The LUT may use the intensity difference between the sample to be filtered and the reference sample as the index of the LUT in one dimension, and the TU size as the index in another dimension. For (e.g., efficient) storage of the LUT, weights may be rounded to 8-bit precision.

[0147] FIG.6 illustrates a coefficient look-up-table that may be used to obtain the weights of the filter. the proposed bilateral filter may be a five-tap filter in the shape of a plus sign. The strength of the filter may be based (e.g., based only) on the TU size and QP.

[0148] The filter strength may be lower for blocks using inter prediction. Inter predicted blocks may have less residual than intra predicted blocks. The reconstruction of inter predicted blocks may be filtered less. The filter strength for intra predicted blocks may be set as described herein, and for inter predicted blocks the following spatial weight may be used: σmin(TU block width, T )d= 0.72 –U block height(^^^^ ^^^^.5)IDVC_2023P00930WO PATENT

[0149] The size of the lookup table (LUT) for the bilateral filter may be is reduced. The goal of the LUT may be to pre-calculate the weights of the bilateral filter:so that the filtered pixel ^^^^^^^^( ^^^^, ^^^^) can be calculated as (^^^^ ^^^^.7)for the center weight, e.g., the weight for the center pixel, ^^^^ = ^^^^ and ^^^^ = ^^^^. Hence ( ^^^^ − ^^^^) = ( ^^^^ − ^^^^) = 0 and ^^^^( ^^^^, ^^^^) = ^^^^( ^^^^, ^^^^) and the center weight ^^^^( ^^^^, ^^^^, ^^^^, ^^^^) may be 1.0.

[0150] For (e.g., all) other weights, ( ^^^^ − ^^^^)2+ ( ^^^^ − ^^^^)2= 1 since the 4-neighbors (e.g., since only the 4-neighbors) of a pixel are included in the filtering (a “plus-shaped” filter kernel). Thereforewhere ^^^^^^^^is the intensity of the center pixel. Since the center weight is 1.0, a LUT may or may not be used (e.g., needed) for it.

[0151] For the other weights, a 3D LUT may be indexed over the following dimensions. Modes: the variable ^^^^^^^^may take 6 different values depending upon the TU size and type of block; 3 for intra blocks (e.g., 3 each for intra blocks) (4×4, 8×8, and 16×16 blocks) and 3 for inter blocks (e.g., 3 each for inter blocks) (4×4, 8×8, and 16×16 blocks). (Rectangular blocks may use the smaller dimension.). QPs: the variable σris calculated from the QP value and the filter may be (e.g., may only be) turned on for QP 18 and higher: For QP 17 and lower σrmay become too small to change the filtered value. Therefore, this dimension may take 34 different values (18 through 51). Absolute intensity difference: The value ‖I − Ic‖ may take 1024 different values for 10-bit luma values.

[0152] A weight may be stored using an unsigned short. A brute force implementation may need 6*34*1024*2 = 417792 bytes of LUT memory.

[0153] The division may be removed and replaced with a multiplication and a lookup-table (LUT). To keep the size of the LUT as small as possible, from Eq.7 the nominator and the denominator of the division may be as small as possible. To reduce the nominator, the filtering equation may be rewritten using differences. To reduce the denominator, the large center weight value for inter blocks of size 16×16 and larger may be avoided by turning the filter off for these blocks. Since the filter (shape 2x2) touches (e.g., since the filter may only touch) the center pixel and its 4-neighbors, this equation (Eq.7) may be written asIDVC_2023P00930WO PATENT where ^^^^^^^^is the intensity of the center pixel, and ^^^^^^^^, ^^^^^^^^, ^^^^^^^^and ^^^^^^^^are the intensities for the left, right, above and below pixel respectively. ^^^^^^^^is the weight for the center pixel, and ^^^^^^^^, ^^^^^^^^, ^^^^^^^^and ^^^^^^^^are the corresponding weights for the neighboring pixels.

[0154] The nominator may become relatively big. Equation 8 may be rewritten aswhere Δ ^^^^^^^^= ^^^^^^^^− ^^^^^^^^and Δ ^^^^^^^^= ^^^^^^^^− ^^^^^^^^, etc.

[0155] When an (e.g., large) difference in intensity Δ ^^^^ occurs, the bilateral filter may choose an (e.g., small) weight ^^^^. The product Δ ^^^^ ∗ ^^^^ may be small, since Δ ^^^^ may be small or ^^^^ may be small.

[0156] The denominator in Equation 9 may be equal to ^^^^^^^^+ ^^^^^^^^+ ^^^^^^^^+ ^^^^^^^^+ ^^^^^^^^. The maximum value for the non-center weights ^^^^^^^^, ^^^^^^^^, ^^^^^^^^and ^^^^^^^^may be 31. The center weight may take the following values, as shown in Table 1. Table 1: Center weight values based on the prediction mode and the TB length (e.g., JEM). min(TUwidth, TUheight) 4 8 16 intra 65 81 196 inter 113 196 4079

[0157] A simplification may be proposed for the bilateral filter. For a (e.g., each) block, the inverse quantized transform coefficients may be examined, and if they include one (e.g., only one) non-zero coefficient (e.g., include only one non-zero coefficient) that is at the DC position, bilateral filtering may be skipped for the associated reconstructed block.

[0158] A filtering process may be described herein. Once a bilateral filter is applied to luma blocks with non-zero transform coefficients and slice quantization parameter larger than 17, the usage of the bilateral filter may or may not be signaled (e.g., may not need to be signaled). The bilateral filter, if applied, may be performed on decoded samples right after the inverse transform. The filter parameters, e.g., weights, may be explicitly derived from the coded information. The filtering process (Eq.7) may be rewritten as:IDVC_2023P00930WO PATENT where ^^^^0, 0is the intensity of the current sample and ^^^^0′,0is the modified intensity of the current sample, ^^^^^^^^, 0and ^^^^^^^^(∙) are the intensity and weighting parameter for the k-th neighboring sample, respectively.

[0159] An example of a (e.g., one) current sample and its four neighboring samples (e.g., K=4), in the shape of a plus sign, is depicted in FIG.7. FIG.7 illustrates neighboring samples utilized in a bilateral filter. 5

[0160] The weight ^^^^^^^^( ^^^^) associated with the k-th neighboring sample may be defined as follows: ^^^^^^^^( ^^^^) = ^^^^ ^^^^ ^^^^ ^^^^ ^^^^ ^^^^ ^^^^ ^^^^^^^^× ^^^^ ^^^^ ^^^^ ^^^^ ^^^^^^^^( ^^^^) wherein10 and ^^^^^^^^is dependent on the coded mode and coding block sizes.

[0161] To modify (e.g., further improve) the coding performance, for inter-coded blocks, the intensity difference between current sample and one of its neighboring samples may be replaced by a representative intensity difference among two windows covering current sample and the neighboring sample. The equation of filtering process may be revised to: 15wherein ^^^^^^^^, ^^^^and ^^^^0, ^^^^represent the m-th sample value within the windows centered at ^^^^^^^^, 0and ^^^^0, 0, respectively.

[0162] The window size may be set to 3×3. FIG.8 illustrates windows covering two samples utilized in weight calculation. Two windows covering ^^^^2, 0and ^^^^0, 0are depicted in FIG.8. A spatial filter strength 20 adjustment based on CU area size for a bilateral filter may be described herein.

[0163] The size of the LUT may be reduced to approximate the numerator and denominator in the following equation: ^^^^^^^^ ^^^^Δ ^^^^ ^^^^ + ^^^^ ^^^^Δ ^^^^ ^^^^ + ^^^^ ^^^^Δ ^^^ ^^^^^ + ^^^^ ^^^^Δ ^^^^ ^^^^^^^^ = ^^^^ ^^^^ +^^^^ + ^^^^ + ^^^^ + ^^^^ + ^^^ ,^^^^ ^^^^ ^^^^ ^^^^ ^ ^^^^where ^^^^^^^^is the filtered sample, ^^^^^^^^is the intensity of the center sample (the sample to be filtered), ^^^^^^^^, ^^^^^^^^, ^^^^^^^^25 and ^^^^^^^^are the intensity of the samples to the left, to the right, above and below respectively.

[0164] FIG.9 illustrates samples that may be used in the weighted sum. The delta values are differences against the center sample; Δ ^^^^^^^^= ^^^^^^^^− ^^^^^^^^and Δ ^^^^^^^^= ^^^^^^^^− ^^^^^^^^, etc. The weights are calculated asIDVC_2023P00930WO PATENTwhere ^^^^ can be ^^^^, ^^^^, ^^^^ or ^^^^.

[0165] The bilateral filter may be combined with the sample adaptive offset (SAO) loop filter. The filter may be carried out in the sample adaptive offset (SAO) loop-filter stage, as shown in IG.10 illustrates examples wherein the proposed filter (BIF) and SAO use samples from the deblocking stage as input. Both create an offset, and these may be added to the input sample and clipped. Both the proposed bilateral filter (BIF) and SAO may use samples from deblocking as input. A filter may create (e.g., each filter may create) an offset per sample, and these may be added to the input sample and then clipped.

[0166] FIG.10 illustrates examples wherein the proposed filter (BIF) and SAO use samples from the deblocking stage as input. Both create an offset, and these may be added to the input sample and clipped. The output sample ^^^^^^^^ ^^^^ ^^^^may be obtained as ^^^^ ^^^^ ^^^^ ^^^^ = ^^^^ ^^^^ ^^^^ ^^^^3(^^^^ ^^^^ + Δ ^^^^ ^^^^ ^^^^ ^^^^ + Δ ^^^^ ^^^^ ^^^^ ^^^^)where ^^^^^^^^is the input sample from deblocking, Δ ^^^^^^^^ ^^^^ ^^^^is the offset from the bilateral filter and ΔI^^^^ ^^^^ ^^^^is the offset from SAO.

[0167] A diamond 5x5 filter kernel may be used together with 26 tables of 16 entries (e.g., may be used together with 26 tables of 16 entries each). The filter kernel may operate in the same loop-filter stage as SAO, as depicted in FIG.11. FIG.11 illustrates a naming convention for samples surrounding the center sample, ^^^^^^^^.

[0168] ^^^^^^^^the center and the samples surrounding the center sample are denoted A, B, L and R that stands for above, below, left and right and where NW, NE, SW, SE stands for north-west etc. AA stands for above-above, BB for below-below etc.

[0169] The BIF-chroma may be performed in parallel with the SAO process as shown in FIG.12. The BIF-chroma and SAO may use the same chroma samples that are produced by the deblocking filter as input and generate two offsets per chroma sample in parallel. The two offsets may (e.g., may both) be added to the input chroma sample to obtain a sum, which may be clipped to form the final output chroma sample value. The proposed BIF-chroma may provide an on / off control mechanism on the CTU level and slice level. FIG.12 illustrates an example filtering stage of BIF-chroma.

[0170] The in-loop filtering flow and BIF’s position in the in-loop filtering flow may be presented in FIG. 13. FIG.13 illustrates an example of in-loop filtering. For an output sample, three offsets may be calculated and clipped:IDVC_2023P00930WO PATENT

[0171] Cross-component Sample-adaptive offset (CCSAO) may be used to refine reconstructed chroma samples. The CCSAO may classify the reconstructed samples into different categories, may derive one offset for a (e.g., each) category, and may add the offset to the reconstructed samples in that category. While SAO may use (e.g., only use) one single luma / chroma component of current sample as input, the CCSAO may utilize all three components to classify the current sample into different categories. To facilitate the parallel processing, the output samples from the de-blocking filter may be used as the input of the CCSAO.

[0172] FIG.14 shows an example of the decoding workflow (e.g., modified SOA process) when the CCSAO may be applied.

[0173] In CCSAO, BO may be used to enhance the quality of the reconstructed samples. For a given luma / chroma sample, three candidate samples (e.g., one collocated Y sample, one collocated U sample, and one collocated V sample) may be selected to classify the given sample into different categories. The sample values of these three selected samples may be classified into three different bands { ^^^^ ^^^^ ^^^^ ^^^^^^^^, ^^^^ ^^^^ ^^^^ ^^^^^^^^, ^^^^ ^^^^ ^^^^ ^^^^^^^^}, and a joint index ^^^^ may represent the category of the given sample. One offset may be signaled and added to the reconstructed samples that fall into that category, which can be formulated as: ^^^^ ^^^^ ^^^^ ^^^^^^^^= ( ^^^^^^^^ ^^^^ ^^^^∙ ^^^^^^^^) ≫ ^^^^ ^^^^ ^^^^ ^^^^ ^^^^ ^^^^ ^^^^ =(^^^^ ^^^^ ^^^^ ^^^^ ∙ ^^^^ ^^^^)≫ ^^^^ ^^^^^^^^ ^^^^ ^^^^ ^^^^^^^^= ( ^^^^^^^^ ^^^^ ^^^^∙ ^^^^^^^^) ≫ ^^^^ ^^^^ ^^^^ = ^^^^ ^^^^ ^^^^ ^^^^^^^^∙ ( ^^^^^^^^∙ ^^^^^^^^) + ^^^^ ^^^^ ^^^^ ^^^^^^^^∙ ^^^^^^^^+ ^^^^ ^^^^ ^^^^ ^^^^^^^^^^^^′ ^^^^ ^^^^ ^^^^ = ^^^^ ^^^^ ^^^^ ^^^^1( ^^^^ ^^^^ ^^^^ ^^^^ + ^^^^ ^^^^ ^^^^ ^^^^ ^^^^ ^^^^[ ^^^^])

[0174] Where { ^^^^^^^^ ^^^^ ^^^^, ^^^^^^^^ ^^^^ ^^^^, ^^^^^^^^ ^^^^ ^^^^} may be the three selected collocated samples used to classify current sample, { ^^^^^^^^, ^^^^^^^^, ^^^^^^^^} may be the numbers of equally divided bands applied to { ^^^^^^^^ ^^^^ ^^^^, ^^^^^^^^ ^^^^ ^^^^, ^^^^^^^^ ^^^^ ^^^^} full range respectively; ^^^^ ^^^^ may be the internal coding bit-depth; ^^^^′^^^^ ^^^^ ^^^^and ^^^^^^^^ ^^^^ ^^^^may be the reconstructed samples before and after the CCSAO is applied; and ^^^^^^^^ ^^^^ ^^^^ ^^^^ ^^^^[^^^^]may be the value of the CCSAO offset applied to i-th BO category. The collocated luma sample may be chosen from 9 candidate positions, while the collocated chroma sample positions may be fixed, as depicted in FIG.15. FIG.15 depicts an example illustration of the candidate positions that may be used for the CCSAO classifier.

[0175] Different classifiers may be applied to different local regions (e.g., to further enhance the whole picture quality). The parameters for a (e.g., each) classifier (e.g., the position of ^^^^^^^^ ^^^^ ^^^^, ^^^^^^^^, ^^^^^^^^, ^^^^^^^^, and offsets) may be signaled at the picture level, and the classifier to be used may be explicitly signaled and switched at the CTB level. For a (e.g., each) classifier, the maximum of { ^^^^^^^^, ^^^^^^^^, ^^^^^^^^} may be set to {16, 4, 4}, and offsets may be constrained to be within the range [-15, 15]. In examples, at most 4 classifiers may be used per frame.IDVC_2023P00930WO PATENT

[0176] FIG.16 depicts an example joint clipping after SAO / BIF / CCSAO offsets may be added the input sample. SAO, Bilateral filter (BIF) and CCSAO offset may be computed in parallel, added to the reconstructed chroma samples, and jointly clipped, as depicted in FIG.16.

[0177] FIG.17 depicts four 1-D directional patterns for CCSAO EO sample classification (e.g., horizontal (EO class = 0), vertical (EO class =1), 135° diagonal, and 45° diagonal). The edge-based classifier of CCSAO may use the four 1-D directional patterns for sample classification: horizontal, vertical, 135° diagonal and 45° diagonal, as depicted in FIG.17.

[0178] For every 1-D pattern, a (e.g, each) sample may be classified based on the sample difference between the luma sample value labeled as “c” and its two neighbor luma samples labeled as “a” and “b” along the selected 1-D pattern.

[0179] The encoder may decide the best 1-D directional pattern using the rate-distortion optimization (RDO) and signal this additional information in a (e.g., each) classifier / set. Both the sample differences “a- c” and “b-c” may be compared against a pre-defined threshold value (Th) to derive the final “class_idx” information.

[0180] The encoder may select the best “Th” value from an array of pre-defined threshold values (e.g., based on RDO) and the index into the “Th” array may be signaled.

[0181] In examples, a distinction between the CCSAO edge-based classifier and the SAO edge classifier may be that, in the former, Chroma samples may use the co-located Luma samples for deriving the edge information (e.g., samples “a”, “c” and “b” are the co-located luma samples) whereas, in the later Chroma samples may use its own neighboring samples for deriving the edge information.

[0182] The Edge-based classifier process may be formulated as follows: Ea=(a-c<0)? (a-c<(-Th)? 0:1) : (a-c<(Th)? 2:3) (2) Eb=(b-c<0)? (b-c<(-Th)? 0:1) : (b-c<(Th)? 2:3) (3) class_idx = iB * 16 + Ea * 4 + Eb (4) C'rec=Clip1(Crec+σCCSAO [class_idx]) (5)

[0183] The variable “iB” in equation (3) may be derived as follows. iB= (cur ∙Ncur)≫BD (or) iB= (col1 ∙Ncol1)≫BD (or) iB= (col2 ∙Ncol2)≫BD (6) where sample “cur” may be the current sample being processed and col1 and col2 may be the co-located samples. When Luma samples may be processed, col1 and col2 may be the co-located Cb and Cr samples respectively. When Chroma (Cb) samples may be processed, col1 and col2 may be the co-located Y and Crsamples respectively. When Chroma (Cr) samples may be processed, col1 and col2 may be the co-located Y and Cb samples respectively.IDVC_2023P00930WO PATENT

[0184] Based on RDO, the encoder may signal one of the samples (e.g., “cur”, “col1", "col2") that may have been used in deriving the band information.

[0185] Feature(s) associated with adaptation parameter set (APS) are provided herein. Video coding standards may implement APSs to signal any information (e.g., ALF parameters, Luma mapping, Chroma scaling, etc.) that may be required for the encoding / decoding for future slices / pictures until the next random-access point.

[0186] The information may relate to Luma Mapping with Chroma Scaling (LMCS) parameters. They may relate to loop filters such as Adaptive Loop Filter (ALF) and Cross-Component Adaptive Loop Filter (CCALF). In the latter case, APSs may carry parameters such as filter coefficients and clipping indices.

[0187] APSs may be signaled in a separate Network Abstraction Layer Unit (NALU). An NALU may be a syntax structure comprising an indication of the type of data to follow and bytes including that data in the form of a raw byte sequence payload. The goal of using APS may be to be able to send data that may not need to be updated at frame / slice level and can be reused.

[0188] ALF and CCALF signaled filter sets may be carried in dedicated APS NALUs, called ALF APSs. An ALF APS may include Luma ALF filters, Chroma ALF filters and CCALF filters. In examples, up to eight ALF APSs can be used by the encoder / decoder at the same time.

[0189] Referenced ALF APSs indices may be coded at slice level (e.g., in slice headers). Referenced ALF APSs indices may be coded with relevant slice-level flags that may be related to ALF filtering decisions at slice level. A CTU (e.g., each CTU) may signal the index of the ALF APS that it uses.

[0190] FIG.18 illustrates an example bitstream structure (e.g., for ALF parameters). ALF parameters alf_aps_param, in APS may describe ALF Luma filters, ALF Chroma filters, and CCALF filters. alf_sh_param in slice header or picture header may include the referenced ALF APSs indices and / or slice / picture level ALF and CCALF flags. alf_ctu_param at CTU level may include, if applicable, the ALF APS index and / or further ALF and CCALF filter control syntax elements.

[0191] The BIF filtering of the chroma components (e.g., Cr, Cb) may be made without using information from luma. A luma component may be used in chroma BIF filtering to modify the performance. Features described herein may be associated with in-loop filtering and with modifying reconstructed samples. In SAO, the 3 components Y, Cr, Cb (or YUV) may be processed separately. CCSAO may modify SAO by using cross- component approach. SAO may use one single luma / chroma component of a current sample as input. The CCSAO may utilize multiple components (e.g., all three components) to classify the current sample into different categories as described herein. The cross-component approach may generate gains in in-loop filtering. The cross-component approach may be applied on BIF (e.g., in association with one or more features described herein).IDVC_2023P00930WO PATENT

[0192] CCSAO may modify SAO by using a cross-component approach. Bilateral Filtering (BIF) may be modified for chroma by using a cross-component approach. FIG.19 illustrates an example flowchart of a cross-component BIF. The BIF chroma filter coefficients may be modulated by using luma information as depicted in FIG.19.

[0193] The cross-component bilateral filter may be described as follows: a luma sample (e.g., each luma sample) in the reconstructed picture may be replaced by a weighted average of itself and its neighbors; a chroma sample (e.g., each chroma sample) in the reconstructed picture may be replaced by a weighted average of itself and its neighbors and its collocated luma sample.

[0194] The weights may be calculated based on the distance from the center sample as well as the difference in sample values. The cross component filter coefficients in BIF may be described herein. A cross 2x2 filter kernel as shown in FIG.5 may be described herein, and (e.g., all of) the distances may be 0 (center) or 1. A larger kernel shape 5x5 is shown in FIG.5.

[0195] A luma component may be described herein. A luma sample in the reconstructed picture may be replaced by a weighted average of itself and its neighbors, as illustrated in FIG.20. FIG.20 illustrates an example of a luma BIF. A luma sample located at (i, j), will be filtered using its neighboring sample (k, l). The weight ^^^^, ^^^^) is the weight assigned for sample (k, l) to filter the sample (i, j), and it is defined as:I (i, j ) and I (k, l) may be the original reconstructed intensity value of luma samples (i, j) and (k,l) respectively.

[0196] ^^^^^^^^is the spatial parameter, and ^^^^^^^^is the range parameter. The property (or strength) of the bilateral filter may be controlled by these two parameters. Samples located closer to the sample to be filtered, and samples having smaller intensity difference to the sample to be filtered, may have larger weight than samples further away and with larger intensity difference. ^^^^^^^^may be described herein. min height)

[0197] The proposed bilateral filter may be applied to a (e.g., each) reconstructed samples on a (e.g., each) TU block directly after the inverse transform at both the encoder and the decoder.

[0198] In examples, a cross-component BIF may be applied to a reconstructed CTU after the deblock filtering (DBF) at both the encoder and the decoder. In examples, a sample (e.g., each sample) in the transform unit may be filtered using its direct neighboring samples (e.g., using only its direct neighboring samples). The filter may have a plus sign shaped filter aperture centered at the sample to be filtered. The output filtered sample valueis calculated as:IDVC_2023P00930WO PATENT

[0199] In order to reduce the number of calculations, the bilateral filter may be implemented using a look-up-table (LUT) storing (e.g., all) weights for a QP in a two-dimensional array. The LUT may use the intensity difference between the sample to be filtered and the reference sample as the index of the LUT in one dimension, and the TU size as the index in the other dimension. FIG.21 illustrates an example coefficient look-up-table that may be used to obtain the weights of the filter. For storage efficiency of the LUT, the weights may be rounded to 8-bit precision, as illustrated in FIG.21.

[0200] The bilateral filter may be a five-tap filter in the shape of a plus sign. The strength of the filter may be based on the TU size and QP. As described herein, it may be a (e.g., larger) filter shape, such as a diamond 5x5.

[0201] The luma filtered sample may be rewritten: ^^^^^^^^ ^^^^Δ ^^^^ ^^^^ + ^^^^ ^^^^Δ ^^^^ ^^^^ + ^^^^ ^^^^Δ ^^^ ^^^^^ + ^^^^ ^^^^Δ ^^^^ ^^^^^^^^ = ^^^^ ^^^^ +^^^^ ,^^^^ + ^^^^ ^^^^ + ^^^^ ^^^^ + ^^^^ ^^^^ + ^^^^ ^^^^where ^^^^^^^^is the filtered sample, ^^^^^^^^is the intensity of the center sample (the sample to be filtered), ^^^^^^^^, ^^^^^^^^, ^^^^^^^^and ^^^^^^^^are the intensity of the samples to the left, to the right, above and below respectively.

[0202] FIG.22 illustrates example samples that may be used in the weighted sum.The delta values may be differences against the center sample; Δ ^^^^^^^^= ^^^^^^^^− ^^^^^^^^and Δ ^^^^^^^^= ^^^^^^^^− ^^^^^^^^, etc. The weights may be calculated aswhere ^^^^ may be ^^^^, ^^^^, ^^^^ or ^^^^.

[0203] A chroma component may be described herein. A chroma sample (e.g., each chroma sample) in the reconstructed picture may be replaced by a weighted average of itself and its neighbors and its collocated luma sample, as shown in FIG.23. FIG.23 illustrates an example cross component chroma BIF.

[0204] A component sample located at (i, j) may be filtered using its neighboring sample (k, l) and the collocated luma sample (e.g., may be referred to as a cross-component BIF or CCBIF). The weightis the weight assigned for sample (k, l) to filter the sample (i, j), and it is defined as:

[0205] I (i, j ) and I(k, l) are the original reconstructed intensity value of the collocated luma samples (i, j) and (k,l) respectively. C(i, j ) and C(k, l) are the original reconstructed intensity value of chroma samples (i, j) and (k,l) respectively. C is Cr or Cb.IDVC_2023P00930WO PATENT

[0206] ^^^^^^^^is the spatial parameter, and ^^^^^^^^is the range parameter. The properties (or strength) of the bilateral filter may be controlled by these two parameters. Samples located closer to the sample to be filtered, and samples having smaller intensity difference to the sample to be filtered, may have larger weight than samples further away and with larger intensity difference. ^^^^^^^^may be kept as described herein (e.g., a different ^^^^^^^^may be associated with a different result. σmin(TU block width, TU block height)d= 0.92 –40

[0207] In examples, the same σrmay be used in ω(i, j, k, l) computation for luma and chroma. In examples, (e.g., different) range parameter σ may be used for‖‖C(^^^^, ^^^^)– C(^^^^, ^^^^)‖22^^^^2. ^^^^ is a scale factor that weights the ∆ ^^^^^^^^^^^^_ ^^^^ℎ ^^^^ ^^^^ ^^^^ ^^^^. ^^^^ is a scale factor that weights the ∆ ^^^^^^^^. In examples, ^^^^ = 1 and ^^^^ = 0.2. In examples, ^^^^ = 1 − ^^^^ with ^^^^ = 0.8. In examples, ‖C(^^^^, ^^^^)– C(^^^^, ^^^^)‖2 ‖^^^^(^^^^, ^^^^)– ^^^^(^^^^,2− ^^^^ � may be clipped to keep th^^^^)‖2 ^^^^^2^^^e same limit value for -2 ^^^^^^^^The LUT may not need to be retrained. If clipping does not occur, the LUT may be recalculated for the range (e.g., the new range). In examples, a new LUT may be pre-computed and available at encoder and decoder sides.

[0208] The proposed bilateral filter may be applied to a reconstructed sample (e.g., each reconstructed sample) on a TU block (e.g., each TU block) directly after the inverse transform at both the encoder and the decoder. In examples, a cross component BIF may be applied to a reconstructed CTU after the deblock filtering (DBF) at both the encoder and the decoder. In examples, a chroma sample in the transform unit may be filtered using its direct neighboring samples and the collocated luma sample. The filter may have a plus sign shaped filter aperture centered at the sample to be filtered. The output filtered sample value ^^^^^^^^( ^^^^, ^^^^) may be calculated as:

[0209] In order to reduce the number of calculations, the proposed bilateral filter may be implemented using a look-up-table (LUT) storing (e.g., all) weights for a QP in a two-dimensional array. The LUT may use the intensity difference between the sample to be filtered and the reference sample as the index of the LUT in one dimension, and the TU size as the index in the other dimension. For storage of the LUT, theIDVC_2023P00930WO PATENT weights may be rounded to 8-bit precision, as shown in FIG.24. FIG.24 illustrates an example coefficient look-up-table that may be used to obtain the weights of the filter.

[0210] The bilateral filter may be a five-tap filter in the shape of a plus sign. The strength of the filter may be based on the TU size and QP. As described herein, it may be a larger filter shape, such as a diamond 5x5.

[0211] The bilateral filter operation may be included in the rate-distortion decisions in the encoder to enable / disable the computation of cross-component BIF for chroma. A flag may be signaled in the slice or CTU header for chroma components.

[0212] In examples, the best collocated luma sample may be found by using a rate distortion optimizer (RDO). As detailed in CCSAO, the collocated luma sample may be chosen from 9 candidate positions, and the collocated chroma sample positions may be fixed, as depicted in FIG.25. FIG.25 illustrates a collocated luma sample.

[0213] Although features and elements are described above in particular combinations, one of ordinary skill in the art will appreciate that each feature or element can be used alone or in any combination with the other features and elements. In addition, the methods described herein may be implemented in a computer program, software, or firmware incorporated in a computer-readable medium for execution by a computer or processor. Examples of computer-readable media include electronic signals (transmitted over wired or wireless connections) and computer-readable storage media. Examples of computer-readable storage media include, but are not limited to, a read only memory (ROM), a random access memory (RAM), a register, cache memory, semiconductor memory devices, magnetic media such as internal hard disks and removable disks, magneto-optical media, and optical media such as CD-ROM disks, and digital versatile disks (DVDs). A processor in association with software may be used to implement a radio frequency transceiver for use in a WTRU, UE, terminal, base station, RNC, or any host computer.

Claims

IDVC_2023P00930WO PATENT Claims 1. A video decoding device, comprising: a processor configured to: obtain a luma sample intensity value of a luma sample of a coding block, wherein the luma sample is collocated with a chroma sample of the coding block; obtain a plurality of neighboring chroma sample intensity values associated with a plurality of chroma samples, wherein the plurality of chroma samples neighbor the chroma sample; filter the chroma sample using a cross-component bilateral filter (BIF), wherein the filtering of the chroma sample is based on the luma sample intensity value, the plurality of neighboring chroma sample intensity values, and a chroma sample intensity value of the chroma sample; and decode the video block based on the filtered chroma sample.

2. The device of claim 1, wherein the processor is further configured to: determine a weight based on one or more of the following: a plurality of spatial distances between the chroma sample and the plurality of neighboring chroma samples, a plurality of intensity differences between the chroma sample intensity value and the neighboring chroma sample intensity values, and a plurality of intensity differences between the luma sample intensity value and a plurality of luma intensity values of a plurality of samples collocated with the neighboring chroma samples, wherein the chroma sample is filtered based further on the weight.

3. The device of claim 2, wherein the processor is further configured to: determine one or more of a spatial parameter or a range parameter, wherein the weight is determined based on the one or more spatial parameter or range parameter.

4. The device of any of claims 2-3, wherein the weight is rounded to N-bit precision.

5. The device of claim 1, wherein the processor is further configured to: replace the chroma sample with a weighted average of the plurality of neighboring chroma sample intensity values, the chroma sample intensity value of the chroma sample, and the luma sample intensity value, wherein weights are obtained from a look-up table (LUT).

6. The device of any of claims 1-5, wherein the BIF is determined using a LUT.IDVC_2023P00930WO PATENT 7. The device of any of claims 1-6, wherein the LUT comprises weights associated with a quantization parameter (QP).

8. The device of any of claims 1-7, wherein the processor is further configured to determine, based on a rate-distortion optimization process, the luma sample based on a plurality of candidate luma sample positions.

9. The device of any of claims 1-8, wherein the processor is further configured to apply the cross- component BIF to a reconstructed coding tree unit (CTU).

10. A device for video encoding, comprising: a processor configured to: obtain a luma sample intensity value of a luma sample of a coding block, wherein the luma sample is collocated with a chroma sample of the coding block; obtain a plurality of neighboring chroma sample intensity values associated with a plurality of chroma samples, wherein the plurality of chroma samples neighbor the chroma sample; filter the chroma sample using a cross-component bilateral filter (BIF), wherein the filtering of the chroma sample is based on the luma sample intensity value, the plurality of neighboring chroma sample intensity values, and a chroma sample intensity value of the chroma sample; and encode the video block based on the filtered chroma sample.

11. The device of claim 10, wherein the processor is further configured to: determine a weight based on one or more of the following: a plurality of spatial distances between the chroma sample and the plurality of neighboring chroma samples, a plurality of intensity differences between the chroma sample intensity value and the neighboring chroma sample intensity values, and a plurality of intensity differences between the luma sample intensity value and a plurality of luma intensity values of a plurality of samples collocated with the neighboring chroma samples, wherein the chroma sample is filtered based further on the weight.

12. The device of claim 11, wherein the processor is further configured to:IDVC_2023P00930WO PATENT determine one or more of a spatial parameter or a range parameter, wherein the weight is determined based on the one or more spatial parameter or range parameter.

13. The device of any of claims 11-12, wherein the weight is rounded to N-bit precision.

14. The device of claim 10, wherein the processor is further configured to: replace the chroma sample with a weighted average of the plurality of neighboring chroma sample intensity values, the chroma sample intensity value of the chroma sample, and the luma sample intensity value, wherein weights are obtained from a look-up table (LUT).

15. The device of any of claims 10-14, wherein the BIF is determined using a LUT.

16. The device of any of claims 10-15, wherein the LUT comprises weights associated with a quantization parameter (QP).

17. The device of any of claims 10-16, wherein the processor is further configured to determine, based on a rate-distortion optimization process, the luma sample based on a plurality of candidate luma sample positions.

18. The device of any of claims 10-17, wherein the processor is further configured to apply the cross- component BIF to a reconstructed coding tree unit (CTU).

19. The device of any of claims 1 to 18, further comprising a memory operatively connected to the processor.

20. A method for video decoding, comprising: obtaining a luma sample intensity value of a luma sample of a coding block, wherein the luma sample is collocated with a chroma sample of the coding block; obtaining a plurality of neighboring chroma sample intensity values associated with a plurality of chroma samples, wherein the plurality of chroma samples neighbor the chroma sample; filtering the chroma sample using a cross-component bilateral filter (BIF), wherein the filtering of the chroma sample is based on the luma sample intensity value, the plurality of neighboring chroma sample intensity values, and a chroma sample intensity value of the chroma sample; and decoding the video block based on the filtered chroma sample.IDVC_2023P00930WO PATENT 21. The method of claim 20, wherein the method further comprises: determining a weight based on one or more of the following: a plurality of spatial distances between the chroma sample and the plurality of neighboring chroma samples, a plurality of intensity differences between the chroma sample intensity value and the neighboring chroma sample intensity values, and a plurality of intensity differences between the luma sample intensity value and a plurality of luma intensity values of a plurality of samples collocated with the neighboring chroma samples, wherein the chroma sample is filtered based further on the weight.

22. The method of claim 21, wherein the method further comprises: determining one or more of a spatial parameter or a range parameter, wherein the weight is determined based on the one or more spatial parameter or range parameter.

23. The method of any of claims 21-22, wherein the weight is rounded to N-bit precision.

24. The method of claim 20, wherein the method further comprises: replacing the chroma sample with a weighted average of the plurality of neighboring chroma sample intensity values, the chroma sample intensity value of the chroma sample, and the luma sample intensity value, wherein weights are obtained from a look-up table (LUT).

25. The method of any of claims 20-24, wherein the BIF is determined using a LUT.

26. The method of any of claims 20-25, wherein the LUT comprises weights associated with a quantization parameter (QP).

27. The method of any of claims 20-26, wherein the method further comprises determining, based on a rate-distortion optimization process, the luma sample based on a plurality of candidate luma sample positions.

28. The method of any of claims 20-27, wherein the method further comprises applying the cross- component BIF to a reconstructed coding tree unit (CTU).IDVC_2023P00930WO PATENT 29. A method for video encoding, comprising: obtaining a luma sample intensity value of a luma sample of a coding block, wherein the luma sample is collocated with a chroma sample of the coding block; obtaining a plurality of neighboring chroma sample intensity values associated with a plurality of chroma samples, wherein the plurality of chroma samples neighbor the chroma sample; filtering the chroma sample using a cross-component bilateral filter (BIF), wherein the filtering of the chroma sample is based on the luma sample intensity value, the plurality of neighboring chroma sample intensity values, and a chroma sample intensity value of the chroma sample; and encoding the video block based on the filtered chroma sample.

30. The method of claim 29, wherein the method further comprises: determining a weight based on one or more of the following: a plurality of spatial distances between the chroma sample and the plurality of neighboring chroma samples, a plurality of intensity differences between the chroma sample intensity value and the neighboring chroma sample intensity values, and a plurality of intensity differences between the luma sample intensity value and a plurality of luma intensity values of a plurality of samples collocated with the neighboring chroma samples, wherein the chroma sample is filtered based further on the weight.

31. The method of claim 30, wherein the method further comprises: determining one or more of a spatial parameter or a range parameter, wherein the weight is determined based on the one or more spatial parameter or range parameter.

32. The method of any of claims 30-31, wherein the weight is rounded to N-bit precision.

33. The method of claim 29, wherein the method further comprises: replacing the chroma sample with a weighted average of the plurality of neighboring chroma sample intensity values, the chroma sample intensity value of the chroma sample, and the luma sample intensity value, wherein weights are obtained from a look-up table (LUT).

34. The method of any of claims 29-33, wherein the BIF is determined using a LUT.IDVC_2023P00930WO PATENT 35. The method of any of claims 29-34, wherein the LUT comprises weights associated with a quantization parameter (QP).

36. The method of any of claims 29-35, wherein the method further comprises determining, based on a rate-distortion optimization process, the luma sample based on a plurality of candidate luma sample positions.

37. The method of any of claims 29-36, wherein the method further comprises applying the cross- component BIF to a reconstructed coding tree unit (CTU).

38. A computer-readable medium comprising medium comprising instructions for causing one or more processors to perform the method of any one of claims 20-37.

39. A computer program product which is stored on a non-transitory computer readable medium and comprises program code instructions for implementing the steps of a method according to at least one of claims 20-37 when executed by a processor.

40. Video data comprising information representative of the video block encoded according to one of the methods of any of claims 30-37.

Images