Luma residual usage in chroma ALF and CCALF

Abstract

Systems, methods, and instrumentalities can be provided for encoding and / or decoding intra pictures when a chroma CTB belongs to a slice coded in separate tree mode or nodes. A video coding device can determine that a current chroma coding tree block (CTB) is associated with a slice coded in separate tree mode. The video coding device can calculate a full residual luma block collocated with the current chroma CTB. The video coding device can apply the full residual luma block collocated with the current chroma CTB as input to a chroma adaptive loop filter (ALF) or a cross-component adaptive loop filter (CCALF).

Description

[0001] Cross-reference to related applications This application claims the benefit of European Provisional Application No. 23306672.9, filed on 2 October 2023, the contents of which are hereby incorporated herein by reference. Background Technology

[0002] Video codec systems can be used to compress digital video signals, for example, to reduce the storage and / or transmission bandwidth required for such signals. Video codec systems can include, for example, block-based, wavelet-based, and / or object-based systems. Summary of the Invention

[0003] When the chroma CTB belongs to a slice encoded or decoded in a single-tree mode or node, systems, methods, and instruments for encoding and / or decoding intra-frame images can be provided. Video codecs can determine the association between the current chroma codec tree block (CTB) and a slice encoded or decoded in a single-tree mode. The video codec can calculate the complete residual luma block co-located with the current chroma CTB. The video codec can then apply the complete residual luma block co-located with the current chroma CTB as input to a chroma adaptive loop filter (ALF) or a cross-component adaptive loop filter (CCALF).

[0004] Based on the determination of the association between the current chroma CTB and the slice encoded and decoded in a separate tree mode, the video codec can derive the co-located luma block. The video codec can obtain intra-frame reference samples associated with the co-located luma block. The video codec can obtain intra-frame prediction modes associated with the co-located luma block. The video codec can predict the co-located luma block based on the intra-frame reference samples and the intra-frame prediction modes. The video codec can compute the residual co-located luma block. The complete residual luma block can be computed as the difference between the reconstructed luma block and the predicted co-located luma block. The video codec can compute the complete residual luma block co-located with the current chroma CTB. The complete residual luma block can be computed using at least the residual co-located luma block. The video codec can apply the complete residual luma block co-located with the current chroma CTB as input to a chroma adaptive loop filter (ALF) or a cross-component adaptive loop filter (CCALF).

[0005] A complete residual luminance block can be computed using each of the complete residual luminance blocks associated with each of the multiple chroma blocks of the current chroma CTB. The video codec can store the residual co-located luminance block within the complete residual luminance block co-located with the current chroma CTB. The video codec can apply the residual chroma block co-located with the current chroma CTB as input to the chroma ALF and CCALF. If cross-component prediction is used for the current chroma CTB, the intra-prediction mode associated with the co-located luminance block can be derived using at least one of a template-based intra-prediction mechanism or a decoder-side intra-prediction mechanism. The intra-prediction mode of the complete residual luminance block can be derived as the most representative intra-prediction mode among multiple intra-prediction modes stored in memory. Attached Figure Description

[0006] Figure 1A This is a system diagram illustrating an example communication system in which one or more of the disclosed embodiments may be implemented.

[0007] Figure 1B To illustrate, according to an embodiment, it is possible to Figure 1A The diagram shows a system diagram of an example wireless transmit / receive unit (WTRU) used in a communication system.

[0008] Figure 1C To illustrate, according to an embodiment, it is possible to Figure 1A The diagram illustrates a system diagram of an example radio access network (RAN) and an example core network (CN) used within a communication system.

[0009] Figure 1D To illustrate, according to an embodiment, it is possible to Figure 1A The diagram shows another example RAN and another example CN used in the communication system.

[0010] Figure 2 The illustration shows a sample video encoder.

[0011] Figure 3 The illustration shows an example video decoder.

[0012] Figure 4 The illustration shows an example of a system that can implement various aspects and examples.

[0013] Figure 5 An example of a loop filter is illustrated.

[0014] Figure 6A An example of a luminance ALF 7x7 diamond filter is illustrated.

[0015] Figure 6B An example of a chroma ALF 5x5 diamond filter is illustrated.

[0016] Figure 7 The illustration shows an example of the shape of the signaled filter for luminance ALF signaling transmission.

[0017] Figure 8 The illustration shows an example of a CCALF-filtered chroma sample and its relative position in the luminance plane when the chroma location type is 0 and the chroma format is 4:2:0.

[0018] Figure 9 The illustration shows an example of the CCALF filter shape for a chroma location type of 0 and a chroma format of 4:2:0.

[0019] Figure 10 An example of the filter shape for chroma ALF is shown.

[0020] Figure 11 An example of the filter shape in CCALF is shown.

[0021] Figure 12 An example of a codec tree unit and codec tree concept is illustrated to represent a compressed image.

[0022] Figure 13 The illustration shows an example of dividing the codec tree unit into codec units, prediction units, and transform units.

[0023] Figure 14 The illustration shows an example of partitioning the codec unit into prediction units.

[0024] Figure 15 The illustration shows an example of a quadtree plus binary tree (QTBT) CTU representation.

[0025] Figure 16 The illustration shows examples of horizontal and vertical ternary tree codec unit segmentation patterns.

[0026] Figure 17 The illustration shows an example of a set of codec unit segmentation modes supported in video encoding and decoding.

[0027] Figure 18 The illustration shows an example of video encoding and decoding using the luminance residual signals from chroma ALF and CCALF. Detailed Implementation

[0028] A more detailed understanding can be obtained from the following description, which is given in illustrative form in conjunction with the accompanying drawings.

[0029] Figure 1AThe diagram illustrates an example communication system 100 in which one or more of the disclosed embodiments may be implemented. The communication system 100 may be a multiple access system that provides content such as voice, data, video, messaging, broadcasting, etc., to multiple wireless users. The communication system 100 enables multiple wireless users to access such content by sharing system resources, including wireless bandwidth. For example, the communication system 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 Spectrum OFDM (ZT UW DTS-s OFDM), Unique Word OFDM (UW-OFDM), Resource Block Filtered OFDM, Filter Bank Multicarrier (FBMC), etc.

[0030] like Figure 1A As shown, the communication system 100 may include wireless transmit / receive units (WTRUs) 102a, 102b, 102c, 102d, RAN 104 / 113, CN 106 / 115, public switched telephone network (PSTN) 108, Internet 110, and other networks 112. However, 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. For example, any of the WTRUs 102a, 102b, 102c, and 102d, which may be referred to as a “station” and / or “STA”, may be configured to transmit and / or receive wireless signals and may include user equipment (UE), mobile stations, fixed or mobile subscriber units, subscription-based units, pagers, cellular phones, personal digital assistants (PDAs), smartphones, laptops, netbooks, personal computers, wireless sensors, hotspots or Mi-Fi devices, Internet of Things (IoT) devices, watches or other wearable devices, head-mounted displays (HMDs), vehicles, drones, medical devices and applications (e.g., remote surgery), industrial devices and applications (e.g., robots and / or other wireless devices operating in industrial and / or automated processing chain scenarios), consumer electronics devices, devices operating on commercial and / or industrial wireless networks, etc. Any of the WTRUs 102a, 102b, 102c, and 102d may be interchangeably referred to as a UE.

[0031] The communication system 100 may also include base station 114a and / or base station 114b. Each of base stations 114a and 114b may be any type of device configured to wirelessly interface with at least one of WTRUs 102a, 102b, 102c, and 102d to facilitate access to one or more communication networks such as CN 106 / 115, the Internet 110, and / or other networks 112. For example, base stations 114a and 114b may be a basic transceiver station (BTS), Node-B, eNodeB, home Node B, home eNode B, gNB, NR NodeB, site controller, access point (AP), wireless router, etc. Although each of base stations 114a and 114b is depicted as a single element, it will be appreciated that base stations 114a and 114b may include any number of interconnected base stations and / or network elements.

[0032] Base station 114a may be part of RAN 104 / 113, which may also include other base stations and / or network elements (not shown), such as base station controllers (BSCs), radio network controllers (RNCs), relay nodes, etc. Base station 114a and / or base station 114b may be configured to transmit and / or receive radio signals on one or more carrier frequencies, which may be referred to as cells (not shown). These frequencies may be in licensed spectrum, unlicensed spectrum, or a combination of licensed and unlicensed spectrum. A cell may provide coverage of a specific geographic area, which may be relatively fixed or may change over time. A cell may be further divided into cell sectors. For example, the cell associated with base station 114a may be divided into three sectors. Therefore, in one embodiment, base station 114a may include three transceivers, i.e., one transceiver for each sector of the cell. In embodiments, 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 a desired spatial direction.

[0033] Base stations 114a and 114b can communicate with one or more of WTRUs 102a, 102b, 102c, and 102d via air interface 116. The air interface can be any suitable wireless communication link (e.g., radio frequency (RF), microwave, centimeter wave, micrometer wave, infrared (IR), ultraviolet (UV), visible light, etc.). Air interface 116 can be established using any suitable radio access technology (RAT).

[0034] More specifically, as noted above, communication system 100 can be a multiple access system and can employ one or more channel access schemes, such as CDMA, TDMA, FDMA, OFDMA, SC-FDMA, etc. For example, base station 114a in RAN 104 / 113 and WTRUs 102a, 102b, 102c can implement radio technologies such as Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access (UTRA), which can use Wideband CDMA (WCDMA) to establish air interfaces 115 / 116 / 117. WCDMA can include communication protocols such as High-Speed ​​Packet Access (HSPA) and / or Evolved HSPA (HSPA+). HSPA can include High-Speed ​​Downlink (DL) Packet Access (HSDPA) and / or High-Speed ​​UL Packet Access (HSUPA).

[0035] In the embodiment, base station 114a and WTRUs 102a, 102b, 102c can implement radio technologies such as Evolved UMTS Terrestrial Radio Access (E-UTRA), which can establish air interface 116 using Long Term Evolution (LTE) and / or LTE Advanced (LTE-A) and / or LTE Advanced Pro (LTE-A Pro).

[0036] In the embodiment, base station 114a and WTRUs 102a, 102b, 102c can implement radio technologies such as NR radio access, which can establish air interface 116 using new radio (NR).

[0037] In the embodiments, base station 114a and WTRUs 102a, 102b, and 102c can implement multiple radio access technologies. For example, base station 114a and WTRUs 102a, 102b, and 102c can, for instance, use the dual connectivity (DC) principle to implement both LTE and NR radio access together. Therefore, the air interface utilized by WTRUs 102a, 102b, and 102c can be characterized by multiple types of radio access technologies and / or transmissions sent to / from multiple types of base stations (e.g., eNBs and gNBs).

[0038] In other embodiments, base station 114a and WTRUs 102a, 102b, 102c can implement radio technologies such as IEEE 802.11 (i.e., Wi-Fi), IEEE 802.16 (i.e., Global Microwave Access Interoperability (WiMAX)), CDMA2000, CDMA2000 1X, CDMA2000 EV-DO, Provisional Standard 2000 (IS-2000), Provisional Standard 95 (IS-95), Provisional Standard 856 (IS-856), Global System for Mobile Communications (GSM), Enhanced GSM Evolution Data Rate (EDGE), GSM EDGE (GERAN), etc.

[0039] Figure 1A Base station 114b can be, for example, a wireless router, a home Node B, a home eNode B, or an access point, and can utilize any suitable RAT to facilitate wireless connectivity in a local area, such as a business premises, residence, vehicle, campus, industrial facility, air corridor (e.g., for drone use), road, etc. In one embodiment, base station 114b and WTRUs 102c, 102d can implement radio technologies such as IEEE 802.11 to establish a wireless local area network (WLAN). In another embodiment, base station 114b and WTRUs 102c, 102d can implement radio technologies such as IEEE 802.15 to establish a wireless personal area network (WPAN). In yet another embodiment, base station 114b and WTRUs 102c, 102d can utilize cellular-based RATs (e.g., WCDMA, CDMA2000, GSM, LTE, LTE-A, LTE-A Pro, NR, etc.) to establish picocells or femtocells. Figure 1A As shown, base station 114b can have a direct connection to Internet 110. Therefore, it is not required that base station 114b access Internet 110 via CN106 / 115.

[0040] RAN 104 / 113 can communicate with CN 106 / 115, which can be any type of network configured to provide voice, data, application, and / or Voice over Internet Protocol (VoIP) services to one or more of WTRU 102a, 102b, 102c, and 102d. Data can have varying Quality of Service (QoS) requirements, such as different throughput requirements, latency requirements, fault tolerance requirements, reliability requirements, data throughput requirements, mobility requirements, etc. CN 106 / 115 can provide call control, billing services, location-based services, prepaid calling, internet connectivity, video distribution, etc., and / or implement advanced security functions such as user authentication. Although not explicitly stated... Figure 1AAs shown, but will be understood, RAN 104 / 113 and / or CN 106 / 115 can communicate directly or indirectly with other RANs that use the same RAT as RAN 104 / 113 or a different RAT. For example, in addition to connecting to RAN 104 / 113, which may be using NR radio technology, CN 106 / 115 can also communicate with another RAN (not shown) using GSM, UMTS, CDMA2000, WiMAX, E-UTRA, or WiFi radio technology.

[0041] CN 106 / 115 can also serve as a gateway for WTRU 102a, 102b, 102c, 102d to access PSTN 108, the Internet 110, and / or other networks 112. PSTN 108 may include a circuit-switched telephone network providing Common Old-Style Telephone Service (POTS). The Internet 110 may include a global system of interconnected computer networks and devices using common communication protocols such as Transmission Control Protocol (TCP), User Datagram Protocol (UDP), and / or Internet Protocol (IP) from the TCP / IP Internet Protocol suite. Network 112 may include wired and / or wireless communication networks owned and / or operated by other service providers. For example, network 112 may include another CN connected to one or more RANs that may employ the same RAT as or a different RAT than RAN 104 / 113.

[0042] Some or all of the WTRUs 102a, 102b, 102c, and 102d in communication system 100 may include multi-mode capabilities (e.g., WTRUs 102a, 102b, 102c, and 102d may include multiple transceivers for communicating with different wireless networks via different wireless links). For example, Figure 1A The WTRU102c shown can be configured to communicate with base station 114a, which may employ cellular-based radio technology, and with base station 114b, which may employ IEEE 802 radio technology.

[0043] Figure 1B The following diagram illustrates the system of example WTRU 102. Figure 1B As shown, among other things, WTRU 102 may include a processor 118, a transceiver 120, a transmit / receive element 122, a speaker / microphone 124, a keypad 126, a display / touchpad 128, non-removable memory 130, removable memory 132, a power supply 134, a Global Positioning System (GPS) chipset 136, and / or other peripheral devices 138. It will be appreciated that WTRU 102 may include any sub-combination of the foregoing elements while remaining consistent with the embodiments.

[0044] Processor 118 can be a general-purpose processor, a special-purpose processor, a conventional processor, a digital signal processor (DSP), multiple microprocessors, one or more microprocessors associated with a DSP core, a controller, a microcontroller, an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA) circuit, any other type of integrated circuit (IC), a state machine, etc. Processor 118 can perform signal encoding / decoding, data processing, power control, input / output processing, and / or any other functions that enable WTRU 102 to operate in a wireless environment. Processor 118 can be coupled to transceiver 120, and transceiver 120 can be coupled to transmitting / receiving element 122. Although... Figure 1B The processor 118 and transceiver 120 are depicted as separate components, but it will be understood that the processor 118 and transceiver 120 can be integrated together into an electronic package or chip.

[0045] Transmitting / receiving element 122 can be configured to transmit signals to or receive signals from a base station (e.g., base station 114a) via air interface 116. For example, in one embodiment, transmitting / receiving element 122 can be an antenna configured to transmit and / or receive RF signals. In another embodiment, transmitting / receiving element 122 can be a transmitter / detector configured to transmit and / or receive, for example, IR, UV, or visible light signals. In yet another embodiment, transmitting / receiving element 122 can be configured to transmit and / or receive both RF signals and optical signals. It will be appreciated that transmitting / receiving element 122 can be configured to transmit and / or receive any combination of wireless signals.

[0046] Although the transmitting / receiving element 122 is in Figure 1B While depicted as a single element, WTRU 102 may include any number of transmit / receive elements 122. More specifically, WTRU 102 may employ MIMO technology. Thus, in one embodiment, WTRU 102 may include two or more transmit / receive elements 122 (e.g., multiple antennas) for transmitting and receiving wireless signals via air interface 116.

[0047] Transceiver 120 can be configured to modulate signals to be transmitted by transmitting / receiving element 122 and demodulate signals to be received by transmitting / receiving element 122. As noted above, WTRU 102 can have multi-mode capability. Therefore, transceiver 120 can include multiple transceivers for enabling WTRU 102 to communicate via various RATs such as NR and IEEE 802.11, for example.

[0048] The processor 118 of WTRU 102 can be coupled to a speaker / microphone 124, a keypad 126, and / or a display / touchpad 128 (e.g., a liquid crystal display (LCD) unit or an organic light-emitting diode (OLED) display unit), and can receive user input data from these devices. The processor 118 can also output user data to the speaker / microphone 124, keypad 126, and / or display / touchpad 128. Furthermore, the processor 118 can access information from any type of suitable memory and store the data in memory such as non-removable memory 130 and / or removable memory 132. 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. Removable memory 132 may include a subscriber identity module (SIM) card, memory stick, secure digital storage (SD) card, etc. In other embodiments, the processor 118 can access information from memory that is not physically located on WTRU 102 (such as on a server or home computer (not shown)) and store the data in that memory.

[0049] The processor 118 can receive power from the power supply 134 and can be configured to distribute and / or control power to other components in the WTRU 102. The power supply 134 can be any suitable device for powering the WTRU 102. For example, the power supply 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 cell units, fuel cell units, etc.

[0050] 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 instead of, information from the GPS chipset 136, the WTRU 102 may receive location information from base stations (e.g., base stations 114a, 114b) via the air interface 116, and / or determine its location based on the timing of signals received from two or more nearby base stations. It will be understood that the WTRU 102 may obtain location information using any suitable location determination method, while remaining consistent with the embodiments.

[0051] The processor 118 may be further coupled to other peripheral devices 138, which may include one or more software and / or hardware modules providing additional features, functions, and / or wired or wireless connectivity. For example, peripheral devices 138 may include accelerometers, electronic compasses, satellite transceivers, digital cameras (for photos and / or video), Universal Serial Bus (USB) ports, vibration devices, television transceivers, hands-free headsets, Bluetooth® modules, FM radio units, digital music players, media players, video game player modules, internet browsers, virtual reality and / or augmented reality (VR / AR) devices, activity trackers, etc. Peripheral devices 138 may include one or more sensors, which may be one or more of the following: gyroscopes, accelerometers, Hall effect sensors, magnetometers, orientation sensors, proximity sensors, temperature sensors, time sensors; geolocation sensors; altimeters, light sensors, touch sensors, magnetometers, barometers, gesture sensors, biometric sensors, and / or humidity sensors.

[0052] WTRU 102 may include a full-duplex radio, for which the transmission and reception of some or all signals (e.g., associated with a specific subframe of both UL (e.g., for transmission) and downlink (e.g., for reception)) may be concurrent and / or simultaneous. The full-duplex radio may include an interference management unit to reduce and / or substantially eliminate self-interference via hardware (e.g., a choke) or via signal processing (e.g., a separate processor (not shown) or via processor 118). In embodiments, WTRU 102 may include a half-duplex radio, for which the transmission and reception of some or all signals (e.g., associated with a specific subframe of either UL (e.g., for transmission) or downlink (e.g., for reception) may be concurrent and / or simultaneous.

[0053] Figure 1C The diagram illustrates a system diagram of RAN 104 and CN 106 according to an embodiment. As noted above, RAN 104 may employ E-UTRA radio technology to communicate with WTRUs 102a, 102b, and 102c via air interface 116. RAN 104 may also communicate with CN 106.

[0054] RAN 104 may include eNode-Bs 160a, 160b, and 160c, but will be appreciated that RAN 104 may include any number of eNode-Bs while remaining consistent with the embodiments. Each of eNode-Bs 160a, 160b, and 160c may include one or more transceivers for communicating with WTRUs 102a, 102b, and 102c via air interface 116. In one embodiment, eNode-Bs 160a, 160b, and 160c may implement MIMO technology. Thus, for example, eNode-B 160a may use multiple antennas to transmit radio signals to and / or receive radio signals from WTRU 102a.

[0055] Each of the eNode-B 160a, 160b, and 160c can be associated with a specific cell (not shown) and can be configured to handle radio resource management decisions, handover decisions, user scheduling in UL and / or DL, etc. Figure 1C As shown, eNode-B 160a, 160b, and 160c can communicate with each other via the X2 interface.

[0056] Figure 1C The CN 106 shown 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 is depicted as part of the CN 106, it will be understood that any of these elements may be owned and / or operated by an entity other than the CN operator.

[0057] The MME 162 can connect to each of the eNode-Bs 162a, 162b, and 162c in RAN 104 via the S1 interface and can be used as a control node. For example, the MME 162 can be responsible for authenticating users of WTRUs 102a, 102b, and 102c, bearer activation / deactivation, selecting a specific serving gateway during the initial attachment of WTRUs 102a and 102c, etc. The MME 162 can provide control plane functions for handover between RAN 104 and other RANs (not shown) employing other radio technologies such as GSM and / or WCDMA.

[0058] The SGW 164 can connect to each eNode B 160a, 160b, or 160c in RAN 104 via the S1 interface. The SGW 164 can typically route user data packets to or forward user data packets from WTRUs 102a, 102b, or 102c. The SGW 164 can also perform other functions, such as anchoring the user plane during inter-eNode B handover, triggering paging when DL data is available for WTRUs 102a, 102b, or 102c, and managing and storing the context of WTRUs 102a, 102b, or 102c.

[0059] The SGW 164 can connect to the PGW 166, which can provide WTRU 102a, 102b, and 102c with access to packet-switched networks such as Internet 110, facilitating communication between WTRU 102a, 102b, 102c and IP-enabled devices.

[0060] CN 106 can facilitate communication with other networks. For example, CN 106 can provide WTRU 102a, 102b, and 102c with access to circuit-switched networks such as PSTN 108 to facilitate communication between WTRU 102a, 102b, and 102c and traditional landline communication equipment. For example, CN 106 may include, or be able to communicate with, an IP gateway (e.g., an IP Multimedia Subsystem (IMS) server) serving as an interface between CN 106 and PSTN 108. Furthermore, CN 106 can provide WTRU 102a, 102b, and 102c with access to other networks 112, which may include other wired and / or wireless networks owned and / or operated by other service providers.

[0061] Despite WTRU in Figures 1A-1D While described as a wireless terminal, it is conceivable that in some representative embodiments, such a terminal may (e.g., temporarily or permanently) use a wired communication interface with a communication network.

[0062] In a representative embodiment, the other network 112 may be a WLAN.

[0063] A WLAN in Infrastructure Basic Services 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 access or an interface to a distribution system (DS) or another type of wired / wireless network that introduces and / or leads traffic into and / or out of the BSS. Traffic originating outside the BSS and destined for a STA can be delivered to the AP. Traffic originating from a STA and destined for a destination outside the BSS can be sent to the AP for delivery to its respective destination. Traffic between STAs within the BSS can be sent, for example, through the AP, where a source STA can send traffic to the AP, and the AP can deliver the traffic to the destination STA. Traffic between STAs within the BSS can be considered and / or referred to as peer-to-peer traffic. Peer-to-peer traffic can be sent between the source STA and the destination STA (e.g., directly between them) using a direct link setup (DLS). In some representative embodiments, the DLS may use 802.11e DLS or 802.11z tunneled DLS (TDLS). A WLAN using the Standalone BSS (IBSS) mode may not have an access point (AP), and STAs within the IBSS or using the IBSS (e.g., all STAs) can communicate directly with each other. The IBSS communication mode may sometimes be referred to as the "ad-hoc" communication mode in this document.

[0064] When operating in 802.11ac infrastructure mode or a similar mode, the AP can transmit beacons on a fixed channel, such as the primary channel. The primary channel can be of fixed width (e.g., a 20 MHz bandwidth) or dynamically set via signaling. The primary channel can be the operating channel of the BSS and can be used by the STA to establish a connection with the AP. In some representative embodiments, such as in an 802.11 system, Carrier Sense Multiple Access (CSMA / CA) with collision avoidance can be implemented. For CSMA / CA, each STA (e.g., every STA), including the AP, can sense the primary channel. If a particular STA senses / detects and / or determines that the primary channel is busy, that particular STA can exit. A single STA (e.g., only one station) can transmit at any given time within a given BSS.

[0065] High-throughput (HT) STAs can communicate using a 40 MHz wide channel, for example, by combining a primary 20 MHz channel with adjacent or non-adjacent 20 MHz channels to form a 40 MHz wide channel.

[0066] Very High Throughput (VHT) STAs can support channels with widths of 20 MHz, 40 MHz, 80 MHz, and / or 160 MHz. A 40 MHz and / or 80 MHz channel can be formed by combining consecutive 20 MHz channels. A 160 MHz channel can be formed by combining eight consecutive 20 MHz channels, or by combining two non-consecutive 80 MHz channels (this can be referred to as an 80+80 configuration). For the 80+80 configuration, after channel coding, data is passed through a segmented parser that splits the data into two streams. Inverse Fast Fourier Transform (IFFT) processing and time-domain processing can be performed on each stream separately. The streams can be mapped onto the two 80 MHz channels, and the data can be transmitted by the transmitting STA. At the receiver of the receiving STA, the operation of the 80+80 configuration can be reversed, and the combined data can be sent to the Media Access Control (MAC).

[0067] 802.11af and 802.11ah support operating modes below 1 GHz. The channel operating bandwidth and carrier in 802.11af and 802.11ah are reduced compared to those used in 802.11n and 802.11ac. 802.11af supports 5 MHz, 10 MHz, and 20 MHz bandwidths in the TV whitespace (TVWS) spectrum, while 802.11ah uses non-TVWS spectrum to support 1 MHz, 2 MHz, 4 MHz, 8 MHz, and 16 MHz bandwidths. According to a representative embodiment, 802.11ah can support instrument-type control / machine-type communication, such as MTC devices in macro coverage areas. MTC devices may have certain capabilities, such as limited capabilities, including support (e.g., only support) certain and / or limited bandwidths. MTC devices may include batteries with a battery life exceeding a threshold (e.g., to maintain a very long battery life).

[0068] WLAN systems that can support multiple channels and channel bandwidths, such as 802.11n, 802.11ac, 802.11af, and 802.11ah, include channels that can be designated as the primary channel. The primary channel can have a bandwidth equal to the maximum common operating bandwidth supported by all STAs in the BSS. The bandwidth of the primary channel can be set and / or limited by the STAs supporting the minimum bandwidth operating mode from all STAs operating in the BSS. In the example of 802.11ah, for STAs supporting (e.g., only supporting) the 1 MHz mode (e.g., MTC type devices), the primary channel can still be 1 MHz wide even if the AP and other STAs in the BSS support 2 MHz, 4 MHz, 8 MHz, 16 MHz, and / or other channel bandwidth operating modes. Carrier sensing and / or Network Allocation Vector (NAV) settings may depend on the status of the primary channel. If the primary channel is busy, for example, due to STAs (which only support the 1 MHz operating mode) transmitting to the AP, the entire available band may be considered busy even if most of the band remains idle and may be available.

[0069] In the United States, the available frequency band for 802.11ah is 902 MHz to 928 MHz. In South Korea, the available frequency band is from 917.5 MHz to 923.5 MHz. In Japan, the available frequency band is from 916.5 MHz to 927.5 MHz. Depending on the country code, the total bandwidth available for 802.11ah ranges from 6 MHz to 26 MHz.

[0070] Figure 1D The diagram illustrates a system diagram of RAN 113 and CN 115 according to an embodiment. As noted above, RAN 113 can use NR radio technology to communicate with WTRUs 102a, 102b, and 102c via air interface 116. RAN 113 can also communicate with CN 115.

[0071] RAN 113 may include gNBs 180a, 180b, and 180c; however, it will be understood that RAN 113 may include any number of gNBs while remaining consistent with the embodiments. Each of gNBs 180a, 180b, and 180c may include one or more transceivers for communicating with WTRUs 102a, 102b, and 102c via air interface 116. In one embodiment, gNBs 180a, 180b, and 180c may implement MIMO technology. For example, gNBs 180a and 180b may utilize beamforming to transmit signals to and / or receive signals from gNBs 180a, 180b, and 180c. Thus, for example, gNB 180a may use multiple antennas to transmit radio signals to and / or receive radio signals from WTRU 102a. In an embodiment, gNBs 180a, 180b, and 180c may implement carrier aggregation technology. For example, gNB 180a can transmit multiple component carriers to WTRU 102a (not shown). A subset of these component carriers may be located on unlicensed spectrum, while the remaining component carriers may be located on licensed spectrum. In embodiments, gNBs 180a, 180b, and 180c can implement Coordinated Multipoint (CoMP) technology. For example, WTRU 102a can receive coordinated transmissions from gNBs 180a and 180b (and / or gNB 180c).

[0072] WTRUs 102a, 102b, and 102c can communicate with gNBs 180a, 180b, and 180c using transmissions associated with Scalable Digital Numerology (SDN). For example, OFDM symbol spacing and / or OFDM subcarrier spacing can vary for different transmissions, different cells, and / or different portions of the radio transmission spectrum. WTRUs 102a, 102b, and 102c can communicate with gNBs 180a, 180b, and 180c using subframes of various or scalable lengths or Transmission Time Intervals (TTIs) (e.g., containing different numbers of OFDM symbols and / or absolute times of varying durations).

[0073] gNBs 180a, 180b, and 180c can be configured to communicate with WTRUs 102a, 102b, and 102c in standalone and / or non-standalone configurations. In standalone configuration, WTRUs 102a, 102b, and 102c can communicate with gNBs 180a, 180b, and 180c without also accessing other RANs (e.g., eNode-Bs 160a, 160b, and 160c). In standalone configuration, WTRUs 102a, 102b, and 102c can utilize one or more of gNBs 180a, 180b, and 180c as mobility anchors. In standalone configuration, WTRUs 102a, 102b, and 102c can communicate with gNBs 180a, 180b, and 180c using signals in unlicensed frequency bands. In a non-standalone configuration, WTRUs 102a, 102b, and 102c can communicate / connect with gNBs 180a, 180b, and 180c, and also with another RAN such as eNode-Bs 160a, 160b, and 160c. For example, WTRUs 102a, 102b, and 102c can implement DC principles to communicate essentially simultaneously with one or more gNBs 180a, 180b, and 180c and one or more eNode-Bs 160a, 160b, and 160c. In a non-standalone configuration, eNode-Bs 160a, 160b, and 160c can act as mobility anchors for WTRUs 102a, 102b, and 102c, and gNBs 180a, 180b, and 180c can provide additional coverage and / or throughput to serve WTRUs 102a, 102b, and 102c.

[0074] Each of gNBs 180a, 180b, and 180c can be associated with a specific cell (not shown) and can be configured to handle radio resource management decisions, handover decisions, user scheduling in UL and / or DL, network slicing support, dual connectivity, interoperability between NR and E-UTRA, routing of user plane data to User Plane Functions (UPF) 184a and 184b, and routing of control plane information to Access and Mobility Management Functions (AMF) 182a and 182b, etc. Figure 1D As shown, gNB 180a, 180b, and 180c can communicate with each other via the Xn interface.

[0075] Figure 1DThe CN 115 shown 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 is depicted as part of the CN 115, it will be understood that any of these elements may be owned and / or operated by an entity other than the CN operator.

[0076] AMF 182a and 182b can connect to one or more of gNBs 180a, 180b, and 180c in RAN 113 via the N2 interface and can be used as control nodes. For example, AMF 182a and 182b can be responsible for authenticating users of WTRU 102a, 102b, and 102c, supporting network slicing (e.g., handling different PDU sessions with different requirements), selecting specific SMF183a and 183b, managing registration areas, terminating NAS signaling, mobility management, etc. AMF 182a and 182b can use network slicing to customize CN support for WTRU 102a, 102b, and 102c based on the service types being utilized by WTRU 102a, 102b, and 102c. For example, different network slices can 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, and services for Machine Type Communication (MTC) access. AMF 162 can provide control plane functions for handover between RAN 113 and other RANs (not shown) employing other radio technologies such as LTE, LTE-A, LTE-A Pro, and / or non-3GPP access technologies such as WiFi.

[0077] SMFs 183a and 183b can connect to AMFs 182a and 182b in CN 115 via the N11 interface. SMFs 183a and 183b can also connect to UPFs 184a and 184b in CN 115 via the N4 interface. SMFs 183a and 183b can select and control UPFs 184a and 184b, and configure the routing of traffic through UPFs 184a and 184b. SMFs 183a and 183b can perform other functions, such as managing and allocating UE IP addresses, managing PDU sessions, controlling policy enforcement and QoS, and providing downlink data notifications. PDU session types can be IP-based, non-IP-based, or Ethernet-based.

[0078] UPF 184a and 184b can connect to one or more of gNB 180a, 180b, and 180c in RAN 113 via the N3 interface. The N3 interface can provide WTRU 102a, 102b, and 102c with access to packet-switched networks such as Internet 110, facilitating communication between WTRU 102a, 102b, and 102c and IP-enabled devices. UPF 184 and 184b can 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, and providing mobility anchoring.

[0079] CN 115 can facilitate communication with other networks. For example, CN 115 may include, or be able to communicate with, an IP gateway (e.g., an IP Multimedia Subsystem (IMS) server) serving as an interface between CN 115 and PSTN 108. Furthermore, CN 115 can provide WTRUs 102a, 102b, and 102c with access to other networks 112, which may include other wired and / or wireless networks owned and / or operated by other service providers. In one embodiment, WTRUs 102a, 102b, and 102c may be connected to local data networks (DNs) 185a and 185b via the N3 interface to UPFs 184a and 184b and the N6 interface between UPFs 184a and 184b and DNs 185a and 185b.

[0080] Given Figures 1A-1D as well as Figures 1A-1D The corresponding descriptions herein indicate that one or more of the functions described herein in relation to one or more of the following can be implemented by one or more emulation devices (not shown): WTRU 102a-102d, base station 114a-114b, eNode-b 160a-160c, MME 162, SGW 164, PGW 166, gNB 180a-180c, AMF 182a-182b, UPF 184a-184b, SMF 183a-183b, DN 185a-185b, and / or any other device(s) described herein. An emulation device can be one or more devices configured to emulate one or more of the functions described herein. For example, an emulation device can be used to test other devices and / or simulate network and / or WTRU functions.

[0081] Simulation devices can be designed to perform one or more tests on other devices in laboratory and / or carrier network environments. For example, one or more simulation devices can perform one or more functions while being fully or partially implemented and / or deployed as part of a wired and / or wireless communication network to test other devices within the communication network. One or more simulation devices can perform one or more functions while being temporarily implemented / deployed as part of a wired or wireless communication network. Simulation devices can be directly coupled to another device for testing purposes and / or can be used for testing via over-the-air wireless communication.

[0082] One or more simulation devices can perform one or more functions without being implemented / deployed as part of a wired and / or wireless communication network. For example, simulation devices can be used in test scenarios within test laboratories and / or undeployed (e.g., testing) wired and / or wireless communication networks to perform testing of one or more components. One or more simulation devices can be test rigs. Simulation devices can transmit and / or receive data using direct RF coupling and / or wireless communication via RF circuitry (e.g., which may include one or more antennas).

[0083] This application describes a wide variety of aspects, including tools, features, examples, models, methods, etc. Many of these aspects are described in a targeted manner and, at least to show individual characteristics, are generally described in a way that may sound restrictive. However, this is for clarity and does not limit the application or scope of those aspects. In fact, all the different aspects can be combined and interchanged to provide other aspects. Furthermore, these aspects can also be combined and interchanged with aspects described in earlier applications.

[0084] The aspects described and envisioned in this application can be implemented in many different forms. Figures 5-18 Some examples can be provided, but other examples are also envisioned. Figures 5-18 The discussion does not limit the breadth of implementations. At least one of these aspects generally relates to video encoding and decoding, and at least one other aspect generally relates to the transmission of the generated or encoded bitstream. These and other aspects can be implemented as methods, apparatus, computer-readable storage media having instructions stored thereon for encoding or decoding video data according to any of the described methods, and / or computer-readable storage media having bitstreams generated according to any of the described methods stored thereon.

[0085] In this application, the terms “reconstruction” and “decoding” are used interchangeably, the terms “pixel” and “sample” are used interchangeably, and the terms “image”, “picture” and “frame” are used interchangeably.

[0086] This document describes various methods, each of which includes one or more steps or actions to achieve the described method. Unless a specific order of steps or actions is required for the method to operate correctly, the order and / or use of specific steps and / or actions can be modified or combined. Furthermore, terms such as "first," "second," etc., can be used in various examples to modify elements, components, steps, operations, etc., such as "first decoding" and "second decoding," for example. Unless specifically required, the use of such terms does not imply a reordering of the modified operations. Therefore, in this example, the first decoding does not need to be performed before the second decoding and can occur, for example, before, during, or within a time period overlapping with the second decoding.

[0087] The various methods and other aspects described in this application can be used to modify modules (e.g., decoding modules) of the video encoder 200 and video decoder 300, such as... Figure 2 and Figure 3 As shown. Furthermore, the subject matter disclosed herein can be applied to, for example, any type, format, or version of video codecs, whether described in pre-existing or future-developed standards or recommendations, and any extensions to such standards and recommendations. Unless otherwise indicated or technically excluded, the aspects described in this application may be used alone or in combination.

[0088] Various numerical values ​​are used in the examples described in this application, such as chroma format (e.g., 4:2:0, 4:2:2, 4:4:4), bit depth, coefficient values, constant values, number of filters (e.g., 16 CCALF filters), block / CTU size (e.g., 64x64, 128x128, or 256x256 pixels), luma block size (e.g., 2x2, 4x4), filter size (e.g., 7x7 diamond filter for luma, 5x5 diamond filter for chroma, 9x9 filter), multiplier, transform size (e.g., 64), number of sub-codec units, sub-codec unit size, etc. These and other specific values ​​are used only for illustrative purposes, and the aspects described are not limited to these specific values.

[0089] Figure 2 A diagram illustrating an example video encoder (e.g., a block-based hybrid video encoder) is provided. Variations of the example encoder 200 are envisioned, but for clarity, encoder 200 is described below without depicting all anticipated variations.

[0090] Before being encoded, the video sequence can undergo pre-coding (201), for example, applying color transformations to the input color image (e.g., converting from RGB 4:4:4 to YCbCr 4:2:0), or remapping the input image components to obtain a more resilient signal distribution to compression (e.g., using histogram equalization of one of the color components). Metadata can be associated with pre-processing and attached to the bitstream.

[0091] In encoder 200, the image is encoded by encoder elements as described below. The image to be encoded is partitioned (202) and processed in units such as codec units (CUs). Each unit is encoded using, for example, an intra-frame or inter-frame mode. When a unit is encoded intra-frame, it performs intra-frame prediction (260). In inter-frame mode, motion estimation (275) and compensation (270) are performed. The encoder determines (205) which of the intra-frame or inter-frame modes to use to encode the unit and indicates the intra-frame / inter-frame decision by, for example, a prediction mode flag. For example, the prediction residual is calculated by subtracting (210) the predicted block from the original image block.

[0092] The predicted residual is then transformed (225) and quantized (230). The quantized transform coefficients, along with motion vectors and other syntax elements (such as image partitioning information), are entropy encoded (245) to output a bitstream. The encoder can skip this transform and apply quantization directly to the untransformed residual signal. The encoder can bypass both the transform and quantization, meaning the residual is directly encoded without applying either the transform or quantization process.

[0093] The encoder decodes the encoded block to provide a reference for further prediction. The quantized transform coefficients are dequantized (240) and inversely transformed (250) to decode the prediction residual. The decoded prediction residual and the predicted block are combined (255) to reconstruct the image block. An in-loop filter (265) is applied to the reconstructed image to perform, for example, deblocking / SAO (Sample Adaptive Shift) / ALF (Adaptive Loop Filtering) filtering to reduce coding artifacts. The filtered image is stored in a reference image buffer (280).

[0094] Figure 3 This diagram illustrates an example of a video decoder. In the example decoder 300, as described below, the bitstream is decoded by decoder elements. The video decoder 300 is typically implemented as follows... Figure 2 The encoder 200 is the inverse of the decoder pass described in the document. The encoder 200 typically also performs video decoding as part of the encoding of the video data.

[0095] Specifically, the input to the decoder includes a video bitstream, which can be generated by the video encoder 200. The bitstream is first entropy decoded (330) to obtain transform coefficients, prediction modes, motion vectors, and other encoding / decoding information. Picture partitioning information indicates how to partition the picture. Therefore, the decoder can partition the picture according to the decoded picture partitioning information (335). The transform coefficients are dequantized (340) and inverse transformed (350) to decode the prediction residuals. The decoded prediction residuals and the predicted blocks are combined (355) to reconstruct the image blocks. The predicted blocks can be obtained from intra-frame prediction (360) or motion-compensated prediction (i.e., inter-frame prediction) (375) (370). An in-loop filter (365) is applied to the reconstructed image. The filtered image is stored in a reference picture buffer (380). In some examples (e.g., for a given picture), the contents of the reference picture buffer 380 on the decoder 300 side may be the same as the contents of the reference picture buffer 280 on the encoder 200 side (e.g., for the same picture).

[0096] The decoded image can also undergo post-decoding processing (385), such as inverse color transformation (e.g., from YCbCr 4:2:0 to RGB 4:4:4) or inverse remapping of the remapping process performed in pre-encoding processing (201). Post-decoding processing can use metadata derived in pre-encoding processing and signaled in the bitstream. In the example, the decoded image (e.g., after applying an in-loop filter (365) and / or after post-decoding processing (385) if post-decoding processing is used) can be sent to a display device for rendering to the user.

[0097] Figure 4 The diagram illustrates examples of systems in which the various aspects and examples described herein may be implemented. System 400 may be embodied as a device including the various components described below and configured to implement one or more aspects described in this document. Examples of such devices include, but are not limited to, various electronic devices such as personal computers, laptops, smartphones, tablets, digital multimedia set-top boxes, digital television receivers, personal video recording systems, connected home appliances, and servers. Elements of system 400 may be embodied individually or in combination 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, system 400 is communicatively coupled to one or more other systems or other electronic devices via, for example, a communication bus or through dedicated input and / or output ports. In various examples, system 400 is configured to implement one or more aspects described in this document.

[0098] System 400 includes at least one processor 410 configured to execute instructions loaded thereon to implement various aspects, such as those described in this document. Processor 410 may include embedded memory, input / output interfaces, and various other circuitry known in the art. System 400 includes at least one memory 420 (e.g., a volatile memory device and / or a non-volatile memory device). System 400 includes a storage device 440, which may include non-volatile memory and / or volatile memory, including but not limited to electrically erasable programmable read-only memory (EEPROM), read-only memory (ROM), programmable read-only memory (PROM), random access memory (RAM), dynamic random access memory (DRAM), static random access memory (SRAM), flash memory, disk drives, and / or optical disk drives. As a non-limiting example, storage device 440 may include internal storage devices, attached storage devices (including removable and non-removable storage devices), and / or network-accessible storage devices.

[0099] System 400 includes an encoder / decoder module 430 configured to, for example, process data to provide encoded or decoded video, and the encoder / decoder module 430 may include its own processor and memory. The encoder / decoder module 430 represents one or more modules that can be included in a device to perform encoding and / or decoding functions. It is well known that a device may include one or both encoding and decoding modules. Additionally, as those skilled in the art will appreciate, the encoder / decoder module 430 may be implemented as a separate element of system 400, or may be incorporated into processor 410 as a combination of hardware and software.

[0100] Program code to be loaded onto processor 410 or encoder / decoder 430 to implement 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. According to various examples, one or more of processor 410, memory 420, storage device 440, and encoder / decoder module 430 may store one or more various items during the execution of the processes described in this document. Such stored items may include, but are not limited to, input video, decoded video or portions of decoded video, bitstreams, matrices, variables, and intermediate or final results from the processing of equations, formulas, operations, and operational logic.

[0101] In some examples, the memory within processor 410 and / or encoder / decoder module 430 is used to store instructions and provide working memory for processing required during encoding or decoding. However, in other examples, external memory (e.g., the processing device could be processor 410 or encoder / decoder module 430) is used for one or more of these functions. External memory could be memory 420 and / or storage device 440, such as volatile memory and / or non-volatile flash memory. In several examples, external non-volatile flash memory is used to store, for example, the operating system of a television. In at least one example, fast external volatile memory (such as RAM) is used as working memory for video encoding and decoding operations.

[0102] Inputs to the components of system 400 may be provided by various input devices as indicated in box 445. Such input devices include, but are not limited to: (i) a radio frequency (RF) section that receives, for example, RF signals transmitted 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. Figure 4 Other examples not shown include composite video.

[0103] In various examples, the input device of block 445 has associated corresponding input processing elements known in the art. For example, the RF section may be associated with elements suitable for: (i) selecting a desired frequency (also known as selecting a signal, or limiting a signal band to a certain band); (ii) down-converting the selected signal; (iii) band-limiting it again to a narrower band to select, for example, a signal band that may be referred to as a channel in some examples; (iv) demodulating the down-converted and band-limited signal; (v) performing error correction; and / or (vi) demultiplexing to select a desired data packet stream. The RF section of various examples includes one or more elements for performing these functions, such as frequency selectors, signal selectors, band limiters, channel selectors, filters, downconverters, demodulators, error correctors, and demultiplexers. The RF section may include tuners that perform various of these functions, including, for example, down-converting a received signal to a lower frequency (e.g., intermediate frequency or near-baseband frequency) or baseband. In one set-top box example, the RF section and its associated input processing elements receive RF signals transmitted via a wired (e.g., cable) medium and perform frequency selection by filtering, down-converting, and re-filtering to the desired frequency band. Various examples rearrange the order of the above (and other) components, remove some of these components, and / or add other components that perform similar or different functions. Adding components may include inserting components between existing components, such as, for example, inserting amplifiers and analog-to-digital converters. In various examples, the RF section includes an antenna.

[0104] USB and / or HDMI terminals may include corresponding 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, such as Reed-Solomon error correction, may be implemented as needed, for example, within a separate input processing IC or within processor 410. Similarly, aspects of USB or HDMI interface processing may be implemented as needed within a separate interface IC or within processor 410. Demodulated, error-corrected, and demultiplexed streams are provided to various processing elements, including, for example, processor 410 and encoder / decoder 430 operating in conjunction with memory and storage elements, to process the data streams as needed for presentation on an output device.

[0105] Various components of system 400 can be provided within an integrated housing. Within the integrated housing, the various components can be interconnected using a suitable connection arrangement 425 and data can be transmitted therebetween, such as internal buses known in the art, including inter-IC (I2C) buses, wiring, and printed circuit boards.

[0106] System 400 includes a communication interface 450 that enables communication with other devices via a communication channel 460. The communication interface 450 may include, but is not limited to, a transceiver configured to transmit and receive data via the communication channel 460. The communication interface 450 may include, but is not limited to, a modem or network interface card (NIC), and the communication channel 460 may be implemented, for example, within a wired and / or wireless medium.

[0107] In various examples, data is streamed or otherwise provided to system 400 using a wireless network such as Wi-Fi (e.g., IEEE 802.11 (IEEE refers to the Institute of Electrical and Electronics Engineers)). In these examples, the Wi-Fi signal is received via a communication channel 460 and a communication interface 450 suitable for Wi-Fi communication. The communication channel 460 in these examples is typically connected to an access point or router that provides access to external networks, including the Internet, to allow streaming applications and other over-the-top communications. Other examples use a set-top box to provide streaming data to system 400, delivering data via an HDMI connection in input box 445. Still other examples use an RF connection in input box 445 to provide streaming data to system 400. As shown above, various examples provide data in a non-streaming manner. Additionally, various examples use wireless networks other than Wi-Fi, such as cellular networks or Bluetooth® networks.

[0108] System 400 can provide output signals to various output devices, including displays 475, speakers 485, and other peripheral devices 495. Displays 475 in various examples include one or more of, for example, touchscreen displays, organic light-emitting diode (OLED) displays, curved displays, and / or foldable displays. Displays 475 can be used in televisions, tablets, laptops, mobile phones, or other devices. Displays 475 can also be integrated with other components (e.g., in smartphones) or standalone (e.g., as an external monitor for a laptop). In various examples, other peripheral devices 495 include one or more of standalone digital video discs (or digital multifunction discs) (DVDs, for both terms), disc players, stereo systems, and / or lighting systems. Various examples use one or more peripheral devices 495 that provide functionality based on the output of system 400. For example, a disc player performs the function of playing the output of system 400.

[0109] In various examples, signaling such as AV links, Consumer Electronics Control (CEC), or other communication protocols that enable device-to-device control with or without user intervention is used to transmit control signals between system 400 and display 475, speaker 485, or other peripheral devices 495. Output devices can be communicatively coupled to system 400 via dedicated connections through their respective interfaces 470, 480, and 490. Alternatively, output devices can be connected to system 400 via communication interface 450 using communication channel 460. Display 475 and speaker 485 can be integrated into a single unit with other components of system 400 in electronic devices such as, for example, televisions. In various examples, display interface 470 includes display drivers, such as, for example, timing controller (TCon) chips.

[0110] Alternatively, the display 475 and speaker 485 can be separated from one or more other components, for example, if the RF section of input 445 is part of a separate set-top box. In various examples where the display 475 and speaker 485 are external components, the output signal can be provided via dedicated output connections, including, for example, HDMI ports, USB ports, or COMP outputs.

[0111] The example can be implemented by computer software implemented by processor 410, or by hardware, or by a combination of hardware and software. As a non-limiting example, the example can be implemented by one or more integrated circuits. Memory 420 can be of any type suitable for the technical environment and can be implemented using any suitable data storage technology, such as optical memory devices, magnetic memory devices, semiconductor-based memory devices, fixed memory, and removable memory, as non-limiting examples. Processor 410 can be of any type suitable for the technical environment and, as a non-limiting example, can encompass one or more of microprocessors, general-purpose computers, special-purpose computers, and processors based on multi-core architectures.

[0112] Various implementations involve decoding. As used in this application, "decoding" can encompass all or part of a process, such as performing a received encoded sequence to produce a final output suitable for display. In various examples, such a process includes one or more processes typically performed by a decoder, such as entropy decoding, inverse quantization, inverse transform, and differential decoding. In various examples, such a process also includes, or alternatively includes, the process performed by the decoder of the various implementations described in this application, such as determining the slice associated with the current chroma CTB and encoding / decoding it in a separate tree mode, calculating the complete residual luminance block co-located with the current chroma CTB, deriving the co-located luminance block for the current chroma codec unit (CU) associated with the chroma CTB, obtaining an intra-frame reference sample associated with the co-located luminance block, obtaining an intra-frame prediction mode associated with the co-located luminance block, predicting the co-located luminance block based on the intra-frame reference sample and the intra-frame prediction mode, and calculating a luminance residual block, wherein the residual luminance block is calculated as the difference between the reconstructed luminance block and the predicted co-located luminance block, storing the calculated residual luminance block in the complete residual luminance block co-located with the current chroma CTB, and applying chroma ALF and CCALF to the calculated complete residual luminance block, etc.

[0113] As further examples, in one example, "decoding" refers only to entropy decoding; in another example, "decoding" refers only to differential decoding; and in yet another example, "decoding" refers to a combination of entropy decoding and differential decoding. It will be clear, and those skilled in the art, whether the phrase "decoding processing" is intended to specifically refer to a subset of operations or generally to broader decoding processing, based on the specific context of the description.

[0114] Various implementations involve encoding. Similar to the discussion of "decoding" above, the term "encoding" as used in this application can encompass all or part of a process performed on an input video sequence to produce an encoded bitstream. In various examples, such a process includes one or more processes typically performed by an encoder, such as partitioning, differential coding, transform, quantization, and entropy coding. In various examples, such a process also includes, or alternatively includes, the process performed by the encoders of the various implementations described in this application, such as determining the slice associated with the current chroma CTB and encoding / decoding it in a separate tree mode, calculating the complete residual luminance block co-located with the current chroma CTB, deriving the co-located luminance block for the current chroma codec unit (CU) associated with the chroma CTB, obtaining an intra-frame reference sample associated with the co-located luminance block, obtaining an intra-frame prediction mode associated with the co-located luminance block, predicting the co-located luminance block based on the intra-frame reference sample and the intra-frame prediction mode, and calculating a luminance residual block, wherein the residual luminance block is calculated as the difference between the reconstructed luminance block and the predicted co-located luminance block, storing the calculated residual luminance block in the complete residual luminance block co-located with the current chroma CTB, and applying the chroma ALF and CCALF to the calculated complete residual luminance block, etc.

[0115] As further examples, in one example, "encoding" refers only to entropy encoding; in another, "encoding" refers only to differential encoding; and in yet another, "encoding" refers to a combination of differential and entropy encoding. It will be clear, and those skilled in the art, whether the phrase "encoding processing" is intended to specifically refer to a subset of operations or generally to broader encoding processing, based on the specific context of the description.

[0116] When a diagram is presented as a flowchart, it should be understood that it also provides a block diagram of the corresponding device. Similarly, when a diagram is presented as a block diagram, it should be understood that it also provides a flowchart of the corresponding method / process.

[0117] The implementations and aspects described herein can be implemented, for example, in methods or processes, apparatuses, software programs, data streams, or signals. Even if discussed only in the context of a single implementation (e.g., discussed only as a method), the features under discussion can be implemented in other forms (e.g., apparatuses or programs). Apparatuses can be implemented, for example, in appropriate hardware, software, and firmware. Methods can be implemented, for example, in a processor, which generally refers to a processing device, including, for example, a computer, microprocessor, integrated circuit, or programmable logic device. Processors also include communication devices, such as, for example, computers, mobile phones, portable / personal digital assistants (“PDAs”), and other devices that facilitate information communication between end users.

[0118] The reference to "an example" or "example" or "an implementation" or "implementation" and its variations means that the specific features, structures, characteristics, etc., described in connection with the example are included in at least one example. Therefore, the phrases "in an example" or "in the example" or "in an implementation" or "in the implementation" and any other variations appearing throughout this application do not necessarily all refer to the same example.

[0119] Additionally, this application may involve "determining" various pieces of information. Determining information may include, for example, one or more of estimated information, calculated information, predicted information, or information retrieved from memory. Obtaining may include receiving, retrieving, constructing, generating, and / or determining.

[0120] Furthermore, this application may involve "accessing" various information fragments. Accessing information may include, for example, receiving information, retrieving information (e.g., from memory), storing information, moving information, copying information, calculating information, determining information, predicting information, or estimating information, or one or more of these.

[0121] Additionally, this application may relate to "receiving" various pieces of information. Like "access," receiving is intended to be a broad term. Receiving information may include, for example, accessing information or retrieving information (e.g., from memory) from one or more sources. Furthermore, "receiving" typically relates in one or more ways during operations such as, for example, storing information, processing information, transmitting information, moving information, copying information, erasing information, calculating information, determining information, predicting information, or estimating information.

[0122] To be clear, for example, in the cases of “A / B,” “A and / or B,” and “at least one of A and B,” the use of any of the following “ / ,” “and / or,” and “at least one of…” is intended to cover selecting only the first listed option (A), or only the second listed option (B), or both options (A and B). As another example, in the cases of “A, B, and / or C” and “at least one of A, B, and C,” this wording is intended to cover selecting only the first listed option (A), or only the second listed option (B), or only the third listed option (C), or only the first and second listed options (A and B), or only the first and third listed options (A and C), or only the second and third listed options (B and C), or all three options (A, B, and C). As will be apparent to those skilled in the art and related fields, this can be extended to as many items as are listed.

[0123] Furthermore, as used herein, the term "signal" refers, among other things, to something indicated to the corresponding decoder. Encoder signals may include, for example, residuals, offsets, filters, filter coefficients, flags, partition types, etc. In this way, in the examples, the same parameters are used on both the encoder and decoder sides. Thus, for example, the encoder may transmit (explicit signaling) a specific parameter to the decoder so that the decoder can use the same specific parameter. Conversely, if the decoder already has that specific parameter as well as other parameters, then signaling can then be used without transmission (implicit signaling) to simply allow the decoder to know and select that specific parameter. In various examples, bit savings are achieved by avoiding the transmission of any actual functionality. It should be understood that signaling can be done in a variety of ways. For example, in various examples, one or more syntax elements, flags, etc., are used to signal information to the corresponding decoder. Although the foregoing refers to the verb form of the term "signal," the term "signal" can also be used as a noun in this document.

[0124] It will be apparent to those skilled in the art that implementations can generate a wide variety of signals formatted to carry, for example, information that can be stored or transmitted. This information may include, for example, instructions for implementing a method or data generated by one of the described implementations. For example, a signal may be formatted to carry a bit stream as described in the example. Such a signal may be formatted, for example, as an electromagnetic wave (e.g., using the radio frequency portion of the spectrum) or a baseband signal. Formatting may include, for example, encoding a data stream and modulating a carrier wave with the encoded data stream. The information carried by the signal may be, for example, analog or digital information. It is well known that signals can be transmitted via a wide variety of wired or wireless links. Signals may be stored on, accessed from, or received from a processor-readable medium.

[0125] This document describes numerous examples. Features of the examples may be provided individually or in any combination across various claim classes and types. Furthermore, across various claim classes and types, examples may include one or more features, devices, or aspects described herein, individually or in any combination. For example, features described herein may be implemented in a bitstream or signal including information generated as described herein. This information may allow a decoder to decode the bitstream, encoder, bitstream, and / or decoder according to any of the described embodiments. 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 by 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, mobile phone, tablet computer, or other electronic device that performs decoding. The TV, set-top box, mobile phone, tablet computer, or other electronic device may display (e.g., using a monitor, screen, or other type of display) an image obtained (e.g., an image reconstructed from a residual of a video bitstream). The TV, set-top box, mobile phone, tablet computer, or other electronic device may receive a signal including an encoded image and perform decoding.

[0126] When the chroma CTB belongs to a slice encoded or decoded in a single-tree mode or node, systems, methods, and instruments for encoding and / or decoding intra-frame images can be provided. Video codecs can determine the association between the current chroma codec tree block (CTB) and a slice encoded or decoded in a single-tree mode. The video codec can calculate the complete residual luma block co-located with the current chroma CTB. The video codec can then apply the complete residual luma block co-located with the current chroma CTB as input to a chroma adaptive loop filter (ALF) or a cross-component adaptive loop filter (CCALF).

[0127] Based on the determination of the association between the current chroma CTB and the slice encoded and decoded in a separate tree mode, the video codec can derive the co-located luma block. The video codec can obtain intra-frame reference samples associated with the co-located luma block. The video codec can obtain intra-frame prediction modes associated with the co-located luma block. The video codec can predict the co-located luma block based on the intra-frame reference samples and the intra-frame prediction modes. The video codec can compute the residual co-located luma block. The complete residual luma block can be computed as the difference between the reconstructed luma block and the predicted co-located luma block. The video codec can compute the complete residual luma block co-located with the current chroma CTB. The complete residual luma block can be computed using at least the residual co-located luma block. The video codec can apply the complete residual luma block co-located with the current chroma CTB as input to a chroma adaptive loop filter (ALF) or a cross-component adaptive loop filter (CCALF).

[0128] A complete residual luminance block can be computed using each of the complete residual luminance blocks associated with each of the multiple chroma blocks of the current chroma CTB. The video codec can store the residual co-located luminance block within the complete residual luminance block co-located with the current chroma CTB. The video codec can apply the residual chroma block co-located with the current chroma CTB as input to the chroma ALF and CCALF. If cross-component prediction is used for the current chroma CTB, the intra-prediction mode associated with the co-located luminance block can be derived using at least one of a template-based intra-prediction mechanism or a decoder-side intra-prediction mechanism. The intra-prediction mode of the complete residual luminance block can be derived as the most representative intra-prediction mode among multiple intra-prediction modes stored in memory.

[0129] Block-based intra-frame prediction and / or inter-frame prediction, along with transform encoding and decoding (e.g., in conjunction with quantization), can introduce a wide variety of artifacts at low to medium bit rates. For example, artifacts can be reduced by implementing in-loop filters in the video encoding and decoding process, such as deblocking filter (DBF), bilateral filter (BIF), sample adaptive offset (SAO), and / or adaptive loop filter (ALF).

[0130] Deblocking filters (DBFs) can be used to smooth discontinuities that may occur along block boundaries. Sample adaptive offset (SAO) can attenuate artifacts appearing around edges and / or use offsets in signaling transmission within the bitstream to correct for local average intensity variations. Bilateral filters (BIFs) can further denoise and reconstruct artifacts in the image caused by quantization in the transform domain. Adaptive loop filters (ALFs) can be determined as (e.g., optimal) filters on the encoder side according to rate-distortion criteria. ALF filters can be transmitted (e.g., transmitted with the bitstream) and retrieved and used on the decoder side.

[0131] In-loop filters can be implemented. There may be several (e.g., three) types of in-loop filters: deblocking filters (DBF), sample adaptive offset (SAO), and / or adaptive loop filters (ALF). Deblocking filters reduce block discontinuities. Sample adaptive offset reduces artifacts caused by quantization of transform coefficients. Adaptive loop filters and cross-component adaptive loop filters (CCALF) are adaptive filters. Adaptive filters can be used to enhance the reconstructed signal, for example, using Wiener filter coding methods.

[0132] Figure 5 The document describes an example workflow for in-loop filters. For instance, if local deblocking conditions are met, a deblocking filter (DBF) can be used (e.g., first) to filter luminance and / or chromaticity reconstructed samples located along block boundaries. For example, depending on the classification (e.g., based on a band-based or edge-based classifier), a sample adaptive offset (SAO) can be used to locally add an offset. For example, an adaptive loop filter (ALF) and / or a cross-component adaptive loop filter (CCALF) can be run before storing the resulting sample values ​​in a reference image cache.

[0133] Figure 5 The illustration shows an example of a loop filter used in video encoding and decoding.

[0134] ALF is an adaptive filter that can be applied, for example, to reduce the mean square error (MSE) between the original and reconstructed samples using Wiener filter coding methods.

[0135] An ALF filter can be transmitted in the bitstream and decoded on the decoder side. The filter can be derived from parameters transmitted (e.g., previously) or from predefined parameters, for example, before being applied to a reconstructed sample.

[0136] An ALF filter can be, for example, point-symmetric, DC-neutral, and has integer coefficients. An ALF can use, for example, a 7x7 diamond filter for luminance and / or a 5x5 diamond filter for chrominance, such as... Figures 6A-6B The example depicted in the text.

[0137] Figure 6A An example of a luminance ALF 7x7 diamond filter is illustrated. Figure 6B An example of a chroma ALF 5x5 diamond filter is illustrated.

[0138] make To reconstruct the sample, and let This indicates the value after ALF filtering. In example implementations of ALF (e.g., linear implementations), It can be calculated according to formula (1): in Filter coefficients can be indicated. and The value can be calculated, for example, according to formula (2): in It can be marked as the same as the first coefficients The coordinate offsets corresponding to the associated reconstructed samples.

[0139] In example implementations of ALF (e.g., non-linear implementations), equation (1) can be rewritten, for example, according to equation (3): and The value can be calculated, for example, according to formula (4): in It can be with coefficients The associated clipping parameter, which is determined by the clipping index. Confirm. Trimming parameters. For example, it can be derived from formula (5): in It can indicate the sampling depth, and For example, it can be 0, 1, 2 or 3.

[0140] Online filter optimization and / or offline pre-training can be implemented. ALF filter coefficients and / or pruning indices can be determined on the encoder side, for example, by minimizing the MSE between the reconstructed sample and its original value by solving the Wiener-Hopf equation. The coefficients and (if applicable) the corresponding pruning indices can be encoded into an adaptive parameter set (APS) (e.g., if rate-distortion conditions are met). An ALF APS can include luma filters and / or chroma filters. For example, an ALF APS can include one (1) luma filter bank and up to eight (8) chroma filters.

[0141] Video encoding and decoding techniques can use pre-trained (e.g., predefined) luminance filters, which can be hard encoded and decoded on the encoder side and / or the decoder side.

[0142] An ALF for brightness can include local adaptations with classification (e.g., further) and / or features thereof, such as classification based on local gradients. An ALF for brightness can (e.g., therefore) depend on a filter bank, which can include multiple filters. One or more filter banks can be associated with a mapping list (e.g., together with the mapping list). The class of classification (e.g., each class) can be associated with (e.g., a specific) filter in the filter bank. For example, depending on the classification, a geometric filter transformation can be applied. A geometric filter transformation can include, for example, a 90-degree rotation, a diagonal flip, and / or a vertical flip.

[0143] On the encoder and / or decoder sides, multiple (e.g., pre-trained) luma filter banks may be available. The encoder may choose whether to transmit a luma filter bank that may be optimized for the current slice and / or frame, for example, based on a rate-distortion criterion.

[0144] The encoder can (e.g., at the CTU level) determine whether to implement ALF. The encoder can select a luminance filter bank that can be used between a pre-trained filter bank and a filter bank that may have already been transmitted.

[0145] An ALF for chroma (e.g., unlike an ALF for luma) may not implement local classification. An ALF for chroma may (e.g., alternatively) include region adaptation and / or features thereof. In the example, multiple (e.g., up to eight (8)) ALF chroma filters may (e.g., simultaneously) be available on both the encoder and / or decoder sides. (e.g., each) Chroma codec tree block (CTB) may signal the filters it uses.

[0146] ALF and / or variants of ALF can be implemented, such as those described in this article.

[0147] Chromatic ALF can be implemented using a diamond filter size (which can be nine by nine (9x9)).

[0148] ALF can be implemented using a fixed filter for luminance. For example, luminance samples can be based on multiple (e.g., three) different classifiers (e.g., and Filtering is performed using one or more different filter groups (e.g., F0, F1, and F2). Groups F0 and / or F1 may include fixed filters, for example, where the coefficients are tailored to the classifier. and / or Pre-training is performed. The coefficients of the filters in F2 can be signaled. For a given sample, determining which filter from group Fi can be used is based on using the classifier. The species Ci assigned to this sample.

[0149] For example, in addition to the two fixed-brightness filters, a third fixed-brightness filter can be used (e.g., without classification).

[0150] For luminance, an alternative ALF classifier (e.g., an alternative 2x2 ALF classifier) ​​can be used. Signaling transmission flags can be used to indicate whether an alternative classifier is applied to the luminance filter bank of the signaling transmission. Geometric transformations may not be applied to the alternative band-based classifier. For example, if a band-based classifier is applied, the sum of sample values ​​for the luminance blocks (e.g., 2x2 luminance blocks) can be calculated. The class index can be calculated (e.g., then) for example, according to Equation (6): .

[0151] Filtering for luminance ALF signaling transmission can use unblocked samples, residual samples, and / or the output of a fixed filter. The output of the fixed filter, the unblocked samples, and / or the residual samples can be used as (e.g., additional) inputs to the filter for ALF signaling transmission. The value of the (e.g., final) filtered sample can be calculated, for example, according to formula (7): in It can be neighboring samples and the current sample The difference in cutting between them, It can be an intermediate sample generated by the first fixed filter and the current sample. The difference in cutting between them, It can be an intermediate sample generated by a third fixed filter and the current sample. The difference in cutting between them, It can be a co-located intermediate sample generated by the first fixed filter and the current sample. The difference in cutting between them, It can be a co-located intermediate sample generated by the second fixed filter and the current sample. The difference in cutting between them, It can be a co-located intermediate sample generated by a third fixed filter and the current sample. The difference in cutting between them, It can be the neighboring samples before DBF and the current sample. The difference in cutting between them, It can be the co-located samples before DBF and the current samples. The difference in cutting between them, It can be the clipped adjacent residual sample values, and / or It can be a cropped residual sample after filtering by a fixed filter. The fixed filter can be reused (e.g., for residual samples) after SAO for offline fixed filter training for reconstruction.

[0152] Figure 7 An example of the complete filter shape of an ALF using residual samples as (e.g., additional) input is shown in the figure. Figure 7 The illustration shows an example of the filter shape for luminance ALF signaling transmission.

[0153] The Cross-Component Adaptive Loop Filter (CCALF) can refine the chromaticity sample values ​​within the ALF process using luminance samples. The CCALF can be a linear filtering process. Corrections can be generated independently for (e.g., each) chromaticity component, for example, according to Equation (8): in It can identify the reconstructed brightness samples before ALF. It can be the sample location of the chromaticity component. It can be from The derived brightness sample position, Can be marked around The filter supports offset. This can be for chromaticity components. In the filter support area of ​​brightness, and / or It can indicate the position offset The amount The filter coefficients.

[0154] Figure 8 The illustration shows an example of a CCALF-filtered chroma sample and its relative position in the luma plane when the chroma location type is 0 and the chroma format is 4:2:0. CCALF can be implemented using various video codec techniques. For example, a CCALF filter can have a diamond shape, such as... Figure 8 The diagram is shown in the image. In the example, CCALF can choose not to enforce point-symmetric constraints in its coefficients.

[0155] For example, DC neutrality can be preserved if the sum of the CCALF coefficient values ​​is zero. CCALF filters can be optimized on the encoder side and / or transmitted as a bitstream in the ALF Adaptive Parameter Set (APS). The ALF APS can include one or more (e.g., up to four (4)) CCALF filters per chroma component. (E.g., each) CTU can signal the CCALF filters it uses.

[0156] Figure 9The illustration shows an example of a CCALF filter shape, for instance, with a chroma location type of 0 and a chroma format of 4:2:0. In this example, CCALF could be implemented with a larger filter shape (e.g., with 26 coefficients), such as... Figure 9 As illustrated in the diagram. In the example, one or more (e.g., up to 16) CCALF filters can be signaled in the APS.

[0157] Luminance residual taps can be used in the chroma ALF and / or CCALF loop filtering stages. Luminance residuals can be included as input in the chroma ALF and / or CCALF processes. Figure 10 An example of the filter shape for chroma ALF is shown. Figure 10 The diagram also illustrates the luminance residual that can be used as input to the chroma ALF process. Chroma ALF can add one or more (e.g., only one) luminance residual taps. For example, chroma ALF can take the downsampled luminance residual as input.

[0158] Figure 11 An example of the filter shape in CCALF is shown. Figure 11 An example of a luminance residual is also illustrated, which can be used as input to the chroma CCALF process. The space-based taps in chroma ALF and CCALF can remain unchanged. For example, CCALF can add five luminance residual taps (e.g., in a 3x3 cross shape). Extended taps can take luminance residual values ​​at the same and / or adjacent locations as input.

[0159] Various coefficient signaling mechanisms used in video encoding and decoding can be utilized for signaling transmission. The mechanisms described in this paper can be implemented without switching filter shapes.

[0160] Adaptive loop filtering for chroma can provide a gain in compression efficiency compared to non-adaptive loop filtering. The encoding / decoding gain can be (e.g., primarily) obtained in inter-frame images. However, some adaptive loop filtering processes for chroma may not improve compression performance for inter-frame images. Compression performance for intra-frame images can be enhanced using one or more mechanisms described herein compared to chroma ALF and / or CCALF.

[0161] For example, intra-frame compression performance may be limited if intra-frame images are encoded and decoded in a separate tree mode. In separate tree mode, the block partitions of each codec tree unit (CTU) can be represented separately for the luma component on one side and for the two (2) chroma components on the other. The block-based representation of the image in the compression domain may not be aligned between luma and chroma in intra-frame images, but it may be (e.g., perfectly) aligned in inter-frame images. Luma residual data in intra-frame images may be uncorrelated with the signal to be compressed in the chroma components.

[0162] Misalignment between luma and chroma blocks can degrade the performance of chroma ALF and CCALF. Misalignment can cause luma residuals present in the luma component to become uncorrelated with the chroma block to be encoded or decoded.

[0163] In the example, the luminance residual block can be recalculated to spatially align with the chroma block being processed during the chroma ALF and / or CCALF processes. The dynamically recalculated luminance residual can be used as input for the chroma ALF and / or CCALF loop filtering steps.

[0164] Block structures can be implemented in video encoding and decoding. For example, during video compression, images can be divided into codec tree units (CTUs). For example, the size of a CTU can be 64x64, 128x128, or 256x256 pixels.

[0165] Figure 12 An example of a codec tree unit and a codec tree structure is illustrated to represent a compressed image (e.g., an encoded image). A CTU (e.g., each CTU) can be represented by a codec tree in a compression domain. A quadtree partition of a CTU can have many associated leaf nodes, where (e.g., each) a leaf node can be called a codec unit (CU). Figure 12 An example is shown in the image.

[0166] Figure 13 The illustration shows an example of a codec tree unit divided into codec units, prediction units, and transform units. Each CU can be given intra-frame and / or inter-frame prediction parameters (e.g., prediction information). A CU can be partitioned (e.g., spatially partitioned) into one or more prediction units (PUs). Each PU can be assigned prediction information. Intra-frame or inter-frame codec modes can be assigned at the CU level. Figure 13 An example is shown in the image.

[0167] Figure 14 The illustration shows an example of partitioning a codec unit into prediction units. For example, partitioning a codec unit into prediction units(s) can be implemented based on the partition type that may be transmitted in the bitstream as signaling. Figure 14 As illustrated in the example, intra-frame codec units can use (e.g., only) 2N×2N and N×N partition types. Square PUs (e.g., only square PUs) can be used within an intra-frame codec unit.

[0168] Inter-frame coding / decoding units can use square and / or rectangular partition types. For example, an inter-frame coding / decoding unit can use... Figure 14 The examples in the text show (for example, all) partition types.

[0169] Encoding / decoding units can (e.g., also) be recursively divided into transform units, for example, according to a "transform tree". A transform tree can be a quadtree partition of encoding / decoding units. A transform unit can be a leaf node of the transform tree. A transform unit can encapsulate a square transform block associated with (e.g., each) image component of a considered square spatial region. A transform block can be a square block of samples in a single component to which the same transform is applied.

[0170] The codec tree unit representation in the compression domain allows for a more flexible representation of image data. Compared to CU, PU, ​​and / or TU arrangements, the flexible representation of the codec tree offers the advantage of improved compression efficiency.

[0171] Figure 15 The illustration shows an example of a Quadtree Plus Binary Tree (QTBT) CTU representation. QTBT codec tools can provide increased flexibility. A QTBT representation can include a codec tree, where codec units can be segmented in a quadtree and / or binary tree manner. Figure 15 An example of a QTBT codec tree representation of a codec tree unit is shown.

[0172] For example, the segmentation of the codec unit can be determined on the encoder side based on (e.g., using) a rate-distortion optimization procedure. This procedure may include determining the QTBT representation of the CTU with minimum rate-distortion cost.

[0173] In QTBT representation, the CU can be square or rectangular in shape. The size of the codec unit can be (e.g., always) a power of two (2) (such as between four (4) and 128).

[0174] CTU representation can have one or more (e.g., all) of the following characteristics: a variety of rectangular shapes for the codec unit; the QTBT decomposition of the CTU can be multiple (e.g., two) stages; the luma and chroma block partitioning structure can be separated and / or determined independently in intra-frame slices; the CU can be unpartitioned into prediction units or transform units; additional CU partitioning modes can be implemented.

[0175] The QTBT decomposition of the CTU can be performed in one or more (e.g., two) stages. For example, the CTU can be partitioned (e.g., first) as a quadtree, and (e.g., each) quadtree leaf node can be further partitioned as a binary tree, such as... Figure 15 As shown in the example. Figure 15 As shown, solid lines can represent quadtree decomposition stages, and dashed lines can represent binary tree decomposition spatially embedded in the leaf nodes of quadtrees.

[0176] The luminance and chrominance block partitioning structure can be separated and / or determined independently within intra-frame slices.

[0177] A CU may not be partitioned into prediction units or transform units. (For example, each) codec unit may (for example, systematically) consist of a single prediction unit (for example, the previous 2Nx2N prediction unit partitioning type) and / or a single transform unit (for example, not partitioned into a transform tree).

[0178] In one or more types of video codecs, for (e.g., most) CU codec modes, (e.g., most) codec units, the CU may not be partitioned into PUs or TUs. (e.g., each) codec unit may consist of a single prediction unit (e.g., a 2Nx2N prediction unit partitioning type) and / or a single transform unit (e.g., not partitioned into a transform tree). Exceptions may exist. For example, one or more of the following PU or TU partitions may apply to codec units in one or more (e.g., four (4)) codec modes. (e.g., a CU with a width or height greater than 64) may be tiled into TUs of a size equal to the maximum supported transform size. For example, the maximum transform size may be equal to 64. For example, depending on the type of intra-framing sub-partition (ISP) mode used and / or the shape of the CU, an intra-framing CU encoded in ISP mode may be tiled into two (2) or four (4) transform units. An inter-framing CU encoded in sub-block transform (SBT) may be tiled into two (2) transform units, where one of the resulting TUs may have residual data equal to zero. Inter-frame CUs encoded and decoded in Triangle Prediction Combining (TPM) mode can consist of two (2) triangle prediction units, each of which can be assigned its own motion data.

[0179] Figure 16 Examples of horizontal and vertical ternary tree codec unit (CU) partitioning patterns are illustrated. Additional CU partitioning patterns, which can be referred to as horizontal or vertical ternary tree partitioning patterns, can also be implemented. This CU partitioning pattern may include dividing the codec unit (CU) into three (3) sub-codec units (sub-CUs), each sub-CU having a size equal to that of the parent CU. and The corresponding size (e.g., in the direction of the spatial division under consideration). Figure 16 The diagram illustrates examples of horizontal (e.g., HOR_TRIPLE) and vertical (e.g., VER_TRIPLE) tritree codec unit segmentation patterns.

[0180] Figure 17 The diagram illustrates an example of a set (e.g., complete) CU segmentation modes that exist in a codec based on a video codec scheme.

[0181] For example, as described herein, intra-frame images encoded and / or decoded in a single-tree mode may offer poor performance. In single-tree mode, block partitions of (e.g., each) codec tree unit (CTU) can be represented separately for the luma component on one side and for the two (2) chroma components on the other. The block-based representation of the image in the compression domain may be misaligned between luma and chroma in intra-frame images, while it may be (e.g., perfectly) aligned in inter-frame images. Luma residual data in intra-frame images may be uncorrelated with the signal to be compressed in the chroma components, which may not improve the performance of chroma ALF and CCALF in intra-frame slices or images.

[0182] For example, if the current slice, image, or CTU is encoded or decoded in dual-tree mode, the luminance residual signal can be dynamically calculated and used as input for the chroma ALF and / or CCALF processes. Figure 18 The illustration shows an example of using dynamically calculated luminance residual signals as input for the chroma ALF and CCALF processes to perform video encoding and decoding.

[0183] like Figure 18 As shown, the input to the process can be, for example, a chroma codec tree block (chroma CTB). The chroma ALF and CCALF encoding / decoding stages of a video encoder or video decoder can be applied to the chroma CTB.

[0184] At point 11, it can be determined whether the chroma CTB under consideration belongs to a slice encoded and decoded in a single-tree mode. At point 12, for example, if the single-tree mode is off, the first type (e.g., the default) chroma ALF and CCALF procedures can be applied (e.g., without using dynamically recalculated luma residual blocks as input).

[0185] like Figure 18 As shown, for example, if the individual tree mode is enabled, the following may occur: Figure 18 As shown in sections 13-20, a new residual luminance block co-located with the current chromaticity CTB can be dynamically recalculated; and, as... Figure 18As shown at point 21, the dynamically recalculated residual luminance block can be used as input to the chromatic ALF and CCALF processes (e.g., instead of the original or otherwise calculated residual luminance signal used as input to the process).

[0186] At point 13, the CU can be initialized by setting it as the first CU in the current chroma CTB. At points 14-20, an iterative loop can be performed on each (e.g., every) chroma CU included in the current chroma CTB. The co-occurring luma block region of the current chroma CU can be derived for each (e.g., every) chroma CU in the current chroma CTB. For example, depending on the chroma format used in the current image (e.g., 4:2:0, 4:2:2, 4:4:4), the derivation of the co-occurring luma block region can take into account the possible subsampling ratios between the luma and chroma components.

[0187] At position 15, an intra-frame reference sample associated with the derived luma block can be obtained. The intra-frame reference sample may include a set of known neighboring samples located above, to the left, to the upper right, and to the lower left of the luma block considered in the luma component.

[0188] At position 16, the intra-prediction mode of the luma block co-located with the current chromaticity CU can be obtained. The derivation of the luma intra-prediction mode can be implemented using a variety of methods, such as those described in this paper.

[0189] At point 17, for example, based on reference samples and / or the derived intra-frame prediction mode, the current luma block can be predicted (e.g., co-located with the current chroma CU).

[0190] At position 18, a residual luminance block co-located with the current chroma CU can be calculated. For example, the residual luminance block can be calculated as the difference between the reconstructed luminance block and the predicted luminance block. This may result in a residual luminance block co-located with the current chroma CU.

[0191] At position 19, the calculated luminance residual block can be stored in a larger or full luminance residual block. The larger or full residual block can be the desired luminance residual block co-located with the current chromaticity CTB.

[0192] At position 20, the CU can iterate to the next chroma CU in the current chroma CTB. For example, if the iteration loop is completed for the chroma CUs (e.g., all chroma CUs), a larger or complete luminance residual block co-located with the current chroma CTB can be obtained.

[0193] At point 21, the dynamically recalculated luminance residual signal can be used (e.g., based on...). Figure 18(e.g., 13-20 from the luminance CTU encoding / decoding or decoding) is used as input for the chroma ALF and CCALF stages to perform the chroma ALF and CCALF processes. The dynamically recalculated luminance residual signal used during the chroma ALF and CCALF processes may be more relevant to the chroma signal being processed.

[0194] Various mechanisms can be implemented to derive the luma intra-prediction mode. For example, the derivation of the intra-prediction mode associated with a luma block co-located with the chroma CU may depend on the prediction mode associated with the chroma CU. For example, the derivation of the intra-prediction mode associated with a luma block co-located with the chroma CU can be performed according to one or more of the following.

[0195] For example, if the chroma CU is encoded and decoded in chroma DBV mode, for example, the assigned block vector is predicted by motion compensation prediction based on the reconstructed block region in the current chroma image, then the co-located luma block can be rescaled according to the chroma format of the chroma BV, and the IBC prediction mode can be derived using the rescaled chroma BV.

[0196] For example, if a spatial prediction mode is used to predict the chroma CU, the spatial prediction mode can be assigned to a luma block that coexists with the chroma CU. The same spatial intra-frame prediction mode as the chroma CU can be assigned to a luma block that coexists with the chroma CU.

[0197] For example, if the prediction mode of the chroma CU under consideration is cross-component prediction, then the intra-prediction mode (IPM) of the luma block co-located with the chroma CU can be derived as the intra-prediction mode of the luma CU located at the center of the luma block under consideration.

[0198] For example, if cross-component prediction is used in the current chroma CU, the IPM of the luma block can be (e.g., alternatively) derived using the decoder-side intra-mode derivation (DIMD) mechanism.

[0199] For example, if cross-component prediction is used in the current chroma CU, the IPM of the luma block can be (e.g., alternatively) derived according to a template-based intra-mode derivation (TIMD) mechanism.

[0200] For example, if cross-component prediction is used in the current chroma CU, the IPM of the luma block can be (e.g., alternatively) derived according to the TIMD mechanism. The intra-modes of the luma CUs intersecting the luma block region under consideration (e.g., all intra-modes) can be considered as candidate IPMs and compete for them.

[0201] For example, if cross-component prediction is used in the current chroma CU, the IPM of a luma block can be derived as the representative (e.g., most representative) IPM among the IPMs stored in the video codec's memory (e.g., within the luma region corresponding to the luma block under consideration). The IPMs used during the encoding and decoding of a luma block can be stored in memory, for example, on a block-by-block basis (e.g., one IPM per (e.g., 4x4) block). The IPM that is most prevalent in the (e.g., 4x4) blocks covered by the luma block under consideration can be selected as the IPM of that luma block.

[0202] For example, if the IBC or intra-TMP mode is derived for the luma block under consideration, the BV for the current luma block can be taken as the BV stored at the center of the luma block under consideration. The block vectors used during IBC and intra-TMP prediction can be stored in the buffer on an (e.g., 4x4) block basis.

[0203] For example, if an IBC or intra-frame TMP mode is derived for the luma block under consideration, the BV for the current luma block can be taken as the BV represented (e.g., at most) in the BV buffer portion corresponding to the (e.g., 4x4) block covered by the luma block under consideration.

[0204] BV can be derived for the luma block under consideration. The derived BV can be refined, for example, through a template matching refinement mechanism, which may be similar to the template matching refinement of IBC block vectors.

[0205] For example, the derivation of an intra-prediction mode associated with a luma block co-located with the chroma CU can be independent of the prediction mode associated with the chroma CU. For example, the derivation of an intra-prediction mode associated with a luma block co-located with the chroma CU can be performed according to one or more of the following.

[0206] In the example, the IPM of the luma block can be derived based on the DIMD mechanism of various video codec technologies.

[0207] The IPM of a luma block can be derived based on the TIMD mechanism of various video encoding and decoding technologies.

[0208] The IPM of a luma block can be derived based on the TIMD mechanism of various video codecs, where the intra-frame modes of the luma CUs intersecting with the luma block region under consideration (e.g., all intra-frame modes) can be considered as candidate IPMs and compete for the same position.

[0209] The IPM of a luma block (e.g., alternatively) can be derived as the representative (e.g., most representative) IPM among the IPMs in the luma region corresponding to the luma block under consideration, stored in the video codec memory. The IPMs used during the encoding and decoding of a luma block can be stored in memory on a block-by-block basis (e.g., 4x4), such as one IPM per (e.g., 4x4) block. The IPM that is most prevalent in the (e.g., 4x4) blocks covered by the luma block under consideration can be selected as the IPM of that luma block.

[0210] For example, if the IBC or intra-frame TMP prediction mode is derived for the current luma block, the associated derived block vector can be refined through a template matching refinement mechanism.

[0211] In the example, the chroma ALF and CCALF loop filtering stages (e.g., as described herein) can be modified (e.g., further).

[0212] Some chromaticity residuals can (e.g., additionally) be used as input for the chromaticity ALF and / or CCALF processes, for example, in addition to inserting the use of luminance residual information into the chromaticity ALF and / or CCALF processes.

[0213] In the example, some Cb chromaticity residual taps can be used for the chromaticity ALF and / or CCALF of the Cr component for loop filtering of the Cr chromaticity component.

[0214] In the example, conversely, some Cr chromaticity residual taps can be used for the chromaticity ALF and / or CCALF of the Cb components for loop filtering of the Cb components.

[0215] In the example, during the chroma ALF and CCALF processes, both Cb and Cr residual taps can be used for the Cb and Cr components. This is likely because (e.g., all) Cb and Cr block residual data can be decoded before the loop filtering stage occurs (e.g., in both dual-tree and non-dual-tree modes). For (e.g., all) chroma blocks, the two (2) chroma residuals in the corresponding chroma transform can be sequentially encoded and decoded into the bitstream in the same transform unit.

[0216] In the example, if joint Cb and / or Cr residual encoding / decoding is used in the corresponding chroma block, then (e.g., also) chroma residual taps can be used. For example, if joint Cb and / or Cr residual encoding / decoding is used in the corresponding chroma block, then opposite residual information from the Cb and Cr components, respectively, can be input into the chroma ALF and CCALF processes.

[0217] Although the features and elements have been described above in specific combinations, those skilled in the art will appreciate that each feature or element can be used alone or in any combination with other features and elements. Furthermore, the methods described herein can 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, read-only memory (ROM), random access memory (RAM), registers, cache memory, semiconductor storage devices, magnetic media such as internal hard disks and removable disks, magneto-optical media, and optical media such as CD-ROMs and digital versatile discs (DVDs). A processor associated with the software can be used to implement a radio frequency transceiver for use in a WTRU, UE, terminal, base station, RNC, or any host computer.

Claims

1. A video encoding / decoding device, comprising: The processor is configured to at least: Determine the association between the current chroma codec tree block (CTB) and the slice encoded and decoded in a separate tree mode; Calculate the complete residual luminance block co-located with the current chromaticity CTB; as well as The complete residual luminance block co-located with the current chromaticity CTB is applied as input to the chromaticity adaptive loop filter (ALF) or the cross-component adaptive loop filter (CCALF).

2. The video encoding / decoding device according to claim 1, wherein, The processor is configured to at least: Based on the determination that the current chroma CTB is associated with a slice encoded and decoded in a separate tree mode, the co-located luma block is derived; Obtain intra-frame reference samples associated with the co-located luma block; Obtain the intra-prediction mode associated with the co-located luma block; Based on intra-frame reference samples and intra-frame prediction modes, predict co-located lumen blocks; Calculate the residual co-located luminance block, where the complete residual luminance block is calculated as the difference between the reconstructed luminance block and the predicted co-located luminance block; Calculate the complete residual luminance block co-located with the current chromaticity CTB, wherein at least the co-located residual luminance block is used to calculate the complete residual luminance block; and The complete residual luminance block co-located with the current chromaticity CTB is applied as input to the chromaticity adaptive loop filter (ALF) or the cross-component adaptive loop filter (CCALF).

3. The video encoding / decoding device according to claim 2, wherein, The complete residual luminance block is calculated using each of the complete residual luminance blocks associated with each of the multiple chroma blocks of the current chroma CTB.

4. The video encoding / decoding device according to claim 2, wherein, The processor is configured as follows: Store the residual co-located luminance block in the complete residual luminance block co-located with the current chromaticity CTB.

5. The video encoding / decoding device according to claim 1, wherein, The processor is further configured as follows: The residual chromaticity block co-located with the current chromaticity CTB is applied as input to the chromaticity ALF and CCALF.

6. The video encoding / decoding apparatus of claim 2, wherein if cross-component prediction is used for the current chroma CTB, the intra-prediction mode associated with the co-located luma block is derived by at least one of a template-based intra-mode derivation mechanism or a decoder-side intra-mode derivation mechanism.

7. The video encoding / decoding device according to claim 6, wherein, The intra-prediction mode of the complete residual luma block is derived as the most representative intra-prediction mode among the multiple intra-prediction modes stored in memory.

8. A video encoding / decoding method, comprising: Determine the association between the current chroma codec tree block (CTB) and the slice encoded and decoded in a separate tree mode; Calculate the complete residual luminance block co-located with the current chromaticity CTB; as well as The complete residual luminance block co-located with the current chromaticity CTB is applied as input to the chromaticity adaptive loop filter (ALF) or the cross-component adaptive loop filter (CCALF).

9. The video encoding / decoding method according to claim 8, further comprising: Based on the determination that the current chroma CTB is associated with a slice encoded and decoded in a separate tree mode, the co-located luma block is derived; Obtain intra-frame reference samples associated with the co-located luma block; Obtain the intra-prediction mode associated with the co-located luma block; Based on intra-frame reference samples and intra-frame prediction modes, predict co-located lumen blocks; Calculate the residual co-located luminance block, where the complete residual luminance block is calculated as the difference between the reconstructed luminance block and the predicted co-located luminance block; Calculate the complete residual luminance block co-located with the current chromaticity CTB, wherein at least the co-located residual luminance block is used to calculate the complete residual luminance block; and The complete residual luminance block co-located with the current chromaticity CTB is applied as input to the chromaticity adaptive loop filter (ALF) or the cross-component adaptive loop filter (CCALF).

10. The video encoding / decoding method according to claim 9, wherein, The complete residual luminance block is calculated using each of the residual co-located luminance blocks associated with each of the multiple chroma blocks of the current chroma CTB.

11. The video encoding / decoding method according to claim 9, further comprising: Store the residual co-located luminance block in the complete residual luminance block co-located with the current chromaticity CTB.

12. The video encoding / decoding method according to claim 8, further comprising: The residual chromaticity block co-located with the current chromaticity CTB is applied as input to the chromaticity ALF and CCALF.

13. The video encoding / decoding method according to claim 9, wherein if cross-component prediction is used for the current chroma CTB, the intra-prediction mode associated with the co-located luma block is derived by at least one of a template-based intra-mode derivation mechanism or a decoder-side intra-mode derivation mechanism.

14. The video encoding / decoding method according to claim 13, wherein, The intra-prediction mode of the complete residual luma block is derived as the most representative intra-prediction mode among the multiple intra-prediction modes stored in memory.

15. A computer program product stored on a non-transitory computer-readable medium and comprising program code instructions for implementing the steps of the method according to any one of claims 8 to 14 when executed by a processor.

16. A computer program comprising program code instructions for implementing the steps of the method according to any one of claims 8 to 14 when executed by a processor.

17. Video data comprising information representing a codec chroma block generated by the method according to any one of claims 8 to 14.

Images