Chroma Direct Mode

Abstract

A video decoder may be configured to identify a chroma block in the received video data. The video decoder may determine from the received video data that DM intra prediction is applied to the chroma block. The video decoder may retrieve data associated with a luma block corresponding to the identified chroma block. The data associated with the luma block may indicate that DIMD, TIMD, IntraTMP, and / or SGMP are associated with the luma block. On a condition that the received data indicates that DM intra prediction is applied to a chroma block and the data associated with the corresponding luma block indicates that DIMD, and / or TIMD, IntraTMP, and / or SGMP should be applied to the luma block, the video decoder may determine that DIMD, and / or TIMD, IntraTMP, and / or SGMP may also be applied to the corresponding chroma block.

Description

[Technical field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of European Patent Application No. 22305489.1, filed April 08, 2022, and European Patent Application No. 22307025.1, filed December 23, 2022, the contents of which are incorporated by reference in their entireties. [Background technology]

[0002] Video coding systems may be used to compress digital video signals, for example to reduce the storage and / or transmission bandwidth required for such signals. Summary of the Invention

[0003] Systems, methods, and means are disclosed for decoding chroma blocks of video data using a mode associated with a corresponding luma block, provided that Direct Mode (DM) is applied to those chroma blocks. If a chroma block may be in DM mode and the corresponding luma block may have Decoder side Intra Mode Derivation (DIMD), Template-based Intra Mode Derivation (TIMD), Intra Template Matching Prediction (IntraTMP), and / or Spatial Geometric Prediction Mode (SGPM) applied to that luma block, then the chroma block may also have DIMD, TIMD, IntraTMP, and / or SGPM applied to that chroma block.

[0004] The video encoder may be configured to determine that the chroma block may be encrypted and decoded in the same intra-prediction mode as the corresponding luma block. The video encoder may determine that the luma block and the corresponding chroma block may be processed using DIMD, TIMD, IntraTMP, and / or SGPM. The video encoder may generate encoded video data including an indication to process the chroma block using DM. The data may include a flag indicating to process the chroma block using DM. The video data may further include data indicating that the corresponding luma block may be processed using DIMD, TIMD, IntraTMP, and / or SGPM. The video data may also include data indicating that a Low-Frequency Non-Separable Transform (LFNST) index and / or a Multiple Transform Selection (MTS) index is applied for the luma block. The encoder may send the video data to a video decoder.

[0005] The video decoder may be configured to receive video data and determine or identify a chroma block. The video decoder may further determine from the received video data that a DM mode may be applied to the chroma block. For example, the video decoder may identify a flag indicating that DM may be applied to the chroma block.

[0006] The video decoder may retrieve data from the video data for a luma block that corresponds to the identified chroma block. The data associated with the luma block may indicate an intra-prediction mode for the luma block. For example, the data associated with the luma block may indicate that DIMD, TIMD, IntraTMP, and / or SGPM are associated with the luma block and should be applied.

[0007] If the received data indicates that DM is applied to a chroma block, and if the data associated with the corresponding luma block indicates that DIMD, TIMD, IntraTMP, and / or SGPM should be applied to the luma block, the video decoder may determine that DIMD, TIMD, IntraTMP, and / or SGPM may also be applied to the corresponding chroma block. The video decoder may perform DIMD, TIMD, IntraTMP, and / or SGPM on the chroma block as specified in the data associated with the corresponding luma block. If the received data further indicates that an LFNST index and / or an MTS index are applied to the luma block, the video decoder may apply the selected LFNST and / or MTS to the corresponding chroma block.

[0008] The systems, methods, and means may involve a decoder. In some embodiments, the systems, methods, and means described herein may involve an encoder. In some embodiments, the systems, methods, and means described herein may involve a signal (e.g., from an encoder and / or received by a decoder). A computer-readable medium may include instructions for causing one or more processors to perform the methods described herein. A computer program product may include instructions that, when executed by one or more processors, may cause the one or more processors to perform the methods described herein. [Brief description of the drawings]

[0009] [Figure 1A] FIG. 1 is a system diagram illustrating an example communication system in which one or more disclosed embodiments may be implemented. [Figure 1B] 1B is a system diagram illustrating an example wireless transmit / receive unit (WTRU) that may be used within the communications system illustrated in FIG. 1A, according to one embodiment. [Figure 1C]1A is a system diagram illustrating an example radio access network (RAN) and an example core network (CN) that may be used in the communication system illustrated in FIG. 1A, according to one embodiment. [Figure 1D] FIG. 1B is a system diagram illustrating a further example RAN and a further example CN that may be used within the communication system illustrated in FIG. 1A, according to one embodiment. [Diagram 2] FIG. 2 illustrates an example block-based video encoder. [Diagram 3] FIG. 2 illustrates an example video decoder. [Figure 4] FIG. 1 illustrates an example system in which various aspects and embodiments may be implemented. [Diagram 5] A figure showing examples of intra prediction modes in VVC and ECM. [Figure 6] FIG. 13 is a diagram showing an example of derivation of a Most Probable Modes (MPM) list. [Figure 7A] A diagram showing an example of signaling of a selected intra-prediction mode. [Figure 7B] A diagram showing an example of signaling of a selected intra-prediction mode. [Figure 8] A diagram showing an example of signaling of a selected intra-prediction mode. [Figure 9] FIG. 13 is a diagram illustrating an example of template matching prediction. [Figure 10] FIG. 13 shows an example of SGPM template analysis for candidate list construction. [Figure 11] FIG. 1 illustrates an example process for decoding chroma data using direct mode (DM) intra prediction and DIMD / TIMD. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] A more detailed understanding may be had from the following description, given by way of example in conjunction with the accompanying drawings, in which:

[0011] 1A is a diagram illustrating an example communication system 100 in which one or more disclosed embodiments may be implemented. The communication system 100 may be a multiple access system that provides content, such as voice, data, video, messaging, broadcasts, etc., to multiple wireless users. The communication system 100 may enable multiple wireless users to access such content through sharing of system resources, including wireless bandwidth. For example, the communications system 100 may use one or more channel access methods, such as code division multiple access (CDMA), time division multiple access (TDMA), frequency division multiple access (FDMA), orthogonal FDMA (OFDMA), single-carrier FDMA (SC-FDMA), zero-tail unique-word DFT-Spread OFDM (ZT UW DTS-s OFDM), unique word OFDM (UW-OFDM), resource block filtered OFDM, filter bank multicarrier (FBMC), and the like.

[0012] 1A, communications 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, although it will be understood that the disclosed embodiments contemplate any number of WTRUs, base stations, networks, and / or network elements. Each of WTRUs 102a, 102b, 102c, 102d may be any type of device configured to operate and / or communicate in a wireless environment. By way of example, the WTRUs 102a, 102b, 102c, 102d, any of which may be referred to as a "station" and / or "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, wireless paging, mobile phones, personal digital assistants (PDAs), smartphones, laptops, netbooks, personal computers, wireless sensors, hotspots or Mi-Fi devices, Internet of Things (loT) devices, watches or other wearable head-mounted displays (HMDs), vehicles, drones, medical devices and applications (e.g., for remote surgery), industrial devices and applications (e.g., robots and / or other wireless devices operating in an industrial and / or automated processing chain context), consumer electronics devices, devices operating in commercial and / or industrial wireless networks, and the like. Any of the UEs 102a, 102b, 102c, and 102d may be referred to interchangeably as a WTRU.

[0013] The communication system 100 may also include a base station 114a and / or a base station 114b. Each of the base stations 114a, 114b may be any type of device configured to wirelessly interface with at least one of the WTRUs 102a, 102b, 102c, 102d to facilitate access to one or more communication networks, such as the CN 106 / 115, the Internet 110, and / or other networks 112. By way of example, the base stations 114a, 114b may be a base station transceiver station (BTS), a Node B, an eNode B, a Home Node B, a Home eNode B, a gNB, an NR Node B, a site controller, an access point (AP), a wireless router, etc. Although the base stations 114a, 114b are each illustrated as a single element, it will be understood that the base stations 114a, 114b may include any number of interconnected base stations and / or network elements.

[0014] The base station 114a may be part of the RAN 104 / 113, which may also include other base stations and / or network elements (not shown), such as a base station controller (BSC), a radio network controller (RNC), a relay node, etc. The base station 114a and / or the base station 114b may be configured to transmit and / or receive wireless signals on one or more carrier frequencies, which may be referred to as cells (not shown). These frequencies may be licensed spectrum, unlicensed spectrum, or a combination of licensed and unlicensed spectrum. A cell may provide wireless service coverage for a particular 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 the base station 114a may be divided into three sectors. Thus, in one embodiment, the base station 114a may include three transceivers, i.e., one transceiver for each sector of the cell. In one embodiment, the base station 114a may employ multiple-input multiple output (MIMO) technology and may utilize multiple transceivers for each sector of the cell, for example, using beamforming to transmit and / or receive signals in a desired spatial direction.

[0015] The base stations 114a, 114b may communicate with one or more of the WTRUs 102a, 102b, 102c, 102d via an air interface 116, which may be any suitable wireless communication link (e.g., radio frequency (RF), microwave, centimeter wave, micrometer wave, infrared (IR), ultraviolet (UV), visible light, etc.). The air interface 116 may be established using any suitable radio access technology (RAT).

[0016] More specifically, as noted above, the communications system 100 may be a multiple access system, but may use one or more channel access schemes, such as CDMA, TDMA, FDMA, OFDMA, SC-FDMA, etc. For example, the base stations 114a and the WTRUs 102a, 102b, 102c in the RAN 104 / 113 may implement a radio technology, such as Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access (UTRA), which may establish the air interface 115 / 116 / 117 using wideband CDMA (WCDMA). WCDMA may include communications protocols such as High-Speed ​​Packet Access (HSPA) and / or Evolved HSPA (HSPA+). HSPA may include High-Speed ​​Downlink (DL) Packet Access (HSDPA) and / or High-Speed ​​Uplink Packet Access (HSUPA).

[0017] In one embodiment, the base station 114a and the WTRUs 102a, 102b, 102c may implement a radio technology such as Evolved UMTS Terrestrial Radio Access (E-UTRA), which may establish the air interface 116 using Long Term Evolution (LTE) and / or LTE-Advanced (LTE-A) and / or LTE-Advanced Pro (LTE-A Pro).

[0018] In one embodiment, the base station 114a and the WTRUs 102a, 102b, 102c may implement a radio technology such as NR radio access, which may establish the air interface 116 using New Radio (NR).

[0019] In one embodiment, the base station 114a and the WTRUs 102a, 102b, 102c may implement multiple radio access technologies. For example, the base station 114a and the WTRUs 102a, 102b, 102c may implement LTE radio access and NR radio access together, e.g., using dual connectivity (DC) principles. Thus, the air interface utilized by the WTRUs 102a, 102b, 102c may be characterized by multiple types of radio access technologies and / or transmissions sent to and from multiple types of base stations (e.g., eNBs and gNBs).

[0020] In other embodiments, the base station 114a and the WTRUs 102a, 102b, 102c may implement a wireless technology such as IEEE 802.11 (i.e., Wireless Fidelity, WiFi), IEEE 802.16 (i.e., Worldwide Interoperability for Microwave Access, WiMAX), CDMA2000, CDMA2000 1X, CDMA2000 EV-DO, Interim Standard 2000 (IS-2000), Interim Standard 95 (IS-95), Interim Standard 856 (IS-856), Global System for Mobile communications (GSM), Enhanced Data rates for GSM Evolution (EDGE), GSM EDGE (GERAN), or the like.

[0021] 1A may be, for example, a wireless router, a Home NodeB, a Home eNodeB, or an access point, and may utilize any suitable RAT to facilitate wireless connectivity in a localized area, such as an office, a home, a vehicle, a campus, an industrial facility, an air corridor (e.g., for use by drones), a road, etc. In one embodiment, the base station 114b and the WTRUs 102c, 102d may implement a radio technology, such as IEEE 802.11, to establish a wireless local area network (WLAN). In one embodiment, the base station 114b and the WTRUs 102c, 102d may implement a radio technology, such as IEEE 802.15, to establish a wireless personal area network (WPAN). In yet another embodiment, the base station 114b and the WTRUs 102c, 102d may establish a picocell or a femtocell using a cellular-based RAT (e.g., WCDMA, CDMA2000, GSM, LTE, LTE-A, LTE-A Pro, NR, etc.). As shown in FIG. 1A, the base station 114b may have a direct connection to the Internet 110. Thus, the base station 114b may not need to access the Internet 110 via the CN 106 / 115.

[0022] The RAN 104 / 113 may communicate with the CN 106 / 115, which may be any type of network configured to provide voice, data, application, and / or voice over internet protocol (VoIP) services to one or more of the WTRUs 102a, 102b, 102c, 102d. The data may have various quality of service (QoS) requirements, such as, for example, different throughput requirements, latency requirements, error tolerance requirements, reliability requirements, data throughput requirements, mobility requirements, etc. The CN 106 / 115 may provide call control, billing services, mobile location-based services, prepaid calling, Internet connectivity, video distribution, etc., and / or perform high level security functions such as user authentication. Although not shown in FIG. 1A, it will be appreciated that the RAN 104 / 113 and / or the CN 106 / 115 may communicate directly or indirectly with other RANs that use the same RAT as the RAN 104 / 113 or a different RAT. For example, in addition to being connected to the RAN 104 / 113, which may utilize NR radio technology, the CN 106 / 115 may also communicate with another RAN (not shown) using GSM, UMTS, CDMA2000, WiMAX, E-UTRA, or WiFi radio technology.

[0023] The CN 106 / 115 may also act as a gateway for the WTRUs 102a, 102b, 102c, 102d to access the PSTN 108, the Internet 110, and / or other networks 112. The PSTN 108 may include a circuit-switched telephone network providing plain old telephone service (POTS). The Internet 110 may include a global system of interconnected computer networks and devices that use common communication protocols, such as transmission control protocol (TCP), user datagram protocol (UDP), and / or internet protocol (IP) of the TCP / IP Internet protocol suite. The networks 112 may include wired and / or wireless communication networks owned and / or operated by other service providers. For example, the networks 112 may include another CN connected to one or more RANs, which may use the same RAT as the RANs 104 / 113 or a different RAT.

[0024] Some or all of the WTRUs 102a, 102b, 102c, 102d in the communications system 100 may include multi-mode capabilities (e.g., the WTRUs 102a, 102b, 102c, 102d may include multiple transceivers for communicating with different wireless networks over different wireless links). For example, the WTRU 102c shown in FIG. 1A may be configured to communicate with a base station 114a, which may employ a cellular-based wireless technology, and a base station 114b, which may employ an IEEE 802 wireless technology.

[0025] Figure 1B is a system diagram illustrating an example WTRU 102. As shown in Figure 1B, the WTRU 102 may include, among other things, a processor 118, a transceiver 120, a transmit / receive element 122, a speaker / microphone 124, a keypad 126, a display / touchpad 128, non-removable memory 130, removable memory 132, a power source 134, a global positioning system (GPS) chipset 136, and / or other peripherals 138. It will be understood that the WTRU 102 may include any sub-combination of the foregoing elements while remaining consistent with an embodiment.

[0026] The processor 118 may 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. The processor 118 may perform signal coding, data processing, power control, input / output processing, and / or any other functionality that enables the WTRU 102 to operate in a wireless environment. The processor 118 may be coupled to the transceiver 120, which may be coupled to the transmit / receive element 122. Although FIG. 1B illustrates the processor 118 and the transceiver 120 as separate components, it will be understood that the processor 118 and the transceiver 120 may be integrated together in an electronic package or chip.

[0027] The transmit / receive element 122 may be configured to transmit or receive signals to or from a base station (e.g., base station 114a) over the air interface 116. For example, in one embodiment, the transmit / receive element 122 may be an antenna configured to transmit and / or receive RF signals. In one embodiment, the transmit / receive element 122 may be an emitter / detector configured to transmit and / or receive IR, UV, or visible light signals, for example. In yet another embodiment, the transmit / receive element 122 may be configured to transmit and / or receive both RF and light signals. It will be appreciated that the transmit / receive element 122 may be configured to transmit and / or receive any combination of wireless signals.

[0028] 1B as a single element, the WTRU 102 may include any number of transmit / receive elements 122. More specifically, the WTRU 102 may employ MIMO technology. Thus, in one embodiment, the WTRU 102 may include two or more transmit / receive elements 122 (e.g., multiple antennas) for transmitting and receiving wireless signals over the air interface 116.

[0029] The transceiver 120 may be configured to modulate signals transmitted by the transmit / receive element 122 and demodulate signals received by the transmit / receive element 122. As mentioned above, the WTRU 102 may have multi-mode capabilities. Thus, the transceiver 120 may include multiple transceivers to enable the WTRU 102 to communicate via multiple RATs, such as, for example, NR and IEEE 802.11.

[0030] The processor 118 of the WTRU 102 may be coupled to and may receive user-entered data from a speaker / microphone 124, a keypad 126, and / or a display / touchpad 128 (e.g., a liquid crystal display (LCD) display unit or an organic light-emitting diode (OLED) display unit). The processor 118 may also output user data to the speaker / microphone 124, the keypad 126, and / or the display / touchpad 128. In addition, the processor 118 may access information from and store data in any type of suitable memory, such as non-removable memory 130 and / or removable memory 132. The non-removable memory 130 may include random-access memory (RAM), read-only memory (ROM), a hard disk, or any other type of memory storage device. The removable memory 132 may include a subscriber identity module (SIM) card, a memory stick, a secure digital (SD) memory card, etc. In other embodiments, the processor 118 may access information from and store data in memory that is not physically located on the WTRU 102, such as on a server or home computer (not shown).

[0031] The processor 118 may receive power from the power source 134 and may be configured to distribute and / or control the power to other components within the WTRU 102. The power source 134 may be any suitable device for providing power to the WTRU 102. For example, the power source 134 may include one or more dry batteries (e.g., nickel-cadmium (NiCd), nickel-zinc (NiZn), nickel metal hydride (NiMH), lithium-ion (Li-ion), etc.), solar cells, fuel cells, etc.

[0032] The processor 118 may also be coupled to a GPS chipset 136, which may be configured to provide location information (e.g., longitude and latitude) regarding the current location of the WTRU 102. In addition to, or in lieu of, information from the GPS chipset 136, the WTRU 102 may receive location information from a base station (e.g., base stations 114a, 114b) over 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 appreciated that the WTRU 102 may obtain location information by way of any suitable position determination method while remaining consistent with an embodiment.

[0033] The processor 118 may further be coupled to other peripherals 138, which may include one or more software and / or hardware modules that provide additional features, functionality, and / or wired or wireless connectivity. For example, the peripherals 138 may include an accelerometer, an electronic compass, a satellite transceiver, a digital camera (for photos and / or videos), a universal serial bus (USB) port, a vibration device, a television transceiver, a hands-free headset, a Bluetooth® module, a frequency modulated (FM) radio unit, a digital music player, a media player, a video game player module, an Internet browser, a virtual reality and / or augmented reality (VR / AR) device, an activity tracker, and the like. The peripherals 138 may include one or more sensors, which may be one or more of a gyroscope, an accelerometer, a Hall effect sensor, a magnetometer, an orientation sensor, a proximity sensor, a temperature sensor, a time sensor, a geolocation sensor, an altimeter, a light sensor, a touch sensor, a magnetometer, a barometer, a gesture sensor, a biometric sensor, and / or a humidity sensor.

[0034] The WTRU 102 may include a full-duplex radio where transmission and reception of some or all of the signals associated with a particular subframe (e.g., for both the UL (e.g., for transmission) and the downlink (e.g., for reception) may be parallel and / or simultaneous. The full-duplex radio may include an interference management unit to reduce and or substantially eliminate self-interference via either hardware (e.g., a choke) or signal processing via a processor (e.g., via a separate processor (not shown) or via the processor 118). In one embodiment, the WRTU 102 may include a half-duplex radio for transmission and reception of either some or all of the signals (e.g., associated with a particular subframe for either the UL (e.g., for transmission) or the downlink (e.g., for reception)).

[0035] 1C is a system diagram illustrating the RAN 104 and the CN 106, according to one embodiment. As mentioned above, the RAN 104 may employ E-UTRA radio technology to communicate with the WTRUs 102a, 102b, 102c over the air interface 116. The RAN 104 may also be in communication with the CN 106.

[0036] The RAN 104 may include eNodeBs 160a, 160b, 160c, although it will be understood that the RAN 104 may include any number of eNodeBs while remaining consistent with an embodiment. The eNodeBs 160a, 160b, 160c may each include one or more transceivers for communicating with the WTRUs 102a, 102b, 102c over the air interface 116. In an embodiment, the eNodeBs 160a, 160b, 160c may implement MIMO technology. Thus, the eNodeB 160a may, for example, use multiple antennas to transmit wireless signals to and / or receive wireless signals from the WTRU 102a.

[0037] Each of the eNodeBs 160a, 160b, 160c may be associated with a particular cell (not shown) and may be configured to handle radio resource management decisions, handover decisions, scheduling of users in the UL and / or DL, etc. As shown in FIG 1C, the eNodeBs 160a, 160b, 160c may communicate with one another via an X2 interface.

[0038] 1C may include a mobility management entity (MME) 162, a serving gateway (SGW) 164, and a packet data network (PDN) gateway (or PGW) 166. Although each of the foregoing elements is illustrated 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.

[0039] The MME 162 may be connected to each of the eNodeBs 162a, 162b, 162c in the RAN 104 via an S1 interface and may function as a control node. For example, the MME 162 may be responsible for authenticating users of the WTRUs 102a, 102b, 102c, activating / deactivating bearers, selecting a particular serving gateway during initial attachment of the WTRUs 102a, 102b, 102c, etc. The MME 162 may provide a control plane function for switching between the RAN 104 and other RANs (not shown) that employ other radio technologies, such as GSM and / or WCDMA.

[0040] The SGW 164 may be connected to each of the eNodeBs 160a, 160b, 160c in the RAN 104 via an S1 interface. The SGW 164 may generally route and forward user data packets to and from the WTRUs 102a, 102b, 102c. The SGW 164 may perform other functions, such as anchoring the user plane during inter-eNodeB handover, triggering paging when DL data is available to the WTRUs 102a, 102b, 102c, and managing and storing the context of the WTRUs 102a, 102b, 102c.

[0041] The SGW 164 may be connected to a PGW 166, which may provide the WTRUs 102a, 102b, 102c with access to packet-switched networks, such as the Internet 110, to facilitate communications between the WTRUs 102a, 102b, 102c and IP-enabled devices.

[0042] The CN 106 may facilitate communications with other networks. For example, the CN 106 may provide the WTRUs 102a, 102b, 102c with access to circuit-switched networks, such as the PSTN 108, to facilitate communications between the WTRUs 102a, 102b, 102c and traditional land-line communications devices. For example, the CN 106 may include or be in communication with an IP gateway (e.g., an IP Multimedia Subsystem (IMS) server) that serves as an interface between the CN 106 and the PSTN 108. In addition, the CN 106 may provide the WTRUs 102a, 102b, 102c with access to other networks 112, which may include other wired and / or wireless networks owned and / or operated by other service providers.

[0043] Although the WTRU is depicted in FIGS. 1A-1D as a wireless terminal, in certain representative embodiments, it is contemplated that such a terminal may use a wired communications interface (e.g., temporarily or permanently) with the communications network.

[0044] In an exemplary embodiment, the other network 112 may be a WLAN.

[0045] A WLAN in infrastructure Basic Service Set (BSS) mode may have an Access Point (AP) of the BSS and one or more stations (STAs) associated with the AP. The AP may have access or interface to a Distribution System (DS) or another type of wired / wireless network that carries traffic into and / or out of the BSS. Traffic originating from outside the BSS to the STA may arrive through the AP and be delivered to the STA. Traffic originating from the STA to a destination outside the BSS may be sent to the AP to be delivered to the respective destination. Traffic between STAs within the BSS may be sent, for example, through the AP, where the source STA may send traffic to the AP, which may deliver the traffic to the destination STA. Traffic between STAs within the BSS may be considered and / or referred to as peer-to-peer traffic. Peer-to-peer traffic may be sent between (e.g., directly between) the source STA and the destination STA using a direct link setup (DLS). In certain representative embodiments, the DLS may use 802.11e DLS or 802.11z tunneled DLS (TDLS). A WLAN using an Independent BSS (IBSS) mode may not have an AP, and STAs (e.g., all of the STAs) within or using the IBSS may communicate directly with each other. The IBSS mode of communication may be referred to herein as an "ad-hoc" communication mode.

[0046] When using an 802.11ac infrastructure mode of operation or a similar mode of operation, an AP may transmit a beacon on a fixed channel, such as a primary channel. The primary channel may be a fixed width (e.g., a 20 MHz wide bandwidth) or a width that is dynamically set via signaling. The primary channel may be the operating channel of the BSS, but may be used by STAs to establish a connection with the AP. In certain representative embodiments, for example, in an 802.11 system, Carrier Sense Multiple Access with Collision Avoidance (CSMA / CA) may be implemented. With CSMA / CA, STAs (e.g., all STAs), including the AP, may sense the primary channel. If the primary channel is sensed / detected and / or determined to be busy by a particular STA, the particular STA may back off. One STA (e.g., only one station) may transmit at any given time in a given BSS.

[0047] A High Throughput (HT) STA may use a 40 MHz wide channel for communication, which may be formed, for example, through a combination of a primary 20 MHz channel and adjacent or non-adjacent 20 MHz channels.

[0048] A Very High Throughput (VHT) STA may support 20 MHz, 40 MHz, 80 MHz, and / or 160 MHz wide channels. A 40 MHz and / or 80 MHz channel may be formed by combining multiple contiguous 20 MHz channels. A 160 MHz channel may be formed by combining eight contiguous 20 MHz channels or by combining two non-contiguous 80 MHz channels, which may be referred to as an 80+80 configuration. For the 80+80 configuration, after channel encoding, the data may pass through a segment parser that may split the data into two streams. Inverse Fast Fourier Transform (IFFT) processing and time domain processing may be performed separately on each stream. The streams may be mapped to two 80 MHz channels and the data may be transmitted by the transmitting STA. At the receiver of the receiving STA, the operations described above for the 80+80 configuration may be reversed and the combined data may be transmitted to the Medium Access Control (MAC).

[0049] Sub-1 GHz operating modes are supported by 802.11af and 802.11ah. Channel operating bandwidths and carriers are reduced in 802.11af and 802.11ah compared to those used in 802.11n and 802.11ac. 802.11af supports 5 MHz, 10 MHz, and 20 MHz bandwidths in TV White Space (TVWS) spectrum, and 802.11ah supports 1 MHz, 2 MHz, 4 MHz, 8 MHz, and 16 MHz bandwidths using non-TVWS spectrum. According to a representative embodiment, 802.11ah may support meter-type control / machine-type communication, such as MTC devices in macro coverage areas. MTC devices may have limited capabilities, including certain capabilities, for example, support for (e.g., support only for) certain and / or limited bandwidths. MTC devices may include batteries with above-threshold battery life (e.g., to maintain very long battery life).

[0050] WLAN systems that may support multiple channels and channel bandwidths, such as 802.11n, 802.11ac, 802.11af, and 802.11ah, include a channel that may be selected as a primary channel. The primary channel may have a bandwidth equal to the maximum common operating bandwidth supported by all STAs in the BSS. The bandwidth of the primary channel may be configured and / or limited by the STAs among all STAs operating in the BSS that support the smallest bandwidth operating mode. In an 802.11ah embodiment, the primary channel may be 1 MHz wide for STAs (e.g., MTC-type devices) that support (e.g., only) 1 MHz mode, even if the AP and other STAs in the BSS support 2 MHz, 4 MHz, 8 MHz, 16 MHz, and / or other channel bandwidth operating modes. Carrier sensing and / or Network Allocation Vector (NAV) configuration may depend on the status of the primary channel. For example, if the primary channel is active due to a STA (that only supports the 1 MHz mode of operation) transmitting to the AP, the entire available frequency band may be considered active even though most of the frequency band may remain dormant and available.

[0051] In the United States, the available frequency bands that can be used by 802.11ah are 902MHz to 928MHz. In South Korea, the available frequency bands are 917.5MHz to 923.5MHz. In Japan, the available frequency bands are 916.5MHz to 927.5MHz. The total bandwidth available for 802.11ah is 6MHz to 26MHz depending on the country code.

[0052] 1D is a system diagram illustrating the RAN 113 and the CN 115, according to one embodiment. As mentioned above, the RAN 113 may employ NR radio technology and communicate with the WTRUs 102a, 102b, 102c over the air interface 116. The RAN 113 may also communicate with the CN 115.

[0053] The RAN 113 may include gNBs 180a, 180b, 180c, although it will be understood that the RAN 113 may include any number of gNBs while remaining consistent with an embodiment. The gNBs 180a, 180b, 180c may each include one or more transceivers for communicating with the WTRUs 102a, 102b, 102c over the air interface 116. In an embodiment, the gNBs 180a, 180b, 180c may implement MIMO technology. For example, the gNBs 180a, 108b may utilize beamforming to transmit signals to and / or receive signals from the gNBs 180a, 180b, 180c. Thus, the gNB 180a may transmit and / or receive wireless signals to and from the WTRU 102a, for example, using multiple antennas. In one embodiment, the gNBs 180a, 180b, 180c may implement carrier aggregation technology. For example, the gNB 180a may transmit multiple component carriers to the WTRU 102a (not shown). A subset of these component carriers may be on an unlicensed spectrum, while the remaining component carriers may be on a licensed spectrum. In one embodiment, the gNBs 180a, 180b, 180c may implement Coordinated Multi-Point (CoMP) technology. For example, the WTRU 102a may receive coordinated transmissions from the gNBs 180a and 180b (and / or gNB 180c).

[0054] The WTRUs 102a, 102b, 102c may communicate with the gNBs 180a, 180b, 180c using transmissions associated with scalable numerology. For example, the OFDM symbol spacing and / or OFDM subcarrier spacing may vary for different transmissions, different cells, and / or different portions of the wireless transmission spectrum. The WTRUs 102a, 102b, 102c may communicate with the gNBs 180a, 180b, 180c using subframes or transmission time intervals (TTIs) of different or scalable lengths (e.g., including different numbers of OFDM symbols and / or lasting different lengths of absolute time).

[0055] The gNBs 180a, 180b, 180c may be configured to communicate with the WTRUs 102a, 102b, 102c in a standalone configuration and / or a non-standalone configuration. In a standalone configuration, the WTRUs 102a, 102b, 102c may communicate with the gNBs 180a, 180b, 180c without accessing another RAN (e.g., eNodeBs 160a, 160b, 160c, etc.). In a standalone configuration, the WTRUs 102a, 102b, 102c may utilize one or more of the gNBs 180a, 180b, 180c as mobility anchor points. In a standalone configuration, the WTRUs 102a, 102b, 102c may communicate with the gNBs 180a, 180b, 180c using signals in unlicensed bands. In a non-standalone configuration, the WTRUs 102a, 102b, 102c may communicate with and connect to a gNB 180a, 180b, 180c while also communicating with and connecting to another RAN, such as an eNodeB 160a, 160b, 160c. For example, the WTRUs 102a, 102b, 102c may implement DC principles to communicate with one or more gNBs 180a, 180b, 180c and one or more eNodeBs 160a, 160b, 160c substantially simultaneously. In a non-standalone configuration, the eNodeBs 160a, 160b, 160c may act as mobility anchors for the WTRUs 102a, 102b, 102c, and the gNBs 180a, 180b, 180c may provide additional coverage and / or throughput for serving the WTRUs 102a, 102b, 102c.

[0056] Each of the gNBs 180a, 180b, 180c may be associated with a particular cell (not shown) and may be configured to handle radio resource management decisions, handover decisions, scheduling of users in the UL and / or DL, support for network slicing, dual connectivity, interworking between NR and E-UTRA, routing of user plane data to User Plane Functions (UPFs) 184a, 184b, routing of control plane information to Access and Mobility Management Functions (AMFs) 182a, 182b, etc. As shown in FIG. 1D, the gNBs 180a, 180b, 180c may communicate with each other via an Xn interface.

[0057] 1D may include at least one AMF 182a, 182b, at least one UPF 184a, 184b, at least one Session Management Function (SMF) 183a, 183b, and possibly a Data Network (DN) 185a, 185b. Although each of the foregoing elements is illustrated 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.

[0058] The AMF 182a, 182b may be connected to one or more of the gNBs 180a, 180b, 180c in the RAN 113 via an N2 interface and may function as a control node. For example, the AMF 182a, 182b may be responsible for authenticating users of the WTRUs 102a, 102b, 102c, supporting network slicing (e.g., handling different PDU sessions with different requirements), selecting a particular SMF 183a, 183b, managing registration areas, terminating NAS signaling, mobility management, etc. Network slicing may be used by the AMF 182a, 182b to customize the CN support of the WTRUs 102a, 102b, 102c based on the type of service utilizing the WTRUs 102a, 102b, 102c. For example, different network slices may be established for different use cases such as services relying on ultra-reliable low latency (URLLC) access, services relying on enhanced massive mobile broadband (eMBB) access, services for machine type communication (MTC) access, etc. The AMF 162 may provide a control plane function for switching between the RAN 113 and other RANs (not shown) that employ other radio technologies such as LTE, LTE-A, LTE-A Pro, and / or non-3GPP access technologies such as WiFi.

[0059] The SMFs 183a, 183b may be connected to the AMFs 182a, 182b in the CN 115 via an N11 interface. The SMFs 183a, 183b may also be connected to the UPFs 184a, 184b in the CN 115 via an N4 interface. The SMFs 183a, 183b may select and control the UPFs 184a, 184b and configure the routing of traffic through the UPFs 184a, 184b. The SMFs 183a, 183b may perform other functions such as managing and allocating UE IP addresses, managing PDU sessions, controlling policy enforcement and QoS, providing downlink data notification, etc. The PDU session type may be IP-based, non-IP-based, Ethernet-based, etc.

[0060] The UPFs 184a, 184b may be connected to one or more of the gNBs 180a, 180b, 180c in the RAN 113 via an N3 interface, which may provide the WTRUs 102a, 102b, 102c with access to packet-switched networks, such as the Internet 110, to facilitate communications between the WTRUs 102a, 102b, 102c and IP-enabled devices. The UPFs 184, 184b may perform other functions, such as routing and forwarding packets, enforcing user plane policies, supporting multi-homed PDU sessions, handling user plane QoS, buffering downlink packets, providing mobility anchoring, etc.

[0061] The CN 115 may facilitate communication with other networks. For example, the CN 115 may include or communicate with an IP gateway (e.g., an IP Multimedia Subsystem (IMS) server) that serves as an interface between the CN 115 and the PSTN 108. In addition, the CN 115 may provide the WTRUs 102a, 102b, 102c with access to other networks 112, which may include other wired and / or wireless networks owned and / or operated by other service providers. In one embodiment, the WTRUs 102a, 102b, 102c may be connected to local data networks (DNs) 185a, 185b through the UPFs 184a, 184b via an N3 interface to the UPFs 184a, 184b and an N6 interface between the UPFs 184a, 184b and the DNs 185a, 185b.

[0062] 1A-1D and the corresponding description thereof, one or more or all of the functions described herein with respect to one or more of the WTRUs 102a-d, base stations 114a-b, eNodeBs 160a-c, MME 162, SGW 164, PGW 166, gNBs 180a-c, AMFs 182a-b, UPFs 184a-b, SMFs 183a-b, DNs 185a-b, and / or any other devices described herein may be performed by one or more emulation devices (not shown). The emulation devices may be one or more devices configured to emulate one or more or all of the functions described herein. For example, the emulation devices may be used to test other devices and / or to simulate network and / or WTRU functions.

[0063] The emulation device may be designed to perform one or more tests of other devices in a lab environment and / or an operator network environment. For example, one or more emulation devices may perform one or more or all functions while fully or partially implemented and / or deployed as part of a wired and / or wireless communication network to test other devices in the communication network. One or more emulation devices may perform one or more or all functions while temporarily implemented / deployed as part of a wired and / or wireless communication network. The emulation device may be directly coupled to another device for testing purposes and / or may perform the tests using terrestrial wireless communication.

[0064] The one or more emulation devices may perform one or more functions, inclusive, while not being implemented / deployed as part of a wired and / or wireless communication network. For example, the emulation devices may be utilized in test scenarios in a test lab and / or in an undeployed (e.g., test) wired and / or wireless communication network to perform testing of one or more components. The one or more emulation devices may be test equipment. Direct RF coupling and / or wireless communication via RF circuitry (which may include, for example, one or more antennas) may be used by the emulation devices to transmit and / or receive data.

[0065] This application describes various aspects, including tools, features, examples, models, techniques, and the like. Many of these aspects are described with specificity and often described in a potentially limiting manner to at least illustrate their individual characteristics. However, this is for purposes of clarity of description and does not limit the applicability or scope of the aspects. In fact, all of the different aspects may be combined and interchanged to provide further aspects. Moreover, these aspects may be combined and interchanged with aspects described in prior applications.

[0066] Aspects described and contemplated in this application may be implemented in many different forms. Figures 5-11 described herein may provide some examples, but other examples are contemplated. Discussion of Figures 5-11 is not intended to limit the scope of implementations. At least one of the above aspects generally relates to video encoding and decoding, and at least one other aspect generally relates to transmitting a generated or encoded bitstream. These and other aspects may be implemented as a method, an apparatus, a computer-readable storage medium having stored thereon instructions for encoding or decoding video data according to any of the described methods, and / or a computer-readable storage medium having stored thereon a bitstream generated according to any of the described methods.

[0067] In this application, the terms "reconstructed" and "decoded" may be used interchangeably, the terms "pixel" and "sample" may be used interchangeably, and the terms "image", "picture", and "frame" may be used interchangeably.

[0068] Various methods are described herein, each of which includes one or more steps or acts for achieving the described method. Unless a specific order of steps or acts is required for proper operation of the method, the order and / or use of specific steps and / or acts may be modified or combined. Additionally, terms such as "first", "second", etc. may be used in various embodiments to modify elements, components, steps, operations, etc., such as, for example, "first decode" and "second decode". The use of such terms does not imply any ordering to the modified operations, unless specifically required. Thus, in this embodiment, the first decode need not be performed before the second decode, but may occur, for example, before, during, or during a period of overlap with the second decode.

[0069] Various methods and other aspects described herein may be used to modify modules, such as the decoding modules, of the video encoder 200 and decoder 300, as shown in Figures 2 and 3. Moreover, the subject matter disclosed herein may apply to any type, format, or version of video coding, whether described in a standard or recommendation, whether existing or developed in the future, and to extensions of any such standards and recommendations, for example. Unless otherwise indicated or technically impossible, aspects described herein may be used individually or in combination.

[0070] In the examples describing this application, various numerical values ​​are used to illustrate the embodiments, and the aspects described are not limited to these particular values.

[0071] 2 illustrates an example video encoder. Although variations of the example encoder 200 are contemplated, the encoder 200 is described herein for purposes of clarity without describing all anticipated variations.

[0072] Before being encoded, a video sequence may undergo pre-encoding processing (201), such as applying a color transformation to the input color picture (e.g., converting from RGB 4:4:4 to YCbCr 4:2:0) or performing a remapping of the input picture components to obtain a signal distribution that is more resilient to compression (e.g., using histogram equalization of one of the color components). Metadata may be associated with the pre-processing and attached to the bitstream.

[0073] As described herein, in the encoder 200, a picture is coded by the encoder elements. The picture to be coded is divided (202) and processed, for example, in units of coding units (CUs). Each unit is coded, for example, using either intra mode or inter mode. When a unit is coded in intra mode, it performs intra prediction (260). In inter mode, motion estimation (275) and motion compensation (270) are performed. The encoder determines (205) whether intra mode or inter mode should be used to code the unit, and indicates the decision, for example, by a prediction mode flag. A prediction residual is calculated, for example, by subtracting (210) the prediction block from the original image block.

[0074] The prediction residual is then transformed (225) and quantized (230). The quantized transform coefficients, as well as the motion vectors and other syntax elements, are entropy coded (245) to output a bitstream. The encoder may skip the transform and apply quantization directly to the untransformed residual signal. The encoder may bypass the transform and quantization, i.e., the residual is directly coded without applying a transform or quantization process.

[0075] The encoder decodes the coded block to provide a reference for further prediction. It dequantizes (240) and inverse transforms (250) the quantized transform coefficients and decodes the prediction residual. It combines (255) the decoded prediction residual with the predicted block to reconstruct an image block. An in-loop filter (265) is applied to the reconstructed picture to perform, for example, deblocking / Sample Adaptive Offset (SAO) filtering to reduce coding artifacts. It stores the filtered image in a reference picture buffer (280).

[0076] 3 illustrates an example video decoder. In the example decoder 300, a bitstream is decoded by a decoder element as described herein. The video decoder 300 generally performs a decoding path that is the inverse of the encoding path described in FIG. 2. Additionally, the encoder 200 generally performs video decoding as part of the video data encoding.

[0077] The decoder's input includes a video bitstream, which may be generated by the video encoder 200. The bitstream is first entropy decoded (330) to obtain transform coefficients, motion vectors, and other coded information. Picture partition information indicates how the picture is partitioned. The decoder may then partition (335) the picture according to the decoded picture partition information. The decoder dequantizes (340) and inverse transforms (350) the transform coefficients and decodes the prediction residual. The decoded prediction residual is combined (355) with a predicted block to reconstruct an image block. The predicted block may be obtained (370) from intra prediction (360) or from motion-compensated prediction (i.e., inter prediction) (375). An in-loop filter (365) is applied to the reconstructed image. The filtered image is stored in a reference picture buffer (380).

[0078] The decoded picture may further undergo post-decoding processing (385), such as an inverse color conversion (e.g., from YCbCr 4:2:0 to RGB 4:4:4) or inverse remapping that performs the inverse of the remapping process performed in the pre-encoding processing (201). The post-decoding processing may use metadata derived in the pre-encoding processing and signaled in the bitstream. In an embodiment, the decoded image (e.g., after application of an in-loop filter (365) and / or after post-decoding processing (385), if post-decoding processing is used) may be sent to a display device for rendering to a user.

[0079] FIG. 4 illustrates an example of a system in which various aspects and embodiments described herein may be implemented. System 400 may be embodied as a device including various components described herein and configured to perform one or more of the aspects described herein. Examples of such devices include various electronic devices, such as, but not limited to, personal computers, laptop computers, smartphones, tablet computers, digital multimedia set-top boxes, digital television receivers, personal video recording systems, connected appliances, and servers. The elements of system 400, singly or in combination, may be embodied in a single integrated circuit (IC), multiple ICs, and / or separate components. For example, in at least one embodiment, the processing and encoder / decoder elements of system 400 are distributed across multiple ICs and / or separate components. In various embodiments, system 400 is communicatively coupled to one or more other systems or other electronic devices, for example, via a communication bus or through dedicated input and / or output ports. In various embodiments, system 400 is configured to perform one or more of the aspects described herein.

[0080] The system 400 includes at least one processor 410 configured to execute instructions loaded therein, for example to implement various aspects described herein. The processor 410 may include embedded memory, input / output interfaces, and various other circuits known in the art. The system 400 includes at least one memory 420 (e.g., volatile and / or non-volatile memory devices). The system 400 includes a storage device 440, which may include non-volatile and / or volatile memory, including, but not limited to, electrically erasable programmable read-only memory (EEPROM), read-only memory (ROM), programmable read-only memory (PROM), random access memory (RAM), dynamic random access memory (DRAM), static random access memory (SRAM), flash, magnetic disk drives, and / or optical disk drives. The storage device 440 may include, by way of non-limiting example, an internal storage device, an attached storage device (including removable and non-removable storage devices), and / or a network-accessible storage device.

[0081] The system 400 includes an encoder / decoder module 430, which may include its own processor and memory, configured to process data to provide, for example, encoded or decoded video. The encoder / decoder module 430 represents a module that may be included within a device to perform encoding and / or decoding functions. As is known, a device may include one or both of an encoding module and a decoding module. Additionally, the encoder / decoder module 430 may be implemented as a separate element of the system 400 or may be incorporated within the processor 410 as a combination of hardware and software known to those skilled in the art.

[0082] Program code to be loaded into the processor 410 or the encoder / decoder 430 to perform various aspects described herein may be stored in the storage device 440 and then loaded into the memory 420 for execution by the processor 410. According to various embodiments, one or more of the processor 410, the memory 420, the storage device 440, and the encoder / decoder module 430 may store one or more of a variety of items during performance of the processes described herein. 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, expressions, operations, and operational logic.

[0083] In some embodiments, memory internal to the processor 410 and / or the encoder / decoder module 430 is used to store instructions and provide working memory for processing required during encoding or decoding. However, in other embodiments, memory external to the processing device (e.g., the processing device can be either the processor 410 or the encoder / decoder module 430) is used for one or more of these functions. The external memory may be the memory 420 and / or the storage device 440, e.g., dynamic volatile memory and / or non-volatile flash memory. In some embodiments, an external non-volatile flash memory is used, e.g., to store the television's operating system. In at least one embodiment, a high-speed external dynamic volatile memory, such as a RAM, is used as working memory for video encoding and decoding operations.

[0084] Inputs to the elements of system 400 may be provided through various input devices, as shown in block 445. Such input devices may include, but are not limited to, (i) a radio frequency (RF) section, for example, receiving an RF signal transmitted over the air by a broadcast station, (ii) a component (COMP) input terminal (or set of COMP input terminals), (iii) a universal serial bus (USB) input terminal, and / or (iv) a high definition multimedia interface (HDMI) input terminal. Another example, not shown in FIG. 4, is composite video.

[0085] In various embodiments, the input devices of block 445 have associated respective input processing elements as known in the art. For example, the RF section may be associated with elements suitable for (i) selecting a desired frequency (also referred to as selecting a signal or band-limiting a signal to a frequency band), (ii) down-converting the selected signal, (iii) band-limiting again to a narrow frequency band to select a signal frequency band that may be referred to as a channel in a particular embodiment (e.g.), (iv) demodulating the down-converted band-limited signal, (v) performing error correction, and (vi) demultiplexing to select a desired stream of data packets. The RF section of various embodiments includes one or more elements for performing these functions, such as a frequency selector, a signal selector, a band limiter, a channel selector, a filter, a down-converter, a demodulator, an error corrector, and a demultiplexer. The RF section may include a tuner to perform various of these functions, including, for example, down-converting a received signal to a lower frequency (e.g., an intermediate frequency or a near-baseband frequency) or to baseband. In one set-top box embodiment, the RF section and its associated input processing elements receive RF signals transmitted over a wired (e.g., cable) medium and perform frequency selection by filtering, down-converting, and filtering again to a desired frequency band. Various embodiments rearrange the order of the above-described (and other) elements, remove some of these elements, and / or add other elements to perform similar or different functions. Adding elements can include inserting elements between existing elements, such as, for example, inserting amplifiers and analog-to-digital converters. In various embodiments, the RF section includes an antenna.

[0086] In addition, the USB and / or HDMI terminals may include respective interface processors for connecting the system 400 to other electronic devices via USB and / or HDMI connections. It should be appreciated that various aspects of the input processing, such as Reed-Solomon error correction, may be implemented, for example, in a separate input processing IC or in the processor 410, as desired. Similarly, aspects of the USB or HDMI interface processing may be implemented, for example, in a separate interface IC or in the processor 410, as desired. The demodulated, error corrected, and demultiplexed stream is provided to various processing elements, including, for example, an encoder / decoder 430 operating in combination with the processor 410 and memory and storage elements that process the data stream as desired for presentation on an output device.

[0087] The various elements of system 400 may be provided within an integrated housing in which the various elements may be interconnected and transmit data between them using suitable connection arrangements 425, such as internal buses as are known in the art, including Inter-IC (I2C) buses, wiring, and printed circuit boards.

[0088] System 400 includes a communication interface 450 that enables communication with other devices over a communication channel 460. Communication interface 450 may include, but is not limited to, a transceiver configured to transmit and receive data over communication channel 460. Communication interface 450 may include a modem or a network card, and communication channel 460 may be implemented, for example, but is not limited to, in a wired and / or wireless medium.

[0089] Data is streamed or otherwise provided to system 400 in various embodiments using a wireless network such as a Wi-Fi network, e.g., IEEE 802.11 (IEEE refers to the Institute of Electrical and Electronics Engineers). The Wi-Fi signal in these embodiments is received via communication channel 460 and communication interface 450 adapted for Wi-Fi communication. Communication channel 460 in these embodiments is typically connected to an access point or router that provides access to external networks, including the Internet, to enable streaming applications and other over-the-top communications. Other embodiments provide streamed data to system 400 using a set-top box that delivers data via an HDMI connection in input block 445. Still other embodiments provide streamed data to system 400 using an RF connection in input block 445. As noted above, various embodiments provide data in a non-streaming manner. Additionally, various embodiments use wireless networks other than Wi-Fi, e.g., cellular networks or Bluetooth networks.

[0090] The system 400 may provide output signals to various output devices, including a display 475, speakers 485, and other peripheral devices 495. The display 475 in various embodiments includes, for example, one or more of a touch screen display, an organic light emitting diode (OLED) display, a curved display, and / or a foldable display. The display 475 may be for a television, a tablet, a laptop, a mobile phone, or other device. Furthermore, the display 475 may be integrated with other components (e.g., as in a smart phone) or may be separate (e.g., an external monitor for a laptop). The other peripheral devices 495 in various embodiments include one or more of a stand-alone digital video disc (or digital versatile disc) (DVD for both terms), a disc player, a stereo system, and / or a lighting system. Various embodiments use one or more peripheral devices 495 that provide functionality based on the output of the system 400. For example, a disc player performs the function of playing the output of the system 400.

[0091] In various embodiments, control signals are communicated between system 400 and display 475, speaker 485, or other peripheral devices 495 using signaling such as AV.Link, Consumer Electronics Control (CEC), or other communication protocols that allow control between devices with or without user intervention. Output devices may be communicatively coupled to system 400 via dedicated connections through respective interfaces 470, 480, and 490. Alternatively, output devices may be connected to system 400 via communication interface 450 using communication channel 460. Display 475 and speaker 485 may be integrated into a single unit with other components of system 400 in an electronic device such as, for example, a television. In various embodiments, display interface 470 includes a display driver, such as, for example, a timing controller (TCon) chip.

[0092] Display 475 and speakers 485 may alternatively be separate from one or more of the other components, for example, if the RF portion of input 445 is part of a separate set-top box. In various embodiments in which display 475 and speakers 485 are external components, output signals may be provided via dedicated output connections including, for example, an HDMI port, a USB port, or a COMP output.

[0093] These embodiments may be performed by the processor 410, or by computer software implemented by hardware, or by a combination of hardware and software. As a non-limiting example, these embodiments may be implemented by one or more integrated circuits. The memory 420 may be of any type suitable for the technology environment, and may be implemented using any suitable data storage technology, such as, as non-limiting examples, optical memory devices, magnetic memory devices, semiconductor-based memory devices, fixed memories, and removable memories. The processor 410 may be of any type suitable for the technology environment, and may include, as non-limiting examples, one or more of a microprocessor, a general-purpose computer, a special-purpose computer, and a processor based on a multi-core architecture.

[0094] Various implementations involve decoding. As used herein, "decoding" may encompass all or a portion of the processes performed on a received encoded sequence to generate a final output suitable for, for example, a display. In various embodiments, such processes include one or more of the processes typically performed by a decoder, such as entropy decoding, inverse quantization, inverse transform, and differential decoding. In various embodiments, such processes may also or alternatively include processes performed by the decoder in various implementations described herein, such as applying a prediction process associated with a corresponding luma block to a chroma block, provided that the chroma block can be identified as being in the DM. As a further example, in one embodiment, "decoding" refers to entropy decoding only, in another embodiment, "decoding" refers to differential decoding only, and in another embodiment, "decoding" refers to a combination of entropy decoding and differential decoding. Whether the phrase "decoding process" is intended to refer specifically to a subset of operations or to the broader decoding process as a whole will be clear based on the context of the specific description and will be well understood by those skilled in the art.

[0095] Various implementations involve encoding. Similar to the above discussion regarding "decoding," "encoding" as used herein can encompass, for example, all or part of the processes performed on an input video sequence to produce an encoded bitstream. In various embodiments, such processes include one or more of the processes typically performed by an encoder, such as, for example, performing a convolution, obtaining a latent vector, generating motion flow data, etc. In various embodiments, such processes also or alternatively include processes performed by an encoder in various implementations described herein, such as, for example, determining that a chroma block may have had the same prediction process applied to it as the corresponding luma block and including an indicator in the encoded video data.

[0096] As a further example, in one embodiment, "encoding" refers to only entropy encoding, while in another embodiment, "encoding" refers to only differential encoding, while in another embodiment, "encoding" refers to a combination of differential and entropy encoding. Whether the phrase "encoding process" is intended to refer specifically to a subset of operations or to the broader encoding process as a whole will be clear based on the context of the specific description and will be well understood by one of ordinary skill in the art.

[0097] It should be noted that the syntax elements used herein, e.g., latent vectors, attention values, etc., are descriptive terms and therefore do not preclude the use of other syntax element names.

[0098] Where a figure is presented as a flow diagram, it should be understood that the figure also provides a block diagram of the corresponding apparatus. Similarly, where a figure is presented as a block diagram, it should be understood that the figure also provides a flow diagram of the corresponding method / process.

[0099] The implementations and aspects described herein may be implemented, for example, in a method or process, an apparatus, a software program, a data stream, or a signal. Even if discussed in the context of only a single implementation form (e.g., discussed only as a method), the implementation of the discussed features may also be implemented in other forms (e.g., an apparatus or a program). An apparatus may be implemented, for example, in appropriate hardware, software, and firmware. A method may be implemented, for example, in a processor, which generally refers to a processing device and includes, for example, a computer, a microprocessor, an integrated circuit, or a programmable logic device. Processors also include communication devices, such as, for example, computers, cellular phones, portable / personal digital assistants ("PDAs"), and other devices that facilitate communication of information between end users.

[0100] References to "one example" or "an example" or "one implementation" or "an implementation," as well as other variations thereof, mean that a particular feature, structure, characteristic, etc. described in connection with an embodiment is included in at least one embodiment. Thus, the appearances of the phrases "in one example" or "in an example" or "in one implementation" or "in an implementation" in various places throughout this application, as well as any other variations, are not necessarily all referring to the same embodiment.

[0101] Additionally, the application may refer to "determining" various information. Determining information may include, for example, one or more of estimating information, calculating information, predicting information, or retrieving information from a memory. Obtaining may include receiving, retrieving, constructing, generating, and / or determining.

[0102] Additionally, the application may refer to "accessing" various information. Accessing information may include, for example, one or more of receiving information, retrieving information (e.g., from a memory), storing information, moving information, copying information, calculating information, determining information, predicting information, or estimating information.

[0103] Additionally, the application may refer to "receiving" various information. Receiving, like "accessing," is intended to be a broad term. Receiving information may include, for example, one or more of accessing information or retrieving information (e.g., from a memory). Furthermore, "receiving" generally involves in some manner an operation, 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.

[0104] For example, in the case of "A / B," "A and / or B," and "at least one of A and B," it should be understood that the use of any of the following " / ," "and / or," and "at least one of" is intended to encompass the selection of only the first enumerated alternative (A), or the selection of only the second enumerated alternative (B), or the selection of both alternatives (A and B). As a further example, in the case of "A, B, and / or C" and "at least one of A, B, and C," such language is intended to encompass the selection of only the first enumerated alternative (A), or the selection of only the second enumerated alternative (B), or the selection of only the third enumerated alternative (C), or the selection of only the first and second enumerated alternatives (A and B), or the selection of only the first and third enumerated alternatives (A and C), or the selection of only the second and third enumerated alternatives (B and C), or the selection of all three alternatives (A and B and C). This can be expanded as many times as the items listed, as would be apparent to one of ordinary skill in this and related arts.

[0105] Also, as used herein, the term "signaling" specifically means to indicate something to a corresponding decoder. Encoder signals may include, for example, an indication of motion flow data, an indication of quantized motion flow data, etc. In this way, in one embodiment, the same parameters are used on both the encoder and decoder sides. Thus, for example, the encoder may transmit a particular parameter to the decoder so that the decoder can use the same particular parameter (explicit signaling). Conversely, if the decoder already has the particular parameter as well as other parameters, it may use signaling without transmitting, simply to allow the decoder to know and select the particular parameter (implicit signaling). By avoiding transmitting any actual function, bit savings are realized in various embodiments. It should be understood that signaling may be achieved in various ways. For example, in various embodiments, one or more syntax elements, flags, etc. are used to signal information to a corresponding decoder. Although the above relates to the verb form of the term "signal", the term "signal" may also be used as a noun in this specification.

[0106] As will be apparent to one of ordinary skill in the art, implementations may generate a variety of signals formatted to carry information that may be, for example, stored or transmitted. Information may include, for example, instructions for performing a method or data generated by one of the described implementations. For example, a signal may be formatted to carry a bit stream of the described embodiments. Such a signal may be formatted, for example, as an electromagnetic wave (e.g., using a radio frequency portion of the spectrum) or as a baseband signal. Formatting may include, for example, encoding a data stream and modulating a carrier wave with the encoded data stream. The information that the signal carries may be, for example, analog information or digital information. The signal may be transmitted by a variety of different wired or wireless links, as is well known. The signal may be stored in, accessed from, or received from a processor-readable medium.

[0107] Many examples are described herein. Features of the examples may be provided alone or in any combination across various claim categories and types. Furthermore, examples may include one or more of the features, devices, or aspects described herein, alone or in any combination across various claim categories and types. For example, features described herein may be embodied in a bitstream or signal that includes information generated as described herein. The information may enable 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 generating and / or transmitting and / or receiving and / or decoding a bitstream or signal. For example, features described herein may be implemented as a method, process, apparatus, medium storing instructions, medium storing data, or signal. For example, features described herein may be implemented by a TV, a set-top box, a mobile phone, a tablet, or other electronic device that performs decoding. A TV, set-top box, mobile phone, tablet, or other electronic device may display (e.g., using a monitor, screen, or other type of display) the resulting image (e.g., an image from the residual reconstruction of the video bitstream). A TV, set-top box, mobile phone, tablet, or other electronic device may receive a signal that includes the encoded image and perform decoding.

[0108] Systems, methods, and means are disclosed for encoding and decoding chroma blocks of video data using a mode associated with a corresponding luma block, provided that a direct mode (DM) is applied to the chroma block. If a chroma block may be in DM mode and the corresponding luma block may have decoder-side intra mode derivation (DIMD), template-based intra mode derivation (TIMD), intra template matching prediction (IntraTMP), and / or spatial geometric prediction mode (SGPM), e.g., prediction processes applied to the luma block, then the chroma block may also have DIMD, TIMD, IntraTMP, and / or SGPM, e.g., prediction processes applied to the chroma block.

[0109] The video decoder may be programmed to receive video data and determine or identify a chroma block within the video data. The video decoder may determine from the received video data that a chroma block may have direct mode (DM) intra prediction associated with it. For example, the video decoder may identify a flag within the video data that indicates that DM intra prediction may be applied to the chroma block.

[0110] The video decoder may retrieve data from the received video data for the luma block corresponding to the identified chroma block. The data associated with the luma block may indicate an intra-prediction mode for the luma block. For example, the data may indicate that DIMD, TIMD, IntraTMP, and / or SGPM are associated with and should be applied to the luma block. On a condition that the received data indicates that DM intra prediction is applied to a chroma block and the data associated with the corresponding luma block indicates that DIMD, TIMD, IntraTMP, and / or SGPM, e.g., prediction processes, should be applied to the luma block, the video decoder may determine that DIMD, TIMD, IntraTMP, and / or SGPM, e.g., prediction processes, may be applied to the corresponding chroma block as well. The video decoder may perform intra prediction on the chroma block that matches the identified intra-prediction mode for the luma block and may perform DIMD, TIMD, IntraTMP, and / or SGPM on the chroma block as specified in the data associated with the corresponding luma block. Provided that the received data further indicates an LFNST index or an MTS index for the luma block, the video decoder may apply the selected LFNST and / or MTS to the corresponding chroma block.

[0111] The disclosed system, method, and means may be applied in the context of video coding. The disclosed system, method, and means may be applied to chroma direct mode (DM), where the chroma intra prediction mode may be similar, e.g., the same, as the luma intra prediction mode. The system, method, and means may employ decoder-side intra mode derivation (DIMD), template-based intra mode derivation (TIMD), IntraTMP, and / or SGPM for a chroma block if DIMD, TIMD, IntraTMP, and / or SGPM are applied to the corresponding luma block. If DM is used, a transform index that may be applied to a luma block may be similarly applied to the associated chroma block.

[0112] Intra prediction may be a coding tool, for example, a basic one, employed in composite video coding. An encoder may select an intra prediction mode, for example, the best, in terms of rate distortion, for a given block to be predicted, and may signal an index of the intra prediction mode to a decoder so that the decoder may perform the same prediction for that particular block. Signaling the selected intra prediction mode index may add extra overhead, which may reduce the gain obtained from intra prediction. One way to code the index of the selected intra prediction mode to predict a given block may be to create a set of Most Probable Modes (MPMs). Using a set of MPMs may reduce the signaling overhead if the index of the selected intra prediction mode belongs to that list. This method, which is, for example, a classical method for signaling intra prediction mode indexes, may be referred to as MPM list-based signaling, for example, and may be employed in VVC and HEVC. MPM list-based signaling may also be employed in ECM, in which case two MPM lists may be used instead of one. It is understood that with respect to MPM list-based signaling, the signaling of mode index may be referred to as mode signaling for short.

[0113] In HEVC, VVC, and ECM, MPM list-based signaling may be dedicated, e.g., only for signaling the intra-prediction mode selected to predict the luma block. The signaling of the chroma intra-prediction mode may be different from the signaling of the luma intra-prediction mode. In relation to chroma processing, the signaling overhead may remain relatively small. This is because, for a given pair of chroma blocks, e.g., a co-located Cb block and a Cr block that are gathered, the selected intra-prediction mode may be only one, e.g., only, of planar, DC, horizontal, vertical intra-prediction modes, or the same intra-prediction mode selected to predict the luma block co-located with that particular pair of chroma blocks. It is said that the direct mode (DM) is applied when the mode is the same as the intra-prediction mode selected to predict the luma block co-located with that particular pair of chroma blocks. In VVC and ECM, for a given pair of chroma blocks, the selected intra prediction mode can also be a Cross-Component Linear Model (CCLM) mode.

[0114] In ECM, luma intra prediction may be extended by two decoder-side mode derivation methods: decoder-side intra mode derivation (DIMD) and template-based intra mode derivation (TIMD). If a given pair of chroma blocks, such as a co-located Cb block and Cr block, may be coded using a DM intra prediction mode, and if the luma block co-located with the pair of chroma blocks uses either TIMD or DIMD, the intra prediction mode for the pair of chroma blocks may be the same derived intra mode as specified in the data for the luma block. However, under existing procedures, applying DM to chroma blocks may limit coding performance, since DIMD / TIMD may not be applied to chroma blocks.

[0115] Disclosed herein are systems, methods, and means for performing DIMD / TIMD on a given pair of chroma blocks when DM is selected and the luma block co-located with the pair of chroma blocks is coded with DIMD / TIMD. If DM is selected and the luma block is subjected to multiple transform selection (MTS) and / or low frequency non-separable transform (LFNST), e.g., a transform process, the corresponding chroma block may be subjected to MTS and / or LFNST, e.g., a transform process as well. This allows chroma MTS and may reduce chroma LFNST signaling.

[0116] 67 core intra prediction modes may be available. To capture any edge direction presented in the raw video, the number of directional intra prediction modes in VVC may be extended to 65 from the 33 used in HEVC. Figure 5 shows intra prediction modes that may be used in VVC and ECM. The directional modes added in VVC compared to HEVC may be represented by dotted lines in Figure 5. As shown, the additional modes dense the possible intra prediction mode choices. The dense directional intra prediction modes may be applied to all block sizes and to luma intra prediction and chroma intra prediction. In VVC, some conventional angle-based intra prediction modes may be adaptively replaced with wide-angle intra prediction modes for non-square blocks.

[0117] In the change from HEVC to VVC, the planar and DC modes may remain unchanged except for the following minor modifications: In HEVC, intra-coded blocks, e.g., every single intra-coded block, may have a square shape, and the length of each of its sides may be a power of two. Thus, division may be unnecessary to generate an intra predictor using DC mode. In VVC, blocks may have a rectangular shape, which allows for, e.g., mandates, the use of block-wise division in the general case. To avoid division for DC prediction, only the long side, e.g., the long side, may be used to calculate the average of non-square blocks.

[0118] In ECM, a core structure of 67 intra prediction modes may be inherited from VVC. This core structure may be refined in ECM. The 4-tap interpolation for directional intra prediction modes may become 6-tap interpolation. Position Dependent Intra Prediction Combination (PDPC) may be complemented with gradient-based PDPC.

[0119] Intra prediction mode signaling may be supported by the ECM. Intra prediction mode signaling may be applied to luma. In the ECM, if the intra prediction mode selected to predict the current luma coding block (CB) is not DIMD, matrix-based intra prediction (MIP) mode, or TIMD, e.g., one of the 67 intra prediction modes mentioned in this specification, its index may be signaled using the MPM list of the CB. Following some procedures, Block Difference Pulse Code Modulation (BDPCM), template-based intra prediction (TMP), Intra Block Copy (IBC), and palette may be exclusively enabled for a particular video sequence, e.g., screen content, so these tools may be ignored. In the ECM, the generic MPM list may be decomposed into a list of six primary MPMs and a list of 22 secondary MPMs. FIG. 6 illustrates an example of derivation of a generic MPM list for a current luma CB belonging to an intra slice in an ECM. The generic MPM list may be constructed by sequentially adding candidates for intra prediction mode indexes from the most likely candidate to the least likely candidate to be the selected intra prediction mode for predicting the current luma CB. From left to right, FIG. 6 illustrates sequential addition of intra prediction mode index candidates for which the current luma CB may belong to an intra slice. There may be no redundancy in the generic list of the MPM, i.e., two identical intra prediction mode indices may not be included in the list. FIG. 6 illustrates an example in which each intra prediction mode index candidate may be different from each other. However, in a general example, the slots from index 0 to i-1 in the generic list of the MPM may be previously filled.If the current intra-prediction mode index candidate is already present in the current generic list of the MPM, the candidate may be skipped, and if the next candidate intra-prediction mode is not present in the generic list of the MPM, it may be inserted into the slot with index i. Otherwise, the current intra-prediction mode index may be inserted into the slot with index i, and if the next candidate intra-prediction mode is not present in the generic list of the MPM, it may be inserted into the slot with index i+1.

[0120] 7A and 7B show a signaling example of an intra prediction mode selected to predict a current luma CB in an ECM. In the signaling example shown in FIG. 7A and FIG. 7B, this signaling may be applied to an encoder-side process. This signaling example may also be applied to a decoder-side process. In FIG. 7A and FIG. 7B, an MRL may be used to represent a multiple reference line. If the TIMD flag is equal to 1, the MRL index may belong to {0, 1, 3}. When the MRL index is 0, this may indicate that the MRL is not used to predict the current luma CB. When the MRL index is 1, this may indicate that the second row of decoded reference samples above the current luma CB and the second column of decoded reference samples to the left of the current luma CB may be used for prediction. When the MRL index is 3, this may indicate that the fourth row of decoded reference samples above the current luma CB and the fourth column of decoded reference samples to the left of the current luma CB may be used for prediction. If the TIMD flag is equal to 0, the MRL index may belong to {0, 1, 3, 5, 7, 12}. ISP stands for Intra Sub-Partition. The ISP mode index may belong to {0, 1, 2}. When the ISP mode index is 0, it may indicate that the ISP may not be used for the current luma CB. When the ISP mode index is 1, it may indicate that the current luma CB may be separated horizontally into luma transform blocks (TBs). When the ISP mode index is 2, it may indicate that the current luma CB may be separated vertically into luma TBs. In FIG. 7A and FIG. 7B, the BDPCM, TMP, IBC, and palette tools are omitted because these tools may be exclusively turned on for a video sequence, e.g., a particular video sequence.

[0121] Intra-prediction mode signaling in chrominance may be supported in ECM. FIG. 8 shows an example of signaling of an intra-prediction mode selected to predict a current pair of chrominance CBs, e.g., co-located Cb and Cr CBs, in ECM. In FIG. 8, if the DM flag is equal to 1, the four possibilities for the current intra-prediction mode index may be the indexes of planar mode, horizontal mode, vertical mode, and DC. To avoid redundancy, if the DM is one of the four modes mentioned above, in this set of four modes, the index of the redundant mode may be replaced by the index of the mode in the vertical diagonal. In ECM, a cross-component linear model (CCLM) may collect six different intra-prediction modes, which may be represented as LM, MMLM, MDLM_L, MDLM_T, MMLM_L, and MMLM_T. In VVC, the CCLM may collect three, e.g., only three, intra-prediction modes.

[0122] Decoder-side intra mode derivation (DIMD) may be supported. For a given luma CB to be predicted, DIMD may derive two intra prediction modes from a template of reconstructed neighboring samples surrounding a CB, and these two predictors may be combined with a planar mode predictor using weights derived from gradients in the template. The division in the weight derivation may be performed utilizing the same look-up table (LUT)-based integerization scheme used by CCLM. For example, the division in the orientation calculation, Orient=G y / G x can be calculated by the following LUT-based scheme: x=Floor(Log2(Gx)) normDiff=((Gx<<4)>>x)& 15 x +=(3+(normDiff !=0)? 1:0) Orient = (Gy * (DivSigTable[normDiff]|8)+(1<<(x-1)))>>x During the ceremony, DivSigTable

[16] = {0, 7, 6, 5, 5, 4, 4, 3, 3, 2, 2, 1, 1, 1, 1, 0}. The two derived intra modes may be included in a generic MPM list. Thus, for a given luminance CB to be predicted, a DIMD process may be performed before creating the MPM list. For a given luminance CB, the primary intra mode derived by DIMD may be stored and used for MPM list construction of neighboring luminance CBs.

[0123] IntraTMP in ECM may be supported. Intra template matching prediction may be referred to as intra TMP or TMP, and may be an intra prediction mode, such as a dedicated intra prediction mode that copies a prediction block, such as a best prediction block, from the reconstructed part of the current frame, where the L-shaped template matches the current template. In a predefined search range, the encoder may search for a template similar to the current template, such as the most similar template, in the reconstructed part of the current frame, and may use the corresponding block as a prediction block. The encoder may send information indicating that this mode is used. The same prediction operation may be performed on the decoder side.

[0124] Figure 9 shows an example of an intra template matching search region. A prediction signal can be generated by matching an L-shaped causal neighborhood of a current block with another block in a given search area as shown in Figure 9. In the example shown in Figure 9, the search area can be composed of R1: current CTU, R2: top left CTU, R3: top CTU, R4: left CTU. SAD can be used as a cost function.

[0125] Within each region, the decoder may search for a template that may have the SAD, eg, the smallest SAD, relative to the current template, and may use the corresponding block as the prediction block.

[0126] The dimensions of the regions, e.g., all regions (SearchRange_w, SearchRange_h), can be set proportional to the block dimensions (BlkW, BlkH) to result in a fixed number of SAD comparisons per pixel. For example, SearchRange_w is set as follows: SearchRange_w=a * BlkW. SearchRange_h can be determined as SearchRange_h=a * BlkH. For both, "a" may be a constant that adjusts the tradeoff between gain and complexity. For example, "a" may be equal to 5.

[0127] The intra template matching tool may be enabled, for example, for CUs with width and height sizes less than or equal to 64. This CU size, for example, the maximum CU size, for intra template matching may be configurable.

[0128] Spatial GPM (SGPM) in ECM may be supported. In this mode, several combinations of intra prediction modes and partitions may be tested on the reconstructed template. Figure 10 shows an example of SGPM template analysis for the construction of a candidate list.

[0129] In one example implementation, 26 partition modes may be tested. For each partition, three intra-prediction modes may be predefined. These modes may consist of an intra-prediction mode parallel to the partition direction and two modes derived from a template-based intra-mode derivation (TIMD) process. Overall, 78 combinations (e.g., 26×3=78) may be considered (as shown in Table 1 below). In each combination, the current partition may be used on the template and each combination of two modes may be tested. That is, for three modes, three modes may be tested (e.g., the first mode and the second mode, the first mode and the third mode, and finally the second mode and the third mode). The distance (SATD) between the reconstructed template and the prediction by the current partition may be calculated. The 16 candidates, e.g., the best candidate, each of which may include a partition mode and two intra-prediction modes, may be kept and put into an SGPM candidate list. The encoder may send information identifying an index to indicate which of the candidates may be selected depending on the rate-distortion analysis.

[0130] [Table 1]

[0131] Fusion for template-based intra mode derivation (TIMD) may be supported. For the current luma CB, for each intra prediction mode in the MPM list supplemented with the default mode, the SATD between the prediction of the template of this CB by that particular mode and the reconstructed sample of that template may be calculated. The two intra prediction modes with the smallest SATD may be selected as TIMD modes. For TIMD, the set of directional intra prediction modes may be expanded from 65 to 129 by inserting a direction between each arrow in FIG. 5. The set of possible intra prediction modes derived via TIMD may collect 131 modes. After keeping the two intra prediction modes obtained from the first round of testing with the MPM list supplemented with the default mode, for each of these two modes, if this mode is neither PLANAR nor DC, TIMD may also test the closest two of the extended directional intra prediction modes for the predicted SATD. The two TIMD modes obtained from the two tests may be weighted and fused after applying PDPC. Such weighted intra prediction may be used to code the current luma CB. The PDPC may be included in the derivation of the TIMD modes.

[0132] The costs of the two selected modes can be compared to a threshold. In this test, a cost factor of 2 is applied, i.e., costMode2<2 * costMode1 may be applied as follows: If this condition is true, fusion may be applied; otherwise, mode 1, e.g., only mode 1 may be used. The weights of the modes may be calculated from their SATD costs as follows: weight1=costMode2 / (costMode1+costMode2) weight2=1-weight1 The division may be performed using the same look-up table (LUT) based integerization scheme used by CCLM.

[0133] According to some procedures, chroma MTS may not be supported in VVC or ECM.

[0134] Chroma LFNST may be supported. LFNST may be applied to luma and chroma components. A CU flag, which may be named lfnst_idx, may be signaled to indicate the use of LFNST. LFNST may be allowed for, and may be allowed only for, dual trees for intra predicted CUs.

[0135] Systems, methods, and means are disclosed for encoding and decoding chroma blocks where direct mode (DM) intra prediction may be applied to the video data chroma blocks. If DM intra prediction is selected for one or more chroma blocks, prediction information specified for a corresponding luma block may be applied to the chroma blocks. An intra prediction mode specified for the luma block is determined to be applied to the chroma blocks. If the corresponding luma block is selected to be coded using DIMD and / or TIMD, the chroma block is determined to be coded using DIMD and / or TIMD as well. Transform information associated with the luma block may be applied to the corresponding chroma block. An MTS index associated with the luma block may be applied to the chroma block, and an LFNST index associated with the luma block may be applied to the corresponding chroma block.

[0136] The video encoder may be configured to determine that the chroma block may be encrypted and decoded in the same intra prediction mode as the corresponding luma block. The video encoder may be further configured to determine that the luma block and the corresponding chroma block may be processed using DIMD and / or TIMD. The video encoder may be configured to generate encoded video data including an indication to process the chroma block using DM intra prediction. The data may include a flag indicating to process the chroma block using DM intra prediction. The video data may further comprise data indicating that the corresponding luma block may be processed using DIMD, TIMD, IntraTMP, and / or SGPM. The video data may also comprise data indicating, for the luma block, a Low Frequency Non-Separable Transform (LFNST) index, a Multiple Transform Selection (MTS) index, and / or Multiple Reference Lines (MRL). The encoder may send the video data to a video decoder.

[0137] 11 illustrates an example of processing of transmitted data at a video decoder. The video decoder may be configured to receive video data and determine or identify chroma blocks within the video data. With reference to FIG. 11, at 910, the video decoder may determine from the received video data that direct mode (DM) intra prediction may be applied to the chroma blocks. For example, the video decoder may identify a flag within the video data indicating that DM intra prediction may be applied to the chroma blocks.

[0138] If the video decoder determines that DM intra processing is not applied to a particular chroma block, the decoder may determine at 912 to decode the chroma data using conventional chroma intra mode processing. As shown, the decoder may determine from the received video data the particular intra prediction mode used to encode the chroma block. The decoder may determine whether DC mode, planar mode, vertical mode, or horizontal mode was used to code the chroma block. At 914, the decoder may perform intra prediction using the identified one of the modes.

[0139] At 916, the decoder may decode low-frequency non-separable transform (LFNST) index data from the received data. If direct mode (DM) is not applied, LFNST may be performed on the chroma data if a flag, such as lfnst_idx, is signaled to indicate that LFNST may be applied to the chroma data. At 918, the decoder may use the LFNST index data to perform an inverse LFNST using output from intra prediction at 914.

[0140] At 920, the decoder may perform an inverse transform process on the output from the LFNST process at 918. If direct mode (DM) is not selected for use for a particular chroma block, the decoder may determine that multiple transform selection (MTS) is not used when processing the chroma block. Thus, as shown in Figure 11, the decoder may determine that the MTS index is set to 0, indicating that MTS processing may not be applied to the particular chroma block.

[0141] At 910, if the decoder determines from the received data that a direct mode (DM) intra-prediction mode is applied to the received chroma block, decoder processing may continue using intra-prediction data associated with the corresponding luma block. Conditional on the decoder determining that a DM intra-prediction mode is applied to the chroma block, the decoder may perform processing at 930, 914, 918, and 920. At 930, the decoder may retrieve the intra-prediction data associated with the corresponding luma block. As shown, the data for the corresponding luma block may specify an intra-prediction mode for that luma block, and may further specify whether decoder-side intra-mode derivation (DIMD) and / or template-based intra-mode derivation (TIMD) is applied to that luma block.

[0142] On the condition that the received video data indicates that DM intra prediction is applied to a particular chroma block, the decoder may perform 914 intra prediction of the particular chroma block using the retrieved data corresponding to the luma block. Thus, the decoder may apply to the chroma block the particular intra prediction mode selected for the corresponding luma block. If the retrieved data for the luma block indicates that a planar intra prediction mode is applied, the decoder may perform intra prediction using a planar mode. If the retrieved data for the luma block indicates that a DC mode is applied, the decoder may perform intra prediction using a DC mode. If the retrieved data for the luma block indicates that a horizontal mode is applied, the decoder may perform intra prediction using a horizontal mode.

[0143] If the data for the luma block indicates that DIMD or TIMD should be applied, the decoder may apply the selected DIMD or TIMD to the particular chroma block at 914. In the processing related to ECM, chroma DIMD may be used. The same process used for luma DIMD processing may be applied for chroma processing. A flag, e.g., an additional flag, may be sent or signaled by the encoder to indicate that chroma DIMD should be used. The flag may be signaled from the encoder to the decoder and may be retrieved from the received data at 930. The same method may be applied if chroma is coded in direct mode and luma is DIMD. DIMD for direct mode may improve the overall bitrate gain.

[0144] Two example implementations may be considered. A first example implementation may use a chroma DIMD process in the ECM, e.g., a readily available chroma DIMD process, which may derive the chroma mode from analyzing the luma for the two chroma channels. A second implementation may reuse the results of the luma DIMD. The luma DIMD process may use blending weights, e.g., predefined blending weights, to derive two modes that may be combined with the planar mode.

[0145] The first implementation may reuse the existing chroma DIMD architecture. However, the first implementation may be redundant with respect to chroma DIMD signaling. In other words, there may be two ways to signal chroma DIMD, one using chroma DIMD flags and the other using direct mode. Therefore, a second implementation may be considered in which a prediction, for example, a new prediction, may be obtained by blending three intra modes (for example, two derived modes and a planar mode).

[0146] TIMD may be enabled for a chroma block if the corresponding luma block is TIMD coded. Thus, if the data for the luma block indicates that TIMD is applied, the decoder may apply TIMD to the corresponding chroma block at 914. Chroma TIMD coding may improve compression and may do so without additional signaling to those selected for luma processing. TIMD processing may be performed as described herein.

[0147] Two example implementations may be considered. A first example implementation may use a TIMD process to derive a chroma mode, e.g., the best chroma mode, by testing possible modes, e.g., all possible modes, on a reconstructed template and selecting the one that minimizes the SATD between the reconstructed template and the predicted template. A second implementation may include reusing a TIMD mode derived from luma. The first implementation may be applied to both chroma components. However, the second implementation may have benefits derived from reusing pre-computed modes and combining them with pre-defined blending weights.

[0148] Referring to FIG. 11 , the retrieved intra prediction data for the luma block may indicate (e.g., at 930) a luma LFNST index, e.g., a transformation process. At 918, the decoder may apply the indicated LFNST to the chroma block. As discussed in connection with 916, if direct mode (DM) is not applied, LFNST may be performed on the chroma data if a flag, e.g., lfnst_idx, is signaled for the dual tree to indicate that LFNST may be applied to the chroma data. However, if direct mode (DM) intra prediction is applied, LFNST may be applied to the chroma data using the same index as that corresponding to the luma data. In this case, the flag lfnst_idx may not be signaled for LFNST to be applied to the chroma data.

[0149] The retrieved prediction data for the luma block may also indicate (e.g., at 930) a luma MTS index, e.g., a transform process. At 920, the decoder may use the luma MTS index to perform an inverse transform of the chroma block. If direct mode (DM) coding is applied to the chroma data, MTS may be enabled for chroma. The same transform pair selection as for luma data may be used for chroma. In ECM, the luma MTS may depend on the block size and intra mode. The chroma MTS may also depend on the block size and intra mode. However, the chroma may have a size other than that defined for the transform. That is, the chroma may be 2×N, N×2, or 2×2. In these and similar cases, the MTS may not be used and a DCT-II transform may be used, e.g., alternatively.

[0150] It will be appreciated that if direct mode (DM) is applied to the chroma data, the MRL index data associated with the luma block may also be used in chroma, and since a DM flag may be used to indicate the MRL, the MRL may be enabled without additional signaling.

[0151] IntraTMP may be adopted. If the co-located luma block uses IntraTMP (e.g., at 930), it may be determined to apply chroma IntraTMP in case of direct mode. An embodiment may be considered in which IntraTMP is recalculated for chroma components (intraTMP is calculated for Cb and Cr, or they are calculated at once) and an embodiment in which luma IntraTMP is reused for luma component. The first implementation may provide flexibility, e.g., the highest flexibility, which may lead to higher computational complexity compared to the second implementation.

[0152] SGPM may be adopted. If the co-located luma block uses SGPM (e.g., at 930), it may be determined to apply SGPM in the case of direct mode. An embodiment may be considered in which the SGPM is recalculated for the chroma components (calculating the best two intra modes and separation lines for each or both components) and in which the luma SGPM is reused for the chroma components (reusing the luma 2 intra modes and separation lines for each component). The first implementation may provide flexibility, e.g., the highest flexibility, which may lead to higher computational complexity compared to the second implementation.

[0153] A transform copy flag may be employed. A single flag, e.g., a direct mode flag, may be employed to signal transform and prediction information. The signaling may be separated and two flags may be used. A direct mode flag may be used to copy the luma intra prediction mode and a second flag may be used to copy the transform information. The use of two flags may provide additional flexibility to the encoder to choose to copy either the prediction information or the transform information.

[0154] Although features and elements are described herein in certain combinations, one skilled in the art will understand that each feature or element may be used alone or in any combination with the other features and elements. In addition, the methods described herein may be implemented in a computer program, software, or firmware embodied 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 memory devices, magnetic media such as internal hard disks and removable disks, magneto-optical media, and optical media such as CD-ROM disks and Digital Versatile Disks (DVDs). A processor in association with software may be used to implement a radio frequency transceiver for use in a WTRU, UE, terminal, base station, RNC, or any host computer.

Claims

1. A decoding device, comprising: a processor, the processor comprising: Get the video data determining a chroma block from the video data; determining, based on the video data, that a direct mode (DM) is applied to the chroma block; based on a determination that DM is applied to the chroma block, retrieving data associated with a luma block associated with the chroma block, the data indicative of a prediction process; configured to apply the prediction process to the chroma blocks; Device.

2. 2. The apparatus of claim 1, wherein the processor configured to determine that DM is applied to the chroma block is further configured to determine that DM is applied to the chroma block based on a flag in the video data.

3. the prediction process includes decoder-side intra mode derivation (DIMD); 2. The apparatus of claim 1.

4. the prediction process includes template-based intra-mode derivation (TIMD); 2. The apparatus of claim 1.

5. The prediction process includes intra-template matching prediction (IntraTMP); 2. The apparatus of claim 1.

6. the prediction process includes spatial geometric prediction mode (SGPM) prediction; 2. The apparatus of claim 1.

7. the prediction process includes multi-reference line (MRL) prediction; 2. The apparatus of claim 1.

8. The processor, Based on the determination that a DM is applied to the chroma block, retrieve data associated with the luma block indicative of a transformation process; and further configured to apply the transformation process to the chroma blocks.

2. The apparatus of claim 1.

9. The apparatus of claim 8 , wherein the transformation process is multiple transform selection (MTS).

10. The apparatus of claim 8 , wherein the transformation process is a low-frequency non-separable transform (LFNST).

11. The apparatus according to any one of claims 1 to 10, wherein the device is a radio transmitting / receiving unit.

12. The device according to any one of claims 1 to 10, wherein the device is a video decoder.

13. The apparatus of any one of claims 1 to 10, further comprising a computing memory communicatively coupled to the processor.

14. 1. A method of decryption comprising the steps of: Obtaining video data; and determining chroma blocks from the video data; determining, based on the video data, that a direct mode (DM) is applied to the chroma block; based on a determination that DM is applied to the chroma block, retrieving data associated with a luma block associated with the chroma block, the data being indicative of a prediction process; applying the prediction process to the chroma blocks. method.

15. determining that DM is applied to the chroma block further includes determining that DM is applied to the chroma block based on a flag in the video data. The method of claim 14.

16. the prediction process includes decoder-side intra mode derivation (DIMD); The method of claim 14.

17. the prediction process includes template-based intra-mode derivation (TIMD); The method of claim 14.

18. The prediction process includes intra-template matching prediction (IntraTMP); The method of claim 14.

19. the prediction process is spatial geometric prediction mode (SGPM); The method of claim 14.

20. the prediction process includes multi-reference line (MRL) prediction; The method of claim 14.

21. retrieving data indicative of a transformation process associated with the luma block based on the determination that the DM is applied to the chroma block; and applying the transformation process to the chroma blocks. The method of claim 14.

22. 22. The method of claim 21, wherein the transformation process is multiple transform selection (MTS).

23. The method of claim 21 , wherein the transformation process is a low-frequency non-separable transform (LFNST).

24. A computer readable medium comprising instructions for causing one or more processors to perform the method of any one of claims 14 to 23.

25. 1. An encoding device, comprising: The method further comprises: determining that a luma block associated with the chroma block should be decoded using a prediction process associated with the luma block; generating an indication that a direct mode (DM) is to be applied to the chroma block; generating video data including the chroma block, the indication that a DM is applied to the chroma block, the luma block, and data indicating that the luma block is associated with the prediction process; configured to transmit the video data; Device.

26. 26. The apparatus of claim 25, wherein the indication that DM is applied to the chroma block comprises a flag.

27. the prediction process includes decoder-side intra mode derivation (DIMD); 26. The apparatus of claim 25.

28. the prediction process includes template-based intra-mode derivation (TIMD); 26. The apparatus of claim 25.

29. The prediction process includes intra-template matching prediction (IntraTMP); 26. The apparatus of claim 25.

30. the prediction process comprises spatial geometric prediction mode (SGPM) prediction; 26. The apparatus of claim 25.

31. the prediction process includes multi-reference line (MRL) prediction; 26. The apparatus of claim 25.

32. the video data further comprising data indicating that the luma block is associated with a transformation process.

26. The apparatus of claim 25.

33. 33. The apparatus of claim 32, wherein the transformation process is multiple transform selection (MTS).

34. 33. The apparatus of claim 32, wherein the transformation process is a low-frequency non-separable transform (LFNST).

35. Apparatus according to any one of claims 25 to 34, wherein the device is a radio transmitting / receiving unit.

36. An apparatus according to any one of claims 25 to 34, wherein the apparatus is a video decoder.

37. The apparatus of any one of claims 25 to 34, further comprising a computing memory communicatively coupled to the processor.

38. 1. A method of encoding, comprising: determining that a chroma block should be decoded using a prediction process associated with a luma block associated with the chroma block; generating an indication that a direct mode (DM) is applied to the chroma block; generating video data including the chroma block, the indication that a DM is applied to the chroma block, the luma block, and data indicating that the luma block is associated with the prediction process; and transmitting the video data. method.

39. 40. The method of claim 38, wherein the indication that DM is applied to the chroma block comprises a flag.

40. the prediction process includes decoder-side intra mode derivation (DIMD); 39. The method of claim 38.

41. the prediction process includes template-based intra-mode derivation (TIMD); 39. The method of claim 38.

42. The prediction process includes intra-template matching prediction (IntraTMP); 39. The method of claim 38.

43. the prediction process comprises spatial geometric prediction mode (SGPM) prediction; 39. The method of claim 38.

44. the prediction process includes multi-reference line (MRL) prediction; 39. The method of claim 38.

45. the video data further comprising data indicating that the luma block is associated with a transformation process.

39. The method of claim 38.

46. 46. ​​The method of claim 45, wherein the transformation process is multiple transform selection (MTS).

47. 46. ​​The method of claim 45, wherein the transformation process is a low-frequency non-separable transform (LFNST).

48. An electromagnetic signal carrying computer readable instructions for carrying out a method according to any one of claims 38 to 47.

49. A computer readable medium comprising instructions for causing one or more processors to perform the method of any one of claims 38 to 47.

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