Most Probable Mode List Generation with Template-Based Intra-Mode Derivation and Decoder-Side Intra-Mode Derivation

Abstract

Systems, methods, and means are disclosed for Most Probable Mode (MPM) list generation using template-based intra mode derivation (TIMD). An example method involves determining that an intra-coding mode derivation process is enabled for a first coding block, generating a first MPM list for the first coding block based on the intra-coding mode derivation process being enabled for the first coding block based on a first MPM list generation process, decoding the first coding block based on the first MPM list, determining that the intra-coding mode derivation process is disabled for a second coding block, generating a second MPM list for the second coding block based on a second MPM list generation process different from the first MPM list generation process based on the intra-coding mode derivation process being disabled for the second coding block, and decoding the second coding block based on the second MPM list.

Description

[Technical field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of European Provisional Patent Application No. 21306876.0, filed December 21, 2021, and European Provisional Patent Application No. 22305023.8, filed January 12, 2022, the contents of which are incorporated herein by reference. [Background technology]

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

[0003] Systems, methods, and means may be provided for most probable mode (MPM) list generation using different MPM list generation processes for different coding blocks. For example, a device for video decoding may select an MPM generation process for a coding block from multiple MPM list generation processes. The device may base the selection on whether an intra-coding mode derivation process is enabled for the coding block. Based on the intra-coding mode derivation process being enabled for the coding block, an MPM list for the coding block may be generated based on a first MPM list generation process. Based on the intra-coding mode derivation process being disabled for the coding block, an MPM list for the coding block may be generated based on a second, different MPM list generation process.

[0004] A device for video encoding may select an MPM generation process for a coding block from multiple MPM list generation processes. The device may base the selection on whether an intra-coding mode derivation process is enabled for the coding block. Based on the intra-coding mode derivation process being enabled for the coding block, an MPM list for the coding block may be generated based on a first MPM list generation process. Based on the intra-coding mode derivation process being disabled for the coding block, an MPM list for the coding block may be generated based on a second, different MPM list generation process.

[0005] In one embodiment, the MPM list generation process, the candidate intra-prediction modes may be modes generated based on intra-prediction modes associated with neighboring blocks of the coding block. One or more decoder-side intra mode derivation (DIMD) candidates may be derived for the coding block based on a histogram of gradients associated with reconstructed pixels neighboring the coding block. The candidate intra-prediction modes and DIMD candidates are added to an MPM list for the coding block. In an example MPM list generation process, the candidate intra-prediction modes may be generated based on intra-prediction modes associated with neighboring blocks of the coding block, and derivation of the candidate modes via DIMD may be bypassed. In an example MPM list generation process, the candidate intra-prediction modes include TIMD derivation modes and DIMD derivation modes. For example, the MPM list may include intra-prediction modes associated with neighboring blocks of the coding block, one intra mode derivation (TIMD) derivation mode, and / or one DIMD derivation mode. For example, intra-prediction modes may be tested for reconstructed pixels neighboring the first coding block, and a candidate intra-prediction mode may be selected from the candidate intra-prediction modes based on the testing. The selected candidate intra-prediction mode may be added to the MPM list. A DIMD candidate may be derived based on a histogram of gradients associated with reconstructed samples neighboring the coding block, and the DIMD candidate may be added to the MPM list (e.g., in addition to the selected candidate intra-prediction mode).

[0006] For example, the intra-coding mode derivation process based on which the device may select the MPM list generation process may include a template-based process. For example, the intra-coding mode derivation process may include TIMD. The TIMD may include testing a plurality of candidate intra-prediction modes in the MPM list for reconstructed pixels neighboring the coding block, and selecting a candidate intra-prediction mode from the candidate intra-prediction modes based on the testing. Based on TIMD being enabled for the coding block, the MPM list may be generated with DIMD bypassed. Based on TIMD being disabled for the coding block, the MPM list may be generated with DIMD.

[0007] For example, an intra-coding mode derivation process that a device may use to select an MPM list generation process may be associated with combined intra-inter prediction (CIIP). Based on CIIP being enabled for a coding block, an MPM list may be generated with DIMD bypassed. Based on TIMD being disabled for a coding block, an MPM list may be generated with DIMD.

[0008] The systems, methods, and means described herein 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. 1A is a system diagram illustrating an example communication system in which one or more disclosed embodiments may be implemented. [Figure 1B] FIG. 1B is a system diagram illustrating an example wireless transmit / receive unit (WTRU) that may be used within the communications system illustrated in FIG. 1A, according to one embodiment. [Figure 1C] FIG. 1C is a system diagram illustrating an example radio access network (RAN) and an example core network (CN) that may be used within the communications system illustrated in FIG. 1A, according to one embodiment. [Figure 1D] FIG. 1D is a system diagram illustrating a further exemplary RAN and a further exemplary CN that may be used within the communications system illustrated in FIG. 1A, according to one embodiment. [Diagram 2] FIG. 2 illustrates an exemplary video encoder. [Diagram 3] FIG. 3 illustrates an exemplary video decoder. [Figure 4] FIG. 4 illustrates an example of a system in which various aspects and embodiments may be implemented. [Diagram 5] FIG. 5 shows an example of matrix weighted intra prediction (MIP). [Figure 6] FIG. 6 may show an example of neighboring blocks of a current coding unit (CU). [Figure 7] FIG. 7 illustrates an example of including two modes generated from template-based intra mode derivation (TIMD) in a most probable mode (MPM) list. [Figure 8] FIG. 8 illustrates an example MPM list for a TIMD and an example general MPM list. 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 communications system 100 in which one or more disclosed embodiments may be implemented. Communications system 100 may be a multiple access system that provides content, such as voice, data, video, messaging, broadcasts, etc., to multiple wireless users. Communications 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, 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 WTRUs 102a, 102b, 102c, and 102d may be referred to interchangeably as a UE.

[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 transceiver station (BTS), a NodeB, an eNodeB, a home NodeB, a home eNodeB, a gNB, a NR NodeB, a site controller, an access point (AP), a wireless router, etc. Although the base stations 114a, 114b are each depicted 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 over an air interface 116, which may be any suitable wireless communication link (e.g., radio frequency (RF), microwave, centimeter wave, micrometer wave, infrared (IR), ultraviolet (UV), visible light, etc.). The air interface 116 may be established using any suitable radio access technology (RAT).

[0016] More specifically, as noted above, the communications system 100 may be a multiple access system and may employ one or more channel access schemes, such as CDMA, TDMA, FDMA, OFDMA, SC-FDMA, 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 transmitted to / 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 Node B, a Home eNode B, 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 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 the transmission control protocol (TCP), the user datagram protocol (UDP), and / or the 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 use a cellular-based wireless technology, and a base station 114b, which may use an IEEE 802 wireless technology.

[0025] 1B is a system diagram illustrating an example WTRU 102. As shown in FIG. 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 depicts 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 signals to or receive signals 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 use 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 a speaker / microphone 124, a keypad 126, and / or a display / touchpad 128 (e.g., a liquid crystal display (LCD) display device or an organic light-emitting diode (OLED) display device), which may receive user-entered data from the speaker / microphone 124, the keypad 126, and / or the display / touchpad 128. 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 in 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 position information (e.g., longitude and latitude) regarding a current location of the WTRU 102. In addition to or in lieu of information from the GPS chipset 136, the WTRU 102 may receive position 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 being received from two or more nearby base stations. It will be appreciated that the WTRU 102 may obtain position 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 the 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 the processor 118). In one embodiment, the WRTU 102 may include a half-duplex radio for the 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 communicate with the WTRUs 102a, 102b, 102c over the air interface 116 using E-UTRA radio technology. The RAN 104 may also communicate with the CN 106.

[0036] The RAN 104 may include eNode-Bs 160a, 160b, 160c, although it will be understood that the RAN 104 may include any number of eNode-Bs while remaining consistent with an embodiment. The eNode-Bs 160a, 160b, 160c may each include one or more transceivers for communicating with the WTRUs 102a, 102b, 102c over the air interface 116. In an embodiment, the eNode-Bs 160a, 160b, 160c may implement MIMO technology. Thus, the eNode-B 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 eNode-Bs 160a, 160b, 160c may be associated with a particular cell (not shown) and may be configured to handle radio resource management decisions, handover decisions, user scheduling, etc. in the UL and / or DL. As shown in FIG 1C, the eNode-Bs 160a, 160b, 160c may communicate with each other 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 depicted as part of the CN 106, it will be understood that any of these elements may be owned and / or operated by an entity other than the CN operator.

[0039] The MME 162 may be connected to each of the eNode-Bs 162a, 162b, 162c in the RAN 104 via an S1 interface and may 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 / from the WTRUs 102a, 102b, 102c. The SGW 164 may perform other functions, such as anchoring the user plane during inter-eNode B handover, triggering paging when DL data is available to the WTRUs 102a, 102b, 102c, managing and storing the context of the WTRUs 102a, 102b, 102c, etc.

[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 communicate with an IP gateway (e.g., an IP multimedia subsystem (IMS) server) that serves as an interface between the CN 106 and the PSTN 108. In addition, the CN 106 may provide the WTRUs 102a, 102b, 102c with access to 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 illustrated in FIGS. 1A-1D as a wireless terminal, it is contemplated that in certain representative embodiments such a terminal may use a wired communications interface with the communications network (e.g., temporarily or permanently).

[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 STAs may arrive through the AP and be delivered to the STAs. Traffic originating from the STAs to destinations outside the BSS may be sent to the AP and delivered to the respective destination. Traffic between STAs in 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 in the BSS may be considered and / or referred to as peer-to-peer traffic. Peer-to-peer traffic may be sent in a Direct Link Setup (DLS) between the source STA and the destination STA (e.g., directly between them). 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 the STAs (e.g., all of the STAs) within or using the IBSS may communicate directly with each other. The IBSS mode of communication may 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 an operating channel of the BSS and 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 active 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 20 MHz primary 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 coding, the data may pass through a segment parser, which 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 communication coverage areas. MTC devices may have limited functionality, including specific functions, for example, support for (e.g., support only for) specific and / or limited bandwidths. MTC devices may include a battery with a battery life above a threshold (e.g., to maintain a 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 designated 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 set by the STA and / or limited 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) the 1 MHz mode, even if the AP and other STAs in the BSS support 2 MHz, 4 MHz, 8 MHz, 16 MHz, and / or other channel bandwidth operating modes. Carrier sensing and / or Network Allocation Vector (NAV) settings may depend on the state 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 band that can be used by 802.11ah is 902MHz to 928MHz. In South Korea, the available frequency band is 917.5MHz to 923.5MHz. In Japan, the available frequency band is 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 communicate with the WTRUs 102a, 102b, 102c over the air interface 116 using NR radio technology. 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 wireless signals to and / or receive wireless signals 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, and 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 value configurations. 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., eNode-Bs 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 eNode-B 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 eNode-Bs 160a, 160b, 160c substantially simultaneously. In a non-standalone configuration, the eNode-Bs 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 depicted as part of the CN 115, it will be understood that any of these elements may be owned and / or operated by an entity other than the CN operator.

[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, eNode-Bs 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 implement 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 of the 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 of the 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 use terrestrial wireless communication to implement the tests.

[0064] 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 undeployed (e.g., test) wired and / or wireless communication networks to implement testing of one or more components. 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, approaches, and the like. Many of these aspects are described with specificity and often 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, aspects may similarly 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 5-8 described herein may provide some examples, but other examples are contemplated. Discussion of Figures 5-8 is not intended to limit the scope of implementations. At least one of the aspects relates generally to video encoding and decoding, and at least one other aspect relates generally 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 actions for achieving the described method. Unless a specific order of steps or actions is required for proper operation of the method, the order and / or use of specific steps and / or actions may be modified or combined. In addition, 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 a modified ordering of 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 an overlapping time with the second decode.

[0069] Various methods and other aspects described in the present application 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. Furthermore, the subject matter disclosed herein may be applied to any type, format, or version of video coding, whether described in a standard or recommendation, whether existing or developed in the future, and whether an extension of any such standard and recommendation. Unless otherwise indicated or technically impossible, the aspects described in the present application may be used individually or in combination.

[0070] In the embodiments described in this application, various numerical values ​​are used, such as 2, 4, 6, 8, 16, 22, 32, 64, etc. These and other specific values ​​are for purposes of illustrating the embodiments, and the described aspects are not limited to these specific values.

[0071] 2 illustrates an exemplary video encoder. Although variations of the exemplary encoder 200 are contemplated, the encoder 200 is described below for purposes of clarity without describing all possible 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., 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] In the encoder 200, a picture is coded by the encoder elements, as described below. 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 decides (205) whether to use intra mode or inter mode to code the unit, and indicates the intra / inter decision, for example, by a prediction mode flag. A prediction residual is calculated (210), for example, by subtracting the predicted block from the original image block.

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

[0075] The encoder decodes the coded block to provide a reference for further prediction. The quantized transform coefficients are dequantized (240) and inverse transformed (250) to decode the prediction residual. The decoded prediction residual and the predicted block are combined (255) 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. The filtered image is stored in a reference picture buffer (280).

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

[0077] In particular, the decoder 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 the picture according to the decoded picture partition information (335). The transform coefficients are inverse quantized (340) and inverse transformed (350) to decode the prediction residual. The decoded prediction residual and the predicted block are combined (355) to reconstruct an image block. The predicted block may be obtained from intra prediction (360) or from motion compensated prediction (i.e., inter prediction) (375) (370). An in-loop filter (365) is applied to the reconstructed image. The filtered image is stored in a reference picture buffer (380).

[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 below 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 implement 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 can 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., a volatile memory device and / or a non-volatile memory device). The system 400 includes a storage device 440, which can include non-volatile memory and / or volatile memory, including, but not limited to, Electrically Erasable Programmable Read-Only Memory (EEPROM), Read-Only Memory (ROM), Programmable Read-Only Memory (PROM), Random Access Memory (RAM), Dynamic Random Access Memory (DRAM), Static Random Access Memory (SRAM), Flash, magnetic disk drives, and / or optical disk drives. Storage devices 440 may include, by way of non-limiting example, internal storage devices, attached storage devices (including removable and non-removable storage devices), and / or network-accessible storage devices.

[0081] The system 400 includes an encoder / decoder module 430 configured to process data to provide, for example, encoded or decoded video, and the encoder / decoder module 430 may include its own processor and memory. 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, as is known to those skilled in the art.

[0082] Program code to be loaded into the processor 410 or the encoder / decoder 430 to implement various aspects described herein may be stored in the storage device 440 and then loaded onto 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 various items during execution 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 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 can 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, for example, 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 a variety of input devices, as shown in block 445. Such input devices may include, but are not limited to, (i) a radio frequency (RF) section that receives, for example, RF signals transmitted over the air by a broadcast station, (ii) a component (COMP) input (or a set of COMP inputs), (iii) a universal serial bus (USB) input, and / or (iv) a High Definition Multimedia Interface (HDMI) input. Other examples include composite video, not shown in FIG. 4.

[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 appropriate elements to (i) select a desired frequency (also referred to as selecting a signal or band-limiting a signal to a frequency band), (ii) down-convert the selected signal, (iii) band-limit again to a narrower frequency band to select a signal frequency band, which in a particular embodiment may be referred to (for example) as a channel, (iv) demodulate the down-converted and band-limited signal, (v) perform error correction, and / or (vi) demultiplex 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, for example, a tuner to perform various of these functions, including down-converting a received signal to a lower frequency (e.g., an intermediate frequency or a frequency close to baseband) or to baseband. In one embodiment of a set-top box, the RF section and its associated input processing elements perform frequency selection by receiving, filtering, downconverting, and refiltering RF signals transmitted over a wired (e.g., cable) medium 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 may 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] 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, e.g., Reed-Solomon error correction, may be implemented, for example, in a separate input processing IC or within 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 within the processor 410, as desired. The demodulated, error corrected, and demultiplexed streams are provided to various processing elements, including, for example, the processor 410 and an encoder / decoder 430 operating in combination with memory and storage elements that process the data streams 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 a suitable connection arrangement 425, such as an internal bus known in the art, including an Inter-IC (I2C) bus, hardwired, 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, but is not limited to, a modem or a network card, and communication channel 460 may be implemented in a wired and / or wireless medium, for example.

[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 provides data through an HDMI connection of input block 445. Still other embodiments provide streamed data to system 400 using an RF connection of input block 445. As noted above, various embodiments provide data in a non-streaming manner. In addition, various embodiments use wireless networks other than Wi-Fi, e.g., a cellular network or a Bluetooth network.

[0090] The system 400 can 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 can be for a television, a tablet, a laptop, a mobile phone, or other device. The display 475 can also be integrated with other components (e.g., as in a smart phone) or can 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 executed 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. "Decoding" as used herein can encompass all or part of the processes performed on a received encoded sequence to generate a final output suitable for display, for example. 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 a decoder of various implementations described in this application, such as determining that an intra-coding mode derivation process is enabled for the first coding block based on the intra-coding mode derivation process being enabled for the first coding block, generating a first most probable mode (MPM) list for the first coding block based on a first MPM list generation process, decoding the first coding block based on the first MPM list, determining that the intra-coding mode derivation process is disabled for the second coding block based on the intra-coding mode derivation process being disabled for the second coding block, generating a second MPM list for the second coding block based on a second MPM list generation process different from the first MPM list generation process, and decoding the second coding block based on the second MPM list, etc.

[0095] As a further example, in one embodiment, "decoding" refers to only entropy decoding, while in another embodiment, "decoding" refers to only differential decoding, while in another embodiment, "decoding" refers to a combination of entropy decoding and differential decoding. Whether the phrase "decoding process" is intended to refer to a task subset specifically 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 one of ordinary skill in the art.

[0096] Various implementations involve encoding. Similar to the above discussion of "decoding," "encoding" as used in this application 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 partitioning, differential encoding, transforming, quantization, and entropy encoding. In various embodiments, such processes may also or alternatively include processes performed by encoders of various implementations described in this application, such as determining that an intra-coding mode derivation process is enabled for the first coding block based on the intra-coding mode derivation process being enabled for the first coding block, generating a first most probable mode (MPM) list for the first coding block based on a first MPM list generation process, encoding the first coding block based on the first MPM list, determining that the intra-coding mode derivation process is disabled for the second coding block based on the intra-coding mode derivation process being disabled for the second coding block, generating a second MPM list for the second coding block based on a second MPM list generation process different from the first MPM list generation process, and encoding the second coding block based on the second MPM list, etc.

[0097] 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 to a task subset specifically 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.

[0098] It should be noted that the coding syntax used herein to indicate syntax elements, e.g., primary most probable mode (PMPM), DIMD, TIMD, secondary most probable mode (SMPM), etc., are descriptive terms and therefore do not exclude the use of other syntax element names.

[0099] 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.

[0100] 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. The method may be implemented, for example, in a processor, where a processor 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, for example, communication devices, such as computers, mobile phones, portable / personal digital assistants ("personal digital assistants," PDAs), and other devices that facilitate communication of information between end users.

[0101] References to "one embodiment" or "an embodiment" or "one implementation" or "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 embodiment" or "in an embodiment" or "in one implementation" or "in an implementation" appearing in various places throughout this application, as well as any other variations thereof, are not necessarily all referring to the same embodiment.

[0102] 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.

[0103] 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.

[0104] 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, for example, an operation such as storing information, processing information, transmitting information, moving information, copying information, erasing information, calculating information, determining information, predicting information, or estimating information.

[0105] 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 listed alternative (A), or the selection of only the second listed 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 listed alternative (A), or the selection of only the second listed alternative (B), or the selection of only the third listed alternative (C), or the selection of only the first and second listed alternatives (A and B), or the selection of only the first and third listed alternatives (A and C), or the selection of only the second and third listed alternatives (B and C), or the selection of all three alternatives (A and B and C). This may be expanded as many times as the number of items listed, as would be apparent to one of ordinary skill in the art and related arts.

[0106] Also, as used herein, the term "signaling" specifically means to indicate something to a corresponding decoder. The encoder signal may include, for example, an indication such as PMPM, DIMD, TIMD, SMPM, etc. In this way, in one embodiment, the same parameters are used at 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 manners. For example, in various embodiments, one or more syntax elements, flags, etc. are used to signal information to a corresponding decoder. The above relates to the verb form of the word "signal", which may also be used as a noun in this specification.

[0107] 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 signal that the signal carries may be, for example, analog or digital information. The signal may be transmitted by a variety of different wired or wireless links, as is known. The signal may be stored in, accessed from, or received from a processor-readable medium.

[0108] Many examples are described herein. The features of the examples may be provided alone or in any combination across various claim categories and types. Furthermore, an example 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, the 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, the features described herein may be realized by generating and / or transmitting and / or receiving and / or decoding a bitstream or signal. For example, the features described herein may be realized as a method, a process, an apparatus, a medium that stores instructions, a medium that stores data, or a signal. For example, the 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.

[0109] In intra-coding, one or more most probable mode (MPM) lists may be generated. The MPM list may include the most probable candidate modes for a coding block, such as a prediction unit (PU) (e.g., the current PU). In some embodiments, the MPM list may include candidate intra-prediction modes derived via template-based intra-mode derivation (TIMD).

[0110] The encoder may select a prediction mode (e.g., the best prediction mode of a list of prediction modes). The encoder may signal an index of the selected prediction mode to a decoder to perform the same prediction. The encoder may select a set of most probable modes. For example, two MPM lists may be used, where the first list may include 6 MPMs and the second list may include 16 MPMs.

[0111] Decoder-side intra mode derivation (DIMD) and / or TIMD may be performed to derive candidate intra prediction modes for a coding block. For example, reconstructed pixels (e.g., template pixels) surrounding the current block may be used to derive the intra prediction mode. For example, template samples in the upper and left directions may be used to derive the intra prediction mode. In DIMD, the reconstructed template samples may be analyzed to estimate the template directionality. Based on the estimated directionality of the template, one or more directional modes, such as two directional modes, may be selected. A prediction signal for the current block may be generated from mixing these two modes with a planar mode.

[0112] For example, in DIMD, two intra modes may be derived from reconstructed adjacent samples. The two intra modes (e.g., predictors) may be combined with a planar mode predictor with weights derived from gradients. The division operation in the weight derivation may be performed utilizing a lookup table (LUT)-based integerization scheme (e.g., the scheme used by the cross-complaint linear model (CCLM)). For example, the division operation in the orientation calculation (A) Orient=Gy / Gx may be calculated by the following exemplary 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}.

[0113] The derived intra modes may be included in an MPM list, such as a primary MPM list, and the DIMD process may be performed before the MPM list is built. The primary derived intra modes of a DIMD block may be stored with the block and may be used for MPM list construction of neighboring blocks. In an embodiment, the MPM list may include modes generated from the DIMD.

[0114] In TIMD, intra-prediction modes may be tested against a template of reconstructed pixels (e.g., reconstructed pixels neighboring the current block). One or more candidate intra-prediction modes may be selected from the tested modes (e.g., based on the testing). For example, the two best modes (e.g., the modes that minimize the sum of absolute transform difference (SATD) between the template of the reconstructed pixel and its prediction) may be selected. A prediction signal may be generated from blending these two modes.

[0115] Figure 5 shows an example of matrix weighted intra prediction (MIP). To predict samples of a rectangular block of width W and height H, MIP may take as input one line of H reconstructed adjacent boundary samples to the left of the block and one line of W reconstructed adjacent boundary samples above the block. In an example, if reconstructed samples are not available, predicted samples may be used as input. The generation of the prediction signal may be based on averaging, matrix vector multiplication, and linear interpolation, as shown with respect to Figure 5.

[0116] Of the boundary samples, 4 or 8 samples may be selected by averaging based on the block size and / or shape. top and bdry left is a smaller boundary sample by averaging adjacent boundary samples according to a given rule that depends on the block size.

[0117]

number

[0118]

number

[0119]

number

[0120] The matrix multiplication may include a matrix vector multiplication, for example followed by an offset addition that may be performed using the averaged samples as input. The result may be a reduced prediction signal for a subsampled set of samples in the original block. The reduced input vector bdry red from the reduced prediction signal pred red (For example, width W red and height H red In this case, W red and H red It can be defined as:

[0121]

number

[0122] The reduced prediction signal pred red can be calculated by taking the matrix vector product and adding an offset. pred red =A·bdry red +b

[0123] In this case, the matrix A is W red H red The parameter b may be or may contain a matrix with rows and four columns if W=H=4, and eight columns in all other cases. red H red The matrix A and the offset vector b may be taken from one of the sets S0, S1, S2. The index idx=idx(W,H) is obtained as follows:

[0124]

number

[0125] In such a case, the coefficients of the matrix A can be represented with 8-bit precision. The set S0 includes 16 matrices

[0126]

number

[0127]

number

[0128]

number

[0129]

number

[0130]

number

[0131]

number

[0132] Interpolation may be used, for example, to generate a prediction signal at the remaining positions. The prediction signal at the remaining positions may be generated from the prediction signal on the subsampled set by linear interpolation, which may be, for example, a single-step linear interpolation in several directions. The interpolation may be performed horizontally and vertically. For example, the interpolation may be performed first horizontally and then vertically (e.g., regardless of block shape or block size).

[0133] Signaling of MIP mode and coordination with other coding tools may be provided. For an intra mode CU, a flag indicating whether to apply MIP mode may be included in the video data (e.g., video bitstream). If MIP mode is applied, MIP mode (predModeIntra) may be signaled. For MIP mode, a transposition flag (isTransposed) (which may indicate, e.g., whether the mode is transposed) and a MIP mode Id (modeId) (which may indicate, e.g., which matrix to use for a given MIP mode) may be derived as follows: isTransposed=predModeIntra&1 modeId=predModeIntra>>1

[0134] MIP coding modes can be harmonized with other coding tools by considering one or more of the following: enabling low-frequency non-separable transform (LFNST) for MIP on large blocks (e.g., using LFNST transform in planar mode), performing reference sample derivation for MIP exactly as for conventional intra prediction modes, using original reference samples instead of downsampled ones for upsampling used in MIP prediction, performing clipping before upsampling instead of after, allowing MIP up to 64x64 regardless of the maximum transform size, or making the number of MIP modes 32 for sizeId=0, 16 for sizeId=1, and 12 for sizeId=2.

[0135] One or more MPM lists may be used. In an embodiment, two MPM lists may be generated: a primary MPM (PMPM) list and a secondary MPM (SMPM) list. The PMPM list may include six entries (e.g., six MPMs) and the SMPM list may include sixteen entries (e.g., six MPMs). A general MPM list (e.g., comprising the PMPM list and the SMPM list) may be constructed with 22 entries. The first entry may be a planar mode. The other entries may be obtained from intra modes of the left (L), top (A), bottom-left (BL), top-right (AR), and top-left (AL) neighboring blocks. Directional modes with additional offsets from the first two available directional modes of the neighboring blocks may be included in the MPM list. One or more predefined (e.g., additional) default modes may be included in the MPM list. A redundancy check may be performed before adding an entry to the MPM list. For example, in generating the 22-entry general MPM list described herein, when a given intra-prediction mode index (e.g., the index of an intra-prediction mode selected to predict the bottom-left luminance CB) is proposed for addition to the current list of MPMs and the proposed index is already present in the current list, the addition of the proposed index may be skipped.

[0136] The PMPM may be constructed from the first six entries in the general MPM (e.g., the first six MPMs). The other entries (e.g., the rest of the entries) may form the SMPM list.

[0137] Figure 6 shows the neighboring blocks of a current CU. As shown in Figure 6, block A may be the upper neighboring block, block AR may be the top right neighboring block, block AL may be the top left neighboring block, block L may be the left neighboring block, and block BL may be the bottom left neighboring block.

[0138] A syntax element corresponding to the PMPM list may be signaled in the bitstream. In an embodiment, if the PMPM indication is equal to one, an index in the PMPM list may be parsed to determine the intra-prediction mode. In an embodiment, if the PMPM indication is equal to zero, another syntax element may be signaled for the SMPM list, and a second syntax element may be signaled to indicate an index in the SMPM list.

[0139] For a given coding block, an MPM list generation process may be used to generate an MPM list for that coding block. MPM list generation may be performed using different MPM list generation processes for different coding blocks. For example, the MPM list generation process may be determined / selected based on whether an intra-coding mode derivation process is enabled for the coding block. For example, the intra-coding mode derivation process may be TIMD.

[0140] The device may determine that the intra-coding mode derivation process is disabled (e.g., not used in MPM list generation) for a coding block. In this case, a first MPM list generation process may be used to generate an MPM list for that coding block. For example, the first MPM list generation process may involve using DIMD for MPM list generation (e.g., based on the intra-coding mode derivation process being disabled). For example, for a given coding block, a candidate intra-prediction mode may be derived based on intra-prediction modes associated with neighboring blocks of the coding block. As part of the MPM list generation process, a DIMD candidate may be derived based on a histogram of gradients associated with reconstructed pixels neighboring the coding block. The candidate intra-prediction modes and / or DIMD candidates may be added to an MPM list for the coding block. The coding block may be decoded based on (e.g., using) the generated MPM list. In an embodiment, the DIMD may generate two directional modes (e.g., in addition to a planar mode), and the first and second modes may be added to the MPM list. In some embodiments, one (eg, only one) of the modes created via the DIMD may be added to the MPM list.

[0141] The device may determine that an intra-coding mode derivation process is enabled for a coding block (e.g., for use in MPM list generation). In this case, a second MPM list generation process (e.g., different from the MPM list generation process used when the intra-coding mode derivation process is disabled) may be determined / selected based on the intra-coding mode derivation process being enabled for that coding block. The second MPM list generation process may be used to generate an MPM list for the coding block when the intra-coding mode derivation process is enabled. The coding block may be decoded based on (e.g., using) the MPM list generated using the second MPM list generation process.

[0142] For example, the second MPM list generation process may involve using a TIMD for MPM list generation (e.g., based on the first intra-coding mode derivation process being enabled for the coding block). In an embodiment, the MPM list may be generated based on candidate intra-prediction modes derived via the TIMD. For example, the MPM generation process may involve testing multiple candidate intra-prediction modes for reconstructed pixels neighboring the coding block and selecting a candidate intra-prediction mode from the multiple candidate intra-prediction modes (e.g., based on the testing). The selected candidate intra-prediction mode may be added to the MPM list.

[0143] 7 shows an example of including two modes generated from TIMD in the MPM list. As shown in FIG. 7, including two TIMD generation modes (eg, candidate intra-prediction modes) may be similar to DIMD.

[0144] In an embodiment, the TIMD may be used to generate a primary MPM list. For example, the derived candidate intra-prediction mode may be added to a primary MPM list, e.g., one of the MPM lists. The TIMD may generate two intra-prediction modes and perform blending to combine the two modes. For example, the TIMD may result in the generation of two modes M1 and M2. The modes M1 and M2 may be included in the primary MPM list.

[0145] A redundancy check may be performed before a candidate mode is added to the MPM list (e.g., to avoid redundant modes). For example, whether to add a selected candidate intra-prediction mode to the MPM list may be determined based on comparing the selected candidate intra-prediction mode with a prediction mode on the MPM list. If a derived candidate intra-prediction mode (e.g., a selected candidate intra-prediction mode) is the same as a prediction mode on the MPM list, the video processing device may refrain from adding the derived candidate prediction mode to the MPM list. In an embodiment, if the primary MPM list already comprises M1 and / or M2, these modes may be excluded from the primary MPM list.

[0146] In an embodiment, the TIMD may be used to generate an intra-prediction mode (e.g., only a single intra-prediction mode). In such a case, the first mode (e.g., only the first mode) may be considered for MPM list generation.

[0147] In an embodiment, the first mode derived via the TIMD and the first mode derived via the DIMD may be used in MPM list generation. In an embodiment, the first mode derived via the TIMD (e.g., only the first mode derived via the TIMD) may be included in the MPM list. In such a case, the process of TIMD mode generation may be invoked in part to generate the first probable mode (e.g., instead of two modes).

[0148] The DIMD may derive two closely adjacent directional mode indices (eg, because a DIMD-derived directional mode index often participates in the search for its neighboring directional mode indexes and is added to the general list of the MPM).

[0149] In an embodiment, the first mode (eg, only the first mode) may be derived via the DIMD for MPM list generation (eg, instead of deriving two modes via the DIMD).

[0150] In an embodiment, the TIMD and DIMD may be used to generate a secondary MPM list. For example, the derived candidate intra-prediction modes may be added to the secondary MPM list. For example, the DIMD and TIMD modes may be included in the SMPM list. The secondary MPM list may be used less frequently (e.g., compared to the primary MPM list). Two modes (e.g., each of the two modes) obtained from the DIMD and two modes (e.g., each of the two modes) obtained from the TIMD may be included in the secondary MPM list (e.g., as described herein), or only a first mode (e.g., only a first mode obtained from the TIMD and / or DIMD, as described herein) may be included in the secondary MPM list.

[0151] Mutual exclusion of TIMD and DIMD in MPM list generation may be implemented. In an embodiment, either TIMD mode or DIMD mode may be included in the MPM list. A syntax element may indicate whether DIMD or TIMD is used for MPM list generation. For example, a video decoding device may receive a first indication that an intra-coding mode derivation process (e.g., TIMD) is enabled for a first coding block and / or a second indication that the intra-coding mode derivation process is disabled for a second coding block. The decoder may determine whether to perform DIMD or TIMD based on the indication. In an embodiment, DIMD may be performed to derive a candidate prediction mode. TIMD may be performed to derive a candidate prediction mode for the MPM list if a mode derived via DIMD is already included in the MPM list (e.g., generated from a default mode). In an embodiment, TIMD may not be performed (e.g., may be bypassed) when DIMD is performed to derive a candidate prediction mode and a DIMD candidate prediction mode is added to the MPM list. In an embodiment, TIMD may be performed to derive candidate prediction modes. If the mode derived via TIMD is already included in the MPM list, DIMD may be performed to derive candidate prediction modes for the MPM list. In an embodiment, TIMD may be performed to derive candidate prediction modes and DIMD may not be performed (e.g., may be bypassed) when TIMD is performed to derive candidate prediction modes and TIMD candidate prediction modes are added to the MPM list. In an embodiment, whether to perform DIMD or TIMD may be based on the coding mode of the block.

[0152] 8 illustrates an example MPM list for a TIMD and an example general MPM list. As illustrated, the MPM list for the TIMD may not include modes derived via a DIMD. In an embodiment, the general MPM list may include modes derived via a DIMD (e.g., DIMD modes) and modes derived via a TIMD (e.g., TIMD modes).

[0153] The MPM list may be used to infer a prediction mode (e.g., a best prediction mode) by using a template pixel. One or more modes from the MPM list may be tested against the template pixel, and one or more prediction modes (e.g., the best one or more prediction modes that minimize a prediction error) may be retained and considered as a TIMD mode. The MPM list generation may involve including a DIMD mode in the MPM list. For example, a DIMD process may be performed (e.g., at the decoder side) to derive a DIMD mode. The DIMD mode may be added to the MPM list (e.g., before performing a TIMD mode derivation process). In such a case, two consecutive processes of mode derivation may be performed (e.g., at the decoder side to decode one coding block).

[0154] In an embodiment, the MPM list generation process may involve deriving candidate intra-prediction modes but bypassing deriving candidate modes via DIMD (e.g., DIMD modes may be excluded or skipped from the MPM list used for the TIMD process). For example, when TIMD is used, DIMD derivation (e.g., deriving candidate modes via DIMD) may be bypassed in the MPM list generation. For example, based on a determination that TIMD is used for a coding block, an MPM list may be generated with DIMD modes excluded from the list. A decoder may refrain from invoking a DIMD process when generating an MPM list. In an embodiment, DIMD modes may be excluded from the MPM list when TIMD is used.

[0155] In an embodiment, one or more techniques described herein may be applied to a combined intra-inter prediction (CIIP) mode. The MPM generation process for a coding block may be determined (e.g., selected from different MPM generation processes) based on whether the prediction mode used for the coding block is a CIIP mode. The CIIP mode may combine inter prediction and intra prediction. In some example CIIP modes, the inter prediction mode may be obtained based on inter template matching and / or the intra prediction mode may be obtained based on TIMD. Intra prediction (e.g., generated using TIMD) may use an MPM mode, including a DIMD mode.

[0156] Whether the intra-coding mode derivation process is enabled may depend on whether a prediction mode used for a coding block is a CIIP mode. For example, the video decoding device and / or the video encoding device may determine that the intra-coding mode derivation process is enabled when a prediction mode used for a coding block is a CIIP mode. Based on the prediction mode for the coding block being a CIIP mode, a first MPM generation process (e.g., a process that may skip (e.g., bypass) performing DIMD) may be used. Based on the CIIP mode not being used for the coding block, a second MPM generation process (e.g., a process that may invoke DIMD) may be used.

[0157] Whether to skip (e.g., bypass) performing DIMD may be determined based on the coding mode. For example, when a certain coding mode (e.g., CIIP mode) is used, performing DIMD for the current coding block may be skipped (e.g., bypassed). DIMD mode may be excluded from the MPM list, for example, when the current prediction mode (e.g., the prediction mode for the current block) is CIIP. Excluding DIMD mode (or bypassing DIMD) when CIIP is used may result in the derivation of two modes (e.g., instead of the derivation of three modes). For example, not all three of inter-template matching, DIMD, and TIMD are processed (e.g., must be processed) for a coding block.

[0158] The TIMD process can be used to add MIP or machine learning (ML) based modes to the MPM list. In TIMD, potential candidates can be tested using templates on the block and correlating already decoded samples with predicted samples with a particular mode.

[0159] In an embodiment, MIP and / or ML based modes may be tested using TIMD modes. For example, an up and / or left shifted template of the current coding block may be used as a reference sample in TIMD. The reference sample may be used to predict one or more lines adjacent to the current block. The correlation between the reference sample and the current sample may be measured to evaluate whether the MIP and / or ML based modes may be added (e.g., included) in the MPM list.

[0160] Although the features and elements are described above 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. 1. A video decoding method, comprising: determining that an intra-coding mode derivation process is enabled for a first coding block; generating a first most probable mode (MPM) list for the first coding block based on a first MPM list generation process based on the intra-coding mode derivation process being enabled for the first coding block; decoding the first coding block based on the first MPM list; and determining that the intra-coding mode derivation process is disabled for a second coding block; generating a second MPM list for the second coding block based on a second MPM list generation process different from the first MPM list generation process based on the intra-coding mode derivation process being disabled for the second coding block; and decoding the second coding block based on the second MPM list.

2. The first MPM list generation process includes: Deriving a plurality of candidate intra-prediction modes, where deriving the candidate modes via decoder-side intra-mode derivation (DIMD) is bypassed; and and adding the plurality of candidate intra-prediction modes to the first MPM list.

3. The second MPM list generation process includes: deriving a plurality of candidate intra-prediction modes based on intra-prediction modes associated with neighboring blocks of the second coding block; deriving decoder-side intra-mode derivation (DIMD) candidates for the second coding block based on a histogram of gradients associated with reconstructed pixels neighboring the second coding block; and adding the plurality of candidate intra-prediction modes and the DIMD candidate to the second MPM list for the second coding block.

4. The first MPM list generation process includes: testing a plurality of candidate intra-prediction modes for reconstructed pixels neighboring the first coding block; selecting a candidate intra-prediction mode from the plurality of candidate intra-prediction modes based on said testing; and and adding the selected candidate intra-prediction mode to the first MPM list.

5. The first MPM list generation process includes: testing a plurality of candidate intra-prediction modes for reconstructed pixels neighboring the first coding block; selecting a candidate intra-prediction mode from the plurality of candidate intra-prediction modes based on said testing; and adding the selected candidate intra-prediction mode to the first MPM list; and deriving decoder-side intra-mode derivation (DIMD) candidates for the first coding block based on a histogram of gradients associated with reconstructed pixels neighboring the first coding block. and adding the DIMD candidate to the first MPM list for the first coding block.

6. The decoding of the first coding block is further based on the intra-coding mode derivation process, the intra-coding mode derivation process comprising: testing a plurality of candidate intra-prediction modes in the first MPM list for reconstructed pixels neighboring the first coding block; and selecting a candidate intra-prediction mode from the plurality of candidate intra-prediction modes based on the testing.

7. 2. The method of claim 1, further comprising: deriving a plurality of candidate intra-prediction modes for the second coding block based on a histogram of gradients associated with reconstructed pixels neighboring the second coding block, wherein generating the second MPM list for the second coding block is further based on the derived plurality of candidate intra-prediction modes.

8. generating the first MPM list for the first coding block, The method of claim 2 , further comprising adding a derived candidate intra-prediction mode of the plurality of candidate intra-prediction modes to a primary MPM list of the first MPM list.

9. generating the first MPM list for the first coding block, The method of claim 2 , further comprising adding the derived candidate intra-prediction mode of the plurality of candidate intra-prediction modes to a secondary MPM list of the first MPM list.

10. 5. The method of claim 4, further comprising: determining whether to add a selected one of the plurality of candidate intra prediction modes to the first MPM list by comparing the selected candidate intra prediction mode with a prediction mode on the first MPM list, and refraining from adding the selected candidate intra prediction mode to the first MPM list on the condition that the selected candidate intra prediction mode is the same as a prediction mode on the first MPM list.

11. receiving a first indication that the intra-coding mode derivation process is enabled for the first coding block, wherein determining that the intra-coding mode derivation process is enabled for the first coding block is based on the first indication; and 2. The method of claim 1 , further comprising: receiving a second indication that the intra-coding mode derivation process is disabled for the second coding block, wherein determining that the intra-coding mode derivation process is disabled for the second coding block is based on the second indication.

12. 2. The method of claim 1, wherein determining that the intra-coding mode derivation process is enabled for the first coding block is based on a combined intra-inter prediction (CIIP) mode being used for the first coding block.

13. A video decoding device configured to perform any one of the preceding claims.

14. 1. A video encoding method, comprising: determining that an intra-coding mode derivation process is enabled for a first coding block; generating a first most probable mode (MPM) list for the first coding block based on a first MPM list generation process based on the intra-coding mode derivation process being enabled for the first coding block; encoding the first coding block based on the first MPM list; determining that the intra-coding mode derivation process is disabled for a second coding block; generating a second MPM list for the second coding block based on a second MPM list generation process different from the first MPM list generation process based on the intra-coding mode derivation process being disabled for the second coding block; and encoding the second coding block based on the second MPM list.

15. The first MPM list generation process includes: Deriving a plurality of candidate intra-prediction modes, where deriving the candidate modes via decoder-side intra-mode derivation (DIMD) is bypassed; and and adding the plurality of candidate intra-prediction modes to the first MPM list.

16. The second MPM list generation process includes: deriving a plurality of candidate intra-prediction modes based on intra-prediction modes associated with neighboring blocks of the second coding block; deriving decoder-side intra-mode derivation (DIMD) candidates for the second coding block based on a histogram of gradients associated with reconstructed pixels neighboring the second coding block; and adding the plurality of candidate intra-prediction modes and the DIMD candidate to the second MPM list for the second coding block.

17. The first MPM list generation process includes: testing a plurality of candidate intra-prediction modes for reconstructed pixels neighboring the first coding block; selecting a candidate intra-prediction mode from the plurality of candidate intra-prediction modes based on said testing; and and adding the selected candidate intra-prediction mode to the first MPM list.

18. The first MPM list generation process includes: deriving decoder-side intra-mode derivation (DIMD) candidates for the first coding block based on a histogram of gradients associated with reconstructed pixels neighboring the first coding block; and adding the DIMD candidate to the first MPM list for the first coding block.

19. The encoding of the first coding block is further based on the intra-coding mode derivation process, the intra-coding mode derivation process comprising: testing a plurality of candidate intra-prediction modes in the first MPM list for reconstructed pixels neighboring the first coding block; and selecting a candidate intra-prediction mode from the plurality of candidate intra-prediction modes based on the testing.

20. 15. The method of claim 14, further comprising: deriving a plurality of candidate intra-prediction modes for the second coding block based on a histogram of gradients associated with reconstructed pixels neighboring the second coding block, wherein generating the second MPM list for the second coding block is further based on the derived plurality of candidate intra-prediction modes.

21. generating the first MPM list for the first coding block, 19. The method of claim 15, further comprising adding a derived candidate intra-prediction mode of the plurality of candidate intra-prediction modes to a primary MPM list of the first MPM list.

22. generating the first MPM list for the first coding block, 19. The method of claim 15, further comprising adding a derived candidate intra-prediction mode of the plurality of candidate intra-prediction modes to a secondary MPM list of the first MPM list.

23. 18. The method of claim 17, further comprising: determining whether to add a selected one of the plurality of candidate intra prediction modes to the first MPM list by comparing the selected candidate intra prediction mode with a prediction mode on the first MPM list, and refraining from adding the selected candidate intra prediction mode to the first MPM list on the condition that the selected candidate intra prediction mode is the same as a prediction mode on the first MPM list.

24. determining that the intra-coding mode derivation process is enabled for the first coding block; including a first indication in the video data that the intra-coding mode derivation process is enabled for the first coding block; determining to disable the intra-coding mode derivation process for the second coding block; The method of claim 14 , further comprising: including in the video data a second indication that the intra-coding mode derivation process is disabled for the second coding block.

25. 15. The method of claim 14, wherein determining that the intra-coding mode derivation process is enabled for the first coding block is based on a combined intra-inter prediction (CIIP) mode being used for the first coding block.

26. A video encoding device configured to perform any one of claims 14 to 25.

27. A computer program comprising program code instructions for implementing the steps of at least one of claims 1 to 12 or 14 to 25 when executed by a processor.

28. A computer program product, stored on a non-transitory computer readable medium and comprising program code instructions for implementing the steps of at least one of claims 1 to 12 or 14 to 25 when executed by a processor.

29. A bitstream comprising information representative of the first coding block and the second coding block encoded according to one of the methods of any one of claims 14 to 25.

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