pdpc with perspective intra prediction

Abstract

Video coding can use position dependent pixel combination (PDPC) for intra prediction with perspective. A prediction angle calculated at the third, sixth and twelfth pixels on the last row of a target block can be used to check angle scaling values of 0, 1 and 2, respectively. A non-negative scaling factor can indicate to apply normal PDPC, while a negative scaling factor can indicate to apply gradient PDPC. Anti-angles calculated at the first 3, 6 or 12 target pixels on each row corresponding to an angle scaling value of 0, 1 or 2, respectively, can be used to locate secondary reference samples for normal PDPC. An angle parameter at the secondary reference samples on the same row as the target pixels can be calculated / used to locate primary reference samples on a top reference array for gradient PDPC. A gradient between the reference samples can be used to modify an initial prediction value.

Description

[0001] Cross-references to related applications This application claims the benefit of European Patent Application No. 23306661.2, filed on 2 October 2023, the contents of which are incorporated herein by reference in their entirety. Background Technology

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

[0003] Systems, methods, and means for performing video coding by using position-dependent pixel combination (PDPC) for intra-frame prediction with perspective are disclosed. Predicted angles, which can be computed at the third, sixth, and twelfth pixels on the last row of the target block, can be used to examine angle scaling values ​​of 0, 1, and 2, respectively. In some examples, non-negative values ​​of the scaling factor can indicate the application of a first type of PDPC (e.g., normal or typical PDPC), while negative values ​​of the scaling factor can indicate the application of a second type of PDPC (e.g., gradient PDPC). In some examples (e.g., for the first type of PDPC), inverse angles, computed for example at the first 3, 6, or 12 target pixels on rows (e.g., each row) corresponding to angle scaling values ​​of 0, 1, or 2, can be used to locate secondary reference samples (e.g., for the first type of PDPC). In some examples (e.g., for the second type of PDPC), angle parameters at secondary reference samples on the same row as the target pixels can be computed and / or used to locate the primary reference sample on the top reference array. The gradient between the two reference samples can be used to modify the initial prediction value.

[0004] Video encoding devices (e.g., decoders or encoders) can implement methods for video encoding. A decoder or encoder can use a perspective intra-prediction mode to predict a target block, where the target block is predicted using perspective points. The decoder or encoder can apply a position-dependent pixel combination (PDPC) scheme to pixels associated with the perspective intra-prediction target block, where the PDPC scheme is applied based on a scaling parameter value. If the perspective intra-prediction mode is suitable for PDPC, the PDPC scheme can be applied. The PDPC scheme can be normal PDPC or gradient PDPC. When the scaling parameter value is greater than zero, the PDPC scheme can be normal PDPC. When the scaling parameter value is less than zero, the PDPC scheme can be gradient PDPC. Attached Figure Description

[0005] Figure 1AThis is a system diagram illustrating an example communication system in which one or more of the disclosed embodiments can be implemented.

[0006] Figure 1B The illustration shows that, according to the embodiment, it is possible to... Figure 1A The diagram shows a system diagram of an example wireless transmit / receive unit (WTRU) used in a communication system.

[0007] Figure 1C The illustration shows that, according to the embodiment, it is possible to... Figure 1A The diagram illustrates a system diagram of an example radio access network (RAN) and an example core network (CN) used within a communication system.

[0008] Figure 1D The illustration shows that, according to the embodiment, it is possible to... Figure 1A The diagram shows a further example RAN and a further example CN used in the communication system.

[0009] Figure 2 The illustration shows a sample video encoder.

[0010] Figure 3 The illustration shows an example video decoder.

[0011] Figure 4 The illustration shows an example of a system in which various aspects and examples can be implemented.

[0012] Figure 5 The illustration shows an example of a vertically related pixel combination (PDPC).

[0013] Figure 6 An example of a PDPC process in the positive vertical direction is illustrated.

[0014] Figure 7 An example of the gradient PDPC process in the positive vertical direction is illustrated.

[0015] Figure 8 The illustration shows an example of perspective prediction for a target block in intra-frame prediction.

[0016] Figure 9 An example of intra-frame prediction with perspective is illustrated.

[0017] Figure 10 An example of PDPC used for perspective prediction is illustrated.

[0018] Figure 11 An example of gradient PDPC used for perspective prediction is illustrated. Detailed Implementation

[0019] A more detailed understanding can be obtained from the following description, which is given by way of example in conjunction with the accompanying drawings.

[0020] Figure 1A This diagram illustrates an example communication system 100 in which one or more of the disclosed embodiments may be implemented. The communication system 100 may be a multiple access system providing content such as voice, data, video, messaging, and broadcasting to multiple wireless users. The communication system 100 enables multiple wireless users to access such content through the sharing of system resources, including wireless bandwidth. For example, the communication system 100 may employ one or more channel access methods, such as Code Division Multiple Access (CDMA), Time Division Multiple Access (TDMA), Frequency Division Multiple Access (FDMA), Orthogonal FDMA (OFDMA), Single Carrier FDMA (SC-FDMA), Zero-Tail Unique Word DFT Extended OFDM (ZT UW DTS-s OFDM), Unique Word OFDM (UW-OFDM), Resource Block Filtered OFDM, Filter Bank Multicarrier (FBMC), and the like.

[0021] like Figure 1A As shown, the communication system 100 may include wireless transmit / receive units (WTRUs) 102a, 102b, 102c, 102d, RAN 104 / 113, CN 106 / 115, Public Switched Telephone Network (PSTN) 108, Internet 110, and other networks 112. However, it will be understood that the disclosed embodiments contemplate any number of WTRUs, base stations, networks, and / or network elements. Each of the WTRUs 102a, 102b, 102c, and 102d can be any type of device configured to operate and / or communicate in a wireless environment. As an example, WTRUs 102a, 102b, 102c, and 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, pagers, cellular phones, personal digital assistants (PDAs), smartphones, laptops, netbooks, personal computers, wireless sensors, hotspots or Mi-Fi devices, Internet of Things (IoT) devices, watches or other wearable devices, head-mounted displays (HMDs), vehicles, drones, medical devices and applications (e.g., remote surgery), industrial devices and applications (e.g., robots and / or other wireless devices operating in the context of industrial and / or automated processing chains), consumer electronics devices, devices operating on commercial and / or industrial wireless networks, and the like. Any of WTRUs 102a, 102b, 102c, and 102d may be interchangeably referred to as a UE.

[0022] The communication system 100 may also include base station 114a and / or base station 114b. Each of base stations 114a and 114b can be any type of device configured to wirelessly interface with at least one of WTRUs 102a, 102b, 102c, and 102d to facilitate access to one or more communication networks, such as CN 106 / 115, Internet 110, and / or other networks 112. As an example, base stations 114a and 114b can be base transceiver stations (BTS), Node-B, eNode B, home node B, home eNode B, gNB, NR NodeB, site controllers, access points (APs), wireless routers, and the like. Although base stations 114a and 114b are each depicted as a single element, it will be understood that base stations 114a and 114b can include any number of interconnected base stations and / or network elements.

[0023] Base station 114a may be part of RAN 104 / 113, which may also include other base stations and / or network elements (not shown), such as base station controllers (BSCs), radio network controllers (RNCs), relay nodes, etc. Base station 114a and / or base station 114b may be configured to transmit and / or receive radio signals on one or more carrier frequencies (which may be referred to as cells (not shown)). These frequencies may be in licensed spectrum, unlicensed spectrum, or a combination of licensed and unlicensed spectrum. A cell may provide coverage of a specific geographic area, which may be relatively fixed or may change over time. A cell may be further divided into cell sectors. For example, the cell associated with base station 114a may be divided into three sectors. Thus, in one embodiment, base station 114a may include three transceivers, i.e., one transceiver per sector of the cell. In embodiments, base station 114a may employ multiple-input multiple-output (MIMO) technology and may utilize multiple transceivers for each sector of the cell. For example, beamforming may be used to transmit and / or receive signals in a desired spatial direction.

[0024] Base stations 114a and 114b can communicate with one or more of WTRUs 102a, 102b, 102c, and 102d via air interface 116, which can be any suitable wireless communication link (e.g., radio frequency (RF), microwave, centimeter wave, micrometer wave, infrared (IR), ultraviolet (UV), visible light, etc.). Any suitable radio access technology (RAT) can be used to establish air interface 116.

[0025] More specifically, as noted above, communication system 100 can be a multiple access system and can employ one or more channel access schemes, such as CDMA, TDMA, FDMA, OFDMA, SC-FDMA, and the like. For example, base stations 114a and WTRUs 102a, 102b, and 102c in RAN104 / 113 can implement radio technologies such as Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access (UTRA), which can use Wideband CDMA (WCDMA) to establish air interfaces 115 / 116 / 117. WCDMA can include communication protocols such as High-Speed ​​Packet Access (HSPA) and / or evolved HSPA (HSPA+). HSPA can include High-Speed ​​Downlink (DL) Packet Access (HSDPA) and / or High-Speed ​​UL Packet Access (HSUPA).

[0026] In the embodiment, base station 114a and WTRUs 102a, 102b, 102c can implement radio technologies such as evolved UMTS terrestrial radio access (E-UTRA), which can use Long Term Evolution (LTE) and / or Advanced LTE (LTE-A) and / or Advanced LTE Pro (LTE-A Pro) to establish air interface 116.

[0027] In the embodiment, base station 114a and WTRUs 102a, 102b, 102c can implement radio technology (such as NR radio access) that can use New Radio (NR) to establish air interface 116.

[0028] In the embodiments, base station 114a and WTRUs 102a, 102b, and 102c can implement various radio access technologies. For example, base station 114a and WTRUs 102a, 102b, and 102c can, for example, use a dual connectivity (DC) principle to implement both LTE and NR radio access together. Therefore, the air interface utilized by WTRUs 102a, 102b, and 102c can be characterized by various types of radio access technologies and / or transmissions sent to / from various types of base stations (e.g., eNBs and gNBs).

[0029] In other embodiments, base station 114a and WTRUs 102a, 102b, 102c can implement radio technologies such as IEEE 802.11 (i.e., Wi-Fi), IEEE 802.16 (i.e., Global Microwave Access Interoperability (WiMAX)), CDMA2000, CDMA2000 1X, CDMA2000 EV-DO, Provisional Standard 2000 (IS-2000), Provisional Standard 95 (IS-95), Provisional Standard 856 (IS-856), Global System for Mobile Communications (GSM), Enhanced Data Rate GSM Evolution (EDGE), GSM EDGE (GERAN), and the like.

[0030] Figure 1A Base station 114b can be, for example, a wireless router, home node B, home eNode B, or access point, and can utilize any suitable RAT to facilitate wireless connectivity in local areas such as commercial locations, homes, vehicles, campuses, industrial facilities, air corridors (e.g., for drone use), roads, and the like. In one embodiment, base station 114b and WTRUs 102c, 102d can implement radio technologies such as IEEE 802.11 to establish a wireless local area network (WLAN). In another embodiment, base station 114b and WTRUs 102c, 102d can implement radio technologies such as IEEE 802.15 to establish a wireless personal area network (WPAN). In yet another embodiment, base station 114b and WTRUs 102c, 102d can utilize cellular-based RATs (e.g., WCDMA, CDMA2000, GSM, LTE, LTE-A, LTE-A Pro, NR, etc.) to establish picocells or femtocells. Figure 1A As shown, base station 114b can have a direct connection to Internet 110. Therefore, base station 114b does not need to access Internet 110 via CN 106 / 115.

[0031] RAN 104 / 113 can communicate with CN 106 / 115, which can be any type of network configured to provide voice, data, application, and / or Voice over Internet Protocol (VoIP) services to one or more of WTRUs 102a, 102b, 102c, and 102d. Data can have different Quality of Service (QoS) requirements, such as different throughput requirements, latency requirements, error tolerance requirements, reliability requirements, data throughput requirements, mobility requirements, and the like. CN 106 / 115 can provide call control, billing services, location-based services, prepaid calling, internet connectivity, video distribution, and / or perform advanced security functions such as user authentication. Although not explicitly stated... Figure 1A As shown, but to be understood, RAN104 / 113 and / or CN 106 / 115 can communicate directly or indirectly with other RANs that use the same RAT as or a different RAT than RAN 104 / 113. For example, in addition to being connected to RAN 104 / 113, which can utilize NR radio technology, CN 106 / 115 can also communicate with another RAN (not shown) that uses GSM, UMTS, CDMA 2000, WiMAX, E-UTRA, or WiFi radio technology.

[0032] CN 106 / 115 can also be used as a gateway for WTRU 102a, 102b, 102c, 102d to access PSTN 108, the Internet 110, and / or other networks 112. PSTN 108 may include a circuit-switched telephone network providing Common Old-Style Telephone Service (POTS). The Internet 110 may include a global system of interconnected computer networks and devices using common communication protocols such as Transmission Control Protocol (TCP), User Datagram Protocol (UDP), and / or Internet Protocol (IP) from the TCP / IP Internet Protocol suite. Network 112 may include wired and / or wireless communication networks owned and / or operated by other service providers. For example, network 112 may include another CN connected to one or more RANs, which may use the same RAT as RAN 104 / 113 or a different RAT.

[0033] Some or all of the WTRUs 102a, 102b, 102c, and 102d in communication system 100 may include multi-mode capabilities (e.g., WTRUs 102a, 102b, 102c, and 102d may include multiple transceivers for communicating with different wireless networks via different wireless links). For example, Figure 1A The WTRU 102c shown can be configured to communicate with base station 114a, which can employ cellular-based radio technology, and with base station 114b, which can employ IEEE 802 radio technology.

[0034] Figure 1B This is a system diagram illustrating example WTRU 102. (Example:) Figure 1B As shown, among other things, WTRU 102 may also include a processor 118, a transceiver 120, a transmit / receive element 122, a speaker / microphone 124, a keypad 126, a display / touchpad 128, non-removable memory 130, removable memory 132, a power supply 134, a Global Positioning System (GPS) chipset 136, and / or other peripheral devices 138. It will be understood that, while remaining consistent with the embodiments, WTRU 102 may include any sub-combination of the foregoing elements.

[0035] 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, and the like. Processor 118 may perform signal encoding, data processing, power control, input / output processing, and / or any other functions that enable WTRU 102 to operate in a wireless environment. Processor 118 may be coupled to transceiver 120, and transceiver 120 may be coupled to transmit / receive element 122. Although Figure 1B The processor 118 and transceiver 120 are depicted as separate components, but it will be understood that the processor 118 and transceiver 120 may be integrated together in an electronic package or chip.

[0036] Transmitting / receiving element 122 can be configured to transmit signals to or receive signals from a base station (e.g., base station 114a) via air interface 116. For example, in one embodiment, transmitting / receiving element 122 can be an antenna configured to transmit and / or receive RF signals. In another embodiment, transmitting / receiving element 122 can be a transmitter / detector configured to transmit and / or receive, for example, IR, UV, or visible light signals. In yet another embodiment, transmitting / receiving element 122 can be configured to transmit and / or receive both RF signals and optical signals. It will be understood that transmitting / receiving element 122 can be configured to transmit and / or receive any combination of wireless signals.

[0037] Although the transmitting / receiving element 122 is in Figure 1B While depicted as a single element, WTRU 102 may include any number of transmit / receive elements 122. More specifically, WTRU 102 may employ MIMO technology. Thus, in one embodiment, WTRU 102 may include two or more transmit / receive elements 122 (e.g., multiple antennas) for transmitting and receiving wireless signals via air interface 116.

[0038] Transceiver 120 can be configured to modulate signals to be transmitted by transmitting / receiving element 122 and demodulate signals received by transmitting / receiving element 122. As noted above, WTRU 102 can have multi-mode capability. Therefore, transceiver 120 can include multiple transceivers to enable WTRU 102 to communicate via various RATs, such as NR and IEEE 802.11.

[0039] The processor 118 of WTRU 102 can be coupled to a speaker / microphone 124, a keypad 126, and / or a display / touchpad 128 (e.g., a liquid crystal display (LCD) unit or an organic light-emitting diode (OLED) display unit) and can receive user input data from the speaker / microphone 124, keypad 126, and / or display / touchpad 128. The processor 118 can also output user data to the speaker / microphone 124, keypad 126, and / or display / touchpad 128. Furthermore, the processor 118 can access information from any type of suitable memory (such as non-removable memory 130 and / or removable memory 132) and store data in any type of suitable memory. Non-removable memory 130 may include random access memory (RAM), read-only memory (ROM), a hard disk, or any other type of memory storage device. Removable memory 132 may include a subscriber identity module (SIM) card, memory stick, secure digital storage (SD) card, and the like. In other embodiments, processor 118 may access memory information that is never physically located on WTRU 102 (such as on a server or home computer (not shown)) and store the data in that memory.

[0040] The processor 118 may receive power from the power supply 134 and may be configured to distribute and / or control power to other components in the WTRU 102. The power supply 134 may be any suitable device for powering the WTRU 102. For example, the power supply 134 may include one or more dry cell battery packs (e.g., nickel-cadmium (NiCd), nickel-zinc (NiZn), nickel metal hydride (NiMH), lithium-ion (Li-ion), etc.), solar cells, fuel cells, and the like.

[0041] The processor 118 may also be coupled to a GPS chipset 136, which may be configured to provide location information (e.g., longitude and latitude) about the current location of the WTRU 102. In addition to or instead of the information from the GPS chipset 136, the WTRU 102 may receive location information from base stations (e.g., base stations 114a, 114b) via air interface 116 and / or determine its location based on the timing of signals received from two or more nearby base stations. It will be understood that, while remaining consistent with the embodiments, the WTRU 102 may acquire location information using any suitable location determination method.

[0042] The processor 118 may be further coupled to other peripheral devices 138, which may include one or more software and / or hardware modules providing additional features, functions, and / or wired or wireless connectivity. For example, peripheral devices 138 may include accelerometers, electronic compasses, satellite transceivers, digital cameras (for photos and / or video), Universal Serial Bus (USB) ports, vibration devices, television transceivers, hands-free headsets, Bluetooth® modules, FM radio units, digital music players, media players, video game player modules, internet browsers, virtual reality and / or augmented reality (VR / AR) devices, activity trackers, and the like. Peripheral devices 138 may include one or more sensors, which may be one or more of the following: gyroscopes, accelerometers, Hall effect sensors, magnetometers, orientation sensors, proximity sensors, temperature sensors, time sensors; geolocation sensors; altimeters, light sensors, touch sensors, magnetometers, barometers, gesture sensors, biometric sensors, and / or humidity sensors.

[0043] WTRU 102 may include a full-duplex radio for which the transmission and reception of some or all signals (e.g., associated with specific subframes for both UL (e.g., for transmission) and downlink (e.g., for reception)) may be concurrent and / or simultaneous. The full-duplex radio may include an interference management unit for reducing and / or substantially eliminating self-interference through signal processing via hardware (e.g., a choke) or via a processor (e.g., a separate processor (not shown) or via processor 118). In an embodiment, WTRU 102 may include a half-duplex radio for which the transmission and reception of some or all signals (e.g., associated with specific subframes for UL (e.g., for transmission) or downlink (e.g., for reception)) may be concurrent and / or simultaneous.

[0044] Figure 1C The diagram illustrates a system diagram of RAN 104 and CN 106 according to an embodiment. As noted above, RAN 104 can communicate with WTRUs 102a, 102b, and 102c via air interface 116 using E-UTRA radio technology. RAN 104 can also communicate with CN 106.

[0045] RAN 104 may include eNode-Bs 160a, 160b, and 160c; however, it will be understood that RAN 104 may include any number of eNode-Bs while remaining consistent with the embodiments. Each of eNode-Bs 160a, 160b, and 160c may include one or more transceivers for communicating with WTRUs 102a, 102b, and 102c via air interface 116. In one embodiment, eNode-Bs 160a, 160b, and 160c may implement MIMO technology. Therefore, eNode-B 160a may, for example, use multiple antennas to transmit radio signals to and / or receive radio signals from WTRU 102a.

[0046] Each of the eNode-B 160a, 160b, and 160c can be associated with a specific cell (not shown) and can be configured to handle radio resource management decisions, handover decisions, user scheduling in the UL and / or DL, and the like. Figure 1C As shown, eNode-B 160a, 160b, and 160c can communicate with each other via the X2 interface.

[0047] Figure 1C The CN 106 shown may include a Mobility Management Entity (MME) 162, a Serving Gateway (SGW) 164, and a Packet Data Network (PDN) Gateway (or PGW) 166. While each of the foregoing elements is depicted as part of CN 106, it will be understood that any of these elements may be owned and / or operated by an entity other than a CN operator.

[0048] The MME 162 can connect to each of the eNode-Bs 162a, 162b, and 162c in RAN 104 via the S1 interface and can be used as a control node. For example, the MME 162 can be responsible for authenticating users of WTRUs 102a, 102b, and 102c, bearer activation / deactivation, selecting a specific serving gateway during the initial attachment of WTRUs 102a, 102b, and 102c, and the like. The MME 162 can provide control plane functions for handover between RAN 104 and other RANs (not shown) employing other radio technologies such as GSM and / or WCDMA.

[0049] The SGW 164 can connect to each of the eNode Bs 160a, 160b, and 160c in RAN 104 via the S1 interface. The SGW 164 can typically route and forward user data packets to / from WTRUs 102a, 102b, and 102c. The SGW 164 can perform other functions such as anchoring the user plane during inter-eNode B handover, triggering paging when DL data is available for WTRUs 102a, 102b, and 102c, managing and storing the context of WTRUs 102a, 102b, and 102c, and so on.

[0050] The SGW 164 can connect to the PGW 166, which can provide WTRU 102a, 102b, and 102c with access to packet-switched networks (such as Internet 110) to facilitate communication between WTRU 102a, 102b, 102c and IP-enabled devices.

[0051] CN 106 can facilitate communication with other networks. For example, CN 106 can provide WTRUs 102a, 102b, and 102c with access to a circuit-switched network (such as PSTN 108) to facilitate communication between WTRUs 102a, 102b, and 102c and traditional landline communication equipment. For example, CN 106 may include an IP gateway (e.g., an IP Multimedia Subsystem (IMS) server) that serves as an interface between CN 106 and PSTN 108, or can communicate with such an IP gateway. Additionally, CN 106 can provide WTRUs 102a, 102b, and 102c with access to other networks 112, which may include other wired and / or wireless networks owned and / or operated by other service providers.

[0052] Despite WTRU in Figure 1A-1D While described as a wireless terminal, in some representative embodiments such a terminal may (e.g., temporarily or permanently) use a wired communication interface with a communication network.

[0053] In a representative embodiment, the other network 112 may be a WLAN.

[0054] A WLAN in Infrastructure Basic Services Set (BSS) mode can have an access point (AP) for the BSS and one or more stations (STAs) associated with the AP. The AP can have access or an 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 outside the BSS destined for a STA can reach and be delivered to the STA via the AP. Traffic originating from a STA destined for a destination outside the BSS can be sent to the AP for delivery to the appropriate destination. Traffic between STAs within the BSS can be sent via the AP, for example, where a source STA can send traffic to the AP, and the AP can deliver the traffic to the destination STA. Traffic between STAs within the BSS can be considered and / or referred to as point-to-point traffic. Point-to-point traffic can be sent between source and destination STAs (e.g., directly between them) using Direct Link Establishment (DLS). In some representative embodiments, the DLS can use 802.11e DLS or 802.11z Tunneling DLS (TDLS). WLANs using the Standalone BSS (IBSS) mode can function without an access point (AP), and STAs within the IBSS or using the IBSS (e.g., all STAs) can communicate directly with each other. The IBSS communication mode may sometimes be referred to as an "ad-hoc" communication mode in this document.

[0055] When using 802.11ac infrastructure operating mode or a similar operating mode, the AP can transmit beacons on a fixed channel, such as the primary channel. The primary channel can be of fixed width (e.g., a 20 MHz wide bandwidth) or dynamically set via signaling. The primary channel can be the operating channel of the BSS and can be used by the STA to establish a connection with the AP. In some representative embodiments, such as in an 802.11 system, Carrier Sense Multiple Access (CSMA / CA) with collision avoidance can be implemented. For CSMA / CA, STAs including the AP (e.g., each STA) can listen on the primary channel. If the primary channel is listened to / detected and / or determined to be busy by a particular STA, that STA can back off. A single STA (e.g., only one station) can transmit in a given BSS at any given time.

[0056] High-throughput (HT) STAs can communicate using a 40 MHz wide channel, for example, by combining a primary 20 MHz channel with adjacent or non-adjacent 20 MHz channels to form a 40 MHz wide channel.

[0057] The Very High Throughput (VHT) STA can support channels with widths of 20 MHz, 40 MHz, 80 MHz, and / or 160 MHz. 40 MHz and / or 80 MHz channels can be formed by combining consecutive 20 MHz channels. A 160 MHz channel can be formed by combining eight consecutive 20 MHz channels, or by combining two non-consecutive 80 MHz channels (which can be referred to as an 80+80 configuration). For the 80+80 configuration, after channel coding, data can be divided into two streams by a segment parser. Inverse Fast Fourier Transform (IFFT) processing and time-domain processing are performed separately on each stream. The streams can be mapped onto two 80 MHz channels, and data can be transmitted via the transmitting STA. At the receiver of the receiving STA, the above operations for the 80+80 configuration can be reversed, and the combined data can be sent to the Media Access Control (MAC).

[0058] 802.11af and 802.11ah support sub-1 GHz operating modes. Compared to those used in 802.11n and 802.11ac, 802.11af and 802.11ah reduce channel operating bandwidth and carrier. 802.11af supports 5 MHz, 10 MHz, and 20 MHz bandwidths in the TV white space (TVWS) spectrum, and 802.11ah supports 1 MHz, 2 MHz, 4 MHz, 8 MHz, and 16 MHz bandwidths using non-TVWS spectrum. According to representative embodiments, 802.11ah can support instrument-type control / machine-type communication, such as MTC devices in macro coverage areas. MTC devices may have certain capabilities, such as limited capabilities, including supporting (e.g., only supporting) certain bandwidths and / or limited bandwidths. MTC devices may include batteries with a battery life exceeding a threshold (e.g., for maintaining very long battery life).

[0059] WLAN systems that can support multiple channels, as well as channel bandwidths such as 802.11n, 802.11ac, 802.11af, and 802.11ah, include channels that can be designated as primary channels. A primary channel can have a bandwidth equal to the maximum common operating bandwidth supported by all STAs in the BSS. The bandwidth of the primary channel can be set and / or limited by STAs operating in the BSS that support the minimum bandwidth operating mode. In the 802.11ah example, for STAs that support (e.g., only support) the 1MHz mode (e.g., MTC type devices), the primary channel can be 1 MHz wide, even if the AP and other STAs in the BSS support 2MHz, 4 MHz, 8 MHz, 16 MHz, and / or other channel bandwidth operating modes. Carrier Sense and / or Network Allocation Vector (NAV) settings can depend on the status of the primary channel. If the primary channel is busy, for example, because an STA (which only supports the 1 MHz operating mode) is transmitting to the AP, the entire available band can be considered busy even if most of the band remains idle and potentially available.

[0060] In the United States, the available frequency band for 802.11ah is from 902 MHz to 928 MHz. In South Korea, the available frequency band is from 917.5 MHz to 923.5 MHz. In Japan, the available frequency band is from 916.5 MHz to 927.5 MHz. Depending on the country code, the total bandwidth available for 802.11ah ranges from 6 MHz to 26 MHz.

[0061] Figure 1D The diagram illustrates a system diagram of RAN 113 and CN 115 according to an embodiment. As noted above, RAN 113 may employ NR radio technology to communicate with WTRUs 102a, 102b, and 102c via air interface 116. RAN 113 may also communicate with CN 115.

[0062] RAN 113 may include gNBs 180a, 180b, and 180c, but it will be understood that RAN 113 may include any number of gNBs while remaining consistent with the embodiments. Each gNB 180a, 180b, and 180c may include one or more transceivers for communicating with WTRUs 102a, 102b, and 102c via air interface 116. In one embodiment, gNBs 180a, 180b, and 180c may implement MIMO technology. For example, gNBs 180a and 180b may utilize beamforming to transmit signals to and / or receive signals from gNBs 180a, 180b, and 180c. Therefore, gNB 180a may, for example, use multiple antennas to transmit radio signals to and / or receive radio signals from WTRU 102a. In embodiments, gNBs 180a, 180b, and 180c can implement carrier aggregation technology. For example, gNB 180a can transmit multiple component carriers (not shown) to WTRU 102a. A subset of these component carriers can be on unlicensed spectrum, while the remaining component carriers can be on licensed spectrum. In embodiments, gNBs 180a, 180b, and 180c can implement cooperative multipoint (CoMP) technology. For example, WTRU 102a can receive cooperative transmissions from gNBs 180a and 180b (and / or gNB 180c).

[0063] WTRUs 102a, 102b, and 102c can communicate with gNBs 180a, 180b, and 180c using transmissions associated with a scalable numerology. For example, OFDM symbol spacing and / or OFDM subcarrier spacing can vary depending on different transmissions, different cells, and / or different portions of the radio transmission spectrum. WTRUs 102a, 102b, and 102c can communicate with gNBs 180a, 180b, and 180c using subframes or transmission time intervals (TTIs) of various or scalable lengths (e.g., containing different numbers of OFDM symbols and / or continuously varying absolute time lengths).

[0064] gNBs 180a, 180b, and 180c can be configured to communicate with WTRUs 102a, 102b, and 102c in standalone and / or non-standalone configurations. In standalone configuration, WTRUs 102a, 102b, and 102c can communicate with gNBs 180a, 180b, and 180c without accessing other RANs (e.g., eNode-Bs 160a, 160b, and 160c). In standalone configuration, WTRUs 102a, 102b, and 102c can use one or more of gNBs 180a, 180b, and 180c as mobility anchors. In standalone configuration, WTRUs 102a, 102b, and 102c can communicate with gNBs 180a, 180b, and 180c using signals in unlicensed frequency bands. In a non-standalone configuration, WTRUs 102a, 102b, and 102c can communicate with / be connected to gNBs 180a, 180b, and 180c, and also communicate with / be connected to another RAN (such as eNode-B 160a, 160b, and 160c). For example, WTRUs 102a, 102b, and 102c can implement DC principles to communicate substantially simultaneously with one or more gNBs 180a, 180b, and 180c and one or more eNode-Bs 160a, 160b, and 160c. In a non-standalone configuration, eNode-B 160a, 160b, and 160c can be used as mobility anchors for WTRU 102a, 102b, and 102c, and gNB180a, 180b, and 180c can provide additional coverage and / or throughput for serving WTRU 102a, 102b, and 102c.

[0065] Each of gNBs 180a, 180b, and 180c can be associated with a specific cell (not shown) and can be configured to handle radio resource management decisions, handover decisions, user scheduling in UL and / or DL, network slicing support, dual connectivity, interoperability between NR and E-UTRA, routing of user plane data to User Plane Functions (UPF) 184a and 184b, routing of control plane information to Access and Mobility Management Functions (AMF) 182a and 182b, and the like. Figure 1D As shown, gNB 180a, 180b, and 180c can communicate with each other via the Xn interface.

[0066] Figure 1DThe CN 115 shown may include at least one AMF 182a, 182b, at least one UPF 184a, 184b, at least one Session Management Function (SMF) 183a, 183b, and may include a Data Network (DN) 185a, 185b. While each of the foregoing elements is depicted as part of the CN 115, it will be understood that any one of these elements may be owned and / or operated by an entity other than a CN operator.

[0067] AMF 182a and 182b can connect to one or more of gNBs 180a, 180b, and 180c in RAN 113 via the N2 interface and can be used as control nodes. For example, AMF 182a and 182b can be responsible for authenticating users of WTRU 102a, 102b, and 102c, supporting network slicing (e.g., handling different PDU sessions with different requirements), selecting specific SMF183a and 183b, managing registration areas, terminating NAS signaling, mobility management, and the like. AMF 182a and 182b can use network slicing to customize CN support for WTRU 102a, 102b, and 102c based on the type of services utilized by WTRU 102a, 102b, and 102c. For example, different network slices can be established for different use cases, such as services that rely on Ultra-Reliable Low Latency (URLLC) access, services that rely on Enhanced Massive Mobile Broadband (eMBB) access, services for Machine Type Communication (MTC) access, and / or the like. AMF 162 can provide control plane functions for handover between RAN 113 and other RANs (not shown) employing other radio technologies, such as LTE, LTE-A, LTE-A Pro, and / or non-3GPP access technologies, such as WiFi.

[0068] SMFs 183a and 183b can connect to AMFs 182a and 182b in CN 115 via the N11 interface. SMFs 183a and 183b can also connect to UPFs 184a and 184b in CN 115 via the N4 interface. SMFs 183a and 183b can select and control UPFs 184a and 184b, and configure the routing of traffic passing through UPFs 184a and 184b. SMFs 183a and 183b can perform other functions such as managing and allocating UE IP addresses, managing PDU sessions, controlling policy enforcement and QoS, providing downlink data notifications, and so on. PDU session types can be IP-based, non-IP-based, Ethernet-based, and so on.

[0069] UPF 184a and 184b can be connected via an N3 interface to one or more gNBs 180a, 180b, and 180c in RAN 113. This N3 interface can provide WTRU 102a, 102b, and 102c with access to a packet-switched network (such as the Internet 110) to facilitate communication between WTRU 102a, 102b, 102c and IP-enabled devices. UPF 184 and 184b can perform other functions such as routing and forwarding packets, enforcing user plane policies, supporting multihomed PDU sessions, handling user plane QoS, buffering downlink packets, providing mobility anchoring, and so on.

[0070] CN 115 can facilitate communication with other networks. For example, CN 115 may include an IP gateway (e.g., an IP Multimedia Subsystem (IMS) server) that serves as an interface between CN 115 and PSTN 108, or may communicate with such an IP gateway. Additionally, CN 115 can provide WTRUs 102a, 102b, and 102c with access to other networks 112, which may include other wired and / or wireless networks owned and / or operated by other service providers. In one embodiment, WTRUs 102a, 102b, and 102c can be connected to local data networks (DNs) 185a and 185b via UPFs 184a and 184b through their N3 interfaces and the N6 interface between UPFs 184a and 184b and DNs 185a and 185b.

[0071] Given Figure 1A-1D as well as Figure 1A-1D The corresponding descriptions, and one or more of the functions described herein with reference to one or more of the following items, may be performed by one or more emulation devices (not shown): WTRU102a-d, base station 114a-b, eNode-B 160a-c, MME 162, SGW 164, PGW 166, gNB 180a-c, AMF 182a-b, UPF 184a-b, SMF 183a-b, DN 185a-b, and / or any other device(s) described herein. An emulation device may be one or more devices configured to emulate one or more of the functions described herein. For example, an emulation device may be used to test other devices and / or simulate network and / or WTRU functions.

[0072] Simulation devices can be designed to perform one or more tests on other devices in a laboratory environment and / or a carrier network environment. For example, one or more simulation devices can perform one or more or all functions while being fully or partially implemented and / or deployed as part of a wired and / or wireless communication network to test other devices within the communication network. One or more simulation devices can perform one or more or all functions while being temporarily implemented / deployed as part of a wired and / or wireless communication network. Simulation devices can be directly coupled to another device for testing purposes and / or can be used to perform tests via over-the-air wireless communication.

[0073] One or more emulation devices can perform one or more (including all) functions without being implemented / deployed as part of a wired and / or wireless communication network. For example, emulation devices can be used in test scenarios within test laboratories and / or non-deployed (e.g., testing) wired and / or wireless communication networks to perform testing of one or more components. One or more emulation devices can be test rigs. Direct RF coupling and / or wireless communication via RF circuitry (e.g., which may include one or more antennas) can be used by the emulation devices to transmit and / or receive data.

[0074] This application describes various aspects, including tools, features, examples, models, methods, etc. Many of these aspects are described in detail, and are generally described in a manner that may sound restrictive, at least to illustrate the individual characteristics. However, this is for the purpose of clarity and does not limit the application or scope of those aspects. In fact, all the different aspects can be combined and interchanged to provide further aspects. Furthermore, the aspects described can also be combined and interchanged with aspects described in earlier submissions.

[0075] The aspects described and considered in this application can be implemented in many different forms. Figure 5-11 Some examples can be provided, but other examples are also welcome. Figure 5-11 The discussion does not limit the breadth of implementation. At least one of the aspects typically relates to video encoding and decoding, and at least one other aspect typically relates to the transmission of generated or encoded bitstreams. These and other aspects can be implemented as methods, apparatus, computer-readable storage media having instructions stored thereon for encoding or decoding video data according to any of the methods, and / or computer-readable storage media having a bitstream generated according to any of the methods stored thereon.

[0076] In this application, the terms “reconstruction” and “decoding” are used interchangeably, the terms “pixel” and “sample” are used interchangeably, and the terms “image”, “picture” and “frame” are used interchangeably.

[0077] Various methods are described herein, and each method includes one or more steps or actions for implementing the method. Unless the correct operation of the method requires a specific order of steps or actions, the order and / or use of specific steps and / or actions can be modified or combined. Furthermore, terms such as "first," "second," etc., may be used in various examples to modify elements, components, steps, operations, etc., such as, for example, "first decoding" and "second decoding." Unless specifically required, the use of such terms does not imply a sequence of modified operations. Therefore, in this example, the first decoding does not need to be performed before the second decoding and can occur, for example, before, during, or within a time period overlapping with the second decoding.

[0078] The various methods and other aspects described in this application can be used to modify the module, for example, such as Figure 2 and Figure 3 The decoding modules of the video encoder 200 and decoder 300 are shown herein. Furthermore, the subject matter disclosed herein can be applied to, for example, any type, format, or version of video encoding (whether described in standards or recommendations, whether pre-existing or future-developed) and any extensions to such standards and recommendations. Unless otherwise indicated or technically excluded, the aspects described in this application may be used individually or in combination.

[0079] Various numerical values ​​are used in the examples described in this application, such as target pixel positions (e.g., the third, sixth, and twelfth pixels in the last row of the target block), angular scaling values ​​of 0, 1, and 2, the first 3, 6, or 12 target pixels in each row corresponding to angular scaling values ​​of 0, 1, or 2, prediction patterns [19-49], y = -1, 0, 1, ..., (2*H-1), x = -1, 0, 1, ..., (2*W-1), reference sample coordinates, target block size (e.g., 4×4, 64×64, 32×4), weighting function wL value, constant, minimum, maximum, threshold, multiplier, divisor, exponent, resolution (e.g., 1 / 32, 1 / 64 of a pixel), range, etc. These and other specific values ​​are used for the purpose of describing the examples, and the aspects described are not limited to these specific values.

[0080] Figure 2 This is a diagram illustrating an example video encoder. Variations of the example encoder 200 are considered, but for clarity, encoder 200 is described below, without describing all anticipated variations.

[0081] Before being encoded, the video sequence may undergo pre-coding (201), for example, applying a color transform to the input color image (e.g., converting from RGB 4:4:4 to YCbCr 4:2:0), or performing remapping on the input image components to obtain a more compression-resistant signal distribution (e.g., using histogram equalization of one of the color components). Metadata may be associated with the pre-processing and attached to the bitstream.

[0082] In encoder 200, the image is encoded by encoder elements as described below. The image to be encoded is segmented (202) and processed in units, for example, coding units (CUs). For example, each unit is encoded using an intra-frame or inter-frame mode. When a unit is encoded in intra-frame mode, it performs intra-frame prediction (260). In inter-frame mode, motion estimation (275) and compensation (270) are performed. The encoder determines (205) which of the intra-frame or inter-frame modes to use for encoding the unit and indicates the intra-frame / inter-frame decision by, for example, a prediction mode flag. For example, the prediction residual is calculated by subtracting (210) the prediction block from the original image block.

[0083] The predicted residual is then transformed (225) and quantized (230). The quantized transform coefficients, along with the motion vector and other syntax elements (such as image segmentation information), are entropy encoded (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., directly encode the residual without applying either the transform or quantization process.

[0084] The encoder decodes the coded blocks to provide a reference for further prediction. The quantized transform coefficients are dequantized (240) and inverse transformed (250) to decode the prediction residuals. The image blocks are reconstructed by combining (255) the decoded prediction residuals and the prediction blocks. A loop filter (265) is applied to the reconstructed image to perform, for example, deblocking / SAO (Sample Adaptive Shift) / ALF (Adaptive Loop Filtering) filtering to reduce coding artifacts. The filtered image is stored in the reference image buffer (280).

[0085] Figure 3 This is a diagram illustrating an example video decoder. In the example decoder 300, the bitstream is decoded by decoder elements, as described below. The video decoder 300 typically performs operations similar to... Figure 2 The encoding process described herein is the reverse of the decoding process. Encoder 200 typically also performs video decoding as part of the encoding of video data.

[0086] Specifically, the input to the decoder includes a video bitstream, which can be generated by the video encoder 200. The bitstream is first entropy-decoded (330) to obtain transform coefficients, prediction modes, motion vectors, and other encoded information. Image segmentation information indicates how to segment the image. Therefore, the decoder can segment (335) the image based on the decoded image segmentation information. The transform coefficients are dequantized (340) and inverse transformed (350) to decode the prediction residuals. Image blocks are reconstructed by combining (355) the decoded prediction residuals and prediction blocks. Prediction blocks (370) can be obtained from intra-frame prediction (360) or motion-compensated prediction (i.e., inter-frame prediction) (375). A loop filter (365) is applied to the reconstructed image. The filtered image is stored at a reference image buffer (380). In some examples (e.g., for a given image), the contents of the reference image buffer 380 on the decoder 300 side can be the same as the contents of the reference image buffer 280 on the encoder 200 side (e.g., for the same image).

[0087] The decoded image can undergo further post-decoding processing (385), such as inverse color transformation (e.g., from YCbCr4:2:0 to RGB4:4:4) or inverse remapping of the remapping process performed in pre-encoding processing (201). Post-decoding processing can utilize metadata derived in pre-encoding processing and signaled in the bitstream. In the example, the decoded image (e.g., after applying a loop filter (365) and / or after post-decoding processing (385), if post-decoding processing is used) can be sent to a display device for rendering to the user.

[0088] Figure 4 This is a diagram illustrating an example of a system in which the various aspects and examples described herein can be implemented. System 400 can be implemented as a device including the various components described below and configured to perform one or more aspects of the various aspects described in this document. Examples of such devices include, but are not limited to, various electronic devices such as personal computers, laptop computers, smartphones, tablet computers, digital multimedia set-top boxes, digital television receivers, personal video recording systems, connected home appliances, and servers. The elements of system 400 can be implemented individually or in combination in a single integrated circuit (IC), multiple ICs, and / or discrete components. For example, in at least one example, the processing and encoder / decoder elements of system 400 are distributed across multiple ICs and / or discrete components. In various examples, system 400 is communicatively coupled to one or more other systems or other electronic devices via, for example, a communication bus or through dedicated input and / or output ports. In various examples, system 400 is configured to implement one or more aspects of the various aspects described in this document.

[0089] System 400 includes at least one processor 410 configured to execute instructions loaded therein for implementing various aspects, such as those described in this document. Processor 410 may include embedded memory, input / output interfaces, and various other circuitry as known in the art. System 400 includes at least one memory 420 (e.g., a volatile memory device and / or a non-volatile memory device). System 400 includes a storage device 440 that may include non-volatile memory and / or volatile memory, including but not limited to electrically erasable programmable read-only memory (EEPROM), read-only memory (ROM), programmable read-only memory (PROM), random access memory (RAM), dynamic random access memory (DRAM), static random access memory (SRAM), flash memory, disk drives, and / or optical disk drives. As a non-limiting example, storage device 440 may include internal storage devices, attached storage devices (including removable and non-removable storage devices), and / or network-accessible storage devices.

[0090] System 400 includes an encoder / decoder module 430 configured to, for example, process data to provide encoded or decoded video, and the encoder / decoder module 430 may include its own processor and memory. The encoder / decoder module 430 represents one or more modules that can be included in a device to perform encoding and / or decoding functions. It is well known that a device may include one or both encoding and decoding modules. Furthermore, the encoder / decoder module 430 may be implemented as a separate element of system 400, or it may be incorporated into processor 410 as a combination of hardware and software as known to those skilled in the art.

[0091] Program code to be loaded onto processor 410 or encoder / decoder 430 to execute the various aspects described in this document may be stored in storage device 440 and subsequently loaded onto memory 420 for execution by processor 410. According to various examples, one or more of processor 410, memory 420, storage device 440, and encoder / decoder module 430 may store one or more entries of various entries during the execution of the processes described in this document. Such stored entries 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 equations, formulas, operations, and operational logic.

[0092] In some examples, the internal memory of processor 410 and / or encoder / decoder module 430 is used to store instructions and provide working memory for processing during encoding or decoding. However, in other examples, external memory of the processing device (e.g., processor 410 or encoder / decoder module 430) is used for one or more of these functions. External memory can be memory 420 and / or storage device 440, such as volatile memory and / or non-volatile flash memory. In several examples, external non-volatile flash memory is used to store, for example, the operating system of a television. In at least one example, fast external volatile memory (such as RAM) is used as working memory for video encoding and decoding operations.

[0093] Inputs to the components of system 400 can be provided through various input devices as indicated in block 445. Such input devices include, but are not limited to: (i) a radio frequency (RF) section that receives, for example, RF signals transmitted over the air by a broadcaster; (ii) component (COMP) input terminals (or a set of COMP input terminals); (iii) universal serial bus (USB) input terminals; and / or (iv) high-definition multimedia interface (HDMI) input terminals. Figure 4 Other examples not shown include composite video.

[0094] In various examples, the input device of block 445 has associated corresponding input processing elements as known in the art. For example, the RF section may be associated with elements suitable for: (i) selecting a desired frequency (also known as selecting a signal, or limiting the signal band to a band), (ii) down-converting the selected signal, (iii) further band-limiting to a narrower band to select (e.g.,) a signal band that may be referred to as a channel in some examples, (iv) demodulating the down-converted and band-limited signal, (v) performing error correction, and / or (vi) demultiplexing to select the desired data packet stream. The RF section of various examples includes one or more elements for performing these functions, such as frequency selectors, signal selectors, band limiters, channel selectors, filters, downconverters, demodulators, error correctors, and demultiplexers. The RF section may include tuners that perform various functions among these functions, including, for example, down-converting the received signal to a lower frequency (e.g., intermediate frequency or near-baseband frequency) or down-converting it to baseband. In one set-top box example, the RF section and its associated input processing elements receive RF signals transmitted via a wired (e.g., cable) medium and perform frequency selection by filtering, down-converting, and re-filtering to the desired frequency band. Various examples rearrange the order of the components described above (and others), remove some of these components, and / or add other components that perform similar or different functions. Adding components may include inserting components between existing components, such as, for example, inserting amplifiers and analog-to-digital converters. In various examples, the RF section includes an antenna.

[0095] USB and / or HDMI terminals may include corresponding interface processors for connecting system 400 to other electronic devices across USB and / or HDMI connections. It should be understood that various aspects of input processing (e.g., Reed-Solomon error correction) may be implemented as needed, for example, within a separate input processing IC or within processor 410. Similarly, various aspects of USB or HDMI interface processing may be implemented as needed, either within a separate interface IC or within processor 410. Demodulation, error correction, and demultiplexing streams are provided to various processing elements, including, for example, processor 410 and encoder / decoder 430, which operate in conjunction with memory and storage elements to process the data streams as needed for presentation on an output device.

[0096] Various components of system 400 can be provided within an integrated housing in which various components can be interconnected and transmit data therebetween using a suitable connection arrangement 425 (e.g., internal buses as known in the art, including inter-IC (I2C) buses, wiring and printed circuit boards).

[0097] System 400 includes a communication interface 450 that enables communication with other devices via a communication channel 460. The communication interface 450 may include, but is not limited to, a transceiver configured to transmit and receive data via the communication channel 460. The communication interface 450 may include, but is not limited to, a modem or network interface card (NIC), and the communication channel 460 may be implemented, for example, within a wired and / or wireless medium.

[0098] In various examples, wireless networks, such as Wi-Fi networks (e.g., IEEE 802.11 (IEEE refers to the Institute of Electrical and Electronics Engineers)), are used to stream or otherwise provide data to system 400. In these examples, the Wi-Fi signal is received via a communication channel 460 and a communication interface 450 suitable for Wi-Fi communication. The communication channel 460 in these examples is typically connected to an access point or router that provides access to external networks, including the Internet, to allow streaming applications and other over-the-top communications. Other examples use a set-top box to provide streaming data to system 400, delivering data via an HDMI connection to input block 445. Still other examples use an RF connection to input block 445 to provide streaming data to system 400. As indicated above, various examples provide data in a non-streaming manner. Furthermore, various examples use wireless networks other than Wi-Fi, such as cellular networks or Bluetooth® networks.

[0099] System 400 can provide output signals to various output devices, including display 475, speaker 485, and other peripheral devices 495. Various examples of display 475 include one or more of, for example, touchscreen displays, organic light-emitting diode (OLED) displays, curved displays, and / or foldable displays. Display 475 can be used in televisions, tablet computers, laptop computers, cellular phones (mobile phones), or other devices. Display 475 can also be integrated with other components (e.g., as in a smartphone) or separate (e.g., an external monitor for a laptop computer). In various examples, other peripheral devices 495 include one or more of stand-alone digital video discs (or digital universal discs) (DVDs, for both terms), disk players, stereo systems, and / or lighting systems. Various examples use one or more peripheral devices 495 that provide functionality based on the output of system 400. For example, a disk player performs the function of playing the output of system 400.

[0100] In various examples, signaling (such as AV.Link, Consumer Electronics Control (CEC), or other communication protocols enabling device-to-device control with or without user intervention) is used to transmit control signals between system 400 and display 475, speaker 485, or other peripheral devices 495. Output devices can be communicatively coupled to system 400 via dedicated connections through corresponding interfaces 470, 480, and 490. Alternatively, output devices can be connected to system 400 via communication interface 450 using communication channel 460. In electronic devices (such as, for example, televisions), display 475 and speaker 485 can be integrated into a single unit with other components of system 400. In various examples, display interface 470 includes display drivers, such as, for example, a timing controller (TCon) chip.

[0101] For example, if the RF section of input 445 is part of a separate set-top box, then display 475 and speaker 485 can alternatively be separated from one or more other components. In various examples where display 475 and speaker 485 are external components, output signals can be provided via dedicated output connections, including, for example, HDMI ports, USB ports, or COMP outputs.

[0102] The example can be executed by computer software implemented via processor 410, or by hardware, or by a combination of hardware and software. As a non-limiting example, the example can be implemented by one or more integrated circuits. As a non-limiting example, memory 420 can be of any type suitable for the technical environment and can be implemented using any suitable data storage technology, such as optical storage devices, magnetic storage devices, semiconductor-based memory devices, fixed memory, and removable memory. As a non-limiting example, processor 410 can be of any type suitable for the technical environment and can encompass one or more of microprocessors, general-purpose computers, special-purpose computers, and processors based on multi-core architectures.

[0103] Various implementations involve decoding. As used herein, “decoding” can encompass all or part of a process performed, for example, on a received encoded sequence to produce a final output suitable for display. In various examples, such a process includes one or more processes typically performed by a decoder, such as entropy decoding, inverse quantization, inverse transform, and differential decoding. In various examples, such a process also includes, or alternatively includes, processes performed by a decoder of the various implementations described herein, such as predicting a target block using a perspective intra-prediction mode, where the target block is predicted using perspective points, applying a PDPC scheme to pixels associated with the perspective intra-prediction target block, where the PDPC scheme is applied based on scaling parameter values, etc.

[0104] As further examples, in one example, "decoding" refers only to entropy decoding; in another example, "decoding" refers only to differential decoding; and in yet another example, "decoding" refers to a combination of entropy decoding and differential decoding. Whether the phrase "decoding process" is intended to specifically refer to a subset of operations or generally to a broader decoding process will be clear based on the specific descriptive context and is considered well understood by those skilled in the art.

[0105] Various implementations involve encoding. In a manner similar to the discussion above regarding “decoding,” the term “encoding,” as used herein, can encompass all or part of a process performed, for example, on an input video sequence to produce an encoded bitstream. In various examples, such a process includes one or more processes typically performed by an encoder, such as segmentation, differential coding, transform, quantization, and entropy coding. In various examples, such a process also includes, or alternatively includes, processes performed by an encoder of the various implementations described herein, such as predicting a target block using a perspective intra-prediction mode, where the target block is predicted using perspective points, applying a PDPC scheme to pixels associated with the perspective intra-prediction target block, where the PDPC scheme is applied based on scaling parameter values, etc.

[0106] As further examples, in one example, "encoding" refers only to entropy encoding; in another example, "encoding" refers only to differential encoding; and in yet another example, "encoding" refers to a combination of differential and entropy encoding. Whether the phrase "encoding process" is intended to specifically refer to a subset of operations or generally to a broader encoding process will be clear based on the specific context of the description and is considered well understood by those skilled in the art.

[0107] Note that the syntax elements used in this paper, such as P(x,y) as the final predicted value, P_0(x,y) as the initial predicted value, R(-1,y) as the secondary reference sample, R(-1,-1) as the top-left reference sample, wL as the weighting function, R(-1,y') as the secondary reference sample obtained by extending the prediction direction, y' as the secondary reference sample, absInvAngle as the absolute value of the inverse angle associated with the prediction direction, A as the angle parameter associated with the prediction mode, R(x'',-1) as the predicted sample of the secondary reference sample R(-1,y), and A as the perspectiveAngle parameter (i.e., the angle parameter predIntraAngle). o The terms A(x,y), Lmax, numCol, maxScale, tmpScale, etc., which are angular parameters at the target pixel (x,y), are descriptive terms. Therefore, they do not preclude the use of other syntax element names.

[0108] When the accompanying drawings are presented as flowcharts, it should be understood that block diagrams of the corresponding devices are also provided. Similarly, when the accompanying drawings are presented as block diagrams, it should be understood that flowcharts of the corresponding methods / processes are also provided.

[0109] The implementations and aspects described herein can be implemented, for example, in a method or process, apparatus, software program, data stream, or signal. Even if discussed only in the context of a single form of implementation (e.g., discussed only as a method), the implementation of the discussed features can also be implemented in other forms (e.g., apparatus or program). Apparatus can be implemented, for example, in suitable hardware, software, and firmware. Methods can be implemented, for example, in a processor, which generally refers to a processing device, including, for example, a computer, microprocessor, integrated circuit, or programmable logic device. Processors also include communication devices, such as, for example, computers, cellular phones, portable / personal digital assistants (“PDAs”), and other devices that facilitate the transfer of information between end users.

[0110] References to “an example” or “an example” or “an implementation” or “an implementation” and their variations mean that the specific features, structures, characteristics, etc., described in connection with the example are included in at least one example. Therefore, the phrases “in an example” or “in the example” or “in an implementation” or “in the implementation” appearing throughout this application and any other variations do not necessarily refer to the same example.

[0111] Furthermore, this application may relate to "determining" fragments of various information. Determining information may include one or more of, for example, estimation information, calculation information, prediction information, or information retrieved from memory. Obtaining may include receiving, retrieving, constructing, generating, and / or determining.

[0112] Furthermore, this application may relate to “accessing” fragments of various information. Accessing information may include one or more of the following: receiving information, retrieving information (e.g., retrieving information from memory), storing information, moving information, copying information, calculating information, determining information, predicting information, or estimating information.

[0113] Furthermore, this application may relate to "receiving" fragments of various information. As with "access," receiving is intended to be a broad term. Receiving information may include one or more of, for example, accessing information or retrieving information (e.g., retrieving information from memory). Moreover, "receiving" is generally referred to in one or more ways during operations such as, for example, storing information, processing information, transmitting information, moving information, copying information, erasing information, calculating information, determining information, predicting information, or estimating information.

[0114] To be understood, for example, in the cases of “A / B,” “A and / or B,” and “at least one of A and B,” the use of any of the following “ / ,” “and / or,” and “at least one of…” is intended to cover selecting only the first listed option (A), or only the second listed option (B), or both options (A and B). As a further example, in the cases of “A, B, and / or C” and “at least one of A, B, and C,” such wording is intended to cover selecting only the first listed option (A), or only the second listed option (B), or only the third listed option (C), or only the first and second listed options (A and B), or only the first and third listed options (A and C), or only the second and third listed options (B and C), or all three options (A, B, and C). As will be clear to those skilled in the art and related fields, this can be extended to as many entries as possible listed.

[0115] Furthermore, among other things, as used herein, the term "signaling" also refers to instructing the corresponding decoder to do something. Encoder signals can include, for example, pdpcFlag, prediction modes, etc. Thus, in the example, the same parameters are used on both the encoder and decoder sides. Therefore, for example, the encoder can transmit (explicitly signal) a specific parameter to the decoder so that the decoder can use the same specific parameter. Conversely, if the decoder already has the specific parameter as well as other parameters, signaling can be used without transmission (implicitly signaling) to allow only the decoder to know and select the specific parameter. Bit savings are achieved in various examples by avoiding the transmission of any actual functionality. It is important to understand that signaling can be implemented in many ways. For example, in various examples, information is signaled to the corresponding decoder using one or more syntax elements, flags, etc. Although the verb form of the term "signaling" has been mentioned above, the word "signal" can also be used as a noun in this article.

[0116] As will be apparent to those skilled in the art, implementations can generate various signals that are formatted to carry, for example, information that can be stored or transmitted. The 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 bitstream of the described example. Such a signal may be formatted as, for example, electromagnetic waves (e.g., using the radio frequency portion of a spectrum) or as a baseband signal. Formatting may include, for example, encoding a data stream and modulating a carrier wave with the encoded data stream. The information carried by the signal may be, for example, analog or digital information. It is well known that signals can be transmitted via a variety of different wired or wireless links. Signals may be stored on, or accessed or received from, a processor-readable medium.

[0117] Numerous examples are described herein. Features of the examples may be provided individually or in any combination across various claim classes and types. Furthermore, examples may include one or more of the features, devices, or aspects described herein individually or in any combination across various claim classes and types. For example, features described herein may be implemented in a bitstream or signal including information generated as described herein. This information may allow a decoder to decode the bitstream, encoder, bitstream, and / or decoder according to any of the described examples. For example, features described herein may be implemented by creating and / or transmitting and / or receiving bitstreams or signals and / or decoding bitstreams or signals. For example, features described herein may be implemented by a method, process, apparatus, medium storing instructions, medium storing data, or signal. For example, features described herein may be implemented by a TV, set-top box, cellular phone, tablet computer, or other electronic device performing decoding. The TV, set-top box, cellular phone, tablet computer, or other electronic device may display (e.g., using a monitor, screen, or other type of display) an image obtained (e.g., an image reconstructed from a residual of a video bitstream). The TV, set-top box, cellular phone, tablet computer, or other electronic device may receive a signal including an encoded image and perform decoding.

[0118] Location-dependent pixel combination (PDPC) in certain video coding techniques can be a post-processing tool in intra-frame prediction. PDPC can be used to remove discontinuities, for example, discontinuities that may arise from the initial intra-frame prediction for a prediction pattern with a direction from the lower left corner of the block to the upper right corner, and vice versa. For example, different types of PDPC or PDPC schemes (e.g., normal PDPC or gradient PDPC) can be applied depending on the prediction direction and / or the target block size. For example, a prediction direction with (e.g., all required) available sub-reference samples may undergo normal PDPC, while a pattern with other suitable PDPCs may undergo gradient PDPC. This check can be performed, for example, by computing an angle scaling parameter involving the block size and an inverse angle parameter associated with the prediction direction. In some examples (e.g., intra-frame prediction with perspective), the prediction direction at the target pixel can be a variable quantity, meaning that the usual computation of the angle scaling parameter may not work. For example, the application of PDPC with a suitable prediction pattern in perspective intra-frame prediction can be determined based on the algorithms described herein.

[0119] As described herein, PDPC can be applied to intra-frame prediction with perspective. Predicted angles, which can be computed at the third, sixth, and twelfth pixels on the last row of the target block, can be used to examine angle scaling values ​​of 0, 1, and 2, respectively. In some examples, non-negative scaling factors can indicate the application of a first type of PDPC (e.g., normal or typical PDPC), while negative scaling factors can indicate the application of a second type of PDPC (e.g., gradient PDPC). In some examples (e.g., for first type PDPC), secondary reference samples can be located using, for example, inverse angles computed at the first 3, 6, or 12 target pixels on a row (e.g., each row) corresponding to angle scaling values ​​of 0, 1, or 2, respectively (e.g., for first type PDPC). In some examples (e.g., for second type PDPC), angle parameters at secondary reference samples on the same row as the target pixels can be computed and / or used to locate the primary reference sample on the top reference array. The gradient between the two reference samples can be used to modify the initial prediction.

[0120] PDPC can be used in intra-frame prediction to smooth out brightness discontinuities near the reference array that may occur after the initial prediction. For example, discontinuities may occur in planar modes, DC modes, and / or (e.g., all) directional prediction modes that may be associated with prediction directions below and / or including (e.g., purely) horizontal modes and / or to the right of vertical modes and / or including (e.g., purely) vertical modes. For example, PDPC may not be applicable to prediction modes associated with clockwise directions from (e.g., purely) horizontal to purely vertical (e.g., prediction modes in VVC and ECM [19-49]) because these prediction modes point to the lower right. In the case of directional modes, perspective prediction (e.g., as described herein) can be applied (e.g., only).

[0121] Figure 5 An example of a (e.g., purely) vertical PDPC is illustrated, which can be implemented in video coding techniques such as VVC and / or ECM. In the example, H and W can represent the height and width of the target block used for intra-frame prediction. The block is a reference array on the top that can have (2W+1) samples, while the reference array on the left can have (2H+1) samples, for example, where the samples in the top left corner are shared. The reference array in Figure 5 As shown in the diagram. Figure 5 As shown, R(-1,y), y= -1,0,1,…,(2*H-1) can represent the reference sample on the left, while R(x,-1), x= -1,0,1,…,(2*W-1) can represent the reference sample on the top, where R(-1,-1) serves as the reference sample in the upper left corner.

[0122] PDPC can be performed for (e.g., pure) vertical modes (e.g., mode 50 in VVC and / or ECM), for example, by increasing the weights of the gradients. For example, according to equation (1), the weights of the gradients can be computed as the initial prediction at the left reference pixel on the same row as the target pixel: For example, P(x,y) can be the final predicted value at pixel (x,y); P_0(x,y) can be the initial predicted value at pixel (x,y), which can be equal to the main reference sample R(x,-1); R(-1,y) can be the secondary reference sample on the same row; R(-1,-1) may be the upper left reference sample; and wL can be the weighting function. For example, the weighting function wL can be calculated according to equation (2): The scaling in equation (2) can be calculated, for example, according to equation (3): The scaling parameter can have positive integer values, for example, in the range of 0-2. For example, for a target block size of 4×4, the scaling parameter can have a value of zero (0), for a target block size of 64×64, the scaling parameter can have a value of two (2), and for all other block sizes between 4×4 and 64×64 (e.g., all), the scaling parameter can have a value in the range of 0-2. The scaling factor determines how quickly the weighted function wL decays to zero (0) as it moves to the right from the left edge of the block.

[0123] Table 1 shows an example of the number of columns. Beyond this number of columns, the weighting function wL may have a positive value for different scaling factor values. As shown in Table 1, the number of columns processed by PDPC can depend on the scaling value, which can depend on the target block size. For example, (e.g., only) 3 or 6 or 12 (e.g., ...). The column can be processed by PDPC in (e.g., pure) vertical mode. The original predicted value (P_0(x,y)) in equation (1) can remain unchanged for the remaining (e.g., unprocessed) columns, for example, where wL equals zero (0). For example, to avoid unnecessary multiplication by zero (0), the remaining columns may not be processed in PDPC.

[0124] Table 1 - Examples of columns or the number of columns processed in PDPC and their corresponding weights .

[0125] As we move from the left edge of the block to the right, the PDPC operation can add a gradually decaying weighted value of the gradient (e.g., calculated on the left reference array) to the initial prediction. For example, a pruning operation could be used because there is no guarantee that the resulting value will be within the dynamic range of the signal components.

[0126] For example, a weighting function (e.g., in VVC and / or ECM) can be chosen such that the weights, as shown in Table 1, are powers of two (2). The PDPC operation in equation (1) can therefore be performed using bit shifting, thus avoiding multiplication.

[0127] Predictions along (e.g., purely) horizontal directions (e.g., mode 18 in VVC and ECM) can be performed similarly using PDPC, except that rows are processed instead of columns at the top edges of the block. For example, scaling factors can be calculated in the same way (e.g., precisely). For example, the number of rows processed at the top can be given as ( The initial predictions in the remaining rows can remain unchanged. The weighted function values ​​can decay from top to bottom as you move along the columns. The gradient calculated on the top reference array can propagate downwards in a gradually decaying manner, for example, by adding to the initial predictions based on the left reference array.

[0128] Similarly, PDPC can be performed on predictions along the positive vertical direction (e.g., mode > 50 in VVC and ECM), for example, by changing the initial predictions. However, instead of adding the gradient weights to the initial predictions, a weighted sum with the sub-reference samples can be obtained. For example, as by Figure 6 As illustrated in the example, the secondary reference sample can be located by extending the prediction direction and finding the intersection with the secondary reference array on the left.

[0129] Figure 6 An example of a positive vertical (e.g., normal) PDPC process (e.g., in VVC and / or ECM) is illustrated. A secondary reference sample can be used to modify the first predicted value.

[0130] For example, a PDPC operation can be performed according to equation (4): Wherein, for example, P(x,y) can be the final predicted value at pixel (x,y); P_0(x,y) can be the initial predicted value at pixel (x,y), which can be equal to the main reference sample R(x',-1); R(-1,y') can be the secondary reference sample obtained by expanding the prediction direction; and wL can be the weighting function wL. For example, the weighting function wL can be calculated according to equation (5): For example, the coordinates of the secondary reference sample can be calculated according to equation (6): Where absInvAngle can represent the absolute value of the inverse angle associated with the prediction direction. The parameter absInvAngle can be derived, for example, from the angle parameter predIntraAngle associated with the prediction mode according to equations (7A) or (7B) as follows: absInvAngle=round((512*32) / A) (e.g., for a (1 / 32) sample resolution for the prediction direction) (7A) absInvAngle=round((512*64) / A) (e.g., for a (1 / 64) sample resolution for the prediction direction) (7B) Here, A can represent the angular parameter associated with the prediction pattern (e.g., A = predIntraAngle). In the example, since the final prediction is a weighted sum of the initial prediction and the secondary reference sample value, a pruning operation is not required.

[0131] When wL equals zero, the initial prediction can remain unchanged. The pruning operation can (e.g., only) in the first ( The process is performed on the columns, as is the case for PDPC in (e.g., a pure) vertical mode. Table 1, provided in this paper, shows examples of the number of columns processed and the weights of samples on different columns.

[0132] In some examples, although the weighting function in equation (5) can have the same form as equation (2), the scaling parameters can be calculated differently for equations (5) and (2) in PDPCs used for (e.g., pure) vertical modes. In some examples of PDPCs, the scaling parameters can be calculated using (e.g., only) the height and width of the target block as shown in equation (3) (e.g., again as shown in equation (8)): However, the formulas in equations (3) and (8) may have problems, for example, because the length of the reference array on the left is finite. For some prediction directions, even if the wL value is non-zero, there may not be enough samples on the left reference array to locate the first ( The sub-reference samples of the target pixels in the column (e.g., all). This problem can be avoided, for example, by calculating the scaling parameter according to equation (9) as follows: The example formula shown in equation (9) guarantees that the secondary reference sample can be used for the first ( The target pixels in the column (e.g., all). The formula in Equation (9) is based on the size of the block (e.g., more precisely, the height of the target block in vertical mode) and the prediction angle, while limiting the maximum number of columns to 12 (e.g., a maximum of 2 for scaling). Equation (9) can be derived, for example, by calculating the number of samples on the last row of the target block, which may have sub-reference samples available for a given prediction direction, and then calculating the scaling such that ( This will fit the length while limiting the maximum scaling value to two (2).

[0133] The scaling parameter calculated according to Equation (9) may have (e.g., only) three non-negative values ​​(e.g., 0, 1, and 2), which may correspond to the number of columns processed in the PDPC (e.g., 3, 6, and 12 columns), for example, with the corresponding weights given in Table 1. In contrast to the scaling parameter calculated according to Equation (3) or (8), for some angles, the scaling parameter calculated according to Equation (9) may (e.g., also) have negative integer values. Negative values ​​may mean that, for a given prediction pattern, even for the first three columns, there may not be enough secondary reference samples available. For a given prediction direction, the secondary reference array may be too short. For example, for directions close to (e.g., purely) vertical. In this case, a gradient PDPC operation may be performed, for example, instead of a normal PDPC. The gradient PDPC operation may be performed in a manner similar to that used for predictions utilizing (e.g., purely) vertical patterns, but the gradient may be computed along the considered prediction direction, as by Figure 7 The example is shown in the image.

[0134] Figure 7 An example of the gradient PDPC process in the positive vertical direction is illustrated (e.g., in VVC and ECM). The gradient weights can be computed at a sub-reference sample on the left-hand reference array in the same row as the target pixel. These gradient weights can be used to modify the initial prediction, for example, added to the initial prediction.

[0135] Gradient PDPC can, for example, modify the initial prediction value P_0(x,y) according to equation (10): Where, for example, P(x,y) can be the final predicted value at pixel (x,y); P_0(x,y) can be the initial predicted value at pixel (x,y), which can be equal to the main reference sample R(x',-1); R(-1,y) can be the secondary reference sample on the same row as the target pixel; R(x'',-1) can be the predicted value sample of the secondary reference sample R(-1,y); and wL can be, for example, a weighting function calculated according to equation (11): The scaling value in equation (11) can be calculated, for example, according to equation (12): The final calculated values ​​can be cropped to the dynamic range of the signal components, similar to the PDPC process in (e.g., pure) vertical mode. Table 1 shows examples of the number of columns processed and the corresponding weight values ​​for different scaling parameter values.

[0136] The type of PDPC applied to a given target block size can depend on the prediction mode. For example, gradient PDPC can be applied if / when the prediction direction becomes closer to the vertical direction. Normal PDPC can be applied otherwise. The type of PDPC can (e.g., similarly) depend on the block size given a suitable prediction direction. When the block size becomes smaller, for example, when there may not be enough sub-reference samples, gradient PDPC can replace normal PDPC. There may be specified or configurable relationships between the block size, prediction mode, and / or scaling parameters in the PDPC.

[0137] PDPC can be similarly performed for the positive horizontal direction (e.g., in VVC and / or ECM, 2 <= mode < 18, or mode < 0), except that rows are processed instead of columns at the top edges of the block. For example, normal PDPC or gradient PDPC can be applied depending on the value of the scaling parameter. For example, the scaling parameter can be calculated according to equation (13): For example, if the scaling is non-negative, normal PDPC can be applied to the top of the target block. If the scaling is negative, the scaling value can be recalculated. For example, the scaling can be recalculated according to equation (14): Gradient PDPC can be applied to the top of the target block ( The weights used for different rows (e.g., in either case) can be the same as those given in Table 1. The initial predictions in the remaining rows can remain unchanged.

[0138] For some blocks, the actual number of usable columns or rows may be less than ( For example, for a block of size 32×4, the scaling calculated according to the previous example could be equal to one (1), indicating that six (6) columns can be processed in vertical mode. However, the maximum number of columns for this block is four (4). Therefore (e.g., in VVC and / or ECM), the number of columns or rows processed by PDPC or gradient PDPC can be given as , where L = W or L = H, depending on whether the prediction direction is vertical or horizontal.

[0139] Figure 8 The illustration shows an example of perspective prediction for a target block in intra-frame prediction. Target pixels in a row or column can have different prediction orientations. Figure 8 In the example shown, the perspective point is located at the top of the block.

[0140] In intra-frame perspective prediction, perspective points can be used to predict target blocks, such as those derived from perspective points. Figure 8As illustrated in the example, a perspective point can be, for example, the intersection of a predicted direction (e.g., associated with the pattern) at the center of the target block and a straight line parallel to the side of the block at an offset distance. For a vertical prediction pattern, this line can be horizontal at an offset distance dy. For a horizontal pattern, this line can be vertical at an offset distance dx. The offset distances dx and dy can be referred to as the horizontal and vertical perspective distances, respectively. For a vertical angle pattern, the corresponding perspective prediction can be referred to as vertical. For a horizontal prediction, the corresponding perspective prediction can be referred to as horizontal. The examples described herein consider (e.g., only) perspective points on the top and left sides of the block, for example, because these are (e.g., only) cases that may result in intensity discontinuities at the left or top edges of the target block.

[0141] The difference between normal prediction and perspective-based prediction (e.g., the primary difference) is that, in the latter case, the prediction direction along a row or column can be variable. The angular parameter `predIntraAngle` (e.g., as defined in VVC and / or ECM) can be a function of the target pixel's position. The terms `perspectiveAngle` and `predIntraAngleArray(x,y)` can be used to distinguish between these two prediction types. The term `perspectiveAngle` can refer to the original `predIntraAngle`. The term `predIntraAngleArray(x,y)` can refer to the angular parameter at pixel position (x,y).

[0142] Figure 9 The illustration shows an example of intra-frame prediction with perspective. The predicted value of the target pixel can be a reference sample located in the direction connecting the target pixel and the perspective point. Figure 9 The angle parameters of the target pixel at position (x,y) were derived. Although Figure 9 The example illustration shows the vertical prediction mode, but for the horizontal mode, the situation might be similar when the perspective point is on the upper left of the block. Figure 9 As shown, let W and H represent the width and height of the target block, respectively. Let d represent the perspective height, which is the vertical distance from the perspective point to the top edge of the target block. For example, division can be avoided by assuming d is a power of 2. For vertical mode, d = k * H, where k = 2. n Let n = 0, 1, ..., Kmax. Kmax can be a preset integer. For the horizontal mode, d = k * W, where k = 2. n Let n = 0, 1, ..., Kmax. Let A(x, y) represent the value of predIntraAngleArray(x, y) at (x, y). o This represents the perspectiveAngle parameter, which can be the same as the angle parameter associated with the prediction pattern.

[0143] The angle parameter at the target pixel (x,y) can be calculated, for example, according to equation (15): Where A(x,0) can represent the angle parameter in the first row, but in the same column as the target pixel. A(x,0) can be calculated, for example, according to equation (16): Where s can be equal to, for example, five (5) or six (6), depending on whether the sample resolution for the prediction direction is 1 / 32 or 1 / 64 of pixels, respectively. For example, the value of predIntraAngleArray(x,y) can be computed as described in equation (15) or equation (16). The predicted value samples can be (e.g., then) identified and interpolated, for example, similar to identification and interpolation in VVC or ECM (e.g., the same).

[0144] PDPC can be implemented for intra-frame perspective prediction. For example, perspective prediction may be suitable for PDPC if the prediction direction at the left reference array (for vertical perspective prediction) or the top reference (for horizontal perspective prediction) is non-negative. For example, PDPC can be applied (e.g., after initial prediction) if the perspective point is on top of the block and to the right of the left reference line and includes the left reference line (for vertical perspective prediction), or on the left of the block and below the top reference line and includes the top reference line (for horizontal perspective prediction). The reference line can refer to a straight line passing through the corresponding reference array. For example, this condition can be expressed mathematically according to expression (17) or expression (18): Where A o It can be the perspectiveAngle value. The value of s can be equal to, for example, five (5) or six (6), depending on whether the sample resolution in the angular direction is 1 / 32 or 1 / 64 of the pixels, respectively. For example, if perspectiveAngle satisfies the conditions in expression (17) or expression (18), PDPC can be applied (e.g., after the initial perspective prediction).

[0145] Figure 10 An example of PDPC used for perspective prediction is illustrated. Figure 10 The illustration shows the PDPC applied in the case of vertical perspective prediction (e.g., normal PDPC). Figure 10 As shown, ( The initial predicted values ​​in the column can be modified, for example, according to equation (19): Where P(x,y) can be the final perspective prediction value at pixel (x,y), P_0(x,y) can be the initial perspective prediction value at pixel (x,y), which can be equal to the primary reference sample R(x',-1), R(-1,y') can be the secondary reference sample obtained by extending the prediction direction at pixel (x,y), and wL can be a weighting function, which can be calculated, for example, according to equation (20): For example, scaling parameters can be calculated so that the secondary reference sample can be used as the first ( ) of the target block. The target pixels in the column (e.g., all). A weighting function can be selected. In the example, the weighting function could be similar to that used in VVC and ECM to make PDPC with perspective prediction easier to adapt. In the example, the weighting function could be of a positive decreasing function type.

[0146] The position of the secondary reference sample R(-1,y') can be calculated, for example, according to equation (21): The value of absInvAngle can be calculated, for example, according to equation (22A): absInvAngle = round((512 * 32) / A(x,y)), for (1 / 32) sample resolution (22A) Or calculate according to equation (22B): absInvAngle = round((512 * 64) / A(x,y)), for (1 / 64) sample resolution (22B) The difference between the PDPC in normal intra-prediction and the PDPC in perspective intra-prediction is the localization of the secondary reference sample. In the PDPC with normal intra-prediction, angle parameters associated with the mode (e.g., A) can be used. o The reference sample is located using the angle parameter (e.g., A(x,y)) at the target pixel. In PDPC with perspective intra-prediction, the reference sample can be located using the angle parameter at the target pixel. PDPC with normal intra-prediction can be considered a special case of PDPC with perspective prediction, where for (e.g., all) target pixel locations (x,y), A(x,y) = A o .

[0147] For example, because the prediction angle in perspective prediction may depend on the coordinates of the target pixel, it can be calculated differently for each pixel with a corresponding angle parameter A. o The scaling parameter is calculated using the PDPC of absInvAngle. This paper provides an algorithm for calculating the scaling factor.

[0148] from Figure 8 It can be observed that the prediction angle becomes less positive as it moves to the right along the row, which can be expressed as follows: for (e.g., all) (x,y), A(x,y)>= A(x+1,y). From Figure 8 It can also be observed that moving the column down makes the predicted angles more irregular, which can be represented as follows: for (e.g., all) (x,y), A(x,y)>= A(x,y+1). These two observations may be valid for vertical perspective modes suitable for PDPC and / or horizontal perspective modes suitable for PDPC.

[0149] A PDPC denoted as W(x) with a general weighting function may have one or more of the following properties: (i) W(x) is positive and has values ​​in the range (0, 32); (ii) W(x) is non-increasing, for example, W(x) >= W(x+1); and / or (iii) W(x) = 0 for x >= Lmax. Lmax may be the maximum number of columns that can be processed by PDPC.

[0150] and Figure 8 Two related observations indicate, for example, that the availability of a secondary reference sample can be determined by examining the last row of the block starting from column Lmax. The availability of a secondary reference for any target pixel in the last row provides the availability of other pixels to its left (e.g., all). The availability of a secondary reference for any target pixel in the last row also provides the availability of secondary reference samples for target pixels in the rows above the last row (e.g., all), up to and including the columns that satisfy the check. When performing perspective prediction, the number of columns to which PDPC can be applied can be determined, for example, by the following logic or algorithm expressed as pseudocode: The weighting function can be viewed as being based on scaling parameters, for example, as indicated in equation (23): Similar to the aforementioned algorithm, the availability of the secondary reference sample can be checked first to obtain the maximum scaling value. If the sample is unavailable, the scaling value can be reduced (e.g., then). This process can be repeated until the scaling reaches zero (0). The following logic or algorithm, expressed as pseudocode, can implement this process: As indicated, the aforementioned algorithm sequentially checks whether the angle parameters and scaling values ​​at pixels 12, 6, and 3 on the last row of the block are greater than or equal to 2, 1, or 0, respectively. If the check is verified, PDPC can be performed. PDPC can be performed using the calculated scaling value (e.g., as explained herein). For example, if the scaling has a negative value, gradient PDPC can be applied (e.g., as described below).

[0151] Figure 11 An example of gradient PDPC for perspective prediction is illustrated. Gradient PDPC can be implemented (e.g., as described herein). For example, a sample of predicted values ​​for a secondary reference sample R(-1,y) can be computed using the prediction direction computed at (-1,y). Figure 11 As shown in the example, (for example, then) the gradient can be calculated. The initial perspective prediction can be modified, for example, according to equation (24): For example, P(x,y) can be the final perspective prediction value at pixel (x,y), P_0(x,y) can be the initial perspective prediction value at pixel (x,y), which can be equal to the primary reference sample R(x',-1), R(-1,y) can be the secondary reference sample on the same row as the target pixel, R(x'',-1) can be the perspective prediction value sample of the secondary reference sample R(-1,y), and wL can be a weighting function, which can be calculated, for example, according to equation (25): The scaling value in equation (25) can be calculated, for example, according to equation (26): PDPC or gradient PDPC can perform similar functions for horizontal perspective prediction, except that it processes rows instead of columns at the top edges of blocks. Position ( The scaling parameter of PDPC is calculated using the predicted angle on the last column of the block at ( ). For example, if the scaling value is positive, normal PDPC can be applied. For example, if the scaling value is not positive, gradient PDPC can be applied. The number of columns or rows processed by PDPC or gradient PDPC in perspective prediction (e.g., similar to PDPC with normal prediction and gradient PDPC) can be given as, for example , where L = W or L = H, depending on whether the prediction direction is vertical or horizontal.

[0152] This article describes various examples related to application scenarios of the PDPC algorithm with perspective intra-frame prediction. Video codecs can support intra-frame prediction with directional prediction modes.

[0153] In some examples, the encoder and decoder (e.g., codec) may support perspective intra-frame prediction, as described herein. Depending on the scaling parameter values, for example, if the perspective prediction mode is suitable for PDPC, a single PDPC (e.g., where gradient PDPC is disabled) or PDPC and gradient PDPC may be applied to the initial prediction at pixels in the target block.

[0154] In some examples, the encoder and decoder (e.g., codec) support perspective intra-frame prediction, as described herein. PDPC or gradient PDPC (e.g., as described herein) can be applied (e.g., optionally applied) to the initial prediction at pixels in the target block. This option can be implemented using a flag (e.g., pdpcFlag). For example, a value of one (1) of the flag can indicate the application of either PDPC or gradient PDPC, while a value of zero (0) can indicate that neither PDPC nor gradient PDPC is applied. This flag can be used (e.g., only) for modes suitable for PDPC.

[0155] In some examples, the encoder and decoder (e.g., codec) support perspective intra-prediction, as described herein. PDPC may not be applied after initial perspective intra-prediction. In the case of normal intra-prediction, PDPC or gradient PDPC may be applied. The encoder and decoder (e.g., codec) may (e.g., additionally and / or alternatively) support perspective intra-prediction, as described herein. The PDPC applied to perspective prediction can be similar to the PDPC applied to normal prediction.

[0156] In some examples, the secondary reference sample can be interpolated in PDPC with higher accuracy than nearest neighbor interpolation, or the predicted value of the secondary reference sample can be interpolated with higher accuracy than linear interpolation. For example, cubic interpolation can be performed whenever the predicted value of the secondary reference sample in PDPC or gradient PDPC is inconsistent with the reference sample.

[0157] In some examples, the application of PDPC or gradient PDPC can be deactivated if the left adjacent block (e.g., for vertical mode) or the top adjacent block (e.g., for horizontal mode) is not available.

[0158] PDPC for intra-frame prediction with perspective offers one or more advantages. The described PDPC algorithm can be used in conjunction with perspective intra-frame prediction. The prediction model can generate better predictions in sequences with perspective, which can lead to higher compression efficiency, for example, compared to using perspective prediction alone.

[0159] Although the features and elements have been described above in specific combinations, those skilled in the art will understand that each feature or element can be used alone or in combination with other features and elements. Furthermore, the methods described herein can be implemented in a computer program, software, or firmware incorporated into a computer-readable medium for execution by a computer or processor. Examples of computer-readable media include electronic signals (transmitted via 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-ROMs and Digital Universal Discs (DVDs)). The processor associated with the software can be used to implement a radio frequency transceiver for use in a WTRU, UE, terminal, base station, RNC, or any host computer.

Claims

1. An apparatus for video encoding, the apparatus comprising: The processor is configured to: The target block is predicted using a perspective intra-frame prediction mode, where the target block is predicted using perspective points; and The Position-Related Pixel Combination (PDPC) scheme is applied to pixels associated with target blocks predicted within the perspective frame, where the PDPC scheme is applied based on scaling parameter values.

2. The device according to claim 1, wherein, The processor is further configured to: Determine if the perspective intra-prediction mode is suitable for PDPC; and Based on the determination that the perspective intra-prediction mode is suitable for PDPC, the application of PDPC is determined.

3. The device according to claim 1 or 2, wherein, The PDPC scheme is either a normal PDPC scheme or a gradient PDPC scheme.

4. The device according to any one of claims 1 to 3, wherein, If the scaling parameter is greater than or equal to zero, the PDPC scheme is a normal PDPC, and if the scaling parameter value is less than zero, the PDPC scheme is a gradient PDPC.

5. The device according to any one of claims 1 to 4, wherein, The processor is further configured to: Obtain an indication indicating whether to apply the normal PDPC scheme or the gradient PDPC scheme.

6. The device according to any one of claims 1 to 5, wherein, The processor is further configured to: Determine whether the left adjacent block is available, wherein the PDPC scheme for the pixel is applied based on whether the left adjacent block is available.

7. The device according to any one of claims 1 to 6, wherein, The processor is further configured to: Determine whether the top adjacent block is available, wherein the PDPC scheme for the pixel is applied based on whether the top adjacent block is available.

8. The device for video encoding according to any one of claims 1 to 7, wherein, The device is a video decoder or video encoder.

9. A method for video encoding, the method comprising: The target block is predicted using a perspective intra-frame prediction mode, where the target block is predicted using perspective points; and The Position-Related Pixel Combination (PDPC) scheme is applied to pixels associated with target blocks predicted within the perspective frame, where the PDPC scheme is applied based on scaling parameter values.

10. The method according to claim 9, wherein, The method further includes: Determine if the perspective intra-prediction mode is suitable for PDPC; and Based on the determination that the perspective intra-prediction mode is suitable for PDPC, the application of PDPC is determined.

11. The method according to claim 9 or 10, wherein, The PDPC scheme is either a normal PDPC scheme or a gradient PDPC scheme.

12. The method according to any one of claims 9 to 11, wherein, If the scaling parameter is greater than or equal to zero, the PDPC scheme is a normal PDPC, and if the scaling parameter value is less than zero, the PDPC scheme is a gradient PDPC.

13. The method according to any one of claims 9 to 12, wherein, The method further includes: Obtain an indication indicating whether to apply the normal PDPC scheme or the gradient PDPC scheme.

14. The method according to any one of claims 9 to 13, wherein, The method further includes: Determine whether the left adjacent block is available, wherein the PDPC scheme for the pixel is applied based on whether the left adjacent block is available.

15. The method according to any one of claims 9 to 14, wherein, The method further includes: Determine whether the top adjacent block is available, wherein the PDPC scheme for the pixel is applied based on whether the top adjacent block is available.

16. The method according to any one of claims 9 to 15, wherein, The device is a video decoder or video encoder.

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