Method, apparatus and storage medium for video coding

Abstract

The application provides a method, device and storage medium for video decoding. The method for video decoding comprises determining one reference line from a plurality of reference lines for a current block in a picture; determining an intra prediction mode of the current block according to the one reference line determined from the plurality of reference lines; and performing intra prediction of the current block according to the determined intra prediction mode and one or more samples contained in the one reference line determined from the plurality of reference lines. The plurality of reference lines comprises one adjacent reference line and at least one non-adjacent reference line, wherein the adjacent reference line is adjacent to the current block, the at least one non-adjacent reference line is not adjacent to the current block, and for each non-adjacent reference line in the at least one non-adjacent reference line, a number of first intra prediction modes associated with the non-adjacent reference line is the same, and the number of first intra prediction modes of each non-adjacent reference line is less than a number of second intra prediction modes associated with the adjacent reference line.

Description

[0001] Cross-references

[0002] This disclosure claims priority to U.S. Provisional Application No. 62 / 629,519, filed on February 12, 2018, entitled “METHOD AND APPARATUS FOR MULTI-LINE INTRA PREDICTION IN VIDEO COMPRESSION,” and U.S. Application No. 16 / 200,128, filed on November 26, 2018, entitled “METHOD AND APPARATUS FOR MULTI-LINE INTRA PREDICTION IN VIDEO COMPRESSION,” the entire contents of which are incorporated herein by reference. Technical Field

[0003] The present application relates to the field of video encoding, and in particular to methods, devices, and storage media for video encoding and decoding. Background Art

[0004] The background description provided herein is intended to generally present the context of the present application. No admission is made, either explicitly or implicitly, that the work of the presently named inventors is prior art to the present invention insofar as it is described in this background section and insofar as it was not prior art at the time of filing.

[0005] Video encoding and decoding can be performed using inter-picture prediction with motion compensation. An uncompressed digital video may comprise a series of pictures, each picture having spatial dimensions of, for example, 1920×1080 luma samples and associated chroma samples. The series of pictures may have a fixed or variable picture rate (also informally referred to as a frame rate), for example, 60 pictures per second or 60 Hz. Uncompressed video has significant bitrate requirements. For example, 1080p60 4:2:0 video (1920x1080 luma sample resolution, 60 Hz frame rate) with 8 bits per sample requires a bandwidth of nearly 1.5 Gbit / s. One hour of such video would require over 600 gigabytes of storage space.

[0006] One goal of video encoding and decoding can be to reduce redundancy in the input video signal through compression. Compression can help reduce the bandwidth or storage space requirements mentioned above, in some cases by two orders of magnitude or more. Both lossless and lossy compression, as well as combinations of the two, can be used. Lossless compression refers to techniques that can reconstruct an exact replica of the original signal from the compressed original signal. When lossy compression is used, the reconstructed signal may not be identical to the original signal, but the distortion between the original and the reconstructed signal is small enough to make the reconstructed signal useful for the target application. Lossy compression is widely used for video. The amount of distortion that can be tolerated depends on the application; for example, users of certain consumer streaming applications may be able to tolerate higher distortion than users of television distribution applications. The achievable compression ratio can reflect this: higher allowed / tolerated distortion yields higher compression ratios.

[0007] Video encoders and decoders may utilize techniques from several broad categories, including, for example, motion compensation, transforms, quantization, and entropy coding.

[0008] Video coding techniques may include intra-frame coding techniques. In intra-frame coding, sample values ​​are represented without reference to samples or other data from a previously reconstructed reference picture. In some video codecs, a picture is spatially subdivided into sample blocks, and when all sample blocks are encoded using intra-frame mode, the picture can be an intra-frame picture. Intra-frame pictures and their derivatives, such as independent decoder refresh pictures, can be used to reset the state of the decoder and can therefore be used as the first picture in an encoded video stream and video session, or as a still image. The samples of the intra-frame block can be transformed, and the transform coefficients can be quantized before entropy coding. Intra-frame prediction is a technique for minimizing sample values ​​in the pre-transform domain. In some cases, the smaller the DC value after transformation and the smaller the AC coefficient, the fewer bits are required to represent the entropy-coded block with a specified quantization step size.

[0009] Traditional intra-frame coding, such as that known from, for example, MPEG-2 generation coding techniques, does not use intra-frame prediction. However, some newer video compression techniques include techniques that attempt to use, for example, surrounding sample data and / or metadata obtained during encoding / decoding of spatially adjacent, and preceding, data blocks in decoding order. Such techniques are hereinafter referred to as "intra-frame prediction" techniques. It should be noted that, at least in some cases, intra-frame prediction uses only reference data from the current image being reconstructed, rather than reference data from reference images.

[0010] Intra-frame prediction can take many different forms. When more than one such technique can be used for a given video coding technique, the technique being used can be encoded using the intra-frame prediction mode. In some cases, a mode can have sub-modes and / or parameters, and those can be encoded separately and / or included in the mode codeword. Which codeword is used for a given mode / sub-mode / parameter combination can affect the coding efficiency gains achieved with intra-frame prediction, and thus the entropy coding technique used to convert the codewords into the bitstream.

[0011] A certain mode of intra-frame prediction was introduced in H.264, refined in H.265, and further refined in newer coding technologies such as the Joint Exploitation Model (JEM), Next Generation Video Coding (VVC), and the Baseline Video Set (BMS). A prediction block can be formed using the values ​​of neighboring samples of available samples. Sample values ​​of neighboring samples are copied to the prediction block according to a certain direction. Reference to the direction used can be encoded in the bitstream or can itself be predicted.

[0012] As video coding technology has developed, the number of possible directions has increased. In H.264 (2003), 9 different directions were used. In H.265 (2013), the number of directions increased to 33, and JEM / VVC / BMS, when disclosed, can support up to 65 directions. Experiments have been conducted to identify the most likely directions, and certain techniques in entropy coding have been used to represent those possible directions with fewer bits, while for those less likely directions, some loss can be accepted. Furthermore, it is sometimes possible to predict the direction itself based on the adjacent directions of adjacent coded blocks.

[0013] The mapping of the intra-frame prediction direction bits representing directions in the encoded video stream can vary depending on the video coding technology; for example, it can be a simple direct mapping from prediction direction to intra-frame prediction mode or codeword, or it can be a complex adaptive strategy involving most probable mode and similar techniques. Those skilled in the art will be familiar with those techniques. However, in all cases, there may be some directions that are statistically less likely to appear in the video content than others. Since the goal of video compression is to reduce redundancy, in well-performing video coding technologies, those less likely directions will be represented by a larger number of bits than more likely directions.

[0014] In conventional intra prediction, the intra prediction process is limited to the lines (e.g., rows or columns) closest to the current block being predicted. However, other lines may also contain meaningful information for predicting the current block, thereby improving the prediction. Therefore, considering lines other than the closest line when performing intra prediction has significant advantages. Furthermore, reference samples with different line indices may have different characteristics. Therefore, setting the same number of intra prediction modes for different reference lines may not be optimal. Summary of the Invention

[0015] According to an embodiment disclosed in the present application, a method for video decoding is provided. The method includes determining a reference line for a current block in a picture from a plurality of reference lines, each reference line in the plurality of reference lines being parallel to a side of the current block; determining an intra-frame prediction mode for the current block based on the reference line determined from the plurality of reference lines; and performing intra-frame prediction of the current block based on the determined intra-frame prediction mode and one or more samples contained in the reference line determined from the plurality of reference lines; wherein the plurality of reference lines include adjacent reference lines and at least one non-adjacent reference line, wherein the adjacent reference lines are adjacent to the current block, the at least one non-adjacent reference line is not adjacent to the current block, and the number of intra-frame prediction modes associated with each of the at least one non-adjacent reference lines is equal to or less than half the number of intra-frame prediction modes associated with the adjacent reference lines.

[0016] According to an embodiment disclosed in the present application, a video decoder for video decoding is provided, comprising a processing circuit for determining a reference line for a current block in a picture from a plurality of reference lines, each reference line of the plurality of reference lines being parallel to a side of the current block; determining an intra-frame prediction mode of the current block based on the reference line determined from the plurality of reference lines; performing intra-frame prediction of the current block based on the determined intra-frame prediction mode and one or more samples contained in the reference line determined from the plurality of reference lines; wherein the plurality of reference lines include adjacent reference lines and at least one non-adjacent reference line, wherein the adjacent reference lines are adjacent to the current block, the at least one non-adjacent reference line is not adjacent to the current block, and the number of intra-frame prediction modes associated with each non-adjacent reference line of the at least one non-adjacent reference line is equal to or less than half of the number of intra-frame prediction modes associated with the adjacent reference lines. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Further features, properties and various advantages of the subject matter disclosed in this application will become more apparent from the following detailed description and accompanying drawings, in which:

[0018] Figure 1 A simplified block diagram of a communication system according to an embodiment of the present application is schematically shown;

[0019] Figure 2 A simplified block diagram of a communication system according to an embodiment of the present application is schematically shown;

[0020] Figure 3 A simplified block diagram of a decoder according to an embodiment of the present application is shown schematically;

[0021] Figure 4 A simplified block diagram of an encoder according to an embodiment of the present application is shown schematically;

[0022] Figure 5 A block diagram of an encoder according to another embodiment of the present application is shown;

[0023] Figure 6 A block diagram of a decoder according to another embodiment of the present application is shown;

[0024] Figure 7A and 7B Various angular modes of 35 prediction modes are shown;

[0025] Figure 8A and 8B Various angular modes of 67 prediction modes are shown;

[0026] Figure 9 is a schematic illustration of an exemplary intra-frame prediction mode;

[0027] Figure 10 is a schematic illustration of multi-line intra prediction according to an embodiment;

[0028] Figure 11 shows the process performed by an encoder or decoder of an embodiment;

[0029] Figure 12 It is a schematic illustration of a computer system according to an embodiment of the present application. DETAILED DESCRIPTION

[0030] Figure 1 The present invention schematically illustrates a simplified block diagram of a communication system (100) according to an embodiment of the present application. The communication system (100) includes a plurality of terminal devices, which can communicate with each other via, for example, a network (150). For example, the communication system (100) includes a terminal device (110) and a terminal device (120) interconnected via the network (150). Figure 1 In an embodiment, the terminal device (110) and the terminal device (120) perform unidirectional data transmission. For example, the terminal device (110) may encode video data (e.g., a video picture stream collected by the terminal device (110)) for transmission to another terminal device (120) via the network (150). The encoded video data is transmitted in the form of one or more encoded video streams. The terminal device (120) may receive the encoded video data from the network (150), decode the encoded video data to restore the video data, and display the video picture based on the restored video data. Unidirectional data transmission is more common in applications such as media services.

[0031] In another embodiment, a communication system (100) includes a terminal device (130) and a terminal device (140) that perform bidirectional transmission of encoded video data, which can occur, for example, during a video conference. For bidirectional data transmission, each of the terminal device (130) and the terminal device (140) can encode video data (e.g., a video picture stream collected by the terminal device) for transmission to the other terminal device (130) and the terminal device (140) via a network (150). Each of the terminal device (130) and the terminal device (140) can also receive the encoded video data transmitted by the other terminal device (130) and the terminal device (140), and can decode the encoded video data to restore the video data, and can display the video picture on an accessible display device based on the restored video data.

[0032] exist Figure 1In an embodiment of the present invention, the terminal device (110), the terminal device (120), the terminal device (130) and the terminal device (140) may be servers, personal computers and smart phones, but the principles disclosed in this application may not be limited thereto. The embodiments disclosed in this application are applicable to laptop computers, tablet computers, media players and / or dedicated video conferencing equipment. The network (150) represents any number of networks that transmit encoded video data between the terminal device (110), the terminal device (120), the terminal device (130) and the terminal device (140), including, for example, wired (wired) and / or wireless communication networks. The communication network (150) may exchange data in circuit switching and / or packet switching channels. The network may include a telecommunications network, a local area network, a wide area network and / or the Internet. For the purposes of this application, unless explained below, the architecture and topology of the network (150) may be irrelevant to the operations disclosed in this application.

[0033] As an example, Figure 2 The video encoder and video decoder are shown in a streaming environment. The subject matter disclosed in this application is equally applicable to other video-enabled applications, including, for example, video conferencing, digital TV, storing compressed video on digital media including CDs, DVDs, memory sticks, etc.

[0034] The streaming system may include an acquisition subsystem (213), which may include a video source (201) such as a digital camera, which creates an uncompressed video picture stream (202). In an embodiment, the video picture stream (202) includes samples captured by the digital camera. The video picture stream (202) is depicted as a thick line to emphasize the high data volume of the video picture stream compared to the encoded video data (204) (or encoded video code stream), and the video picture stream (202) can be processed by an electronic device (220), which includes a video encoder (203) coupled to the video source (201). The video encoder (203) may include hardware, software, or a combination of hardware and software to implement or implement various aspects of the disclosed subject matter as described in more detail below. Compared to the video picture stream (202), the encoded video data (204) (or the encoded video code stream (204)) is depicted as a thin line to emphasize the lower amount of data of the encoded video data (204) (or the encoded video code stream (204)), which can be stored on the streaming server (205) for future use. One or more streaming client subsystems, such as Figure 2The client subsystem (206) and the client subsystem (208) in the streaming server (205) can access the streaming server (205) to retrieve the copy (207) and the copy (209) of the encoded video data (204). The client subsystem (206) can include, for example, a video decoder (210) in the electronic device (230). The video decoder (210) decodes the incoming copy (207) of the encoded video data and produces an output video picture stream (211) that can be presented on a display (212) (e.g., a display screen) or another presentation device (not depicted). In some streaming systems, the encoded video data (204), the video data (207), and the video data (209) (e.g., a video bitstream) can be encoded according to certain video encoding / compression standards. Examples of such standards include ITU-T H.265. In an embodiment, the video coding standard under development is informally referred to as Versatile Video Coding (VVC), and the present application can be used in the context of the VVC standard.

[0035] It should be noted that the electronic device (220) and the electronic device (230) may include other components (not shown). For example, the electronic device (220) may include a video decoder (not shown), and the electronic device (230) may also include a video encoder (not shown).

[0036] Figure 3 The video decoder (310) is a block diagram of an embodiment of the present disclosure. The video decoder (310) may be provided in an electronic device (330). The electronic device (330) may include a receiver (331) (e.g., a receiving circuit). The video decoder (310) may be used to replace Figure 2 A video decoder (210) of an embodiment.

[0037] A receiver (331) may receive one or more encoded video sequences to be decoded by a video decoder (310); in the same or another embodiment, one encoded video sequence is received at a time, wherein each encoded video sequence is decoded independently of the other encoded video sequences. The encoded video sequence may be received from a channel (301), which may be a hardware / software link to a storage device storing the encoded video data. The receiver (331) may receive the encoded video data as well as other data, such as encoded audio data and / or auxiliary data streams, which may be forwarded to their respective consuming entities (not shown). The receiver (331) may separate the encoded video sequence from the other data. To prevent network jitter, a buffer memory (315) may be coupled between the receiver (331) and the entropy decoder / parser (320) (hereinafter referred to as "parser (320)"). In some applications, the buffer memory (315) is part of the video decoder (310). In other cases, the buffer memory (315) may be provided external to the video decoder (310) (not shown). In other cases, a buffer memory (not shown) is provided external to the video decoder (310) to, for example, mitigate network jitter, and another buffer memory (315) may be provided internally to the video decoder (310) to, for example, handle broadcast timing. Furthermore, when the receiver (331) receives data from a store / forward device with sufficient bandwidth and controllability or from an isochronous network, the buffer memory (315) may not be required, or the buffer memory may be smaller. Of course, for use on a traffic packet network such as the Internet, the buffer memory (315) may also be required. The buffer memory may be relatively large and have an adaptive size, and may be at least partially implemented in an operating system or similar component (not shown) external to the video decoder (310).

[0038] The video decoder (310) may include a parser (320) for reconstructing symbols (321) from the encoded video sequence. The types of symbols include information for managing the operation of the video decoder (310) and potential information for controlling a display device such as a display device (312) (e.g., a display screen) that is not part of the electronic device (330) but can be coupled to the electronic device (330), such as Figure 3As shown in . The control information for the display device may be a parameter set fragment (not shown) of Supplemental Enhancement Information (SEI message) or Video Usability Information (VUI). The parser (320) may parse / entropy decode the received coded video sequence. The coding of the coded video sequence may be performed according to a video coding technique or standard and may follow various principles, including variable length coding, Huffman coding, arithmetic coding with or without context sensitivity, and the like. The parser (320) may extract a subgroup parameter set for at least one subgroup of the subgroups of pixels in the video decoder from the coded video sequence based on at least one parameter corresponding to the group. The subgroup may include a Group of Pictures (GOP), a picture, a tile, a slice, a macroblock, a Coding Unit (CU), a block, a Transform Unit (TU), a Prediction Unit (PU), and the like. The parser (320) may also extract information from the encoded video sequence, such as transform coefficients, quantizer parameter values, motion vectors, and so on.

[0039] The parser (320) may perform entropy decoding / parsing operations on the video sequence received from the buffer memory (315), thereby creating symbols (321).

[0040] Depending on the type of coded video picture or portion of a coded video picture (e.g., inter- and intra-pictures, inter- and intra-blocks), and other factors, the reconstruction of the symbol (321) may involve a plurality of different units. Which units are involved and how they are involved may be controlled by subgroup control information parsed from the coded video sequence by the parser (320). For the sake of brevity, the flow of such subgroup control information between the parser (320) and the various units described below is not described.

[0041] In addition to the functional blocks already mentioned, the video decoder (310) can be conceptually broken down into several functional units as described below. In practical embodiments operating under commercial constraints, many of these units interact closely with each other and may be integrated with each other. However, for the purposes of describing the disclosed subject matter, the conceptual breakdown into the following functional units is appropriate.

[0042] The first unit is a scaler / inverse transform unit (351). The scaler / inverse transform unit (351) receives quantized transform coefficients as symbols (321) from the parser (320) along with control information, including which transform method to use, block size, quantization factor, quantization scaling matrix, etc. The scaler / inverse transform unit (351) may output a block comprising sample values, which may be input to an aggregator (355).

[0043] In some cases, the output samples of the scaler / inverse transform unit (351) may belong to an intra-coded block; that is, a block that does not use predictive information from a previously reconstructed picture, but may use predictive information from a previously reconstructed portion of the current picture. Such predictive information may be provided by the intra-picture prediction unit (352). In some cases, the intra-picture prediction unit (352) uses reconstructed information extracted from the current picture buffer (358) to generate surrounding blocks of the same size and shape as the block being reconstructed. For example, the current picture buffer (358) buffers partially reconstructed current pictures and / or fully reconstructed current pictures. In some cases, the aggregator (355) adds the prediction information generated by the intra-prediction unit (352) to the output sample information provided by the scaler / inverse transform unit (351) on a per-sample basis.

[0044] In other cases, the output samples of the scaler / inverse transform unit (351) may belong to inter-frame coded and potentially motion compensated blocks. In this case, the motion compensated prediction unit (353) may access the reference picture memory (357) to extract samples for prediction. After the extracted samples are motion compensated according to the symbols (321), these samples may be added to the output of the scaler / inverse transform unit (351) (in this case referred to as residual samples or residual signal) by the aggregator (355) to generate output sample information. The retrieval of the prediction samples by the motion compensated prediction unit (353) from the address in the reference picture memory (357) may be controlled by a motion vector, and the motion vector is provided to the motion compensated prediction unit (353) in the form of the symbols (321), for example, including X, Y and reference picture components. Motion compensation may also include interpolation of sample values ​​extracted from the reference picture memory (357) when using sub-sample accurate motion vectors, motion vector prediction mechanisms, etc.

[0045] The output samples of the aggregator (355) may be used by various loop filtering techniques in a loop filter unit (356). The video compression techniques may include in-loop filtering techniques that are controlled by parameters included in the coded video sequence (also referred to as the coded video bitstream) and made available to the loop filter unit (356) as symbols (321) from the parser (320). However, in other embodiments, the video compression techniques may also be responsive to meta-information obtained during decoding of a coded picture or a previous (in decoding order) portion of the coded video sequence, as well as to previously reconstructed and loop-filtered sample values.

[0046] The output of the loop filter unit (356) may be a sample stream that may be output to a display device (312) and stored in a reference picture memory (357) for subsequent inter-picture prediction.

[0047] Once fully reconstructed, certain coded pictures can be used as reference pictures for future prediction. For example, once the coded picture corresponding to the current picture is fully reconstructed and the coded picture is identified as a reference picture (e.g., by the parser (320)), the current picture buffer (358) can become part of the reference picture memory (357) and a new current picture buffer can be reallocated before starting to reconstruct a subsequent coded picture.

[0048] The video decoder (310) may perform decoding operations according to a predetermined video compression technique, such as that in the ITU-T H.265 standard. The encoded video sequence may conform to the syntax specified by the video compression technology or standard used in the sense that the encoded video sequence follows the syntax of the video compression technology or standard and the profile recorded in the video compression technology or standard. Specifically, the profile may select certain tools from all the tools available in the video compression technology or standard as the only tools available for use under the profile. For compliance, the complexity of the encoded video sequence is also required to be within the range defined by the hierarchy of the video compression technology or standard. In some cases, the hierarchy limits the maximum picture size, maximum frame rate, maximum reconstruction sampling rate (measured in, for example, megasamples per second), maximum reference picture size, etc. In some cases, the limits set by the hierarchy may be further defined by the Hypothetical Reference Decoder (HRD) specification and metadata of the HRD buffer management signaled in the encoded video sequence.

[0049] In an embodiment, a receiver (331) may receive additional (redundant) data along with the encoded video. The additional data may be part of the encoded video sequence. The additional data may be used by the video decoder (310) to properly decode the data and / or more accurately reconstruct the original video data. The additional data may be in the form of, for example, temporal, spatial, or signal-to-noise ratio (SNR) enhancement layers, redundant slices, redundant pictures, forward error correction codes, and the like.

[0050] Figure 4 1 is a block diagram of a video encoder (403) according to an embodiment disclosed in the present application. The video encoder (403) is provided in an electronic device (420). The electronic device (420) includes a transmitter (440) (e.g., a transmission circuit). The video encoder (403) can be used to replace Figure 2 A video encoder (203) in an embodiment.

[0051] The video encoder (403) can be used to generate a video from a video source (401) (not Figure 4 In another embodiment, the video source (401) is a part of the electronic device (420) to receive video samples, wherein the video source can capture video images to be encoded by the video encoder (403). In another embodiment, the video source (401) is a part of the electronic device (420).

[0052] The video source (401) may provide a source video sequence in the form of a stream of digital video samples to be encoded by the video encoder (403), wherein the stream of digital video samples may have any suitable bit depth (e.g., 8-bit, 10-bit, 12-bit, ...), any color space (e.g., BT.601 Y CrCB, RGB, ...), and any suitable sampling structure (e.g., Y CrCb 4:2:0, Y CrCb 4:4:4). In a media serving system, the video source (401) may be a storage device storing previously prepared videos. In a video conferencing system, the video source (401) may be a camera that captures local image information as a video sequence. The video data may be provided as a plurality of individual pictures that are given motion when viewed sequentially. The pictures themselves may be constructed as a spatial array of pixels, where each pixel may include one or more samples depending on the sampling structure, color space, etc. used. The relationship between pixels and samples can be readily understood by those skilled in the art. The following description focuses on samples.

[0053] According to an embodiment, the video encoder (403) may encode and compress pictures of a source video sequence into an encoded video sequence (443) in real time or under any other time constraints required by the application. Implementing an appropriate encoding speed is a function of the controller (450). In some embodiments, the controller (450) controls other functional units as described below and is functionally coupled to these units. For the sake of simplicity, the coupling is not shown in the figure. The parameters set by the controller (450) may include rate control related parameters (picture skipping, quantizer, lambda value of rate-distortion optimization technology, etc.), picture size, group of pictures (GOP) layout, maximum motion vector search range, etc. The controller (450) may be used to have other suitable functions that are related to the video encoder (403) optimized for a certain system design.

[0054] In some embodiments, the video encoder (403) operates in a coding loop. As a simplified description, in embodiments, the coding loop may include a source encoder (430) (e.g., responsible for creating symbols, such as a symbol stream, based on the input picture to be encoded and the reference picture) and a (local) decoder (433) embedded in the video encoder (403). The decoder (433) reconstructs the symbols to create sample data in a manner similar to how the (remote) decoder creates sample data (because in the video compression technology considered in this application, any compression between the symbols and the encoded video code stream is lossless). The reconstructed sample stream (sample data) is input to a reference picture memory (434). Since the decoding of the symbol stream produces bit-accurate results regardless of the decoder location (local or remote), the contents of the reference picture memory (434) are also bit-accurate between the local encoder and the remote encoder. In other words, the reference picture samples "seen" by the prediction part of the encoder are exactly the same as the sample values ​​that the decoder will "see" when using the prediction during decoding. This basic principle of reference picture synchronization (and the resulting drift when synchronization cannot be maintained, eg due to channel errors) is also used in some related techniques.

[0055] The operation of the "local" decoder (433) can be combined with the operation of Figure 3 The "remote" decoder of the video decoder (310) is described in detail. However, additional brief reference is made to Figure 3 , when symbols are available and the entropy encoder (445) and parser (320) are capable of losslessly encoding / decoding the symbols into an encoded video sequence, the entropy decoding portion of the video decoder (310), including the buffer memory (315) and the parser (320), may not be fully implemented in the local decoder (433).

[0056] At this point, it can be observed that any decoder technology other than parsing / entropy decoding present in the decoder must also be present in a substantially identical functional form in the corresponding encoder. For this reason, this application focuses on the decoder operation. The description of the encoder technology can be simplified because the encoder technology is mutually inverse to the decoder technology described comprehensively. A more detailed description is only required in certain areas and is provided below.

[0057] During operation, in some embodiments, the source encoder (430) may perform motion-compensated predictive coding. The motion-compensated predictive coding predictively encodes an input picture with reference to one or more previously encoded pictures in a video sequence designated as "reference pictures." In this manner, the encoding engine (432) encodes the differences between pixel blocks of the input picture and pixel blocks of a reference picture that may be selected as a prediction reference for the input picture.

[0058] The local video decoder (433) may decode the encoded video data of a picture that may be designated as a reference picture based on the symbols created by the source encoder (430). The operation of the encoding engine (432) may be a lossy process. When the encoded video data is available at the video decoder ( Figure 4 When decoded at a remote location (not shown), the reconstructed video sequence may typically be a copy of the source video sequence with some errors. The local video decoder (433) replicates the decoding process that the video decoder may perform on the reference picture and may cause the reconstructed reference picture to be stored in the reference picture cache (434). In this way, the video encoder (403) may locally store a copy of the reconstructed reference picture that has common content (absent transmission errors) with the reconstructed reference picture that will be obtained by the remote video decoder.

[0059] The predictor (435) may perform a prediction search for the encoding engine (432). That is, for a new picture to be encoded, the predictor (435) may search the reference picture memory (434) for sample data (as candidate reference pixel blocks) or certain metadata, such as reference picture motion vectors, block shapes, etc., that may serve as suitable prediction references for the new picture. The predictor (435) may operate on a pixel-by-pixel-block basis based on sample blocks to find a suitable prediction reference. In some cases, based on the search results obtained by the predictor (435), it may be determined that the input picture may have prediction references taken from multiple reference pictures stored in the reference picture memory (434).

[0060] The controller (450) may manage encoding operations of the source encoder (430), including, for example, setting parameters and subgroup parameters for encoding video data.

[0061] The outputs of all the above functional units may be entropy coded in an entropy encoder (445). The entropy encoder (445) losslessly compresses the symbols generated by the various functional units using techniques known to those skilled in the art, such as Huffman coding, variable length coding, arithmetic coding, etc., thereby converting the symbols into a coded video sequence.

[0062] The transmitter (440) can buffer the encoded video sequence created by the entropy encoder (445) in preparation for transmission over a communication channel (460), which can be a hardware / software link to a storage device where the encoded video data will be stored. The transmitter (440) can combine the encoded video data from the video encoder (403) with other data to be transmitted, such as encoded audio data and / or an auxiliary data stream (source not shown).

[0063] The controller (450) can manage the operation of the video encoder (403). During encoding, the controller (450) can assign a certain coded picture type to each coded picture, but this may affect the coding techniques that can be applied to the corresponding picture. For example, a picture can generally be assigned to any of the following picture types:

[0064] An intra picture (I-frame) is a picture that can be encoded and decoded without using any other picture in the sequence as a prediction source. Some video codecs allow different types of intra pictures, including, for example, Independent Decoder Refresh (IDR) pictures. Those skilled in the art are aware of the variations of I-frames and their corresponding applications and features.

[0065] Predictive pictures (P-frames), which may be pictures that can be encoded and decoded using intra prediction or inter prediction, which uses at most one motion vector and a reference index to predict sample values ​​for each block.

[0066] Bidirectionally predictive pictures (B-frames), which can be pictures that can be encoded and decoded using intra-frame prediction or inter-frame prediction, which uses up to two motion vectors and reference indices to predict the sample values ​​of each block. Similarly, multiple predictive pictures can use more than two reference pictures and associated metadata for reconstructing a single block.

[0067] A source picture is typically spatially subdivided into blocks of samples (e.g., blocks of 4×4, 8×8, 4×8, or 16×16 samples) and coded block by block. These blocks may be predictively coded with reference to other (already coded) blocks, determined according to the coding allocation applied to the block's corresponding picture. For example, a block of an I-frame may be non-predictively coded, or the block may be predictively coded (spatial prediction or intra-frame prediction) with reference to already coded blocks of the same picture. A pixel block of a P-frame may be predictively coded using spatial prediction with reference to one previously coded reference picture or using temporal prediction. A block of a B-frame may be predictively coded using spatial prediction with reference to one or two previously coded reference pictures or using temporal prediction.

[0068] The video encoder (403) may perform encoding operations according to a predetermined video coding technique or standard, such as ITU-T Recommendation H.265. In operation, the video encoder (403) may perform various compression operations, including predictive coding operations that exploit temporal and spatial redundancy in the input video sequence. Thus, the encoded video data may conform to the syntax specified by the video coding technique or standard used.

[0069] In an embodiment, the transmitter (440) may transmit additional data along with the encoded video. The source encoder (430) may include such data as part of the encoded video sequence. The additional data may include temporal / spatial / SNR enhancement layers, redundant pictures and slices, and other forms of redundant data, such as SEI (Supplementary Enhancement Information) messages, and VUI (Visual Usability Information) parameter set segments.

[0070] The captured video may be presented as a temporal sequence of multiple source pictures (video pictures). Intra-picture prediction (often shortened to intra prediction) exploits spatial correlation within a given picture, while inter-picture prediction exploits correlation (temporal or otherwise) between pictures. In an embodiment, a particular picture being encoded / decoded is divided into blocks, and the particular picture being encoded / decoded is referred to as the current picture. When a block in the current picture is similar to a reference block in a previously encoded and buffered reference picture in the video, the block in the current picture can be encoded using a vector called a motion vector. The motion vector points to the reference block in a reference picture, and when multiple reference pictures are used, the motion vector may have a third dimension that identifies the reference picture.

[0071] In some embodiments, bidirectional prediction techniques can be used for inter-picture prediction. According to bidirectional prediction techniques, two reference pictures are used, for example, a first reference picture and a second reference picture, both preceding the current picture in the video in decoding order (but potentially in the past and future, respectively, in display order). A block in the current picture can be encoded using a first motion vector pointing to a first reference block in the first reference picture and a second motion vector pointing to a second reference block in the second reference picture. Specifically, the block can be predicted using a combination of the first and second reference blocks.

[0072] In addition, merge mode technology can be used in inter-picture prediction to improve coding efficiency. In merge mode, a block in the current picture can inherit the motion vector of a neighboring block in the current picture (for example, a block that shares a boundary with the block in the current picture and is placed in a larger partition area with the block in the current picture).

[0073] According to some embodiments disclosed in the present application, predictions such as inter-picture prediction and intra-picture prediction are performed in units of blocks. For example, according to the HEVC standard, pictures in a video picture sequence are divided into coding tree units (CTUs) for compression, and the CTUs in the pictures have the same size, such as 64×64 pixels, 32×32 pixels, or 16×16 pixels. Generally speaking, a CTU includes three coding tree blocks (CTBs), which are a luminance CTB and two chrominance CTBs. Furthermore, each CTU can be split into one or more coding units (CUs) using a quadtree. For example, a 64×64 pixel CTU can be split into a 64×64 pixel CU, or four 32×32 pixel CUs, or sixteen 16×16 pixel CUs. In an embodiment, each CU is analyzed to determine the prediction type used for the CU, such as an inter prediction type or an intra prediction type. In addition, depending on temporal and / or spatial predictability, the CU is split into one or more prediction units (PUs). Typically, each PU includes a luma prediction block (PB) and two chroma PBs. In an embodiment, the prediction operation in encoding (encoding / decoding) is performed in units of prediction blocks. Taking the luma prediction block as an example, the prediction block includes a matrix of pixel values ​​(e.g., luma values), such as 8×8 pixels, 16×16 pixels, 8×16 pixels, 16×8 pixels, and the like.

[0074] Figure 5FIG2 is a diagram of a video encoder (503) according to another embodiment disclosed herein. The video encoder (503) is configured to receive a processed block (e.g., a prediction block) of sample values ​​within a current video picture in a sequence of video pictures and to encode the processed block into an encoded picture that is part of an encoded video sequence. In this embodiment, the video encoder (503) is configured to replace Figure 2 A video encoder (203) in an embodiment.

[0075] In an HEVC embodiment, a video encoder (503) receives a matrix of sample values ​​for a processing block, such as a prediction block of 8×8 samples. The video encoder (503) uses, for example, rate-distortion (RD) optimization to determine whether to use intra mode, inter mode, or bi-prediction mode to encode the processing block. When encoding the processing block in intra mode, the video encoder (503) may use intra prediction techniques to encode the processing block into an encoded picture; and when encoding the processing block in inter mode or bi-prediction mode, the video encoder (503) may use inter prediction or bi-prediction techniques, respectively, to encode the processing block into an encoded picture. In some video coding techniques, the merge mode may be an inter-picture prediction submode, in which a motion vector is derived from one or more motion vector predictors without resorting to coded motion vector components external to the predictor. In some other video coding techniques, there may be a motion vector component applicable to the subject block. In an embodiment, the video encoder (503) includes other components, such as a mode decision module (not shown) for determining the processing block mode.

[0076] exist Figure 5 In an embodiment of the present invention, the video encoder (503) includes Figure 5 Shown are an inter-frame encoder (530), an intra-frame encoder (522), a residual calculator (523), a switch (526), ​​a residual encoder (524), a general controller (521), and an entropy encoder (525) coupled together.

[0077] The inter-frame encoder (530) is used to receive samples of a current block (e.g., a processing block), compare the block with one or more reference blocks in a reference picture (e.g., blocks in a previous picture and a subsequent picture), generate inter-frame prediction information (e.g., redundant information description, motion vector, merge mode information according to an inter-frame coding technique), and calculate an inter-frame prediction result (e.g., a predicted block) based on the inter-frame prediction information using any suitable technique.

[0078] An intra-frame encoder (522) is configured to receive samples of a current block (e.g., a processing block), compare the block to already coded blocks in the same picture in some cases, generate quantized coefficients after transformation, and in some cases also generate intra-frame prediction information (e.g., intra-frame prediction direction information according to one or more intra-frame coding techniques).

[0079] The general controller (521) is used to determine general control data and control other components of the video encoder (503) based on the general control data. In an embodiment, the general controller (521) determines the mode of the block and provides a control signal to the switch (526) based on the mode. For example, when the mode is intra mode, the general controller (521) controls the switch (526) to select the intra mode result for use by the residual calculator (523) and controls the entropy encoder (525) to select intra prediction information and add the intra prediction information to the bitstream; and when the mode is inter mode, the general controller (521) controls the switch (526) to select the inter prediction result for use by the residual calculator (523) and controls the entropy encoder (525) to select inter prediction information and add the inter prediction information to the bitstream.

[0080] The residual calculator (523) is configured to calculate the difference (residual data) between the received block and a prediction result selected from the intra-frame encoder (622) or the inter-frame encoder (530). The residual encoder (524) is configured to operate based on the residual data to encode the residual data to generate transform coefficients. In an embodiment, the residual encoder (524) is configured to convert the residual data from the time domain to the frequency domain and generate transform coefficients. The transform coefficients are then quantized to obtain quantized transform coefficients.

[0081] The entropy encoder (525) is used to format the codestream to produce encoded blocks. The entropy encoder (525) generates various information according to a suitable standard, such as the HEVC standard. In an embodiment, the entropy encoder (525) is used to obtain general control data, selected prediction information (e.g., intra-frame prediction information or inter-frame prediction information), residual information, and other suitable information from the codestream. It should be noted that according to the disclosed subject matter, when encoding a block in inter-frame mode or the merge sub-mode of bidirectional prediction mode, there is no residual information.

[0082] Figure 6 FIG is a diagram of a video decoder (610) according to another embodiment disclosed in the present application. The video decoder (610) is configured to receive an encoded image as part of an encoded video sequence and decode the encoded image to generate a reconstructed picture. In an embodiment, the video decoder (610) is configured to replace Figure 2 A video decoder (210) of an embodiment.

[0083] exist Figure 6 In one embodiment, the video decoder (610) includes Figure 6 , an entropy decoder ( 671 ), an inter-frame decoder ( 680 ), a residual decoder ( 673 ), a reconstruction module ( 674 ), and an intra-frame decoder ( 672 ) coupled together are shown.

[0084] The entropy decoder (671) can be used to reconstruct certain symbols from the encoded picture, which represent syntax elements that constitute the encoded picture. Such symbols may include, for example, the mode used to encode the block (e.g., intra mode, inter mode, bidirectional prediction mode, a merged submode of the latter two, or another submode), prediction information (e.g., intra prediction information or inter prediction information) that can identify certain samples or metadata for prediction by the intra decoder (672) or the inter decoder (780), respectively, residual information in the form of, for example, quantized transform coefficients, etc. In an embodiment, when the prediction mode is inter or bidirectional prediction mode, the inter prediction information is provided to the inter decoder (680); and when the prediction type is intra prediction type, the intra prediction information is provided to the intra decoder (672). The residual information may be inverse quantized and provided to the residual decoder (673).

[0085] The inter-frame decoder (680) is used for receiving inter-frame prediction information and generating an inter-frame prediction result based on the inter-frame prediction information.

[0086] The intra-frame decoder (672) is configured to receive intra-frame prediction information and generate a prediction result based on the intra-frame prediction information.

[0087] The residual decoder (673) is used to perform inverse quantization to extract dequantized transform coefficients and process the dequantized transform coefficients to convert the residual from the frequency domain to the spatial domain. The residual decoder (673) may also require certain control information (to obtain the quantizer parameter QP), and this information can be provided by the entropy decoder (671) (the data path is not shown because this is only low-level control information).

[0088] The reconstruction module (674) is used to combine the residual output by the residual decoder (673) with the prediction result (which may be output by the inter-frame prediction module or the intra-frame prediction module) in the spatial domain to form a reconstructed block. The reconstructed block can be part of a reconstructed picture, which in turn can be part of a reconstructed video. It should be noted that other suitable operations such as deblocking operations can be performed to improve visual quality.

[0089] It should be noted that the video encoder (203), video encoder (403), and video encoder (503), as well as the video decoder (210), video decoder (310), and video decoder (610) may be implemented using any suitable technology. In an embodiment, the video encoder (203), video encoder (403), and video encoder (503), as well as the video decoder (210), video decoder (310), and video decoder (610) may be implemented using one or more integrated circuits. In another embodiment, the video encoder (203), video encoder (403), and video encoder (503), as well as the video decoder (210), video decoder (310), and video decoder (610) may be implemented using one or more processors that execute software instructions.

[0090] Figure 7A and 7B An embodiment of 35 intra-frame prediction modes, including 33 angular modes, is shown. Mode 0 is the intra-frame planar prediction mode, and Mode 1 is the intra-frame mean (INTRA_DC) prediction mode. Furthermore, Modes 2-34 represent intra-frame angular modes. As will be understood by those skilled in the art, Mode 10 is a horizontal angular mode, and Mode 26 is a vertical mode.

[0091] Figure 8A and 8B A total of 67 intra prediction modes, including 65 angular modes, are shown. Mode 0 is the intra-frame planar prediction mode, and mode 1 is the intra-frame mean (INTRA_DC) prediction mode. Furthermore, modes 2-66 represent the intra-frame angular modes INTRA_ANGULAR2-INTRA_ANGULAR66, respectively. As will be understood by those skilled in the art, mode 18 is a horizontal mode, and mode 50 is a vertical mode.

[0092] Figure 9 An embodiment of an exemplary angular mode for intra prediction is shown. Figure 9 In the figure, the lower right corner depicts an example including 9 prediction directions, which can be from the 35 possible prediction directions of H.265. The point (901) where the arrows converge represents the sample being predicted. The arrows represent the prediction directions of the samples. For example, arrow (902) indicates that sample (901) is predicted based on one or more samples to the upper right of sample (901) and at an angle of 45 degrees from the horizontal axis. Similarly, arrow (903) indicates that sample (901) is predicted based on one or more samples to the lower left of sample (901) and at an angle of 22.5 degrees from the horizontal axis.

[0093] Still refer to Figure 9, a square block (904) containing 4x4 samples is depicted in the upper left (shown by the dashed thick line). The square block (904) includes 16 samples, each of which is labeled "S", its position in the Y dimension (e.g., row index), and its position in the X dimension (e.g., column index). For example, sample S21 is the second sample in the Y dimension (from the top) and the first sample in the X dimension (from the left) in the square block (904). Similarly, sample S44 is the fourth sample in the X and Y dimensions in the square block (904). Since the square block (904) is 4x4 samples in size, sample S44 is in the lower right corner. Figure 9 Reference samples are further shown that follow a similar numbering strategy. Each reference sample is labeled with an "R," its Y position relative to the square block (904) (e.g., row index), and its X position relative to the square block (904) (column index). Intra-picture prediction can work by copying reference sample values ​​from adjacent samples according to a signaled prediction direction. For example, assume that the encoded video stream includes a signal for this block that indicates a prediction direction consistent with arrow (902) - that is, the sample is predicted based on one or more prediction samples that are located to the upper right of sample (901) and at a 45-degree angle from the horizontal axis. In this case, samples S41, S32, S23, and S14 are predicted based on the same reference sample R05. Next, sample S44 is predicted based on reference sample R08.

[0094] In some cases, the values ​​of multiple reference samples may be combined, for example by interpolation, to calculate the reference sample; in particular, when the directions are not evenly divisible into 45-degree angles.

[0095] Figure 10 An embodiment of multiple candidate reference lines for the current block 1000 is shown. The block 1000 and the associated candidate reference lines may be part of a larger picture. Figure 10 As shown, for intra directional mode, the number of candidate reference rows (e.g., rows or columns) ranges from 1 (i.e., the line closest to block 1000) to N, where in one embodiment, N is an integer greater than 1, and in another embodiment, N is equal to or greater than 1. Each reference row can be indexed from 1 to N (e.g., reference row (i)). For example, reference row (1) refers to reference rows 1002a and 1002b closest to block 1000. Reference row (2) refers to reference rows 1004a and 1004b. Reference row (3) refers to reference rows 1006a and 1006b. Reference row (N) refers to reference rows 1008a and 1008b farthest from block 1000.

[0096] The current block 1000 may be a 4x4 prediction unit (PU). One of N reference lines may be selected to calculate the prediction value. For example, the prediction value p(x, y) may be generated based on reference samples S1, S2, ..., SN, depending on which reference line is selected for intra prediction. In some embodiments, a flag is signaled to indicate which reference line is selected for intra directional mode. For example, if N is 4, a 2-bit flag may be used to indicate one of the following four different reference lines:

[0097] 00 = 1st reference row (e.g., 1002a, 1002b)

[0098] 01 = 2nd reference row (e.g., 1004a, 1004b)

[0099] 10 = 3rd reference row (e.g., 1006a, 1006b)

[0100] 11 = 4th reference row (e.g., 1008a, 1008b)

[0101] In some embodiments, for smooth areas, the first reference row (eg, 1002a, 1002b) takes precedence over other reference rows.

[0102] According to some embodiments, each reference line is associated with a different number of intra prediction modes. Figure 10 , when N is equal to 4, the 1st reference row (e.g., 1002a, 1002b) is associated with 67 patterns, the 2nd reference row (e.g., 1004a, 1004b) is associated with 35 patterns, the 3rd reference row (e.g., 1006a, 1006b) is associated with 17 patterns, and the 4th reference row (e.g., 1008a, 1008b) is associated with 9 patterns.

[0103] According to some embodiments, reference rows with indices greater than 1 (e.g., reference rows other than the reference row closest to the current block) are associated with the same number of inter-frame prediction modes, but fewer than the number of intra-frame prediction modes as the first reference row (e.g., 1002a, 1002b). For example, the first reference row (e.g., 1002a, 1002b) may be associated with 67 intra-frame prediction modes, and each of the remaining reference rows may be associated with 35 intra-frame prediction modes. As another example, the first reference row (e.g., 1002a, 1002b) may be associated with 67 intra-frame prediction modes, and each of the remaining reference rows may be associated with 17 intra-frame prediction modes. By specifying fewer prediction modes for reference rows other than the first reference row (e.g., 1002a, 1002b), a significant advantage is achieved in that computational complexity is reduced when performing intra-frame prediction on a block.

[0104] In some embodiments, a lookup table (LUT) may be used to store the relationship between each reference row and a number of intra-prediction modes associated with each reference row. For example, when there are four reference rows (e.g., N=4), the LUT may specify that the first reference row (e.g., 1002a, 1002b) is associated with 67 intra-prediction modes, and the second through fourth reference rows are each associated with 35 intra-prediction modes.

[0105] Figure 11 The process of an embodiment performed by an encoder or decoder, such as the intra encoder 522 or the intra decoder 672, is shown. The process generally begins at step S1100, where a reference line is determined for a current block in a picture from a plurality of reference lines. The plurality of reference lines may be two or more reference lines. For example, reference lines Figure 10 , a mark can be used to represent any one of reference lines 1 (eg, 1002a, 1002b) to N (1008a, 1008b).

[0106] The process continues to step S1102, where an intra prediction mode for the current block is determined based on the reference line determined from the plurality of reference lines. For example, the number of intra prediction modes associated with the determined reference line can be determined by querying a LUT that indicates the number of intra prediction modes associated with each reference line. When the number of intra prediction modes for the determined reference line is determined, the number of angle modes is also known in addition to the INTRA_PLANAR and INTRA_DC modes. For example, the reference line Figure 7A and 7B , when the LUT indicates that the number of intra prediction modes of the determined reference row is 35, the intra prediction mode of the current block can be any angle mode from angular mode 2 to 34. Figure 12 The specified process and the corresponding written description of U.S. patent application Ser. No. 16 / 147,544, filed on Sep. 28, 2018, entitled “Most Probable Mode Derivation Method and Apparatus,” can be used to determine an intra prediction mode for a current block. The entire contents of that U.S. patent application are incorporated herein by reference.

[0107] The process proceeds to step S1104, performing intra-frame prediction of the current block based on the determined intra-frame prediction mode and one or more samples contained in the reference line determined from the multiple reference lines. The multiple reference lines include adjacent reference lines and at least one non-adjacent reference line, wherein the adjacent reference line is adjacent to the current block, the at least one non-adjacent reference line is not adjacent to the current block, and the number of intra-frame prediction modes associated with each non-adjacent reference line in the at least one non-adjacent reference line is equal to or less than half the number of intra-frame prediction modes associated with the adjacent reference line. For example, the reference line Figure 10 , when the determined reference line is the second reference line (e.g., 1004a, 1004b), the reference line may be associated with 35 intra-frame prediction modes. Accordingly, if the intra-frame prediction mode of block 1000 is determined to be 18 (see, e.g., Figure 7B ), then sample S2 can be used to predict p(x,y).

[0108] The above techniques can be implemented as computer software through computer-readable instructions and physically stored in one or more computer-readable media. For example, Figure 12 A computer system (1200) suitable for implementing certain embodiments of the disclosed subject matter is shown.

[0109] The computer software may be encoded in any suitable machine code or computer language, and may be assembled, compiled, linked, or similar mechanisms to create code comprising instructions, which may be directly executed by one or more computer central processing units (CPUs), graphics processing units (GPUs), or the like, or executed through decoding, microcode, or the like.

[0110] The instructions may be executed on various types of computers or components thereof, including, for example, personal computers, tablets, servers, smartphones, gaming devices, IoT devices, and the like.

[0111] Figure 12 The components shown for the computer system (1200) are exemplary in nature and are not intended to suggest any limitation on the scope of use or functionality of computer software implementing embodiments of the invention. Nor should the configuration of components be interpreted as having any dependency or requirement on any one or combination of components illustrated in the exemplary embodiment of the computer system (1200).

[0112] The computer system (1200) may include certain human-computer interface input devices. The human-computer interface input devices may respond to input from one or more human users through tactile input (e.g., keyboard input, swiping, data glove movement), audio input (e.g., sound, applause), visual input (e.g., gestures), and olfactory input (not shown). The human-computer interface devices may also be used to capture certain media that are not necessarily directly related to conscious human input, such as audio (e.g., speech, music, ambient sound), images (e.g., scanned images, photographic images obtained from a still camera), and video (e.g., two-dimensional video, three-dimensional video including stereoscopic video).

[0113] The human-computer interface input device may include one or more of the following (only one of which is depicted): keyboard (1201), mouse (1202), touchpad (1203), touch screen (1210), data gloves (not shown), joystick (1205), microphone (1206), scanner (1207), camera (1208).

[0114] The computer system (1200) may also include certain human-computer interface output devices. The human-computer interface output devices may stimulate one or more senses of a human user through, for example, tactile output, sound, light, and smell / taste. The human-computer interface output devices may include tactile output devices (e.g., tactile feedback through a touch screen (1210), a data glove (not shown), or a joystick (1205), but there may also be tactile feedback devices that are not input devices), audio output devices (e.g., speakers (1209), headphones (not shown)), visual output devices (e.g., screens (1210) including cathode ray tube screens, liquid crystal screens, plasma screens, organic light emitting diode screens, each with or without touch screen input capabilities, tactile feedback capabilities—some of which may output two-dimensional visual outputs or outputs of more than three dimensions through means such as stereoscopic image output; virtual reality glasses (not shown), holographic displays, and cigarette boxes (not shown)), and printers (not shown).

[0115] The computer system (1200) may also include human-accessible storage devices and their associated media, such as optical media including media (1221) such as CD / DVD ROM / RW (1220) with CD / DVD, thumb drives (1222), removable hard drives or solid-state drives (1223), traditional magnetic media such as tapes and floppy disks (not shown), dedicated ROM / ASIC / PLD-based devices such as security software dongles (not shown), and the like.

[0116] Those skilled in the art will also understand that the term "computer-readable media" used in connection with the present subject matter does not include transmission media, carrier waves, or other transient signals.

[0117] The computer system (1200) may also include an interface to one or more communication networks. For example, the network may be wireless, wired, or optical. The network may also be a local area network, a wide area network, a metropolitan area network, an in-vehicle network, an industrial network, a real-time network, a delay-tolerant network, and the like. Networks also include local area networks such as Ethernet, wireless local area networks, cellular networks (GSM, 3G, 4G, 5G, LTE, etc.), television wired or wireless wide area digital networks (including cable television, satellite television, and terrestrial broadcast television), in-vehicle and industrial networks (including CANBus), and the like. Some networks typically require an external network interface adapter connected to some universal data port or peripheral bus (1249) (e.g., a USB port of the computer system (1200)); other systems are typically integrated into the core of the computer system (1200) by connecting to a system bus as described below (e.g., an Ethernet interface integrated into a PC computer system or a cellular network interface integrated into a smartphone computer system). By using any of these networks, the computer system (1200) can communicate with other entities. The communication can be one-way, for receiving only (e.g., wireless television), one-way, for sending only (e.g., a CAN bus to certain CAN bus devices), or two-way, such as to other computer systems via a local or wide area digital network. Each of the above networks and network interfaces can use certain protocols and protocol stacks.

[0118] The aforementioned human-machine interface devices, human-accessible storage devices, and network interfaces may be connected to the core (1240) of the computer system (1200).

[0119] The core (1240) may include one or more central processing units (CPUs) (1241), graphics processing units (GPUs) (1242), dedicated programmable processing units in the form of field programmable gate arrays (FPGAs) (1243), hardware accelerators (1244) for specific tasks, and the like. The aforementioned devices, as well as read-only memory (ROM) (1245), random access memory (1246), internal large-capacity storage (e.g., internal non-user accessible hard disk drives, SSDs, etc.) (1247), and the like, may be connected via a system bus (1248). In some computer systems, the system bus (1248) may be accessed in the form of one or more physical plugs for expansion with additional central processing units, graphics processing units, and the like. Peripheral devices may be attached directly to the core's system bus (1248) or connected via a peripheral bus (1249). Peripheral bus architectures include PCI (Peripheral Controller Interface), USB (Universal Serial Bus), and the like.

[0120] The CPU (1241), GPU (1242), FPGA (1243), and accelerator (1244) can execute certain instructions, which, when combined, can constitute the aforementioned computer code. The computer code can be stored in ROM (1245) or RAM (1246). Transient data can also be stored in RAM (1246), while permanent data can be stored, for example, in internal mass storage (1247). Fast storage and retrieval of any memory device can be achieved by using a cache, which can be closely associated with one or more CPUs (1241), GPUs (1242), mass storage (1147), ROM (1145), RAM (1146), etc.

[0121] The computer readable medium may have computer code for performing various computer-implemented operations. The medium and computer code may be specially designed and constructed for the purpose of the present invention, or may be medium and code well known and available to those skilled in the art of computer software.

[0122] As an example and not a limitation, a computer system having architecture (1200), in particular core (1240), can provide functionality as a processor (including a CPU, GPU, FPGA, accelerator, etc.) to execute software contained in one or more tangible computer-readable media. Such computer-readable media can be media associated with a user-accessible mass storage as described above, as well as specific memory of the core (1240) having non-transient properties, such as core internal mass storage (1247) or ROM (1245). Software implementing various embodiments of the present invention can be stored in such a device and executed by the core (1240). Depending on specific needs, the computer-readable medium may include one or more storage devices or chips. The software can cause the core (1240), in particular the processor therein (including a CPU, GPU, FPGA, etc.) to perform specific processes or specific parts of specific processes described herein, including defining data structures stored in RAM (1246) and modifying such data structures according to software-defined processes. Additionally or alternatively, the computer system may provide functionality hardwired in logic or otherwise contained in circuitry (e.g., accelerator (1244)) that may operate in place of or in conjunction with software to perform specific processes or specific portions of specific processes described herein. Where appropriate, references to software may include logic and vice versa. Where appropriate, references to computer-readable media may include circuitry (e.g., an integrated circuit (IC)) storing the executing software, circuitry containing the executing logic, or both. The present invention encompasses any suitable combination of hardware and software.

[0123] Appendix A: Acronyms

[0124] MV:Motion Vector

[0125] HEVC:High Efficiency Video Coding

[0126] SEI:Supplementary Enhancement Information

[0127] VUI:Video Usability Information

[0128] GOPs:Groups of Pictures

[0129] TUs:Transform Units,

[0130] PUs:Prediction Units

[0131] CTUs:Coding Tree Units

[0132] CTBs:Coding Tree Blocks

[0133] PBs:Prediction Blocks

[0134] HRD:Hypothetical Reference Decoder

[0135] SNR:Signal Noise Ratio

[0136] CPUs:Central Processing Units

[0137] GPUs:Graphics Processing Units

[0138] CRT:Cathode Ray Tube

[0139] LCD:Liquid-Crystal Display

[0140] OLED:Organic Light-Emitting Diode

[0141] CD:Compact Disc

[0142] DVD:Digital Video Disc

[0143] ROM:Read-Only Memory

[0144] RAM: Random Access Memory

[0145] ASIC:Application-Specific Integrated Circuit

[0146] PLD:Programmable Logic Device

[0147] LAN: Local Area Network

[0148] GSM:Global System for Mobile communications

[0149] LTE: Long-Term Evolution

[0150] CANBus:Controller Area Network Bus

[0151] USB: Universal Serial Bus

[0152] PCI: Peripheral Component Interconnect

[0153] FPGA:Field Programmable Gate Areas

[0154] SSD: solid-state drive

[0155] IC:Integrated Circuit

[0156] Although the present invention has been described with respect to a number of exemplary embodiments, various modifications, permutations, and substitutions of the embodiments are within the scope of the present invention. It should therefore be understood that those skilled in the art will be able to devise various systems and methods that, although not explicitly shown or described herein, embody the principles of the present invention and are therefore within the spirit and scope of the present invention.

[0157] (1) A method for video decoding, characterized in that it includes: determining a reference line for a current block in a picture from a plurality of reference lines, each reference line in the plurality of reference lines being parallel to a side of the current block; determining an intra-frame prediction mode of the current block based on the reference line determined from the plurality of reference lines; performing intra-frame prediction of the current block based on the determined intra-frame prediction mode and one or more samples contained in the reference line determined from the plurality of reference lines; wherein the plurality of reference lines include adjacent reference lines and at least one non-adjacent reference line, wherein the adjacent reference lines are adjacent to the current block, the at least one non-adjacent reference line is not adjacent to the current block, and the number of intra-frame prediction modes associated with each non-adjacent reference line in the at least one non-adjacent reference line is equal to or less than half the number of intra-frame prediction modes associated with the adjacent reference lines.

[0158] (2) The method according to feature (1), wherein for each non-adjacent reference line in the at least one non-adjacent reference line, the number of associated intra prediction modes is the same.

[0159] (3) The method according to feature (1), wherein, for each non-adjacent reference line of the at least one non-adjacent reference line, the number of its associated intra-frame prediction modes decreases as the distance from the current block increases.

[0160] (4) A method according to any one of features (1) to (3), wherein the number of intra-frame prediction modes associated with the adjacent reference lines is 67, and the number of intra-frame prediction modes associated with each non-adjacent reference line in the at least one non-adjacent reference line is equal to or less than 33.

[0161] (5) A method according to any one of features (1) to (4), wherein each of the multiple reference lines is a line above the current block.

[0162] (6) A method according to any one of features (1) to (5), wherein each of the multiple reference rows is a column to the left of the current block.

[0163] (7) A video decoder for video decoding, comprising: a processing circuit, configured to: determine a reference line for a current block in a picture from a plurality of reference lines, each reference line in the plurality of reference lines being parallel to a side of the current block; determine an intra-frame prediction mode of the current block based on the reference line determined from the plurality of reference lines; perform intra-frame prediction of the current block based on the determined intra-frame prediction mode and one or more samples contained in the reference line determined from the plurality of reference lines; wherein the plurality of reference lines include adjacent reference lines and at least one non-adjacent reference line, wherein the adjacent reference lines are adjacent to the current block, the at least one non-adjacent reference line is not adjacent to the current block, and the number of intra-frame prediction modes associated with each non-adjacent reference line in the at least one non-adjacent reference line is equal to or less than half the number of intra-frame prediction modes associated with the adjacent reference lines.

[0164] (8) The video decoder of feature (7), wherein for each non-adjacent reference line in the at least one non-adjacent reference line, the number of associated intra prediction modes is the same.

[0165] (9) A video decoder according to feature (7), wherein for each of the at least one non-adjacent reference lines, the number of intra prediction modes associated therewith decreases as the distance from the current block increases.

[0166] (10) A video decoder according to any one of features (7) to (9), wherein the number of intra-frame prediction modes associated with the adjacent reference lines is 67, and the number of intra-frame prediction modes associated with each non-adjacent reference line in the at least one non-adjacent reference line is equal to or less than 33.

[0167] (11) A video decoder according to any one of features (7) to (10), wherein each reference line of the plurality of reference lines is a line above the current block.

[0168] (12) A video decoder according to any one of features (7) to (11), wherein each reference line of the plurality of reference lines is a column to the left of the current block.

[0169] (13) A non-volatile computer-readable storage medium storing a plurality of instructions, wherein when the instructions are executed by a processor in a video decoder, the processor is caused to perform a method comprising: determining a reference line for a current block in a picture from a plurality of reference lines, each reference line in the plurality of reference lines being parallel to a side of the current block; determining an intra-frame prediction mode of the current block based on the reference line determined from the plurality of reference lines; performing intra-frame prediction of the current block based on the determined intra-frame prediction mode and one or more samples contained in the reference line determined from the plurality of reference lines; wherein the plurality of reference lines include adjacent reference lines and at least one non-adjacent reference line, wherein the adjacent reference lines are adjacent to the current block, the at least one non-adjacent reference line is not adjacent to the current block, and the number of intra-frame prediction modes associated with each of the at least one non-adjacent reference lines is equal to or less than half the number of intra-frame prediction modes associated with the adjacent reference lines.

[0170] (14) The non-transitory computer-readable medium of feature (13), wherein for each of the at least one non-adjacent reference lines, the number of associated intra prediction modes is the same.

[0171] (15) The non-transitory computer-readable medium of feature (13), wherein for each of the at least one non-adjacent reference lines, the number of associated intra-frame prediction modes decreases as the distance from the current block increases.

[0172] (16) A non-volatile computer-readable medium according to any one of features (13) to (15), wherein the number of intra-frame prediction modes associated with the adjacent reference rows is 67, and the number of intra-frame prediction modes associated with each of the at least one non-adjacent reference rows is equal to or less than 33.

[0173] (17) The non-transitory computer-readable medium of any one of features (13) to (16), wherein each of the plurality of reference rows is a row above the current block.

[0174] (18) The non-transitory computer-readable medium of any one of features (13) to (17), wherein each of the plurality of reference rows is a column to the left of the current block.

Claims

1. A video decoding method, characterized in that: include: receiving a flag for a current block, the flag indicating a reference line of a plurality of reference lines, each reference line of the plurality of reference lines being parallel to a side of the current block; determining the one reference line among the plurality of reference lines according to the flag; determining an intra prediction mode for the current block based on the one reference line determined from the plurality of reference lines; performing intra prediction of the current block according to the determined intra prediction mode and one or more samples included in the reference line determined from the plurality of reference lines; The multiple reference rows include adjacent reference rows and at least one non-adjacent reference row, wherein the adjacent reference row is adjacent to the current block, and the at least one non-adjacent reference row is not adjacent to the current block, and for each non-adjacent reference row of the at least one non-adjacent reference row, the number of associated first intra-frame prediction modes is the same, and the number of first intra-frame prediction modes of each non-adjacent reference row is less than or equal to the number of second intra-frame prediction modes associated with the adjacent reference row.

2. The method according to claim 1, characterized in that For each non-adjacent reference line of the at least one non-adjacent reference line, as the distance from the current block increases, the number of first intra prediction modes associated therewith decreases.

3. The method according to claim 1, characterized in that Each of the plurality of reference lines is a line above the current block.

4. The method according to claim 1, wherein Each of the plurality of reference rows is a column to the left of the current block.

5. A video decoder for video decoding, characterized in that include: Processing circuitry for: receiving a flag for a current block, the flag indicating a reference line of a plurality of reference lines, each reference line of the plurality of reference lines being parallel to a side of the current block; determining the one reference row among the plurality of reference rows according to the flag; determining an intra prediction mode for the current block based on the one reference line determined from the plurality of reference lines; performing intra prediction of the current block according to the determined intra prediction mode and one or more samples included in the reference line determined from the plurality of reference lines; The multiple reference rows include adjacent reference rows and at least one non-adjacent reference row, wherein the adjacent reference row is adjacent to the current block, and the at least one non-adjacent reference row is not adjacent to the current block, and for each non-adjacent reference row of the at least one non-adjacent reference row, the number of associated first intra-frame prediction modes is the same, and the number of first intra-frame prediction modes of each non-adjacent reference row is less than or equal to the number of second intra-frame prediction modes associated with the adjacent reference row.

6. The video decoder according to claim 5, wherein: For each non-adjacent reference line of the at least one non-adjacent reference line, as the distance from the current block increases, the number of first intra prediction modes associated therewith decreases.

7. The video decoder according to claim 5, wherein: Each reference line of the plurality of reference lines is a line above the current block.

8. The video decoder according to any one of claims 5 to 6, characterized in that: Each of the plurality of reference lines is a column on the left side of the current block.

9. A video decoder for video decoding, characterized in that include: a processing module configured to: receive a flag for a current block, the flag indicating a reference line from a plurality of reference lines, each reference line from the plurality of reference lines being parallel to a side of the current block; determine the reference line from the plurality of reference lines based on the flag; and determine an intra prediction mode for the current block based on the reference line determined from the plurality of reference lines; and performing intra-frame prediction of the current block based on the determined intra-frame prediction mode and one or more samples contained in the reference row determined from the multiple reference rows; wherein the multiple reference rows include adjacent reference rows and at least one non-adjacent reference row, wherein the adjacent reference row is adjacent to the current block, and the at least one non-adjacent reference row is not adjacent to the current block, and for each non-adjacent reference row of the at least one non-adjacent reference row, the number of its associated first intra-frame prediction modes is the same, and the number of first intra-frame prediction modes of each non-adjacent reference row is less than or equal to the number of second intra-frame prediction modes associated with the adjacent reference row.

10. A video encoding method, comprising: determining a flag for a current block of a picture, the flag indicating a reference line from a plurality of reference lines, each reference line in the plurality of reference lines being parallel to a side of the current block; determining the one reference row among the plurality of reference rows according to the flag; determining an intra prediction mode for the current block based on the one reference line determined from the plurality of reference lines; performing intra prediction of the current block according to the determined intra prediction mode and one or more samples included in the reference line determined from the plurality of reference lines; The multiple reference rows include adjacent reference rows and at least one non-adjacent reference row, wherein the adjacent reference row is adjacent to the current block, and the at least one non-adjacent reference row is not adjacent to the current block, and for each non-adjacent reference row of the at least one non-adjacent reference row, the number of associated first intra-frame prediction modes is the same, and the number of first intra-frame prediction modes of each non-adjacent reference row is less than or equal to the number of second intra-frame prediction modes associated with the adjacent reference row.

11. A computer-readable storage medium storing instructions, characterized in that: When the instruction is executed by a video codec, the method according to any one of claims 1 to 4 is implemented.

12. A method for storing a video bitstream, characterized in that: Execute the video encoding method according to claim 10 to generate a video bit stream; and store the video bit stream.

13. A method for transmitting a video bitstream, characterized in that: Execute the video encoding method according to claim 10 to generate a video bit stream; and transmit the video bit stream.

14. A computer-readable storage medium having stored thereon a computer program and a video bitstream, characterized in that: When the computer program is executed by a processor, the computer program implements the steps of the video encoding method according to claim 10 to generate the video bit stream.

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