Video coding and decoding method and device, readable medium and computer system

Abstract

Aspects of the present disclosure provide a method, apparatus, readable medium, and computer system for video decoding. In some examples, an apparatus for video decoding includes receiving circuitry and processing circuitry. In some embodiments, processing circuitry decodes prediction information for a block in an I-slice from an encoded video bitstream and determines whether an IBC mode is available for the block in the I-slice. In response to a slice type parameter indicating the I slice and at least one of a width or a height of the block being greater than 64, a current mode type parameter is set to an intra coding mode. Further, in an embodiment, processing circuitry decodes a skip flag indicating whether to apply a skip mode to a block from an encoded video bitstream in response to the IBC mode being available for the block. The processing circuitry then reconstructs the block based at least in part on the skip flag.

Description

[0001] Incorporation by Reference

[0002] This application claims priority to U.S. Patent Application No. 17 / 095,583, filed on November 11, 2020, "METHOD AND APPARATUS FOR SIGNALING SKIP MODE FLAG," which claims priority to U.S. Provisional Application No. 62 / 959,621, filed on January 10, 2020, "METHODS FOR SIGNALING OF SKIP MODE FLAG." The entire disclosures of these prior applications are hereby incorporated by reference in their entirety. Technical Field

[0003] This application describes embodiments that generally relate to video encoding and decoding. Background Art

[0004] The background description provided herein is intended to present the background of the present application as a whole. The extent to which the work of the presently named inventors described in the background section and various aspects of this specification is performed does not indicate that it is prior art at the time of filing this application, and it is never explicitly or implicitly admitted that it is prior art for this application.

[0005] Video encoding and decoding are possible through inter-picture prediction and intra-picture prediction techniques. An uncompressed digital video may include a series of pictures, each picture having a spatial dimension of, for example, 1920×1080 luminance samples and associated chrominance samples. The series of pictures has a fixed or variable picture rate (also informally referred to as a frame rate), such as 60 pictures per second or 60Hz. Uncompressed video has very large bit rate requirements. For example, 1080p60 4:2:0 video (1920x1080 luminance sample resolution, 60Hz frame rate) with 8 bits per sample requires close to 1.5Gbit / s bandwidth. One hour of such video requires more than 600GB of storage space.

[0006] One goal of video encoding and decoding is to reduce redundant information in the input video signal through compression. Video compression can help reduce the bandwidth or storage space requirements mentioned above, in some cases by two or more orders of magnitude. Both lossless and lossy compression, as well as combinations of the two, can be used. Lossless compression refers to techniques that reconstruct an exact replica of the original signal from the compressed original signal. When lossy compression is used, the reconstructed signal may not be exactly the same as the original signal, but the distortion between the original and the reconstructed signal is small enough that the reconstructed signal can be used for the intended application. Lossy compression is widely used in video. The amount of distortion allowed depends on the application. For example, users of some consumer streaming applications may tolerate higher distortion than users of television applications. The achievable compression ratio reflects that higher allowed / tolerable distortion results in higher compression ratios.

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

[0008] Video codec techniques may include known intra-frame coding techniques. In intra-frame coding, sample values ​​are represented without reference to samples or other data of previously reconstructed reference pictures. In some video codecs, pictures are spatially subdivided into blocks of samples. When all sample blocks are encoded in intra-frame mode, the picture may be an intra-frame picture. Intra-frame pictures and their derivatives (e.g., independent decoder refresh pictures) may be used to reset decoder states, and may therefore be used as the first picture in a coded video bitstream and video session, or as a still image. Samples of intra-frame blocks may be used for transformation, and transform coefficients may be quantized before entropy coding. Intra-frame prediction may be a technique for minimizing sample values ​​in a pre-transform domain. In some cases, the smaller the DC value after transformation, and the smaller the AC coefficient, the fewer bits are needed to represent the block after entropy coding at a given quantization step size.

[0009] Conventional intra-frame coding, as known from coding techniques such as MPEG-2, does not use intra-frame prediction. However, some newer video compression techniques include techniques that attempt to derive data blocks from, for example, surrounding sample data and / or metadata, which are obtained during spatially adjacent encoding / decoding and before the decoding order. Such techniques have subsequently been referred to as "intra-frame prediction" techniques. It should be noted that, at least in some cases, intra-frame prediction uses only reference data of the current picture being reconstructed, and not reference data of reference pictures.

[0010] There can be many different forms of intra-frame prediction. When more than one such technique can be used in a given video coding technique, the techniques used can be encoded as intra-frame prediction modes. In some cases, a mode can have sub-modes and / or parameters, and these modes can be encoded separately or contained in a mode codeword. Which codeword is used for a given mode / sub-mode / parameter combination affects the coding efficiency gain through intra-frame prediction, and therefore the entropy coding technique used to convert the codeword into a bitstream.

[0011] H.264 introduced an intra prediction mode, which was improved in H.265 and further improved in newer coding techniques such as the Joint Exploration Model (JEM), Versatile Video Coding (VVC), Benchmark Sets (BMS), etc. A prediction block can be formed by using neighboring sample values ​​belonging to samples that are already available. The sample values ​​of neighboring samples are copied to the prediction block in a certain direction. A reference to the direction used can be encoded in the bitstream or can itself be predicted.

[0012] Reference Figure 1 , a subset of nine known prediction directions from the 33 possible prediction directions of H.265 (corresponding to 33 angular modes in 35 internal modes) is depicted at the lower right. The point (101) where the arrows converge represents the sample being predicted. The arrows represent the direction in which the sample is being predicted. For example, arrow (102) indicates that sample (101) is predicted based on one or more samples at a 45 degree angle to the horizontal direction at the upper right. Similarly, arrow (103) indicates that sample (101) is predicted based on one or more samples at a 22.5 degree angle to the horizontal direction at the lower left.

[0013] Still reference Figure 1 , a square block (104) consisting of 4×4 samples is shown in the upper left (indicated by the thick dashed line). The square block (104) consists of 16 samples, each of which is labeled with "S" and 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 (starting from the top) and the first sample in the X dimension (starting from the left). Similarly, sample S44 is the fourth sample in the block (104) in both the Y dimension and the X dimension. Since the block is a 4×4 size sample, S44 is located in the lower right corner. Reference samples following a similar numbering scheme are also shown. Reference samples are labeled with "R" and their Y position (e.g., row index) and X position (e.g., column index) relative to the block (104). In H.264 and H.265, the prediction samples are adjacent to the block being reconstructed, so negative values ​​do not need to be used.

[0014] Intra-picture prediction can be performed by copying reference sample values ​​from neighboring samples occupied by a signaled prediction direction. For example, assume that the encoded video bitstream includes signaling that, for this block, indicates a prediction direction consistent with arrow (102), i.e., the sample is predicted based on one or more prediction samples to the upper right at a 45 degree angle to the horizontal direction. In this case, samples S41, S32, S23, and S14 are predicted based on the same reference sample R05. Then, sample S44 is predicted based on reference sample R08.

[0015] In some cases, for example by interpolation, the values ​​of multiple reference samples may be combined in order to calculate the reference sample, particularly when the direction is not divisible by 45 degrees.

[0016] As video coding techniques have evolved, the number of possible directions has increased. In H.264 (2003), nine different directions could be represented. This increased to 33 in H.265 (2013) and JEM / VVC / BMS, and at the time of this application, up to 65 directions can be supported. Experiments have been conducted to identify the most likely directions, and certain techniques in entropy coding are used to represent those possible directions using a small number of bits, accepting some penalty for less likely directions. Additionally, the direction itself can sometimes be predicted based on neighboring directions used in adjacent, already decoded blocks.

[0017] Figure 2 is a schematic diagram 201 depicting 65 intra prediction directions according to JEM to illustrate the increase in the number of prediction directions over time.

[0018] The mapping of the intra prediction direction bits in the coded video bitstream representing the direction may vary from one video coding technique to another, and may, for example, range from a simple direct mapping of the prediction direction of the intra prediction mode to the codeword, to complex adaptive schemes including the most probable mode and similar techniques. However, in all cases, there may be certain directions in the video content that are statistically less likely to occur than other directions. Since the goal of video compression is to reduce redundancy, in a well-functioning video coding technique, those less likely directions will be represented using a larger number of bits than more likely directions.

[0019] Motion compensation may be a lossy compression technique and may involve the following technique: a block of sample data from a previously reconstructed picture or part thereof (reference picture), after being spatially shifted in a direction indicated by a motion vector (hereinafter MV), is used for the prediction of a newly reconstructed picture or part of a picture. In some cases, the reference picture may be the same as the picture currently being reconstructed. The MV may have two dimensions, X and Y, or three dimensions, the third dimension indicating the reference picture in use (indirectly, the latter may be the temporal dimension).

[0020] In some video compression techniques, an MV that can be applied to a certain area of ​​sample data can be predicted from other MVs, such as those MVs that are related to another area of ​​sample data that is spatially adjacent to the area being reconstructed and that precede the MV in decoding order. Doing so can significantly reduce the amount of data required to encode the MV, thereby eliminating redundancy and increasing compression. MV prediction can work effectively, for example, because when encoding an input video signal derived from a camera (called natural video), areas larger than the area where a single MV is applicable are statistically likely to move in similar directions. Therefore, in some cases these areas (areas larger than the area where a single MV is applicable) can be predicted using similar motion vectors derived from MVs of adjacent areas. This results in the MV found for a given area being similar or identical to the MV predicted from the surrounding MVs, and compared to encoding the MV directly, after entropy coding, the MV in turn can be represented with fewer bits than when the MV is directly encoded. In some cases, MV prediction can be an example of lossless compression of a signal (i.e., MV) derived from the original signal (i.e., sample stream). In other cases, the MV prediction itself may be lossy, for example due to rounding errors when computing the prediction value from several surrounding MVs.

[0021] Various MV prediction mechanisms are described in H.265 / HEVC (ITU-T H.265 Recommendation, "High Efficiency Video Coding", December 2016). Among the various MV prediction mechanisms provided by H.265, this application describes a technique referred to below as "spatial merging".

[0022] Please refer to Figure 3, the current block (301) includes samples that have been discovered by the encoder during the motion search process, and the samples can be predicted based on the previous block of the same size that has generated a spatial offset. In addition, the MV can be derived from metadata associated with one or more reference pictures instead of encoding the MV directly. For example, the MV is derived from the metadata of the nearest reference picture (in decoding order) using the MV associated with any of the five surrounding samples A0, A1 and B0, B1, B2 (corresponding to 302 to 306 respectively). In H.265, MV prediction can use the prediction value of the same reference picture that the neighboring blocks are also using. Summary of the invention

[0023] Aspects of the present disclosure provide methods, devices, readable media, and computer systems for video decoding. In some examples, the apparatus for video decoding includes a receiving circuit and a processing circuit. In some embodiments, the processing circuit decodes prediction information of a block in an I slice from an encoded video code stream, and determines whether the IBC mode can be used for the block in the I slice based on the prediction information and the size limit of the intra-frame block copy IBC mode. In addition, in an embodiment, the processing circuit decodes a skip flag indicating whether a skip mode is applied to the block from the encoded video code stream in response to the IBC mode being available for the block. Then, the processing circuit reconstructs the block based at least in part on the skip flag.

[0024] In some examples, the processing circuit further sets the current mode type parameter to the intra coding mode in response to the slice type parameter indicating the I slice and at least one of the width or height of the block being greater than 64. For example, the intra coding mode is indicated by the identifier MODE_TYPE_INTRA.

[0025] Furthermore, in some examples, processing circuitry infers the skip flag in response to the IBC mode being unavailable for the block in the I slice.

[0026] In some embodiments, the processing circuit determines that the IBC mode is not applicable to the block in the I slice in response to the size of the block in the I slice being greater than a size threshold of the IBC mode. In an embodiment, the processing circuit determines that the IBC mode is not applicable to the block in the I slice in response to at least one of the width of the block and the height of the block being greater than the size threshold of the IBC mode. In some examples, the processing circuit determines that the skip flag exists in the encoded video bitstream based on an added condition. The added condition is to compare the size of the block with the size threshold of the IBC mode. Excluding the presence of the skip flag in the encoded video bitstream in response to the size of the block in the I slice being greater than the size threshold.

[0027] In some examples, the processing circuit determines the presence of the flag in the encoded video stream based on an existing condition modified to compare the size of the block to a size threshold of the IBC mode. In one example, the existing condition is determining whether the block is an inter-coded block. In another example, the existing condition is determining whether the IBC mode is enabled.

[0028] Aspects of the present disclosure also provide a method for video decoding, including:

[0029] Decode the prediction information of the blocks in the I slice from the encoded video bitstream;

[0030] determining whether the intra block copy (IBC) mode is applicable to the block in the I slice based on the prediction information and a size restriction of the IBC mode;

[0031] In response to the slice type parameter indicating the I slice, and at least one of the width or the height of the block being greater than 64, setting the current mode type parameter to an intra coding mode;

[0032] In response to the IBC mode being applicable to the block, decoding a skip flag indicating whether a skip mode is applied to the block from the encoded video stream; and

[0033] The block is reconstructed based at least in part on the skip flag.

[0034] Aspects of the present disclosure also provide a non-transitory computer-readable medium storing instructions, which, when executed by a computer for video decoding, cause the computer to perform a method for video decoding.

[0035] Aspects of the present disclosure also provide a computer system, which includes: one or more computer-readable non-volatile storage media, configured to store computer program code; and one or more computer processors, configured to access the computer program code and operate according to the instructions of the computer program code to execute the video decoding method. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Other features, properties and various advantages of the disclosed subject matter will become further apparent from the following detailed description and accompanying drawings, in which:

[0037] Figure 1 is a schematic diagram of an example subset of intra prediction modes;

[0038] Figure 2 is a diagram of exemplary intra prediction directions;

[0039] Figure 3 is a schematic diagram of the current block and its surrounding spatial merging candidates in an example;

[0040] Figure 4 is a schematic diagram of a simplified block diagram of a communication system according to an embodiment;

[0041] Figure 5 is a schematic diagram of a simplified block diagram of a communication system according to an embodiment;

[0042] Figure 6 is a schematic diagram of a simplified block diagram of a decoder according to an embodiment;

[0043] Figure 7 is a schematic diagram of a simplified block diagram of an encoder according to an embodiment;

[0044] Figure 8 shows a block diagram of an encoder according to an embodiment;

[0045] Fig. 9 shows a block diagram of a decoder according to an embodiment;

[0046] Fig.10 An example of intra-block copying according to an embodiment of the present disclosure is shown;

[0047] Fig.11 An exemplary syntax table for signaling prediction mode at the codec unit level is shown;

[0048] FIG. 12A to FIG. 12E An exemplary syntax table at the coding tree unit level is shown;

[0049] Fig.13 shows an exemplary syntax table at the codec unit level according to some embodiments of the present disclosure;

[0050] Fig.14 shows an exemplary syntax table for a coding tree level according to some embodiments of the present disclosure;

[0051] Fig.15 A flowchart outlining an example of a process according to some embodiments of the present disclosure is shown;

[0052] Fig.16 is a schematic diagram of a computer system according to an embodiment. DETAILED DESCRIPTION

[0053] Figure 4 4 is a simplified block diagram of a communication system (400) according to an embodiment disclosed in the present application. The communication system (400) includes a plurality of terminal devices, which can communicate with each other through, for example, a network (450). For example, the communication system (400) includes a first terminal device (410) and a second terminal device (420) interconnected through the network (450). Figure 4In an embodiment of the present invention, the first terminal device (410) and the second terminal device (420) perform unidirectional data transmission. For example, the first terminal device (410) may encode video data (e.g., a video picture stream collected by the terminal device (410)) for transmission to the second terminal device (420) via the network (450). The encoded video data is transmitted in the form of one or more encoded video code streams. The second terminal device (420) may receive the encoded video data from the network (450), 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.

[0054] In another embodiment, the communication system (400) includes a third terminal device (430) and a fourth terminal device (440) that perform bidirectional transmission of encoded video data, which can occur, for example, during a video conference. For bidirectional data transmission, each of the third terminal device (430) and the fourth terminal device (440) can encode video data (e.g., a video picture stream collected by the terminal device) to transmit to the other terminal device of the third terminal device (430) and the fourth terminal device (440) through a network (450). Each of the third terminal device (430) and the fourth terminal device (440) can also receive the encoded video data transmitted by the other terminal device of the third terminal device (430) and the fourth terminal device (440), 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.

[0055] exist Figure 4 In the embodiment of the present invention, the first terminal device (410), the second terminal device (420), the third terminal device (430) and the fourth terminal device (440) may be servers, personal computers and smart phones, but the principles disclosed in the present application may not be limited thereto. The embodiments disclosed in the present application are applicable to laptop computers, tablet computers, media players and / or dedicated video conferencing equipment. The network (450) represents any number of networks that transmit encoded video data between the first terminal device (410), the second terminal device (440), the third terminal device (430) and the fourth terminal device (440), including, for example, wired (wired) and / or wireless communication networks. The communication network (450) 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 the present application, unless explained below, the architecture and topology of the network (450) may be irrelevant to the operations disclosed in the present application.

[0056] As an example, Figure 5The 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.

[0057] The streaming system may include an acquisition subsystem (513), which may include a video source (501) such as a digital camera, which creates an uncompressed video picture stream (502). In an embodiment, the video picture stream (502) includes samples taken by a digital camera. Compared to the encoded video data (504) (or the encoded video bitstream), the video picture stream (502) is depicted as a thick line to emphasize the high data volume of the video picture stream, and the video picture stream (502) can be processed by an electronic device (520), which includes a video encoder (503) coupled to the video source (501). The video encoder (503) 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 (502), the encoded video data (504) (or the encoded video bitstream (504)) is depicted as a thin line to emphasize the lower amount of data of the encoded video data (504) (or the encoded video bitstream (504)), which can be stored on the streaming server (505) for future use. One or more streaming client subsystems, such as Figure 5 The client subsystem (506) and the client subsystem (508) in the streaming server (505) can access the streaming server (505) to retrieve the copy (507) and the copy (509) of the encoded video data (504). The client subsystem (506) may include, for example, a video decoder (510) in the electronic device (530). The video decoder (510) decodes the incoming copy (507) of the encoded video data and generates an output video picture stream (511) that can be presented on a display (512) (e.g., a display screen) or another presentation device (not depicted). In some streaming systems, the encoded video data (504), the video data (507), and the video data (509) (e.g., a video bitstream) can be encoded according to certain video encoding / compression standards. Examples of these 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.

[0058] It should be noted that the electronic device (520) and the electronic device (530) may include other components (not shown). For example, the electronic device (520) may include a video decoder (not shown), and the electronic device (530) may also include a video encoder (not shown).

[0059] Figure 6 6 is a block diagram of a video decoder (610) according to an embodiment disclosed in the present application. The video decoder (610) may be provided in an electronic device (630). The electronic device (630) may include a receiver (631) (e.g., a receiving circuit). The video decoder (610) may be used to replace Figure 5 A video decoder (510) of an embodiment.

[0060] The receiver (631) may receive one or more encoded video sequences to be decoded by the video decoder (610); in the same or another embodiment, one encoded video sequence is received at a time, wherein the decoding of each encoded video sequence is independent of the other encoded video sequences. The encoded video sequence may be received from a channel (601), which may be a hardware / software link to a storage device storing the encoded video data. The receiver (631) may receive the encoded video data as well as other data, such as encoded audio data and / or auxiliary data streams that may be forwarded to their respective consuming entities (not shown). The receiver (631) may separate the encoded video sequence from the other data. To prevent network jitter, a buffer memory (615) may be coupled between the receiver (631) and the entropy decoder / parser (620) (hereinafter referred to as "parser (620)"). In some applications, the buffer memory (615) is part of the video decoder (610). In other cases, the buffer memory (615) may be provided external to the video decoder (610) (not shown). In other cases, a buffer memory (not shown) is provided outside the video decoder (610) to prevent network jitter, for example, and another buffer memory (615) may be configured inside the video decoder (610) to handle broadcast timing, for example. When the receiver (631) receives data from a storage / forward device with sufficient bandwidth and controllability or from an isochronous network, it may not be necessary to configure the buffer memory (615), or the buffer memory may be made smaller. Of course, in order to use on a service packet network such as the Internet, a buffer memory (615) may also be required, and the buffer memory may be relatively large and have an adaptive size, and may be at least partially implemented in an operating system or a similar element (not shown) outside the video decoder (610).

[0061] The video decoder (610) may include a parser (620) to reconstruct symbols (621) from the encoded video sequence. The types of symbols include information used to manage the operation of the video decoder (610) and potential information used to control a display device such as a display device (612) (e.g., a display screen) that is not part of the electronic device (630) but can be coupled to the electronic device (630), such as Figure 6 As shown in . The control information for the display device may be a parameter set fragment (not indicated) of Supplemental Enhancement Information (SEI message) or Video Usability Information (VUI). The parser (620) may parse / entropy decode the received coded video sequence. The encoding 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 (620) may extract a subgroup parameter set of 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 (620) may also extract information from the encoded video sequence, such as transform coefficients, quantizer parameter values, motion vectors, and so on.

[0062] The parser (620) may perform entropy decoding / parsing operations on the video sequence received from the buffer memory (615), thereby creating symbols (621).

[0063] Depending on the type of coded video picture or portion of coded video picture (e.g., inter- and intra-pictures, inter- and intra-blocks) and other factors, the reconstruction of the symbol (621) may involve multiple different units. Which units are involved and how they are involved may be controlled by subgroup control information parsed by the parser (620) from the coded video sequence. For the sake of brevity, such subgroup control information flow between the parser (620) and the multiple units below is not described.

[0064] In addition to the functional blocks already mentioned, the video decoder (610) can be conceptually subdivided into several functional units as described below. In a practical embodiment operating under commercial constraints, many of these units interact closely with each other and can be integrated with each other. However, for the purpose of describing the disclosed subject matter, the conceptual subdivision into the following functional units is appropriate.

[0065] The first unit is a sealer / inverse transform unit (651). The sealer / inverse transform unit (651) receives quantized transform coefficients as symbols (621) from the parser (620) and control information, including which transform method to use, block size, quantization factor, quantization scaling matrix, etc. The sealer / inverse transform unit (651) can output a block including sample values, which can be input into an aggregator (655).

[0066] In some cases, the output samples of the scaler / inverse transform unit (651) 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 an intra-picture prediction unit (652). In some cases, the intra-picture prediction unit (652) generates surrounding blocks of the same size and shape as the block being reconstructed using reconstructed information extracted from a current picture buffer (658). For example, the current picture buffer (658) buffers a partially reconstructed current picture and / or a fully reconstructed current picture. In some cases, the aggregator (655) adds the prediction information generated by the intra-prediction unit (652) to the output sample information provided by the scaler / inverse transform unit (651) on a per-sample basis.

[0067] In other cases, the output samples of the scaler / inverse transform unit (651) may belong to inter-frame coded and potentially motion compensated blocks. In this case, the motion compensated prediction unit (653) may access the reference picture memory (657) to extract samples for prediction. After the extracted samples are motion compensated according to the symbols (621), these samples may be added to the output of the scaler / inverse transform unit (651) (in this case referred to as residual samples or residual signals) by the aggregator (655) to generate output sample information. The acquisition of prediction samples by the motion compensated prediction unit (653) from the address in the reference picture memory (657) may be controlled by a motion vector, and the motion vector is provided to the motion compensated prediction unit (653) in the form of the symbols (621), for example, including X, Y and reference picture components. Motion compensation may also include interpolation of sample values ​​extracted from the reference picture memory (657) when using sub-sample accurate motion vectors, motion vector prediction mechanisms, and the like.

[0068] The output samples of the aggregator (655) may be employed by various loop filtering techniques in a loop filter unit (656). The video compression techniques may include in-loop filter techniques controlled by parameters included in the encoded video sequence (also referred to as the encoded video bitstream) and available to the loop filter unit (656) as symbols (621) from the parser (620). However, in other embodiments, the video compression techniques may also be responsive to meta-information obtained during decoding of a previous (in decoding order) portion of an encoded picture or encoded video sequence, as well as to previously reconstructed and loop filtered sample values.

[0069] The output of the loop filter unit (656) may be a sample stream that may be output to a display device (612) and stored in a reference picture memory (657) for subsequent inter-picture prediction.

[0070] Once fully reconstructed, certain coded pictures may 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 (620)), the current picture buffer (658) may become part of the reference picture memory (657), and a new current picture buffer may be reallocated before starting to reconstruct a subsequent coded picture.

[0071] The video decoder (610) may perform decoding operations according to a predetermined video compression technique, such as in the ITU-T H.265 standard. The encoded video sequence may conform to the syntax specified by the video compression technique or standard used, in the sense that the encoded video sequence follows the syntax of the video compression technique or standard and the profile recorded in the video compression technique or standard. Specifically, the profile may select certain tools from all the tools available in the video compression technique 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 technique or standard. In some cases, the hierarchy limits the maximum picture size, the maximum frame rate, the maximum reconstruction sampling rate (measured in, for example, mega samples per second), the maximum reference picture size, etc. In some cases, the limits set by the hierarchy may be further limited by the Hypothetical Reference Decoder (HRD) specification and metadata of the HRD buffer management signaled in the encoded video sequence.

[0072] In an embodiment, the receiver (631) 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 (610) 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, etc.

[0073] Figure 7 7 is a block diagram of a video encoder (703) according to an embodiment disclosed in the present application. The video encoder (703) is provided in an electronic device (720). The electronic device (720) includes a transmitter (740) (e.g., a transmission circuit). The video encoder (703) can be used to replace Figure 5 A video encoder (503) in an embodiment.

[0074] The video encoder (703) can be used to obtain the video source (701) (not Figure 7 In another embodiment, the video source (701) is a part of the electronic device (720) to receive video samples, and the video source can collect video images to be encoded by the video encoder (703). In another embodiment, the video source (701) is a part of the electronic device (720).

[0075] The video source (701) may provide a source video sequence in the form of a digital video sample stream to be encoded by the video encoder (703), wherein the digital video sample stream 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 service system, the video source (701) may be a storage device storing previously prepared videos. In a video conferencing system, the video source (701) may be a camera that captures local image information as a video sequence. The video data may be provided as a plurality of separate pictures that are given motion when viewed sequentially. The pictures themselves may be constructed as a spatial pixel array, wherein each pixel may include one or more samples depending on the sampling structure, color space, etc. used. The relationship between pixels and samples may be easily understood by those skilled in the art. The following description focuses on samples.

[0076] According to an embodiment, the video encoder (703) may encode and compress pictures of a source video sequence into an encoded video sequence (743) in real time or under any other time constraints required by the application. Implementing an appropriate encoding speed is a function of the controller (750). In some embodiments, the controller (750) controls other functional units as described below and is functionally coupled to these units. For the sake of simplicity, couplings are not shown in the figure. The parameters set by the controller (750) 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 (750) can be used to have other suitable functions that are related to the video encoder (703) optimized for a certain system design.

[0077] In some embodiments, the video encoder (703) operates in a coding loop. As a simple description, in embodiments, the coding loop may include a source encoder (730) (e.g., responsible for creating symbols, such as a symbol stream, based on an input picture to be encoded and a reference picture) and a (local) decoder (733) embedded in the video encoder (703). The decoder (733) reconstructs the symbols to create sample data in a manner similar to that of the (remote) decoder to create 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 (734). Since the decoding of the symbol stream produces bit-accurate results that are independent of the decoder location (local or remote), the contents of the reference picture memory (734) 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 drift that occurs when synchronization cannot be maintained, eg due to channel errors) is also used in some related techniques.

[0078] The operation of the "local" decoder (733) can be combined with the above Figure 6 The "remote" decoder described in detail for the video decoder (610) is identical. However, additional brief reference is made to Figure 6 , when symbols are available and the entropy encoder (745) and parser (620) are capable of losslessly encoding / decoding the symbols into an encoded video sequence, the entropy decoding portion of the video decoder (610), including the buffer memory (615) and the parser (620), may not be fully implemented in the local decoder (733).

[0079] At this point, it can be observed that any decoder technology other than the parsing / entropy decoding present in the decoder must also be present in the corresponding encoder in substantially the same functional form. For this reason, the present application focuses on decoder operation. The description of encoder technology can be simplified because encoder technology is mutually inverse to the decoder technology described comprehensively. A more detailed description is only needed in certain areas and is provided below.

[0080] During operation, in some embodiments, the source encoder (730) 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 from a video sequence designated as "reference pictures." In this manner, the encoding engine (732) 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.

[0081] The local video decoder (733) may decode the encoded video data of the picture that may be designated as the reference picture based on the symbol created by the source encoder (730). The operation of the encoding engine (732) may be a lossy process. When the encoded video data is available at the video decoder ( Figure 7 When the video sequence is 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 (733) replicates the decoding process that may be performed by the video decoder on the reference picture and may cause the reconstructed reference picture to be stored in the reference picture cache (734). In this way, the video encoder (703) 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.

[0082] The predictor (735) may perform a prediction search for the encoding engine (732). That is, for a new picture to be encoded, the predictor (735) may search the reference picture memory (734) for sample data (as candidate reference pixel blocks) or certain metadata, such as reference picture motion vectors, block shapes, etc., that may serve as appropriate prediction references for the new picture. The predictor (735) may operate pixel-by-pixel based on sample blocks to find a suitable prediction reference. In some cases, based on the search results obtained by the predictor (735), it may be determined that the input picture may have prediction references taken from a plurality of reference pictures stored in the reference picture memory (734).

[0083] The controller (750) may manage encoding operations of the source encoder (730), including, for example, setting parameters and subgroup parameters for encoding video data.

[0084] The outputs of all the above functional units may be entropy encoded in an entropy encoder (745). The entropy encoder (745) performs lossless compression on the symbols generated by the various functional units according to techniques such as Huffman coding, variable length coding, arithmetic coding, etc., thereby converting the symbols into a coded video sequence.

[0085] The transmitter (740) may buffer the encoded video sequence created by the entropy encoder (745) in preparation for transmission over a communication channel (760), which may be a hardware / software link to a storage device where the encoded video data will be stored. The transmitter (740) may combine the encoded video data from the video encoder (703) with other data to be transmitted, such as encoded audio data and / or ancillary data streams (source not shown).

[0086] The controller (750) may manage the operation of the video encoder (703). During encoding, the controller (750) may 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 may generally be assigned to any of the following picture types:

[0087] An intra picture (I picture) may be 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 pictures and their corresponding applications and features.

[0088] A predictive picture (P picture) may be a picture 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.

[0089] Bidirectional predictive pictures (B pictures), which can be pictures that can be encoded and decoded using intra prediction or inter 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 reconstruction of a single block.

[0090] The source picture may typically be 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, which are determined according to the coding allocation applied to the block's corresponding picture. For example, blocks of an I picture may be non-predictively coded, or the blocks may be predictively coded (spatial prediction or intra prediction) with reference to already coded blocks of the same picture. Blocks of pixels of a P picture may be predictively coded by spatial prediction with reference to one previously coded reference picture or by temporal prediction. Blocks of a B picture may be predictively coded by spatial prediction with reference to one or two previously coded reference pictures or by temporal prediction.

[0091] The video encoder (703) may perform encoding operations according to a predetermined video encoding technique or standard, such as ITU-T H.265 Recommendation. In operation, the video encoder (703) may perform various compression operations, including predictive encoding operations that exploit temporal and spatial redundancy in an input video sequence. Thus, the encoded video data may conform to the syntax specified by the video encoding technique or standard used.

[0092] In an embodiment, the transmitter (740) may transmit additional data when transmitting the encoded video. The source encoder (730) may include such data as part of the encoded video sequence. The additional data may include other forms of redundant data such as temporal / spatial / SNR enhancement layers, redundant pictures and slices, SEI messages, VUI parameter set fragments, etc.

[0093] The captured video may be taken as a plurality of source pictures (video pictures) in a temporal sequence. Intra-picture prediction (often simplified to intra-prediction) exploits spatial correlations in a given picture, while inter-picture prediction exploits (temporal or other) correlations between pictures. In an embodiment, a particular picture being encoded / decoded is partitioned 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 reference picture that was previously encoded in the video and is still buffered, the block in the current picture may be encoded by a vector called a motion vector. The motion vector points to a reference block in a reference picture, and in the case where multiple reference pictures are used, the motion vector may have a third dimension that identifies the reference picture.

[0094] In some embodiments, bidirectional prediction techniques may be used in inter-picture prediction. According to the bidirectional prediction technique, two reference pictures are used, for example, a first reference picture and a second reference picture that are both before the current picture in the video in decoding order (but may be in the past and future in display order, respectively). A block in the current picture may be encoded by 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 may be predicted by a combination of the first reference block and the second reference block.

[0095] In addition, merge mode technology can be used in inter-picture prediction to improve coding efficiency.

[0096] According to some embodiments disclosed in the present application, predictions such as inter-picture prediction and intra-picture prediction are performed in 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. In general, 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 4 32×32 pixel CUs, or 16 16×16 pixel CUs. In an embodiment, each CU is analyzed to determine the prediction type 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 luminance prediction block (PB) and two chrominance PBs. In an embodiment, the prediction operation in encoding (encoding / decoding) is performed in units of prediction blocks. Taking the luminance prediction block as an example of a prediction block, the prediction block includes a matrix of pixel values ​​(e.g., luminance values), such as 8×8 pixels, 16×16 pixels, 8×16 pixels, 16×8 pixels, and the like.

[0097] Figure 8 1 is a diagram of a video encoder (803) according to another embodiment disclosed in the present application. The video encoder (803) is used to receive a processed block (e.g., a prediction block) of sample values ​​in a current video picture in a video picture sequence, and encode the processed block into an encoded picture that is part of an encoded video sequence. In this embodiment, the video encoder (803) is used to replace Figure 5A video encoder (503) in an embodiment.

[0098] In an HEVC embodiment, a video encoder (803) receives a matrix of sample values ​​for a processing block, such as a prediction block of 8×8 samples. The video encoder (803) uses, for example, rate-distortion optimization to determine whether to use intra mode, inter mode, or bidirectional prediction mode to encode the processing block. When encoding the processing block in intra mode, the video encoder (803) may use intra prediction techniques to encode the processing block into an encoded picture; and when encoding the processing block in inter mode or bidirectional prediction mode, the video encoder (803) may use inter prediction or bidirectional prediction techniques to encode the processing block into an encoded picture, respectively. In some video encoding 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 the aid of an encoded motion vector component external to the predictor. In some other video encoding techniques, there may be a motion vector component applicable to the subject block. In an embodiment, the video encoder (803) includes other components, such as a mode decision module (not shown) for determining the processing block mode.

[0099] exist Figure 8 In an embodiment of the present invention, the video encoder (803) includes: Figure 8 Shown are an inter-frame encoder (830), an intra-frame encoder (822), a residual calculator (823), a switch (826), a residual encoder (824), a common controller (821), and an entropy encoder (825) coupled together.

[0100] The inter-frame encoder (830) 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 according to an inter-frame coding technique, motion vectors, merge mode information), and calculate an inter-frame prediction result (e.g., a predicted block) based on the inter-frame prediction information using any suitable technique. In some embodiments, the reference picture is a decoded reference picture decoded based on the encoded video information.

[0101] The intra-frame encoder (822) is used to receive samples of a current block (e.g., a processing block), compare the block with an encoded block in the same picture in some cases, generate quantization 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). In an embodiment, the intra-frame encoder (822) also calculates an intra-frame prediction result (e.g., a predicted block) based on the intra-frame prediction information and a reference block in the same picture.

[0102] The general controller (821) is used to determine the general control data and control other components of the video encoder (803) based on the general control data. In an embodiment, the general controller (821) determines the mode of the block and provides a control signal to the switch (826) based on the mode. For example, when the mode is intra mode, the general controller (821) controls the switch (826) to select the intra mode result for use by the residual calculator (823) and controls the entropy encoder (825) to select the intra prediction information and add the intra prediction information to the bitstream; and when the mode is inter mode, the general controller (821) controls the switch (826) to select the inter prediction result for use by the residual calculator (823) and controls the entropy encoder (825) to select the inter prediction information and add the inter prediction information to the bitstream.

[0103] The residual calculator (823) is used to calculate the difference (residual data) between the received block and the prediction result selected from the intra-frame encoder (822) or the inter-frame encoder (830). The residual encoder (824) is used to operate based on the residual data to encode the residual data to generate a transform coefficient. In an embodiment, the residual encoder (824) is used to convert the residual data from the time domain to the frequency domain and generate a transform coefficient. The transform coefficient is then processed by quantization to obtain a quantized transform coefficient. In various embodiments, the video encoder (803) also includes a residual decoder (828). The residual decoder (828) is used to perform an inverse transform and generate decoded residual data. The decoded residual data can be used appropriately by the intra-frame encoder (822) and the inter-frame encoder (830). For example, the inter-frame encoder (830) can generate a decoded block based on the decoded residual data and the inter-frame prediction information, and the intra-frame encoder (822) can generate a decoded block based on the decoded residual data and the intra-frame prediction information. The decoded blocks are appropriately processed to generate a decoded picture, and in some embodiments, the decoded picture may be buffered in a memory circuit (not shown) and used as a reference picture.

[0104] The entropy encoder (825) is used to format the code stream to produce an encoded block. The entropy encoder (825) generates various information according to a suitable standard such as the HEVC standard. In an embodiment, the entropy encoder (825) is used to obtain general control data, selected prediction information (such as intra-frame prediction information or inter-frame prediction information), residual information, and other suitable information in the code stream. It should be noted that according to the disclosed subject matter, when the block is encoded in the inter-frame mode or the merge sub-mode of the bidirectional prediction mode, there is no residual information.

[0105] Fig. 9FIG. 9 is a diagram of a video decoder (910) according to another embodiment disclosed in the present application. The video decoder (910) is used 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 (910) is used to replace Figure 5 A video decoder (510) of an embodiment.

[0106] exist Fig. 9 In one embodiment, the video decoder (910) includes: Fig. 9 An entropy decoder (971), an inter-frame decoder (980), a residual decoder (973), a reconstruction module (974) and an intra-frame decoder (972) coupled together are shown in FIG.

[0107] The entropy decoder (971) 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, a mode for encoding 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 (972) or the inter decoder (980), respectively, residual information in the form of, for example, quantized transform coefficients, and the like. In an embodiment, when the prediction mode is inter or bidirectional prediction mode, the inter prediction information is provided to the inter decoder (980); and when the prediction type is an intra prediction type, the intra prediction information is provided to the intra decoder (972). The residual information may be inverse quantized and provided to the residual decoder (973).

[0108] The inter-frame decoder (980) is used for receiving the inter-frame prediction information and generating an inter-frame prediction result based on the inter-frame prediction information.

[0109] The intra-frame decoder (972) is used to receive intra-frame prediction information and generate a prediction result based on the intra-frame prediction information.

[0110] The residual decoder (973) 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 (973) may also require some control information (to obtain the quantizer parameter QP), and this information can be provided by the entropy decoder (971) (the data path is not indicated because this is only low-volume control information).

[0111] The reconstruction module (974) is used to combine the residual output by the residual decoder (973) with the prediction result (which can be output by the inter-frame prediction module or the intra-frame prediction module) in the spatial domain to form a reconstructed block, which 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.

[0112] It should be noted that the video encoder (503), video encoder (703), and video encoder (803) and video decoder (510), video decoder (610), and video decoder (910) may be implemented using any suitable technology. In an embodiment, the video encoder (503), video encoder (703), and video encoder (803) and video decoder (510), video decoder (610), and video decoder (910) may be implemented using one or more integrated circuits. In another embodiment, the video encoder (503), video encoder (703), and video encoder (803) and video decoder (510), video decoder (610), and video decoder (910) may be implemented using one or more processors that execute software instructions.

[0113] Aspects of the present disclosure provide signaling techniques for a skip mode flag.

[0114] Block-based compensation can be used for inter-frame prediction and intra-frame prediction. For inter-frame prediction, block-based compensation based on different pictures is called motion compensation. For intra-frame prediction, block-based compensation can also be performed based on previously reconstructed areas within the same picture. Block-based compensation based on reconstructed areas within the same picture is called intra-frame block compensation, current picture reference (CPR) or intra-frame block copy (IBC). The displacement vector indicating the offset between the current block and the reference block in the same picture is called a block vector (or simply BV). The motion vector in motion compensation can be any value (positive or negative, in the x or y direction). Unlike the motion vector in motion compensation, the block vector has some constraints to ensure that the reference block is available and has been reconstructed. Moreover, in some examples, some reference areas that are block boundaries or wavefront ladder shape boundaries are excluded for parallel processing considerations.

[0115] The encoding and decoding of block vectors can be explicit or implicit. In explicit mode (or called Advanced Motion Vector Prediction (AMVP) mode in inter-frame codecs), the difference between the block vector and the predicted value of the block vector is signaled. In implicit mode, the block vector is recovered from the predicted value (called the block vector predictor) in a similar way to the motion vector in merge mode. In some embodiments, the resolution of the block vector is restricted to integer positions; in other systems, the block vector is allowed to point to fractional positions.

[0116] In some examples, a block level flag called an IBC flag may be used to signal the use of intra block copying at the block level. In an embodiment, the IBC flag is signaled when the current block is not encoded in merge mode. In other examples, the use of intra block copying at the block level is signaled by reference indexing. The current picture in decoding is then considered as a reference picture. In an example, such a reference picture is placed at the last position of the reference picture list. This special reference picture is also managed with other temporal reference pictures in a buffer. The buffer is, for example, a decoded picture buffer (DPB).

[0117] There are also some variations of intra block copying, such as flipped intra block copying (flipping the reference block horizontally or vertically before being used to predict the current block) or row-based intra block copying (each compensation unit within an M×N codec block is an M×1 or 1×N row).

[0118] Fig.10 An example of intra-block copying according to an embodiment of the present disclosure is shown. The current picture (1000) is being decoded. The current picture (1000) includes a reconstruction area (1010) (a dot area) and an area to be decoded (1020) (a white area). The current block (1030) is being reconstructed by the decoder. The current block (1030) can be reconstructed from a reference block (1040) in the reconstruction area (1010). The position offset between the reference block (1040) and the current block (1030) is called a block vector (1050) (or BV (1050)).

[0119] In some examples, intra block copy may be considered a separate mode from intra prediction mode or inter prediction mode, and signaling of intra block copy may be specified at the block level using a combination of flags (eg, pred_mode_ibc_flag and pred_mode_flag).

[0120] In a related example, the codec block may be encoded in an intra prediction mode or an inter prediction mode. In a related example, a prediction mode flag "pred_mode_flag" having one bit may be signaled or inferred at the codec block level to distinguish the codec mode of the current block. For example, if pred_mode_flag is equal to 0, MODE_INTER (inter prediction mode) is used; otherwise (pred_mode_flag is equal to 1), MODE_INTRA (intra prediction mode) is used.

[0121] When intra block copy is used, the mode decision may be determined based on the values ​​of both pred_mode_flag and pred_mode_ibc_flag.

[0122] In some examples (e.g., one version of VVC), the maximum block size of an inter-coded CU can be up to 128×128; the maximum block size of an intra-coded CU can be up to 128×128; the maximum block size of an intra-block-copy coded CU can be up to 64×64, all of which are the sizes on luma coded samples. When using separate luma / chroma coding trees, the maximum possible chroma CU size in a 4:2:0 color format will be 32×32.

[0123] In some examples, for blocks that are inter-coded (coded using an inter-frame prediction mode) or IBC-coded (coded using an IBC mode), motion parameters may be predicted, for example, in a merge mode or a skip mode. In merge mode, the video encoder uses motion parameters from neighboring blocks as candidates to construct a candidate list of motion parameters (e.g., reference pictures and motion vectors). Neighboring blocks include spatial neighboring blocks and temporal neighboring blocks. The selected motion parameters may be signaled from the video encoder to the video decoder by transmitting an index of the selected candidate from the candidate list. At the video decoder, once the index is decoded, the motion parameters of the corresponding block of the selected candidate may be inherited. The video encoder and the video decoder are configured to construct the same list based on the coded blocks. Thus, based on the index, the video decoder may identify the motion parameters of the candidate selected by the video encoder.

[0124] In skip mode, motion parameters may be predicted similarly to in merge mode. Furthermore, in skip mode, no residual data is added to the prediction block, whereas in merge mode, residual data is added to the prediction block. The construction of the list and the transmission of indices for identifying candidates in the list described above with reference to merge mode are typically also performed in skip mode. In some embodiments, a skip flag in the codec block level may be used to indicate whether a block is encoded using skip mode.

[0125] Fig.11An exemplary syntax table (1100) for signaling prediction mode at the codec unit (or codec block) level is shown. The syntax table (1100) conditionally extracts three flags cu_skip_flag, pred_mode_flag, and pred_mode_ibc_flag from the coded video bitstream, such as Fig.11 As shown in (1101), (1102) and (1103) in .

[0126] Specifically, cu_skip_flag[x0][y0] is a skip flag. The skip flag cu_skip_flag[x0][y0] equal to 1 specifies that the current codec unit is encoded in skip mode. Therefore, when the current codec unit is in a P (coded by inter-frame prediction) slice or a B (coded by bidirectional inter-frame prediction) slice, no syntax elements other than one or more of the following are parsed after cu_skip_flag[x0][y0]: IBC mode flag pred_mode_ibc_flag[x0][y0] and merge_data() syntax structure. When the current codec unit is in an I slice, no syntax elements other than merge_idx[x0][y0] are parsed after cu_skip_flag[x0][y0]. Here, a slice, for example (also referred to as a slice), can be the largest decoding unit of an image, and the types of slices can include I slices, P slices, and B slices. An I slice can represent a slice of an I frame image (intra picture).

[0127] The skip flag cu_skip_flag[x0][y0] equal to 0 specifies that the codec unit is not in skip mode. The array index x0, y0 specifies the position (x0, y0) of the top left luma sample of the considered codec block relative to the top left luma sample of the picture.

[0128] When cu_skip_flag[x0][y0] is not present in the encoded video stream, cu_skip_flag[x0][y0] may be inferred to be equal to 0.

[0129] Furthermore, pred_mode_flag equal to 0 specifies that the current codec unit is encoded in inter-prediction mode; and pred_mode_flag equal to 1 specifies that the current codec unit is encoded in intra-prediction mode.

[0130] In some embodiments, pred_mode_flag is not present in the encoded video bitstream and pred_mode_flag can be inferred. The inference of pred_mode_flag can be based on the variable modeType. In general, the variable modeType specifies whether the intra prediction mode (MODE_INTRA), IBC mode (MODE_IBC), palette mode (MODE_PLT) and inter prediction mode (MODE_TYPE_ALL) can be used for the codec unit in the coding tree node, or whether only the intra, IBC and palette codec modes (MODE_TYPE_INTRA) can be used, or whether only the inter codec mode (MODE_TYPE_INTER) can be used. For example, when the variable modeType is MODE_TYPE_ALL, all modes of the intra prediction mode, IBC mode, palette mode and inter prediction mode can be used; when the variable modeType is MODE_TYPE_INTRA, the intra prediction mode, IBC mode and palette mode can be used; when the variable modeType is MODE_TYPE_INTER, only the inter prediction mode can be used.

[0131] In some examples, the variable modeType is used to control the prediction mode types that may be allowed for certain smaller CU sizes. At the CTU root (where the coding_tree() syntax is first called), the value of this variable is set to MODE_TYPE_ALL (meaning unconstrained). Therefore, for larger CUs, such as 128×128, 128×64, 64×128, modeType should be set to MODE_TYPE_ALL. When a larger CU is split into smaller CUs, the variable modeType of the smaller CU can be modified, for example, based on the variable treeType. In an embodiment, the coding tree scheme supports the ability of the luma component and the corresponding chroma component to have separate block tree structures. In the example, for P slices and B slices, the luma CTB and chroma CTB in the CTU share the same coding tree structure (e.g., a single tree). For I slices, the luma CTB and chroma CTB in the CTU can have separate block tree structures (e.g., dual trees), and the partitioning of the CTU using separate block tree structures is called dual tree partitioning. When dual-tree partitioning is applied, the luma CTB can be partitioned into luma CUs by a luma coding tree structure (e.g., DUAL_TREE_LUMA), and the chroma CTB can be partitioned into chroma CUs by a chroma coding tree structure (e.g., DUAL_TREE_CHROMA). Therefore, a CU in an I slice may include a codec block for a luma component and may include codec blocks for two chroma components, and a CU in a P or B slice includes codec blocks for all three color components unless the video is monochrome. In the example, the variable treeType specifies whether the codec unit partitioned from the coding tree unit uses a single tree (SINGLE_TREE) or a dual tree; when using a dual tree, the variable treeType specifies whether a luma component (DUAL_TREE_LUMA) or a chroma component (DUAL_TREE_CHROMA) is currently being processed.

[0132] In some embodiments, pre_mode_flag may be inferred as follows:

[0133] - if cbWidth (the width of the codec unit) is equal to 4 and cbHeight (the height of the codec unit) is equal to 4, then for some exemplary reasons, inter prediction mode is not applied to 4×4 blocks and pred_mode_flag is inferred to be equal to 1;

[0134] - Otherwise, if modeType is equal to MODE_TYPE_INTRA, pred_mode_flag is inferred to be equal to 1;

[0135] - Otherwise, if modeType is equal to MODE_TYPE_INTER, pred_mode_flag is inferred to be equal to 0;

[0136] - Otherwise, pred_mode_flag is inferred to be equal to 1 when decoding an I slice and equal to 0 when decoding a P or B slice, respectively.

[0137] The variable CuPredMode[chType][x][y] is the following prediction mode derived for x=x0..x0+cbWidth?1 and y=y0..y0+cbHeight?1:

[0138] - If pred_mode_flag is equal to 0, CuPredMode[chType][x][y] is set equal to MODE_INTER (inter prediction mode);

[0139] - Otherwise (pred_mode_flag is equal to 1), CuPredMode[chType][x][y] is set equal to MODE_INTRA (inter-frame prediction mode).

[0140] Furthermore, the flag pred_mode_ibc_flag equal to 1 specifies that the current codec unit is coded in IBC mode. The flag pred_mode_ibc_flag equal to 0 specifies that the current codec unit is not coded in IBC mode.

[0141] In some embodiments, pred_mode_ibc_flag is not present in the encoded bitstream and may be inferred. The inference of pred_mode_ibc_flag may be based on the variables modeType and treeType.

[0142] For example, pred_mode_ibc_flag can be inferred as follows:

[0143] - If cu_skip_flag[x0][y0] is equal to 1, and cbWidth is equal to 4, and cbHeight is equal to 4,

[0144] It is inferred that pred_mode_ibc_flag is equal to 1;

[0145] - Otherwise, if cbWidth or cbHeight is equal to 128, pred_mode_ibc_flag is inferred to be equal to 0;

[0146] - Otherwise, if modeType is equal to MODE_TYPE_INTER, pred_mode_ibc_flag is inferred to be equal to 0;

[0147] - Otherwise, if treeType is equal to DUAL_TREE_CHROMA, pred_mode_ibc_flag is inferred to be equal to 0;

[0148] - Otherwise, pred_mode_ibc_flag is inferred to be equal to the value of sps_ibc_enabled_flag when decoding I slices, and pred_mode_ibc_flag is inferred to be equal to 0 when decoding P or B slices.

[0149] When pred_mode_ibc_flag is equal to 1, for x=x0..x0+cbWidth-1 and y=y0..y0+cbHeight-1, the variable CuPredMode[chType][x][y] is set equal to MODE_IBC.

[0150] FIG. 12A to FIG. 12E An exemplary syntax table (1200) for the coding tree unit level is shown. In this example, the input parameter modeTypeCurr is the modeType variable inherited from its parent node.

[0151] It should be noted that in some examples, such as Fig.11 The syntax and semantics in the syntax in do not correctly reflect the block size constraints applied in intra / inter / IBC modes. For example, Fig.11 The condition (1110) in is equivalent to performing a logical OR (||) of the first condition (!(cbWidth==4&&cbHeight==4)&&(modeType!==MODE_TYPE_INTRA)) and the second condition (sps_ibc_enabled_flag). The first condition checks whether the logical value of (!(cbWidth==4&&cbHeight==4)&&(modeType!==MODE_TYPE_INTRA)) is 1 or 0. The second condition checks whether the logical value of (sps_ibc_enabled_flag) is 1 or 0. The first condition with a value of 1 specifies that the current block in the encoding is an inter-frame coded block. The second condition with a value of 1 specifies that the IBC mode is started. Fig.11In the example of , when at least one of the first condition and the second condition is equal to 1 and treeType is not equal to DUAL_TREE_CHROMA, the skip flag (e.g., cu_skip_flag[x0][y0]) appears in the coded video bitstream and can be decoded. However, in the example, the codec unit in the I slice may have at least one dimension (width and / or height) greater than 64. The parameters of the codec unit may be such that the first condition is 1 and / or the second condition is 1. However, the codec unit cannot perform inter-frame coding (due to being in an I slice) and cannot perform IBC coding (due to at least one dimension being greater than 64). Therefore, condition (1110) cannot correctly reflect the block size constraints applied in intra / inter / IBC mode.

[0152] Some aspects of the present disclosure provide techniques for correctly reflecting the block size constraints applied in intra / inter / IBC modes. The following description is based on the assumption that intra block copy (IBC) mode is considered a separate mode different from intra mode or inter mode. These techniques can signal a skip flag (e.g., cu_skip_flag[x0][y0]) only when IBC mode is possible in an I slice. If only intra mode is possible, there is no need to signal the skip flag; instead, the skip flag can be inferred to be 0.

[0153] In an embodiment, additional conditions may be imposed on the signaling of the skip flag, so that when the CU block size indicates that only intra mode is possible (block size exceeds the maximum IBC block size), the skip flag is not signaled (not present in the coded video bitstream). Instead, the skip flag may be inferred to be 0.

[0154] In an example, when a block in an I slice is larger than 64 luma samples on either the width or height side, the block cannot be inter coded and cannot be IBC coded, and thus only intra mode (intra prediction mode) is available for the block.

[0155] Fig.13 An exemplary syntax table (1300) according to some embodiments of the present disclosure is shown. Fig.13 As shown in (1310) in , a third condition (!(slice_type=I&&(cbWidth>64||cbHeight>64))) is added to combine with the first and second conditions (using the logical AND operator &&). The third condition can be 0 when the block in the I slice is greater than 64 luma samples on the width side or the height side. Then, the combination of the first, second and third conditions is equal to 0. Therefore, the skip flag (cu_skip_flag[x0][y0]) is not signaled (does not appear in the encoded video bitstream).

[0156] In another embodiment, the first condition and / or the second condition may be appropriately modified to apply the size restrictions of the IBC mode. In some examples, the assignment of modeType is modified so that when the CU block size indicates that only intra mode is possible in the I slice (the block size exceeds the maximum IBC block size), modeType is set to MODE_TYPE_INTRA which may cause the first condition to be equal to 0. In some embodiments, if (slice_type == I && (cbWidth>64||cbHeight>64)) holds, modeType is set to MODE_TYPE_INTRA.

[0157] Fig.14 An exemplary syntax table (1400) for a coding tree level according to some embodiments of the present disclosure is shown. As shown in (1410), when a block in an I slice is larger than 64 luma samples on either the width side or the height side, the variable modeTypeCurrr is set to MODE_TYPE_INTRA. The variable modeTypeCurr is Fig.14 and Fig.13 . Therefore, in the coding_unit() syntax table, the result of the first condition is 0. In another example, in the coding_unit() syntax, when a block in an I slice is greater than 64 luma samples on either the width side or the height side, the variable modeType is set to MODE_TYPE_INTRA before the first "if" clause. Therefore, the result of the first condition is 0.

[0158] In some examples, the second condition may be modified to apply the size limit of the IBC mode. For example, the second condition is modified to (sps_ibc_enabled_flag&&cbWidth<=64&&cbHeight<=64). Therefore, when a block in an I slice is larger than 64 luma samples on the width side or the height side, the result of the second condition is 0.

[0159] It should be noted that the embodiments in the present disclosure can be used alone or in combination in any order.

[0160] Fig.15A flow chart outlining a method (1500) according to an embodiment of the present disclosure is shown. The method (1500) may be used for reconstruction of a block, thereby generating a prediction block for the block under reconstruction. In various embodiments, the method (1500) is performed by a processing circuit, such as a processing circuit in a terminal device (410), (420), (430) and (440), a processing circuit that performs the functions of a video encoder (503), a processing circuit that performs the functions of a video decoder (510), a processing circuit that performs the functions of a video decoder (610), a processing circuit that performs the functions of a video encoder (703), and the like. In some embodiments, the method (1500) is implemented in software instructions, so that when the processing circuit executes the software instructions, the processing circuit performs the method (1500). The method starts at (S1501) and proceeds to (S1510).

[0161] In (S1510), prediction information of blocks in an I slice is decoded from the encoded video bitstream.

[0162] In (S1520), based on the prediction information and the size limit of the IBC mode, it is determined whether the IBC mode is available for the block. In some embodiments, in response to the size of the block being greater than a size threshold of the IBC mode, it is determined that the IBC mode is available for the block in the I slice. In one embodiment, when at least one of the width or height of the block is greater than the size threshold of the IBC mode, it is determined that the IBC mode is available for the block.

[0163] In some embodiments, (S1520) the current mode type parameter is set to an intra coding mode in response to the slice type parameter indicating an I slice and at least one of the width or height of the block being greater than 64. For example, the intra coding mode is indicated by an identifier MODE_TYPE_INTRA.

[0164] In some embodiments, the possibility that a block in an I slice is in IBC mode determines whether a skip flag (skip mode flag) for the block is in the coded video bitstream. In some examples, the grammar includes some existing conditions to determine the presence of a skip flag. In one embodiment, the presence of the skip flag in the coded video bitstream is also determined based on an added condition. The added condition is to compare the size of the block with a size threshold. The presence of the skip flag in the coded video bitstream is excluded in response to the size of the block in the I slice being greater than the threshold.

[0165] In another embodiment, the presence of the flag in the coded video bitstream is determined based on an existing condition modified to compare the size of the block to a size threshold of the IBC mode. In one example, the existing condition is a first condition for determining whether the block is an inter-coded block, and the first condition is modified based on the comparison of the size of the block to the threshold. In another example, the existing condition is a second condition for determining whether the IBC mode is enabled, and the second condition is modified based on the comparison of the size of the block to the threshold.

[0166] In (S1530), in some examples, in response to the block in the I slice being in IBC mode, a skip flag indicating whether the skip mode is applied to the block is decoded from the encoded video bitstream. In addition, in some examples, in response to the IBC mode being unavailable for the block in the I slice, the skip flag is inferred.

[0167] In (S1540), the block is reconstructed based at least in part on the skip flag. In an example, when the skip flag indicates a skip mode, the block is reconstructed based on the skip mode. The method then proceeds to (S1599) and ends.

[0168] The above techniques may be implemented as computer software via computer-readable instructions and physically stored in one or more computer-readable media. Fig.16 A computer system (1600) is shown that is suitable for implementing certain embodiments of the disclosed subject matter.

[0169] The computer software may be encoded in any suitable machine code or computer language, and may be assembled, compiled, linked, or the like to create a code comprising instructions, which may be directly executed by one or more computer central processing units (CPUs), graphics processing units (GPUs), etc., or executed by decoding, microcode, or the like.

[0170] 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, etc.

[0171] Fig.16 The components shown for the computer system (1600) are exemplary in nature and are not intended to limit the scope of use or functionality of computer software implementing the embodiments of the present application. The configuration of the components should not be interpreted as having any dependency or requirement on any component or combination of components shown in the exemplary embodiment of the computer system (1600).

[0172] The computer system (1600) may include certain human-computer interface input devices. Such human-computer interface input devices may respond to input from one or more human users through tactile input (e.g., keyboard input, sliding, 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 human conscious input, such as audio (e.g., speech, music, ambient sound), images (e.g., scanned images, photographic images obtained from a still image camera), and videos (e.g., two-dimensional video, three-dimensional video including stereoscopic video).

[0173] The human-computer interface input device may include one or more of the following (only one of which is drawn): keyboard (1601), mouse (1602), touchpad (1603), touch screen (1610), data gloves (not shown), joystick (1605), microphone (1606), scanner (1607), camera (1608).

[0174] The computer system (1600) may also include certain human-computer interface output devices. Such human-computer interface output devices may stimulate one or more human user senses through, for example, tactile output, sound, light, and smell / taste. Such human-computer interface output devices may include tactile output devices (e.g., tactile feedback through a touch screen (1610), a data glove (not shown), or a joystick (1605), but there may also be tactile feedback devices that are not used as input devices), audio output devices (e.g., speakers (1609), headphones (not shown)), visual output devices (e.g., screens (1610) including cathode ray tube screens, liquid crystal screens, plasma screens, organic light emitting diode screens, each of which has or does not have a touch screen input function, each of which has or does not have a tactile feedback function - some of which can output two-dimensional visual output or output of more than three dimensions through means such as stereoscopic picture output; virtual reality glasses (not shown), holographic displays, and smoke boxes (not shown)) and printers (not shown).

[0175] The computer system (1600) may also include human-accessible storage devices and their associated media, such as optical media including high-density read-only / rewritable optical disks (CD / DVD ROM / RW) (1620) with CD / DVD or similar media (1621), thumb drives (1622), removable hard disk drives or solid state drives (1623), traditional magnetic media such as tapes and floppy disks (not shown), special-purpose ROM / ASIC / PLD-based devices such as security software protectors (not shown), and the like.

[0176] Those skilled in the art should also understand that the term "computer-readable media" used in connection with the disclosed subject matter does not include transmission media, carrier waves, or other transient signals.

[0177] The computer system (1600) 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. The network also includes 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 for connecting to some universal data ports or peripheral buses (1649) (e.g., a USB port of the computer system (1600)); other systems are typically integrated into the core of the computer system (1600) 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 smart phone computer system). By using any of these networks, the computer system (1600) 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., 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.

[0178] The above-mentioned human-machine interface devices, human-accessible storage devices, and network interfaces may be connected to the core (1640) of the computer system (1600).

[0179] The core (1640) may include one or more central processing units (CPUs) (1641), graphics processing units (GPUs) (1642), dedicated programmable processing units in the form of field programmable gate arrays (FPGAs) (1643), hardware accelerators for specific tasks (1644), etc. These devices, as well as read-only memory (ROM) (1645), random access memory (1646), internal mass storage (e.g., internal non-user accessible hard disk drives, solid-state drives, etc.) (1647), etc., may be connected via a system bus (1648). In some computer systems, the system bus (1648) may be accessed in the form of one or more physical plugs so that it may be expanded by additional central processing units, graphics processing units, etc. Peripheral devices may be directly attached to the core's system bus (1648), or connected via a peripheral bus (1649). The architecture of the peripheral bus includes PCI, USB, etc.

[0180] The CPU (1641), GPU (1642), FPGA (1643) and accelerator (1644) can execute certain instructions, which can be combined to form the above-mentioned computer code. The computer code can be stored in ROM (1645) or RAM (1646). Transition data can also be stored in RAM (1646), while permanent data can be stored in, for example, internal mass storage (1647). Fast storage and retrieval of any memory device can be achieved by using a cache memory, which can be closely associated with one or more CPUs (1641), GPUs (1642), mass storage (1647), ROM (1645), RAM (1646), etc.

[0181] The computer readable medium may have computer code thereon for performing various computer-implemented operations. The medium and computer code may be specially designed and constructed for the purpose of this application, or may be medium and code well known and available to those skilled in the art of computer software.

[0182] As an example and not a limitation, a computer system having an architecture (1600), in particular a core (1640), can provide the function of executing software contained in one or more tangible computer-readable media as a processor (including a CPU, a GPU, an FPGA, an accelerator, etc.). Such a computer-readable medium can be a medium associated with the above-mentioned user-accessible mass storage, as well as a specific memory of the core (1640) having non-volatility, such as a core internal mass storage (1647) or a ROM (1645). Software implementing various embodiments of the present application can be stored in such a device and executed by the core (1640). Depending on specific needs, the computer-readable medium may include one or more storage devices or chips. The software can enable the core (1640), in particular the processor therein (including a CPU, a GPU, an FPGA, etc.) to perform a specific process or a specific part of a specific process described herein, including defining a data structure stored in the RAM (1646) and modifying such a data structure according to a software-defined process. Additionally or alternatively, the computer system may provide functionality hardwired in logic or otherwise contained in circuitry (e.g., accelerator (1644)) that may operate in place of or in conjunction with software to perform a particular process or a particular portion of a particular process 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 application includes any suitable combination of hardware and software.

[0183] Appendix A: Acronyms

[0184] JEM: Joint Exploration Model

[0185] VVC: versatile video coding

[0186] BMS: Benchmark set

[0187] MV: Motion Vector

[0188] HEVC: High Efficiency Video Coding

[0189] SEI: Supplementary Enhancement Information

[0190] VUI: Video Usability Information

[0191] GOPs: Groups of Pictures

[0192] TUs: Transform Units

[0193] PUs: Prediction Units

[0194] CTUs: Coding Tree Units

[0195] CTBs: Coding Tree Blocks

[0196] PBs: Prediction Blocks

[0197] HRD: Hypothetical Reference Decoder

[0198] SNR: Signal Noise Ratio

[0199] CPUs: Central Processing Units

[0200] GPUs: Graphics Processing Units

[0201] CRT: Cathode Ray Tube

[0202] LCD: Liquid-Crystal Display

[0203] OLED: Organic Light-Emitting Diode

[0204] CD: Compact Disc

[0205] DVD: Digital Video Disc

[0206] ROM: Read-Only Memory

[0207] RAM: Random Access Memory

[0208] ASIC: Application-Specific Integrated Circuit

[0209] PLD: Programmable Logic Device

[0210] LAN: Local Area Network

[0211] GSM: Global System for Mobile communications

[0212] LTE: Long-Term Evolution

[0213] CANBus: Controller Area Network Bus

[0214] USB: Universal Serial Bus

[0215] PCI: Peripheral Component Interconnect

[0216] FPGA: Field Programmable Gate Areas

[0217] SSD: solid-state drive

[0218] IC:Integrated Circuit

[0219] CU: Coding Unit

[0220] Although the present application has described a number of exemplary embodiments, various changes, arrangements and various equivalent substitutions of the embodiments are within the scope of the present application. Therefore, it should be understood that those skilled in the art can design a variety of systems and methods, which, although not explicitly shown or described herein, embody the principles of the present application and are therefore within the spirit and scope of the present application.

Claims

1. A video encoding method, characterized in that: include: Receive blocks in an I slice from a video; Based on a slice type parameter indicating that the I slice corresponds to and at least one of a width and a height of the block is greater than 64, setting a current mode type parameter to an intra mode MODE_TYPE_INTRA; Determining whether a block in an I slice may use skip mode based on the width of the block being greater than 64 or the height being greater than 64 and at least one of the current mode type parameters; Based on the width and height of the block being both less than 64, or the current mode type parameter being not set to MODE_TYPE_INTRA, determining to encode a skip mode flag into a video bitstream of the block, wherein the skip mode flag indicates whether a skip mode is applied to the block; Based on the fact that the width or height of the block is greater than 64, or the current mode type parameter is MODE_TYPE_INTRA, it is determined not to encode the skip mode flag into the video bitstream of the block.

2. The method according to claim 1, characterized in that Based on the slice type parameter indicating the I slice, and the size of the block being greater than a threshold, and the current mode type parameter being set to MODE_TYPE_INTRA, it is determined that the skip mode flag is not signaled, and the skip mode flag value is set to 0.

3. The method according to claim 1, characterized in that Further including: Based on the block in the I slice not being able to use the intra-block-copy IBC mode, an IBC mode flag is inferred.

4. The method according to claim 1 or 3, characterized in that: Further including: In response to the size of the block in the I slice being greater than a threshold, it is determined that the block in the I slice cannot adopt the IBC mode.

5. The method according to any one of claims 4, characterized in that Further including: In response to at least one of the width and the height of the block being greater than a threshold, the block in the I slice may not be in IBC mode.

6. The method according to claim 4, characterized in that Further including: Based on an additional condition of comparing the size of the block with a threshold, determining to output the skip mode flag to the encoded video code stream of the block, the additional condition excluding the presence of the skip mode flag in response to the size of the block in the I slice being greater than the threshold.

7. The method according to claim 4, further comprising: Based on an existing condition modified to compare a size of a block with a threshold, it is determined that a skip mode flag is output to an encoded video bitstream of the block.

8. The method according to claim 7, wherein: The existing condition determines whether the block is an inter-coded block.

9. The method according to claim 7, wherein: The existing conditions determine whether the IBC mode is enabled.

10. A method for video decoding, characterized in that: include: Decode the prediction information of the blocks in the I slice from the encoded video bitstream; Based on determining that the width and height of the block are not greater than 64, or the current mode type parameter is not MODE_TYPE_INTRA, determining that a value of a skip mode flag indicates that a skip mode is applied to the block; Based on the width or height of the block being greater than 64, or the current mode type parameter being MODE_TYPE_INTRA, it is determined that the skip mode flag is not signaled in the encoded video stream.

11. A video encoding device, characterized in that: The method comprises a processing circuit configured to execute the encoding method according to any one of claims 1 to 9.

12. A video decoding device, characterized in that: The method comprises a processing circuit configured to perform the decoding method according to claim 10 .

13. A non-volatile computer-readable medium storing instructions, characterized in that: When the instructions are executed by a computer for video encoding and decoding, the computer is caused to execute: the method according to any one of claims 1-10.

14. A computer system, characterized in that: The computer system comprises: one or more computer readable non-volatile storage media configured to store computer program code; and One or more computer processors are configured to access the computer program code and operate according to the instructions of the computer program code to perform the method according to any one of claims 1 to 10.

15. A method for processing a video code stream, characterized in that: The video code stream is generated according to the encoding method according to any one of claims 1 to 9, or is decoded based on the decoding method according to claim 10.

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