Video processing method, device and storage medium

Abstract

Various aspects of the present disclosure provide video processing methods and devices. In some examples, the video processing device includes a processing circuit. The processing circuit determines one or more parameters of a time domain filter based on video content in an uncompressed video. The uncompressed video includes a frame sequence. Then, the processing circuit applies the time domain filter with the determined parameters to a first pixel in a first frame to determine a filter value of the first pixel based on the first pixel in the first frame and a second pixel in a set of reference frames of the first frame. In addition, the processing circuit encodes the filtered video to generate an encoded video bitstream carrying the filtered video, wherein the filtered video includes the filter value of the first pixel in the first frame.

Description

[0001] Incorporation by reference

[0002] This application claims the benefit of priority to U.S. Patent Application No. 17 / 446,080, entitled “METHOD AND APPARATUS FOR TEMPORALFILTER IN VIDEO CODING,” filed on August 26, 2021. The entire disclosure of that prior application is hereby incorporated by reference in its entirety. Technical Field

[0003] This disclosure describes embodiments generally related to temporal filtering in video coding. Background Art

[0004] The background description provided herein is for the purpose of generally presenting the context of the present disclosure. To the extent described in this background section, the work of the presently named inventors and aspects of the description that may not be prior art at the time of filing are neither explicitly nor implicitly admitted to be prior art to the present disclosure.

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

[0006] One purpose of video encoding and decoding is to reduce redundancy in the input video signal through compression. Compression helps reduce the bandwidth and / or storage space requirements mentioned above, in some cases by two orders of magnitude or more. Lossless compression and lossy compression and combinations thereof can be used. Lossless compression refers to techniques that can reconstruct an exact copy of the original signal from the compressed original signal. When lossy compression is used, the reconstructed signal may not be identical to the original signal, but the distortion between the original and the reconstructed signal is small enough that the reconstructed signal is useful for the intended application. In the case of video, lossy compression is widely used. The amount of distortion allowed depends on the application; for example, users of certain consumer streaming applications may tolerate higher distortion than users of television distribution applications. The achievable compression ratio can reflect that higher allowed / tolerable distortion can produce 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 a technique known as intra-coding. In intra-coding, sample values ​​are represented without reference to samples or other data from a previously reconstructed reference picture. In some video codecs, pictures are spatially subdivided into blocks of samples. When all sample blocks are encoded in intra-mode, the picture may be an intra-picture. Intra-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-blocks may be transformed, and transform coefficients may be quantized before entropy coding. Intra-prediction may be a technique for minimizing sample values ​​in a pre-transform domain. In some cases, the smaller the transformed DC value, the smaller the AC coefficient, and the fewer bits required to represent the entropy-coded block at a given quantization step size.

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

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

[0011] H.264 introduced specific intra prediction modes, improved in H.265, and further improved in newer coding techniques such as the joint exploration model (JEM), versatile video coding (VVC), and benchmark set (BMS). The prediction block can be formed using neighboring sample values ​​belonging to already available samples. Sample values ​​of neighboring samples are copied into the prediction block according to the direction. A reference to the direction in use can be encoded in the bitstream or can itself be predicted.

[0012] refer to Figure 1A , a subset of 9 known prediction directions of the 33 possible prediction directions of H.265 (corresponding to the 33 angular modes of the 35 intra modes) is depicted in the lower right. The point (101) where the arrows converge represents the sample being predicted. The arrows represent the direction of the predicted sample. For example, arrow (102) indicates that sample (101) is predicted from one or more samples at an angle of 45° to the upper right of the horizontal line. Similarly, arrow (103) indicates that sample (101) is predicted from one or more samples at an angle of 22.5° to the horizontal line and located to the lower left of sample (101).

[0013] Still reference Figure 1A , a square block (104) of 4×4 samples is depicted in the upper left (indicated by the thick dashed line). The square block (104) includes 16 samples, each sample labeled "S", its position in the Y dimension (e.g., row index) and its position in the X dimension (e.g., column index). For example, sample S21 is the second sample in the Y dimension (from the top) and the first sample in the X dimension (from the left). Similarly, sample S44 is the fourth sample in the block (104) in both the Y and X dimensions. Since the size of the block is 4×4 samples, S44 is located in the lower right corner. Reference samples are also shown following a similar numbering scheme. The reference samples are labeled with R, their Y position (e.g., row index) and X position (column index) relative to the block (104). In H.264 and H.265, the prediction samples are adjacent to the block being reconstructed; therefore, there is no need to use negative values.

[0014] Intra picture prediction can work by copying reference sample values ​​from neighboring samples, with the signaled prediction direction being appropriate. For example, assume that the coded video bitstream contains signaling that indicates a prediction direction consistent with arrow (102) for this block, i.e., predicting samples from one or more prediction samples to the upper right at a 45° angle to the horizontal. In this case, samples S41, S32, S23, and S14 are predicted from the same reference sample R05. Sample S44 is then predicted from reference sample R08.

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

[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 was increased to 33 in H.265 (2013), and JEM / VVC / BMS can support up to 65 directions at the time of disclosure. Experiments have been done to identify the most likely directions, and certain techniques in entropy coding are used to represent those possible directions with a small number of bits, accepting some penalty for less likely directions. Additionally, the direction itself can sometimes be predicted from adjacent directions used in adjacent already decoded blocks.

[0017] Figure 1B A schematic diagram (180) is shown depicting 65 intra prediction directions according to JEM to illustrate that the number of prediction directions increases over time.

[0018] The mapping of intra-prediction direction bits in the coded video bitstream that represent directions can vary depending on the video coding technique; and can range from simple direct mappings of, for example, prediction directions to intra-prediction modes, to codewords, to complex adaptive schemes involving most probable modes, and similar techniques. However, in all cases, some directions are statistically less likely to appear in the video content than some other directions. Since the goal of video compression is to reduce redundancy, in video coding techniques that work well, those less likely directions will be represented by more bits than more likely directions.

[0019] Motion compensation may be a lossy compression technique, and may involve techniques in which a block of sample data from a previously reconstructed picture or part thereof (reference picture) is used to predict a newly reconstructed picture or picture part after being spatially shifted in a direction indicated by a motion vector (hereafter MV). 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 being an indication of the reference picture in use (indirectly, the third dimension may be a temporal dimension).

[0020] In some video compression techniques, the MV applicable to a region of sample data can be predicted from other MVs, for example, from an MV related to another region of sample data that is spatially adjacent to the region being reconstructed and that precedes the MV in decoding order. Doing so can greatly reduce the amount of data required to encode the MV, thereby eliminating redundancy and improving compression. MV prediction can work effectively, for example, because when encoding an input video signal derived from a camera (called natural video), there is a statistical possibility that regions larger than the region to which a single MV can be applied move in similar directions, so in some cases, similar motion vectors derived from MVs of adjacent regions can be used for prediction. This results in the MV found for a given region being similar or identical to the MV predicted from the surrounding MVs, and after entropy coding, this can in turn be represented with fewer bits than would be used when encoding the MV directly. 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, MV prediction itself may be lossy, for example, due to losses caused by rounding errors when calculating predicted values ​​from several surrounding MVs.

[0021] Various MV prediction mechanisms are described in H.265 / HEVC (ITU-T Rec. H.265, "High Efficiency Video Coding", December 2016). From the many MV prediction mechanisms provided by H.265, a technique referred to as "spatial merging" is described here.

[0022] refer to Figure 2, the current block (201) includes samples that the encoder found during motion search to be predictable from a previous block of the same size that has been spatially shifted. The MV associated with any of the five surrounding samples (denoted A0, A1 and B0, B1, B2 (202 to 206, respectively)) can be derived from metadata associated with one or more reference pictures, for example, from the most recent (in decoding order) reference picture, rather than encoding the MV directly. In H.265, MV prediction can use a predictor from the same reference picture that a neighboring block is using. Summary of the invention

[0023] Various aspects of the present disclosure provide video processing methods and devices. In some examples, the video processing device includes a processing circuit. The processing circuit determines one or more parameters of a time domain filter based on video content in an uncompressed video. The uncompressed video includes a sequence of frames. Then, the processing circuit applies the time domain filter with the determined parameters to a first pixel in a first frame to determine a filter value of the first pixel based on the first pixel in the first frame and a second pixel in a set of reference frames of the first frame. In addition, the processing circuit encodes the filtered video to generate an encoded video bitstream carrying the filtered video, wherein the filtered video includes the filter value of the first pixel in the first frame. The first frame is a frame to be subjected to time domain filtering, and the first pixel is a pixel to be subjected to time domain filtering.

[0024] In some examples, the one or more parameters of the temporal filter include at least one of a number of reference frames in a set of reference frames, a filtering strength, and a decision of the temporal filter to allow / disallow a block including the first pixel. In some examples, the video content includes at least one of scene changes, a noise level of a frame, a signal-to-noise ratio of a block, and a pixel variance in the block.

[0025] In one example, the processing circuit determines a number of reference frames in a set of reference frames based on a noise level of the first frame.

[0026] In another example, the processing circuit determines a frame level filtering strength based on a noise level of the first frame.

[0027] In another example, the processing circuit determines at least one of a filtering strength and a quantization parameter for a block including the first pixel based on a signal-to-noise ratio of the block.

[0028] In another example, the processing circuit makes a decision to enable / disable application of the time domain filter to the block based on the complexity of the block in the first frame.

[0029] In some examples, the processing circuit determines a set of reference frames that are in the same scene as the first frame. Then, for a reference frame in the set of reference frames, the processing circuit derives a motion compensated reference frame based on a motion estimate between the reference frame and the first frame. The processing circuit may determine a filter value for the first pixel based at least in part on co-located pixels for the first pixel in the motion compensated reference frame. In some examples, the processing circuit determines the filter value for the first pixel based at least on non-co-located pixels for the first pixel in the motion compensated reference frame. In one example, the processing circuit determines the filter value based on a first number of non-co-located pixels in the first motion compensated reference frame and a second number of non-co-located pixels in the second motion compensated reference frame, the first motion compensated reference frame having a smaller temporal distance to the first frame than the second motion compensated reference frame, and the first number of non-co-located pixels is greater than the second number of non-co-located pixels.

[0030] Aspects of the present disclosure also provide a non-transitory computer-readable medium storing instructions, which, when executed by a computer for video processing, enables the computer to perform the video processing method. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Further features, properties and various advantages of the disclosed subject matter will become more apparent from the following detailed description and accompanying drawings, in which:

[0032] Figure 1A is a schematic diagram of an exemplary subset of intra prediction modes;

[0033] Figure 1B is a diagram of exemplary intra prediction directions;

[0034] Figure 2 is a schematic diagram of the current block and its surrounding spatial merge candidates in an example;

[0035] Figure 3 is a schematic diagram of a simplified block diagram of a communication system (300) according to one embodiment;

[0036] Figure 4 is a schematic diagram of a simplified block diagram of a communication system (400) according to one embodiment;

[0037] Figure 5 is a schematic diagram of a simplified block diagram of a decoder according to one embodiment;

[0038] Figure 6 is a schematic diagram of a simplified block diagram of an encoder according to one embodiment;

[0039] Figure 7shows a block diagram of an encoder according to another embodiment;

[0040] Figure 8 shows a block diagram of a decoder according to another embodiment;

[0041] Fig. 9 An encoding device according to some aspects of the present invention is shown;

[0042] Figures 10A-10B An example of a lookup table defining a reference filter strength is shown;

[0043] Fig.11 shows a process flow for noise estimation according to some examples;

[0044] Figures 12A-12B Some other examples of lookup tables defining reference filter strengths are shown;

[0045] Figures 13A-13B Some other examples of lookup tables defining reference filter strengths are shown;

[0046] Fig.14 An example of adjusting a reference range based on a scene cut according to some embodiments of the present disclosure is shown;

[0047] Fig.15 An example of a pattern of non-co-located pixels is shown;

[0048] Fig.16 An example of temporal filtering using non-co-located pixels according to some embodiments of the present disclosure is shown;

[0049] Fig.17 A flowchart showing an overview process according to an embodiment of the present disclosure is shown;

[0050] Fig.18 is a schematic diagram of a computer system according to one embodiment. DETAILED DESCRIPTION

[0051] Figure 3 A simplified block diagram of a communication system (300) according to an embodiment of the present disclosure is shown. The communication system (300) includes a plurality of terminal devices that can communicate with each other via, for example, a network (350). For example, the communication system (300) includes a first pair of terminal devices (310) and (320) interconnected via the network (350). Figure 3In the example of , a first pair of terminal devices (310) and (320) perform unidirectional transmission of data. For example, the terminal device (310) can encode video data (e.g., a video picture stream captured by the terminal device (310)) for transmission to another terminal device (320) via the network (350). The encoded video data can be transmitted in the form of one or more encoded video bitstreams. The terminal device (320) can receive the encoded video data from the network (350), decode the encoded video data to restore the video picture, and display the video picture based on the restored video data. Unidirectional data transmission is common in media service applications and the like.

[0052] In another example, the communication system (300) includes a second pair of terminal devices (330) and (340) that perform bidirectional transmission of encoded video data, such as may occur during a video conference. For bidirectional transmission of data, in one example, each of the terminal devices (330) and (340) can encode video data (e.g., a video picture stream captured by the terminal device) for transmission to the other of the terminal devices (330) and (340) via the network (350). Each of the terminal devices (330) and (340) can also receive encoded video data transmitted by the other of the terminal devices (330) and (340), and can decode the encoded video data to restore the video picture, and can display the video picture on an accessible display device based on the restored video data.

[0053] exist Figure 3 In the example of , terminal devices (310), (320), (330) and (340) can be shown as servers, personal computers and smart phones, but the principles of the present disclosure may not be limited to this. Embodiments of the present disclosure are applicable to laptop computers, tablet computers, media players and / or dedicated video conferencing equipment. Network (350) represents any number of networks that transmit encoded video data between terminal devices (310), (320), (330) and (340), including, for example, lines (wired) and / or wireless communication networks. Communication network (350) can exchange data in circuit switching and / or packet switching channels. Representative networks include telecommunication networks, local area networks, wide area networks and / or the Internet. For the purpose of the current discussion, the architecture and topology of network (350) may be unimportant to the operation of the present disclosure unless explained below.

[0054] As examples of applications of the disclosed subject matter, Figure 4The placement of a video encoder and a video decoder in a streaming environment is shown. The disclosed subject matter is equally applicable to other video-enabled applications including, for example, video conferencing, digital television, storing compressed video on digital media including CDs, DVDs, memory sticks, etc.

[0055] The streaming system may include: a capture subsystem (413), which may include a video source (401), such as a digital camera; creating, for example, an uncompressed video picture stream (402). In one example, the video picture stream (402) includes samples taken by the digital camera. The video picture stream (402) is depicted as thick lines to emphasize the high amount of data when compared to the encoded video data (404) (or encoded video bitstream), and can be processed by an electronic device (420) including a video encoder (403) coupled to the video source (401). The video encoder (403) may include hardware, software, or a combination thereof to implement or implement various aspects of the disclosed subject matter as described in more detail below. The encoded video data (404) (or encoded video bitstream (404)) is depicted as thin lines to emphasize the lower amount of data when compared to the video picture stream (402), and can be stored on a streaming server (405) for future use. One or more streaming client subsystems (e.g., Figure 4 The client subsystems (406) and (408) in the video server (405) can access the streaming server (405) to retrieve copies (407) and (409) of the encoded video data (404). The client subsystem (406) may include, for example, a video decoder (410) in an electronic device (430). The video decoder (410) decodes the input copy (407) of the encoded video data and creates an output video picture stream (411) that can be presented on a display (412) (e.g., a display screen) or other presentation device (not shown). In some streaming systems, the encoded video data (404), (407) and (409) (e.g., a video bitstream) can be encoded according to certain video encoding / compression standards. Examples of these standards include ITU-T Recommendation H.265. In one example, the video coding standard under development is informally referred to as Versatile Video Coding (VVC). The disclosed subject matter can be used in the context of VVC.

[0056] Note that the electronic devices (420) and (430) may include other components (not shown). For example, the electronic device (420) may include a video decoder (not shown), and the electronic device (430) may also include a video encoder (not shown).

[0057] Figure 5A block diagram of a video decoder (510) according to an embodiment of the present disclosure is shown. The video decoder (510) may be included in an electronic device (530). The electronic device (530) may include a receiver (531) (e.g., a receiving circuit). The video decoder (510) may be used to replace Figure 4 A video decoder (410) is shown in an example.

[0058] A receiver (531) may receive one or more encoded video sequences to be decoded by a video decoder (510); in the same or another embodiment, one at a time, wherein decoding of each encoded video sequence is independent of the other encoded video sequences. The encoded video sequences may be received from a channel (501), which may be a hardware / software link to a storage device storing the encoded video data. The receiver (531) may receive the encoded video data and other data, such as encoded audio data and / or auxiliary data streams, which may be forwarded to their respective consuming entities (not shown). The receiver (531) may separate the encoded video sequence from the other data. To combat network jitter, a buffer memory (515) may be coupled between the receiver (531) and an entropy decoder / parser (520) (hereinafter referred to as "parser (520)"). In some applications, the buffer memory (515) is part of the video decoder (510). In other cases, the buffer memory may be external to the video decoder (510) (not shown). In other cases, there may be a buffer memory (not shown) outside the video decoder (510), for example, to combat network jitter, and another buffer memory (515) inside the video decoder (510), for example, to handle playout timing. When the receiver (531) receives data from a store / forward device with sufficient bandwidth and controllability or from an isochronous network, the buffer memory (515) may not be needed, or may be small. For use over a best-effort packet network such as the Internet, a buffer memory (515) may be required, which may be relatively large and may advantageously have an adaptive size and may be implemented at least in part in an operating system or similar element (not shown) external to the video decoder (510).

[0059] The video decoder (510) may include a parser (520) to reconstruct symbols (521) from the encoded video sequence. The categories of these symbols include information for managing the operation of the video decoder (510) and potentially controlling a presentation device such as a presentation device (512) (e.g., a display screen) that is not part of the electronic device (530) but can be coupled to the electronic device (530), such as Figure 5As shown. The control information for the rendering device may be in the form of a supplemental enhancement information (SEI message) or a video usability information (VUI) parameter set fragment (not shown). The parser (520) may parse / entropy decode the received coded video sequence. The coding of the coded video sequence may be based on a video coding technique or standard and may follow various principles, including variable length coding, Huffman coding, arithmetic coding with or without context sensitivity, etc. The parser (520) may extract a set of subgroup parameters of at least one pixel subgroup 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), etc. The parser (520) may also extract information from the coded video sequence, such as transform coefficients, quantizer parameter values, motion vectors, etc.

[0060] The parser (520) may perform entropy decoding / parsing operations on the video sequence received from the buffer memory (515) to create symbols (521).

[0061] Depending on the type of coded video picture or part thereof (e.g., inter- and intra-pictures, inter- and intra-blocks) and other factors, the reconstruction of the symbol (521) may involve a number of different units. Which units are involved and how they are involved may be controlled by subgroup control information parsed from the coded video sequence by the parser (520). For clarity, such subgroup control information flow between the parser (520) and the following multiple units is not described.

[0062] In addition to the functional blocks already mentioned, the video decoder (510) can be conceptually subdivided into a number of functional units as described below. In a practical implementation operating under commercial constraints, many of these units interact closely with each other and may be at least partially integrated with each other. However, for the purpose of describing the disclosed subject matter, it is appropriate to conceptually subdivide into the following functional units.

[0063] The first unit is a scaler / inverse transform unit (551). The scaler / inverse transform unit (551) receives quantized transform coefficients and control information, including which transform to use, block size, quantization factor, quantization scaling matrix, etc., as symbols (521) from the parser (520). The scaler / inverse transform unit (551) can output blocks including sample values, which can be input into an aggregator (555).

[0064] In some cases, the output samples of the scalar / inverse transform unit (551) may belong to an intra-coded block; that is, a block that does not use prediction information from a previously reconstructed image, but may use prediction information from a previously reconstructed portion of the current picture. Such prediction information may be provided by an intra-picture prediction unit (552). In some cases, the intra-picture prediction unit (552) generates a block of the same size and shape as the block being reconstructed using surrounding already reconstructed information obtained from the current picture buffer (558). The current picture buffer (558) buffers, for example, a partially reconstructed current picture and / or a fully reconstructed current picture. In some cases, the aggregator (555) adds the prediction information already generated by the intra-picture prediction unit (552) to the output sample information provided by the scalar / inverse transform unit (551) on a per-sample basis.

[0065] In other cases, the output samples of the scalar / inverse transform unit (551) may belong to an inter-frame coded and possibly motion compensated block. In this case, the motion compensated prediction unit (553) may access the reference picture memory (557) to obtain samples for prediction. After the extracted samples are motion compensated according to the symbols (521) associated with the block, these samples may be added by the aggregator (555) to the output of the scalar / inverse transform unit (551) (in this case referred to as residual samples or residual signal) to generate output sample information. The addresses within the reference picture memory (557) from which the motion compensated prediction unit (553) obtains the predicted samples may be controlled by motion vectors, and the motion compensated prediction unit (553) may obtain these addresses in the form of symbols (521), which may have, for example, X, Y and reference picture components. Motion compensation may also include: interpolation of sample values ​​obtained from the reference picture memory (557) when sub-sample exact motion vectors are used, motion vector prediction mechanisms, etc.

[0066] The output samples of the aggregator (555) may be subjected to various loop filtering techniques in a loop filter unit (loop filter unit) (556). The video compression techniques may include loop filtering techniques which are controlled by parameters contained in the coded video sequence (also referred to as the coded video bitstream) and made available to the loop filter unit (556) as symbols (521) from the parser (520), but may also be responsive to meta-information obtained during decoding of a previous (in decoding order) portion of the coded picture or coded video sequence and to previously reconstructed and loop filtered sample values.

[0067] The output of the loop filter unit (556) may be a sample stream that may be output to a rendering device (512) and stored in a reference picture memory (557) for future inter-picture prediction.

[0068] Once fully reconstructed, certain coded pictures can be used as reference pictures for future predictions. For example, once a coded picture corresponding to a current picture is fully reconstructed, and the coded picture has been identified as a reference picture (e.g., by a parser (520)), the current picture buffer (558) can become part of the reference picture memory (557), and a new current picture buffer can be reallocated before starting reconstruction of the next coded picture.

[0069] The video decoder (510) may perform decoding operations according to a predetermined video compression technique in a standard such as ITU-T Rec. H.265. The encoded video sequence may conform to the syntax specified by the video compression technology or standard used in the sense that the encoded video sequence conforms to the syntax of the video compression technology or standard and the profile recorded in the video compression technology or standard. Specifically, the profile may select certain tools from all the tools available in the video compression technology or standard as the only tools available under the profile. Conformance to the standard also requires that the complexity of the encoded video sequence is within the range defined by the level of the video compression technology or standard. In some cases, the level limits the maximum image size, maximum frame rate, maximum reconstruction sampling rate (e.g., measured in megasamples per second), maximum reference picture size, etc. In some cases, the limits set by the level may be further limited by the metadata of the hypothetical reference decoder (HRD) specification and HRD buffer management signaled in the encoded video sequence.

[0070] In one embodiment, the receiver (531) can receive additional (redundant) data with the encoded video. The additional data can be included as part of the encoded video sequence. The video decoder (510) can use the additional data to correctly decode the data and / or more accurately reconstruct the original video data. The additional data can be in the form of, for example, time domain, spatial or signal-to-noise ratio (SNR) enhancement layers, redundant slices, redundant pictures, forward error correction codes, etc.

[0071] Figure 6 A block diagram of a video encoder (603) according to an embodiment of the present disclosure is shown. The video encoder (603) is included in an electronic device (620). The electronic device (620) includes a transmitter (640) (e.g., a transmitting circuit). The video encoder (603) can be used to replace Figure 4 The video encoder (403) in the example.

[0072] The video encoder (603) can be used to obtain the video source (601) (which is not Figure 6 In another example, the video source (601) is a part of the electronic device (620) to receive the video samples, and the video source can capture the video pictures to be encoded by the video encoder (603). In another example, the video source (601) is a part of the electronic device (620).

[0073] The video source (601) may provide a source video sequence to be encoded by the video encoder (603) in the form of a digital video sample stream, which 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 (601) may be a storage device storing previously prepared videos. In a video conferencing system, the video source (601) may be a camera that captures local image information as a video sequence. Video data may be provided as multiple individual pictures that impart motion when viewed sequentially. The pictures themselves may be organized as a spatial array of pixels, where each pixel may include one or more samples, depending on the sampling structure, color space, etc. in use. The relationship between pixels and samples may be readily understood by those skilled in the art. The following description focuses on samples.

[0074] According to one embodiment, the video encoder (603) can encode and compress the pictures of the source video sequence into an encoded video sequence (643) in real time or under any other time constraints required by the application. Implementing the appropriate encoding speed is a function of the controller (650). In some embodiments, the controller (650) controls other functional units as described below and is functionally coupled to the other functional units. For clarity, the coupling is not described. The parameters set by the controller (650) may include rate control related parameters (picture skipping, quantizer, lambda value of rate distortion optimization technology, ...), picture size, picture group (GOP) layout, maximum motion vector search range, etc. The controller (650) can be configured to have other suitable functions related to the video encoder (603) optimized for a specific system design.

[0075] In some embodiments, the video encoder (603) is configured to operate in an encoding loop. As an oversimplified description, in one example, the encoding loop may include a source encoder (630) (e.g., responsible for creating symbols, e.g., a symbol stream, based on an input picture to be encoded and a reference picture) and a (local) decoder (633) embedded in the video encoder (603). The decoder (633) reconstructs the symbols in a manner similar to what the (remote) decoder will also create to create sample data (because in the video compression techniques considered in the disclosed subject matter, any compression between the symbols and the encoded video bitstream is lossless). The reconstructed sample stream (sample data) is input to a reference picture memory (634). Since the decoding of the symbol stream results in a bit-exact result independent of the decoder location (local or remote), the contents in the reference picture memory (634) are also bit-exact between the local encoder and the remote encoder. In other words, when prediction is used during decoding, the predicted part of the encoder "sees" the same sample values ​​as the sample values ​​"seen" by the decoder as reference picture samples. This basic principle of reference picture synchronization (and the resulting drift if the synchronization cannot be maintained, eg due to channel errors) is also used in some related techniques.

[0076] The operation of the "local" decoder (633) may be identical to the operation of a "remote" decoder such as the video decoder (510), described above in conjunction with Figure 5 However, a brief reference to Figure 5 , since symbols are available and the symbol encoding / decoding of the encoded video sequence by the entropy encoder (645) and the parser (520) can be lossless, the entropy decoding portion of the video decoder (510), including the buffer memory (515) and the parser (520), may not be fully implemented in the local decoder (633).

[0077] It can be observed at this point that, in addition to the parsing / entropy decoding present in the decoder, any decoder technology must also be present in the corresponding encoder in substantially the same functional form. For this reason, the disclosed subject matter focuses on the decoder operation. The description of the encoder technology can be simplified because these technologies are the inverse of the fully described decoder technology. Only in certain areas is a more detailed description required and provided below.

[0078] During operation, in some examples, the source encoder (630) may perform motion compensated predictive coding, which predictively encodes an input picture with reference to one or more previously encoded pictures from a video sequence that are designated as “reference pictures.” In this manner, the encoding engine (632) 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.

[0079] The local video decoder (633) can decode the encoded video data of the picture that can be designated as the reference picture based on the symbols created by the source encoder (630). The operation of the encoding engine (632) can advantageously be a lossy process. When the encoded video data can be decoded at the video decoder ( Figure 6 When decoded at a remote video decoder (not shown), the reconstructed video sequence may typically be a copy of the source video sequence with some errors. The local video decoder (633) 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 (634). In this way, the video encoder (603) may locally store copies of the reconstructed reference pictures that have the same content (absent transmission errors) as the reconstructed reference pictures that will be obtained by the remote video decoder.

[0080] The predictor (635) may perform a prediction search on the encoding engine (632). That is, for a new picture to be encoded, the predictor (635) may search the reference picture memory (634) for sample data (as candidate reference pixel blocks) or certain metadata, such as reference picture motion vectors, block shapes, etc., that may be used as appropriate prediction references for the new picture. The predictor (635) may operate on a sample block-pixel block basis to find an appropriate prediction reference. In some cases, as determined by the search results obtained by the predictor (635), the input picture may have prediction references extracted from multiple reference pictures stored in the reference picture memory (634).

[0081] The controller (650) may manage encoding operations of the source encoder (630), including, for example, the setting of parameters and sub-group parameters for encoding video data.

[0082] The outputs of all the aforementioned functional units may undergo entropy coding in an entropy encoder (645). The entropy encoder (645) converts the symbols generated by the various functional units into a coded video sequence by losslessly compressing the symbols according to techniques such as Huffman coding, variable length coding, arithmetic coding, etc.

[0083] The transmitter (640) can buffer the encoded video sequence created by the entropy encoder (645) in preparation for transmission via a communication channel (660), which can be a hardware / software link to a storage device where the encoded video data will be stored. The transmitter (640) can combine the encoded video data from the video encoder (603) with other data to be transmitted, such as encoded audio data and / or auxiliary data streams (source not shown).

[0084] The controller (650) can manage the operation of the video encoder (603). During encoding, the controller (650) can assign a specific coded picture type to each coded picture, which can affect the coding techniques that can be applied to the corresponding picture. For example, a picture can generally be assigned one of the following picture types:

[0085] An intra picture (I picture) may be a picture that is 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 those variants of I pictures and their corresponding applications and features.

[0086] A prediction picture (P picture) may be a picture that is encoded and decoded using intra prediction or inter prediction by predicting sample values ​​of each block using at most one motion vector and a reference index.

[0087] Bidirectional prediction pictures (B pictures) can be pictures that use up to two motion vectors and reference indices to predict the sample values ​​of each block, and are encoded and decoded using intra-frame prediction or inter-frame prediction. Similarly, multi-prediction pictures can use more than two reference pictures and related metadata to reconstruct a single block.

[0088] A source picture may typically be spatially subdivided into a number of blocks of samples (e.g., 4×4, 8×8, 4×8, or 16×16 blocks of samples each), and encoded on a block-by-block basis. Blocks may be predictively encoded with reference to other (already encoded) blocks determined by the coding allocation applied to the block's corresponding picture. For example, blocks of an I picture may be non-predictively encoded, or may be predictively encoded (spatial prediction or intra prediction) with reference to already encoded blocks of the same picture. Blocks of pixels of a P picture may be predictively encoded with reference to one previously encoded reference picture, either via spatial prediction or via temporal prediction. Blocks of a B picture may be predictively encoded with reference to one or two previously encoded reference pictures, either via spatial prediction or via temporal prediction.

[0089] The video encoder (603) may perform encoding operations according to a predetermined video encoding technique or standard (e.g., ITU-T Rec. H.265). In its operation, the video encoder (603) may perform various compression operations, including predictive encoding operations that exploit temporal and spatial redundancy in the input video sequence. Thus, the encoded video data may conform to the syntax specified by the video encoding technique or standard being used.

[0090] In one embodiment, the transmitter (640) may transmit additional data along with the encoded video. The source encoder (630) may include such data as part of the encoded video sequence. The additional data may include temporal / spatial / SNR enhancement layers, other forms of redundant data (e.g., redundant pictures and slices), SEI messages, VUI parameter set fragments, etc.

[0091] Video can be captured as multiple source pictures (video pictures) in a temporal sequence. Intra-picture prediction (often abbreviated as intra-prediction) exploits spatial correlations in a given picture, while inter-picture prediction exploits (temporal or other) correlations between pictures. In one example, a particular picture in encoding / decoding, referred to as the current picture, is divided into blocks. 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 can be encoded by a vector called a motion vector. In the case of using multiple reference pictures, the motion vector points to a reference block in a reference picture and can have a third dimension that identifies the reference picture.

[0092] 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, both of which are before the current picture in the video in decoding order (but may be in the past and future, respectively, in display order). 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. The block may be predicted by a combination of the first reference block and the second reference block.

[0093] In addition, merge mode techniques can be used in inter-picture prediction to improve coding efficiency.

[0094] According to some embodiments of the present disclosure, prediction is performed in units of blocks, for example, inter-picture prediction and intra-picture prediction. For example, according to the HEVC standard, a picture in a video picture sequence is divided into coding tree units (CTUs) for compression, and the CTUs in the picture have the same size, for example, 64×64 pixels, 32×32 pixels, or 16×16 pixels. Typically, a CTU includes three coding tree blocks (CTBs), namely a luminance CTB and two chrominance CTBs. Each CTU can be recursively quadtree-divided into one or more coding units (CUs). For example, a 64×64 pixel CTU can be divided into a 64×64 pixel CU, or 4 32×32 pixel CUs, or 16 16×16 pixel CUs. In one example, each CU is analyzed to determine the prediction type of the CU, for example, an inter-prediction type or an intra-prediction type. According to temporal and / or spatial predictability, the CU is divided 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. Using a luma prediction block as an example of a prediction block, the prediction block contains a matrix of pixel values ​​(e.g., luma values), such as 8×8 pixels, 16×16 pixels, 8×16 pixels, 16×8 pixels, etc.

[0095] Figure 7 A diagram of a video encoder (703) according to another embodiment of the present disclosure is shown. The video encoder (703) is configured to receive a processed block (e.g., a prediction block) of sample values ​​within a current video picture in a sequence of video pictures and encode the processed block into an encoded image as part of an encoded video sequence. In one example, the video encoder (703) is used instead of Figure 4 The video encoder (403) in the example.

[0096] In the HEVC example, the video encoder (703) receives a matrix of sample values ​​for a processing block, such as a prediction block of 8×8 samples, etc. The video encoder (703) determines whether to best encode the processing block using intra mode, inter mode, or a bidirectional prediction mode such as rate-distortion optimization. When the processing block is to be encoded in intra mode, the video encoder (703) may encode the processing block into a coded picture using intra prediction techniques; and when the processing block is to be encoded in inter mode or bidirectional prediction mode, the video encoder (703) may encode the processing block into a coded picture using inter prediction or bidirectional prediction techniques, respectively. In some video coding techniques, the merge mode may be an inter picture prediction submode, in which motion vectors are derived from one or more motion vector predictors without benefiting from a coded motion vector component outside the predictor. In some other video coding techniques, there may be a motion vector component applicable to the object block. In one example, the video encoder (703) includes other components, such as a mode decision module (not shown) for determining the mode of the processing block.

[0097] exist Figure 7 In the example of FIG. 7 , the video encoder ( 703 ) includes Figure 7 An inter-frame encoder (730), an intra-frame encoder (722), a residual calculator (723), a switch (726), a residual encoder (724), a general controller (721), and an entropy encoder (725) are shown coupled together.

[0098] The inter-frame encoder (730) is configured 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., description of redundant information according to an inter-frame coding technique, motion vectors, merge mode information), and calculate an inter-frame prediction result (e.g., a prediction block) based on the inter-frame prediction information using any suitable technique. In some examples, the reference picture is a decoded reference picture decoded based on the encoded video information.

[0099] The intra encoder (722) is configured to receive samples of a current block (e.g., a processing block), compare the block with blocks already encoded in the same picture, generate quantization coefficients after transformation, and in some cases, generate intra prediction information (e.g., intra prediction direction information according to one or more intra coding techniques). In one example, the intra encoder (722) also calculates an intra prediction result (e.g., a prediction block) based on the intra prediction information and a reference block in the same picture.

[0100] The general controller (721) is configured to determine general control data and control other components of the video encoder (703) based on the general control data. In one example, the general controller (721) determines the mode of the block and provides a control signal to the switch (726) based on the mode. For example, when the mode is intra-frame mode, the general controller (721) controls the switch (726) to select the intra-frame mode result for use by the residual calculator (723), and controls the entropy encoder (725) to select the intra-frame prediction information and include the intra-frame prediction information in the bitstream; when the mode is inter-frame mode, the general controller (721) controls the switch (726) to select the inter-frame prediction result for use by the residual calculator (723), and controls the entropy encoder (725) to select the inter-frame prediction information and include the inter-frame prediction information in the bitstream.

[0101] The residual calculator (723) is configured to calculate the difference (residual data) between the received block and the prediction result selected from the intra encoder (722) or the inter encoder (730). The residual encoder (724) is configured to operate based on the residual data to encode the residual data to generate a transform coefficient. In one example, the residual encoder (724) is configured to convert the residual data from the spatial domain to the frequency domain and generate a transform coefficient. The transform coefficient is then quantized to obtain a quantized transform coefficient. In various embodiments, the video encoder (703) further includes a residual decoder (728). The residual decoder (728) is configured to perform an inverse transform and generate decoded residual data. The decoded residual data can be appropriately used by the intra encoder (722) and the inter encoder (730). For example, the inter encoder (730) can generate a decoded block based on the decoded residual data and the inter prediction information, and the intra encoder (722) can generate a decoded block based on the decoded residual data and the intra prediction information. The decoded blocks are processed appropriately to generate a decoded picture, and the decoded picture may be cached in memory circuitry (not shown) and used as a reference picture in some examples.

[0102] The entropy encoder (725) is configured to format the bitstream to include the coded blocks. The entropy encoder (725) is configured to include various information according to a suitable standard, such as the HEVC standard. In one example, the entropy encoder (725) is configured to include general control data, selected prediction information (e.g., intra-frame prediction information or inter-frame prediction information), residual information, and other suitable information in the bitstream. Note that according to the disclosed subject matter, when the block is encoded in inter-frame mode or the merge sub-mode of the bidirectional prediction mode, there is no residual information.

[0103] Figure 8A diagram of a video decoder (810) according to another embodiment of the present disclosure is shown. The video decoder (810) is configured to receive an encoded picture as part of an encoded video sequence and decode the encoded picture to generate a reconstructed picture. In one example, the video decoder (810) is used to replace Figure 4 A video decoder (410) is shown in an example.

[0104] exist Figure 8 In the example of FIG. 8 , the video decoder ( 810 ) includes Figure 8 An entropy decoder (871), an inter-frame decoder (880), a residual decoder (873), a reconstruction module (874) and an intra-frame decoder (872) are shown coupled together.

[0105] The entropy decoder (871) can be configured to reconstruct certain symbols representing syntax elements constituting the coded image from the coded image. Such symbols may include, for example, a mode for encoding a block (e.g., intra mode, inter mode, bidirectional prediction mode, merge submode, or the latter two modes in another submode), prediction information (e.g., intra prediction information or inter prediction information) that can identify a specific sample or metadata used for prediction by an intra decoder (872) or an inter decoder (880), respectively, residual information such as quantized transform coefficients, etc. In one example, when the prediction mode is an inter or bidirectional prediction mode, the inter prediction information is provided to the inter decoder (880); and when the prediction type is an intra prediction type, the intra prediction information is provided to the intra decoder (872). The residual information may be subjected to inverse quantization and provided to the residual decoder (873).

[0106] The inter-frame decoder (880) is configured to receive the inter-frame prediction information and generate an inter-frame prediction result based on the inter-frame prediction information.

[0107] The intra decoder (872) is configured to receive intra prediction information and generate a prediction result based on the intra prediction information.

[0108] The residual decoder (873) is configured 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 (873) may also require certain control information (to include quantizer parameters (QP)), and this information may be provided by the entropy decoder (871) (the data path is not shown because this may only be a small amount of control information).

[0109] The reconstruction module (874) is configured to combine the residual output by the residual decoder (873) and the prediction result (output by the inter-frame or intra-frame prediction module, as appropriate) 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. Note that other suitable operations such as deblocking operations can be performed to improve visual quality.

[0110] Note that the video encoders (403), (603) and (703) and the video decoders (410), (510) and (810) can be implemented using any suitable technology. In one embodiment, the video encoders (403), (603) and (703) and the video decoders (410), (510) and (810) can be implemented using one or more integrated circuits. In another embodiment, the video encoders (403), (603) and (603) and the video decoders (410), (510) and (810) can be implemented using one or more processors that execute software instructions.

[0111] Describe the application.

[0112] Aspects of the present disclosure provide techniques for time domain filtering. Time domain filtering is used as a pre-processing step at the encoder side.

[0113] Fig. 9 An encoding device (901) according to some aspects of the present disclosure is shown. The encoding device (901) can be any suitable device, such as a desktop computer, a server computer, a laptop computer, a tablet computer, a sensor device, a video capture device, a camera, an embedded computing device, etc. The encoding device (901) can generate an encoded video bitstream carrying a video. In an example, the encoding device (901) is implemented in an electronic device, such as the electronic device (420), the electronic device (620), etc.

[0114] exist Fig. 9 In an example, the encoding device (901) includes a temporal filter (910) and a video encoder (920). The temporal filter (910) can operate on an uncompressed video and generate a filtered video. The video encoder (920) can encode the filtered video and output an encoded video bitstream carrying the filtered video. In some examples, the temporal filter (910) and the video encoder (920) are respectively implemented by circuits. In some examples, the temporal filter (910) and the video encoder (920) are respectively implemented by processors that execute software instructions. The temporal filter (910) can be configured according to the following description.

[0115] According to some aspects of the present disclosure, a temporal filter (910) may operate on a current picture frame (also referred to as a temporal filter frame or TF frame) in a video based on other frames in the video, for example, adjacent frames before the TF frame in the video, adjacent frames after the TF frame in the video. The temporal filter (TF) (910) may increase the similarity between the current TF frame and adjacent frames in the filtered video. In some examples, when encoding the filtered video, the similarity between the current TF frame and adjacent frames may reduce residual information and improve coding efficiency.

[0116] In some examples (e.g., the VVC Test Model (VTM)), temporal filtering is applied to each picture with an interval picture order count (POC) of 16 or 8. For example, up to 4 reference frames in the forward direction and / or up to 4 reference frames in the backward direction are used to derive weights for bilateral filtering. In some examples, the number of available reference frames is represented by a. In one example, when a reference frame is available on one side of the TF frame, a can have a value of 4; and when a reference frame is available on both sides of the TF frame, a can have a value of 8. The sample in the TF frame at the kth spatial position in the TF frame can be filtered according to equation (1):

[0117]

[0118] Among them, I o (k) represents the original pixel (sample) at the spatial position k in the TF frame, I n (k) represents the filtered pixel (sample), I r (i, k) represents the co-located pixel at the i-th motion compensated reference frame (also at the k-th spatial position or having the same coordinates after motion compensation) (i represents the index of the reference frame or the index of the motion compensated reference frame). r represents the motion compensated reference frame derived by performing motion estimation between the TF frame and the original reference frame and then performing motion compensation from the original reference frame. r (i, a, k) represents the weight of the i-th motion compensation reference frame (with a plurality of available reference frames) at the spatial position k in the TF frame. In one example, the weight can be derived according to equation (2):

[0119]

[0120] Wherein, parameter bw represents the base weight and has a value of 0.4 in one example. Parameter s0 represents the basic filtering strength and can be determined based on the interval POC. In one example, if the interval POC is divisible by 16, the value of s0 is 1.5; otherwise, if the interval POC is divisible by 8, the value of s0 is 0.95. Parameter s r (i, a) represents the reference filtering strength and can be defined by a lookup table, and the reference Figures 10A-10B Parameter ΔI(i, k) represents the pixel value difference between the original pixel at spatial position k and its co-located pixel in the i-th motion compensated reference frame. Parameter sw represents the σ-based weight 2, for example, having a constant value of 2. Parameter σ i (QP) can be determined by equation (3):

[0121] σ i (QP) = 3 × (QP - 10) Equation (3)

[0122] Wherein, QP represents a slice quantization parameter. In some examples, the base weight bw and the σ weight sw may be variables and may be adaptively adjusted for each block (eg, 8×8 (sample) block) based on the block error and the block frequency weight.

[0123] Figures 10A-10B shows the definition of the reference filter strength s r An example of a lookup table for (i, a). In one example, Fig. 10A A lookup table (1010) is shown which can be used to determine the reference filter strength s when the number of available reference frames a has a value of 4. r For example, the reference frame is available on one side of the TF frame, for example, before the TF frame or after the TF frame.

[0124] In another example, Fig. 10B A lookup table (1020) is shown which can be used to determine the reference filter strength s when the number of available reference frames a has a value of 8. r For example, there are 4 reference frames available before the TF frame and 4 reference frames available after the TF frame.

[0125] In some examples (e.g., AOMedia Video (AV1), Scalable Video Technology for AV1 (SVT-AV1)), a temporal filter may be used to filter key frames and may be used to generate alternative reference frames (denoted by ALTREF). ALTREF is a non-displayable picture frame that is used as a reference for other picture frames. Pixel weights may be calculated differently compared to temporal filtering in VTM. In one example, the temporal filter in SVT-AV1 adaptively selects the filter strength based on noise information (e.g., based on equation (4)).

[0126]

[0127] Among them, altref_strength represents the filter strength, σ n Indicates the noise level of the current TF frame.

[0128] In some examples, the parameter altref_nframes represents the number of alternative reference frames and can be adjusted by removing references with significant illumination changes. In one example, if the difference in the cumulative brightness histogram is significantly different from a given threshold represented by ahd, the reference picture will be removed. In one example, the threshold is calculated according to equation (5):

[0129] ahd=0.5×W×H Equation (5)

[0130] Wherein, W represents the width of the current frame, and H represents the height of the current frame.

[0131] According to some aspects of the present disclosure, certain techniques may be used in the temporal filter (910), such as scene cut detection, noise estimation, simple scene (content) detection, etc. Scene cut detection is a technique for detecting whether a scene has changed. A scene change occurs in a video when the content changes from one scene to another. Scene changes can result in significant changes in content and can be detected by evaluating the differences between adjacent pictures.

[0132] In some examples, noise estimation is a technique that estimates the noise level by evaluating the gradient energy of the image. In addition, local content such as edges, smooth areas, or textures can be further exploited to derive the noise level with higher accuracy.

[0133] Fig.11 A process flow (1100) for noise estimation according to some examples is shown. The process flow (1100) includes an edge detection step (1110), a Laplacian convolution step (1120), and an averaging step (1130).

[0134] During the edge detection step (1110), in one example, a Sobel operation is used for edge detection in order to exclude edges from noise detection. In one example, the current picture is represented as I, and (x, y) represents the coordinates of the pixel. The output of the Sobel operation can be described according to equation (6):

[0135]

[0136] Here, |·| represents an absolute operator. In one example, a threshold value G of G is used. th To determine the edge map. For example, in the Laplacian convolution step (1120), the noise detection G<G th The pixels of are used with the Laplacian operator. The noise level calculation by the Laplacian convolution step (1120) and the averaging step (1130) can be performed according to equation (7):

[0137]

[0138] Where N is the Laplacian operator and is defined in one example according to equation (8):

[0139]

[0140] Simple local scene (also called local content) detection is a technique for detecting a specific scene (e.g., a blank scene, etc.) of certain attributes in a local area (e.g., a block). In one example, a blank local scene can be detected for a block with B×B pixels based on, for example, pixel variance, pixel value range (e.g., the difference between the maximum pixel value and the minimum pixel value in the block, max_pixel_val min_pixel_val), etc.

[0141] Various aspects of the present disclosure provide techniques for adjusting temporal filtering based on video content attributes. In some examples, temporal filtering can be adjusted based on scene changes. In some examples, temporal filtering can be adjusted based on noise levels and local content of the current TF frame. For example, the local content can be a dark area, a simple area, or a blank area. In some examples, temporal filtering can be adjusted to include non-co-located pixels, for example, neighboring pixels of co-located pixels in a motion compensated reference frame.

[0142] According to one aspect of the present disclosure, a temporal filter can be defined with various filtering parameters, and the filtering parameters of the temporal filter can be adaptively adjusted based on the source video content attributes. The filtering parameters that can be adaptively adjusted include, but are not limited to, the number of reference frames, the filtering strength, and the decision to apply or not apply the temporal filter to a block (referred to as an enable / disable decision). Video content attributes include, but are not limited to, scene changes, noise levels, local signal-to-noise ratios, and whether local scenes have small pixel changes or are simple (e.g., simple local scenes).

[0143] In one embodiment, the number of reference frames is adaptively determined according to the noise level of the TF frame. The available number of reference frames a on one side is called a reference range ar. In some examples, the reference range ar is increased to greater than 4, and a larger reference range can increase the dependency among the TF frames of a group of pictures (GOP).

[0144] In one example, the reference range ar is 6. When there is a reference frame on one side of the TF frame, 6 reference frames are available; when there are reference frames on both sides of the TF frame, 12 reference frames are available. r (f, a) can be defined by a lookup table.

[0145] Fig. 12A A lookup table (1210) for determining a reference filtering strength when the reference range ar is 6 and the reference frame is on one side of the TF frame is shown. Fig. 12B A lookup table (1220) for determining the reference filtering strength when the reference range ar is 6 and the reference frames are on both sides of the TF frame is shown.

[0146] In one example, the reference range ar is 8. When there is a reference frame on one side of the TF frame, 8 reference frames are available; when there are reference frames on both sides of the TF frame, 16 reference frames are available. r (f, a) can be defined by a lookup table.

[0147] Fig.13A A lookup table (1310) for determining a reference filtering strength when the reference range ar is 8 and the reference frame is on one side of the TF frame is shown. Fig. 13B A lookup table (1320) for determining the reference filtering strength when the reference range ar is 8 and the reference frames are on both sides of the TF frame is shown.

[0148] In some examples, based on the noise value, for example, by σ nThe frame level noise value represented by , adaptively adjusts the reference range ar. In one example, the frame level noise value is calculated according to the processing flow (1100) and equations 6 to 8. Then, according to equation (9), based on σ n The frame-level noise value is expressed to determine the reference range ar:

[0149]

[0150] Where TH1 and TH2 represent thresholds. Specifically, if the frame-level noise value σ n is equal to or lower than TH1, then the reference range ar can be 4. If the frame level noise value σ n If the frame level noise value σ is higher than TH1 but equal to or lower than TH2, the reference range ar can be adjusted to 6; n When TH1 is higher than TH2, the reference range ar may be adjusted to 8. In one example, TH1 is equal to 1, and TH2 is equal to 2.

[0151] In another embodiment, the frame-level or block-level filtering strength is adaptively determined based on the noise level. In some examples, the filter strength (frame level or block level) is related to the noise level denoted as α. n The value of (referred to as the adjusted noise factor) is adjusted symmetrically. Specifically, in one example, by using the modified weight s n (For example, s0×s n ) adaptively adjusts the basic filtering strength s0 to filter the noisier frames more strongly, and the modified weight s can be determined according to equation (10) n :

[0152]

[0153] Where TH3 and TH4 represent thresholds. Specifically, if the frame-level noise value σ n is equal to or lower than TH3, then the modified weight s n Can be 1-α n If the frame-level noise value σ n Higher than TH3, but equal to or lower than TH4, the modified weight s n It can be 1; when the frame level noise value σ n When it is higher than TH4, the modified weight s n Can 1+α nIn one example, TH3 is equal to 1 and TH4 is equal to 2. n ∈(0, 1.0) represents the adjusted noise factor. n is a predetermined value. In one example, α n The value of is 0.6.

[0154] In another embodiment, the filter strength and QP are further adjusted at the block level of size B×B in pixels. For each non-overlapping B×B block, for example, the signal-to-noise ratio of the bth block is calculated according to equation (11):

[0155]

[0156] in, Indicates that it belongs to the original picture I o The kth pixel of the bth B×B block of . The filtering strength is further adjusted according to equation (12):

[0157]

[0158] Wherein, TH5 and TH6 represent thresholds. In one example, TH5 is equal to 25, TH6 is equal to 50; snr ∈(0,1) is the SNR adjustment factor. In one example, α snr = 0.2 gives a good result.

[0159] Based on SNR b value, adjust QP according to equation (13):

[0160]

[0161] Wherein, TH7 and TH8 represent thresholds. In one example, TH7 is equal to 25, and TH8 is equal to 50; (e.g., a positive integer) is an adjusted QP factor based on snr. In one example, α QP =1.

[0162] In another embodiment, whether to filter a block is adaptively determined based on the complexity of the block. In some examples, the picture is divided into B×B (B is a positive integer) non-overlapping blocks, for example, 8×8 (sample) blocks, 16×16 (sample) blocks, etc. The characteristics of the B×B blocks are used to adaptively control the TF filtering.

[0163] In some examples, a blank block has the same value for all pixels in the blank block. In the case of a blank block, temporal filtering may not improve encoding performance. Therefore, in one example, temporal filtering may be skipped for pixels in a blank block.

[0164] In another example, some blocks (e.g., smaller blocks) may have small variances in pixel values. For pixels in small blocks with very small variances, strong temporal filtering may result in significant distortion of the original pixels in the small blocks. In one example, a weight referred to as a low contrast (LC) weight may be applied. In one example, the low contrast weight may be determined according to equation (14):

[0165]

[0166] Wherein, TH9 represents a threshold value, and max_pix_b and min_pix_b represent the maximum and minimum pixel values ​​in the b-th non-overlapping B×B block. In one example, TH9 is equal to 5.

[0167] According to an embodiment of the present disclosure, when considering the weight s n , When , the bilateral weight is set to equation (15):

[0168]

[0169] In another embodiment, the number of reference frames is adaptively determined based on whether the reference frames belong to the same scene.

[0170] Temporal filtering is effective in processing various video contents with slow and fast motion. However, because image frames from different scenes are likely to be different, temporal filtering may not be effective in filtering TF frames using images from different scenes. Therefore, in some embodiments, temporal filtering is not used in scene switching. The reference range can be adjusted according to scene switching.

[0171] Fig.14 An example of adjusting the reference range based on scene switching according to some embodiments of the present disclosure is shown. Fig.14 In the example of , the original reference range includes 4 frames before the TF frame and 4 frames after the TF frame. For example, when the picture order count (POC) of the TF frame is C, the 4 frames before the TF frame have POCs from C-1 to C-4, and the 4 frames after the TF frame have POCs from C+1 to C+4.

[0172] In some examples, scene cut detection is performed in forward and backward directions starting from the TF frame according to the picture sequence count. Then, the frame in the same scene as the TF frame is determined as the reference frame of the TF frame. Fig.14In the example, three scenes (scene 0, scene 1, and scene 2) are detected. The first scene scene0 includes C-4 frames, the second scene scene1 includes C-3 to C+1 frames, and the third scene scene2 includes C+2 to C+4 frames. Frames C-3, C-2, C-1, and C+1 are in the same scene as the TF frame and can be used as reference frames for the TF frame, so the adjusted reference range is from C-3 frame to C+1 frame, excluding the TF frame itself. Frames from other scenes (for example, C-4 frame in the first scene scene0 and C+2 to C+4 frames in the third scene scene2) can be marked as unavailable during the temporal filtering process.

[0173] According to another aspect of the present disclosure, non co-located pixels can be used for temporal filtering. In some examples, in addition to the co-located pixels in the motion compensated reference frame, the temporal filtering can use additional non co-located pixels in the motion compensated reference frame to determine the average, for example, adding the non co-located pixels in equation (1).

[0174] In some examples, additional points from the motion compensated reference frame are used for temporal filtering. In one example, the co-located pixel in the rth motion compensated reference frame is at position (x, y) (also referred to as spatial position k), and the additional non-co-located pixel in the rth motion compensated reference frame may have position (x±Δx, y±Δy) (also referred to as spatial position) k r In one example, Δx, Δy are set to 1.

[0175] In some examples, a pattern of non-co-located pixels is defined.

[0176] Fig.15 Examples of patterns of non-co-located pixels are shown. Fig.15 In the example, the mode (1510) includes Fig.15 The eight points of the co-located pixels shown are adjacent to each other; the pattern (1520) includes the following: Fig.15 The pattern (1530) includes the following: Fig.15 The pattern (1540) includes the following: Fig.15 The two points shown in the vertical direction are co-located pixels adjacent to each other; the pattern (1550) includes the following Fig.15 The co-located pixels are adjacent to each other in the horizontal direction as shown; the pattern (1560) includes the following: Fig.15 The two points shown in FIG. 1 are adjacent to the co-located pixels in the diagonal direction; the pattern (1570) includes the following: Fig.15 Two points are shown as being adjacent to the co-located pixels in another diagonal direction.

[0177] Fig.16 An example of temporal filtering using non-co-located pixels according to some embodiments of the present disclosure is shown. Fig.16 In the example of , motion compensation reference frames R1-R16 are derived for TF frames. For a pixel (1601) in the TF frame, the temporal filter can use the co-located pixels in the motion compensation reference frames R1-R16 and the adjacent non-co-located pixels in the motion compensation reference frames R1-R16 to determine the filtering value of the pixel (1601). Fig.16 , co-located pixels in motion compensated reference frames R1-R16 are shown in black, and adjacent non-co-located pixels in motion compensated reference frames R1-R16 are shown in gray and white. Different motion compensated reference frames may use different patterns of non-co-located pixels. For example, only co-located pixels in motion compensated reference frame R1 are used in the temporal filter; non-co-located pixels in motion compensated reference frame R2 form a pattern (1570); non-co-located pixels in motion compensated reference frame R3 form a pattern (1560); non-co-located pixels in motion compensated reference frame R4 form a pattern (1550); non-co-located pixels in motion compensated reference frame R5 form a pattern (1540); non-co-located pixels in motion compensated reference frame R6 form a pattern (1520); non-co-located pixels in motion compensated reference frame R7 form a pattern (1530); non-co-located pixels in motion compensated reference frame R8 form a pattern (1510); non-co-located pixels in motion compensated reference frame R9 form a pattern (1510); non-co-located pixels in motion compensated reference frame R10 form a pattern (1520); non-co-located pixels in motion compensated reference frame R11 form a pattern (1530); non-co-located pixels in motion compensated reference frame R12 form a pattern (1550); non-co-located pixels in motion compensated reference frame R13 form a pattern (1540); non-co-located pixels in motion compensated reference frame R14 form a pattern (1560); non-co-located pixels in motion compensated reference frame R15 form a pattern (1570); and only co-located pixels in motion compensated reference frame R16 are used in the temporal filter.

[0178] Specifically, in some examples, for smaller temporal distance, more non-co-located pixels are used. Each pattern has a set of non-co-located pixels, and the number of non-co-located pixels is determined by m. p Indicates that the pattern can be repeated in motion compensated reference frames 0,..., p times, where n p≤a. In one example, the pattern for the temporal filter formed by non-co-located pixels in the motion compensated reference frame is Fig.15 A mode in .

[0179] In one example, the parameter n max A maximum reference range in which non-local pixels may be used is defined. Outside the maximum reference range, the temporal filter uses only co-located pixels in the motion compensated frame to determine the filtered value of the pixel (1601).

[0180] In some examples, some patterns are associated in pairs. For example, pattern (1520) and pattern (1530) are associated as four point pairs; pattern (1540) and pattern (1550) are associated as vertical and horizontal pairs; pattern (1560) and pattern (1570) are associated as diagonal pairs. In one example, a pair of patterns can be used at adjacent motion compensation reference frames, for example, at motion compensation reference frames Ri and Ri+1. For example, at Fig.16 In , the diagonal pairs are used for R2 and R3, respectively, and the vertical and horizontal pairs are used for R4 and R5, respectively. In another example, a pair of patterns, such as TF±i, can be used at a motion compensation reference frame symmetrical to the TF frame. Fig.16 In the example, the four point pairs are used for R7 (TF-2) and R10 (TF+2) respectively.

[0181] In some embodiments, the spatial position k in the i-th motion compensated reference frame is adjusted using a non-local (n1) weight i The filtering strength of the non-local pixel at , the non-local (n1) weight is denoted as S nl (i,k i ). In some examples, to reduce the complexity of bilateral filtering, when the pixel difference (the difference between the non-local reference pixel in the motion compensated reference frame and the pixel to be filtered in the TF frame) is greater than a given threshold, the non-local reference pixel can be removed (e.g., not considered in the calculation of filtering, with zero as the non-local weight), for example, by ΔI(i, k, k i )>TH 10 It means that, where ΔI(i, k, k i ) represents the spatial position k in the i-th motion compensation reference frame i The pixel difference between the non-local reference pixel at position k and the pixel to be filtered in the TF frame (at spatial position k), while TH 10 is a threshold. In one example, the non-local weight s is determined according to equation (16): nl (i,k i ):

[0182]

[0183] In one example, TH 10 =2 bit-depth >>4, where bit_depth represents the bit depth of the input (eg, original, uncompressed) video sequence.

[0184] In some embodiments, the parameters of the non-co-located reference pixels are, for example, based on the number of points in the pattern (e.g., m p ) of the pattern selection, the number of pattern repetitions (e.g., n p ), the maximum range (for example, n max ) etc., can be used to control the complexity of time domain filtering using non-co-located reference pixels.

[0185] In some embodiments, the filter value of a pixel at spatial position k in the TF frame may be calculated according to equation (17) instead of equation (1):

[0186]

[0187] Among them, I r (i,k i ) is the kth pixel in the i-th motion compensated reference picture; is the number of pixels in the i-th motion compensated reference picture. r (i, a, k, k i ) represents the weight of the pixel, as described in equation (18):

[0188]

[0189] ΔI(i, k, k i ) represents the k-th spatial position of the original TF picture and the i-th motion compensation reference picture i The pixel difference between pixels at a spatial location.

[0190] It should be noted that equation (18) includes various weights corresponding to weight change factors, for example, s n The weights used for the noise level are The weights caused by the block-level signal-to-noise ratio, The weights for low contrast at the block level, and s nl (i,k i ) is used as the weight for non-co-located pixels. In one example, when the weight variation factor is not considered, the corresponding weight can be set to 1.

[0191] Fig.17A flow chart outlining a process (1700) according to an embodiment of the present disclosure is shown. The process (1700) may be used for video processing. In various embodiments, the process (1700) is performed by a processing circuit, such as a processing circuit in an encoding device (901). In some embodiments, the process (1700) is implemented in software instructions, so when the processing circuit executes the software instructions, the processing circuit performs the process (1700). The process starts at (S1701) and proceeds to (S1710).

[0192] At (S1710), one or more parameters of a temporal filter are determined based on video content in an uncompressed video. The uncompressed video includes a sequence of frames (also referred to as a picture). In some examples, the one or more parameters of the temporal filter include at least one of the number of reference frames in a set of reference frames, filter strength, and an enabling / disabling decision of the temporal filter for a block including a first pixel in a first frame. The first frame is a frame to be temporally filtered, and the first pixel is a pixel to be temporally filtered. In some examples, the video content may include at least one of a scene change, a noise level of a frame, a signal-to-noise ratio of a block, and a pixel variance in a block.

[0193] In one example, the number of reference frames in a set of reference frames is determined based on the noise level of the first frame.

[0194] In another example, a frame level filtering strength is determined based on a noise level of the first frame.

[0195] In another example, at least one of a filter strength and a quantization parameter of a block including the first pixel may be based on a signal-to-noise ratio of the block.

[0196] In another example, the decision to enable / disable application of the temporal filter to the block in the first frame is determined based on the complexity of the block.

[0197] At (S1720), a temporal filter having the determined parameters is applied to a first pixel in a first frame to determine a filter value of the first pixel based on the first pixel in the first frame and a second pixel in a set of reference frames of the first frame. The first frame is a frame to be temporally filtered, and the first pixel is a pixel to be temporally filtered.

[0198] In some examples, a set of reference frames in the same scene as the first frame is determined. For a reference frame in the set of reference frames, a motion compensated reference frame is derived based on a motion estimate between the reference frame and the first frame. A filtered value for the first pixel is then calculated based at least in part on a co-located pixel of the first pixel in the motion compensated reference frame.

[0199] Furthermore, in some examples, the filtered value for the first pixel is calculated based on at least one non-co-located pixel for the first pixel in a motion compensated reference frame.

[0200] In one example, the filter value is calculated based on a first number of non-co-located pixels in a first motion compensated reference frame and a second number of non-co-located pixels in a second motion compensated reference frame. The first motion compensated reference frame has a smaller temporal distance to the first frame than the second motion compensated reference frame, and the first number of non-co-located pixels is greater than the second number of non-co-located pixels.

[0201] At (S1730), the filtered video is encoded to generate an encoded video bitstream carrying the filtered video, wherein the filtered video includes a filtered value of a first pixel in a first frame.

[0202] Then, the processing proceeds to (S1799) and terminates.

[0203] The above techniques may be implemented as computer software using computer-readable instructions and physically stored in one or more computer-readable media. Fig.18 A computer system (1800) suitable for implementing certain embodiments of the disclosed subject matter is shown.

[0204] Computer software may be encoded using any suitable machine code or computer language, which may be subjected to assembly, compilation, linking or similar mechanisms to create code comprising instructions that may be executed directly by one or more computer central processing units (CPUs), graphics processing units (GPUs), etc., or through interpretation, microcode execution, etc.

[0205] The instructions may be executed on various types of computers or components thereof, including, for example, personal computers, tablet computers, servers, smartphones, gaming devices, IoT devices, etc.

[0206] Fig.18 The components of the computer system (1800) shown in the example are exemplary in nature and are not intended to impose any limitation on the scope of use or functionality of computer software implementing embodiments of the present disclosure. The configuration of components should not be interpreted as having any dependency or requirement on any one component or combination of components shown in the exemplary embodiment of the computer system (1800).

[0207] The computer system (1800) may include certain human-machine interface input devices. Such human-machine interface input devices may respond to input from one or more human users through, for example, tactile input (e.g., keystrokes, swipes, data glove movements), audio input (e.g., voice, clapping), visual input (e.g., gestures), olfactory input (not shown). The human-machine interface device may also be used to capture certain media that are not necessarily directly related to a person's conscious input, such as audio (e.g., voice, music, ambient sounds), images (e.g., scanned images, photographic images obtained from a still image camera), and video (e.g., two-dimensional video, three-dimensional video including stereoscopic video).

[0208] Input human-machine interface devices may include one or more of the following (only one of each is depicted): keyboard (1801), mouse (1802), trackpad (1803), touch screen (1810), data gloves (not shown), joystick (1805), microphone (1806), scanner (1807), camera (1808).

[0209] The computer system (1800) may also include certain human-machine interface output devices. Such human-machine interface output devices may stimulate one or more human user senses through, for example, tactile output, sound, light, and smell / taste. Such human-machine interface output devices may include tactile output devices (e.g., tactile feedback through a touch screen (1810), a data glove (not shown), or a joystick (1805), but there may also be tactile feedback devices that are not used as input devices), audio output devices (e.g., speakers (1809), headphones (not shown)), visual output devices (e.g., screens (1810), including CRT screens, LCD screens, plasma screens, OLED screens, each with or without touch screen input capabilities, each with or without tactile feedback capabilities - some of which are capable of outputting two-dimensional visual output or more than three-dimensional output through means such as stereo output; virtual reality glasses (not shown), holographic displays, and smoke boxes (not shown)) and printers (not shown).

[0210] The computer system (1800) may also include human-accessible storage devices and their associated media, such as optical media including CD / DVD ROM / RW (1820) with CD / DVD or similar media (1818), thumb drives (1822), removable hard drives or solid-state drives (1823), traditional magnetic media such as tapes and floppy disks (not shown), dedicated ROM / ASIC / PLD devices such as security dongles (not shown), and the like.

[0211] Those skilled in the art should also understand that the term "computer-readable media" used in connection with the presently disclosed subject matter does not include transmission media, carrier waves, or other transient signals.

[0212] The computer system (1800) may also include an interface (1854) to one or more communication networks (1855). The network may be, for example, wireless, wired, optical. The network may also be local, wide, metropolitan, vehicular and industrial, real-time, delay-tolerant, etc. Examples of networks include local area networks such as Ethernet, wireless LAN, cellular networks including GSM, 3G, 4G, 5G, LTE, etc., television wired or wireless wide area digital networks including cable, satellite and terrestrial broadcast television, vehicle and industrial networks including CANBus, etc. Some networks typically require an external network interface adapter connected to some common data port or peripheral bus (1849) (e.g., a USB port of the computer system (1800)); others are typically integrated into the core of the computer system (1800) by connecting to a system bus as described below (e.g., an Ethernet interface in a PC computer system or a cellular network interface in a smartphone computer system). Using any of these networks, the computer system (1800) can communicate with other entities. Such communication may be one-way, receive-only (e.g., broadcast television), one-way, send-only (e.g., CANbus to certain CANbus devices), or two-way, for example, to other computer systems using local or wide area digital networks. As described above, certain protocols and protocol stacks may be used on each of these networks and network interfaces.

[0213] The aforementioned human-machine interface device, human-accessible storage device, and network interface may be attached to the core (1840) of the computer system (1800).

[0214] The core (1840) may include one or more central processing units (CPUs) (1841), graphics processing units (GPUs) (1842), dedicated programmable processing units in the form of field programmable gate arrays (FPGAs) (1843), hardware accelerators (1844) for specific tasks, graphics adapters (1850), etc. These devices, along with read-only memory (ROM) (1845), random access memory (1846), internal mass storage (1847) such as internal non-user accessible hard drives, SSDs, etc., may be connected via a system bus (1848). In some computer systems, the system bus (1848) may be accessible in the form of one or more physical plugs to allow expansion of additional CPUs, GPUs, etc. Peripheral devices may be connected to the core's system bus (1848) directly or via a peripheral bus (1849). In one example, a screen (1810) may be connected to a graphics adapter (1850). The architecture of the peripheral bus includes PCI, USB, etc.

[0215] The CPU (1841), GPU (1842), FPGA (1843) and accelerator (1844) can execute certain instructions, which can be combined to form the above-mentioned computer code. The computer code can be stored in ROM (1845) or RAM (1846). Transition data can also be stored in RAM (1846), while permanent data can be stored in, for example, internal mass storage (1847). Fast storage and retrieval of any storage device can be achieved by using a cache memory, which can be closely associated with one or more CPUs (1841), GPUs (1842), mass storage (1847), ROM (1845), RAM (1846), etc.

[0216] The computer readable medium may have computer codes for performing various computer-implemented operations. The media and computer codes may be specially designed and constructed for the purposes of the present disclosure, or may be of a type well known and available to those skilled in the art of computer software.

[0217] As an example and not limitation, a computer system having architecture (1800), in particular a core (1840), can provide functionality as a result of a processor (including a CPU, GPU, FPGA, accelerator, etc.) executing software contained in one or more tangible computer-readable media. Such a computer-readable medium can be a medium associated with a user-accessible mass storage as described above and certain memories of a core (1840) that are non-transitory, for example, a core internal mass storage (1847) or a ROM (1845). Software implementing various embodiments of the present disclosure can be stored in such a device and executed by the core (1840). Depending on specific needs, the computer-readable medium may include one or more storage devices or chips. The software can cause the core (1840) and in particular the processor therein (including a CPU, GPU, FPGA, etc.) to perform a specific process or a specific part of a specific process described herein, including defining a data structure stored in RAM (1846) and modifying such a data structure according to a software-defined process. In addition or in the alternative, the computer system may provide functionality as a result of logic hardwired or otherwise contained in circuits (e.g., accelerators (1844)) that may operate in place of or in conjunction with software to perform specific processes or specific portions of specific processes described herein. Where appropriate, references to software may include logic and vice versa. Where appropriate, references to computer-readable media may include circuits (e.g., integrated circuits (ICs)) storing software for execution, circuits containing logic for execution, or both. The present disclosure encompasses any suitable combination of hardware and software.

[0218] Appendix A: Abbreviations

[0219] JEM: joint exploration model

[0220] VVC: versatile video coding, multifunctional video coding

[0221] BMS: benchmark set, benchmark set

[0222] MV: Motion Vector

[0223] HEVC: High Efficiency Video Coding, High Efficiency Video Coding

[0224] SEI: Supplementary Enhancement Information, Supplementary Enhancement Information

[0225] VUI:Video Usability Information, video availability information

[0226] GOPs: Groups of Pictures, picture groups

[0227] TUs: Transform Units, Transformation Unit

[0228] PUs: Prediction Units, prediction units

[0229] CTUs: Coding Tree Units, coding tree unit

[0230] CTBs: Coding Tree Blocks, coding tree blocks

[0231] PBs: Prediction Blocks, prediction block

[0232] HRD:Hypothetical Reference Decoder, Hypothetical Reference Decoder

[0233] SNR:Signal Noise Ratio, signal-to-noise ratio

[0234] CPUs: Central Processing Units, central processing units

[0235] GPUs: Graphics Processing Units, Graphics Processing Units

[0236] CRT: Cathode Ray Tube, cathode ray tube

[0237] LCD:Liquid-Crystal Display, liquid crystal display

[0238] OLED: Organic Light-Emitting Diode

[0239] CD: Compact Disc, CD

[0240] DVD: Digital Video Disc, Digital Video Disc

[0241] ROM: Read-Only Memory, read-only memory

[0242] RAM: Random Access Memory, Random Access Memory

[0243] ASIC: Application-Specific Integrated Circuit

[0244] PLD:Programmable Logic Device, Programmable Logic Device

[0245] LAN: Local Area Network, local area network

[0246] GSM: Global System for Mobile communications, Global System for Mobile Communications

[0247] LTE: Long-Term Evolution

[0248] CANBus: Controller Area Network Bus, Controller Area Network Bus

[0249] USB: Universal Serial Bus, Universal Serial Bus

[0250] PCI: Peripheral Component Interconnect, Peripheral Component Interconnect

[0251] FPGA: Field Programmable Gate Areas, field programmable gate area

[0252] SSD: solid-state drive, solid-state drive

[0253] IC: Integrated Circuit

[0254] CU: Coding Unit, coding unit

[0255] Although the present disclosure has described several exemplary embodiments, there are changes, permutations, and various alternative equivalents that fall within the scope of the present disclosure. Therefore, it should be understood that those skilled in the art will be able to design many systems and methods that, although not explicitly shown or described herein, embody the principles of the present disclosure and are therefore within the spirit and scope of the present disclosure.

Claims

1. A video processing method, characterized in that: include: The processor determines parameters of the temporal filter based on video content in the uncompressed video, including, wherein determining a number of reference frames in a set of reference frames in a temporal filter based on a noise level of a first frame in a sequence of frames, the uncompressed video comprising the sequence of frames; or determining a quantization parameter in a time domain filter based on a signal-to-noise ratio of a block including the first pixel in the first frame; or determining whether to skip applying the temporal filter to the block based on whether the block in the first frame is a blank block, in which all pixels have the same value; as well as The processor applies the temporal filter having the determined parameters to the first pixel in the first frame to determine a filtered value for the first pixel based on the first pixel in the first frame and a second pixel in a set of reference frames to the first frame.

2. The method according to claim 1, characterized in that Also includes: The processor encodes a filtered video to generate an encoded video bitstream carrying the filtered video, wherein the filtered video includes the filtered value of the first pixel in the first frame.

3. The method according to claim 1, characterized in that Also includes: determining the set of reference frames in the same scene as the first frame; deriving a motion compensated reference frame for the reference frame in the set of reference frames based on a motion estimate between the reference frame and the first frame; as well as A filtered value for the first pixel is determined based on a co-located pixel for the first pixel in the motion compensated reference frame.

4. The method according to claim 3, characterized in that Also includes: A filtered value for the first pixel is determined based on at least one non-co-located pixel for the first pixel in the motion compensated reference frame.

5. The method according to claim 4, characterized in that Also includes: The filter value is determined based on a first number of non-co-located pixels in a first motion compensated reference frame and a second number of non-co-located pixels in a second motion compensated reference frame, wherein the first motion compensated reference frame has a smaller temporal distance to the first frame than the second motion compensated reference frame, and the first number of non-co-located pixels is greater than the second number of non-co-located pixels.

6. A video processing device, characterized in that: including a processor and memory, The memory is used to store instructions; The processor is configured to call the instructions stored in the memory to implement the method according to any one of claims 1 to 5.

7. A computer-readable storage medium, characterized in that: Contains instructions that, when run on a computer, The computer is enabled to execute the method according to any one of claims 1 to 5.

Images