System, method, and storage medium for smooth mode prediction

Abstract

The various implementations described herein include methods and systems for encoding and decoding video. In one embodiment, a video decoding method includes receiving video data from a video bitstream, the first block being encoded in smooth mode. The method further includes identifying a set of reference samples for the first block and deriving a first predicted value for the first block. The method also includes deriving a refined first predicted value for the first block using a weighted sum of the first reference sample and the first predicted value from the set of reference samples, and decoding the first block based on the refined first predicted value.

Description

Technical Field

[0001] (Related Application) This application claims priority to U.S. Provisional Patent Application No. 63 / 464,155, filed May 4, 2023, entitled "Smooth Modes with Separable Boundary Filtering", and is a continuation of and claims priority to U.S. Patent Application No. 18 / 474,517, filed September 26, 2023, entitled "Systems and Methods for Smooth Mode Predictions".

[0002] The disclosed embodiments generally relate to video coding and include, but are not limited to, systems and methods for smooth mode prediction for video encoding / decoding.

Background Art

[0003] Digital video is supported by various electronic devices such as digital televisions, laptop or desktop computers, tablet computers, digital cameras, digital recording devices, digital media players, video game consoles, smartphones, video teleconferencing devices, video streaming devices. The electronic devices transmit and receive or otherwise communicate digital video data via a communication network and / or store digital video data in a storage device. Since the bandwidth capacity of the communication network is limited and the memory resources of the storage device are limited, video coding may be used to compress video data according to one or more video coding standards before the video data is communicated or stored.

[0004] Multiple video codec standards have been developed. For example, video coding standards include AOMedia Video 1 (AV1), Versatile Video Coding (VVC), Joint Exploration Test Model (JEM), High-Efficiency Video Coding (HEVC / H.265), Advanced Video Coding (AVC / H.264), and Moving Picture Expert Group (MPEG) coding. Video coding generally utilizes prediction methods (e.g., interpretation, intrapretation) that leverage the redundancy inherent in video data. Video coding aims to compress video data into a format that uses a lower bitrate while avoiding or minimizing a decrease in video quality.

[0005] HEVC, also known as H.265, is a video compression standard designed as part of the MPEG-H project. The ITU-T and ISO / IEC published the HEVC / H.265 standard in 2013 (version 1), 2014 (version 2), 2015 (version 3), and 2016 (version 4). Versatile Video Coding (VVC), also known as H.266, is a video compression standard intended as a successor to HEVC. The ITU-T and ISO / IEC published the VVC / H.266 standard in 2020 (version 1) and 2022 (version 2). AV1 is an open video coding format designed as an alternative to HEVC. A valid version 1.0.0, including Errata 1 of its specification, was released on January 8, 2019. [Overview of the project] [Problems that the invention aims to solve]

[0006] As will be explained in more detail below, the smooth prediction modes in the current system (e.g., SMOOTH, SMOOTH-H, and SMOOTH-V in AV1) do not take into account the heterogeneous distribution of available reference samples (e.g., only upper and left reference samples may be available). The systems and methods described herein improve prediction accuracy by biasing (weighting) the predictions using upper and left reference samples. [Means for solving the problem]

[0007] According to several embodiments, a method for video decoding is provided. The method includes (i) receiving video data from a video bitstream, the data comprising a plurality of blocks, the first block being encoded in one of a plurality of smooth modes (e.g., SMOOTH-B, SMOOTH-H, or SMOOTH-V mode); (ii) identifying a set of reference samples for the first block; (iii) deriving a first prediction for the first block; (iv) deriving a refined first prediction for the first block using a weighted sum of the first reference sample from the set of reference samples and the first prediction; and (v) decoding the first block based on the refined first prediction.

[0008] According to several embodiments, a method for video coding is provided. The method includes (i) receiving video data comprising a plurality of blocks, the first block comprising a first block, the first block comprising to be coded in one of a plurality of smooth modes; (ii) identifying a set of reference samples for the first block; (iii) deriving a first predicted value for the first block; (iv) deriving a refined first predicted value for the first block using a weighted sum of the first reference sample of the set of reference samples and the first predicted value; and (v) decoding the first block based on the refined first predicted value.

[0009] According to some embodiments, computing systems are provided, such as streaming systems, server systems, personal computer systems, or other electronic devices. The computing system includes a control circuit and a memory for storing one or more instruction sets. The one or more instruction sets include instructions for performing any of the methods described herein. In some embodiments, the computing system includes encoder components and decoder components (e.g., transcoder components).

[0010] According to some embodiments, a non-transient computer-readable storage medium is provided. The non-transient computer-readable storage medium stores one or more instruction sets for execution by a computing system. One or more instruction sets include instructions for performing any of the methods described herein.

[0011] Accordingly, devices and systems are disclosed using methods for encoding and decoding video. Such methods, devices, and systems may complement or replace conventional methods, devices, and systems for video encoding / decoding.

[0012] The features and advantages described herein are not necessarily exhaustive, and in particular, some additional features and advantages will be apparent to those skilled in the art in consideration of the drawings, specification and claims provided herein. Furthermore, it should be noted that the language used herein has been selected primarily for readability and explanatory purposes and has not necessarily been selected to elaborate on or delineate the subject matter described herein.

[0013] To enable a more detailed understanding of this disclosure, a more detailed description can be provided by referring to the features of various embodiments, some of which are illustrated in the accompanying drawings. However, the accompanying drawings are merely illustrative of the relevant features of this disclosure and should not be considered limiting, as it is possible to recognize other effective features, as a person skilled in the art will understand by reading this disclosure. [Brief explanation of the drawing]

[0014] [Figure 1] Figure 1 is a block diagram illustrating an exemplary communication system according to several embodiments. [Figure 2A] Figure 2A is a block diagram showing exemplary elements of encoder components according to several embodiments. [Figure 2B] Figure 2B is a block diagram showing exemplary elements of decoder components according to several embodiments. [Figure 3] Figure 3 is a block diagram showing exemplary server systems according to several embodiments. [Figure 4A] Figure 4A shows an exemplary coded tree structure according to several embodiments. [Figure 4B] Figure 4B shows an exemplary coded tree structure according to several embodiments. [Figure 4C] Figure 4C shows an exemplary coded tree structure according to several embodiments. [Figure 4D] Figure 4D shows an exemplary coded tree structure according to several embodiments. [Figure 5A] Figure 5A shows an example of a directional intra-predictive mode angle according to several embodiments. [Figure 5B] Figure 5B shows exemplary reference samples to the current block according to several embodiments. [Figure 5C] Figure 5C shows exemplary reference samples to the current block according to several embodiments. [Figure 5D] Figure 5D shows an exemplary weighting of the smooth mode according to several embodiments. [Figure 5E] Figure 5E shows exemplary reference samples to the current block according to several embodiments. [Figure 6A] Figure 6A is a flowchart illustrating exemplary methods for encoding video according to several embodiments. [Figure 6B] Figure 6B is a flowchart illustrating exemplary methods for decoding video according to several embodiments. [Modes for carrying out the invention]

[0015] In general practice, various features illustrated in drawings are not necessarily drawn to scale, and it is possible to use the same reference numerals to represent similar features throughout the specification and drawings.

[0016] This disclosure describes, in particular, a novel smooth prediction mode that can improve prediction accuracy (compared to previous smooth modes) by biasing the prediction using upper and / or left-side reference samples. For example, to predict a sample in the current block using spatially adjacent reference samples, a horizontal prediction value P H This may be derived, and then the reference sample on the left and P H Using a weighted sum with the above, the refined horizontal prediction value P H ' is derived. As another example, the vertical prediction value P V This is derived, and then the upper reference sample and P V Using a weighted sum with the above, the refined horizontal prediction value P V This is derived. In this way, coding accuracy can be improved compared to other smooth prediction modes (for example, artifacts in the decoded video can be reduced).

[0017] (Exemplary systems and devices) Figure 1 is a block diagram showing a communication system 100 according to several embodiments. The communication system 100 includes a source device 102 and a plurality of electronic devices 120 (e.g., electronic devices 120-1 to 120-m) that are coupled to communicate with one or more networks. In some embodiments, the communication system 100 is a streaming system for use in video-enabled applications such as video conferencing applications, digital TV applications, and media storage and / or distribution applications.

[0018] Source device 102 includes a video source 104 (e.g., a camera component or a media storage device) and an encoder component 106. In some embodiments, the video source 104 is a digital camera (e.g., configured to generate an uncompressed video sample stream). The encoder component 106 generates one or more encoded video bitstreams from the video stream. The video stream from video source 104 may have a larger data volume compared to the encoded video bitstream 108 generated by the encoder component 106. Because the encoded video bitstream 108 has a smaller data volume (less data) compared to the video stream from the video source, the encoded video bitstream 108 requires less bandwidth to transmit and less storage space to store compared to the video stream from video source 104. In some embodiments, source device 102 does not include the encoder component 106 (e.g., it is configured to transmit uncompressed video data to a network 110).

[0019] One or more networks 110 represent any number of networks that transmit information between the source device 102, the server system 112, and / or the electronic device 120, for example, including wired and / or wireless communication networks. One or more networks 110 may exchange data over circuit switching channels and / or packet switching channels. Typical networks include telecommunications networks, local area networks, wide area networks, and / or the Internet.

[0020] One or more networks 110 include a server system 112 (e.g., a distribution / cloud computing system). In some embodiments, the server system 112 is or includes a streaming server (configured to store and / or distribute video content, e.g., an encoded video stream from a source device 102). The server system 112 includes a coder component 114 (configured to encode and / or decode video data, e.g., video data). In some embodiments, the coder component 114 includes an encoder component and / or a decoder component. In various embodiments, the coder component 114 is instantiated as hardware, software, or a combination thereof. In some embodiments, the coder component 114 is configured to decode an encoded video bitstream 108 and re-encode the video data using different encoding standards and / or methodologies to produce encoded video data 116. In some embodiments, the server system 112 is configured to produce multiple video formats and / or encodings from the encoded video bitstream 108.

[0021] In some embodiments, the server system 112 functions as a Media-Aware Network Element (MANE). For example, the server system 112 may be configured to prune an encoded video bitstream 108 to adapt potentially different bitstreams to one or more of the electronic devices 120. In some embodiments, the MANE is provided separately from the server system 112.

[0022] Electronic device 120-1 includes a decoder component 122 and a display 124. In some embodiments, the decoder component 122 is configured to decode encoded video data 116 to generate an output video stream that can be rendered on a display or other type of rendering device. In some embodiments, one or more of the electronic devices 120 do not include a display component (e.g., including a media storage device that is communicably coupled to an external display device). In some embodiments, the electronic device 120 is a streaming client. In some embodiments, the electronic device 120 is configured to access a server system 112 to retrieve encoded video data 116.

[0023] The source device and / or multiple electronic devices 120 may be referred to as “terminal devices” or “user devices.” In some embodiments, one or more of the source device 102 and / or electronic devices 120 are instances of a server system, a personal computer, a portable device (e.g., a smartphone, tablet, or laptop), a wearable device, a video conferencing device, and / or other types of electronic devices.

[0024] In an exemplary operation of the communication system 100, source device 102 transmits encoded video bitstream 108 to server system 112. For example, source device 102 may encode a stream of images captured by the source device. Server system 112 receives encoded video bitstream 108 and may decode and / or encode the encoded video bitstream 108 using coder components 114. For example, server system 112 may apply encoding to the video data that is more optimal for network transmission and / or storage. Server system 112 may transmit encoded video data 116 (e.g., one or more encoded video bitstreams) to one or more electronic devices 120. Each electronic device 120 may decode the encoded video data 116 to restore the video image and optionally display it.

[0025] Figure 2A is a block diagram showing exemplary elements of an encoder component 106 according to several embodiments. The encoder component 106 receives a source video sequence from a video source 104. In some embodiments, the encoder component includes a receiver (e.g., a transceiver) component configured to receive the source video sequence. In some embodiments, the encoder component 106 receives a video sequence from a remote video source (e.g., a video source which is a component of a device different from the encoder component 106). The video source 104 may provide the source video sequence in the form of a digital video sample stream which can be any preferred bit depth (e.g., 8-bit, 10-bit, or 12-bit), any color space (e.g., BT.601 Y CrCB, or RGB), and any preferred sampling structure (e.g., Y CrCb 4:2:0 or Y CrCb 4:4:4). In some embodiments, the video source 104 is a storage device that stores previously captured / prepared video. In some embodiments, the video source 104 is a camera that captures local image information as a video sequence. Video data may be provided as a series of individual images that give motion when viewed sequentially. The images themselves may be organized as a spatial array of pixels, each pixel containing one or more samples depending on the sampling structure, color space, etc., used. Those skilled in the art will readily understand the relationship between pixels and samples. The following description will focus on samples.

[0026] The encoder component 106 is configured to encode and / or compress images from a source video sequence into an encoded video sequence 216 in real time or under other time constraints required by the application. Enforcing an appropriate encoding rate is one function of the controller 204. In some embodiments, the controller 204 controls and is functionally coupled to other functional units, as described below. Parameters set by the controller 204 may include rate control-related parameters (e.g., image skipping, quantizer, and / or lambda values ​​for rate distortion optimization techniques), image size, Group of Pictures (GOP) layout, and maximum motion vector search range. Those skilled in the art will be able to easily identify the other functions of the controller 204, as they may relate to encoder component 106 optimized for a particular system design.

[0027] In some embodiments, the encoder component 106 is configured to operate in a coding loop. In a simplified example, the coding loop includes a source coder 202 (responsible for generating symbols, such as a symbol stream, based on the input image and reference image(s) to be coded) and a (local) decoder 210. The decoder 210 reconstructs the symbols to generate sample data in a manner similar to that of a (remote) decoder (when compression between the symbols and the coded video bitstream is reversible). The reconstructed sample stream (sample data) is input to a reference image memory 208. Since decoding the symbol stream yields bitwise accurate results regardless of the decoder location (local or remote), the contents in the reference image memory 208 are also bitwise accurate between the local and remote encoders. In this way, the predictive unit of the encoder interprets the same sample values ​​as reference image samples that the decoder would interpret when using predictions during decoding. This principle of reference image synchronization (and the resulting drift, for example, if synchronization cannot be maintained due to channel errors) is known to those skilled in the art.

[0028] The operation of decoder 210 can be identical to that of a remote decoder, such as decoder component 122, which is described in detail below in relation to Figure 2B. However, referring briefly to Figure 2B, since symbols are available and the encoding / decoding of symbols to the coded video sequence by the entropicorder 214 and parser 254 may be reversible, the entropy decoding portion of decoder component 122, including buffer memory 252, and parser 254 may not be fully implemented in local decoder 210.

[0029] The decoder techniques described herein, with the exception of analysis / entropy decoding, may exist in substantially the same functional form in the corresponding encoders. For this reason, the subject matter disclosed focuses on decoder operation. A description of encoder techniques can be omitted as it may be the reverse of the decoder techniques. A more detailed explanation is required only in certain areas and is provided below.

[0030] As part of its operation, the source coder 202 may perform motion-compensated predictive coding, which predictively codes the input frame by referencing one or more previously coded frames from a video sequence designated as reference frames. In this scheme, the coding engine 212 codes the difference between the pixel blocks of the input frame and the pixel blocks of the reference frames(s) that may be selected as predictive references(s) for the input frame. The controller 204 may manage the coding operation of the source coder 202, including, for example, setting parameters and subgroup parameters used to encode the video data.

[0031] The decoder 210 decodes the coded video data of a frame that may be designated as a reference frame, based on the symbols generated by the source coder 202. The operation of the coding engine 212 can, advantageously, be a lossy process. When the coded video data is decoded by a video decoder (not shown in Figure 2A), the reconstructed video sequence may be a replica of the source video sequence with some errors. The decoder 210 can replicate the decoding process that may be performed by a remote video decoder on the reference frame and store the reconstructed reference frame in the reference image memory 208. In this scheme, the encoder component 106 locally stores a copy of the reconstructed reference frame having common content as the reconstructed reference frame that will be acquired by the remote video decoder (without transmission errors).

[0032] The predictor 206 may perform a predictive search of the coding engine 212. That is, with respect to a new frame to be coded, the predictor 206 may search the reference image memory 208 for sample data (as candidate reference pixel blocks) or certain metadata such as motion vectors and block shapes of reference images that can function as appropriate predictive references for the new image. The predictor 206 may operate on a per-pixel-block, per-sample-block basis to find an appropriate predictive reference. In some cases, as determined by the search results obtained by the predictor 206, the input image may have predictive references obtained from multiple reference images stored in the reference image memory 208.

[0033] The outputs of all the aforementioned functional units may undergo entropic encoding in the entropicorder 214. The entropicorder 214 converts symbols generated by the various functional units into encoded video sequences by reversibly compressing the symbols according to techniques known to those skilled in the art (e.g., Huffman coding, variable-length coding, and / or arithmetic coding).

[0034] In some embodiments, the output of the entropicorder 214 is coupled to a transmitter. The transmitter may be configured to buffer the coded video sequence generated by the entropicorder 214 and prepare them for transmission over a communication channel 218, which may be a hardware / software link to a storage device that will store the coded video data. The transmitter may be configured to merge the coded video data from the source coder 202 with other data to be transmitted, such as coded audio data and / or auxiliary data streams (source not shown). In some embodiments, the transmitter may transmit additional data along with the coded video. The source coder 202 may include such data as part of the coded video sequence. The additional data may include time / space / SNR enhancement layers, other forms of redundant data such as redundant images and slices, Supplementary Enhancement Information (SEI) messages, Visual Usability Information (VUI) parameter set fragments, etc.

[0035] The controller 204 can manage the operation of the encoder component 106. During coding, the controller 204 may assign a specific coded image type to each coded image, which may affect the coding technique applied to each image. For example, an image may be assigned as an intra-picture (I-picture), a predictive-picture (P-picture), or a bidirectional predictive-picture (B-picture). Intra-pictures can be coded and decoded without using any other frames in the sequence as a source for prediction. Some video codecs enable different types of intra-pictures, including, for example, Independent Decoder Refresh (IDR) images. Those skilled in the art will recognize their variations of I-pictures and their respective uses and characteristics, and therefore will not repeat them here. Predictive-pictures can be coded and decoded using intra-prediction or inter-prediction, which use up to one motion vector and reference index to predict the sample value of each block. Bidirectional predictive-pictures can be coded and decoded using intra-prediction or inter-prediction, which use up to two motion vectors and reference indexes to predict the sample value of each block. Similarly, multiple prediction images can use three or more reference images and associated metadata for the reconstruction of a single block.

[0036] A source image can generally be spatially subdivided into multiple sample blocks (e.g., blocks of 4x4, 8x8, 4x8, or 16x16 samples, respectively), and each block can be coded. Blocks can be coded predictively by referencing other (already coded) blocks, as determined by the coding assignment applied to each image in the block. For example, a block in image I may be coded unpredictably, or it may be coded predictively by referencing already coded blocks of the same image (spatial prediction or intra-prediction). A pixel block in image P may be coded unpredictably via spatial prediction or temporal prediction by referencing one previously coded reference image. A block in image B may be coded unpredictably via spatial prediction or temporal prediction by referencing one or two previously coded reference images.

[0037] Video can be captured chronologically as multiple source images (video images). Intra-image prediction (often abbreviated as intra-prediction) utilizes spatial correlations in a given image, while inter-image prediction utilizes (temporal or other) correlations between images. In one example, a particular image being encoded / decoded, called the current image, is partitioned into blocks. When a block in the current image is similar to a reference block in a previously encoded and buffered reference image in the video, the block in the current image can be encoded by a vector called a motion vector. The motion vector points to a reference block in the reference image and may have a third dimension that identifies the reference image if multiple reference images are used.

[0038] The encoder component 106 may perform coding operations in accordance with a predetermined video coding technology or standard, such as any of those described herein. In these operations, the encoder component 106 may perform various compression operations, including predictive coding operations that utilize temporal and spatial redundancy in the input video sequence. Therefore, the coded video data may conform to the syntax specified by the video coding technology or standard being used.

[0039] Figure 2B is a block diagram showing exemplary elements of a decoder component 122 according to several embodiments. The decoder component 122 in Figure 2B is coupled to channel 218 and display 124. In some embodiments, the decoder component 122 includes a transmitter coupled to a loop filter 256 and configured to transmit data to the display 124 (for example, via a wired or wireless connection).

[0040] In some embodiments, the decoder component 122 includes a receiver coupled to channel 218 and configured to receive data from channel 218 (e.g., via a wired or wireless connection). The receiver may be configured to receive one or more coded video sequences to be decoded by the decoder component 122. In some embodiments, the decoding of each coded video sequence is independent of other coded video sequences. Each coded video sequence may be received from channel 218, which may be a hardware / software link to a storage device that stores coded video data. The receiver may receive coded video data with other data, e.g., coded audio data and / or auxiliary data streams, which may be transferred to each using entities (not shown). The receiver may isolate coded video sequences from other data. In some embodiments, the receiver receives additional (redundant) data with coded video. The additional data may be included as part of the coded video sequence. The additional data may be used by the decoder component 122 to decode the data and / or to reconstruct the original video data with greater precision. Additional data can take the form of, for example, time, space, or SNR enhancement layers, redundant slices, redundant images, or transmission error correction codes.

[0041] According to some embodiments, the decoder component 122 includes a buffer memory 252, a parser 254 (sometimes referred to as an entropy decoder), a scaler / inverse unit 258, an intra-image prediction unit 262, a motion compensation prediction unit 260, an aggregator 268, a loop filter unit 256, a reference image memory 266, and a current image memory 264. In some embodiments, the decoder component 122 is implemented as an integrated circuit, a series of integrated circuits, and / or other electronic circuits. In some embodiments, the decoder component 122 is implemented at least partially in software.

[0042] Buffer memory 252 is coupled between channel 218 and parser 254 (for example, to counteract network jitter). In some embodiments, buffer memory 252 is separate from decoder component 122. In some embodiments, a separate buffer memory is provided between the output of channel 218 and decoder component 122. In some embodiments, in addition to buffer memory 252 within decoder component 122 (for example, configured to handle playout timing), a separate buffer memory is provided outside decoder component 122 (for example, to counteract network jitter). When receiving data from a storage / transfer device with sufficient bandwidth and controllability, or from an asynchronous network, buffer memory 252 may not be required, or can be small. For use in best-effort packet networks such as the Internet, buffer memory 252 may be required, can be relatively large, and advantageously can be adaptively sized, and may be at least partially implemented in an operating system or similar element (not shown) outside decoder component 122.

[0043] The parser 254 is configured to reconstruct symbols 270 from the coded video sequence. The symbols may include, for example, information used to manage the operation of decoder component 122 and / or information for controlling a rendering device such as a display 124. The control information for the rendering device may take the form of, for example, supplemental enhancement information (SEI) messages or video usability information (VUI) parameter set fragments (not shown). The parser 254 parses (entropy decodes) the coded video sequence. The coding of the coded video sequence may follow video coding techniques or standards and may follow principles well known to those skilled in the art, including variable-length coding, Huffman coding, and arithmetic coding with or without context sensitivity. The parser 254 may extract from the coded video sequence a set of at least one subgroup parameters of subgroups of pixels in the video decoder, based on at least one parameter corresponding to a group. Subgroups can include groups of pictures (GOP), images, tiles, slices, macroblocks, coding units (CU), blocks, transform units (TU), and prediction units (PU). Parser 254 can also extract information from the coded video sequence, such as transform coefficients, quantizer parameter values, and motion vectors.

[0044] The reconstruction of symbol 270 may involve multiple different units, depending on the type of coded video image or part thereof (e.g., inter-image and intra-image, inter-block and intra-block) and other factors. Which units are involved and how they are involved can be controlled by subgroup control information analyzed from the coded video sequence by parser 254. The flow of such subgroup control information between parser 254 and the multiple units described below is not depicted for clarity.

[0045] The decoder component 122 can be conceptually subdivided into several functional units, and in some implementations, these units can interact closely with each other and integrate with each other at least partially. However, for clarity, the conceptual subdivision of the functional units is maintained herein.

[0046] The scaler / inverse unit 258 receives quantized transformation coefficients, as well as control information as symbols 270 (such as which transformation to use, block size, quantization coefficients, and / or quantization scaling matrix), from the parser 254. The scaler / inverse unit 258 can output a block containing sample values ​​that can be input to the aggregator 268.

[0047] In some cases, the output samples of the scaler / inverse transform unit 258 relate to intra-coded blocks, i.e., blocks that do not use predictive information from previously reconstructed images but can use predictive information from previously reconstructed portions of the current image. Such predictive information can be provided by the intra-image prediction unit 262. The intra-image prediction unit 262 may generate blocks of the same size and shape as the block being reconstructed, using already reconstructed surrounding information retrieved from the current (partially reconstructed) image from the current image memory 264. The aggregator 268 may, on a sample-by-sample basis, add the predictive information generated by the intra-image prediction unit 262 to the output sample information provided by the scaler / inverse transform unit 258.

[0048] In other cases, the output samples of the scaler / inverse unit 258 relate to an intercoded, potentially motion-compensated block. In such cases, the motion-compensated prediction unit 260 can access the reference image memory 266 to retrieve samples used for prediction. After motion-compensating the retrieved samples according to the symbols 270 related to the block, these samples can be added by the aggregator 268 to the output of the scaler / inverse unit 258 (referred to in this case as residual samples or residual signals) to generate output sample information. The address in the reference image memory 266 from which the motion-compensated prediction unit 260 retrieves the predicted samples may be controlled by a motion vector. The motion vector may be available to the motion-compensated prediction unit 260 in the form of a symbol 270, which may have, for example, X, Y, and reference image components. Motion compensation may also include interpolation of sample values ​​retrieved from the reference image memory 266 when the precise motion vectors of the subsamples are used, a motion vector prediction mechanism, and so on.

[0049] The output samples of the aggregator 268 can undergo various loop filtering techniques in the loop filter unit 256. The video compression technique may include in-loop filtering techniques controlled by parameters contained in the coded video bitstream and made available to the loop filter unit 256 as symbols 270 from the parser 254, but may also respond to metadata obtained during decoding of earlier parts (in decoding order) of the coded image or coded video sequence, and may also respond to previously reconstructed and loop-filtered sample values.

[0050] The output of the loop filter unit 256 can be a sample stream that can be output to a rendering device such as the display 124, or it can be stored in the reference image memory 266 for use in future inter-image prediction.

[0051] Once fully reconstructed, a particular coded image can be used as a reference image for future predictions. Once a coded image is fully reconstructed and identified as a reference image (e.g., by parser 254), the current reference image can become part of the reference image memory 266, and new current image memory can be reallocated before starting the reconstruction of subsequent coded images.

[0052] The decoder component 122 may perform decoding operations according to a predetermined video compression technique that may be documented in a standard, such as one of the standards described herein. The coded video sequence may conform to the syntax specified by the video compression technique or standard being used, in the sense that it is faithful to the syntax of the video compression technique or standard, as specified in the video compression technique documentation or standard, particularly the profile documentation therein. Also, in order to conform to some video compression techniques or standards, the complexity of the coded video sequence may be within a range defined by the level of the video compression technique or standard. In some cases, the level limits the maximum image size, maximum frame rate, maximum reconstruction sample rate (e.g., measured in megasamples per second), maximum reference image size, etc. The limits set by the level may, in some cases, be further limited through the Hypothetical Reference Decoder (HRD) specification and metadata for HRD buffer management signaled in the coded video sequence.

[0053] Figure 3 is a block diagram showing a server system 112 according to several embodiments. The server system 112 includes a control circuit 302, one or more network interfaces 304, memory 314, a user interface 306, and one or more communication buses 312 for interconnecting these components. In some embodiments, the control circuit 302 includes one or more processors (e.g., CPU, GPU, and / or DPU). In some embodiments, the control circuit includes one or more field-programmable gate arrays (FPGAs), hardware accelerators, and / or one or more integrated circuits (e.g., application-specific integrated circuits).

[0054] The network interface(s) 304 may be configured to interface with one or more communication networks (e.g., wireless, wired, and / or optical networks). These communication networks may be local, wide-area, urban, vehicle, and industrial, real-time, latency-tolerant, etc. Examples of communication networks include local area networks such as Ethernet and Wi-Fi; cellular networks such as GSM, 3G, 4G, 5G, and LTE; wired or wireless wide-area digital television networks such as cable TV, satellite TV, and terrestrial broadcast TV; and vehicle and industrial networks such as CANBus. Such communications may be one-way receive only (e.g., broadcast TV), one-way transmit only (e.g., CANbus to a specific CANbus device), or bidirectional (e.g., to other computer systems using local or wide-area digital networks). Such communications may include communications to one or more cloud computing networks.

[0055] The user interface 306 includes one or more output devices 308 and / or one or more input devices 310. The input device(s) 310 may include one or more of the following: a keyboard, mouse, trackpad, touchscreen, data glove, joystick, microphone, scanner, camera, etc. The output device(s) 308 may include one or more of the following: an audio output device (e.g., a speaker), a visual output device (e.g., a display or monitor), etc.

[0056] Memory 314 may include high-speed random-access memory (such as DRAM, SRAM, DDR RAM, and / or other random-access solid-state memory devices) and / or non-volatile memory (such as one or more magnetic disk storage devices, optical disk storage devices, flash memory devices, and / or other non-volatile solid-state memory devices). Memory 314 optionally includes one or more storage devices located remotely from the control circuit 302. Memory 314, or the non-volatile solid-state memory device(s) within Memory 314, includes a non-transient computer-readable storage medium. In some embodiments, Memory 314, or the non-transient computer-readable storage medium of Memory 314, stores the following programs, modules, instructions, and data structures, or subsets or supersets thereof: ● Operating system 316, which includes procedures for handling various basic system services and for performing hardware-dependent tasks. ● A network communication module 318 used to connect the server system 112 to other computing devices via one or more network interfaces 304 (for example, via wired and / or wireless connections). ● Encoding module 320 for performing various functions with respect to encoded and / or decoded data such as video data In some embodiments, the encoding module 320 is an instance of the coder component 114. The encoding module 320 includes, but is not limited to, one or more of the following: Regarding the decoder component 122, a decoding module 322 performs various functions related to decoding the encoded data as described above. o Encoding module 340 for performing various functions related to encoded data as described above with respect to encoder component 106 ●For example, an image memory 352 for storing images and image data for use with the coding module 320. In some embodiments, the image memory 352 includes one or more of the following: a reference image memory 208, a buffer memory 252, a current image memory 264, and a reference image memory 266.

[0057] In some embodiments, the decoding module 322 includes an analysis module 324 (configured to perform the various functions described above with respect to the parser 254, for example), a transformation module 326 (configured to perform the various functions described above with respect to the scalar / inverse transform unit 258, for example), a prediction module 328 (configured to perform the various functions described above with respect to the motion compensation prediction unit 260 and / or intra-image prediction unit 262, for example), and a filter module 330 (configured to perform the various functions described above with respect to the loop filter 256, for example).

[0058] In some embodiments, the coding module 340 includes a coding module 342 (configured to perform the various functions described above with respect to, for example, the source coder 202 and / or the coding engine 212) and a prediction module 344 (configured to perform the various functions described above with respect to, for example, the predictor 206). In some embodiments, the decoding module 322 and / or the coding module 340 includes a subset of the modules shown in Figure 3. For example, a shared prediction module is used by both the decoding module 322 and the coding module 340.

[0059] Each of the identified modules stored in memory 314 corresponds to a set of instructions for performing the functions described herein. The identified modules (e.g., sets of instructions) do not need to be implemented as separate software programs, procedures, or modules; therefore, various subsets of these modules can be combined or rearranged in various embodiments. For example, the coding module 320 may optionally not include separate decoding and coding modules, but rather use the same set of modules to perform both sets of functions. In some embodiments, memory 314 stores a subset of the modules and data structures identified above. In some embodiments, memory 314 stores additional modules and data structures not described above, such as an audio processing module.

[0060] Figure 3 shows a server system 112 according to several embodiments, but it is not a schematic diagram of the structure of the embodiments described herein, but rather is primarily intended as a functional description of the various features that may be present in one or more server systems. In practice, and as will be recognized by those skilled in the art, items shown separately can be combined, and some items can be separated. For example, some items shown separately in Figure 3 can be implemented on a single server, and a single item can be implemented by one or more servers. The actual number of servers used to implement the server system 112, and how functions are allocated among them, will vary from implementation to implementation and, by choice, will depend in part on the amount of data traffic the server system will handle during peak and average usage periods.

[0061] (Examples of coding processes and techniques) The coding processes and techniques described below can be implemented in the devices and systems described above (e.g., source device 102, server system 112, and / or electronic device 120). Figures 4A to 4D show exemplary coding tree structures according to several embodiments. As shown in the first coding tree structure (400) in Figure 4A, some coding techniques (e.g., VP9) use a four-way partition tree from 64x64 levels to 4x4 levels, with some additional constraints on the 8x8 block. In Figure 4A, the partition designated as R can be described as recursive, in that the same partition tree is repeated at lower scales until the lowest 4x4 level is reached.

[0062] As shown in the second coded tree structure (402) in Figure 4B, some coding methods (e.g., AV1) extend the partition tree to a 10-way structure, increasing the maximum size (e.g., referred to as the superblock in VP9 / AV1 parlance) from 128x128. The second coded tree structure includes 4:1 / 1:4 rectangular partitions that are not present in the first coded tree structure. The partition type with three subpartitions in the second row of Figure 4B is referred to as a T-shaped partition. In addition to the coded block size, the coded tree depth can be defined to indicate the partition depth from the root note.

[0063] As an example, a CTU can be partitioned into CUs by using a quad-tree structure represented as a coding tree to adapt to various local characteristics such as HEVC. In some embodiments, the decision of whether to encode an image region using inter-image (time) prediction or intra-image (spatial) prediction is made at the CU level. Each CU can be further partitioned into one, two, or four PUs according to the PU partitioning type. Within a single PU, the same prediction process is applied, and relevant information is transmitted to the decoder on a PU-by-PU basis. After obtaining residual blocks by applying the prediction process based on the PU partitioning type, the CU can be partitioned into TUs according to another quad-tree structure, such as a coding tree for the CU.

[0064] Quad trees with nested multi-type trees using binary and ternary partitioning segmentation structures such as VVC may replace the concept of multiple partition unit types, eliminating the separation of the concepts of CU, PU, ​​and TU, except when necessary for CUs that are too large for the maximum transformation length, for example, and supporting greater flexibility for CU partition shapes. In coded tree structures, CUs can have either a square or rectangular shape. CTUs are initially partitioned by a quadtree (also called a quad tree) structure. Quadtree leaf nodes can be further partitioned by a multi-type tree structure. As shown in the third coded tree structure (404) in Figure 4C, the multi-type tree structure includes four partition types. Multi-type tree leaf nodes are called CUs, and unless a CU is too large for the maximum transformation length, this segmentation is used for prediction and transformation processing without any further partitioning. This means that in most cases, CUs, PUs, and TUs have the same block size in a quad tree with a nested multi-type tree coded block structure. An example of block partitioning for one CTU (406) is shown in Figure 4D, which illustrates an exemplary quad tree with a nested multi-type tree-encoded block structure.

[0065] For directional intra-prediction, several methods support eight directional modes corresponding to angles from 45 to 207 degrees. To leverage greater spatial redundancy in directional textures, directional intra-modes can be extended to angles set at finer granularity. For example, the eight angles may be represented as nominal angles. Eight nominal angles, named V_PRED, H_PRED, D45_PRED, D135_PRED, D113_PRED, D157_PRED, D203_PRED, and D67_PRED, are shown in Figure 5A. As also shown in Figure 5A, for each nominal angle, there may be seven finer angles for a total of 56 directional angles. Predicted angles can be described by adding an angle delta to the nominal intra-angle (e.g., multiplying -3 to 3 by a step size of 3 degrees). To implement directional prediction modes in a common way, the 56 directional intra-prediction modes can be implemented with a unified directional predictor that projects each pixel to a reference subpixel position and interpolates the reference pixels using a two-tap bilinear filter. This directional intra-prediction is sometimes also called unidirectional intra-prediction.

[0066] In some methods, a lookup table is used to map each intra-predicted angle to a horizontal and vertical offset between each pixel in the current block and a reference sample. The offset in the lookup table can be an integer value of the tangent to the angle multiplied by 64 for each intra-predicted angle. For example, 64 is equal to the tangent (45°) multiplied by 64, in which case the tangent (45°) is equal to 1. For example, the associated offset is 64 for an intra-predicted angle of 45 degrees, and the horizontal offset between each pixel in the current block and the reference pixel increases by 1 pixel for every 1 increase in the row number of the pixel.

[0067] Some methods offer omnidirectional smooth intra-prediction modes, such as DC, PAETH, SMOOTH-B (sometimes simply referred to as SMOOTH), SMOOTH-V, and SMOOTH-H. In DC prediction, the average of the left and upper adjacent samples can be used as the predictor for the block to be predicted. In PAETH prediction, the upper, left, and upper-left reference samples may be taken, and the value closest to a given value (e.g., upper + left - upper-left) is set as the predictor for the pixel to be predicted. Figure 5B shows the positions of the upper sample 514, the left sample 518, and the upper-left sample 516 of the current pixel (or patch or subblock) within the current block. In SMOOTH-B, SMOOTH-V, and SMOOTH-H modes, the block can be predicted using vertical or horizontal quadratic interpolation, or by averaging in both directions.

[0068] To capture the decaying spatial correlation with references on edges, filter-intramodes can be used for rumor blocks. In some methods, five filter-intramodes are defined, each represented by a set of eight 7-tap filters, which reflect the correlation between a pixel in a 4x2 patch (subblock) and its seven adjacent neighboring pixels. In this way, the weighting coefficients of the 7-tap filters are position-dependent. For example, in the case of an 8x8 block, as shown in Figure 5C, it can be divided into eight 4x2 patches. In Figure 5C, the patches are indicated as B0, B1, B2, B3, B4, B5, B6, and B7. For each patch, seven neighboring pixels (indicated by R0-R7) are used to predict the pixels in the current patch. In the case of patch B0, all neighboring pixels have already been reconstructed. Except for other patches, some of the neighboring pixels may not be reconstructed. In that case, the predicted value of the most recent neighboring pixel may be used as a reference. For example, since not all adjacent pixels in patch B7 may be reconstructed, predicted samples of adjacent pixels (e.g., B5 and B6) are used instead.

[0069] In some techniques, the SMOOTH-V and SMOOTH-H modes generate predicted values by using interpolation along the vertical and horizontal directions respectively, and the SMOOTH-B mode generates a predicted value by using the average of the interpolation results along both directions. The upper, left, upper-right, and lower-left adjacent reconstructed sample values can be represented as T, L, TR, and BL respectively. The predicted sample values in the three modes can be calculated as follows.

[0070] P H (x,y)=w(x)×L+(1-w(x))×TR Equation 1 - SMOOTH-H mode P V (x,y)=w(y)×T+(1-w(y))×BL Equation 2 - SMOOTH-V mode P(x,y)=(P H (x,y)+P V (x,y)) / 2 Equation 3 - SMOOTH-B mode

[0071] Where x represents the horizontal coordinate of the predicted sample within the prediction block, y represents the vertical coordinate of the predicted sample within the prediction block, w(x) and w(y) are weighting values derived based on the coordinate values, and P H , P V、 and P represent the prediction blocks of the SMOOTH-H, SMOOTH-V, and SMOOTH-B modes respectively. FIG. 5D is a diagram showing the prediction processes of the SMOOTH-V and SMOOTH-H modes, and w(y) and w(x) are non-linear weighting values derived based on the vertical and horizontal coordinates in the SMOOTH-V and SMOOTH-H modes respectively. The weights can be stored in a look-up table.

[0072] In some systems, smooth prediction modes (e.g., SMOOTH-B, SMOOTH-H, and SMOOTH-V modes described above) do not take into account the heterogeneous distribution of available reference samples (e.g., only upper and left-side reference samples may be available) or the nonlinear weighting distribution of available reference samples. Therefore, the prediction accuracy of these smooth modes may be reduced compared to modes that are more heavily weighted by the upper and left-side reference samples. The systems and methods described below can improve prediction accuracy compared to the smooth prediction modes shown in Equation 1-3 above. The methods and processes described below may be used separately or in any order. In the following description, a mode is referred to as a directional mode if it generates prediction samples according to a given prediction direction.

[0073] As used herein, a left-hand reference sample refers to a reference sample located with vertical coordinates within the minimum and maximum vertical coordinates of the current block (e.g., current block 522), as shown by section 528 on the left side of Figure 5E. An upper-hand reference sample refers to a reference sample located with horizontal coordinates within the minimum and maximum horizontal coordinates of the current block, as shown by section 524 on the upper side of Figure 5E. A lower-left-hand reference sample refers to a reference sample located with vertical coordinates greater than the maximum vertical coordinate of the current block, as shown by section 530 on the lower left side of Figure 5E. An upper-right-hand reference sample refers to a reference sample located with horizontal coordinates greater than the maximum horizontal coordinate of the current block, as shown by section 526 on the upper right side of Figure 5E. An upper-left-hand reference sample refers to a reference sample located with horizontal coordinates smaller than the minimum horizontal coordinate of the current block and vertical coordinates smaller than the minimum vertical coordinate of the current block, as shown by section 532 on the upper left side of Figure 5E.

[0074] Figure 6A is a flowchart illustrating a method 600 for encoding video according to several embodiments. The method 600 can be implemented in a computing system (e.g., a server system 112, a source device 102, or an electronic device 120) having a control circuit and a memory for storing instructions for execution by the control circuit. In some embodiments, the method 600 is implemented by executing instructions stored in the memory of the computing system (e.g., memory 314).

[0075] The system receives video data containing multiple blocks, including a first block (602), the first block to be encoded in a smooth mode (e.g., SMOOTH-B, SMOOTH-H, or SMOOTH-V). The system identifies a set of reference samples for the first block (604). The system derives a first prediction for the first block (606). The system derives a refined first prediction for the first block using a weighted sum of the first reference sample from the set of reference samples and the first prediction (608). The system encodes the first block based on the refined first prediction (610). For example, the system reconstructs the first block based on the refined first prediction, evaluates the smooth modes based on the reconstructed first block, and selects a smooth mode for encoding the first block according to the evaluation (e.g., the smooth mode has the lowest error).

[0076] Figure 6B is a flowchart illustrating a method 650 for decoding video according to several embodiments. The method 650 can be implemented in a computing system (e.g., a server system 112, a source device 102, or an electronic device 120) having a control circuit and a memory for storing instructions for execution by the control circuit. In some embodiments, the method 650 is implemented by executing instructions stored in the memory of the computing system (e.g., memory 314).

[0077] The system receives video data from a video bitstream, which includes multiple blocks, including a first block (652), the first block being encoded in smooth mode (e.g., SMOOTH-B, SMOOTH-H, or SMOOTH-V). The system identifies a set of reference samples for the first block (654). The system derives a first prediction for the first block (656). The system derives a refined first prediction for the first block using a weighted sum of the first reference sample from the set of reference samples and the first prediction (658). The system decodes the first block based on the refined first prediction (660).

[0078] Figures 6A and 6B illustrate several logical stages in a specific order, but the order-independent stages may be rearranged, and other stages may be combined or separated. Since several rearrangements or other groupings not specifically mentioned are obvious to those skilled in the art, the rearrangements and groupings presented herein are not exhaustive. Furthermore, it should be recognized that the stages may be implemented in hardware, firmware, software, or any combination thereof.

[0079] In some embodiments, a horizontal prediction value P is used to predict a sample in the current block using a spatially adjacent reference sample. H This is derived first, and then the reference sample on the left (for example, a reference sample with the same vertical coordinates) and P H Using a weighted sum with the above, the refined horizontal prediction value P H ' is derived. In some embodiments, the refined horizontal prediction value P H ' is used for the current sample prediction (for example, corresponding to SMOOTH-H mode). In some embodiments, the vertical prediction value P V This is derived, and then the upper reference sample (for example, a reference sample with the same horizontal coordinates) and P V Using a weighted sum with the above, the refined horizontal prediction value P V' is derived. In some embodiments, the refined vertical prediction value P V ' is used for the current sample prediction (for example, corresponding to SMOOTH-V mode). In some embodiments, the combined (final) predicted value P is P H 'and P V It is derived as a weighted sum of '. In some embodiments, the combined predicted value P is used for the current sample prediction (for example, corresponding to SMOOTH-B mode).

[0080] In some embodiments, the horizontal prediction value P H This is derived using a weighted sum of the left-side reference sample and one or more upper (and / or upper-right) reference samples. For example, the weighted sum may be based on bilinear interpolation filtering. In some embodiments, the vertical predictive value P V This is derived using a weighted sum of the upper reference sample and one or more left (and / or lower left) reference samples. For example, the weighted sum may be based on bilinear interpolation filtering. In some embodiments, the left and upper reference samples are P H and / or P V The values ​​are filtered before they are generated. For example, the reference samples on the left and top are P H and P V Before generating a value, it may be filtered using a smoothing filter such as a Gaussian filter or a bidirectional filter, in which case the coefficients of the smoothing filter are non-negative integers.

[0081] In some embodiments, the refined horizontal prediction value P H ' is derived using equation 4 below.

[0082] P H '=(w L ·L+(Nw L )·P H +r) / N Equation 4 - Refined horizontal prediction values

[0083] In the formula, L is the sample on the left or the sample in the lower left, and w L is derived using the horizontal coordinate values ​​of the current sample, where N is a predetermined value (e.g., an integer that is a power of 2, such as 2, 4, 8, 16, 32, 64, 128, 256, 512, or 1024), and r is a rounding offset (e.g., equal to 0.5·N). In some embodiments, w L This is derived as K >> ((x << 1) >> s), where K is a predetermined value (e.g., 16, 32, or 64), x is the horizontal coordinate of the current sample that will be predicted, s is a scaling factor based on the block size (e.g., s is equal to (log2(W) + log2(H) + 2) >> 2), and W and H are the width and height of the block, respectively.

[0084] In some embodiments, the refined vertical prediction value P V ' is derived using equation 5 below.

[0085] P V '=(w T ·T+(Nw T )·P V +r) / N Equation 5 - Refined vertical prediction

[0086] In the formula, T is the upper sample or the upper right sample, and w T This is derived using the vertical coordinate values ​​of the current sample. In some embodiments, w T This is derived as K >> ((y << 1) >> s), where y is the vertical coordinate of the current sample that will be predicted.

[0087] In some embodiments, the combined (final) predicted value P is P H 'and P V It is derived as the average of '. In some embodiments, P is P H 'and P V It is derived as a weighted average of ', in which case the weights depend on the width and height of the block.

[0088] In some embodiments, the new modes discussed above are applied in conjunction with the SMOOTH, SMOOTH-V, and SMOOTH-H modes of AV1 (corresponding, for example, to Equations 1-3). In some embodiments, the new modes discussed above replace the SMOOTH, SMOOTH-V, and SMOOTH-H modes of AV1. In some embodiments, the new modes discussed above are signaled as additional modes. For example, the mode may be a new mode in an intra-mode list. In another example, the mode may be signaled with the SMOOTH-B, SMOOTH-V, and SMOOTH-H modes. For example, a smooth mode index may be signaled to indicate whether a new mode or an existing mode is being used.

[0089] In some embodiments, when calculating the predicted samples for a new SMOOTH-B mode (or blend mode), the division (and / or right shift) operation is moved to the final derivation step. For example, the SMOOTH-B mode is calculated as shown in Equation 6-8 below, where L is the left sample or lower left sample and T is the upper sample or upper right sample.

[0090] P H '=(w L ·L+(Nw L )·P H ) Equation 6 - Refined horizontal prediction without division P V '=(w T ·T+(Nw T )·P V ) Equation 7 - Refined vertical prediction without division P=(P H '+P V '+r) / (2·N) Equation 8 - Combined Predicted Values

[0091] In some embodiments, P H and P VThe division (and / or right shift) operations used in the calculation are also moved to the final derivation step of the combined (final) predictor, as shown in Equations 9-13 below. For example, during the calculation of the inner part, a common value may be multiplied so that each predictor has the same divider (or shift value).

[0092] P V =(T·(H-1-y)+BL·(y+1))·W) Equation 9 - Vertical Prediction P V '=(w T ·W·H·T+(Nw T )·P V ) Equation 10 - Refined vertical prediction without division P H =(L·(W-1-x)+TR·(x+1))·H Equation 11 - Horizontal prediction value P H '=(w L ·W·H·L+(Nw L )·P H ) Equation 12 - Refined horizontal prediction without division P=(P H '+P V '+r) / (2·N·W·H) Equation 13 - Combined Predicted Values

[0093] In equations 9-13, r is the rounding offset (e.g., equal to N·W·H). In equations 9-13, multiplication by W or H can be a left shift by log2(W) or log2(H), and division by (2·N·W·H) can be a right shift by (1+log2(W)+log2(H)+log2(N)).

[0094] TIFF2026515575000002.tif113170

[0095] TIFF2026515575000003.tif35170

[0096] (A1) In one embodiment, several embodiments include a method for video encoding (e.g., method 600). In some embodiments, the method is implemented in a computing system having memory and control circuits (e.g., server system 112). In some embodiments, the method is implemented in a coding module (e.g., coding module 320). In some embodiments, the method is implemented in a source coding component (e.g., source coder 202), a coding engine (e.g., coding engine 212), and / or an entropicorder (e.g., entropicorder 214). The method includes (i) receiving video data containing a plurality of blocks, the first block being encoded in smooth mode; (ii) identifying a set of reference samples for the first block; (iii) deriving a first prediction for the first block; (iv) deriving a refined first prediction for the first block using a weighted sum of the first reference sample and the first prediction for the set of reference samples; and (v) decoding the first block based on the refined first prediction.

[0097] (A2) In some embodiments of A1, the first predicted value is the horizontal predicted value, and the first reference sample is the left reference sample. In some embodiments, the weighted sum of the left reference sample and the horizontal predicted value uses the weights for the left reference sample based on the horizontal coordinates of the samples in the first block to be encoded.

[0098] (A3) In some embodiments of A1, the first predicted value is the vertical predicted value, and the first reference sample is the upper reference sample. In some embodiments, the weighted sum of the upper reference sample and the vertical predicted value uses the weights for the upper reference sample based on the vertical coordinates of the samples in the first block to be encoded.

[0099] (A4) In some embodiments of A1 to A3, the method includes (i) deriving a second predicted value for a first block; (ii) deriving a refined second predicted value for the first block using a weighted sum of a second reference sample from a set of reference samples and the second predicted value; and (iii) deriving a combined predicted value using a weighted sum of the refined first predicted value and the refined second predicted value, the first block being decoded using the combined predicted value. In some embodiments, deriving the combined predicted value using a weighted sum includes using weights based on the block width and block height of the first block.

[0100] (A5) In some embodiments of A1 to A4, the first predicted value for the first block is derived using a weighted sum of the left reference sample and the upper reference sample (for example, using equation 9 or 11).

[0101] (A6) In some embodiments of A1 to A5, the method further includes filtering a set of reference samples to identify a first reference sample.

[0102] (A7) In some embodiments of A1 to A6, the method further includes transmitting the encoded first block over a video bitstream.

[0103] (B1) In other embodiments, some embodiments include a method for video decoding (e.g., method 650). In some embodiments, the method is implemented in a computing system having memory and control circuits (e.g., server system 112). In some embodiments, the method is implemented in a coding module (e.g., coding module 320). In some embodiments, the method is implemented in a parser (e.g., parser 254), a motion prediction component (e.g., motion compensation prediction unit 260), and / or an intra-prediction component (e.g., intra-image prediction unit 262). The method includes (i) receiving video data (e.g., an encoded video sequence) from a video bitstream, the first block being encoded in smooth mode; (ii) identifying a set of reference samples for the first block; (iii) deriving a first predicted value for the first block; (iv) deriving a refined first predicted value for the first block using a weighted sum of the first reference sample from the set of reference samples and the first predicted value; and (v) decoding the first block based on the refined first predicted value. For example, the smooth mode is SMOOTH-H mode, SMOOTH-V mode, or a combined (SMOOTH-B) mode. In some embodiments, a first syntax element in the video bitstream is used to signal the smooth mode.

[0104] (B2) In some embodiments of B1, the first predicted value is a horizontal predicted value and the first reference sample is a left-side reference sample. For example, to predict a sample in the current block using a spatially adjacent reference sample, the horizontal predicted value P H This is derived first, followed by the reference sample on the left and P H The final predicted value P is derived using a weighted sum of these factors. In some embodiments, the refined first predicted value is derived using one of equations 4, 6, 12, or 17.

[0105] (B3) In some embodiments of B2, the weighted sum of the left reference sample and the horizontal prediction value uses the weights for the left reference sample based on the horizontal coordinates of the first block sample that will be predicted. For example, w L This can be derived as K >> ((x << 1) >> s), where K is a given value, x is the predicted horizontal coordinate of the current sample, and s is a scaling factor based on the block size. For example, s may be equal to (log2(W) + log2(H) + 2) >> 2, where W and H are the width and height of the block, respectively.

[0106] (B4) In some embodiments of B1, the first predicted value is the vertical predicted value and the first reference sample is the upper reference sample. For example, to predict a sample in the current block using a spatially adjacent reference sample, the vertical predicted value P V This is derived first, followed by the upper reference sample and P V The final predicted value P is derived using a weighted sum of these factors. In some embodiments, the refined first predicted value is derived using one of equations 5, 7, 10, or 15.

[0107] (B5) In some embodiments of B4, the weighted sum of the upper reference sample and the vertical prediction value uses the weights for the upper reference sample based on the vertical coordinates of the first block sample that will be predicted. For example, w T This can be derived as K >> ((y << 1) >> s), where K is a given value, y is the vertical coordinate of the current sample that will be predicted, and s is a scaling factor based on the block size. For example, s may be equal to (log2(W) + log2(H) + 2) >> 2, where W and H are the width and height of the block, respectively.

[0108] (B6) In some embodiments of B1 to B5, the method includes (i) deriving a second predicted value for a first block, (ii) deriving a refined second predicted value for the first block using a weighted sum of a second reference sample from a set of reference samples and the second predicted value, and (iii) deriving a combined predicted value using a weighted sum of the refined first predicted value and the refined second predicted value, the first block being decoded using the combined predicted value. For example, to predict a sample in the current block using spatially adjacent reference samples, a horizontal predicted value P H This is derived first, and then the reference sample on the left (for example, a reference sample with the same vertical coordinates) and P H Using a weighted sum with the above, the refined horizontal prediction value P H ' is derived. In this example, the vertical predicted value P V This is derived, and then the upper reference sample (for example, a reference sample with the same horizontal coordinates) and P V Using a weighted sum with the above, the refined horizontal prediction value P V ' is derived. Next, in this example, the final predicted value P is P H 'and P V It is derived as a weighted sum with '.

[0109] (B7) In some embodiments of B6, deriving a combined predicted value using a weighted sum involves using weights based on the block width and block height of the first block. For example, the combined predicted value P is P H 'and P V It is derived as a weighted average of ', in this case the weights depend on the width and height of the block. In some embodiments, the combined predicted value P is P H 'and P V It is derived as the average of '.

[0110] (B8) In some embodiments of any one of B1 to B7, the first predicted value for the first block is derived using a weighted sum of the left reference sample and the upper reference sample (e.g., using Equation 9 or 11). For example, the horizontal predicted value P H is derived using a weighted sum of the left reference sample and one (or more) of the upper (and / or upper right) reference samples. An exemplary weighted sum uses bilinear interpolation filtering. As another example, the vertical predicted value P V is derived using a weighted sum of the upper reference sample and one (or more) of the left (and / or lower left) reference samples.

[0111] (B9) In some embodiments of any one of B1 to B8, the method further includes filtering a set of reference samples to identify a first reference sample. For example, the left and upper reference samples may be filtered before generating the P H and P V values. In some embodiments, the left and upper reference samples are filtered using a smoothing filter, such as a Gaussian filter or a bidirectional filter, before generating the P H and P V values. For example, all the coefficients of the smoothing filter may be non-negative integers.

[0112] In another aspect, some embodiments include a computing system (e.g., server system 112) that includes a control circuit (e.g., control circuit 302) and a memory (e.g., memory 314) coupled to the control circuit, the memory storing one or more sets of instructions configured to be executed by the control circuit, the one or more sets of instructions including instructions for performing any of the methods described herein (e.g., A1 to A7 and B1 to B9 above).

[0113] In yet another embodiment, some embodiments include a non-transient computer-readable storage medium that stores one or more sets of instructions for execution by a control circuit of a computing system, the one or more sets of instructions including instructions for performing any of the methods described herein (e.g., A1-A7 and B1-B9 above).

[0114] In this specification, terms such as "first," "second," etc., may be used to describe various elements, but it should be understood that these elements should not be limited by these terms. These terms are used solely to distinguish one element from another.

[0115] The terms used herein are for the purpose of describing specific embodiments only and are not intended to limit the scope of the claims. Where used in the description of embodiments and the appended claims, the singular forms “a,” “an,” and “the” are intended to include the plural form unless the context clearly indicates otherwise. Where used herein, the term “and / or” should also be understood to refer to and encompass all possible combinations of one or more of the associated enumerated items. Where used herein, the terms “comprises” and / or “comprising” specify the presence of the described features, integers, steps, actions, elements, and / or components, but should also be understood not to exclude the presence or addition of one or more other features, integers, steps, actions, elements, components, and / or groups thereof.

[0116] As used herein, the term "if" can be interpreted, depending on the context, as meaning "when," "upon," "in response to determining," "in accordance with a determination," or "in response to detecting" that the stated premise is true. Similarly, the phrase "[if it is determined that the stated premise is true]," "[if the stated premise is true]," or "[when the stated premise is true]" can be interpreted, depending on the context, as meaning "in response to determining," "in response to determining," "in accordance with a determination," "in response to detecting," or "in response to detecting."

[0117] The foregoing description is provided with reference to specific embodiments for illustrative purposes. However, the above exemplary discussion is not intended to be exhaustive or to limit the claims to the exact form disclosed. In light of the above teachings, many modifications and variations are possible. The embodiments have been selected and described so as to be available to those skilled in the art in the best way to illustrate the principles of operation and practical applications.

Claims

1. A video decoding method implemented in a computing system having memory and one or more processors, Receiving video data from a video bitstream, the data comprising a plurality of blocks including a first block, wherein the first block is encoded in one of a plurality of smooth modes. Identifying a set of reference samples for the first block described above, To derive a first predicted value for the first block, To derive a refined first prediction for the first block using a weighted sum of the first reference sample from the set of reference samples and the first prediction, wherein neither the first weight for the first reference sample nor the second weight for the first prediction is equal to zero. Decoding the first block based on the refined first predicted value, Methods that include...

2. The method according to claim 1, wherein the first predicted value is a horizontal predicted value and the first reference sample is the left reference sample.

3. The method according to claim 2, wherein the weighted sum of the left-side reference sample and the horizontal predicted value uses weights for the left-side reference sample based on the horizontal coordinates of the first block sample that will be predicted.

4. The method according to claim 1, wherein the first predicted value is a vertical predicted value and the first reference sample is an upper reference sample.

5. The method according to claim 4, wherein the weighted sum of the upper reference sample and the vertical prediction value uses weights for the upper reference sample based on the vertical coordinates of the first block sample that will be predicted.

6. To derive a second predicted value for the first block, Using a weighted sum of a second reference sample from the set of reference samples and the second predicted value, a refined second predicted value for the first block is derived. Using the weighted sum of the refined first predicted value and the refined second predicted value, a combined predicted value is derived. It further includes, The method according to claim 1, wherein the first block is decoded using the combined predicted values.

7. The method according to claim 6, wherein deriving the combined predicted values ​​using the weighted sum comprises using weights based on the block width and block height of the first block.

8. The method according to claim 1, wherein the first predicted value for the first block is derived using a weighted sum of the left reference sample and the upper reference sample.

9. The method according to claim 1, further comprising filtering a set of reference samples to identify the first reference sample.

10. Control circuit and Memory and One or more sets of instructions stored in the memory and configured for execution by the control circuit, wherein the one or more sets of instructions are Receiving video data from a video bitstream, the data comprising a plurality of blocks including a first block, wherein the first block is encoded in one of a plurality of smooth modes. Identifying a set of reference samples for the first block described above, To derive a first predicted value for the first block, To derive a refined first prediction for the first block using a weighted sum of the first reference sample from the set of reference samples and the first prediction, wherein neither the first weight for the first reference sample nor the second weight for the first prediction is equal to zero. Decoding the first block based on the refined first predicted value, One or more sets of instructions, including instructions for performing the following: A computing system equipped with [the following features].

11. The computing system according to claim 10, wherein the first predicted value is a horizontal predicted value, and the first reference sample is a left-side reference sample.

12. The computing system according to claim 10, wherein the first predicted value is a vertical predicted value and the first reference sample is an upper reference sample.

13. One or more sets of the aforementioned instructions are To derive a second predicted value for the first block, Using a weighted sum of a second reference sample from the set of reference samples and the second predicted value, a refined second predicted value for the first block is derived. Using the weighted sum of the refined first predicted value and the refined second predicted value, a combined predicted value is derived. Further including instructions for carrying out, The computing system according to claim 10, wherein the first block is decoded using the combined predicted values.

14. The computing system according to claim 13, wherein deriving the combined predicted values ​​using the weighted sum comprises using weights based on the block width and block height of the first block.

15. The computing system according to claim 10, wherein the first predicted value for the first block is derived using a weighted sum of the left reference sample and the upper reference sample.

16. A non-transient computer-readable storage medium storing one or more sets of instructions configured for execution by a computing device having a control circuit and memory, wherein the one or more sets of instructions are: Receiving video data from a video bitstream, the data comprising a plurality of blocks including a first block, wherein the first block is encoded in one of a plurality of smooth modes. Identifying a set of reference samples for the first block described above, To derive a first predicted value for the first block, To derive a refined first prediction for the first block using a weighted sum of the first reference sample from the set of reference samples and the first prediction, wherein neither the first weight for the first reference sample nor the second weight for the first prediction is equal to zero. Decoding the first block based on the refined first predicted value, A non-transient, computer-readable storage medium containing instructions for performing a certain action.

17. The non-transient computer-readable storage medium according to claim 16, wherein the first predicted value is a horizontal predicted value and the first reference sample is a left-side reference sample.

18. The non-transient computer-readable storage medium according to claim 16, wherein the first predicted value is a vertical predicted value and the first reference sample is an upper reference sample.

19. One or more sets of the aforementioned instructions are To derive a second predicted value for the first block, Using a weighted sum of a second reference sample from the set of reference samples and the second predicted value, a refined second predicted value for the first block is derived. Using the weighted sum of the refined first predicted value and the refined second predicted value, a combined predicted value is derived. Further including instructions for carrying out, The non-transient computer-readable storage medium according to claim 16, wherein the first block is decoded using the combined predicted values.

20. The non-transient computer-readable storage medium according to claim 16, wherein the first predicted value for the first block is derived using a weighted sum of the left reference sample and the upper reference sample.

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