Decoding method and apparatus, encoding method and apparatus, and corresponding encoder and decoder

Abstract

The present application relates to the technical field of encoding and decoding. Provided are a decoding method and apparatus, an encoding method and apparatus, and a corresponding encoder and decoder. The decoding method comprises: acquiring a bitstream of an image to be decoded, wherein the image to be decoded comprises a block to be decoded; when a reference block corresponding to the block to be decoded cannot be acquired, acquiring first data, wherein the first data is obtained by means of adjusting second data on the basis of a parameter of an adjustment operation, the second data is preset reference data, the parameter of the adjustment operation comprises at least one of a first adjustment parameter and a second adjustment parameter, the first adjustment parameter is used for adjusting the data precision of the second data, and the second adjustment parameter is used for adjusting the data range of the second data; then, on the basis of the first data, performing intra prediction on the block to be decoded, so as to obtain predicted data of the block to be decoded; and finally, on the basis of the predicted data, decoding the bitstream, so as to obtain reconstructed data of the block to be decoded. By means of the method, the bandwidth occupied by a bitstream can be reduced, thereby improving the encoding and decoding performance.

Description

Decoding methods, encoding methods and devices, and corresponding encoders and decoders

[0001] This application claims priority to Chinese patent application filed on January 24, 2025, with application number 202510123846.2 and entitled "Decoding method, encoding method and apparatus, corresponding encoder and decoder", the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application relates to the field of encoding and decoding technology, and in particular to a decoding method, encoding method and apparatus, and corresponding encoder and decoder. Background Technology

[0003] Digital video capabilities can be incorporated into a wide variety of devices, including digital television, digital live broadcasting systems, wireless broadcasting systems, personal digital assistants (PDAs), laptops or desktop computers, tablets, e-book readers, digital cameras, digital recording devices, digital media players, video game devices, video game consoles, cellular or satellite radio phones (so-called "smartphones"), video conferencing devices, video streaming devices, and the like. Digital video devices implement video compression techniques, such as those described in standards defined by MPEG-2, MPEG-4, ITU-T H.263, ITU-T H.264 / MPEG-4 Part 10 High-Level Video Coding (AVC), the H.265 / HEVC video coding standard, and extensions to such standards. By implementing such video compression techniques, video devices can transmit, receive, encode, decode, and / or store digital video information more efficiently.

[0004] Video compression techniques perform spatial (intra-image) prediction to reduce or remove redundancy inherent in video sequences. For block-based video coding, video stripes (i.e., video frames or portions of video frames) can be divided into several image blocks, which may also be referred to as tree blocks, coding units (CUs), and / or coding nodes.

[0005] However, the current encoding and decoding methods have low efficiency and need to be improved. Summary of the Invention

[0006] To address the aforementioned technical problems, this application provides a decoding method, an encoding method and apparatus, and corresponding encoders and decoders, which can improve encoding and decoding efficiency.

[0007] In a first aspect, embodiments of this application provide a decoding method, the method comprising: acquiring a bitstream of an image to be decoded, the image to be decoded including a block to be decoded; when a reference block corresponding to the block to be decoded is unavailable, acquiring first data, the first data being obtained by adjusting second data based on parameters of an adjustment operation, the second data being preset reference data, the parameters of the adjustment operation including at least one of a first adjustment parameter and a second adjustment parameter, the first adjustment parameter being used to adjust the data precision of the second data, and the second adjustment parameter being used to adjust the data range of the second data; performing intra-frame prediction on the block to be decoded based on the first data to obtain predicted data of the block to be decoded; and decoding the bitstream based on the predicted data to obtain reconstructed data of the block to be decoded.

[0008] In this embodiment, when the reference block for the block to be decoded is unavailable, second data is obtained as the reference block corresponding to the intra-prediction mode of the block to be decoded. The second data is then adjusted based on the parameters of the aforementioned adjustment operation to obtain first data. This first data, after adjustment, matches the data of the block to be decoded, thus serving as the reference block for intra-prediction. In this way, when performing intra-prediction on the block to be decoded, the data dimension of the block to be decoded is the same as the data dimension of the first data serving as the reference block, thereby improving the accuracy of the intra-prediction prediction data and consequently improving decoding accuracy and efficiency. Simultaneously, it reduces excessive bandwidth consumption caused by the transmission bitstream.

[0009] Meanwhile, the first adjustment parameter can be used to adjust the data precision of the second data, so that the adjusted second data (i.e. the first data) can retain higher precision data for intra-frame prediction and decoding, thereby improving the accuracy of the prediction data of intra-frame prediction.

[0010] Furthermore, the second adjustment parameter can adjust the data range of the second data to a suitable range, for example, from a negative data range to a positive data range. Thus, when the second data (i.e., the first data) after range adjustment by this second parameter is represented (e.g., in binary data), only the data value needs to be represented, without occupying at least one bit (e.g., a sign bit) to indicate that the data is negative. This reduces the data bit width of the reference block used for intra-frame prediction, improving prediction and decoding efficiency.

[0011] Based on the first aspect, in some possible implementations, the parameters of the above-mentioned adjustment operation are obtained from the bitstream.

[0012] Based on the first aspect, in some possible implementations, the block to be decoded undergoes wavelet transform and adjustment operations during encoding.

[0013] In this embodiment, since the block to be encoded corresponding to the block to be decoded has undergone wavelet transform and adjustment operations during encoding, the same adjustment operation can be performed on the preset reference data when the reference block of the block to be decoded is unavailable. This ensures that the data dimension of the block to be decoded is the same as the data dimension of the reference data (here, the first data) used for intra-frame prediction of the block to be decoded, thereby ensuring the accuracy of the prediction data for intra-frame prediction of the block to be decoded. At the same time, the data bit width of the reference block is reduced, thereby improving the decoding efficiency.

[0014] Based on the first aspect, in some possible implementations, the reference block of the block to be decoded may not be available. Examples may include the following situations:

[0015] For example, a reference block for the block to be decoded may exist in the decoded block in the current frame. However, the reference block existing in the current frame is not the reference block corresponding to the block to be decoded in the intra-frame prediction mode, so the reconstruction data of the reference block corresponding to the block to be decoded in the intra-frame prediction mode cannot be obtained.

[0016] Alternatively, there may be a reference block in the current frame that corresponds to the intra-prediction mode of the block to be decoded. However, this reference block has not been decoded and reconstructed before the block to be decoded, so the reconstruction data of the reference block cannot be obtained (which is also a scenario where the reference block of the block to be decoded is unavailable).

[0017] Alternatively, any block in the current frame (whether or not it is decoded) is not the reference block of the block to be decoded corresponding to the intra-prediction mode of that frame, and the reconstructed data of the reference block corresponding to the block to be decoded in that intra-prediction mode cannot be obtained (which is also a scenario where the reference block of the block to be decoded is unavailable).

[0018] Based on the first aspect, in some possible implementations, the order of the parameters of the adjustment operation used when the second data is adjusted is the same as the order of the parameters used when the block to be decoded is encoded.

[0019] In this way, the order of the adjustment operations of the preset reference data (e.g., the order of use of the first adjustment parameter and the second adjustment parameter) is consistent with the order of the adjustment operations performed on the block to be decoded. This ensures that the first data obtained after adjusting the second data can be used as the reference data for intra-frame prediction of the block to be decoded, thereby ensuring that the data of the block to be decoded is in the same dimension as the first data, thus ensuring the accuracy of intra-frame prediction.

[0020] Based on the first aspect, in some possible implementations, the first data is obtained by adjusting the second data sequentially according to the first adjustment parameter and the second adjustment parameter.

[0021] In the embodiments of this application, the preset reference data (i.e., the second data) is adjusted in terms of precision first, followed by range adjustment. Precision adjustment improves the precision of the adjusted data, allowing the adjusted block to be decoded or the second data to retain higher precision for intra-frame prediction and decoding, thereby improving the accuracy of the intra-frame prediction data. Performing range adjustment after precision adjustment ensures that the block to be decoded and the first data used for intra-frame prediction are of the same dimension.

[0022] Based on the first aspect, in some possible implementations, the first data is a left shift operation of the second data according to the first adjustment parameter.

[0023] Because left-shifting can improve the precision of the adjusted data, the adjusted block to be decoded or the second data can retain higher precision data for intra-frame prediction and decoding, thereby improving the accuracy of the predicted data for intra-frame prediction.

[0024] Based on the first aspect, in some possible implementations, the first data is the second data with an added offset according to the second adjustment parameter.

[0025] Based on the first aspect, in some possible implementations, the first data is obtained by adjusting the second data according to the first adjustment parameter (e.g., left shift operation), and then adjusting the second data after the adjustment operation according to the second adjustment parameter again (e.g., increasing the offset).

[0026] In this embodiment, both the block to be decoded and the second data are first left-shifted before the offset is increased. Since left-shifting improves the precision of the adjusted data, the adjusted block to be decoded or the second data retains higher precision for intra-frame prediction and decoding, thereby improving the accuracy of the intra-frame prediction data. Furthermore, increasing the offset after the left-shift operation ensures that the block to be decoded and the first data used for intra-frame prediction are on the same dimension.

[0027] Based on the first aspect, in some possible implementations, the second adjustment parameter is specifically used to adjust the data range of the second data to a positive data range.

[0028] In this embodiment, the data range of the second data can be adjusted from a negative data range to a positive data range. This positive data range indicates that the minimum value within the range is zero or a positive number. Thus, when the first data obtained after range adjustment using the second adjustment parameter is represented (e.g., in binary data), only the data value needs to be represented, without needing to occupy at least one bit (e.g., a sign bit) to represent that the data is negative. This reduces the data bit width used as a reference block during intra-frame prediction, improving prediction and decoding efficiency.

[0029] Based on the first aspect, in some possible implementations, the parameters of the adjustment operation are related to at least one of the following: the type of wavelet transform; and the data length of the block to be decoded before the wavelet transform and adjustment operation during encoding.

[0030] In the embodiments of this application, the parameters of the adjustment operation under different scenarios can be determined based on the different types of wavelet transforms and the data length of the block to be decoded before the wavelet transform and adjustment operation during encoding. This improves the diversity of adjustment parameters and allows for better precision and range adjustment under different scenarios. This improves the precision of the adjusted data while reducing the data bit width of the adjusted data, thereby improving prediction efficiency and decoding efficiency.

[0031] Based on the first aspect, in some possible implementations, the block to be decoded is the block data in the wavelet coefficients of the low-frequency subband obtained by wavelet transform of the original image during encoding.

[0032] In this embodiment, considering that the size of the low-frequency subband output by the wavelet transform is 1 / 4 of the image before the wavelet transform (e.g., the image to be decoded), by performing intra-frame prediction on the block data in the low-frequency subband, the amount of data to be decoded can be reduced compared to performing intra-frame prediction and decoding on the original image, thereby improving the efficiency of intra-frame prediction and decoding. Considering that the data distribution of the low-frequency subband is more uniform than that of the high-frequency subband output by the wavelet transform, by performing intra-frame prediction and decoding on the block data in the low-frequency subband using the method of this embodiment, the accuracy of intra-frame prediction can be improved, thereby improving the decoding accuracy. Furthermore, the decoded block data of the low-frequency subband can be used for display after decoding; for example, the displayed image of the low-frequency subband can be a thumbnail of the original image.

[0033] Based on the first aspect, in some possible implementations, the reference block is determined based on the position of the block to be decoded and the intra-prediction mode of the block to be decoded.

[0034] In some embodiments, the intra-frame prediction mode may include at least one of the following: direct current (DC) mode, vertical mode, horizontal mode, planar mode, and cross-component linear model (CCLM) mode.

[0035] In some embodiments, the intra-prediction mode (also referred to as the first intra-prediction mode) on the chroma component can be one of the following: vertical mode, horizontal mode, DC mode, and CCLM mode.

[0036] In some embodiments, the intra-prediction mode (also referred to as the second intra-prediction mode) on the luminance component can be one of the following: vertical mode, horizontal mode, DC mode, and planar mode.

[0037] In this embodiment, based on the position of the block to be decoded, it is determined that there is no reference block for the block to be decoded in the intra-prediction mode of that block. Therefore, preset reference data is used as the reference data for intra-prediction of the current block. However, after adjustment, the preset reference data becomes inconsistent with the data dimension of the current block. Therefore, by performing the same adjustment operation on the preset reference data, the adjusted second data can be made consistent with the data dimension of the current block, allowing intra-prediction to be performed in the same dimension, thus improving the accuracy of the prediction data for the current block.

[0038] Based on the first aspect, in some possible implementations, the image to be decoded is a low-frequency subband image.

[0039] Based on the first aspect, in some possible implementations, the block to be decoded is block data in the wavelet coefficients of the low-frequency subband.

[0040] Secondly, embodiments of this application provide an encoding method, which includes: when a reference block corresponding to a block to be encoded in an image to be encoded is unavailable, acquiring first data, wherein the first data is obtained by adjusting second data based on parameters of an adjustment operation, the second data being preset reference data, and the parameters of the adjustment operation including at least one of a first adjustment parameter and a second adjustment parameter, wherein the first adjustment parameter is used to adjust the data precision of the second data, and the second adjustment parameter is used to adjust the data range of the second data; performing intra-frame prediction on the block to be encoded based on the first data to obtain predicted data of the block to be encoded; and encoding the block to be encoded based on the predicted data to obtain a bitstream.

[0041] Based on the second aspect, in some possible implementations, the image to be encoded is a low-frequency subband image.

[0042] Based on the second aspect, in some possible implementations, the block to be encoded is obtained after wavelet transform and the adjustment operation.

[0043] Based on the second aspect, in some possible implementations, if the reference block corresponding to the block to be encoded is not encoded or the reference block corresponding to the block to be encoded does not exist, then the reference block corresponding to the block to be encoded is unavailable. The situation where the reference block corresponding to the block to be encoded is unavailable can be referred to the description in the first aspect.

[0044] Based on the second aspect, in some possible implementations, the order of the parameters of the adjustment operation used when the second data is adjusted is the same as the order of the parameters used when the block to be encoded is subjected to the adjustment operation.

[0045] Based on the second aspect, in some possible implementations, the above-mentioned adjustment of the second data based on the first adjustment parameter can be: performing a left shift operation on the second data based on the first adjustment parameter.

[0046] Based on the second aspect, in some possible implementations, the above-mentioned adjustment of the second data based on the second adjustment parameter can be: increasing the offset of the second data based on the second adjustment parameter.

[0047] Based on the second aspect, in some possible implementations, the first data is obtained by adjusting the second data sequentially according to the first adjustment parameter and the second adjustment parameter.

[0048] Based on the second aspect, in some possible implementations, the first data is obtained by shifting the second data to the left according to the first adjustment parameter, and by adding an offset to the second data after the left shift according to the second adjustment parameter.

[0049] Based on the second aspect, in some possible implementations, the second adjustment parameter is specifically used to adjust the data range of the block to be encoded and the second data to a positive data range.

[0050] Based on the second aspect, in some possible implementations, the parameters of the adjustment operation are related to at least one of the following: the type of wavelet transform; and the data length of the block to be encoded prior to the wavelet transform and the adjustment operation.

[0051] Based on the second aspect, in some possible implementations, the block to be encoded is the block data in the wavelet coefficients of the low-frequency subband obtained after wavelet transform of the image to be encoded.

[0052] Based on the second aspect, in some possible implementations, the reference block is determined based on the position of the block to be encoded and the intra-prediction mode of the block to be encoded.

[0053] Based on the second aspect, in some possible implementations, the parameters of the above-mentioned adjustment operation are encoded into the above-mentioned bitstream.

[0054] The effect of the encoding method is similar to that of the first aspect and any of the implementation methods described above, and will not be repeated here.

[0055] Thirdly, embodiments of this application provide a decoding apparatus, which may include: an acquisition module, configured to acquire a bitstream of an image to be decoded, the image to be decoded including a block to be decoded; the acquisition module is further configured to acquire first data when a reference block corresponding to the block to be decoded is unavailable, the first data being obtained by adjusting second data based on parameters of an adjustment operation, the second data being preset reference data, the parameters of the adjustment operation including at least one of a first adjustment parameter and a second adjustment parameter, the first adjustment parameter being used to adjust the data precision of the second data, and the second adjustment parameter being used to adjust the data range of the second data; a prediction module, configured to perform intra-frame prediction on the block to be decoded based on the first data to obtain predicted data of the block to be decoded; and a decoding module, configured to decode the bitstream based on the predicted data to obtain reconstructed data of the block to be decoded.

[0056] Fourthly, embodiments of this application provide an encoding apparatus, comprising: an acquisition module, configured to acquire first data when a reference block corresponding to the block to be encoded in the image to be encoded is unavailable, the first data being obtained by adjusting second data based on parameters of an adjustment operation, the second data being preset reference data, the parameters of the adjustment operation including at least one of a first adjustment parameter and a second adjustment parameter, the first adjustment parameter being used to adjust the data precision of the second data, and the second adjustment parameter being used to adjust the data range of the second data; a prediction module, configured to perform intra-frame prediction on the block to be encoded based on the first data to obtain predicted data of the block to be encoded; and an encoding module, configured to encode the block to be encoded based on the predicted data to obtain a bitstream.

[0057] Fifthly, a system for distributing bitstreams is provided, the system comprising: at least one storage medium for storing a bitstream generated according to the method of the first or second aspect and any embodiment thereof; and a streaming media device for acquiring the bitstream from the at least one storage medium and transmitting the bitstream, wherein the streaming media device includes a content server or a content distribution server.

[0058] In a sixth aspect, a transcoding system is provided, comprising: at least one storage medium for storing a bitstream generated according to the method of the second aspect or any embodiment thereof; and a transcoding device for acquiring the bitstream from the at least one storage medium and transcoding the bitstream.

[0059] In one embodiment, the transcoding device can convert the bitstream into MPEG-4 Part 4 (MP4), Matroska Video (MKV), Audio Video Interleave (AVI), Digital Audio Video (DAV), etc., without limitation.

[0060] In a seventh aspect, this application provides an apparatus comprising: one or more processors; a memory for storing one or more programs; wherein when the one or more programs are executed by the one or more processors, the one or more processors implement the method as described in the first aspect or any embodiment of the first aspect.

[0061] Eighthly, this application provides an apparatus comprising: one or more processors; a memory for storing one or more programs; wherein when the one or more programs are executed by the one or more processors, the one or more processors implement the method as described in the second aspect or any embodiment of the second aspect above.

[0062] Ninthly, this application provides a computer-readable storage medium including a computer program that, when executed on a device, causes the device to perform the method described in the first aspect or any embodiment of the first aspect.

[0063] In a tenth aspect, this application provides a computer-readable storage medium including a computer program that, when executed on a device, causes the device to perform the method described in the second aspect or any of the embodiments of the second aspect.

[0064] In one aspect, this application provides a computer program that, when executed by a device, is used to perform the method described in the first aspect or any embodiment of the first aspect, or to perform the method described in the second aspect or any embodiment of the second aspect.

[0065] In a twelfth aspect, this application provides a computer program product comprising computer program code that, when executed on a device, causes the device to perform the method described in the first aspect or any embodiment of the first aspect, or to perform the method described in the second aspect or any embodiment of the second aspect.

[0066] In a thirteenth aspect, this application provides a bitstream generated according to the method in the second aspect or any embodiment of the second aspect described above.

[0067] In a fourteenth aspect, this application provides a computer-readable storage medium storing a bitstream generated according to the method in the second aspect or any embodiment of the second aspect described above.

[0068] In a fifteenth aspect, an apparatus for storing a bitstream is provided, the apparatus comprising: a transceiver unit and a storage unit, the transceiver unit being configured to receive a bitstream generated according to the method described in accordance with the second aspect or any embodiment thereof, and the storage unit being configured to store the bitstream.

[0069] In a sixteenth aspect, an apparatus for transmitting a bitstream is provided, the apparatus comprising: a storage unit and a transceiver unit, the storage unit being configured to store a bitstream generated according to the method described in accordance with the second aspect or any embodiment thereof, and the transceiver unit being configured to transmit the bitstream.

[0070] In a seventeenth aspect, an encoder is provided. The encoder includes a processing circuit that implements the steps described in the second aspect or any embodiment of the second aspect.

[0071] In an eighteenth aspect, a decoder is provided. The decoder includes processing circuitry that implements the steps described in the first aspect or any embodiment of the first aspect. Attached Figure Description

[0072] Figure 1A is a schematic block diagram of a video encoding and decoding system provided in an embodiment of this application;

[0073] Figure 1B is a schematic block diagram of a video decoding system provided in an embodiment of this application;

[0074] Figure 2 is a schematic block diagram of an encoder provided in an embodiment of this application;

[0075] Figure 3 is a schematic block diagram of a decoder provided in an embodiment of this application;

[0076] Figure 4 is a schematic diagram of the structure of a video decoding device provided in an embodiment of this application;

[0077] Figure 5 is a schematic diagram of the structure of a device provided in an embodiment of this application;

[0078] Figure 6 is a schematic block diagram of an encoder based on wavelet transform provided in an embodiment of this application;

[0079] Figure 7 is a schematic block diagram of a wavelet transform-based decoder provided in an embodiment of this application;

[0080] Figure 8 is a schematic block diagram of an encoder provided in an embodiment of this application;

[0081] Figure 9A is a schematic diagram of sub-graph division provided in an embodiment of this application;

[0082] Figure 9B is a schematic diagram of sub-graph partitioning provided in an embodiment of this application;

[0083] Figure 10 is a schematic diagram of wavelet transform provided in an embodiment of this application;

[0084] Figure 11 is a schematic block diagram of a decoder provided in an embodiment of this application;

[0085] Figure 12 is a schematic block diagram of an encoder provided in an embodiment of this application;

[0086] Figure 13A is a schematic diagram of the structure of an image bitstream provided in an embodiment of this application;

[0087] Figure 13B is a schematic diagram of the structure of an image bitstream provided in an embodiment of this application;

[0088] Figure 14A is a schematic diagram of the structure of an image bitstream provided in an embodiment of this application;

[0089] Figure 14B is a schematic diagram of the structure of an image bitstream provided in an embodiment of this application;

[0090] Figure 15 is a schematic diagram of the structure of an image bitstream provided in an embodiment of this application;

[0091] Figures 16A to 16C are schematic diagrams of the structure of an image bitstream provided in an embodiment of this application;

[0092] Figures 17A and 17B are schematic diagrams of the structure of an image bitstream provided in an embodiment of this application;

[0093] Figure 18 is a schematic block diagram of a decoder provided in an embodiment of this application;

[0094] Figure 19 is a schematic block diagram of a decoder provided in an embodiment of this application;

[0095] Figure 20 is a schematic diagram of an edge-cloud system provided in an embodiment of this application;

[0096] Figure 21 is a schematic diagram of an encoding method provided in an embodiment of this application;

[0097] Figure 22 is a schematic diagram of an encoding method provided in an embodiment of this application;

[0098] Figure 23a is a schematic diagram of an encoding method provided in an embodiment of this application;

[0099] Figure 23b is a schematic diagram of a decoding method provided in an embodiment of this application;

[0100] Figure 24 is a schematic diagram of an application scenario provided by an embodiment of this application;

[0101] Figure 25 is a schematic diagram of a decoding method provided in an embodiment of this application;

[0102] Figure 26 is a schematic diagram of a decoding method provided in an embodiment of this application;

[0103] Figure 27a is a schematic diagram of a decoding device provided in an embodiment of this application;

[0104] Figure 27b is a schematic diagram of an encoding device provided in an embodiment of this application. Detailed Implementation

[0105] The embodiments of this application are described below with reference to the accompanying drawings. In the following description, reference is made to the accompanying drawings, which form part of this application and illustrate specific aspects of the embodiments of this application or to which specific aspects of the embodiments of this application may be used. It should be understood that the embodiments of this application may be used in other aspects and may include structural or logical variations not depicted in the drawings. Therefore, the following detailed description should not be construed in a limiting sense, and the scope of this application is defined by the appended claims. For example, it should be understood that the disclosure of the described methods is equally applicable to corresponding devices or systems for performing the methods, and vice versa. For example, if one or more specific method steps are described, the corresponding device may include one or more units, such as functional units, to perform the described one or more method steps (e.g., one unit performs one or more steps, or multiple units, each performing one or more of multiple steps), even if such one or more units are not explicitly described or illustrated in the drawings. On the other hand, for example, if a specific apparatus is described based on one or more units such as functional units, the corresponding method may include a step to perform the functionality of one or more units (e.g., a step to perform the functionality of one or more units, or multiple steps, each of which performs the functionality of one or more units among a plurality of units), even if such one or more steps are not explicitly described or illustrated in the accompanying drawings. Furthermore, it should be understood that, unless otherwise expressly stated, features of the various exemplary embodiments and / or aspects described herein can be combined with each other.

[0106] The terminology used in the implementation section of this application is for the purpose of explaining specific embodiments of this application only, and is not intended to limit this application.

[0107] The following is a brief introduction to some concepts that may be involved in the embodiments of this application. These concepts are only used to explain the specific embodiments of this application and are not intended to limit this application.

[0108] YUV is a color space model used to represent colors, widely used in image encoding and decoding, video encoding and decoding, digital image processing, television broadcasting, and other fields. YUV separates the luminance information from the chrominance information of an image.

[0109] The three components of YUV:

[0110] Y (luminance) component: Y represents the luminance information of an image, that is, the brightness or darkness of the image. It is obtained by weighting the red, green, and blue color channels according to certain weights. The Y component plays an important role in the sharpness and detail of an image.

[0111] U (chromaticity) component: U represents the chromaticity information of the image, indicating the offset of the blue channel relative to the luminance Y. It measures the change in the blue component.

[0112] V (chromaticity) component: V represents the chromaticity information of the image, indicating the offset of the red channel relative to the luminance Y.

[0113] The residual is the difference between the reconstructed value (or actual value) of a sample or data element and its predicted value.

[0114] A residual block is an M×N residual matrix composed of the residuals corresponding to the coded blocks.

[0115] Dequantization is the process of scaling the quantized residual to obtain the reconstructed residual value.

[0116] A partition divides a set into subsets. Each element in the set belongs to one and only one subset.

[0117] Partition type: The way the subsets obtained from the partition are organized.

[0118] A decoded picture is an image reconstructed by the decoder based on the bitstream.

[0119] Prediction is the specific implementation of the prediction process.

[0120] The prediction process uses previously decoded samples to obtain the predicted value for the current sample.

[0121] Syntax element: The result of parsing data units in a bitstream.

[0122] A bitstream is a binary data stream that encodes all or part of an image sample.

[0123] Video coding generally refers to the processing of a sequence of images that form a video or video sequence. In the field of video coding, the terms "picture," "frame," or "image" can be used synonymously. Video coding is performed on the source side and typically involves processing (e.g., by compression) the raw video images to reduce the amount of data required to represent them, thus enabling more efficient storage and / or transmission. Video decoding is performed on the destination side and typically involves inverse processing relative to the encoder to reconstruct the video images. The combination of encoding and decoding is also known as encoding and decoding.

[0124] A video sequence consists of a series of pictures, which are further divided into slices, and slices into blocks. Video coding is performed on a block-by-block basis. In some newer video coding standards, the concept of a block has been further expanded. For example, the H.264 standard uses macroblocks (MBs), which can be further divided into multiple prediction blocks (partitions) for predictive coding. The High Efficiency Video Coding (HEVC) standard uses basic concepts such as coding units (CUs), prediction units (PUs), and transform units (TUs) to functionally divide various block units, and employs a novel tree-based structure for description. For instance, a CU can be divided into smaller CUs using a quadtree, and these smaller CUs can be further divided, forming a quadtree structure. The CU is the basic unit for partitioning and encoding the image. Similar tree structures exist for PUs and TUs. A PU corresponds to a prediction block and is the basic unit for predictive coding. CUs are further divided into multiple PUs according to partitioning patterns. TU can correspond to a transform block, which is the basic unit for transforming the prediction residual. However, regardless of CU, PU, ​​or TU, they all essentially belong to the concept of block data (or image blocks).

[0125] For example, in HEVC, the CTU is split into multiple CUs using a quadtree structure represented as a coding tree. At the CU level, a decision is made on whether to use inter-picture (temporal) or intra-picture (spatial) prediction to encode picture regions. Each CU can be further split into one, two, or four PUs based on the PU splitting type. The same prediction process is applied within a PU, and relevant information is transmitted to the decoder based on the PU. After obtaining residual blocks by applying the prediction process based on the PU splitting type, the CU can be segmented into transform units (TUs) according to other quadtree structures similar to the coding tree used for CUs. In the latest developments in video compression technology, quadtree and binary tree (QTBT) frame segmentation is used to divide coding blocks. In the QTBT block structure, CUs can be square or rectangular in shape.

[0126] In this paper, for ease of description and understanding, the block of data to be processed in the current image is referred to as the current block. For example, in encoding, the current block refers to the block currently being encoded; in decoding, the current block refers to the block currently being decoded. The decoded current block in the reference image used to predict the current block is called the reference block. That is, the reference block is the block that provides a reference signal for the current block, where the reference signal represents the pixel value within the image block. In the inter-frame prediction process, the block in the reference image that provides the prediction signal for the current block is called the prediction block, where the prediction signal represents the pixel value, sampled value, or sampled signal within the prediction block. For example, after traversing multiple reference blocks, an optimal reference block is found. This optimal reference block will provide prediction for the current block; this block is called the prediction block.

[0127] In lossless video coding, the original video image can be reconstructed, meaning the reconstructed video image has the same quality as the original (assuming no transmission loss or other data loss during storage or transmission). In lossy video coding, further compression is performed, for example, through quantization, to reduce the amount of data required to represent the video image. However, the decoder cannot fully reconstruct the video image, meaning the quality of the reconstructed video image is lower or worse than the original video image.

[0128] The encoding / decoding method of this application embodiment encodes and decodes images or videos on a block-by-block basis.

[0129] In some embodiments, the block to be encoded or the block to be decoded may be an image block or a video block obtained from an image or video.

[0130] In some embodiments, the block to be encoded or the block to be decoded may be an image block or video block within a subgraph obtained by dividing the image or video into subgraphs.

[0131] In some embodiments, the block to be encoded or the block to be decoded can be a block obtained from the transformed data of the image or video to be encoded after transformation processing (e.g., wavelet transform (also known as wavelet forward transform, etc., without limitation).

[0132] This application does not restrict the specific division method of the blocks to be encoded or decoded in an image or video, nor does it restrict the method of obtaining the blocks.

[0133] On the encoding side, the image to be encoded can be a frame from an image or video, a sub-image obtained by dividing a frame from an image or video, an image obtained after transformation (such as wavelet transform), or a sub-image from the transformed image; there are no restrictions here. On the encoding side, "current frame" can represent "image to be encoded," and "current block" can represent "block to be encoded." A frame is a frame of image to be displayed.

[0134] Similarly, the decoding side corresponds to the encoding side. On the decoding side, the image to be decoded can be a frame in an image or video, a sub-image obtained by dividing a frame in an image or video, an image obtained after transformation (such as wavelet transform), or a sub-image in the transformed image; there are no restrictions here. On the decoding side, "current frame" can represent "image to be decoded," and "current block" can represent "block to be decoded." A frame is a frame of image to be displayed.

[0135] Whether on the encoding or decoding side, the reconstructed data (also called the reconstructed value) of a block can be described as a reconstructed block, and the already encoded or decoded block referenced when encoding or decoding the current block can be described as a "reference block".

[0136] Whether on the encoding or decoding side, the prediction data for the current block is also referred to as the prediction block or the prediction value for the current block.

[0137] Whether on the encoding or decoding side, reconstruction is also referred to as refactoring.

[0138] Whether on the encoding or decoding side, the bitstream is also described as a bitstream, etc.

[0139] Whether on the encoding or decoding side, the residual is also referred to as a residual block.

[0140] Whether on the encoding or decoding side, the actual value of the current block is also expressed as the original value of the current block, or the value to be encoded in the current block.

[0141] In the accompanying drawings of the various embodiments described below, dashed boxes or dashed arrows indicate that the step or the data transmitted indicated by the arrow is optional.

[0142] The system architecture used in the embodiments of this application is described below. Referring to FIG1A, FIG1A provides an exemplary schematic block diagram of a video encoding and decoding system 10 used in the embodiments of this application. As shown in FIG1A, the video encoding and decoding system 10 may include a source device 12 and a destination device 14. The source device 12 generates encoded video data, and therefore, the source device 12 may be referred to as a video encoding device. The destination device 14 can decode the encoded video data generated by the source device 12, and therefore, the destination device 14 may be referred to as a video decoding device. Various embodiments of the source device 12, the destination device 14, or both may include one or more processors and memory coupled to the one or more processors. The memory may include, but is not limited to, RAM, ROM, EEPROM, flash memory, or any other media that can be used to store desired program code in the form of computer-accessible instructions or data structures. The source device 12 and the destination device 14 may include a variety of devices, including desktop computers, mobile computing devices, notebook (e.g., laptop) computers, tablet computers, set-top boxes, handsets, televisions, cameras, display devices, digital media players, video game consoles, in-vehicle computers, wireless communication devices, or the like.

[0143] Source device 12 and destination device 14 can communicate via link 13, through which destination device 14 can receive encoded video data from source device 12. Link 13 may include one or more media or devices capable of transmitting encoded video data from source device 12 to destination device 14. In one example, link 13 may include one or more communication media enabling source device 12 to transmit encoded video data to destination device 14 in real time. In this example, source device 12 may modulate the encoded video data according to a communication standard (e.g., a wireless communication protocol) and transmit the modulated video data to destination device 14. The one or more communication media may include wireless and / or wired communication media, such as radio frequency (RF) spectrum or one or more physical transmission lines. The one or more communication media may form part of a packet-based network, such as a local area network, wide area network, or global network (e.g., the Internet). The one or more communication media may include routers, switches, base stations, or other devices facilitating communication from source device 12 to destination device 14.

[0144] The source device 12 includes an encoder 20. Optionally, the source device 12 may also include an image source 16, an image preprocessor 18, and a communication interface 22. In specific implementations, the encoder 20, image source 16, image preprocessor 18, and communication interface 22 may be hardware components or software programs within the source device 12. These are described below:

[0145] Image source 16 may include or be any type of image capture device for, for example, capturing real-world images, and / or any type of image or commentary (for screen content encoding, some text on the screen is also considered as an image to be encoded or part of an image) generation device, such as a computer graphics processor for generating computer-animated images, or any type of device for acquiring and / or providing real-world images, computer-animated images (e.g., screen content, virtual reality (VR) images), and / or any combination thereof (e.g., augmented reality (AR) images). Image source 16 may be a camera for capturing images or a memory for storing images. Image source 16 may also include any type of (internal or external) interface for storing previously captured or generated images and / or acquiring or receiving images. When image source 16 is a camera, image source 16 may be, for example, a local or integrated camera integrated into a source device; when image source 16 is a memory, image source 16 may be a local or integrated memory integrated into a source device. When the image source 16 includes an interface, the interface may be, for example, an external interface for receiving images from an external video source, such as an external image capture device, like a camera, external storage, or an external image generation device, such as an external computer graphics processor, computer, or server. The interface can be any type of interface according to any proprietary or standardized interface protocol, such as a wired or wireless interface, or an optical interface.

[0146] An image can be viewed as a two-dimensional array or matrix of pixels. Pixels in the array are also called sampling points. The number of sampling points in the array or image along the horizontal and vertical directions (or axes) defines the image's size and / or resolution. To represent color, three color components are typically used; that is, an image can be represented as or contain three sampling arrays. For example, in RBG format or color space, an image includes corresponding red, green, and blue sampling arrays. However, in video coding, each pixel is typically represented in a luma / chroma format or color space. For example, for a YUV format image, this includes a luma component indicated by Y (sometimes also indicated by L) and two chroma components indicated by U and V. The luma component Y represents the brightness or grayscale level intensity (e.g., both are the same in a grayscale image), while the two chroma components U and V represent chroma or color information components. Accordingly, a YUV format image includes a luma sampling array of luma sample values ​​(Y) and two chroma sampling arrays of chroma values ​​(U and V). An RGB format image can be converted or transformed to YUV format, and vice versa; this process is also called color transformation or conversion. If the image is black and white, it may only include a luminance sampling array. In this embodiment, the image transmitted from image source 16 to image processor can also be referred to as raw image data 17.

[0147] Image preprocessor 18 is configured to receive raw image data 17 and perform preprocessing on the raw image data 17 to obtain a preprocessed image 19 or preprocessed image data 19. For example, the preprocessing performed by image preprocessor 18 may include retouching, color format conversion (e.g., from RGB format to YUV format), color correction, or noise reduction.

[0148] Encoder 20 (or video encoder 20) is used to receive preprocessed image data 19 and process the preprocessed image data 19 using a relevant prediction mode (such as the prediction mode in the various embodiments herein) to provide encoded image data 21. In some embodiments, encoder 20 may be used to perform the various embodiments described below to implement the encoding method described herein on the encoding side.

[0149] Communication interface 22 can be used to receive encoded image data 21 and transmit the encoded image data 21 via link 13 to destination device 14 or any other device (such as a memory) for storage or direct reconstruction. The other device can be any device used for decoding or storage. Communication interface 22 can, for example, be used to encapsulate the encoded image data 21 into a suitable format, such as data packets, for transmission over link 13.

[0150] Destination device 14 includes decoder 30. Optionally, destination device 14 may also include communication interface 28, image post-processor 32, and display device 34. These are described below:

[0151] Communication interface 28 can be used to receive encoded image data 21 from source device 12 or any other source, such as a storage device, for example, an encoded image data storage device. Communication interface 28 can be used to transmit or receive encoded image data 21 via link 13 between source device 12 and destination device 14 or via any type of network, such as a wired or wireless connection, any type of network, such as a wired or wireless network or any combination thereof, or any type of private and public network, or any combination thereof. Communication interface 28 can be used, for example, to decapsulate data packets transmitted by communication interface 22 to obtain encoded image data 21.

[0152] Both communication interface 28 and communication interface 22 can be configured as unidirectional or bidirectional communication interfaces, and can be used, for example, to send and receive messages to establish connections, acknowledge and exchange any other information related to the communication link and / or data transmission, such as encoded image data transmission.

[0153] Decoder 30 (or video decoder 30) is used to receive encoded image data 21 and provide decoded image data 31 or decoded image 31 (the structural details of decoder 30 will be further described below based on FIG3, FIG4 or FIG5). In some embodiments, decoder 30 can be used to perform the various embodiments described below to implement the decoding method described in this application on the decoding side.

[0154] Image post-processor 32 is used to perform post-processing on decoded image data 31 (also referred to as reconstructed image data) to obtain post-processed image data 33. The post-processing performed by image post-processor 32 may include: color format conversion (e.g., from YUV format to RGB format), color correction, retouching or resampling, or any other processing, and may also be used to transmit the post-processed image data 33 to display device 34.

[0155] Display device 34 is used to receive post-processed image data 33 to display an image to, for example, a user or viewer. Display device 34 can be or may include any class of displays for presenting reconstructed images, such as integrated or external displays or monitors. For example, displays may include liquid crystal displays (LCDs), organic light emitting diode (OLED) displays, plasma displays, projectors, micro-LED displays, liquid crystal on silicon (LCoS), digital light processors (DLP), or any other class of displays.

[0156] Although Figure 1A illustrates source device 12 and destination device 14 as separate devices, device embodiments may also include the functionality of both source device 12 and destination device 14, or both; that is, the functionality of source device 12 or its corresponding features and the functionality of destination device 14 or its corresponding features. In such embodiments, the same hardware and / or software, or separate hardware and / or software, or any combination thereof, may be used to implement the functionality of source device 12 or its corresponding features and the functionality of destination device 14 or its corresponding features.

[0157] Both encoder 20 and decoder 30 can be implemented as any of a variety of suitable circuits, such as one or more microprocessors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), discrete logic, hardware, or any combination thereof. If the technology is implemented in part in software, the device can store the software instructions in a suitable non-transitory computer-readable storage medium, and one or more processors can be used to execute the instructions in hardware to perform the technology of this disclosure. Any of the foregoing (including hardware, software, combinations of hardware and software, etc.) can be considered as one or more processors.

[0158] In some cases, the video encoding and decoding system 10 shown in Figure 1A is merely an example, and the technology of this application can be applied to video encoding setups (e.g., video encoding or video decoding) that do not necessarily involve any data communication between the encoding and decoding devices. In other instances, data may be retrieved from local storage, streamed over a network, etc. The video encoding device may encode the data and store it in storage, and / or the video decoding device may retrieve the data from storage and decode it. In some instances, encoding and decoding are performed by devices that do not communicate with each other but only encode data to storage and / or retrieve data from storage and decode the data.

[0159] Referring to FIG1B, FIG1B is an illustrative diagram of an example of a video decoding system 40 including the encoder 20 of FIG2 and / or the decoder 30 of FIG3 according to an exemplary embodiment. The video decoding system 40 can implement various combinations of technologies of the embodiments of this application. In the illustrated embodiment, the video decoding system 40 may include an imaging device 41, an encoder 20, a decoder 30 (and / or a video encoder / decoder implemented by logic circuitry of a processing unit 46), an antenna 42, one or more processors 43, one or more memories 44, and a display device 45.

[0160] As shown in Figure 1B, the imaging device 41, antenna 42, processing unit 46, logic circuit, encoder 20, decoder 30, processor 43, memory 44, and display device 45 are capable of communicating with each other. As discussed, although encoder 20 and decoder 30 are used as examples to describe the video decoding system 40, in different instances, the video decoding system 40 may contain only encoder 20 or only decoder 30.

[0161] In some instances, antenna 42 can be used to transmit or receive encoded video data streams. Additionally, in some instances, display device 45 can be used to present video data. In some instances, logic circuitry can be implemented using processing unit 46. Processing unit 46 can include an ASIC, graphics processor, general-purpose processor, etc. Video decoding system 40 can also include an optional processor 43, which can similarly include an ASIC, graphics processor, general-purpose processor, etc. In some instances, logic circuitry can be implemented in hardware, such as dedicated video encoding hardware, while processor 43 can be implemented in general-purpose software, operating system, etc. Furthermore, memory 44 can be any type of memory, such as volatile memory (e.g., static random access memory (SRAM), dynamic random access memory (DRAM), etc.) or non-volatile memory (e.g., flash memory, etc.). In a non-limiting instance, memory 44 can be implemented using cache memory. In some instances, logic circuitry can access memory 44 (e.g., for implementing an image buffer). In other instances, the logic circuitry and / or processing unit 46 may include memory (e.g., cache, etc.) for implementing image buffers, etc.

[0162] In some instances, the encoder 20 implemented via logic circuitry may include (e.g., implemented via processing unit 46 or memory 44) an image buffer and (e.g., implemented via processing unit 46) a graphics processing unit. The graphics processing unit may be communicatively coupled to the image buffer. The graphics processing unit may include the encoder 20 implemented via logic circuitry to implement various modules discussed with reference to Figure 2 and / or any other encoder system or subsystem described herein. The logic circuitry may be used to perform various operations discussed herein.

[0163] In some instances, decoder 30 may be implemented via logic circuitry in a similar manner to implement the various modules discussed in reference to decoder 30 of Figure 3 and / or any other decoder system or subsystem described herein. In some instances, the logic circuitry-implemented decoder 30 may include an image buffer (implemented via processing unit 46 or memory 44) and a graphics processing unit (e.g., implemented via processing unit 46). The graphics processing unit may be communicatively coupled to the image buffer. The graphics processing unit may include decoder 30 implemented via logic circuitry to implement the various modules discussed in reference to Figure 3 and / or any other decoder system or subsystem described herein.

[0164] In some instances, antenna 42 can be used to receive an encoded stream of video data. As discussed herein, the encoded stream may contain data related to encoded video frames, indicators, index values, mode selection data, etc., such as data related to code segmentation (e.g., transform coefficients or quantized transform coefficients, optional indicators, and / or data defining code segmentation). Video decoding system 40 may also include a decoder 30 coupled to antenna 42 for decoding the encoded stream. Display device 45 is used to display the video frames.

[0165] It should be understood that, referring to the examples described for encoder 20 in the embodiments of this application, decoder 30 can be used to perform the reverse process. Regarding signaling syntax elements, decoder 30 can be used to receive and parse such syntax elements, and accordingly decode the associated video data. In some examples, encoder 20 can entropy-encode syntax elements into an encoded video stream. In such instances, decoder 30 can parse such syntax elements and accordingly decode the associated video data.

[0166] It should be noted that the encoding and decoding method described in the embodiments of this application is mainly used for the encoding and decoding process of video or images. This process exists in both the encoder 20 and the decoder 30. The encoder 20 and decoder 30 in the embodiments of this application can be, for example, the encoder / decoder corresponding to video standard protocols such as H.263, H.264, HEVV, MPEG-2, MPEG-4, VP8, VP9, ​​or next-generation video standard protocols (such as H.266).

[0167] Referring to Figure 2, which is a schematic / conceptual block diagram of an exemplary example of encoder 20, encoder 20 includes a residual calculation unit 204, a transform processing unit 206, a quantization unit 208, an inverse quantization unit 210, an inverse transform processing unit 212, a reconstruction unit 214, a buffer 216, a loop filter unit 220, a decoded picture buffer (DPB) 230, a prediction processing unit 260, and an entropy coding unit 270. Prediction processing unit 260 may include inter-frame prediction unit 244, intra-frame prediction unit 254, and mode selection unit 262. Inter-frame prediction unit 244 may include a motion estimation unit and a motion compensation unit (not shown). Encoder 20 shown in Figure 2 may also be referred to as a hybrid video encoder or a video encoder based on a hybrid video codec.

[0168] Referring to Figure 3, which is a schematic / conceptual block diagram of an example of a decoder 30, the decoder 30 is used to receive, for example, encoded image data (e.g., encoded bitstream) 21 encoded by encoder 20 to obtain a decoded image 331. During the decoding process, the decoder 30 receives video data from encoder 20, such as encoded video bitstreams representing image blocks of encoded video stripes and associated syntax elements.

[0169] In the example of Figure 3, decoder 30 includes an entropy decoding unit 304, an inverse quantization unit 310, an inverse transform processing unit 312, a reconstruction unit 314 (e.g., a summer 314), a buffer 316, a loop filter 320, a decoded image buffer 330, and a prediction processing unit 360. Prediction processing unit 360 may include an inter-frame prediction unit 344, an intra-frame prediction unit 354, and a mode selection unit 362. In some instances, decoder 30 may perform a decoding process that is generally the inverse of the encoding process described in video encoder 20 of Figure 2.

[0170] Referring to Figure 4, Figure 4 is a structural schematic diagram of a video decoding device 400 (e.g., a video encoding device 400 or a video decoding device 400) provided in an embodiment of this application. The video decoding device 400 is adapted to implement the embodiments described herein. In one embodiment, the video decoding device 400 may be a video decoder (e.g., decoder 30 of Figure 1A) or a video encoder (e.g., encoder 20 of Figure 1A). In another embodiment, the video decoding device 400 may be one or more components of the decoder 30 of Figure 1A or the encoder 20 of Figure 1A.

[0171] The video decoding device 400 includes: an input port 410 and a receiving unit (Rx) 420 for receiving data; a processor, logic unit, or central processing unit (CPU) 430 for processing data; a transmitter unit (Tx) 440 and an output port 450 for transmitting data; and a memory 460 for storing data. The video decoding device 400 may also include photoelectric conversion components and electro-optical (EO) components coupled to the input port 410, receiver unit 420, transmitter unit 440, and output port 450 for the input or output of optical or electrical signals.

[0172] Processor 430 is implemented in both hardware and software. Processor 430 can be implemented as one or more CPU chips, cores (e.g., multi-core processors), FPGAs, ASICs, and DSPs. Processor 430 communicates with ingress port 410, receiver unit 420, transmitter unit 440, egress port 450, and memory 460. Processor 430 includes either an encoding module 470 or a decoding module 470. The encoding / decoding module 470 implements the embodiments disclosed herein to implement the encoding or decoding methods provided in the embodiments of this application. For example, the encoding / decoding module 470 implements, processes, or provides various encoding operations. Therefore, the encoding / decoding module 470 provides a substantial improvement to the functionality of the video decoding device 400 and affects the transitions of the video decoding device 400 to different states. Alternatively, the encoding / decoding module 470 can be implemented with instructions stored in memory 460 and executed by processor 430.

[0173] Memory 460 includes one or more disks, tape drives, and solid-state drives, which can be used as overflow data storage devices to store programs while they are selectively executed, and to store instructions and data read during program execution. Memory 460 can be volatile and / or non-volatile, and can be read-only memory (ROM), random access memory (RAM), ternary content-addressable memory (TCAM), and / or static random access memory (SRAM).

[0174] Referring to FIG5, FIG5 is a simplified block diagram of an apparatus 500 that can be used as either or both of the source device 12 and destination device 14 in FIG1A according to an exemplary embodiment. The apparatus 500 can implement the technology of this application. In other words, FIG5 is a schematic block diagram of an implementation of an encoding or decoding apparatus (hereinafter referred to as decoding apparatus 500) according to an embodiment of this application. The decoding apparatus 500 may include a processor 510, a memory 530, and a bus system 550. The processor and the memory are connected via the bus system. The memory is used to store instructions, and the processor is used to execute the instructions stored in the memory. The memory of the decoding apparatus stores program code, and the processor can call the program code stored in the memory to execute various video encoding or decoding methods described in this application. To avoid repetition, detailed descriptions are not provided here.

[0175] In this embodiment, the processor 510 may be a central processing unit (CPU), or it may be other general-purpose processors, DSPs, ASICs, FPGAs, or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor may be a microprocessor or any conventional processor.

[0176] The memory 530 may include a read-only memory (ROM) device or a random access memory (RAM) device. Any other suitable type of storage device may also be used as memory 530. Memory 530 may include code and data 531 accessed by processor 510 using bus 550. Memory 530 may further include an operating system 533 and an application program 535, which includes at least one program that allows processor 510 to execute the encoding or decoding methods described in this application. For example, application program 535 may include applications 1 to N, which further include video encoding or decoding applications that execute the encoding or decoding methods described in this application.

[0177] In addition to the data bus, the bus system 550 may also include a power bus, a control bus, and a status signal bus. However, for clarity, all buses are labeled as bus system 550 in the diagram.

[0178] Optionally, the decoding device 500 may also include one or more output devices, such as a display 570. In one example, the display 570 may be a haptic display that combines a display with a haptic unit capable of operatively sensing touch input. The display 570 may be connected to the processor 510 via a bus 550.

[0179] For example, commonly used transform methods in image coding include discrete cosine transform and wavelet transform. Wavelet transform is a local transform method that can perform localized, multi-scale analysis of images, focusing on the details of signal changes, making it very suitable for image coding tasks.

[0180] Referring to Figure 6, which is an exemplary schematic / conceptual block diagram of a wavelet transform-based encoder, the encoder 60 includes, but is not limited to, a wavelet forward transform unit 610, a quantization unit 620, and an entropy coding unit 630. Specifically, the encoder acquires the original image 601 through an interface unit (also called an input interface, not shown in the figure). The original image 601 is input to the wavelet forward transform unit 610, and after wavelet transform (also called wavelet forward transform), wavelet transform coefficients 602 are obtained, which can also be simply referred to as wavelet coefficients in this embodiment. The quantization unit 620 quantizes the wavelet transform coefficients 602 to obtain quantization coefficients 603. The entropy coding unit 630 entropy codes the quantization coefficients 603 to obtain the image bitstream 604 of the original image, which can also be called a compressed bitstream or bitstream.

[0181] It should be noted that the wavelet transform-based encoder architecture in Figure 6 is for illustrative purposes only, and other instances may include more units or modules. For example, it may include, but is not limited to, prediction units, transform units, etc., and this application does not impose any limitations.

[0182] Referring to Figure 7, which is an exemplary schematic / conceptual block diagram of a wavelet transform-based decoder, the decoder 70 in the example of Figure 7 includes, but is not limited to, an entropy decoding unit 710, an inverse quantization unit 720, and an inverse wavelet transform unit 730. Specifically, at the decoding end, the decoder interfaces with the image bitstream 701 through an input interface (also called an interface unit, not shown in the figure). The entropy decoding unit 710 performs entropy decoding on the image bitstream 701 to obtain quantization coefficients 702. The image bitstream 701 can be a bitstream 604 generated based on the encoder 60 in Figure 6. The inverse quantization unit 720 performs inverse quantization on the quantization coefficients 702 to obtain inverse quantization coefficients 703 (dequantized coefficient(s)), which can also be called reconstructed coefficients, reconstructed wavelet coefficients, etc. The inverse wavelet transform unit 730 performs inverse wavelet transform on the inverse quantization coefficients 703 to obtain the reconstructed image 704.

[0183] It should be noted that the wavelet transform-based decoder architecture in Figure 7 is for illustrative purposes only, and other instances may include more units or modules. For example, it may include, but is not limited to, prediction units, inverse transform units, etc., and this application does not impose any limitations.

[0184] For example, the wavelet coefficients obtained after wavelet transform include wavelet coefficients of the high-frequency subband and wavelet coefficients of the low-frequency subband. In the architecture shown in Figures 6 and 7, the codec performs the same processing on the wavelet coefficients of the high-frequency subband and the low-frequency subband, which has high processing complexity. In the embodiments of this application, the wavelet coefficients of the high-frequency subband can be simply referred to as the high-frequency subband, and the wavelet coefficients of the low-frequency subband can be simply referred to as the low-frequency subband. It can be understood that the high-frequency subband obtained after wavelet transform can optionally be the set of wavelet coefficients of the high-frequency subband, and the low-frequency subband obtained after wavelet transform can optionally be the set of wavelet coefficients of the low-frequency subband.

[0185] For example, the frequency of the high-frequency sub-band is greater than the frequency of the low-frequency sub-band. This can be understood as the frequency of various coefficients corresponding to the high-frequency sub-band in this application (such as wavelet coefficients, reconstruction coefficients, inverse quantization coefficients, etc. involved in this application) being greater than the frequency of the coefficients of the low-frequency sub-band.

[0186] This application provides a wavelet transform-based codec that can independently encode and decode low-frequency and high-frequency sub-bands, effectively reducing encoding and decoding complexity and improving efficiency. For example, an image undergoes wavelet transform to obtain low-frequency and high-frequency sub-bands, which are then encoded to generate low-frequency and high-frequency sub-band bitstreams, respectively. The low-frequency sub-band can be understood as a sub-image representing the low-frequency signal (or low-frequency information) of the original image, and the high-frequency sub-band can be understood as a sub-image representing the high-frequency signal (or high-frequency information) of the original image.

[0187] Referring to Figure 8, which is a schematic / conceptual block diagram of an encoder as an example, the encoder 80 includes, but is not limited to, a sub-graph partitioning unit 810, a wavelet forward transform unit 820, a low-frequency sub-band processing path 830, and a high-frequency sub-band processing path 840. Optionally, the wavelet forward transform unit and the wavelet inverse transform unit in this embodiment can also be collectively referred to as wavelet transform units, which can be understood as performing both wavelet forward transform processing and wavelet inverse transform processing. In this application, the low-frequency sub-band processing path can also be referred to as a low-frequency sub-band processing unit, and the high-frequency sub-band processing path can also be referred to as a high-frequency sub-band processing unit.

[0188] The low-frequency subband processing path 830 includes, but is not limited to: a transform / quantization unit 831 (also known as a low-frequency subband transform / quantization unit) and a low-frequency subband entropy coding unit 832.

[0189] The high-frequency subband processing path 840 includes, but is not limited to: a transform / quantization unit 841 (also known as a high-frequency subband transform / quantization unit) and a high-frequency subband entropy coding unit 842.

[0190] Specifically, encoder 80 receives image 801. Image 801 can be an image in an image sequence that forms a video or video sequence. Image 801 can be referred to as the current image or the image to be encoded, and image 801 can be the original image or an image obtained by processing the original image.

[0191] The sub-image partitioning unit 810 is used to acquire the current image and partition it to obtain at least one sub-image. Specifically, the sub-image partitioning unit 810 partitions the current image into N sub-images according to a sub-image partitioning method, where N is an integer greater than 0 (or an integer greater than 1). The sub-image partitioning method can include, but is not limited to, at least one of the following:

[0192] The width and / or height of the subgraph are multiples of 128;

[0193] The maximum width of the subimage is 1024 pixels;

[0194] The minimum height and / or width of the subimage is 256 pixels;

[0195] The original image resolution is less than or equal to 1080p, and N is an integer greater than 1 and less than or equal to 8; or,

[0196] The original image has a length greater than or equal to 4320 pixels, a width greater than or equal to 2160 pixels, and N is an integer greater than 1 and less than or equal to 16; or,

[0197] The original image has a length greater than or equal to 7680 pixels, a width greater than or equal to 4320 pixels, and N is an integer greater than 1 and less than or equal to 32.

[0198] For example, common video resolutions include: 1280x720, 1280x1080, 1440x1080, 1920x1080 (1080p), 2048x1080, 2048x1556, 3840x2160 (4K), 4096x2160, 5120x2700, 6144x3240, 7680x4320 (8K), and 8192x4320. The above values ​​are only illustrative examples and can be set according to actual needs.

[0199] For example, the subgraph partitioning unit 810 can set specific subgraph specifications (including width and height) based on the above subgraph partitioning method. The specific values ​​can be set according to actual needs within the range specified by the subgraph partitioning method.

[0200] Referring to Figure 9A, which is an exemplary schematic diagram of sub-image partitioning, in the example of Figure 9A, the sub-image partitioning unit 810 can partition the image 801 into m*n sub-images according to the sub-image partitioning method. Optionally, in this example, the width and height of each sub-image satisfy a multiple of 128.

[0201] Referring to Figure 9B, which is an exemplary schematic diagram of sub-image partitioning, in the example of Figure 9B, the sub-image partitioning unit 810 can partition the image into m*n sub-images according to the sub-image partitioning method. When the sub-image partitioning unit 810 partitions the boundary portion of the current image, the width and / or height of the boundary sub-images may optionally not satisfy a multiple of 128. Figure 9B only illustrates this by showing that the width of some boundaries does not satisfy a multiple of 128. Referring to Figure 9B, in this embodiment, for sub-images whose width and height do not satisfy a multiple of 128, the sub-image partitioning unit 810 can pad these sub-images, such as the gray portion in Figure 9B. Taking sub-image 1_n as an example, the height of sub-image 1_n satisfies a multiple of 128, but its width does not. The sub-image partitioning unit 810 pads sub-image 1_n.

[0202] In one possible implementation, the width and / or height of the filled subgraph can optionally be less than or equal to the subgraph size set by the subgraph partitioning method. For example, the size (i.e., width and height) of the filled subgraph 1_n can be the same as that of subgraph 1_1. As another example, the size of the filled subgraph 1_n can be less than the size of subgraph 1_1, where the width of subgraph 1_1 is a, the height is b, the width of subgraph 1_n before filling is c, the height is b, c is less than b, and c is not a multiple of 128. The subgraph partitioning unit 810 fills the subgraph 1_n, and the width of the filled subgraph 1_n is d, and the height is b. Here, d can optionally be a multiple of 16, and d is greater than c and less than or equal to a.

[0203] In this way, by padding the sub-images, each macroblock can meet the 8x8 (pixel) partitioning requirement during the block division process of the encoding. Furthermore, by finding the least common multiple of the width and / or height of the sub-image before padding and 16, sub-images that do not meet the multiple of 16 are padded. This ensures that the size of the sub-image is a multiple of 16 while minimizing the size of the padded sub-image, thereby reducing the encoding complexity of the padded sub-image.

[0204] Optionally, the sub-image partitioning method can be the same for each image in the same video sequence.

[0205] Optionally, the sub-image division unit 810 can divide the image into sub-images along the horizontal and vertical directions, starting from the upper left corner, according to a preset sub-image size. The division order can be set according to actual needs. Typically, the sub-images that need to be filled are boundary sub-images, as shown in Figure 9B.

[0206] In this embodiment, each sub-image is encoded and decoded independently. Specifically, the image is divided into N sub-images, and the encoder 80 encodes each of the N sub-images separately. During the encoding process, a sub-image can also be referred to as the current sub-image or the sub-image to be encoded.

[0207] Referring again to Figure 8, the wavelet forward transform unit 820 is used to perform wavelet transform (also called wavelet forward transform) on the subgraph to obtain low-frequency subband and high-frequency subband. The low-frequency subband includes low-frequency signals in the subgraph that satisfy the low-frequency filter coefficients, and the high-frequency subband includes high-frequency signals in the subgraph that have been decomposed by the high-frequency filter in the wavelet transform.

[0208] Referring to Figure 10, which is an exemplary schematic diagram of wavelet transform, in the example of Figure 10, the wavelet forward transform unit 820 acquires the current sub-image, for example, sub-image 1_1. The wavelet forward transform unit 820 performs a wavelet transform on the current sub-image, wherein the wavelet transform includes one horizontal wavelet transform and one vertical wavelet transform to obtain the wavelet coefficients of the low-low (LL) sub-band (abbreviated as LL sub-band), the wavelet coefficients of the low-high (LH) sub-band (abbreviated as LH sub-band), the wavelet coefficients of the high-high (HH) sub-band (abbreviated as HH sub-band), and the wavelet coefficients of the high-low (HL) sub-band (abbreviated as HL sub-band).

[0209] In this embodiment, the low-frequency subband includes an LL subband, and the high-frequency subband includes an LH subband, an HH subband, and an HL subband. Optionally, the LL subband, LH subband, HH subband, and HL subband have the same dimensions (including width and height).

[0210] Referring again to Figure 8, the low-frequency subband processing path 830 is used to encode the low-frequency subband to obtain low-frequency subband encoded data 806, which can also be referred to as coded low-frequency subband. The high-frequency subband processing path 840 is used to encode the high-frequency subband to obtain high-frequency subband encoded data 809, which can also be referred to as coded high-frequency subband. In this application, the high-frequency subband encoded data can also be referred to as second encoded data.

[0211] Specifically, the wavelet forward transform unit 820 outputs wavelet coefficients 803 of the low-frequency subband to the transform / quantization unit 831, and outputs wavelet coefficients 804 of the high-frequency subband to the transform / quantization unit 841.

[0212] For example, the transform / quantization unit 831 is used to obtain the wavelet coefficients 803 of the low-frequency sub-band, perform quantization processing on the wavelet coefficients 803 of the low-frequency sub-band, or perform transform and quantization processing, and output the quantized coefficients 805 of the low-frequency sub-band, or the quantized wavelet coefficients of the low-frequency sub-band.

[0213] The transform / quantization unit 831 outputs the quantization coefficients 805 of the low-frequency subband to the low-frequency subband entropy encoding unit 832. Optionally, the transform / quantization unit 831 may include, but is not limited to, a transform processing unit and a quantization processing unit (not shown in the figure).

[0214] The transform processing unit is used to transform the low-frequency subband and output transform coefficients, also known as low-frequency subband transform coefficients. The quantization processing unit is used to quantize the subband or the transformed transform coefficients and output quantized coefficients (also known as quantization results).

[0215] The low-frequency subband entropy coding unit 832 is used to acquire the data to be encoded and perform entropy coding on the data to be encoded to obtain low-frequency subband encoded data. The data to be encoded may include, but is not limited to, the quantization coefficients 805 of the low-frequency subband. In some instances, the data to be encoded may also include parameters or information (or syntax elements) input from other modules not shown in the figure. The low-frequency subband encoded data may also be referred to as the first encoded data in this application.

[0216] Referring again to Figure 8, the transform / quantization unit 841 is used to quantize the wavelet coefficients 804 of the high-frequency subband, or to perform both transform and quantization processing, to obtain the quantized coefficients 807 of the high-frequency subband, which can also be referred to as the quantized wavelet coefficients of the high-frequency subband. The transform / quantization unit 841 outputs the quantized coefficients 807 of the high-frequency subband to the high-frequency subband entropy coding unit 842. For parts not described, please refer to the low-frequency subband transform / quantization unit 831; further details are omitted here.

[0217] The high-frequency subband entropy coding unit 842 is used to acquire the data to be encoded and perform entropy coding on the data to be encoded to obtain high-frequency subband encoded data 808, which can also be called encoded high-frequency subband. Optionally, the data to be encoded may include, but is not limited to, the quantization coefficients 807 of the high-frequency subband. In some instances, the data to be encoded may also include parameters or information (or syntax elements) input from other modules not shown in the figure.

[0218] Optionally, the entropy coding unit (including the low-frequency subband entropy coding unit 832 and the high-frequency subband entropy coding unit 842) is used to encode the data to be encoded using an entropy coding algorithm or scheme. The aforementioned entropy coding scheme may be, for example, at least one of the following: variable-length coding (VLC), context-adaptive VLC (CAVLC), arithmetic coding, and context-adaptive binary arithmetic coding (CABAC).

[0219] Optionally, the encoder 80 may also include, but is not limited to, a combining unit (not shown in the figure), which may also be called a multiplexer (MUX). The combining unit is used to generate an image bitstream based on the low-frequency subband coded data 806 and the high-frequency subband coded data 808.

[0220] Specifically, the combining unit writes low-frequency subband coded data 806 into the image bitstream and writes high-frequency subband coded data 808 into the image bitstream. In this embodiment, by encoding the low-frequency subband and high-frequency subband separately, the low-frequency subband coded data and high-frequency subband coded data can be decoded independently. That is, at the decoding end, it can independently decode the low-frequency subband coded data and high-frequency subband coded data in the image bitstream, thereby improving decoding efficiency.

[0221] As mentioned above, a single image can be divided into multiple sub-images, for example, N sub-images. Each sub-image can be decomposed into wavelet coefficients of a high-frequency sub-band and wavelet coefficients of a low-frequency sub-band after wavelet forward transform. Encoder 80 independently encodes the low-frequency and high-frequency sub-bands of each sub-image to obtain the low-frequency sub-band encoded data and high-frequency sub-band encoded data of a single sub-image. In this way, the combining unit can obtain the high-frequency sub-band encoded data and low-frequency sub-band encoded data of each of the N sub-images, that is, obtain N high-frequency sub-band encoded data (optionally, the high-frequency sub-band encoded data of each sub-image includes the HL sub-band encoded data corresponding to the HL sub-band, the HH sub-band encoded data corresponding to the HH sub-band, and the LH sub-band encoded data corresponding to the LH sub-band) and N low-frequency sub-band encoded data. The combining unit can optionally write the low-frequency sub-band encoded data and high-frequency sub-band encoded data of the N sub-images into the image bitstream. The format (or structure) of the image bitstream will be described in detail below.

[0222] Referring to Figure 11, which is a schematic / conceptual block diagram of an exemplary decoder, decoder 110 is used to receive, for example, a bitstream encoded by an encoder to obtain a decoded image, also referred to as a reconstructed image 1108. During the decoding process, the decoder receives a bitstream (also referred to as the bitstream of the original image, or the image data of the original image) from the encoder.

[0223] In the example shown in Figure 11, the decoder 110 includes, but is not limited to: a high-frequency subband processing path 1120, a low-frequency subband processing path 1110, a wavelet inverse transform unit 1130, and a subgraph stitching unit 1140.

[0224] The low-frequency subband processing path 1110 includes, but is not limited to: a low-frequency subband entropy decoding unit 1111 and an inverse quantization / inverse transform unit 1112 (also referred to as a low-frequency subband inverse quantization / inverse transform unit). The high-frequency subband decoding path 1120 includes, but is not limited to: a high-frequency subband entropy decoding unit 1121 and an inverse quantization / inverse transform unit 1122 (also referred to as a high-frequency subband inverse quantization / inverse transform unit).

[0225] For example, decoder 110 receives an image bitstream and obtains a reconstructed image 1108 (also known as a decoded image) based on high-frequency subband coded data 1102 and low-frequency subband coded data 1101 in the image bitstream.

[0226] For example, the low-frequency subband entropy decoding unit 1111 is used to acquire low-frequency subband encoded data 1101 in the image bitstream to obtain entropy decoding data, which includes, but is not limited to, the quantization coefficients 1103 of the low-frequency subband. Specifically, the low-frequency subband entropy decoding unit 1111 performs entropy decoding processing on the low-frequency subband encoded data 1101 to obtain entropy decoding data. The low-frequency subband entropy decoding unit 1111 outputs the quantization coefficients 1103 of the low-frequency subband to the inverse quantization / inverse transform unit 1112.

[0227] The inverse quantization / inverse transform unit 1112 is used to obtain the quantization coefficients 1103 of the low-frequency subband to obtain the reconstruction coefficients 1105 of the low-frequency subband, which can also be simply referred to as the reconstructed low-frequency subband. In some instances, it can also be called the reconstructed value of the low-frequency subband, the reconstruction coefficient of the low-frequency subband, or the reconstructed wavelet coefficients of the low-frequency subband. Specifically, the low-frequency inverse quantization / inverse transform unit performs inverse quantization and / or inverse transform processing on the quantization coefficients to obtain the reconstructed low-frequency subband, such as the reconstructed LL subband. Optionally, the inverse quantization / inverse transform unit 1112 may include, but is not limited to, an inverse quantization processing unit and an inverse transform processing unit (not shown in the figure). The inverse quantization processing unit can be used to perform inverse quantization processing on the input parameters to obtain inverse quantization coefficients. The inverse transform unit can be used to perform inverse transform processing on the input parameters to obtain inverse transform coefficients, which can also be called inverse transform coefficients. For example, the inverse transform processing unit can perform inverse transform processing on the inverse quantization coefficients output by the inverse quantization processing unit to obtain inverse transform inverse quantization coefficients.

[0228] The high-frequency subband entropy decoding unit 1121 is used to acquire the high-frequency subband encoded data 1102 in the image bitstream to obtain entropy-decoded data. The entropy-decoded data includes, but is not limited to, the quantization coefficients 1104 of the high-frequency subband. Specifically, the high-frequency subband entropy decoding unit 1121 performs entropy decoding processing on the high-frequency subband encoded data 1102 to obtain the entropy-decoded data. The high-frequency subband entropy decoding unit 1121 outputs the quantization coefficients 1104 of the high-frequency subband to the inverse quantization / inverse transform unit 1122.

[0229] The inverse quantization / inverse transform unit 1122 is used to obtain the quantization coefficients 1104 of the high-frequency subband, resulting in the reconstructed coefficients 1106 of the high-frequency subband, which can be simply referred to as the reconstructed high-frequency subband. In some instances, it can also be called the reconstructed value of the high-frequency subband, the reconstructed wavelet coefficients of the high-frequency subband, etc. The inverse quantization / inverse transform unit 1122 outputs the reconstructed high-frequency subband to the wavelet inverse transform unit 1130. Specifically, the inverse quantization / inverse transform unit 1122 performs inverse quantization processing on the quantization coefficients 1104 of the high-frequency subband, or performs inverse quantization and inverse transform processing, to obtain the reconstructed high-frequency subband. For example, this includes reconstructing the HH subband (e.g., the reconstructed coefficients of the HH subband), reconstructing the HL subband (e.g., the reconstructed coefficients of the HL subband), and reconstructing the LH subband (e.g., the reconstructed coefficients of the LH subband).

[0230] For example, the wavelet inverse transform unit 1130 is used to obtain the reconstruction coefficients 1105 of the low-frequency sub-band and the reconstruction coefficients 1106 of the high-frequency sub-band to obtain the reconstructed sub-map 1107. Specifically, the wavelet inverse transform unit 1130 can obtain the reconstructed low-frequency sub-band and the reconstructed high-frequency sub-band of each sub-map. The wavelet inverse transform unit performs wavelet inverse transform processing on the obtained reconstructed low-frequency sub-band and reconstructed high-frequency sub-band corresponding to the same sub-map to obtain the reconstructed sub-map. Its inverse transform process is the inverse of the wavelet forward transform process, which will not be described in detail here.

[0231] The sub-image stitching unit 1140, also known as an image reconstruction unit or sub-image combination unit, is used to obtain reconstructed sub-images of the original image to obtain a reconstructed image of the original image. Specifically, the sub-image stitching unit 1140 obtains N reconstructed sub-images corresponding to the current decoded image. Based on the N reconstructed sub-images, the sub-image stitching unit 1140 can obtain the reconstructed image (also known as the decoded image or the decoded image) of the current image.

[0232] Based on the codecs shown in Figures 8 and 11, there can be more variations of the codec, such as including more processing units or modules.

[0233] Referring to Figure 12, which is a schematic / conceptual block diagram of an encoder as an example, the encoder in the example of Figure 12 includes, but is not limited to, a sub-graph partitioning unit 1210, a wavelet forward transform unit 1220, a low-frequency sub-band processing path 1230, and a high-frequency sub-band processing path 1240.

[0234] The descriptions of the subgraph partitioning unit 1210 and the wavelet forward transform unit 1220 can be found in the relevant content in Figure 8, and will not be repeated here.

[0235] The low-frequency subband processing path 1230 is used to obtain the wavelet coefficients 1203 of the low-frequency subband to obtain the low-frequency subband encoded data 1213. The low-frequency subband processing path 1230 includes, but is not limited to: a block partitioning unit 1231 (also called the low-frequency subband block partitioning unit 1231 or the first block partitioning unit 1231), a residual calculation unit 1232, a prediction unit 1237, a control unit 1238, a transform / quantization unit (also called the low-frequency subband transform / quantization unit 1233 or the first transform / quantization unit), an inverse quantization / inverse transform unit 1234 (also called the low-frequency subband inverse quantization / inverse transform unit 1234 or the first inverse transform / inverse quantization unit), a low-frequency subband wavelet coefficient 1203 splicing unit 1246, a low-frequency subband wavelet coefficient 1203 splicing unit 1246, and a low-frequency subband entropy coding unit 1239, etc.

[0236] The high-frequency subband processing path 1240 is used to acquire high-frequency subbands to obtain high-frequency subband encoded data. The high-frequency subband processing path 1240 includes, but is not limited to: block partitioning unit 1231 (also referred to as high-frequency subband block partitioning unit 1231 or second block partitioning unit 1231), transform / quantization unit (also referred to as transform / quantization unit 1242 or second transform / quantization unit), high-frequency subband entropy coding unit 1243, etc.

[0237] Alternatively, in some instances, the encoder may include more or fewer units or modules than in the structure shown in Figure 12.

[0238] The image 1201 encoding method provided in this application will be described in detail below with reference to the encoder shown in Figure 12:

[0239] The codec receives image 1201. A description of image 1201 can be found above and will not be repeated here.

[0240] Sub-image partitioning unit 1210 partitions image 1201 into sub-images and outputs N sub-images. N is an integer greater than 0. In this embodiment, each sub-image is encoded and decoded independently. During the encoding process, sub-image 1202 can be referred to as the current sub-image or the sub-image to be encoded.

[0241] Wavelet forward transform unit 1220 performs wavelet forward transform on the current sub-image to obtain wavelet coefficients 1203 (hereinafter referred to as low-frequency sub-band) and wavelet coefficients 1214 (hereinafter referred to as high-frequency sub-band) of the current sub-image. The wavelet coefficients 1203 of the low-frequency sub-band include the wavelet coefficients of the LL sub-band, and the high-frequency sub-band includes the wavelet coefficients of the LH, HL, and HH sub-bands. In this embodiment, each sub-image of the image can be independently encoded and decoded, and the high-frequency sub-band and low-frequency sub-band of each sub-image are independently encoded and decoded. The LH, HL, and HH sub-bands in the high-frequency sub-band can also be independently encoded and decoded.

[0242] The block partitioning unit 1231 (which may be called the low-frequency sub-band block partitioning unit) is used to obtain the wavelet coefficients 1203 of the low-frequency sub-band of the current sub-graph 1202, so as to obtain at least one macroblock 1204 of the low-frequency sub-band of the sub-graph 1202, wherein the macroblock can also be understood as a set of partial coefficients in the wavelet coefficients of the low-frequency sub-band.

[0243] Specifically, the block partitioning unit 1231 partitions the wavelet coefficients 1203 of the low-frequency sub-band of the current subgraph 1202 into blocks based on the block partitioning method, obtaining at least one macroblock 1204 of the low-frequency sub-band of the current subgraph, for example, M macroblocks, where M is an integer greater than 0 (or greater than 1). The low-frequency block partitioning unit 1231 outputs the macroblocks 1204 of the wavelet coefficients 1203 of the current low-frequency sub-band one by one to the residual calculation unit 1232 and the control unit 1238.

[0244] In this embodiment, macroblock 1204 is a basic encoding / decoding unit. During the encoding process, macroblock 1204 can also be referred to as the current block, current image 1201 block, macroblock 1204 to be encoded, block to be encoded, image 1204 block to be encoded, etc.

[0245] Alternatively, the block partitioning method includes, but is not limited to:

[0246] The wavelet coefficients 1203 of both the high-frequency subband and the low-frequency subband are divided into basic coding units of 8x8 macroblocks 1204 (unit is pixels).

[0247] For example, as described above, each subband uses macroblock 1204 as the basic coding unit. The macroblock 1204 currently to be encoded is referred to as the current macroblock 1204. Specifically, the low-frequency subband processing path 1230 encodes each macroblock 1204 of the wavelet coefficients 1203 of the low-frequency subband block by block. For example, encoding and prediction are performed on each macroblock 1204. The following description only uses the encoding process of the current macroblock 1204; the processing processes for other macroblocks are the same, and will not be described in detail here. For example, in encoding, it refers to the macroblock currently being encoded; in decoding, it refers to the macroblock currently being decoded. The decoded macroblock in the reference image used for predicting the current macroblock 1204 is called the reference block (i.e., the low-frequency subband reconstruction block 1209 in the figure). The reference block is the block that provides the reference signal for the current block, where the reference signal represents the pixel value within the macroblock 1204. The block in the reference image that provides the prediction signal for the current block can be called prediction block 1205, where the prediction signal represents the pixel value, sample value, or sample signal within prediction block 1205. For example, after traversing multiple reference blocks, an optimal reference block is found, which will provide the prediction for the current block; this block is called prediction block 1205.

[0248] Specifically, referring to Figure 12, the residual calculation unit 1232 is used to obtain the current macroblock 1204 and the prediction block 1205 (further details of the prediction block 1205 are provided below) to obtain the residual block 1206. Specifically, the residual calculation unit performs residual calculations on the current macroblock 1204 and the prediction block 1205 to obtain the residual block 1206. The residual calculation unit 1232 outputs the residual block 1206 to the transform / quantization unit 1233.

[0249] The transform / quantization unit 1233 is used to acquire the residual block 1206 to obtain the residual coefficients 1207. Specifically, the transform / quantization unit 1233 performs transform and / or quantization processing on the residual block 1206 to obtain the residual coefficients 1207, which can also be called the quantization coefficients of the residual block, or the quantized residual block. The transform / quantization unit 1233 outputs the residual coefficients 1207 to the inverse quantization single / inverse transform unit 1234 and the low-frequency subband entropy coding unit 1239.

[0250] The inverse quantization / inverse transform unit 1234, also known as the inverse quantization / inverse transform unit, is used to obtain the residual coefficients 1207 to obtain the residual reconstruction block 1208. Specifically, the inverse quantization / inverse transform unit 1234 performs inverse quantization and / or inverse transform processing on the residual coefficients 1207 to obtain the residual reconstruction block 1208, which can also be referred to as the inverse quantization coefficients of the residual block, the inverse quantized residual block, etc. The inverse quantization / inverse transform unit 1234 outputs the residual reconstruction block 1208 to the low-frequency subband splicing unit 1236.

[0251] The dequantization / inverse transform unit 1234 may include a dequantization unit and an inverse transform unit (not shown in the figure). The dequantization unit is used to dequantize the input coefficients, and the inverse transform unit is used to inverse transform the input coefficients.

[0252] The low-frequency subband reconstruction unit 1235 is used to obtain a low-frequency subband reconstruction block 1209 based on the prediction block 1205 and the residual reconstruction block 1208. Specifically, the low-frequency subband reconstruction unit 1235 adds the residual reconstruction block 1208 to the prediction block 1205 to obtain the low-frequency subband reconstruction block 1209, which can also be referred to as the reconstructed low-frequency subband macroblock. Optionally, the low-frequency subband reconstruction unit 1235 outputs the low-frequency subband reconstruction block 1209 to the prediction unit 1237 and the low-frequency subband splicing unit 1236. Optionally, the low-frequency subband reconstruction unit 1235 outputs the low-frequency subband reconstruction block 1209 to the control unit 1238.

[0253] The low-frequency subband stitching unit 1236 is used to obtain the reconstructed low-frequency subband 1211, which can also be referred to as the reconstructed value or reconstructed data of the low-frequency subband, based on the low-frequency subband reconstruction block 1209. Optionally, the low-frequency subband stitching unit 1236 outputs the reconstructed low-frequency subband 1211 to the prediction unit 1237. Optionally, the low-frequency subband stitching unit 1236 outputs the reconstructed low-frequency subband 1211 to the control unit 1238.

[0254] Specifically, as described above, the low-frequency subband uses macroblocks as the basic coding unit, and the low-frequency subband splicing unit 1236 can obtain M low-frequency subband reconstruction blocks of a low-frequency subband. The low-frequency subband splicing unit 1236 can reconstruct the corresponding low-frequency subband based on the M low-frequency subband reconstruction blocks, that is, obtain the reconstructed low-frequency subband 1211.

[0255] The control unit 1238, also known as the mode selection unit, is used to determine the syntax element 1213 based on the macroblock 1204 (i.e. the current block); or to determine the syntax element 1213 based on the current macroblock 1204, the low-frequency subband reconstruction block 1209, and the reconstructed low-frequency subband 1211.

[0256] Syntax element 1213 includes at least one syntax element, such as pattern information. Pattern information, also known as prediction mode information, is used to indicate the prediction mode (or prediction method) of prediction unit 1237, such as inter-frame or intra-frame prediction mode. Control unit 1238 can output syntax element 1213 to prediction unit 1237 and low-frequency subband entropy coding unit 1239.

[0257] Prediction unit 1237, also known as prediction processing unit, is used to acquire syntax element 1213 and perform prediction processing based on syntax element 1213. Specifically, prediction unit 1237 may select a prediction mode based on syntax element 1213 (e.g., mode information in the syntax element). In one example, prediction unit 1237 may acquire low-frequency subband reconstruction block 1209 based on syntax element 1213 to acquire prediction block 1205. Specifically, prediction unit 1237 may perform intra-frame prediction based on low-frequency subband reconstruction block 1209 to acquire prediction block 1205. In another example, prediction unit 1237 may acquire reconstructed low-frequency subband 1211 based on syntax element 1213 to acquire prediction block 1205.

[0258] The prediction unit 1237 outputs prediction block 1205 to the residual calculation unit 1232 and the low-frequency sub-band splicing unit 1236.

[0259] The low-frequency subband entropy coding unit 1239 is used to obtain low-frequency subband encoded data 1213, also known as encoded low-frequency subband, based on residual coefficients 1207 and syntax elements 1213. Specifically, the low-frequency subband entropy coding unit 1239 uses an entropy coding algorithm or scheme (e.g., variable length coding (VLC) scheme, context adaptive VLC (CAVLC) scheme, arithmetic coding scheme, context adaptive binary arithmetic coding (CABAC), syntax-based context-adaptive binary arithmetic coding (SBAC), probability interval partitioning entropy (PIPE) coding, or other entropy coding methods or techniques) to entropy encode the residual coefficients 1207 and syntax elements 1213 to obtain low-frequency subband encoded data 1213 output in the form of, for example, an encoded bitstream.

[0260] Referring again to Figure 12, the block partitioning unit 1241, also known as the high-frequency subband block partitioning unit, is used to obtain the high-frequency subband of the current subgraph 1202 to obtain at least one macroblock 1215 of the high-frequency subband of the subgraph 1202. For a detailed description, please refer to the low-frequency subband section; it will not be repeated here. Specifically, the block partitioning unit 1241 partitions the high-frequency subband 1214 of the current subgraph 1202 (hereinafter referred to as the current high-frequency subband) into blocks based on the block partitioning method, obtaining at least one macroblock 1215 of the current subgraph 1202, for example, M macroblocks, where M is an integer greater than 0 (or an integer greater than 1). Other undescribed parts can be referred to the relevant description of the block partitioning unit 1231; it will not be repeated here.

[0261] Block partitioning unit 1241 outputs the macroblocks of the current high-frequency subband one by one to quantization / conversion unit 1242.

[0262] The transform / quantization unit 1242 is used to transform and / or quantize the macroblock 1215 to obtain the quantization coefficients 1216 of the high-frequency subband block (i.e., the quantization coefficients of the current macroblock). The transform / quantization unit 1242 outputs the quantization coefficients 1216 of the high-frequency subband block to the high-frequency subband entropy coding unit 1243.

[0263] The high-frequency subband entropy coding unit 1243 is used to perform entropy coding on the data to be encoded to obtain high-frequency subband encoded data 1217. The data to be encoded may include, but is not limited to, the quantization coefficients and syntax elements of each high-frequency subband block. The high-frequency subband encoded data 1217 includes, but is not limited to, HH subband encoded data, HL subband encoded data, and LH subband encoded data.

[0264] The encoding and decoding method provided in this application supports two scenarios: full I-frame configuration and I / P frame alternating encoding configuration. The encoder architecture shown in Figure 12 adds relevant modules required for the prediction process based on the wavelet transform architecture shown in Figure 8, which can improve the compression efficiency of I / P frame alternating encoding for scenarios such as fixed camera positions and slow camera movement.

[0265] Optionally, the encoder may also include a combination unit (not shown in the figure) for generating an image bitstream based on low-frequency subband coded data and high-frequency subband coded data. The specific process can be referred to the relevant description in Figure 8 above.

[0266] The bitstream output by the encoder in the embodiments of this application will be described in detail below. The bitstream structure described below can be applied to the encoders shown in Figures 8 and 12, and of course, it can also be applied to other encoder variations based on Figures 8 or 12.

[0267] For example, as described above, the low-frequency subband entropy coding unit 1239 and the high-frequency subband entropy coding unit 1243 output low-frequency subband coded data 1213 and high-frequency subband coded data 1217, respectively. This can be understood as the encoder 120 independently encoding the low-frequency and high-frequency subbands of each subgraph, outputting low-frequency and high-frequency subband coded data corresponding to the current subgraph.

[0268] Referring to Figure 13A, which is an exemplary schematic diagram of an image bitstream structure, the image bitstream in the example of Figure 13A includes, but is not limited to, image header information and image data (also referred to as an image data region).

[0269] For example, the image data includes at least one image data region (also referred to as an image data sub-region), such as, but not limited to, a first image data region and a second image data region. During the encoding process, the encoder (e.g., through a combination unit) writes high-frequency subband encoded data and low-frequency subband encoded data into the image bitstream. Specifically, the encoder writes high-frequency subband encoded data into the first image data region and low-frequency subband encoded data into the second image data region.

[0270] For example, image header information includes, but is not limited to, offset information and image size information.

[0271] For example, image size information is used to indicate the size of the original image. As mentioned above, during the encoding process, some sub-images may be padded during sub-image partitioning to ensure that the length and width of each sub-image are multiples of 16. Thus, during decoding, the size of the reconstructed image obtained by the decoder may be larger than the original image size. The decoder can process the reconstructed image based on the image size information to remove the padded portions.

[0272] For example, offset information is used to indicate the position of a data region in the image bitstream, and can also be understood as indicating the position of independently decodeable coded data in the image bitstream. When decoding coded data (i.e., the image bitstream) according to this application, the offset information in the image header information can be used to obtain independently decodeable coded data, and decoding operations can be performed on the coded data. The independently decodeable coded data (e.g., low-frequency subband coded data and high-frequency subband coded data) can be decoded synchronously during decoding to improve decoding efficiency.

[0273] In one example, the offset information can be the length of the image data region containing adjacent, independently decodeable encoded data in the image bitstream.

[0274] In another example, the offset information can be the offset (i.e., the difference) between the starting position of the image data region where the independently decoded encoded data is located and the ending position of the image header information.

[0275] Referring to Figure 13B, which is an exemplary schematic diagram of an image bitstream structure, the bitstream in the example of Figure 13B includes, but is not limited to, image header information and image data. The image header information includes, but is not limited to, offset information, etc., detailed concepts of which can be found above and will not be repeated here. The image data includes, but is not limited to, low-frequency subband coded data and high-frequency subband coded data. The low-frequency subband coded data is written to the first image data area, and the high-frequency subband coded data is written to the second image data area. Other descriptions can be found in Figure 13A and will not be repeated here.

[0276] It should be noted that the embodiments in this application only use the image bitstream of a single image as an example for illustration, that is, the bitstream includes only one image data. In the process of encoding video images, the encoder can generate an encoded image bitstream for each image, that is, the image bitstream includes multiple image data, and each image data carries the encoded data of the corresponding image.

[0277] Referring to Figure 14A, which is an exemplary schematic diagram of an image bitstream structure, in the example of Figure 14A, as described above, the high-frequency subband coding data of each sub-image further includes: HH subband coding data, HL subband coding data, and LH subband coding data. Accordingly, in this example, the image data includes, but is not limited to: HH subband coding data, HL subband coding data, and LH subband coding data of each sub-image of the image.

[0278] For example, in the example shown in Figure 14A, LL subband coded data is written to the second image data region, HL subband coded data is written to the first image data subregion, HH subband coded data is written to the second image data subregion, and LH subband coded data is written to the dotted image data subregion. The writing order of each high-frequency subband is only an illustrative example and will not be repeated below.

[0279] Optionally, in the example shown in Figure 14A, the offset information of each segment of independently decodeable encoded data in the image header information may include, but is not limited to: the offset of the starting position of the first image data sub-region relative to the ending position of the image header information (this data is usually measured in n bytes), the offset of the starting position of the second image data sub-region relative to the ending position of the image header information, and the offset of the starting position of the third image data sub-region relative to the ending position of the image header information. After obtaining these offsets by decoding the image header information, the starting position of each segment of independently decodeable encoded data can be obtained, so that the LL subband encoded data, HH subband encoded data, HL subband encoded data, and LH subband encoded data can be decoded independently during decoding.

[0280] Optionally, in the example shown in Figure 14A, the offset information may include, but is not limited to: the length information L0 of the first image data region (this length is typically measured in n bytes), the length information L1 of the first image data sub-region, and the length information L2 of the second image data sub-region. L0 is the offset of the starting position of the first image data sub-region relative to the ending position of the image header information. L0 + L1 yields the offset of the starting position of the second image data sub-region relative to the ending position of the image header information. L0 + L1 + L2 yields the offset of the starting position of the third image data sub-region relative to the ending position of the image header information. After obtaining the offset information by decoding the image header information, the starting position of each independently decodeable segment of encoded data can be obtained by addition calculation, so that the LL subband encoded data, HH subband encoded data, HL subband encoded data, and LH subband encoded data can be decoded independently during decoding.

[0281] Referring to Figure 14B, which is an exemplary schematic diagram of an image bitstream structure, in the example of Figure 14B, low-frequency subband coded data is written to the first image data region, and high-frequency subband coded data is written to the second image data region. Further details can be found in Figure 14A, and will not be repeated here.

[0282] Referring to Figure 15, which is an exemplary schematic diagram of an image bitstream structure, in the example of Figure 15, the high-frequency subband encoded data is written to the corresponding image data region according to the type of subband. Specifically, the description of the first image data region and its sub-regions, and the second image data region, can be referred to above and will not be repeated here. Taking HL subband encoded data as an example, the HL subbands of each sub-image (e.g., sub-image 1 to sub-image N) of the image are written to the first image data sub-region; the order is only illustrative.

[0283] In this context, for example, sub-image 1-HL in the figure represents the HL subband encoded data of sub-image 1 of the image. The HL subband encoded data of each sub-image further includes the encoded macroblocks of the HL subband of that sub-image. For example, sub-image 1-HL includes, but is not limited to: sub-image 1-HL-MB0 to sub-image 1-HL-MBm. Sub-image 1-HL-MBx represents the encoded macroblock MBx in the HL subband of sub-image 1. The HH subband encoded data and LH subband encoded data are similar to the HL subband encoded data and will not be described further here.

[0284] Referring again to Figure 15, the LL subband coding data includes, but is not limited to, the LL subband coding data of each sub-image of the image. For example, sub-image 1-LL to sub-image N-LL. Sub-image 1-LL represents the LL subband coding data of sub-image 1 of the image. Each sub-image-LL further includes, but is not limited to, the coding data of each macroblock of that sub-image, i.e., the coded macroblock. For example, sub-image 1-LL includes, but is not limited to, sub-image 1-LL-MB0 to sub-image 1-LL-MBn. Sub-image 1-LL-MBx represents the coding data of macroblock MBx of the LL subband of sub-image 1 of the image.

[0285] For example, during the encoding process, each sub-band of each subgraph is encoded independently; correspondingly, during the decoding process, each encoded sub-band of each subgraph can be decoded independently. In the example shown in Figure 15, it can be understood that the four encoded sub-bands of each subgraph can be decoded independently. For instance, during decoding, the decoder can obtain the HL sub-band encoded data, LH sub-band encoded data, HH sub-band encoded data, and LL sub-band encoded data of subgraph 1 based on the offset information, and perform independent decoding to obtain the decoded subgraph 1.

[0286] In this example, the coded subbands and their coded macroblocks of each sub-image in the figure can also be written into the corresponding image data sub-regions, which are not shown in the figure and will not be repeated below. Accordingly, offset information can be used to indicate the position of the image region to which the independently coded subbands of each sub-image belong. Thus, during decoding, the decoder can obtain the positions of the four coded subbands (LL subband coded data, HH subband coded data, HL subband coded data, and LH subband coded data) of a single sub-image in the image data based on the offset information, and perform decoding on them to obtain the decoded subbands of the corresponding sub-image (including LL subband decoded data, HH subband decoded data, HL subband decoded data, and LH subband decoded data). For example, during decoding, the decoder obtains sub-image 1-HL (including each coded macroblock contained in its sub-region, the same below, and will not be repeated), sub-image 1-HH, sub-image 1-LH, and sub-image 1-LL. In this way, the decoder can obtain the decoded sub-graph 1 based on the above encoded sub-bands without having to decode other sub-graphs one by one according to the order of the bitstream. This can improve decoding efficiency while reducing the occupation of the decoding buffer (e.g., DPB) and reducing the hardware processing pressure and storage burden on the decoding end.

[0287] In one possible implementation, on the encoding side, the low-frequency subband entropy encoding unit can output low-frequency subband encoded data (e.g., LL subband bitstream), and the high-frequency subband entropy encoding unit can output high-frequency subband encoded data (e.g., including HH subband decoded data, HL subband decoded data, and LH subband decoded data). The combining unit writes this data into the image data to generate an image bitstream.

[0288] In another possible implementation, the low-frequency subband entropy coding unit and the high-frequency subband entropy coding unit can also output the coded macroblock of the coded subband to the combining unit after each macroblock is encoded. The combining unit can generate the bitstream structure as shown in the figures (e.g., Figures 15, 16A-16C, 17A-17B, etc.) according to the specified order of the coded macroblocks of the image data.

[0289] Optionally, the subgraph and bitstream structure in Figure 15 can also be applied to the bitstream structures shown in Figures 13B and 14B, and will not be illustrated in detail here.

[0290] In the embodiments of this application, the subbands in the high-frequency subband coded data of the image data can be interleaved and sorted. The interleaving and sorting can be at the sub-image granularity, the subband type granularity, or the macroblock (MB) granularity. Several interleaving and sorting methods are provided below. It should be noted that the interleaving methods shown in the embodiments of this application are only illustrative examples. In other embodiments, other interleaving methods can also be set according to the encoding and decoding requirements.

[0291] Referring to Figure 16A, which is an exemplary schematic diagram of an image bitstream structure, the interleaving method in the example of Figure 16A is interleaving at the subband type of the subimage. Specifically, as shown in Figure 16A, the HL subband encoded data, encoded HH, and encoded LH of each subimage of the image are continuously written into the image bitstream. The subimage order and macroblock order shown in the figure are merely illustrative examples. The format of the low-frequency subband is not shown in the figure; please refer to Figure 15 and its related description, which will not be repeated here.

[0292] For example, as shown in Figure 16A, sub-images 1-HL, 1-HH, and 1-LH are continuously written into the image bitstream. Sub-image 1-HL represents the HL subband encoded data of sub-image 1, which includes, but is not limited to, all encoded macroblocks (MB) of the HL subband of sub-image 1, such as MB0-HL to MBm-HL. Only the bitstream format of sub-image 1 is shown in the figure; other sub-images are similar and will not be described individually here. The LL subband encoded data can be referred to above and will not be repeated here.

[0293] In this example, similar to the description in Figure 15, each coded subband of each sub-image can be decoded independently. Accordingly, offset information can be used to indicate the location of the image region to which the independently coded subband of each sub-image belongs. This allows, during decoding, the positions of the four coded subbands (LL subband coded data, HH subband coded data, HL subband coded data, and LH subband coded data) of a single sub-image can be obtained in the image data based on the offset information, and decoding can be performed on them to obtain the decoded subbands of the corresponding sub-image (including LL subband decoded data, HH subband decoded data, HL subband decoded data, and LH subband decoded data). Details not described herein can be found in Figure 15 and will not be repeated here.

[0294] Referring to Figure 16B, which is an exemplary schematic diagram of the image bitstream structure, the interleaving method in the example of Figure 16B is interleaving at the macroblock level for each sub-image.

[0295] Specifically, in the example shown in Figure 16B, the high-frequency subband encoded data (including LH subband encoded data, HH subband encoded data, and HL subband encoded data) of each sub-image of the image are continuously written into the first image data region. A description of the second image data region can be found in Figure 15, and will not be repeated here.

[0296] For example, as shown in Figure 16B, sub-images 1-HL-MB0, 1-HH-MB0, and 1-LH-MB0 are consecutively written into the first image data region. Here, 1-HL-MB0 represents the encoded macroblock MB0 of the HL subband of 1, 1-HH-MB0 represents the encoded macroblock MB0 of the HH subband of 1, and 1-LH-MB0 represents the encoded macroblock MB0 of the LH subband of 1. The figure only shows the encoded data structure of 1 in the bitstream; the other sub-images are similar and will not be illustrated individually here.

[0297] In this example, during decoding, the decoding end can decode the high-frequency subband encoded data according to the sub-image order, that is, each sub-image in the first image data region is decoded independently. The low-frequency subband encoded data is also decoded according to the sub-image order, that is, each sub-image in the second image data region is decoded independently. Unlike Figures 15, 16A, and 16C, when the bitstream structure in the above figures is applied to decoding, the decoding end decodes the different types of encoded subbands of each sub-image separately. This can also be understood as needing to simultaneously decode the four sub-bitstreams (each sub-bitstream corresponds to one type of encoded subband) of each sub-image to obtain four decoded subbands of an image at the output end, thereby obtaining the decoded sub-image and storing additional data. For the bitstream structure shown in Figure 16B, the decoding end only needs to decode the high-frequency subband and low-frequency subband of each sub-image, that is, two bitstreams. For example, as shown in Figure 16B, when the decoding end decodes the first image data region, it can decode each encoded macroblock one by one according to the encoded macroblock order of each sub-image in the region. That is, the three high-frequency subband encoded data of sub-Figure 1 are written continuously into the first image data area. Therefore, during decoding, the three high-frequency subband encoded data of sub-Figure 1 can be decoded one by one to obtain the decoded high-frequency subband. The processing of LL subband encoded data can be referred to Figure 15, and will not be described in detail here.

[0298] In the example shown in Figure 16B, the offset information is used to indicate the position of the first image data region and the position of the second image data region. That is, the example shown in Figure 16B includes two sub-bitstreams that can be decoded independently. Compared with the framework and decoding methods in Figures 15, 16A, and 16C, it has lower hardware performance requirements, only requiring simultaneous decoding of the two sub-bitstreams of the sub-image (corresponding to low-frequency sub-band encoded data and high-frequency sub-band encoded data).

[0299] Referring to Figure 16C, which is an exemplary schematic diagram of an image bitstream structure, the interleaving method in Figure 16C is based on the sub-bands of each sub-image. Specifically, as shown in Figure 16C, each sub-image of the image is continuously written into the first image data region according to its high-frequency sub-band type. For example, taking sub-image 1 as an example, the coded macroblocks of the HL sub-band encoded data of sub-image 1 are continuously written into the first image data region, that is, sub-image 1-HL-MB0 to sub-image 1-HL-MBm of sub-image 1 are continuously written into the image bitstream. The coded macroblocks of the HH sub-band encoded data of sub-image 1 are continuously written into the first image data region, that is, sub-image 1-HH-MB0 to sub-image 1-HH-MBm of sub-image 1 are continuously written into the image bitstream. The coded macroblocks of the LH sub-band encoded data of sub-image 1 are continuously written into the first image data region, that is, sub-image 1-LH-MB0 to sub-image 1-LH-MBm of sub-image 1 are continuously written into the image bitstream. Other subgraphs are similar and will not be described in detail here. The order of subband types is for illustrative purposes only.

[0300] In this example, similar to the description in Figure 15, each coded subband of each sub-image can be decoded independently. Accordingly, offset information can be used to indicate the location of the image region to which the independently coded subband of each sub-image belongs. This allows, during decoding, the positions of the four coded subbands (LL subband encoded data, HH subband encoded data, HL subband encoded data, and LH subband encoded data) of a single sub-image can be obtained in the image data based on the offset information, and decoding can be performed on them to obtain the decoded subbands of the corresponding sub-image (including LL decoded data, HH decoded data, HL decoded data, and LH decoded data). Parts not described herein can be referred to Figure 15 and will not be repeated here.

[0301] For example, in the example of Figure 16C, during decoding, the decoder obtains the HH subband encoded data, LH subband encoded data, HL subband encoded data, and LL subband encoded data of sub-Figure 1 from the image bitstream based on offset information (not shown in Figure 16C, see Figure 15). The decoder decodes the encoded data of the four subbands of sub-Figure 1 to obtain the reconstructed sub-Figure 1, which can also be called decoded sub-Figure 1 or decoded sub-Figure 1.

[0302] In the embodiments of this application, multiple independently decoded encoded data can be decoded simultaneously, or one or more high-frequency subbands can be decoded simultaneously, and the number of simultaneous decodes depends on the decoder hardware performance.

[0303] Referring to Figure 17A, which is an exemplary schematic diagram of an image bitstream structure, the interleaving method in the example of Figure 17A is granular at the low-frequency and high-frequency subbands of the subgraph. Only the interleaving method of subgraph 1 is shown; other subgraphs are similar and will not be described in detail here. For example, the structure of the low-frequency subband encoded data of the subgraph can be seen in Figure 15, and will not be repeated here. In one example, the structure of the high-frequency subband encoded data of the subgraph can use any of the interleaving methods for high-frequency subband encoded data in Figures 16A to 16C.

[0304] Referring to Figure 17B, which is an exemplary schematic diagram of the bitstream structure, in the example of Figure 17B, the splicing order of the sub-graphs can be low-frequency subband coded data followed by high-frequency subband coded data. Other descriptions can be found in Figure 17A, and will not be repeated here.

[0305] Optionally, for the examples shown in Figures 17A and 17B, the offset information in the image header information is also used to indicate each encoded data that can be decoded independently. The indication method can be seen in Figures 15 and 16A to 16C, which will not be repeated here.

[0306] Referring to Figure 18, which is a schematic / conceptual block diagram of an exemplary decoder, in the example of Figure 18, the decoder receives, for example, an image bitstream encoded by an encoder to obtain a decoded image of the original image, also referred to as a decoded image, reconstructed image, etc. During the decoding process, the decoder receives the image bitstream from the encoder, including, but not limited to, image header information and image data. The image bitstream can be any of the bitstream formats shown in Figures 13A to 17B.

[0307] In the example shown in Figure 18, the decoder includes, but is not limited to: low-frequency subband processing path 1810, high-frequency subband processing path 1820, wavelet inverse transform unit 1830, image combination unit 1840 (also known as image stitching unit), etc.

[0308] For example, the low-frequency subband processing path 1810 is used to acquire low-frequency subband encoded data to obtain reconstructed low-frequency subband 1806 (also known as decoded low-frequency subband). The low-frequency subband processing path includes, but is not limited to: low-frequency subband entropy decoding unit 1811, inverse quantization / inverse transform unit 1812 (also known as low-frequency subband inverse quantization / inverse transform unit), low-frequency subband reconstruction unit 1813, low-frequency subband splicing unit 1815, prediction unit 1814, etc.

[0309] The high-frequency subband processing path 1820 is used to acquire high-frequency subband encoded data to obtain the reconstructed high-frequency subband 1831, which can also be called the reconstructed value of the high-frequency subband or the reconstructed data of the high-frequency subband, including but not limited to: high-frequency subband entropy decoding unit 1821, inverse quantization / inverse transform unit 1821 (also called high-frequency subband inverse quantization / inverse transform unit), high-frequency subband reconstruction unit 1831, etc.

[0310] In some instances, the decoder shown in Figure 18 can perform a decoding process that is largely the reverse of the encoding process described with reference to the encoder in Figure 12.

[0311] The decoding method in the embodiments of this application will be described in detail below with reference to the decoder 180 shown in Figure 18.

[0312] For example, the decoder 180 can obtain high-frequency subband encoded data and low-frequency subband encoded data in the image bitstream based on the image header information in the image bitstream. Furthermore, as described above, during the encoding process, the encoder uses macroblocks as the basic encoding unit, and correspondingly, during the decoding process, the decoder also uses macroblocks (e.g., encoded macroblocks) as the basic decoding unit for decoding.

[0313] For example, the low-frequency subband entropy decoding unit 1811 performs entropy decoding on the low-frequency subband encoded data 1801 in the image bitstream, using macroblocks as the basic decoding unit, to obtain the quantization coefficients 1802 (i.e., the quantization coefficients of the current macroblock) and syntax elements 1807 of the low-frequency subband block. The description of the quantization coefficients 1802 of the low-frequency subband can be found on the encoder side and will not be repeated here. Specifically, the low-frequency subband entropy decoding unit 1811 obtains the encoded macroblocks (i.e., the encoded data of the macroblocks) of the low-frequency subbands (e.g., LL subbands) of each sub-image in the image bitstream, and performs entropy decoding on each encoded macroblock to obtain the quantization coefficients 1802 (which can be simply referred to as the quantization coefficients of the macroblock of the low-frequency subband) and syntax elements 1807 of the corresponding low-frequency subband for each encoded macroblock. During the decoding process, the currently decoded encoded macroblock can be called the current block.

[0314] The low-frequency subband decoding unit is used to output the quantization coefficients 1802 of the low-frequency subband block to the inverse quantization / inverse transform unit 1812, and to output the syntax elements 1807 to the prediction unit 1814.

[0315] The inverse quantization / inverse transform unit 1812 is used to obtain the quantization coefficients 1802 of the low-frequency subband block to obtain the inverse quantization coefficients 1803 of the low-frequency subband block. Alternatively, it can be the inverse transform coefficients of the current block of the low-frequency subband (depending on whether inverse transform processing was performed). Specifically, the inverse quantization / inverse transform unit 1812 performs inverse quantization on the quantization coefficients of the current block of the low-frequency subband, or performs both inverse quantization and inverse transform, to obtain the inverse quantization coefficients of the current block of the low-frequency subband. The inverse quantization / inverse transform unit 1812 outputs the inverse quantization coefficients 1803 of the low-frequency subband block to the low-frequency subband reconstruction unit 1813, for example, the inverse quantization coefficients of the current block of the low-frequency subband.

[0316] The low-frequency subband reconstruction unit 1813 is used to obtain the low-frequency subband reconstruction block 1804, which can also be called the reconstruction coefficient of the low-frequency subband block, based on the quantization coefficients 1803 and prediction block 1805 of the low-frequency subband. Specifically, the low-frequency subband reconstruction unit 1813 adds a prediction block to the inverse quantization coefficients of the current block of the low-frequency subband to obtain the low-frequency subband reconstruction block 1804 corresponding to the current macroblock.

[0317] The prediction unit 1814 is used to obtain syntax element 1807 and perform corresponding prediction processing according to syntax element 1807. For example, intra-frame prediction can be performed based on low-frequency subband reconstruction block 1804, or inter-frame prediction can be performed based on reconstructed low-frequency subband 1806. Its execution method can be referred to the coding side, and will not be elaborated here. The prediction unit 1814 outputs prediction block 1805 to the low-frequency subband reconstruction block 1804 unit.

[0318] For example, the high-frequency subband entropy decoding unit 1821 acquires the high-frequency subband encoded data 1802 in the image bitstream, and, using macroblocks as the basic decoding unit, acquires the quantization coefficients 1808 (which are the quantization coefficients of the current macroblock) of each high-frequency subband block. Specifically, the high-frequency subband entropy decoding unit 1821 performs entropy decoding on the current block of the high-frequency subband encoded data 1802 to obtain the quantization coefficients of the current block of the high-frequency subband. Optionally, based on entropy decoding, the syntax elements corresponding to the current block can also be obtained. The high-frequency subband entropy decoding unit 1821 outputs the quantization coefficients 1808 of the high-frequency subband block to the inverse quantization / inverse transform unit 1822.

[0319] The inverse quantization / inverse transform unit 1822, also known as the high-frequency subband inverse quantization / inverse transform unit, is used to obtain the quantization coefficients 1808 of the high-frequency subband block to obtain the reconstruction coefficients 1809 of the high-frequency subband block. The reconstruction coefficients can be either inverse quantization coefficients after inverse quantization processing, or inverse transform coefficients after inverse quantization and inverse transform processing.

[0320] The high-frequency subband reconstruction unit 1823 (also known as the high-frequency subband splicing unit) is used to obtain the reconstruction coefficients 1809 of the high-frequency subband block to obtain the reconstructed high-frequency subband 1831, which can also be referred to as the reconstructed value or reconstructed data of the high-frequency subband. Specifically, the high-frequency subband reconstruction unit 1823 can obtain the reconstruction coefficients corresponding to each macroblock of the high-frequency subband, that is, reconstruct the high-frequency subband block. The high-frequency subband reconstruction unit 1823 can splice the obtained multiple macroblocks to obtain the corresponding high-frequency subband. Among them, the reconstructed high-frequency subband may optionally include reconstructing the HL subband (e.g., the reconstruction coefficients of the HL subband), reconstructing the HH subband (e.g., the reconstruction coefficients of the HH subband), and reconstructing the LH subband (e.g., the reconstruction coefficients of the LH subband).

[0321] The inverse wavelet transform unit 1830 is used to acquire the reconstructed high-frequency subband 1831 and the reconstructed low-frequency subband 1806 to obtain the reconstructed sub-image 1832. Specifically, the inverse wavelet transform unit 1830 acquires the reconstructed low-frequency subband 1806 output by the low-frequency subband stitching unit 1815 and the reconstructed high-frequency subband 1831 output by the high-frequency subband reconstruction unit 1823, and performs an inverse wavelet transform on the reconstructed low-frequency subband 1806 and the reconstructed high-frequency subband 1831 to obtain the reconstructed sub-image 1832. The inverse wavelet transform unit 1830 outputs the reconstructed sub-image 1832 to the image combining unit (which may also be called the image stitching unit, etc.).

[0322] Image combining unit 1840 is used to acquire reconstructed sub-images 1832 to obtain a reconstructed image 1833 of the original image, which can also be called a decoded image or a decoded image, etc. Specifically, image combining unit 1840 can acquire N reconstructed sub-images (N is an integer greater than 0) of the image (referring to the original image), and stitch (or combine) the N reconstructed sub-images according to the division method (including size and position) of each reconstructed sub-image during encoding to obtain the reconstructed image 1833.

[0323] Optionally, after obtaining the reconstructed image, the image combining unit 1840 can determine whether the reconstructed image contains a padding portion based on the image size information in the image header information and the size information of the current reconstructed image. In one example, if the size of the current reconstructed image is the same as the size indicated by the image size information (i.e., the same as the original image size), the image combining unit 1840 can send the reconstructed image to the display device. In this case, the sizes of the displayed image, the original image, and the reconstructed image are all the same. In another example, if the size of the current reconstructed image is different from the size indicated by the image size information (e.g., larger than the original image size), the image combining unit 1840 can remove the padding portion of the current reconstructed image based on the size indicated by the image size information to obtain the displayed image. The size of the displayed image is the same as the size of the original image. Specifically, in this embodiment, when the encoding side performs sub-image division, the division order is preset, usually from left to right in the horizontal direction and from top to bottom in the vertical direction. Correspondingly, at least one padding sub-image is usually located at the edge of the image, as shown in Figure 9B. For example, the image combining unit 1840 may crop the vertical and / or horizontal edges of the image according to the size information to remove the fill portion of the sub-image at the edge.

[0324] Optionally, in some instances, the image reconstruction unit may also perform the above-mentioned operation of removing the padding portion during the process of acquiring the reconstructed image, so that the size of the reconstructed image is the same as the size of the original image.

[0325] Optionally, the decoder is used, for example, to output a reconstructed image via the decoder's output port (or output interface) for presentation to or viewing by the user.

[0326] Other variations of the decoder can be used to decode compressed image bitstreams.

[0327] For example, as described above, each sub-image in the image bitstream may include two or four independently decodeable encoded data. For instance, in the examples shown in Figures 15, 16A, and 16C, the encoded HH sub-band, encoded LH sub-band, encoded HL sub-band, and encoded LL sub-band of each sub-image can be independently decoded. In the above scenario, the high-frequency sub-band entropy decoding unit can obtain each independently decodeable image data region based on the offset information in the image header information, and obtain the encoded data within the image data region. The high-frequency sub-band entropy decoding unit can simultaneously decode the encoded data of one or more independently decoded image data regions.

[0328] Optionally, in the above scenario, the high-frequency subband processing path may include at least one high-frequency processing subpath (not shown in the figure). For example, the high-frequency subband processing path may include three high-frequency processing subpaths to process three coded subbands of a subgraph simultaneously. Of course, in some instances, there may be more than three or fewer high-frequency subband processing subpaths. The more high-frequency subband processing paths there are, the higher the decoding efficiency. The fewer the paths, the lower the hardware design complexity requirements.

[0329] The decoding method is illustrated below using the bitstream structure shown in Figure 16A. In the example shown in Figure 16A, the low-frequency entropy decoding unit 1801 acquires the LL subband encoded data and performs decoding based on macroblocks. Taking sub-Figure 1 as an example, the low-frequency entropy decoding unit 1801 acquires the LL subband encoded data of sub-Figure 1 and decodes each encoded macroblock. The low-frequency subband decoding path 1810 processes the current block (inverse quantization / inverse transform, prediction, reconstruction, etc.) to output the reconstructed low-frequency subband of sub-Figure 1 to the wavelet inverse transform unit.

[0330] The high-frequency subband entropy decoding unit 1821 acquires LH subband encoded data, HL subband encoded data, and HH subband encoded data, and performs decoding based on the encoded macroblocks. Taking sub-image 1 as an example, specifically, the high-frequency entropy decoding unit 1821 acquires the LH subband encoded data, HL subband encoded data, and HH subband encoded data of sub-image 1 in the image bitstream based on offset information. The acquisition order can be in the order of the bitstream or according to actual needs. The high-frequency subband processing path 1820 processes the decoded macroblocks of sub-image 1 output by the high-frequency subband entropy decoding unit. In one example, the high-frequency subband entropy decoding unit can optionally decode the LH subband encoded data, HL subband encoded data, and HH subband encoded data of sub-Figure 1 simultaneously. The high-frequency subband processing path obtains multiple decoded high-frequency subbands output by the high-frequency subband entropy decoding unit and processes each macroblock in the multiple decoded high-frequency subbands simultaneously to output the reconstructed HH subband, reconstructed HL subband, and reconstructed LH subband of sub-Figure 1 to the wavelet inverse transform unit.

[0331] In another example, the high-frequency subband entropy decoding unit can optionally decode the LH, HL, and HH subband encoded data of sub-Figure 1 simultaneously. The high-frequency subband processing path acquires multiple decoded high-frequency subbands output by the high-frequency subband entropy encoding unit. It can process each macroblock in at least one decoded high-frequency subband, and the decoded data of other received but unprocessed high-frequency subbands can be cached in storage. The processing order can follow the order in the bitstream or be set according to actual needs. Similarly, the high-frequency subband processing path outputs to the wavelet inverse transform unit after acquiring a reconstructed high-frequency subband of sub-Figure 1.

[0332] After the wavelet inverse transform unit obtains the four reconstructed high-frequency subbands of sub-figure 1, including the reconstructed LL subband, reconstructed HL subband, reconstructed HH subband, and reconstructed LH subband, it performs wavelet inverse transform to obtain the reconstructed sub-figure 1.

[0333] Optionally, before acquiring the four reconstructed high-frequency subbands of sub-graph 1, the wavelet inverse transform unit can cache each reconstructed subband acquired. After acquiring all the reconstructed high-frequency subbands of sub-graph 1, it can acquire the cached reconstructed high-frequency subbands of sub-graph 1 and perform the wavelet inverse transform.

[0334] It can be understood that, in the embodiments of this application, when the high-frequency subband processing path and the low-frequency subband processing path process the encoded data of the sub-graph, the order of the sub-graphs and their macroblocks in each independent decoded data is the same. For example, as shown in Figure 15, the high-frequency subband entropy decoding unit can obtain the HH subband encoded data, HL subband encoded data, and LH subband encoded data of a single sub-graph (e.g., sub-graph 1) from the offset. In this way, when decoding, the high-frequency subband entropy decoding unit can obtain each encoded subband and its encoded macroblock of sub-graph 1 to decode sub-graph 1. Correspondingly, the high-frequency subband processing path can process the decoded macroblocks corresponding to the high-frequency subbands of sub-graph 1 to obtain each reconstructed high-frequency subband of sub-graph 1 and output it to the wavelet inverse transform unit so that the wavelet inverse transform unit can output the reconstructed sub-graph 1. In this way, the wavelet inverse transform unit only needs to buffer the decoded data of sub-graph 1 during the processing. If the high-frequency processing unit processes the encoded data in the code stream as shown in Figure 15, the wavelet inverse transform unit will cache the reconstructed HL subbands of other sub-graphs before obtaining the reconstructed HH subband of sub-graph 1, which increases the storage burden and requires a large hardware cache space, affecting the complexity of hardware design.

[0335] For example, in the example shown in Figure 16B, the high-frequency subband encoded data in the image bitstream is interleaved at the MB granularity. That is, during decoding, the high-frequency subband encoded data and low-frequency subband encoded data of each sub-image can be decoded independently. The high-frequency subband processing path can process each macroblock according to the order of the encoded macroblocks of the sub-image in the image bitstream, that is, the reconstructed subbands of each sub-image are obtained according to the order of the sub-images, which can reduce the hardware design complexity of the decoding end.

[0336] Referring to Figure 19, which is an exemplary schematic / conceptual block diagram of a decoder, the decoder 190 includes, but is not limited to: a low-frequency subband processing path 1910, a high-frequency subband processing path 1920, a wavelet inverse transform unit 1930, a sub-image combination unit 1940, and an image combination unit 1950. The low-frequency subband processing path 1910 includes, but is not limited to: a low-frequency subband entropy coding unit 1911, an inverse quantization / inverse transform unit 1912, a low-frequency subband reconstruction unit 1913, a low-frequency subband stitching unit 1915, and a prediction unit 1914. Detailed descriptions can be found in Figure 18, and will not be repeated here. The descriptions of the input and output coefficients or data of each unit (such as low-frequency subband coding data 1901, low-frequency subband quantization coefficients 1902, low-frequency subband inverse quantization coefficients 1903, low-frequency subband reconstruction block 1904, reconstructed low-frequency subband 1906, prediction block 1905, and syntax element 1907) can be found in Figure 18, and will not be repeated here.

[0337] The high-frequency subband processing path 1920 includes, but is not limited to: high-frequency subband entropy coding unit 1921, inverse quantization / inverse transform unit 1922, and high-frequency subband reconstruction unit 1923.

[0338] The high-frequency subband entropy coding unit 1921 obtains the quantization coefficients 1908 of the high-frequency subband block based on the high-frequency subband coded data 1902. The inverse quantization / inverse transform unit 1922 obtains the reconstruction coefficients 1909 of the high-frequency subband block based on the quantization coefficients 1908 of the high-frequency subband block, which can also be called the high-frequency subband reconstruction block.

[0339] The wavelet inverse transform unit 1903 is used to obtain the reconstruction coefficients 1909 of the high-frequency subband block, i.e., the high-frequency subband reconstruction block, and the low-frequency subband reconstruction block 1904 output by the low-frequency subband reconstruction block unit 1913. The wavelet inverse transform is performed on the high-frequency subband reconstruction block (e.g., including HH subband reconstruction block, HL subband reconstruction block, LH subband reconstruction block) and the low-frequency subband reconstruction block 1904 to obtain the reconstruction block 1931, which is the reconstruction block of the current subgraph. It can also be called the reconstruction data of the current block of the current subgraph or the reconstruction value of the current block of the current subgraph.

[0340] The wavelet inverse transform unit 1930 outputs a reconstructed block 1931 to the subgraph combination unit 1940. The subgraph combination unit 1940 can obtain the reconstructed subgraph of the current subgraph based on at least one reconstructed block corresponding to the current subgraph, which can also be referred to as the reconstructed value or reconstructed data of the current subgraph.

[0341] Subgraph combining unit 1940 outputs reconstructed subgraph 1932 to image combining unit 1950.

[0342] The image combination unit 1950 is used to acquire the reconstructed sub-image 1932 to obtain the reconstructed image 1933 of the original image, or the reconstructed value or reconstructed data of the original image, etc. The undescribed parts of Figure 19 can be referred to Figure 18, and will not be repeated here.

[0343] Figure 20 is a schematic diagram of the framework of an edge-cloud collaborative system provided in an embodiment of this application. The edge-cloud collaborative system may include: a central server, edge servers, and clients; wherein, a central server may be connected to one or more edge servers, and an edge server may be connected to one or more clients. This application does not limit the number of edge servers and clients; the specific number can be flexibly set according to the application scenario.

[0344] For example, a client can access the network through wireless access points such as base stations or Wi-Fi access points and communicate with the edge server through the network, or the client and the edge server can also communicate through a wired connection. Similarly, the edge server can also access the network through wireless access points such as base stations or Wi-Fi access points and communicate with the central server through the network, or the edge server and the central server can also communicate through a wired connection.

[0345] For example, the central server can be a single server, a server cluster consisting of multiple servers, or other distributed systems; this application does not impose any restrictions on this.

[0346] The client can be software, applications, browsers, in-vehicle systems, terminal devices, etc. When the client is implemented as a terminal device, it can include, but is not limited to, the following as shown in Figure 20: mobile phone, personal computer (PC), virtual reality (VR) device, augmented reality (AR) device, tablet computer, laptop computer, etc. The client can also be a smart TV, mobile internet device (MID), wearable device (such as smartwatch, smart glasses, or smart helmet), smart car, wireless terminal device in industrial control, wireless terminal device in self-driving, wireless terminal device in remote medical surgery, wireless terminal device in smart grid, wireless terminal device in transportation safety, wireless terminal device in smart city, wireless terminal device in smart home, etc. The following embodiments do not impose special limitations on the specific form of the client.

[0347] In one possible scenario, some clients may connect directly to the central server instead of the edge server; in another possible scenario, all clients may connect directly to the central server instead of the edge server.

[0348] Furthermore, the edge-cloud collaborative system framework shown in Figure 20 is only an example of the edge-cloud collaborative system framework of this application. In the edge-cloud collaborative system of this application, the central server and the edge server can also be the same server; or the edge-cloud collaborative system of this application does not include edge servers, but the central server connects with each client. This application does not impose any restrictions on this.

[0349] As shown in Figure 20, the edge-cloud collaborative system can be applied to various image encoding and decoding scenarios of edge-cloud collaboration, such as cloud gaming, cloud exhibitions, 3D cloud conferencing, 3D scenes, interior decoration, clothing design, architectural design and other multi-terminal collaborative image encoding and decoding scenarios. This application does not limit this.

[0350] In some embodiments, this application provides an encoding method and a decoding method. The functionality of the encoding method can be implemented by at least one of a server and a client, and the functionality of the decoding method can be implemented by at least one of a server and a client.

[0351] This server can be implemented through software or hardware.

[0352] In the first example, when the functionality of the server is implemented through software, the server may be, for example, an application running on a computing instance (such as an encoder or decoder, or an application that implements the encoding and decoding methods of this application), which may be, for example, a virtual machine, a container, or a host.

[0353] In the second example, when the server functionality is implemented through hardware, the server can be implemented through at least one physical device including a processor. This physical device can be a server (e.g., a central server or an edge server), a base station, a relay device, satellite equipment, etc., and there are no restrictions on this.

[0354] The processor can be a central processing unit (CPU) or a graphics processing unit (GPU), or it can be any type of processor or any combination thereof, such as an application-specific integrated circuit (ASIC), a programmable logic device (PLD), a complex programmable logical device (CPLD), a field-programmable gate array (FPGA), a generic array logic (GAL), a system-on-chip (SoC), a software-defined infrastructure (SDI) chip, an AI chip, or a data processing unit (DPU).

[0355] Furthermore, the number of processors included in the server can be arbitrary, and the types of processors included can be one or more. The specific number and types of processors can be set according to the actual business needs of the application, and this application does not impose any restrictions on this.

[0356] In the third example, when the server-side functionality is implemented through hardware, the server can also be a computing cluster comprising multiple computing nodes. Furthermore, these multiple computing nodes can communicate through the at least one switching node. Exemplarily, a computing node can be a computing server including an accelerator card. This accelerator card can be, for example, a deep-learning processing unit (DPU), a GPU, a neural-network processing unit (NPU), or a tensor processing unit (TPU), or other types of accelerator cards. Alternatively, a computing node can be a computing server including a general-purpose processor (such as a CPU).

[0357] The encoding method provided in this application can be applied to any encoder, and the decoding method provided in this application can be applied to any decoder. The encoder and decoder can be standard video encoders and standard video decoders. These standard video encoders and decoders can be implemented according to industry video compression standards, such as ITU-T H.264, H.265 / HEVC, H.266 / VVC, AVS2, AVS3 standards, or extensions of such standards. The solutions in this application are not limited to any specific encoding / decoding standard.

[0358] The encoding and decoding method provided in this application embodiment can be combined with the encoding and decoding method of any of the above embodiments. In addition, the encoding and decoding method in this application embodiment can be applied to the encoding and decoding of images and videos in any intra-frame prediction scenario.

[0359] The following example illustrates the encoding and decoding methods of this application by using an encoder to execute the encoding method and a decoder to execute the decoding method. However, this application does not limit the subject that executes the encoding and decoding methods of this application.

[0360] The method in this application embodiment can encode and decode the current block in a video or image in intra-frame prediction mode.

[0361] In some embodiments, the intra-frame prediction mode may include at least one of the following: direct current (DC) mode, vertical mode, horizontal mode, planar mode, and cross-component linear model (CCLM) mode.

[0362] In some embodiments, each sample point in the block may include three components: Y, UV, and chromaticity. The Y component is the luminance component, and the UV components are the chromaticity components.

[0363] In some embodiments, the intra-frame prediction mode for the luminance component may include at least one of the following: DC mode, vertical mode, horizontal mode, and Planar mode.

[0364] In some embodiments, the intra-frame prediction mode of the chroma component may include at least one of the following: DC mode, vertical mode, horizontal mode, and CCLM mode.

[0365] In some embodiments, when the current block is encoded and decoded using intra-frame prediction mode, this application provides an encoding and decoding method that differs from traditional encoding and decoding methods.

[0366] The encoding method of this application embodiment will be illustrated below with different examples.

[0367] Example A3

[0368] In conjunction with the encoding methods of any of the above embodiments, this application also provides an encoding method, which can also be combined with the above-mentioned encoding methods with wavelet transform (also known as wavelet forward transform) (such as the encoding methods involved in any of the embodiments in Figures 6 to 19).

[0369] Figure 21 illustrates a flowchart of an encoding method according to this application. As shown in Figure 21, the method flow may include, but is not limited to, the following steps:

[0370] Optionally, S101a. Obtain the current block in the current frame.

[0371] In some embodiments, the current block is block data obtained after wavelet transform and adjustment operations.

[0372] In an optional embodiment, the parameters of the adjustment operation include at least one of a first adjustment parameter and a second adjustment parameter, wherein the first adjustment parameter is used to adjust the data precision of the current block, and the second adjustment parameter is used to adjust the data range of the current block after wavelet transform.

[0373] In some embodiments, adjustment based on a first adjustment parameter may be referred to as "precision adjustment" and adjustment based on a second adjustment parameter may be referred to as "range adjustment". In this case, the adjustment operation may include at least one of precision adjustment and range adjustment.

[0374] For example, the first adjustment parameter is used to improve the data accuracy of the current block, and the second adjustment parameter is used to change the data range of the current block after wavelet transform. For example, the data range changes from range 1 to range 2, and the data lengths of range 1 and range 2 are the same.

[0375] In some embodiments, a wavelet transform (also known as a forward wavelet transform) may be performed on the current block before intra-frame prediction is performed on the current block.

[0376] In some embodiments, the precision of the current block may be adjusted before performing a wavelet transform on the current block.

[0377] In some embodiments, the current block can be range-adjusted after wavelet transform is performed on the current block.

[0378] In optional embodiments, the encoder can determine the first adjustment parameter based on different levels of precision. For example, the higher the precision, the larger the determined first adjustment parameter; the lower the precision, the smaller the determined first adjustment parameter. In some embodiments, the number of bits shifted left can be 2 to 4 bits to improve data precision with lower complexity.

[0379] S101b. Obtain the first data.

[0380] In some embodiments, if the reference block corresponding to the current block is unavailable, the encoder may acquire the first data.

[0381] In an optional embodiment, the first data is obtained by adjusting the second data based on the parameters of the aforementioned adjustment operation, and the second data is preset reference data. In a specific embodiment, the encoder can adjust the preset reference data based on the parameters of the adjustment operation to obtain the first data.

[0382] In an optional embodiment, the parameters of the adjustment operation may include at least one of a first adjustment parameter and a second adjustment parameter.

[0383] In some embodiments, the reference block is the reference block corresponding to the intra-prediction mode of the current block; however, the decoded block in the image to be encoded is different from the reference block.

[0384] The following explains various scenarios where the reference block corresponding to the current block cannot be obtained (hereinafter referred to as the reference block of the current block being unavailable):

[0385] For example, a reference block for the current block may exist in the coded blocks within the current frame. However, the reference block existing in the current frame is not the reference block corresponding to the current block in the intra-frame prediction mode, making it impossible to obtain the reconstruction data of the reference block corresponding to the current block in the intra-frame prediction mode.

[0386] Alternatively, there may be a reference block in the current frame that corresponds to the intra-prediction mode of the current block. However, this reference block has not been encoded or decoded and reconstructed before the current block, so the reconstructed data of the reference block cannot be obtained (this is also a scenario where the reference block of the current block is unavailable).

[0387] Alternatively, any block in the current frame (whether or not it has been encoded) is not the reference block corresponding to the intra-prediction mode of the current block, and the reconstruction data of the reference block corresponding to the current block in the intra-prediction mode cannot be obtained (which is also a scenario where the reference block of the current block is unavailable).

[0388] In scenarios where the reference block for the current block is unavailable, preset reference data can be obtained as the reference block for the intra-prediction mode of the current block. However, since the current block undergoes wavelet transform and the aforementioned adjustment operations during intra-prediction, to ensure that the reference data for the current block is in the same dimension as the current block, the preset reference data can be adjusted using the parameters of the aforementioned adjustment operations (i.e., the parameters used when the current block is adjusted), thereby obtaining first data. This first data, after the adjustment operation, can be used as the reference block for the current block in intra-prediction. Thus, when performing intra-prediction on the current block, the data dimension of the current block is the same as the data dimension of the first data serving as the reference block, thereby improving the accuracy of the intra-prediction prediction data and consequently improving the coding accuracy.

[0389] In the embodiment of FIG21, the adjustment operation includes precision adjustment and range adjustment as an example. In other embodiments, the adjustment operation may include either precision adjustment or range adjustment. However, the adjustment operation performed on the preset reference data is the same as the adjustment operation performed on the current block.

[0390] In some embodiments, when performing an adjustment operation on preset reference data, the order in which the adjustment parameters (at least one of the first adjustment parameter and the second adjustment parameter) are used is consistent with the order in which the adjustment parameters are used when the current block is performing the adjustment operation.

[0391] This ensures that the first data obtained after adjusting the preset reference data is used as the reference data for intra-frame prediction of the current block, and that the data of the current block is in the same dimension as the first data, thereby ensuring the accuracy of intra-frame prediction.

[0392] In the embodiment shown in Figure 21, taking the adjustment operations that the current block has undergone as an example, which include precision adjustment and range adjustment in sequence, the first data is obtained by adjusting the preset reference data in sequence according to the first adjustment parameter and the second adjustment parameter respectively.

[0393] In some embodiments, the preset reference data may be subjected to precision adjustment (e.g., precision adjustment according to a first adjustment parameter) and range adjustment (e.g., range adjustment based on a second adjustment parameter) in sequence to obtain the first data.

[0394] When the current block undergoes the above adjustment operation, the precision adjustment and the range adjustment are performed sequentially, so that the order of precision adjustment and range adjustment of the current block's adjustment operation is consistent with the order of precision adjustment and range adjustment of the preset reference data.

[0395] In this embodiment, the current block or preset reference data is first adjusted in precision, then adjusted in range. Precision adjustment improves the precision of the adjusted data, allowing the adjusted current block or preset reference data to retain higher precision for intra-frame prediction and coding, thereby improving the accuracy of the intra-frame prediction data. Performing range adjustment after precision adjustment ensures that the current block and the first data used for intra-frame prediction are of the same dimension.

[0396] In some embodiments, the first data is obtained by shifting the preset reference data to the left according to the first adjustment parameter, and by adding an offset to the second data after the left shift according to the second adjustment parameter.

[0397] In some embodiments, the preset reference data can be shifted to the left according to the first adjustment parameter to obtain the left-shifted preset reference data; then, the left-shifted preset reference data can be increased by an offset according to the second adjustment parameter to obtain the first data.

[0398] For example, in binary data, shifting left by 1 bit is equivalent to multiplying by 2, for instance, if the default reference data before the left shift is 2. 9 For example, if the first adjustment parameter is to shift left by 2 bits, then the preset reference data after the left shift is 2. 11 This improves the accuracy of the preset reference data. Then, for example, the second adjustment parameter is increased by 2. 11 Then the preset reference data 2 after shifting to the left can be used. 11 Increase offset (here it is 2) 11 ), to obtain the first data (specifically 2) 12 ).

[0399] In some embodiments, the second adjustment parameter may be specifically used to adjust the data range of the current block after wavelet transform to a positive data range.

[0400] For example, the data range of the current block after wavelet transform is Where R is 2 12 The second adjustment parameter can then be an increase in the specific offset. That is, increase the offset to 2. 11 To increase the data range This makes the data range of the current block after adjustment by the second adjustment parameter [0, 2R]. After the current block is transformed by wavelet transform and then adjusted according to the second adjustment parameter, the data range of the current block after adjustment is [0, 2R]. This data range is a range of positive numbers.

[0401] In some embodiments, the data range of the current block after wavelet transform is a negative data range, such as the one described above. A negative data range indicates that the minimum value in the data range is negative. Therefore, when representing the data of the current block after wavelet transform, a sign bit is needed to represent the negative value, resulting in a long bit width for the current block after wavelet transform. This leads to the current block occupying a long bit width when used for intra-frame prediction (or inter-frame prediction). To address this, the encoder in this embodiment can adjust the data range of the current block after wavelet transform from a negative data range to a positive data range. This positive data range indicates that the minimum value in the data range is zero or a positive number. Thus, when representing the data of the current block after range adjustment using the second adjustment parameter (e.g., in binary data), only the data of the current block needs to be represented, without occupying at least one bit (e.g., a sign bit) to represent the negative value. This reduces the data bit width of the current block for intra-frame prediction (or inter-frame prediction), improving prediction and coding efficiency.

[0402] The above embodiment uses 0 as an example to illustrate the concept. In other embodiments, the minimum value in the positive number range can also be a number greater than 0 (e.g., 2). 11 -1). Thus, the second adjustment parameter can be changed, and is not limited to the data range used to adjust the data range of the current block after wavelet transform to the data range with a minimum value of 0.

[0403] Furthermore, in the above embodiments, the data range of the current block after wavelet transform is as described above. For example, if the goal of range adjustment is to make the minimum value of the data range of the current block after adjustment 0, then the second adjustment parameter is to increase... That is, the offset is In some embodiments, the data range of the current block after wavelet transform can be a data range greater than 0 (e.g., For example, if the goal of range adjustment is to make the minimum value of the data range of the current block after adjustment 0, then the second adjustment parameter is to subtract... That is, offset is Make the data range of the current block after range adjustment to be

[0404] Of course, if the goal of range adjustment is that the minimum value of the data range of the current block after adjustment (i.e., the left boundary value of the data range) is greater than 0, the second adjustment parameter can also be changed based on this goal to meet the adjustment goal, which will not be elaborated here.

[0405] Thus, when the second adjustment parameter is to increase the offset, the offset can be either positive or negative, as long as the data of the current block after increasing the offset meets the target of the adjustment operation.

[0406] S102. Based on the first data, perform intra-frame prediction on the current block after the above wavelet transform and adjustment operation to obtain the predicted value of the current block.

[0407] In an optional embodiment, the encoder may decide on the intra-prediction mode to be used for the current block, and perform intra-prediction on the current block based on the first data according to the intra-prediction mode to obtain the predicted value of the current block.

[0408] In some embodiments, the intra-prediction mode (also referred to as the first intra-prediction mode) on the chroma component can be one of the following: vertical mode, horizontal mode, DC mode, and CCLM mode.

[0409] In some embodiments, the intra-prediction mode (also referred to as the second intra-prediction mode) on the luminance component can be one of the following: vertical mode, horizontal mode, DC mode, and planar mode.

[0410] S103. Encode the current block based on the predicted value to obtain the bitstream.

[0411] In some embodiments, as shown in FIG21, the current block obtained in S101a is block data after precision adjustment and range adjustment. When encoding the current block based on the predicted value of the current block obtained in S102, the block data of the current block (hereinafter also referred to as the actual value) and the predicted value are both after precision adjustment and range adjustment, so that they are in the same dimension, thereby obtaining the residual, and encoding the residual to obtain the bitstream of the image to be encoded.

[0412] In conjunction with any of the above embodiments, in an optional embodiment, FIG22 exemplarily illustrates a flowchart of another encoding method according to an embodiment of this application. As shown in FIG22, the method flow may also include, but is not limited to, the following steps:

[0413] S121. Perform wavelet transform on the image or video to be encoded to obtain the low-frequency subband.

[0414] The image to be encoded can be the original image or a sub-image obtained by sub-image partitioning; there are no restrictions here.

[0415] Similarly, the video to be encoded can be the original video to be encoded, or it can be a video region obtained by segmenting the video to be encoded; there are no restrictions here.

[0416] In an optional embodiment, taking the process shown in Figure 22 for the image to be encoded as an example, the method is the same when the object to be processed is the video to be encoded, and will not be described again here.

[0417] After performing wavelet transform on the image to be encoded, the encoder can obtain low-frequency subbands and high-frequency subbands.

[0418] The process of wavelet transform can be referred to the description of various embodiments of the encoder based on wavelet transform described above. The method of this application embodiment can be combined with the various embodiments of the encoder based on wavelet transform described above, and will not be repeated here.

[0419] In some embodiments, the encoder may obtain the current block based on the low-frequency sub-band obtained by wavelet transform of the image to be encoded, and perform the various encoding processes in Example A3 on the current block. In other embodiments, the encoder may also obtain the current block based on the high-frequency sub-band obtained by wavelet transform of the image to be encoded, and perform the various encoding processes in Example A3 on the current block.

[0420] The embodiments of this application do not limit the execution of the encoding method of the embodiments of this application to the current block in the high-frequency subband of the current frame or the current block in the low-frequency subband of the current frame.

[0421] Considering that the size of the low-frequency subband output by wavelet transform is only 1 / 4 of the image before wavelet transform (e.g., the image to be encoded), intra-frame prediction of the block data in the low-frequency subband can reduce the amount of data encoded compared to intra-frame prediction and encoding of the image to be encoded, thereby improving the efficiency of intra-frame prediction and encoding. Considering that the data distribution in the low-frequency subband is more uniform than that in the high-frequency subband output by wavelet transform, intra-frame prediction and encoding of the block data in the low-frequency subband using the method of this application embodiment can improve the accuracy of intra-frame prediction, thereby improving the encoding accuracy. Furthermore, the encoded block data of the low-frequency subband can be decoded and used for display; for example, the displayed image of the low-frequency subband can be a thumbnail of the image to be encoded (e.g., the original image to be encoded).

[0422] In some embodiments, the current block on the coding side can also be block data in the high-frequency subband obtained by wavelet transform, so as to perform intra-frame prediction and corresponding coding on the block data in the high-frequency subband. The process is similar to the process of performing intra-frame prediction and coding on the block data in the low-frequency subband, and will not be described in detail here.

[0423] In this embodiment, the current block is determined based on the low-frequency sub-band, and intra-frame prediction is performed on the current block to determine the predicted value of the current block. Since the data distribution of the low-frequency sub-band is relatively uniform, the thumbnail of the current frame can be determined based on the low-frequency sub-band. By using the low-frequency sub-band with relatively uniform data distribution for intra-frame prediction, the data of the determined reference block is closer to the data of the current block, and the obtained predicted value is more accurate.

[0424] In some embodiments, during the encoding process, the encoder determines the residual of the current block based on the predicted value and the actual value of the current block. During the decoding process, the decoder determines the reconstructed value of the current block based on the residual and the actual value of the current block. Therefore, the reconstructed value determined based on a more accurate predicted value is also more accurate, and the image obtained based on a more accurate reconstructed value is also more accurate, which can better reflect the information of the original image.

[0425] Before S102, as shown in Figure 22, the method further includes:

[0426] S122. Adjust the low-frequency subband to obtain the adjusted low-frequency subband.

[0427] In some embodiments, the encoder can perform an adjustment operation on the low-frequency subband based on the parameters of the adjustment operation to obtain the adjusted low-frequency subband.

[0428] The adjustment operation may include at least one of the precision adjustment and range adjustment shown in Figure 21.

[0429] In an optional embodiment, the parameters of the adjustment operation include at least one of a first adjustment parameter and a second adjustment parameter. The first adjustment parameter is used to adjust the data precision of the current block, and the second adjustment parameter is used to adjust the data range of the current block after wavelet transform.

[0430] It should be understood that S122 is not limited to being executed after S121. Specifically:

[0431] In some embodiments, the parameters of the adjustment operation include a first adjustment parameter. The encoder can perform precision adjustment on the current frame based on the first adjustment parameter before performing wavelet transform on the image to be encoded (hereinafter referred to as the "current frame") to obtain the precision-adjusted current frame.

[0432] The encoder can then perform wavelet transform on the current frame after precision adjustment to obtain the low-frequency subband, which is the low-frequency subband after precision adjustment.

[0433] Then, the range of the low-frequency subband after precision adjustment can be adjusted to obtain the low-frequency subband after the adjustment operation.

[0434] For example, as shown in Figure 22, the low-frequency subband obtained by S121 and S122 is the low-frequency subband after left shift (an example of precision adjustment) and increase of offset (an example of range adjustment).

[0435] In a specific embodiment, the encoder can shift the image to be encoded to the left based on the first adjustment parameter. The encoder performs wavelet transform on the image to be encoded after the left shift to obtain the low-frequency sub-band after the left shift. Then, an offset is added to the low-frequency sub-band after the left shift to obtain the low-frequency sub-band shown in S122.

[0436] The implementation process of S121 and S122 shown in Figure 22 is illustrated by an example, as shown in Figure 23a. Figure 23a is a schematic diagram of an encoding method provided by an embodiment of this application.

[0437] Please refer to Figure 23a(1). This raw data represents the data of each pixel in the image or video to be encoded. The data length of each of the three YUV components of each pixel is 10 bits. The range of the raw data x is: x∈[0,2]. 10 -1]. The process of adjusting the original data is illustrated by taking the pixels (or samples) in the current block of the image to be encoded as an example.

[0438] The objective of the adjustment operation in this embodiment is to adjust the range of x to: x∈[0, 2R), where R=2 12 Therefore, as shown in Figure 23a(1), the first adjustment parameter can be determined as: left shift by 2 bits.

[0439] The encoder processes the raw data (data length is 2). 10 The original data x has a range of [0, 2]. 10 After shifting the data left by 2 bits (-1), the range of the shifted data x becomes: x∈[0,2]. 12 -1];

[0440] Next, a wavelet transform can be performed on the left-shifted data x, so that the range of the data x after the wavelet transform is: Where R = 2 12 .

[0441] The encoder further truncates (Clip1) the wavelet-transformed data x, resulting in a range of data after Clip1.

[0442] Using Clip1, some data x after wavelet transform can be found to fall within the aforementioned range. Remove values ​​near the boundary so that the range of data x after Clip1 is:

[0443] The objective of the adjustment operation in this embodiment is to adjust the range of x to: x∈[0, 2R). To this end, the encoder can determine the second adjustment parameter for range adjustment as increasing. The range of x after range adjustment is: x∈[0,2).

[0444] The raw data shown in Figure 23a can be the data of each pixel in the current block (e.g., YUV), the data of each pixel in the image to be encoded (e.g., YUV), or the data of each pixel in a sub-image (e.g., YUV). There are no restrictions here.

[0445] In another specific example, please refer to Figure 23a(2). The process of left shifting and wavelet transforming the original data in Figure 23a(2) is the same as that in Figure 23a(1), and will not be repeated here. The difference from Figure 23a(1) is that an offset can be added to the wavelet transformed data first, and then Clip1 can be applied to the data with the added offset.

[0446] Similar to Figure 23a(1), the objective of the adjustment operation in this embodiment is to adjust the range of x to: x∈[0, 2R), where R=2 12 As shown in Figure 23a(2), the range of the data x after wavelet transform is: Then, the encoder adds an offset to the wavelet-transformed data x, where the second adjustment parameter for range adjustment determined by the encoder is to increase... The range of x after range adjustment is:

[0447] The encoder performs Clip1 on the range-adjusted data x, resulting in data with a range of x∈[0, 2R).

[0448] It should be understood that the objective of the adjustment operation in this embodiment is that the range of x after the adjustment operation is x∈[0, 2R). In other embodiments, the objective of the adjustment operation can also be other numerical ranges. For example, the range of x after the adjustment operation is x∈[2R, 4R), or x∈[2R, 5R), etc. The specific range can be flexibly set according to the needs, and is not limited here. In this way, when the objective changes, the first adjustment parameter and the second adjustment parameter involved in the adjustment operation can also change accordingly.

[0449] In some embodiments of this application, for different block data within the current frame, or block data within different frames, when the reference block corresponding to the current block is unavailable, the same preset reference data is used as its initial reference data. Then, following the same adjustment operation parameters and execution order, the same preset reference data corresponding to different block data or different frames is adjusted to obtain the same first data as the reference data for each block, used for intra-frame prediction. Thus, in scenarios where the reference block corresponding to any block to be encoded is unavailable, this application embodiment can use unified adjustment operation parameters to adjust the preset reference data, using the same first data as the data for the reference block corresponding to any of the blocks to be encoded, for intra-frame prediction, thereby reducing coding complexity.

[0450] In some embodiments, the same image includes different data blocks, the parameters of the corresponding adjustment operations are the same, the parameters of the adjustment operations corresponding to different images are also the same, and the parameters of the adjustment operations corresponding to different intra-frame prediction modes are also the same.

[0451] In some embodiments, the preset reference data remains globally consistent, and the preset reference data corresponding to different intra-frame prediction modes is the same. For example, the length of the original data x shown in Figure 23a is 10 bits, i.e., 2^32 bits. 10 For example, the range of the original data x is: x∈[0, 2]. 10 -1], then the encoder can determine the preset reference data as 2 9 .

[0452] In some embodiments, this application takes increasing the offset as an example. This application does not limit whether to increase or decrease the offset, as long as the data range of the current block after offset adjustment is a positive data range.

[0453] In some embodiments, the parameters of the adjustment operation are related to at least one of the following: the type of wavelet transform; and the data length of the block to be encoded before the wavelet transform and adjustment operation.

[0454] Taking Figure 23a(1) as an example, if the data length of each pixel in the block to be encoded is not 10 bits as shown in Figure 23a(1), then in order to meet the above objectives of the adjustment operation, the number of bits shifted to the left in the left shift operation may not be 2 bits, and the offset added by increasing the offset may also not be... Furthermore, if the type of wavelet transform shown in Figure 23a(1) changes, then the first and second adjustment parameters mentioned above may not be the left shift of 2 bits and the added offset shown in Figure 23a(1). Instead, the magnitudes of the first and second adjustment parameters are flexibly determined based on the type of wavelet transform.

[0455] In addition, the first adjustment parameter may include the adjustment amount and the adjustment type. For example, if the first adjustment parameter is left shift by 2 bits, then the adjustment type is left shift and the adjustment amount is 2 bits.

[0456] The second adjustment parameter may include the adjustment amount, adjustment type, and adjustment direction. For example, the second adjustment parameter is to increase the offset. The adjustment type is offset, the adjustment direction is increase, and the adjustment amount is... For example, the second adjustment parameter is to increase the offset. The adjustment type is offset, the adjustment direction is decrease, and the adjustment amount is...

[0457] Returning to Figure 22, as shown in Figure 22, the method also includes:

[0458] Optionally, S123. Divide the low-frequency subband into blocks to obtain the current block.

[0459] In an optional embodiment, the encoder divides the low-frequency subbands, which have undergone precision and range adjustments, into blocks to obtain the current block, which has also undergone precision and range adjustments.

[0460] In some embodiments, the low-frequency subband used for intra-frame prediction is a precision-adjusted low-frequency subband, and the encoder divides the precision-adjusted low-frequency subband into blocks to obtain the current block, which is precision-adjusted block data.

[0461] In other embodiments, the low-frequency sub-band is a range-adjusted low-frequency sub-band, and the encoder divides the range-adjusted low-frequency sub-band into blocks to obtain the current block, which is the range-adjusted block data.

[0462] It should be noted that the embodiments of this application do not limit the execution order of S122 and S123, that is, the embodiments of this application do not limit the execution order of the encoder's adjustment operation and the sub-block division process. For example, the decoder can first divide the low-frequency sub-band into blocks to obtain sub-blocks, and then adjust the sub-blocks to obtain the current block after the adjustment operation.

[0463] In other embodiments, the object of the adjustment operation can also be an image or a sub-image, with a similar principle, which will not be described in detail here.

[0464] Optionally, referring to Figure 22, the process may include S101a. Obtaining the actual value of the current block.

[0465] The actual value of the current block can be the block data obtained after the wavelet transform and adjustment operations described above.

[0466] For a detailed description of the implementation of S101a, please refer to Figure 21 for further details. It will not be repeated here.

[0467] As shown in Figure 22, the method further includes:

[0468] S101b, Obtain the first data.

[0469] Before S102, S101b and S121, S122, and S123 can be executed.

[0470] In some embodiments, the parameters of the above-described adjustment operation can be globally uniform. In other words, the parameters of the adjustment operation used for each current block are the same, regardless of whether the current block is different block data within the same image to be encoded, block data within different images to be encoded, different sub-images, or different sub-bands.

[0471] If the reference block corresponding to the current block is unavailable, the preset reference data is adjusted using the same adjustment operation parameters. In this way, S101b can be executed in parallel with the processes of S121 to S123 without S101b being executed after S123.

[0472] In this way, the data dimension of the first data is consistent with the data dimension of the current block obtained by S123.

[0473] The specific implementation of S101b can be referred to the specific implementation of S101b shown in Figure 21, and will not be repeated here.

[0474] S102. Based on the first data, perform intra-frame prediction on the current block after the above wavelet transform and adjustment operation to obtain the predicted value of the current block.

[0475] Thus, since the first data used as reference data for intra-frame prediction has undergone left shift and offset adjustment operations, and the current block has also undergone left shift and offset adjustment operations, the data dimensions of the first data and the current block used for intra-frame prediction are the same. Similarly, the predicted value of the current block output by intra-frame prediction is also consistent with the data dimensions of the first data and the current block. It can be understood that the predicted value has also undergone left shift and offset adjustment operations.

[0476] It should be noted that the embodiments of this application do not restrict the execution order between S101a and S102. That is, the embodiments of this application do not limit the execution order between the process of obtaining the actual value of the current block and the process of obtaining the predicted value of the current block.

[0477] S103. Encode the current block based on the predicted value to obtain a bitstream. In an optional embodiment, referring to Figure 22, the encoder calculates the residual of the current block based on the predicted value and the actual value of the current block, and then encodes the residual of the current block to obtain a bitstream.

[0478] In a specific embodiment, the encoder can encode the intra-prediction mode used by the current block and the residual of the current block to obtain the bitstream described above.

[0479] In optional embodiments, the reference block is determined based on the position of the current block and the intra-prediction mode of the current block. In some embodiments, the encoder may determine the reference block of the current block based on the position of the current block and the intra-prediction mode of the current block.

[0480] In specific embodiments, intra-frame prediction modes may include DC mode, vertical mode, horizontal mode, planar mode, and cross-component linear model (CCLM) mode, etc.

[0481] In an optional embodiment, if the reference block corresponding to the intra-prediction mode of the current block is unavailable, the reference data (i.e., the first data) for intra-prediction of the current block can be obtained by adjusting the preset reference data in the embodiment of this application.

[0482] In a specific embodiment, the encoder can determine the first reference block of the current block in the current frame based on the position of the current block. The encoder then determines the reference block (also called the second reference block) corresponding to the intra-prediction mode of the current block from the first reference block according to the intra-prediction mode of the current block. The second reference block is also called the reference block of the current block corresponding to the intra-prediction mode.

[0483] When a reference block corresponding to the prediction mode of the current block is available, the encoder uses the reconstructed value of this reference block (e.g., the second reference block mentioned above) to perform intra-frame prediction on the current block to obtain the predicted value of the current block. The reconstructed value of this reference block is also block data after wavelet transform and adjustment operations, and the data dimension of the second reference block is consistent with that of the current block. When a reference block corresponding to the prediction mode of the current block is not available, the encoder performs intra-frame prediction on the current block based on the first data to obtain the predicted value of the current block.

[0484] The following section, with reference to Figure 24, explains the scenario where the reference block corresponding to the current block is unavailable under different intra-frame prediction modes:

[0485] In Figure 24, the image to be encoded can be divided into 9 data blocks, arranged in the encoding order as block 1->block 2->block 3->block 4->block 5->block 6->block 7->block 8->block 9. Of course, this application does not limit the method of dividing the image into blocks or the number of blocks obtained.

[0486] In some embodiments, each block is 8x8 in size. In some embodiments, the block size can also be 8x4 or 4x4, and there is no limitation here.

[0487] Figure 24(1) shows that in a scene where the intra-prediction mode is horizontal, the reference block corresponding to the shaded block is unavailable.

[0488] In the horizontal mode shown by the arrow in Figure 24(1), the coded block to the left of the current block is taken as the reference block corresponding to the current block. If there is no coded block to the left of the current block in the current frame, the encoder determines that it cannot obtain the reference block corresponding to the current block, and thus obtains the first data as the reference data of the current block for intra-frame prediction.

[0489] For example, if the current block is located in the first column on the left side of the current frame as shown in Figure 24(1), such as when the current block is block 1, block 4 or block 7, the encoder determines that it cannot obtain the reference block corresponding to the current block. Thus, when the current block is block 1, block 4 or block 7, the reference block corresponding to the current block in the horizontal mode is unavailable, thereby obtaining the first data using the method of the embodiment of this application as reference data for intra-frame prediction of the current block.

[0490] In some embodiments, as shown in FIG24(1), when the current block is block 2, the encoder can use block 1 as the reference block corresponding to block 2 in horizontal mode. When the current block is block 3, the encoder can use block 2 as the reference block corresponding to block 3 in horizontal mode. When the current block is block 5, the encoder can use block 4 as the reference block corresponding to block 5 in horizontal mode. When the current block is block 6, the encoder can use block 5 as the reference block corresponding to block 6 in horizontal mode. When the current block is block 8, the encoder can use block 7 as the reference block corresponding to block 8 in horizontal mode. When the current block is block 9, the encoder can use block 8 as the reference block corresponding to block 9 in horizontal mode.

[0491] Figure 24(2) shows that in a scene where the intra-prediction mode is vertical, the reference block corresponding to the shaded block is unavailable.

[0492] In the vertical mode shown by the arrow in Figure 24(2), the coded block above the current block is used as the reference block corresponding to the current block. If there is no coded block above the current block in the current frame, the encoder determines that it cannot obtain the reference block corresponding to the current block, and thus obtains the first data as the reference data of the current block for intra-frame prediction.

[0493] For example, if the current block is located in the first row above the current frame as shown in FIG24(2), such as when the current block is block 1, block 2, or block 3, the encoder determines that it cannot obtain the reference block for the current block. Thus, when the current block is block 1, block 2, or block 3, the reference block corresponding to the current block in vertical mode is unavailable, thereby obtaining the first data using the method of the embodiments of this application as reference data for intra-frame prediction of the current block.

[0494] In some embodiments, as shown in FIG24(2), when the current block is block 4, the encoder can use block 1 as the reference block corresponding to block 4 in vertical mode. When the current block is block 5, the encoder can use block 2 as the reference block corresponding to block 5 in vertical mode. When the current block is block 6, the encoder can use block 3 as the reference block corresponding to block 6 in vertical mode. When the current block is block 7, the encoder can use block 4 as the reference block corresponding to block 7 in vertical mode. When the current block is block 8, the encoder can use block 5 as the reference block corresponding to block 8 in vertical mode. When the current block is block 9, the encoder can use block 6 as the reference block corresponding to block 9 in vertical mode.

[0495] Figure 24(3) shows that in a scenario where the intra-prediction mode is DC mode, the reference block corresponding to the shaded block is unavailable.

[0496] In DC mode, if at least one coded block is available, either the adjacent coded block above the current block or the adjacent coded block to the left of the current block, the reconstructed data of that coded block can be used as the reference block corresponding to the DC mode of the current block. If there is no reference block to the left or above the current block in the current frame, the encoder determines that it cannot obtain the reference block corresponding to the current block, and thus obtains the first data as the reference data of the current block for intra-frame prediction.

[0497] For example, if the current block is located in the first column on the left and the first row on the top of the current frame as shown in Figure 24(3), for example, if the current block is block 1, then there is no reference block for block 1 in the current frame, and the encoder determines that it cannot obtain the reference block for the current block.

[0498] In some embodiments, as shown in FIG24(3), when the current block is block 2, the encoder can use block 1 as the reference block corresponding to block 2 in DC mode. When the current block is block 3, the encoder can use block 2 as the reference block corresponding to block 3 in DC mode. When the current block is block 4, the encoder can use block 1 as the reference block corresponding to block 4 in DC mode. When the current block is block 5, the encoder can use at least one of block 2 and block 4 as the reference block corresponding to block 5 in DC mode. When the current block is block 6, the encoder can use at least one of block 3 and block 5 as the reference block corresponding to block 6 in DC mode. When the current block is block 7, the encoder can use block 4 as the reference block corresponding to block 7 in DC mode. When the current block is block 8, the encoder can use at least one of block 5 and block 7 as the reference block corresponding to block 8 in DC mode. When the current block is block 9, the encoder can use at least one of block 6 and block 8 as the reference block corresponding to block 9 in average mode.

[0499] Figure 24(4) shows that in a scene where the intra-prediction mode is planar, the reference block corresponding to the shaded block is unavailable.

[0500] In planar mode, the adjacent coded blocks above and to the left of the current block are used together as the reference block for the current block in planar mode. If there is no coded block on at least one side of the current block above or to the left of the current block in the current frame, the encoder determines that it cannot obtain the reference block corresponding to the current block, and thus obtains the first data as the reference data for the current block for intra-frame prediction.

[0501] For example, the encoder averages the reconstructed values ​​of the encoded blocks above and the encoded blocks to the left to obtain the reconstructed value of the reference block for the current block.

[0502] For example, if the current block is located in the first column on the left or the first row on the top of the current frame as shown in Figure 24(4), for example, if the current block is block 1, block 2, block 3, block 4, or block 7, then the encoder will determine that it cannot obtain the reference block corresponding to the current block in the planar mode.

[0503] With block 5 as the current reference block, the encoder can use blocks 2 and 4 as reference blocks for block 5 in planar mode.

[0504] If the current block is block 6, the encoder can use blocks 3 and 5 as reference blocks for block 6 in planar mode.

[0505] If the current block is block 8, the encoder can use blocks 5 and 7 as reference blocks for block 8 in planar mode.

[0506] If the current block is block 9, the encoder can use blocks 6 and 8 as reference blocks corresponding to block 9 in planar mode.

[0507] Figure 24(5) shows that in a scenario where the intra-prediction mode is CCLM, the reference block corresponding to the shaded block is unavailable.

[0508] In CCLM mode, the requirement for selecting the reference block corresponding to CCLM mode in the current block within the current frame is the same as the requirement for selecting the reference block in DC mode as shown in Figure 24(5).

[0509] In CCLM mode, if at least one coded block is available, either the adjacent coded block above the current block or the adjacent coded block to the left of the current block, the reconstructed data of that coded block can be used as the reference block for the DC mode of the current block. If there is no reference block to the left or above the current block in the current frame, the encoder determines that it cannot obtain the reference block corresponding to the current block, and thus obtains the first data as the reference data for the current block for intra-frame prediction.

[0510] For example, if the current block is located in the first column on the left and the first row on the top of the current frame as shown in Figure 24(5), for example, if the current block is block 1, the encoder cannot obtain the reference blocks to the left and top of block 1 in the current frame, so that the encoder determines that it cannot obtain the reference block corresponding to the current block in CCLM mode.

[0511] When the current block is block 2, the encoder can use block 1 as the reference block for block 2 in CCLM mode. When the current block is block 3, the encoder can use block 2 as the reference block for block 3 in CCLM mode. When the current block is block 4, the encoder can use block 1 as the reference block for block 4 in CCLM mode. When the current block is block 5, the encoder can use both blocks 2 and 4 as reference blocks for block 5 in CCLM mode. When the current block is block 6, the encoder can use at least one of blocks 3 and 5 as the reference block for block 6 in CCLM mode. When the current block is block 7, the encoder can use block 4 as the reference block for block 7 in CCLM mode. When the current block is block 8, the encoder can use at least one of blocks 5 and 7 as the reference block for block 8 in CCLM mode. When the current block is block 9, the encoder can use at least one of blocks 6 and 8 as the reference block for block 9 in CCLM mode.

[0512] Example B3

[0513] Corresponding to Example A3 above, Example B3 of this application describes the implementation process of the decoding methods of various embodiments of this application.

[0514] In conjunction with the encoding method of any of the above embodiments, this application also provides a decoding method, which can be used in conjunction with the above-mentioned encoding method with wavelet transform (also known as forward wavelet transform) (e.g., the encoding method involved in any of the embodiments in Figures 6 to 19). In addition, the decoding method can also be combined with the above-mentioned decoding method with inverse wavelet transform (e.g., the decoding method involved in any of the embodiments in Figures 6 to 19).

[0515] Corresponding to the encoding method in Example A3 above, this application embodiment also provides a decoding method.

[0516] Corresponding to the encoding method shown in Figure 21 above, Figures 25 and 26 respectively exemplarily illustrate flowcharts of two decoding methods according to embodiments of this application. The same steps in Figures 25 and 26 represent the same process, and will not be repeated.

[0517] As shown in Figure 25, the method flow may include, but is not limited to, the following steps:

[0518] S501a. Obtain the bitstream of the image to be decoded (also known as the current frame).

[0519] The image to be decoded may include the block to be decoded (also known as the current block).

[0520] In optional embodiments, the image to be decoded can be the original image, a sub-image after dividing the original image, or an encoded image of a low-frequency or high-frequency image obtained by performing wavelet transform on the original image or sub-image, etc. For details, please refer to the description of the image to be decoded above, which will not be repeated here. For example, the image to be decoded can be described as the current frame.

[0521] In an optional embodiment, the current block undergoes wavelet transform and adjustment operations during encoding. The specific process of wavelet transform and adjustment operations on the current block can be referred to in Example 3A, and will not be repeated here.

[0522] In an optional embodiment, the current block is the block data in the wavelet coefficients of the low-frequency subband obtained after wavelet transform during the encoding of the current frame.

[0523] In some embodiments, after the decoder receives the bitstream of the current frame, it obtains the position of the current block from the bitstream of the current frame.

[0524] Alternatively, in some embodiments, the blocks in the current frame are decoded sequentially. For example, as shown in FIG24, blocks 1 to 9 in the current frame are decoded in the above-described encoding order. In this way, the decoder can determine the position of the current block in the current frame according to the decoding order. For example, the decoder decodes in the order of block 1->block 2->block 3->block 4->block 5->block 6->block 7>block 8->block 9.

[0525] In an optional embodiment, as shown in FIG26, the decoder also decodes the intra-prediction mode used by the current block and the residual of the current block from the bitstream of the current frame.

[0526] Referring to the description in Example A3 above, it can be seen that the residual of the current block in the bitstream is the residual between the actual value of the current block and the predicted value of the current block. Furthermore, the actual value and the predicted value (refer to Figure 22) are both in the same data dimension after the adjustment operation (e.g., after left shift and increase of offset). Thus, the residual is also in this data dimension. As shown in Figure 25, in one example, the bitstream can be described as the residual in the bitstream also being adjusted by left shift and increase of offset.

[0527] S501b. Obtain the first data.

[0528] In some embodiments, if the reference block corresponding to the current block cannot be obtained, the decoder may obtain the first data.

[0529] In some embodiments, the reference block is the reference block corresponding to the intra-prediction mode of the current block; however, the decoded block in the image to be decoded is different from the reference block.

[0530] For various scenarios where the reference block corresponding to the current block cannot be obtained (hereinafter referred to as the reference block of the current block being unavailable), please refer to the corresponding description in Example A3, which will not be repeated here.

[0531] For example, refer to the above description of the unavailability of the reference block for the current block under various intra-prediction modes shown in Figure 24.

[0532] In an optional embodiment, the first data is obtained by adjusting the second data based on the parameters of the adjustment operation, and the second data is preset reference data. In a specific embodiment, the decoder can adjust the preset reference data based on the parameters of the adjustment operation to obtain the first data.

[0533] In an optional embodiment, the parameters of the adjustment operation may include at least one of a first adjustment parameter and a second adjustment parameter.

[0534] In scenarios where the reference block for the current block is unavailable, preset reference data can be obtained as the reference block for the intra-prediction mode of the current block. However, since the current block undergoes wavelet transform and the aforementioned adjustment operations during intra-prediction, to ensure that the reference data for the current block is in the same dimension as the current block, the preset reference data can be adjusted using the parameters of the aforementioned adjustment operations (the parameters used when the current block is adjusted), thereby obtaining first data. This first data, after the adjustment operation, can be used as the reference block for the current block in intra-prediction. Thus, when performing intra-prediction on the current block, the data dimension of the first data serving as the reference block is the same as the data dimension of the predicted current block, thereby improving the accuracy of the intra-prediction prediction data and consequently improving the decoding accuracy.

[0535] In the embodiment shown in Figure 25, the adjustment operation includes precision adjustment and range adjustment as an example. In other embodiments, the adjustment operation may include either precision adjustment or range adjustment. However, the adjustment operation performed on the preset reference data is the same as the adjustment operation performed on the current block during encoding.

[0536] In some embodiments, when performing an adjustment operation on preset reference data, the order in which the adjustment parameters (at least one of the first adjustment parameter and the second adjustment parameter) are used is consistent with the order in which the adjustment parameters are used when the current block is performing the adjustment operation.

[0537] This ensures that the first data obtained after adjusting the preset reference data, when used as reference data for intra-frame prediction of the current block, is in the same dimension as the first data, thus ensuring the accuracy of intra-frame prediction.

[0538] In the embodiment shown in Figure 25, the adjustment operations performed on the preset reference data sequentially include precision adjustment and range adjustment. Thus, the first data is obtained by adjusting the preset reference data sequentially according to the first adjustment parameter and the second adjustment parameter.

[0539] In some embodiments, the preset reference data may be subjected to precision adjustment (e.g., precision adjustment according to a first adjustment parameter) and range adjustment (e.g., range adjustment based on a second adjustment parameter) in sequence to obtain the first data.

[0540] When the preset reference data undergoes the above adjustment operations, the precision adjustment and the range adjustment are performed sequentially, so that the order of precision adjustment and range adjustment of the preset reference data adjustment operations is consistent with the order of precision adjustment and range adjustment of the current block during encoding.

[0541] In this embodiment, the preset reference data is first adjusted for precision, and then adjusted for range. Precision adjustment improves the precision of the adjusted data, allowing the adjusted preset reference data to retain higher precision for intra-frame prediction and decoding, thereby improving the accuracy of the intra-frame prediction data. Performing range adjustment after precision adjustment ensures that the current block and the first data used for intra-frame prediction are of the same dimension.

[0542] In some embodiments, the first data is obtained by shifting the preset reference data to the left according to the first adjustment parameter, and by adding an offset to the second data after the left shift according to the second adjustment parameter.

[0543] For example, in binary data, shifting left by 1 bit is equivalent to multiplying by 2, for instance, if the default reference data before the left shift is 2. 9 For example, if the first adjustment parameter is to shift left by 2 bits, then the preset reference data after the left shift is 2. 11 This improves the accuracy of the preset reference data. Then, for example, the second adjustment parameter is increased by 2. 11 Then the preset reference data 2 after shifting to the left can be used. 11 Increase offset (here it is 2) 11 ), to obtain the first data (specifically 2) 12 ).

[0544] The number of bits shifted left on the preset reference data is the same as the number of bits shifted left during the encoding of the current block (e.g., the process in Example A3 above) (e.g., a 2-bit left shift as shown in Figure 23a). Similarly, the specific offset by which the preset reference data is incremented is also the same as the specific offset by which the current block is incremented during encoding (e.g., the process in Example A3 above) (e.g., as shown in Figure 23a). ).

[0545] In some embodiments, the second adjustment parameter may be specifically used to adjust the data range of the preset reference data to a positive data range.

[0546] For example, the preset reference data range is Where R is 2 12 The second adjustment parameter can then be an increase in the specific offset. That is, increase the offset to 2. 11 To increase the data range The preset reference data, after being adjusted by the second adjustment parameter, has a data range of [0, 2R]. Thus, after the preset reference data is adjusted according to the second adjustment parameter, the adjusted data range is [0, 2R], which is a data range consisting of positive numbers.

[0547] In some embodiments, the data range of the preset reference data is a negative data range, such as the one described above. A negative data range indicates that the minimum value in the data range is negative. Therefore, when representing the preset reference data, a sign bit is needed to represent the negative value, resulting in a longer bit width for the preset reference data. This means that when the preset reference data is used for intra-frame prediction (or inter-frame prediction), it occupies a longer bit width. To address this, the decoder in this embodiment can adjust the data range of the preset reference data from a negative data range to a positive data range. This positive data range indicates that the minimum value in the data range is zero or a positive number. Thus, when the data after range adjustment by the second adjustment parameter is represented (e.g., in binary data), only the data value needs to be represented, without occupying at least one bit (e.g., a sign bit) to represent that the data is negative. This reduces the bit width of the preset reference data used for intra-frame prediction (or inter-frame prediction), improving prediction efficiency and coding efficiency.

[0548] The above embodiment uses 0 as an example to illustrate the concept. In other embodiments, the minimum value in the positive number range can also be a number greater than 0 (e.g., 2). 11 -1). In this way, the second adjustment parameter can be changed, and is not limited to the data range used to adjust the preset reference data to the minimum value of 0.

[0549] Furthermore, in the above embodiments, the data range of the preset reference data is as described above. For example, if the goal of range adjustment is to make the minimum value of the adjusted data range 0, then the second adjustment parameter is to increase... That is, the offset is In some embodiments, the data range of the preset reference data can be a data range greater than 0 (e.g., For example, if the goal of range adjustment is to make the minimum value of the adjusted data range 0, then the second adjustment parameter is to subtract... That is, offset is The range of data after range adjustment is

[0550] Of course, if the goal of range adjustment is that the minimum value of the adjusted data range (i.e., the left boundary value of the data range) is a value greater than 0, the second adjustment parameter can also be changed based on this goal to meet the adjustment goal, which will not be elaborated here.

[0551] Thus, when the second adjustment parameter is to increase the offset, the offset can be either positive or negative, as long as the data after increasing the offset meets the target of the adjustment operation.

[0552] In some embodiments, the parameters of the adjustment operation performed on the preset reference data are related to at least one of the following: the type of wavelet transform; the data length of the block to be decoded (i.e., the current block) before the wavelet transform and adjustment operation (e.g., the length of the original data shown in FIG23a is 10 bits).

[0553] In addition, the first adjustment parameter may include the adjustment amount and the adjustment type. For example, if the first adjustment parameter is left shift by 2 bits, then the adjustment type is left shift and the adjustment amount is 2 bits.

[0554] The second adjustment parameter may include the adjustment amount, adjustment type, and adjustment direction. For example, the second adjustment parameter is to increase the offset. The adjustment type is offset, the adjustment direction is increase, and the adjustment amount is... For example, the second adjustment parameter is to increase the offset. The adjustment type is offset, the adjustment direction is decrease, and the adjustment amount is...

[0555] In optional embodiments, the reference block is determined based on the position of the current block and the intra-prediction mode of the current block. In some embodiments, the decoder may determine the reference block of the current block based on the position of the current block and the intra-prediction mode of the current block.

[0556] In specific embodiments, intra-frame prediction modes may include DC mode, vertical mode, horizontal mode, planar mode, and cross-component linear model (CCLM) mode, etc.

[0557] In an optional embodiment, if the reference block corresponding to the intra-prediction mode of the current block is unavailable, the reference data (i.e., the first data) for intra-prediction of the current block can be obtained by adjusting the preset reference data in the embodiment of this application.

[0558] In a specific embodiment, the decoder can determine the first reference block of the current block in the current frame based on the position of the current block. Then, the decoder determines the reference block (also called the second reference block) corresponding to the intra-prediction mode of the current block from the first reference block according to the intra-prediction mode of the current block. The second reference block is also called the reference block of the current block corresponding to the intra-prediction mode.

[0559] When the reference block corresponding to the prediction mode of the current block can be obtained, the decoder uses the reconstructed value of the reference block to perform intra-frame prediction on the current block to obtain the prediction value of the current block. The reconstructed value of the reference block is also block data after wavelet transform and adjustment operations. The data dimension of the second reference block is consistent with the data dimension of the current block.

[0560] In some embodiments, if a reference block corresponding to the prediction mode of the current block cannot be obtained, the decoder performs intra-frame prediction on the current block based on the first data to obtain the prediction value of the current block.

[0561] S502. Based on the first data, perform intra-frame prediction on the current block to obtain the predicted value of the current block.

[0562] In an optional embodiment, as shown in FIG26, the decoder can decode from the bitstream to obtain a syntax element indicating the intra-prediction mode adopted by the current block, and perform intra-prediction on the current block based on the first data according to the intra-prediction mode adopted by the current block indicated by the syntax element, so as to obtain the prediction value of the current block.

[0563] In some embodiments, the intra-prediction mode (also referred to as the first intra-prediction mode) on the chroma component can be one of the following: vertical mode, horizontal mode, DC mode, and CCLM mode.

[0564] In some embodiments, the intra-prediction mode (also referred to as the second intra-prediction mode) on the luminance component can be one of the following: vertical mode, horizontal mode, DC mode, and planar mode.

[0565] Because the first data for intra-frame prediction of the current block has undergone left shift and offset adjustment operations, the predicted value of the current block obtained by intra-frame prediction is also equivalent to having undergone left shift and offset processing, making the predicted value the same data dimension as the first data.

[0566] S503. Based on the predicted value of the current block, decode the above bitstream to obtain the reconstructed value of the current block.

[0567] In an optional embodiment, the decoder determines the reconstructed value of the current block based on the predicted value and the residual of the current block. For example, the decoder determines the reconstructed value of the current block as the sum of the predicted value and the residual of the current block.

[0568] As described in Example A3 above, the residual is equivalent to being processed by left shift and increasing offset, and the predicted value of the current block is also equivalent to being processed by left shift and increasing offset.

[0569] In some embodiments, the reconstructed value of the current block obtained in S503 (represented by reconstructed value 1) may be of the same data dimension as the first data and the predicted value of the current block, ensuring accurate reconstruction of the current block. Therefore, when the reconstructed current block is used as a reference block for intra-frame prediction of subsequent blocks, the reconstructed value 1 of the current block can be cached for use as a reference block in the intra-frame prediction mode of the aforementioned subsequent blocks.

[0570] In some other embodiments, the reconstruction value of the current block obtained in S503 (represented by reconstruction value 2) may be the reconstruction value obtained after performing an inverse adjustment operation on the reconstruction value 1.

[0571] The inverse adjustment operation is the reverse of the order of the adjustment operations described above. For example, if the adjustment operations are left shift by 2 bits and offset increment, the inverse adjustment operation is offset decrement and right shift by 2 bits to restore the reconstructed value of the current block before the adjustment operation (represented by reconstructed value 2).

[0572] In some embodiments, when the current block decoded by S503 is used as a reference block for inter-frame prediction of subsequent blocks, or when the decoded current block is used for display, the reconstruction value 2 of the current block can be obtained by performing an inverse adjustment operation on the reconstruction value 1 of the current block obtained by S503, as shown in S504 of FIG26.

[0573] Regarding the timing of performing the inverse adjustment operation on the reconstructed value 1, it can be performed after the current block and the reconstructed blocks within the current frame have been reconstructed into sub-images or into images to be displayed, and then the inverse adjustment operation is performed on the sub-images or the images to be displayed. Alternatively, the inverse adjustment operation on the reconstructed value 1 of the current block can be performed before the current block is reconstructed into a reconstructed sub-image or before it is reconstructed into an image; there is no restriction here.

[0574] The aforementioned reconstruction value 2 is also called the reconstruction value of the current block without the above adjustment operation (or after the reverse adjustment operation).

[0575] The reverse adjustment operation is the opposite of the adjustment sequence of the above adjustment operations. For example, if the order of the adjustment operations is precision adjustment first and then range adjustment, then the reverse adjustment operation is range adjustment first and then precision adjustment.

[0576] The adjustment parameter used in the inverse adjustment operation is the inverse of the adjustment parameter of the above adjustment operation. For example, if the adjustment parameter of the adjustment operation is left shift by 2 bits, then the corresponding inverse parameter is right shift by 2 bits. For example, if the adjustment parameter is to increase the offset (e.g.) The corresponding inverse parameter is to reduce the offset (e.g., ).

[0577] In some embodiments, the first data is obtained by adjusting the preset reference data in the order of left shift by 2 bits and increasing the offset, and the reconstruction value 2 of the current block without adjustment is obtained by adjusting the reconstruction value 1 of the current block in the order of decreasing the offset and right shift by 2 bits.

[0578] Corresponding to Figure 23a above, Figure 23b is a schematic diagram of a decoding method provided by an embodiment of this application. The current block on the encoding side has been sequentially shifted left by 2 bits and an offset has been increased. The inverse adjustment operation performed on the decoder side for the reconstructed value 1 is, in sequence, to reduce the offset. And right-shift by 2 bits.

[0579] As a concrete example, please refer to Figure 23b. The reconstructed value 1 represents the reconstructed value 1 of each pixel in the image or video to be decoded. The data length of each of the three YUV components of each pixel is 13 bits after adjustment. The range of the reconstructed value 1 (represented by x') is: x′∈[0, 2R). The adjustment process of the reconstructed value 1 is illustrated by taking the pixel (or sample) in the current block of the image to be decoded as an example.

[0580] The decoder reduces the offset of the reconstructed value 1 (this offset is the same as the offset of the range adjustment traversed by the aforementioned preset reference data), specifically by reducing... The range of the reconstructed value 1 for the current block after reducing the offset is:

[0581] Please refer to Figure 23a(1), after Clip1. After reducing offset operations Since their ranges are consistent, the decoding side does not need to perform a Clip1 operation again. Then, as shown in Figure 23b, the decoder can reduce... The reconstructed value 1 is then right-shifted by 2 bits (the number of bits shifted is the same as the number of bits adjusted for precision in the aforementioned preset reference data) to obtain the range of the reconstructed value 1 of the current block after the right shift.

[0582] Optionally, in order to enable the current block to be used as a reference block for display or for inter-frame prediction of subsequent blocks, as shown in Figure 23b, the reconstructed value after being right-shifted by 2 bits can be clipped, so that the reconstructed value 2 of the current block obtained after clipping is in the range x′∈[0,2]. 10 -1], so that the length of the reconstructed value 2 is 10 bits, which is convenient for display and inter-frame prediction.

[0583] Regarding the data ranges captured by Clip2 and Clip1, this application does not limit them to being the same; they are independent of each other and serve different purposes. Clip1 is to satisfy the adjustment operation objectives described on the encoding side. Clip2, on the other hand, is to enable the reconstructed value 2 to be used for display and inter-frame prediction.

[0584] Based on the same concept as the above method, as shown in FIG27a, this application embodiment also provides a decoding device 1000, which includes: an acquisition module 1001, used to acquire the bitstream of an image to be decoded, the image to be decoded including a block to be decoded; the acquisition module 1001 is further used to acquire first data when a reference block corresponding to the block to be decoded cannot be acquired, the first data being obtained by adjusting second data based on the parameters of an adjustment operation, the second data being preset reference data, the parameters of the adjustment operation including at least one of a first adjustment parameter and a second adjustment parameter, the first adjustment parameter being used to adjust the data precision of the second data, and the second adjustment parameter being used to adjust the data range of the second data; a prediction module 1002, used to perform intra-frame prediction on the block to be decoded based on the first data to obtain the prediction data of the block to be decoded; and a decoding module 1003, used to decode the bitstream based on the prediction data to obtain the reconstructed data of the block to be decoded.

[0585] Based on the same concept as the above method, as shown in Figure 27b, this application embodiment also provides an encoding device 2000, which includes: an acquisition module 2001, used to acquire first data when a reference block corresponding to the block to be encoded in the image to be encoded cannot be acquired, the first data being obtained by adjusting second data based on the parameters of an adjustment operation, the second data being preset reference data, the parameters of the adjustment operation including at least one of a first adjustment parameter and a second adjustment parameter, the first adjustment parameter being used to adjust the data precision of the second data, and the second adjustment parameter being used to adjust the data range of the second data; a prediction module 2002, used to perform intra-frame prediction on the block to be encoded based on the first data to obtain the prediction data of the block to be encoded; and an encoding module 2003, used to encode the block to be encoded based on the prediction data to obtain a bitstream.

[0586] The prediction module 1002 of the aforementioned decoding device can be applied to the intra-frame prediction process at the decoding end. Specifically, at the decoding end, the prediction module 1002 can be applied to the intra-frame prediction unit or prediction unit of the aforementioned decoder.

[0587] The prediction module 2002 of the aforementioned encoding apparatus can be applied to the intra-frame prediction process at the encoding end. Specifically, at the encoding end, the prediction module 2002 can be applied to the intra-frame prediction unit or prediction unit of the aforementioned encoder.

[0588] The specific implementation process of the encoding device and the decoding device can be referred to the relevant descriptions of the encoding method and decoding method embodiments, and will not be repeated here for the sake of brevity.

[0589] The steps of the methods or algorithms described in conjunction with the embodiments of this application can be implemented in hardware or by a processor executing software instructions. The software instructions can consist of corresponding software modules, which can be stored in random access memory (RAM), flash memory, read-only memory (ROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), registers, hard disks, portable hard disks, CD-ROMs, or any other form of storage medium well known in the art. An exemplary storage medium is coupled to a processor, enabling the processor to read information from and write information to the storage medium. Of course, the storage medium can also be a component of the processor. The processor and the storage medium can reside in an ASIC.

[0590] Those skilled in the art will recognize that the functions described in the embodiments of this application in one or more of the above examples can be implemented using hardware, software, firmware, or any combination thereof. When implemented using software, these functions can be stored in a computer-readable medium or transmitted as one or more instructions or code on a computer-readable medium. Computer-readable media include computer storage media and communication media, wherein communication media include any medium that facilitates the transfer of a computer program from one place to another. Storage media can be any available medium that can be accessed by a general-purpose or special-purpose computer.

[0591] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the protection scope of the technical solutions of the embodiments of this application.

Claims

1. A decoding method, characterized in that, The method includes: Obtain the bitstream of the image to be decoded, wherein the image to be decoded includes blocks to be decoded; When the reference block corresponding to the block to be decoded is unavailable, first data is obtained. The first data is obtained by adjusting the second data based on the parameters of the adjustment operation. The second data is preset reference data. The parameters of the adjustment operation include at least one of a first adjustment parameter and a second adjustment parameter. The first adjustment parameter is used to adjust the data precision of the second data, and the second adjustment parameter is used to adjust the data range of the second data. Based on the first data, intra-frame prediction is performed on the block to be decoded to obtain the prediction data of the block to be decoded; Based on the predicted data, the bitstream is decoded to obtain the reconstructed data of the block to be decoded.

2. The method according to claim 1, characterized in that, The image to be decoded is a low-frequency LL subband image.

3. The method according to claim 2, characterized in that, The block to be decoded is the block data in the wavelet coefficients of the low-frequency LL subband.

4. The method according to claim 1 or 2, characterized in that, If the reference block corresponding to the block to be decoded is not decoded or the reference block corresponding to the block to be decoded does not exist, then the reference block corresponding to the block to be decoded is unavailable.

5. The method according to any one of claims 1 to 4, characterized in that, The adjustment operation of the second data based on the first adjustment parameter includes: The second data is shifted to the left based on the first adjustment parameter.

6. The method according to claims 1 to 5, characterized in that, The adjustment operation of the second data based on the second adjustment parameter includes: The offset is added to the second data based on the second adjustment parameter.

7. The method according to any one of claims 1 to 6, characterized in that, The second adjustment parameter is specifically used to adjust the data range of the second data to a positive data range.

8. The method according to any one of claims 1 to 7, characterized in that, The adjustment of the second data based on the adjustment parameters includes: The second data is adjusted based on the first adjustment parameter to obtain the adjusted data; The adjusted data is adjusted based on the second adjustment parameter to obtain the first data.

9. The method according to any one of claims 1 to 8, characterized in that, The method further includes: The parameters of the adjustment operation are obtained from the bitstream.

10. The method according to any one of claims 1 to 9, characterized in that, The reference block is determined based on the position of the block to be decoded and the intra-frame prediction mode of the block to be decoded.

11. An encoding method, characterized in that, The method includes: When the reference block corresponding to the block to be encoded in the image to be encoded is unavailable, first data is obtained. The first data is obtained by adjusting the second data based on the parameters of the adjustment operation. The second data is a preset reference data. The parameters of the adjustment operation include at least one of a first adjustment parameter and a second adjustment parameter. The first adjustment parameter is used to adjust the data precision of the second data, and the second adjustment parameter is used to adjust the data range of the second data. Based on the first data, intra-frame prediction is performed on the block to be encoded to obtain the prediction data of the block to be encoded. Based on the predicted data, the block to be encoded is encoded to obtain a bitstream.

12. The method according to claim 11, characterized in that, The image to be encoded is a low-frequency subband image.

13. The method according to claim 11 or 12, characterized in that, The block to be encoded is obtained after wavelet transform and the adjustment operation.

14. The method according to any one of claims 11 to 13, characterized in that, If the reference block corresponding to the block to be encoded is not encoded or the reference block corresponding to the block to be encoded does not exist, then the reference block corresponding to the block to be encoded is unavailable.

15. The method according to any one of claims 11 to 14, characterized in that, The adjustment operation of the second data based on the first adjustment parameter includes: The second data is shifted to the left based on the first adjustment parameter.

16. The method according to any one of claims 11 to 15, characterized in that, The adjustment operation of the second data based on the second adjustment parameter includes: The offset is added to the second data based on the second adjustment parameter.

17. The method according to any one of claims 11 to 16, characterized in that, The adjustment of the second data based on the adjustment parameters includes: The second data is adjusted based on the first adjustment parameter to obtain the adjusted data; The adjusted data is adjusted based on the second adjustment parameter to obtain the first data.

18. The method according to any one of claims 11 to 17, further comprising: The parameters of the adjustment operation are encoded into the bitstream.

19. The method according to any one of claims 11 to 18, characterized in that, The reference block is determined based on the position of the block to be encoded and the intra-prediction mode of the block to be encoded.

20. An encoder, characterized in that, include: A memory and a processor, wherein the memory is coupled to the processor; The memory stores program instructions that, when executed by the processor, cause the processor to perform the steps of the method as claimed in any one of claims 11 to 19.

21. A decoder, characterized in that, include: A memory and a processor, wherein the memory is coupled to the processor; The memory stores program instructions that, when executed by the processor, cause the processor to perform the steps of the method as claimed in any one of claims 1 to 10.

22. An encoder, characterized in that, include: A processing circuit that implements the steps of the method as claimed in any one of claims 11 to 19.

23. A decoder, characterized in that, include: A processing circuit that implements the steps of the method as claimed in any one of claims 1 to 10.

24. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program that, when executed on a computer or processor, causes the computer or processor to perform the method as described in any one of claims 1 to 10, or causes the computer or processor to perform the method as described in any one of claims 11 to 19.

25. A computer program product, characterized in that, The computer program product includes computer instructions that, when executed by a computer or processor, cause the steps of the method as described in any one of claims 1 to 10 to be performed, or cause the steps of the method as described in any one of claims 11 to 19 to be performed.

26. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a bitstream generated according to the method described in any one of claims 11 to 19.

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