CN112235568B

CN112235568B - Image encoding method, decoding method, device and storage medium

Info

Publication number: CN112235568B
Application number: CN201910635627.7A
Authority: CN
Inventors: 林永兵; 伍勇
Original assignee: Huawei Technologies Co Ltd
Current assignee: Huawei Technologies Co Ltd
Priority date: 2019-07-15
Filing date: 2019-07-15
Publication date: 2024-03-26
Anticipated expiration: 2039-07-15
Also published as: CN112235568A; WO2021008535A1

Abstract

The application provides an image encoding method, a decoding method, an apparatus and a storage medium. The image decoding method includes: acquiring a code stream, and acquiring a residual block of an image block and a prediction block of the image block according to the code stream; obtaining an image block according to the residual block of the image block and the prediction block of the image block; and (5) carrying out the processing of the decoded image block to obtain a final image block. The value of the N placeholders of the pixel value of the final image block is opposite to the value of the N placeholders of the pixel value of the image block, or the value of the N placeholders of the pixel value of the final image block is obtained by performing exclusive OR processing on each placeholder of the N placeholders of the pixel value of the image block and each placeholder adjacent to the higher place. The method and the device can compress the image blocks, so that the storage space occupied by the code stream is reduced.

Description

Image encoding method, decoding method, device and storage medium

Technical Field

The present application relates to the field of image encoding and decoding technologies, and more particularly, to an image encoding method, decoding method, apparatus, and storage medium.

Background

The laser detection and ranging system (light laser detection and ranging, liDAR) is a radar system that uses a laser as a radiation source, which may be referred to simply as a LiDAR. The laser radar is a product of combining a laser technology and a radar technology, and has the characteristics of high detection precision, large measurement range, non-contact, 3D measurement, 360-degree measurement and the like. The laser radar is commonly used for high-precision map construction, high-precision positioning, target detection, 3D scene rendering and the like.

The amount of 3D point cloud data generated by lidar measurement is enormous, which presents a great challenge for point cloud data storage and transmission. In order to reduce the storage amount of the point cloud data, the 3D point cloud data is generally converted into 2D point cloud data as a positioning layer. However, the bitmap layer still covers a large geographic area, the data volume is still large, and the code stream obtained by encoding the image in the point cloud data still occupies a large storage overhead.

Disclosure of Invention

The application provides an image encoding method, an image decoding device and a storage medium, so as to reduce the storage overhead of a code stream.

In a first aspect, there is provided an image decoding method, the method comprising: acquiring a code stream; acquiring a residual block of an image block and a prediction block of the image block according to the code stream; obtaining an image block according to the residual block of the image block and the prediction block of the image block; and processing the image block to obtain a processed image block.

The pixel value of the image block is represented by M bits, the value of each bit is 0 or 1, and M is an integer greater than 1.

The value of the ith bit in the N bits of the pixel value of the image block is opposite to the value of the ith bit in the N bits of the pixel value of the processed image block, and the N bits of the pixel value of the image block are positioned at the same position as the N bits of the pixel value of the processed image block.

N bits of the pixel value of the image block are located after and adjacent to the first bit of the pixel value of the image block, wherein the first bit is a bit with a value of 1 and the highest bit number in the pixel value of the image block, i and N are positive integers, i is less than or equal to N, and N is less than M.

In this embodiment of the present application, the encoding end performs the inversion processing on the pixel value of the image block, so that the data size of the image block can be reduced when the pixel value of the image block includes a continuous placeholder, so that the code stream generated by encoding occupies less storage space, and the decoding end performs the inversion processing on the image block obtained by decoding, so that the image block processed by the encoding end (the inversion processing) can be restored, and a final image block is obtained.

With reference to the first aspect, in certain implementation manners of the first aspect, acquiring, according to a code stream, a residual block of an image block includes: and performing inverse transformation, inverse quantization and entropy decoding on the code stream to obtain a residual block.

The decoding process corresponds to lossy encoding of the image in such a way that the encoded code stream occupies as little memory space as possible.

With reference to the first aspect, in certain implementation manners of the first aspect, acquiring, according to a code stream, a residual block of an image block includes: and performing entropy decoding treatment on the code stream to obtain a residual block.

The decoding mode for only performing entropy decoding corresponds to lossless encoding, and the encoding mode can avoid image distortion as far as possible and ensure the final display effect of the image.

With reference to the first aspect, in some implementations of the first aspect, the code stream is encoded with a positioning bit map layer.

With reference to the first aspect, in certain implementations of the first aspect, locating pixel values of the map layer includes rasterized elevation data.

The pixel value of the positioning map layer contains M bits, each bit representing an occupied bit of each grid. Because the pixel value of the positioning image layer contains the rasterized elevation data, and the probability of the character 11 appearing in the high order in the elevation data is relatively high, the data volume of the pixel value of the positioning image layer can be reduced by processing the pixel value of the positioning image layer containing the elevation data, and the storage space occupied by the finally obtained code stream is further reduced.

With reference to the first aspect, in certain implementations of the first aspect, the value of M is any one of 8, 10, and 12.

In a second aspect, there is provided an image decoding method, the method comprising: acquiring a code stream; according to the code stream, obtaining a residual block of an image block and a prediction block of the image block, wherein the pixel value of the residual block is represented by M bits, the value of each bit is 0 or 1, and M is an integer greater than 1; processing the residual block to obtain a processed residual block;

Wherein the value of the ith bit in the N bits of the pixel value of the residual block is opposite to the value of the ith bit in the N bits of the pixel value of the processed residual block, the N bits of the pixel value of the residual block are positioned at the same position as the N bits of the pixel value of the processed residual block,

n bits of the pixel value of the residual block are positioned behind and adjacent to the first bit of the pixel value of the residual block, wherein the first bit is a bit with the value of 1 and the highest bit number in the pixel value of the residual block, i and N are positive integers, i is less than or equal to N, and N is less than M;

and obtaining the image block according to the processed residual error block and the predicted block of the image block.

In this embodiment of the present invention, the encoding end performs the inversion processing on the pixel value of the residual block, so that the data size of the residual block can be reduced when the pixel value of the residual block includes a continuous placeholder, so that the code stream generated by encoding occupies less storage space, and the decoding end performs the inversion processing on the residual block obtained by decoding, so that the residual block processed by the encoding end (the inversion processing) can be restored, and a final image block is obtained according to the processed residual block.

With reference to the second aspect, in some implementations of the second aspect, obtaining, from the code stream, a residual block of the image block includes: and performing inverse transformation, inverse quantization and entropy decoding on the code stream to obtain a residual block.

With reference to the second aspect, in some implementations of the second aspect, obtaining, from the code stream, a residual block of the image block includes: and performing entropy decoding treatment on the code stream to obtain a residual block.

With reference to the second aspect, in some implementations of the second aspect, the code stream is obtained by encoding a positioning bit layer.

With reference to the second aspect, in certain implementations of the second aspect, locating pixel values of the map layer includes rasterized elevation data.

With reference to the second aspect, in certain implementations of the second aspect, the value of M is any one of 8, 10, and 12.

In a third aspect, there is provided an image decoding method, the method comprising: acquiring a code stream; acquiring a residual block of an image block and a prediction block of the image block according to the code stream; obtaining an image block according to the residual block of the image block and the prediction block of the image block; and processing the image block to obtain a processed image block.

The value of the 1 st bit in the N bits of the processed image block is opposite to the value of the 1 st bit in the N bits of the image block, and the value of the i+1 th bit in the N bits of the processed image block is the result of exclusive-or processing of the i+1 th bit in the N bits of the image block and the i th bit in the N bits of the processed image block.

The N bits of the pixel value of the image block are located after and adjacent to the first bit of the pixel value of the image block, which is the bit of the pixel value of the image block having the value 1 and the highest number of bits, or the N bits of the pixel value of the image block are located after and adjacent to the highest bit of the pixel value of the image block.

The N bits of the pixel value of the image block are the same as the N bits of the pixel value of the processed image block, the bit number of the ith bit is higher than the bit number of the (i+1) th bit, i and N are positive integers, i is less than or equal to N, and N is less than M.

In the embodiment of the present application, the encoding end performs the exclusive-or processing on the pixel values of the image blocks, so that the data size of the image blocks can be reduced when the pixel values of the image blocks include continuous placeholders, so that the code stream generated by encoding occupies less storage space, and the decoding end performs the exclusive-or processing on the image blocks obtained by decoding, so that the image blocks processed by the encoding end (exclusive-or processing) can be restored, and a final image block is obtained.

With reference to the third aspect, in some implementations of the third aspect, acquiring, from the code stream, a residual block of the image block includes: and performing inverse transformation, inverse quantization and entropy decoding on the code stream to obtain a residual block.

With reference to the third aspect, in some implementations of the third aspect, acquiring, from the code stream, a residual block of the image block includes: and performing entropy decoding treatment on the code stream to obtain a residual block. The decoding mode for only performing entropy decoding corresponds to lossless encoding, and the encoding mode can avoid image distortion as far as possible and ensure the final display effect of the image.

With reference to the third aspect, in some implementations of the third aspect, the code stream is encoded with a positioning bit map layer.

With reference to the third aspect, in some implementations of the third aspect, the locating map layer includes rasterized elevation data.

With reference to the third aspect, in some implementations of the third aspect, the value of M is any one of 8, 10, and 12.

In a fourth aspect, there is provided an image decoding method, the method comprising: acquiring a code stream; according to the code stream, obtaining a residual block of an image block and a prediction block of the image block, wherein the pixel value of the residual block is represented by M bits, the value of each bit is 0 or 1, and M is an integer greater than 1; processing the residual block to obtain a processed residual block; and obtaining the image block according to the processed residual error block and the predicted block of the image block.

The value of the 1 st bit in the N bits of the residual block after processing is opposite to the value of the 1 st bit in the N bits of the residual block, and the value of the (i+1) th bit in the N bits of the residual block after processing is the result of exclusive OR processing of the (i+1) th bit in the N bits of the residual block and the (i) th bit in the N bits of the residual block after processing.

The N bits of the pixel value of the residual block are located after and adjacent to the first bit of the pixel value of the residual block, which is the bit having the value 1 and the highest number of bits in the pixel value of the residual block, or the N bits of the pixel value of the residual block are located after and adjacent to the highest number of bits of the pixel value of the residual block.

N bits of the pixel value of the residual block are the same as the N bits of the pixel value of the processed residual block, the bit number of the ith bit is higher than the bit number of the (i+1) th bit, i and N are positive integers, i is less than or equal to N, and N is less than M;

in this embodiment of the present application, the encoding end performs an exclusive-or process on the pixel value of the residual block, so that the data size of the residual block can be reduced when the pixel value of the residual block includes a continuous placeholder, so that the code stream generated by encoding occupies less storage space, and the decoding end performs an exclusive-or process on the residual block obtained by decoding, so that the residual block processed by the encoding end (exclusive-or process) can be restored, and a final image block is obtained according to the processed residual block.

With reference to the fourth aspect, in some implementations of the fourth aspect, acquiring, from the code stream, a residual block of the image block includes: and performing inverse transformation, inverse quantization and entropy decoding on the code stream to obtain a residual block.

With reference to the fourth aspect, in some implementations of the fourth aspect, acquiring, from the code stream, a residual block of the image block includes: and performing entropy decoding treatment on the code stream to obtain a residual block.

With reference to the fourth aspect, in some implementations of the fourth aspect, the code stream is obtained by encoding a positioning bit layer.

With reference to the fourth aspect, in some implementations of the fourth aspect, locating the pixel values of the image layer includes rasterized elevation data.

With reference to the fourth aspect, in some implementations of the fourth aspect, the value of M is any one of 8, 10, and 12.

In a fifth aspect, there is provided an image encoding method, the method comprising: obtaining an image block, wherein the pixel value of the image block is represented by M bits, the value of each bit is 0 or 1, and M is an integer greater than 1; processing the image block to obtain a processed image block; predicting the processed image block to obtain a residual block; and encoding the residual block to obtain a code stream.

In the embodiment of the application, the encoding end performs the inversion processing on the pixel value of the image block, so that the data volume of the image block can be reduced under the condition that the pixel value of the image block contains continuous placeholders, and the code stream generated by encoding occupies less storage space.

With reference to the fifth aspect, in some implementations of the fifth aspect, encoding the residual block to obtain a code stream includes: and carrying out transformation, quantization and entropy coding on the residual block to obtain a coded code stream.

By performing lossy encoding, the encoded code stream can occupy as little memory space as possible.

With reference to the fifth aspect, in some implementations of the fifth aspect, encoding the residual block to obtain a code stream includes: and performing entropy coding treatment on the residual block to obtain a coded code stream.

Through lossless coding, image distortion can be avoided as much as possible, and the final display effect of the image is ensured.

With reference to the fifth aspect, in certain implementations of the fifth aspect, the image blocks are from a positioning map layer.

With reference to the fifth aspect, in certain implementations of the fifth aspect, locating pixel values of the map layer includes rasterized elevation data.

With reference to the fifth aspect, in certain implementations of the fifth aspect, M has a value of any one of 8, 10, and 12.

In a sixth aspect, there is provided an image encoding method, the method comprising: acquiring an image block; predicting the image block to obtain a residual block of the image block, wherein the pixel value of the residual block is represented by M bits, the value of each bit is 0 or 1, and M is an integer greater than 1; processing the residual block to obtain a processed residual block; and coding the processed residual block to obtain a code stream.

The value of the ith bit in the N bits of the pixel value of the residual block is opposite to the value of the ith bit in the N bits of the pixel value of the processed residual block, and the N bits of the pixel value of the residual block are the same as the positions of the N bits of the pixel value of the processed residual block.

in the embodiment of the present application, the encoding end performs exclusive-or processing on the pixel values of the residual block, so that the data size of the residual block can be reduced when the pixel values of the residual block include continuous placeholders, and the code stream generated by encoding occupies less storage space.

With reference to the sixth aspect, in some implementations of the sixth aspect, encoding the residual block to obtain a code stream includes: and carrying out transformation, quantization and entropy coding on the residual block to obtain a coded code stream.

With reference to the sixth aspect, in some implementations of the sixth aspect, encoding the residual block to obtain a code stream includes: and performing entropy coding treatment on the residual block to obtain a coded code stream.

With reference to the sixth aspect, in some implementations of the sixth aspect, the image blocks are from a positioning map layer.

With reference to the sixth aspect, in some implementations of the sixth aspect, locating pixel values of the map layer includes rasterized elevation data.

With reference to the sixth aspect, in certain implementations of the sixth aspect, the value of M is any one of 8, 10, and 12.

In a seventh aspect, there is provided an image encoding method, the method comprising: obtaining an image block, wherein the pixel value of the image block is represented by M bits, the value of each bit is 0 or 1, and M is an integer greater than 1; processing the image block to obtain a processed image block; predicting the processed image block to obtain a residual block; and encoding the residual block to obtain a code stream.

The value of the 1 st bit in the N bits of the processed image block is opposite to the value of the 1 st bit in the N bits of the image block, and the value of the (i+1) th bit in the N bits of the processed image block is the result of exclusive OR processing of the (i+1) th bit in the N bits of the image block and the (i) th bit in the N bits of the processed image block.

In the embodiment of the application, the encoding end performs exclusive or processing on the pixel values of the image blocks, so that the data volume of the image blocks can be reduced under the condition that the pixel values of the image blocks contain continuous placeholders, and the code stream generated by encoding occupies less storage space.

With reference to the seventh aspect, in some implementations of the seventh aspect, encoding the residual block to obtain a code stream includes: and carrying out transformation, quantization and entropy coding on the residual block to obtain a coded code stream.

With reference to the seventh aspect, in some implementations of the seventh aspect, encoding the residual block to obtain a code stream includes: and performing entropy coding treatment on the residual block to obtain a coded code stream.

With reference to the seventh aspect, in some implementations of the seventh aspect, the image blocks are from a positioning map layer.

With reference to the seventh aspect, in some implementations of the seventh aspect, locating the pixel values of the map layer includes rasterized elevation data.

With reference to the seventh aspect, in certain implementations of the seventh aspect, the value of M is any one of 8, 10, and 12.

An eighth aspect provides an image encoding method, the method comprising: acquiring an image block; predicting the image block to obtain a residual block of the image block, wherein the pixel value of the residual block is represented by M bits, the value of each bit is 0 or 1, and M is an integer greater than 1; processing the residual block to obtain a processed residual block; and coding the processed residual block to obtain a code stream.

The value of the ith bit in the N bits of the pixel value of the residual block is opposite to the value of the ith bit in the N bits of the pixel value of the processed residual block, and the value of the (i+1) th bit in the N bits of the processed residual block is the result of exclusive OR processing of the value of the (i+1) th bit in the N bits of the residual block and the (i) th bit in the N bits of the processed residual block.

The N bits of the pixel value of the residual block are the same as the N bits of the pixel value of the processed residual block, the bit number of the ith bit is higher than the bit number of the (i+1) th bit, i and N are positive integers, i is less than or equal to N, and N is less than M.

With reference to the eighth aspect, in some implementations of the eighth aspect, encoding the residual block to obtain a code stream includes: and carrying out transformation, quantization and entropy coding on the residual block to obtain a coded code stream.

With reference to the eighth aspect, in some implementations of the eighth aspect, encoding the residual block to obtain a code stream includes: and performing entropy coding treatment on the residual block to obtain a coded code stream.

With reference to the eighth aspect, in some implementations of the eighth aspect, the image blocks are from a positioning layer.

With reference to the eighth aspect, in some implementations of the eighth aspect, locating pixel values of the map layer includes rasterized elevation data.

With reference to the eighth aspect, in some implementations of the eighth aspect, M has a value of any one of 8, 10, and 12.

In a ninth aspect, there is provided an image encoding method, the method comprising: acquiring an image, wherein the pixel value of the image is represented by M bits, the value of each bit is 0 or 1, and M is an integer greater than 1; processing the image to obtain a processed image; and encoding the processed image to obtain a code stream.

The value of the ith bit in the N bits of the pixel value of the image is opposite to the value of the ith bit in the N bits of the pixel value of the processed image, and the N bits of the pixel value of the image are the same as the positions of the N bits of the pixel value of the processed image.

N bits of the pixel value of the image are positioned behind and adjacent to the first bit of the pixel value of the image, wherein the first bit is the bit with the value of 1 and the highest bit number in the pixel value of the image, i and N are positive integers, i is less than or equal to N, and N is less than M.

The acquired image may be an image to be encoded.

In the embodiment of the application, the encoding end performs the inverse processing on the image before encoding the image, so that the data volume of the image can be reduced under the condition that the pixel value of the image contains continuous placeholders, and the code stream generated by encoding occupies less storage space.

The encoding of the processed image to obtain the code stream may be performed by dividing the image into image blocks and then encoding each image block to generate the code stream.

The above-described processed image may be encoded using either lossy or lossless encoding.

It should be understood that, after the code stream encoded by the method of the ninth aspect is obtained, the decoding end may first decode according to the code stream to obtain an image, and perform inverse processing on the pixel value of the image after the image is obtained, so as to obtain a final image.

In a tenth aspect, there is provided an image encoding method, the method comprising: acquiring an image, wherein the pixel value of the image is represented by M bits, the value of each bit is 0 or 1, and M is an integer greater than 1; processing the image to obtain a processed image; and encoding the processed image to obtain a code stream.

Wherein the value of the 1 st bit in the N bits of the processed image is opposite to the value of the 1 st bit in the N bits of the image, the value of the (i+1) th bit in the N bits of the processed image is the result of exclusive OR processing of the (i+1) th bit in the N bits of the image and the (i) th bit in the N bits of the processed image,

the N bits of the pixel value of the image are located after and adjacent to the first bit of the pixel value of the image, which is the bit of the pixel value of the image having a value of 1 and the highest number of bits, or the N bits of the pixel value of the image are located after and adjacent to the highest number of bits of the pixel value of the image,

N bits of the pixel value of the image are the same as the N bits of the pixel value of the processed image, the bit number of the ith bit is higher than the bit number of the (i+1) th bit, i and N are positive integers, i is less than or equal to N, and N is less than M;

the acquired image may be an image to be encoded.

In the embodiment of the application, the encoding end performs exclusive-or processing on the image before encoding the image, so that the data volume of the image can be reduced under the condition that the pixel value of the image contains continuous placeholders, and the code stream generated by encoding occupies less storage space.

Accordingly, after the code stream obtained by encoding by the method of the tenth aspect is obtained, the decoding end may first decode according to the code stream to obtain an image, and perform an inverse process of exclusive-or processing on the pixel value of the image after the image is obtained (see, for details, the process of pixel values of the residual block in the third aspect and the fourth aspect) to obtain a final image.

An eleventh aspect provides an image decoding apparatus comprising means corresponding to the method of any one of the first to fourth aspects described above, the corresponding means being capable of carrying out the steps of the method of any one of the first to fourth aspects described above.

In a twelfth aspect, there is provided an image encoding apparatus including modules corresponding to the method of any one of the fifth to tenth aspects described above, the corresponding modules being capable of implementing the respective steps of the method of any one of the fifth to tenth aspects described above.

The image decoding apparatus in the eleventh aspect or the image encoding apparatus in the twelfth aspect may include one or more modules, any one of which may be constituted by any one of a circuit, a field programmable gate array FPGA, an application specific integrated circuit ASIC, and a general-purpose processor.

In a thirteenth aspect, there is provided an image decoding apparatus comprising a memory and a processor that invokes program code stored in the memory to perform the method of any one of the first to fourth aspects.

In a fourteenth aspect, there is provided an image encoding apparatus comprising a memory and a processor that invokes program code stored in the memory to perform the method of any one of the fifth to tenth aspects.

Optionally, the memory is a nonvolatile memory.

Optionally, the memory and the processor are coupled to each other.

The image decoding apparatus in the eleventh or thirteenth aspect may also be referred to as an image decoder, and the image encoding apparatus in the twelfth or fourteenth aspect may also be referred to as an image encoder.

In a fifteenth aspect, embodiments of the present application provide a computer-readable storage medium storing instructions that cause one or more processors to perform the method of any one of the first to tenth aspects.

Any one of the one or more processors may be comprised of any one of a circuit, a field programmable gate array FPGA, an application specific integrated circuit ASIC, and a general purpose processor.

In a sixteenth aspect, embodiments of the present application provide a computer program product for, when run on a computer, causing the computer to perform some or all of the steps of the method of any one of the first to tenth aspects.

Drawings

FIG. 1 is a schematic block diagram of an example video encoding system for implementing embodiments of the present application;

FIG. 2 is a schematic block diagram of an example video encoder for implementing embodiments of the present application;

FIG. 3 is a schematic block diagram of an example video decoder for implementing embodiments of the present application;

FIG. 4 is a schematic block diagram of an example video coding system for implementing embodiments of the present application;

fig. 5 is a schematic block diagram of an example video coding apparatus for implementing an embodiment of the present application;

FIG. 6 is a schematic block diagram of an example encoding or decoding apparatus for implementing embodiments of the present application;

FIG. 7 is a schematic diagram of spatial and temporal candidate motion information for a current coding unit;

FIG. 8 is a schematic diagram of the conversion of 3D point cloud data into 2D planar data;

FIG. 9 is a schematic diagram of the duty cycle of different characters in elevation data;

fig. 10 is a schematic diagram of a process of an image decoding method of an embodiment of the present application;

fig. 11 is a schematic flowchart of an image decoding method of an embodiment of the present application;

fig. 12 is a schematic flowchart of an image decoding method of an embodiment of the present application;

fig. 13 is a schematic flowchart of an image decoding method of an embodiment of the present application;

FIG. 14 is a schematic flow chart diagram of an image encoding method of an embodiment of the present application;

FIG. 15 is a schematic flow chart of an image encoding method of an embodiment of the present application;

FIG. 16 is a schematic flow chart diagram of an image encoding method of an embodiment of the present application;

FIG. 17 is a schematic diagram of coding performance corresponding to an inverting operation;

FIG. 18 is a diagram of corresponding encoding performance using an exclusive OR operation;

FIG. 19 is a schematic flow chart diagram of an image encoding method of an embodiment of the present application;

FIG. 20 is a schematic flow chart of an image encoding method of an embodiment of the present application;

FIG. 21 is a schematic flow chart of an image encoding method of an embodiment of the present application;

FIG. 22 is a schematic flow chart of processing elevation data of a positioning map layer;

FIG. 23 is a schematic flow chart of processing elevation data of a positioning map layer;

FIG. 24 is a schematic flow chart of processing elevation data of a positioning map layer;

FIG. 25 is a schematic flow chart of an image encoding method of an embodiment of the present application;

FIG. 26 is a schematic flow chart of an image encoding method of an embodiment of the present application;

fig. 27 is a schematic block diagram of an image decoding apparatus of an embodiment of the present application;

fig. 28 is a schematic block diagram of an image encoding apparatus of an embodiment of the present application;

Fig. 29 is a schematic block diagram of an image decoding apparatus of an embodiment of the present application;

fig. 30 is a schematic block diagram of an image encoding apparatus of an embodiment of the present application.

Detailed Description

The technical solutions in the present application will be described below with reference to the accompanying drawings.

In the following description, reference is made to the accompanying drawings which form a part hereof and which show by way of illustration specific aspects in which embodiments of the application may be practiced. It is to be understood that the embodiments of the present application may also be used in other aspects and may include structural or logical changes not depicted in the drawings. The following detailed description is, therefore, not to be taken in a limiting sense, and the scope of the present application is defined by the appended claims.

For example, it should be understood that the disclosure in connection with the described methods may be equally applicable to a corresponding apparatus or system performing the methods, and vice versa.

As another example, if one or more specific method steps are described, the corresponding apparatus may comprise one or more units, such as functional units, to perform the one or more described method steps (e.g., one unit performs one or more steps, or multiple units, each of which performs one or more of the multiple steps), even if such one or more units are not explicitly described or illustrated in the figures.

Furthermore, if a specific apparatus is described based on one or more units, such as functional units, the corresponding method may include one step to perform the function of the one or more units (e.g., one step to perform the function of the one or more units, or multiple steps, each of which performs the function of one or more units, even if such one or more steps are not explicitly described or illustrated in the figures). Further, it is to be understood that features of the various exemplary embodiments and/or aspects described herein may be combined with each other, unless explicitly stated otherwise.

The technical scheme related to the embodiment of the application can be applied to the H.266 standard and future video coding standards. The terminology used in the description section of the present application is for the purpose of describing particular embodiments of the present application only and is not intended to be limiting of the present application. Some concepts that may be related to embodiments of the present application are briefly described below.

The image encoding and decoding in this application are the same as the encoding and decoding of video images, and some basic processes and related matters of the encoding and decoding of video images are described in detail below.

Video coding generally refers to processing a sequence of pictures that form a video or video sequence. In the field of video coding, the terms "picture", "frame" or "image" may be used as synonyms. Video encoding as used herein refers to video encoding or video decoding. Video encoding is performed on the source side, typically including processing (e.g., by compression) the original video picture to reduce the amount of data required to represent the video picture, thereby more efficiently storing and/or transmitting. Video decoding is performed on the destination side, typically involving inverse processing with respect to the encoder to reconstruct the video pictures. The embodiment relates to video picture "encoding" is understood to relate to "encoding" or "decoding" of a video sequence. The combination of the encoding portion and the decoding portion is also called codec (encoding and decoding).

A video sequence comprises a series of pictures (pictures) which are further divided into slices (slices) which are further divided into blocks (blocks). Video coding performs coding processing in units of blocks, and in some new video coding standards, the concept of blocks is further extended. For example, in the h.264 standard, there are Macro Blocks (MBs), which can be further divided into a plurality of prediction blocks (partition) that can be used for predictive coding. In the high performance video coding (high efficiency video coding, HEVC) standard, basic concepts such as a Coding Unit (CU), a Prediction Unit (PU), and a Transform Unit (TU) are adopted, and various block units are functionally divided and described by using a brand new tree-based structure. For example, a CU may be divided into smaller CUs according to a quadtree, and the smaller CUs may continue to be divided, thereby forming a quadtree structure, where a CU is a basic unit for dividing and encoding an encoded image. Similar tree structures exist for PUs and TUs, which may correspond to prediction blocks, being the basic unit of predictive coding. The CU is further divided into a plurality of PUs according to a division pattern. The TU may correspond to a transform block, which is a basic unit for transforming a prediction residual. However, whether CU, PU or TU, essentially belongs to the concept of blocks (or picture blocks).

For example, in HEVC, a CTU is split into multiple CUs by using a quadtree structure denoted as a coding tree. A decision is made at the CU level whether to encode a picture region using inter-picture (temporal) or intra-picture (spatial) prediction. Each CU may be further split into one, two, or four PUs depending on the PU split type. The same prediction process is applied within one PU and the relevant information is transmitted to the decoder on a PU basis. After the residual block is obtained by applying the prediction process based on the PU split type, the CU may be partitioned into Transform Units (TUs) according to other quadtree structures similar to the coding tree for the CU. In a recent development of video compression technology, a quadtree and binary tree (QTBT) partition frame is used to partition the encoded blocks. In QTBT block structures, a CU may be square or rectangular in shape.

Herein, for convenience of description and understanding, an image block to be encoded in a current encoded image may be referred to as a current image block, for example, in encoding, a block currently being encoded; in decoding, a block currently being decoded is referred to. A decoded image block in a reference image used for prediction of a current image block is referred to as a reference block, i.e. a reference block is a block providing a reference signal for the current image block, wherein the reference signal represents pixel values within the image block. A block in the reference image that provides a prediction signal for the current image block may be referred to as a prediction block, where the prediction signal represents pixel values or sample signals within the prediction block. For example, after traversing multiple reference blocks, the best reference block is found, which will provide prediction for the current image block, which is referred to as the prediction block.

In the case of lossless video coding, the original video picture may be reconstructed, i.e., the reconstructed video picture has the same quality as the original video picture (assuming no transmission loss or other data loss during storage or transmission). In the case of lossy video coding, the amount of data needed to represent a video picture is reduced by performing further compression, e.g. quantization, whereas the decoder side cannot reconstruct the video picture completely, i.e. the quality of the reconstructed video picture is lower or worse than the quality of the original video picture.

Several video coding standards of h.261 belong to the "lossy hybrid video codec" (i.e. spatial and temporal prediction in the sample domain is combined with 2D transform coding in the transform domain for applying quantization). Each picture of a video sequence is typically partitioned into non-overlapping sets of blocks, typically encoded at the block level. In other words, the encoder side typically processes, i.e. encodes, video at the block (video block) level, e.g. generates a prediction block by spatial (intra-picture) prediction and temporal (inter-picture) prediction, subtracts the prediction block from the current image block (the currently processed or to-be-processed block) to obtain a residual block, transforms the residual block in the transform domain and quantizes the residual block to reduce the amount of data to be transmitted (compressed), while the decoder side applies the inverse processing part of the relative encoder to the encoded or compressed block to reconstruct the current image block for representation. In addition, the encoder replicates the decoder processing loop so that the encoder and decoder generate the same predictions (e.g., intra-prediction and inter-prediction) and/or reconstructions for processing, i.e., encoding, the subsequent blocks.

The system architecture to which the embodiments of the present application apply is described below. Referring to fig. 1, fig. 1 schematically shows a block diagram of a video encoding and decoding system 10 to which embodiments of the present application are applied. As shown in fig. 1, video encoding and decoding system 10 may include a source device 12 and a destination device 14, source device 12 generating encoded video data, and thus source device 12 may be referred to as a video encoding apparatus. Destination device 14 may decode encoded video data generated by source device 12, and thus destination device 14 may be referred to as a video decoding apparatus. Various embodiments of source device 12, 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, read-only memory (ROM), random access memory (random access memory) RAM, erasable programmable read-only memory (EPROM), flash memory, or any other medium from which desired program code can be stored in the form of instructions or data structures accessible by a computer, as described herein. 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, telephone handsets such as so-called "smart" phones, televisions, cameras, display devices, digital media players, video game consoles, vehicle mount computers, wireless communication devices, or the like.

Although fig. 1 depicts 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, i.e., source device 12 or corresponding functionality and destination device 14 or corresponding functionality. In such embodiments, the source device 12 or corresponding functionality and the destination device 14 or corresponding functionality may be implemented using the same hardware and/or software, or using separate hardware and/or software, or any combination thereof.

A communication connection may be made between source device 12 and destination device 14 via link 13, and destination device 14 may receive encoded video data from source device 12 via link 13. Link 13 may include one or more media or devices capable of moving encoded video data from source device 12 to destination device 14. In one example, link 13 may include one or more communication media that enable source device 12 to transmit encoded video data directly to destination device 14 in real-time. In this example, source apparatus 12 may modulate the encoded video data according to a communication standard, such as a wireless communication protocol, and may transmit the modulated video data to destination apparatus 14. The one or more communication media may include wireless and/or wired communication media such as a 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, a wide area network, or a 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.

Source device 12 includes an encoder 20 and, alternatively, source device 12 may also include a picture source 16, a picture preprocessor 18, and a communication interface 22. In a specific implementation, the encoder 20, the picture source 16, the picture preprocessor 18, and the communication interface 22 may be hardware components in the source device 12 or may be software programs in the source device 12. The descriptions are as follows:

the picture source 16 may include or be any type of picture capture device for capturing, for example, real world pictures, and/or any type of picture or comment (for screen content encoding, some text on the screen is also considered part of the picture or image to be encoded), for example, a computer graphics processor for generating computer animated pictures, or any type of device for capturing and/or providing real world pictures, computer animated pictures (e.g., screen content, virtual Reality (VR) pictures), and/or any combination thereof (e.g., live (augmented reality, AR) pictures). Picture source 16 may be a camera for capturing pictures or a memory for storing pictures, picture source 16 may also include any type of (internal or external) interface for storing previously captured or generated pictures and/or for capturing or receiving pictures. When picture source 16 is a camera, picture source 16 may be, for example, an integrated camera, either local or integrated in the source device; when picture source 16 is memory, picture source 16 may be local or integrated memory integrated in the source device, for example. When the picture source 16 comprises an interface, the interface may for example be an external interface receiving pictures from an external video source, for example an external picture capturing device, such as a camera, an external memory or an external picture generating device, for example an external computer graphics processor, a computer or a server. The interface may be any kind of interface according to any proprietary or standardized interface protocol, e.g. a wired or wireless interface, an optical interface.

Wherein a picture can be regarded as a two-dimensional array or matrix of pixel elements. The pixels in the array may also be referred to as sampling points. The number of sampling points of the array or picture in the horizontal and vertical directions (or axes) defines the size and/or resolution of the picture. To represent color, three color components are typically employed, i.e., a picture may be represented as or contain three sample arrays. For example, in RBG format or color space, the picture includes corresponding red, green, and blue sample arrays. However, in video coding, each pixel is typically represented in a luminance/chrominance format or color space, e.g., for a picture in YUV format, comprising a luminance component indicated by Y (which may sometimes also be indicated by L) and two chrominance components indicated by U and V. The luminance (luma) component Y represents the luminance or grayscale level intensity (e.g., the same in a grayscale picture), while the two chrominance (chroma) components U and V represent the chrominance or color information components. Accordingly, a picture in YUV format includes a luminance sample array of luminance sample values (Y) and two chrominance sample arrays of chrominance values (U and V). Pictures in RGB format may be converted or transformed into YUV format and vice versa, a process also known as color transformation or conversion. If the picture is black and white, the picture may include only an array of luma samples. In the present embodiment, the picture transmitted by the picture source 16 to the picture processor may also be referred to as the original picture data 17.

A picture preprocessor 18 for receiving the original picture data 17 and performing preprocessing on the original picture data 17 to obtain a preprocessed picture 19 or preprocessed picture data 19. For example, the preprocessing performed by the picture preprocessor 18 may include truing, color format conversion (e.g., from RGB format to YUV format), toning, or denoising.

Encoder 20 (or video encoder 20) receives pre-processed picture data 19, and processes pre-processed picture data 19 using an associated prediction mode (e.g., a prediction mode in various embodiments herein) to provide encoded picture data 21 (details of the structure of encoder 20 will be described further below based on fig. 2 or fig. 4 or fig. 5). In some embodiments, encoder 20 may be used to perform various embodiments described below to enable application of the encoding methods described herein on the encoding side.

Communication interface 22 may be used to receive encoded picture data 21 and may transmit encoded picture data 21 over link 13 to destination device 14 or any other device (e.g., memory) for storage or direct reconstruction, which may be any device for decoding or storage. The communication interface 22 may be used, for example, to encapsulate the encoded picture data 21 into a suitable format, such as a data packet, for transmission over the link 13.

Destination device 14 includes a decoder 30, and alternatively destination device 14 may also include a communication interface 28, a picture post-processor 32, and a display device 34. The descriptions are as follows:

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

Both communication interface 28 and communication interface 22 may be configured as unidirectional communication interfaces or bidirectional communication interfaces and may be used, for example, to send and receive messages to establish connections, to acknowledge and to exchange any other information related to the communication link and/or to the transmission of data, for example, encoded picture data transmissions.

Decoder 30 (or referred to as decoder 30) for receiving encoded picture data 21 and providing decoded picture data 31 or decoded picture 31 (details of the structure of decoder 30 will be described below further based on fig. 3 or fig. 4 or fig. 5). In some embodiments, decoder 30 may be used to perform various embodiments described below to enable application of the decoding methods described herein on the decoding side.

A picture post-processor 32 for performing post-processing on the decoded picture data 31 (also referred to as reconstructed slice data) to obtain post-processed picture data 33. The post-processing performed by the picture post-processor 32 may include: color format conversion (e.g., from YUV format to RGB format), toning, truing, or resampling, or any other process, may also be used to transmit post-processed picture data 33 to display device 34.

A display device 34 for receiving the post-processed picture data 33 for displaying pictures to, for example, a user or viewer. The display device 34 may be or include any type of display for presenting reconstructed pictures, for example, an integrated or external display or monitor. For example, the display may include a liquid crystal display (liquid crystal display, LCD), an organic light emitting diode (organic light emitting diode, OLED) display, a plasma display, a projector, a micro LED display, a liquid crystal on silicon (liquid crystal on silicon, LCoS), a digital light processor (digital light processor, DLP), or any other type of display.

Although source device 12 and destination device 14 are depicted in fig. 1 as separate devices, device embodiments may also include both source device 12 and destination device 14 or both functionality, i.e., source device 12 or corresponding functionality and destination device 14 or corresponding functionality. In such embodiments, the source device 12 or corresponding functionality and the destination device 14 or corresponding functionality may be implemented using the same hardware and/or software, or using separate hardware and/or software, or any combination thereof.

It will be apparent to those skilled in the art from this description that the functionality of the different units or the presence and (exact) division of the functionality of the source device 12 and/or destination device 14 shown in fig. 1 may vary depending on the actual device and application. Source device 12 and destination device 14 may comprise any of a variety of devices, including any type of handheld or stationary device, such as a notebook or laptop computer, mobile phone, smart phone, tablet or tablet computer, video camera, desktop computer, set-top box, television, camera, in-vehicle device, display device, digital media player, video game console, video streaming device (e.g., content service server or content distribution server), broadcast receiver device, broadcast transmitter device, etc., and may not use or use any type of operating system.

Encoder 20 and decoder 30 may each be implemented as any of a variety of suitable circuits, such as, for example, one or more microprocessors, digital signal processors (digital signal processor, DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), discrete logic, hardware or any combinations thereof. If the techniques are implemented in part in software, an apparatus may store instructions for the software in a suitable non-transitory computer-readable storage medium and may execute the instructions in hardware using one or more processors to perform the techniques of this application. Any of the foregoing (including hardware, software, a combination of hardware and software, etc.) may be considered one or more processors.

In some cases, the video encoding and decoding system 10 shown in fig. 1 is merely an example, and the techniques of this disclosure may be applied to video encoding settings (e.g., video encoding or video decoding) that do not necessarily involve any data communication between encoding and decoding devices. In other examples, the data may be retrieved from local memory, streamed over a network, and the like. The video encoding device may encode and store data to the memory and/or the video decoding device may retrieve and decode data from the memory. In some examples, encoding and decoding are performed by devices that do not communicate with each other, but instead only encode data to memory and/or retrieve data from memory and decode data.

Referring to fig. 2, fig. 2 shows a schematic/conceptual block diagram of an example of an encoder 20 for implementing an embodiment of the present application. In the example of fig. 2, 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 (decoded picture buffer, DPB) 230, a prediction processing unit 260, and an entropy encoding unit 270. The prediction processing unit 260 may include an inter prediction unit 244, an intra prediction unit 254, and a mode selection unit 262. The inter prediction unit 244 may include a motion estimation unit and a motion compensation unit (not shown). The encoder 20 shown in fig. 2 may also be referred to as a hybrid video encoder or a video encoder according to a hybrid video codec.

For example, the residual calculation unit 204, the transform processing unit 206, the quantization unit 208, the prediction processing unit 260 and the entropy encoding unit 270 form a forward signal path of the encoder 20, whereas for example the inverse quantization unit 210, the inverse transform processing unit 212, the reconstruction unit 214, the buffer 216, the loop filter 220, the decoded picture buffer (decoded picture buffer, DPB) 230, the prediction processing unit 260 form a backward signal path of the encoder, wherein the backward signal path of the encoder corresponds to the signal path of the decoder (see decoder 30 in fig. 3).

Encoder 20 receives picture 201 or an image block 203 of picture 201, e.g., a picture in a sequence of pictures forming a video or video sequence, through, e.g., input 202. Image block 203 may also be referred to as a current picture block or a picture block to be encoded, and picture 201 may be referred to as a current picture or a picture to be encoded (especially when distinguishing the current picture from other pictures in video encoding, such as previously encoded and/or decoded pictures in the same video sequence, i.e., a video sequence that also includes the current picture).

An embodiment of encoder 20 may comprise a partitioning unit (not shown in fig. 2) for partitioning picture 201 into a plurality of blocks, e.g. image blocks 203, typically into a plurality of non-overlapping blocks. The segmentation unit may be used to use the same block size for all pictures in the video sequence and a corresponding grid defining the block size, or to alter the block size between pictures or subsets or groups of pictures and to segment each picture into corresponding blocks.

In one example, prediction processing unit 260 of encoder 20 may be used to perform any combination of the above-described partitioning techniques.

Like picture 201, image block 203 is also or may be considered as a two-dimensional array or matrix of sampling points having sampling values, albeit of smaller size than picture 201. In other words, the image block 203 may comprise, for example, one sampling array (e.g., a luminance array in the case of a black-and-white picture 201) or three sampling arrays (e.g., one luminance array and two chrominance arrays in the case of a color picture) or any other number and/or class of arrays depending on the color format applied. The number of sampling points in the horizontal and vertical directions (or axes) of the image block 203 defines the size of the image block 203.

The encoder 20 as shown in fig. 2 is used for encoding a picture 201 block by block, for example, performing encoding and prediction for each image block 203.

The residual calculation unit 204 is configured to calculate a residual block 205 based on the picture image block 203 and the prediction block 265 (further details of the prediction block 265 are provided below), for example, by subtracting sample values of the prediction block 265 from sample values of the picture image block 203 on a sample-by-sample (pixel-by-pixel) basis to obtain the residual block 205 in a sample domain.

The transform processing unit 206 is configured to apply a transform, such as a discrete cosine transform (discrete cosine transform, DCT) or a discrete sine transform (discrete sine transform, DST), on the sample values of the residual block 205 to obtain transform coefficients 207 in the transform domain. The transform coefficients 207 may also be referred to as transform residual coefficients and represent the residual block 205 in the transform domain.

The transform processing unit 206 may be used to apply integer approximations of DCT/DST, such as the transforms specified for HEVC/H.265. Such integer approximations are typically scaled by some factor compared to the orthogonal DCT transform. To maintain the norms of the forward and inverse transformed processed residual blocks, an additional scaling factor is applied as part of the transformation process. The scaling factor is typically selected based on certain constraints, e.g., the scaling factor is a tradeoff between power of 2, bit depth of transform coefficients, accuracy, and implementation cost for shift operations, etc. For example, a specific scaling factor is specified for inverse transformation by, for example, the inverse transformation processing unit 212 on the decoder 30 side (and for corresponding inverse transformation by, for example, the inverse transformation processing unit 212 on the encoder 20 side), and accordingly, a corresponding scaling factor may be specified for positive transformation by the transformation processing unit 206 on the encoder 20 side.

The quantization unit 208 is for quantizing the transform coefficients 207, for example by applying scalar quantization or vector quantization, to obtain quantized transform coefficients 209. The quantized transform coefficients 209 may also be referred to as quantized residual coefficients 209. The quantization process may reduce the bit depth associated with some or all of the transform coefficients 207. For example, n-bit transform coefficients may be rounded down to m-bit transform coefficients during quantization, where n is greater than m. The quantization level may be modified by adjusting quantization parameters (quantization parameter, QP). For example, for scalar quantization, different scales may be applied to achieve finer or coarser quantization. Smaller quantization step sizes correspond to finer quantization, while larger quantization step sizes correspond to coarser quantization. The appropriate quantization step size may be indicated by a quantization parameter (quantization parameter, QP). For example, the quantization parameter may be an index of a predefined set of suitable quantization steps. For example, smaller quantization parameters may correspond to fine quantization (smaller quantization step size) and larger quantization parameters may correspond to coarse quantization (larger quantization step size) and vice versa. Quantization may involve division by a quantization step size and corresponding quantization or inverse quantization, e.g., performed by inverse quantization 210, or may involve multiplication by a quantization step size. Embodiments according to some standards, such as HEVC, may use quantization parameters to determine quantization step sizes. In general, the quantization step size may be calculated based on quantization parameters using a fixed-point approximation of an equation that includes division. Additional scaling factors may be introduced for quantization and inverse quantization to recover norms of residual blocks that may be modified due to the scale used in the fixed point approximation of the equation for quantization step size and quantization parameters. In one example embodiment, the inverse transformed and inverse quantized scales may be combined. Alternatively, a custom quantization table may be used and signaled from the encoder to the decoder, e.g., in a bitstream. Quantization is a lossy operation, where the larger the quantization step size, the larger the loss.

The inverse quantization unit 210 is configured to apply inverse quantization of the quantization unit 208 on the quantized coefficients to obtain inverse quantized coefficients 211, e.g., apply an inverse quantization scheme of the quantization scheme applied by the quantization unit 208 based on or using the same quantization step size as the quantization unit 208. The dequantized coefficients 211 may also be referred to as dequantized residual coefficients 211, correspond to the transform coefficients 207, although the losses due to quantization are typically different from the transform coefficients.

The inverse transform processing unit 212 is configured to apply an inverse transform of the transform applied by the transform processing unit 206, for example, an inverse discrete cosine transform (discrete cosine transform, DCT) or an inverse discrete sine transform (discrete sine transform, DST), to obtain an inverse transform block 213 in the sample domain. The inverse transform block 213 may also be referred to as an inverse transformed inverse quantized block 213 or an inverse transformed residual block 213.

A reconstruction unit 214 (e.g., a summer 214) is used to add the inverse transform block 213 (i.e., the reconstructed residual block 213) to the prediction block 265 to obtain the reconstructed block 215 in the sample domain, e.g., to add sample values of the reconstructed residual block 213 to sample values of the prediction block 265.

Alternatively, the buffer unit 216 of the line buffer 216 (or simply "buffer" 216) may be used to buffer or store the reconstructed block 215 and corresponding sample values for use in, for example, intra prediction. In other embodiments, the encoder may be configured to use the unfiltered reconstructed block and/or the corresponding sample values stored in the buffer unit 216 for any kind of estimation and/or prediction, such as intra prediction.

For example, embodiments of encoder 20 may be configured such that buffer unit 216 is used not only to store reconstructed blocks 215 for intra prediction 254, but also for loop filter unit 220 (not shown in fig. 2), and/or such that buffer unit 216 and decoded picture buffer unit 230 form one buffer, for example. Other embodiments may be used to use the filtered block 221 and/or blocks or samples (neither shown in fig. 2) from the decoded picture buffer 230 as an input or basis for the intra prediction 254.

The loop filter unit 220 (or simply loop filter 220) is configured to filter the reconstructed block 215 to obtain a filtered block 221, thereby facilitating pixel transitions or improving video quality. Loop filter unit 220 is intended to represent one or more loop filters, such as deblocking filters, sample-adaptive offset (SAO) filters, or other filters, such as bilateral filters, adaptive loop filters (adaptive loop filter, ALF), or sharpening or smoothing filters, or collaborative filters. Although loop filter unit 220 is shown in fig. 2 as an in-loop filter, in other configurations loop filter unit 220 may be implemented as a post-loop filter. The filtered block 221 may also be referred to as a filtered reconstructed block 221. Decoded picture buffer 230 may store the reconstructed encoded block after loop filter unit 220 performs a filtering operation on the reconstructed encoded block.

Embodiments of encoder 20 (and correspondingly loop filter unit 220) may be configured to output loop filter parameters (e.g., sample adaptive offset information), e.g., directly or after entropy encoding by entropy encoding unit 270 or any other entropy encoding unit, e.g., such that decoder 30 may receive and apply the same loop filter parameters for decoding.

Decoded picture buffer (decoded picture buffer, DPB) 230 may be a reference picture memory that stores reference picture data for use by encoder 20 in encoding video data. DPB 230 may be formed of any of a variety of memory devices, such as dynamic random access memory (dynamic random access memory, DRAM) (including Synchronous DRAM (SDRAM), magnetoresistive RAM (MRAM), resistive RAM (RRAM)), or other types of memory devices. DPB 230 and buffer 216 may be provided by the same memory device or separate memory devices. In a certain example, a decoded picture buffer (decoded picture buffer, DPB) 230 is used to store the filtered block 221. The decoded picture buffer 230 may further be used to store the same current picture or other previously filtered blocks, e.g., previously reconstructed and filtered blocks 221, of different pictures, e.g., previously reconstructed pictures, and may provide complete previously reconstructed, i.e., decoded pictures (and corresponding reference blocks and samples) and/or partially reconstructed current pictures (and corresponding reference blocks and samples), e.g., for inter prediction. In a certain example, if the reconstructed block 215 is reconstructed without in-loop filtering, the decoded picture buffer (decoded picture buffer, DPB) 230 is used to store the reconstructed block 215.

The prediction processing unit 260, also referred to as block prediction processing unit 260, is adapted to receive or obtain image blocks 203 (current image blocks 203 of a current picture 201) and reconstructed slice data, e.g. reference samples of the same (current) picture from the buffer 216 and/or reference picture data 231 of one or more previously decoded pictures from the decoded picture buffer 230, and to process such data for prediction, i.e. to provide a prediction block 265, which may be an inter-predicted block 245 or an intra-predicted block 255.

The mode selection unit 262 may be used to select a prediction mode (e.g., intra or inter prediction mode) and/or a corresponding prediction block 245 or 255 used as the prediction block 265 to calculate the residual block 205 and reconstruct the reconstructed block 215.

Embodiments of mode selection unit 262 may be used to select the prediction mode (e.g., from those supported by prediction processing unit 260) that provides the best match or minimum residual (minimum residual meaning better compression in transmission or storage), or that provides the minimum signaling overhead (minimum signaling overhead meaning better compression in transmission or storage), or both. The mode selection unit 262 may be adapted to determine a prediction mode based on a rate-distortion optimization (rate distortion optimization, RDO), i.e. to select the prediction mode that provides the least rate-distortion optimization, or to select a prediction mode for which the associated rate-distortion at least meets a prediction mode selection criterion.

The prediction processing performed by an instance of encoder 20 (e.g., by prediction processing unit 260) and the mode selection performed (e.g., by mode selection unit 262) will be explained in detail below.

As described above, the encoder 20 is configured to determine or select the best or optimal prediction mode from a (predetermined) set of prediction modes. The set of prediction modes may include, for example, intra prediction modes and/or inter prediction modes.

The set of intra prediction modes may include 35 different intra prediction modes, for example, a non-directional mode such as a DC (or mean) mode and a planar mode, or a directional mode as defined in h.265, or 67 different intra prediction modes, for example, a non-directional mode such as a DC (or mean) mode and a planar mode, or a directional mode as defined in h.266 under development.

In a possible implementation, the set of inter prediction modes may comprise, for example, advanced motion vector (advanced motion vector prediction, AMVP) modes and fusion (merge) modes depending on available reference pictures (i.e., at least part of the decoded pictures stored in the DBP230, for example, as described above) and other inter prediction parameters, for example, depending on whether the entire reference picture is used or whether only a portion of the reference picture is used, for example, a search window area surrounding an area of the current image block, to search for the best matching reference block, and/or depending on whether pixel interpolation, such as half-pixel and/or quarter-pixel interpolation, is applied, for example. In particular implementations, the set of inter prediction modes may include an improved control point-based AMVP mode of an embodiment of the present application, and an improved control point-based merge mode. In one example, intra-prediction unit 254 may be used to perform any combination of the inter-prediction techniques described below.

In addition to the above prediction modes, the present embodiments may also apply skip mode and/or direct mode.

The prediction processing unit 260 may be further operative to partition the image block 203 into smaller block partitions or sub-blocks, for example, by iteratively using a quad-tree (QT) partition, a binary-tree (BT) partition, or a ternary-tree (TT) partition, or any combination thereof, and to perform prediction for each of the block partitions or sub-blocks, for example, wherein the mode selection includes selecting a tree structure of the partitioned image block 203 and selecting a prediction mode applied to each of the block partitions or sub-blocks.

The inter prediction unit 244 may include a motion estimation (motion estimation, ME) unit (not shown in fig. 2) and a motion compensation (motion compensation, MC) unit (not shown in fig. 2). The motion estimation unit is used to receive or obtain a picture image block 203 (current picture image block 203 of current picture 201) and a decoded picture 231, or at least one or more previously reconstructed blocks, e.g. reconstructed blocks of one or more other/different previously decoded pictures 231, for motion estimation. For example, the video sequence may include a current picture and a previously decoded picture 31, or in other words, the current picture and the previously decoded picture 31 may be part of, or form, a sequence of pictures that form the video sequence.

For example, encoder 20 may be configured to select a reference block from a plurality of reference blocks of the same or different pictures of a plurality of other pictures, and provide the reference picture and/or an offset (spatial offset) between a position (X, Y coordinates) of the reference block and a position of a current image block to a motion estimation unit (not shown in fig. 2) as an inter prediction parameter. This offset is also called Motion Vector (MV).

The motion compensation unit is used to acquire inter prediction parameters and perform inter prediction based on or using the inter prediction parameters to acquire the inter prediction block 245. The motion compensation performed by the motion compensation unit (not shown in fig. 2) may involve fetching or generating a prediction block based on motion/block vectors determined by motion estimation (possibly performing interpolation of sub-pixel accuracy). Interpolation filtering may generate additional pixel samples from known pixel samples, potentially increasing the number of candidate prediction blocks available for encoding a picture block. Upon receiving the motion vector for the PU of the current picture block, motion compensation unit 246 may locate the prediction block to which the motion vector points in a reference picture list. Motion compensation unit 246 may also generate syntax elements associated with the blocks and video slices for use by decoder 30 in decoding the picture blocks of the video slices.

Specifically, the inter prediction unit 244 may transmit a syntax element including inter prediction parameters (such as indication information of an inter prediction mode selected for prediction of the current image block after traversing a plurality of inter prediction modes) to the entropy encoding unit 270. In a possible application scenario, if the inter prediction mode is only one, the inter prediction parameter may not be carried in the syntax element, and the decoding end 30 may directly use the default prediction mode for decoding. It is appreciated that the inter prediction unit 244 may be used to perform any combination of inter prediction techniques.

The intra prediction unit 254 is used to obtain, for example, a picture block 203 (current picture block) that receives the same picture and one or more previously reconstructed blocks, for example, reconstructed neighboring blocks, for intra estimation. For example, encoder 20 may be configured to select an intra-prediction mode from a plurality of (predetermined) intra-prediction modes.

Embodiments of encoder 20 may be used to select an intra-prediction mode based on optimization criteria, such as based on a minimum residual (e.g., the intra-prediction mode that provides a prediction block 255 most similar to current picture block 203) or minimum rate distortion.

The intra prediction unit 254 is further adapted to determine an intra prediction block 255 based on intra prediction parameters like the selected intra prediction mode. In any case, after the intra-prediction mode for the block is selected, the intra-prediction unit 254 is also configured to provide the intra-prediction parameters, i.e., information indicating the selected intra-prediction mode for the block, to the entropy encoding unit 270. In one example, intra-prediction unit 254 may be used to perform any combination of intra-prediction techniques.

Specifically, the intra-prediction unit 254 may transmit a syntax element including an intra-prediction parameter (such as indication information of an intra-prediction mode selected for prediction of the current image block after traversing a plurality of intra-prediction modes) to the entropy encoding unit 270. In a possible application scenario, if there is only one intra prediction mode, the intra prediction parameter may not be carried in the syntax element, and the decoding end 30 may directly use the default prediction mode for decoding.

The entropy encoding unit 270 is configured to apply an entropy encoding algorithm or scheme (e.g., a variable length coding (variable length coding, VLC) scheme, a Context Adaptive VLC (CAVLC) scheme, an arithmetic coding scheme, a context adaptive binary arithmetic coding (context adaptive binary arithmetic coding, CABAC), a syntax-based context-based binary arithmetic coding (SBAC), a probability interval partitioning entropy (probability interval partitioning entropy, PIPE) coding, or other entropy encoding methods or techniques) to one or all of the quantized residual coefficients 209, inter-prediction parameters, intra-prediction parameters, and/or loop filter parameters (or not) to obtain encoded picture data 21 that may be output by the output 272 in the form of, for example, an encoded bitstream 21. The encoded bitstream may be transmitted to video decoder 30 or archived for later transmission or retrieval by video decoder 30. Entropy encoding unit 270 may also be used to entropy encode other syntax elements of the current video slice being encoded.

Other structural variations of video encoder 20 may be used to encode the video stream. For example, the non-transform based encoder 20 may directly quantize the residual signal without a transform processing unit 206 for certain blocks or frames. In another embodiment, encoder 20 may have quantization unit 208 and inverse quantization unit 210 combined into a single unit.

In particular, in embodiments of the present application, encoder 20 may be used to implement the video encoding process described in embodiments below.

It should be understood that the video encoder in the present application may include only a part of the modules in the video encoder 20, for example, the video encoder in the present application may include an image decoding unit and a dividing unit. Wherein the image decoding unit may be composed of one or more units of an entropy decoding unit, a prediction unit, an inverse transform unit, and an inverse quantization unit.

In addition, other structural variations of video encoder 20 may be used to encode the video stream. For example, for some image blocks or image frames, video encoder 20 may directly quantize the residual signal without processing by transform processing unit 206, and accordingly without processing by inverse transform processing unit 212; alternatively, for some image blocks or image frames, video encoder 20 does not generate residual data and accordingly does not need to be processed by transform processing unit 206, quantization unit 208, inverse quantization unit 210, and inverse transform processing unit 212; alternatively, video encoder 20 may store the reconstructed image block directly as a reference block without processing via filter 220; alternatively, quantization unit 208 and inverse quantization unit 210 in video encoder 20 may be combined together. The loop filter 220 is optional, and in the case of lossless compression encoding, the transform processing unit 206, quantization unit 208, inverse quantization unit 210, and inverse transform processing unit 212 are optional. It should be appreciated that inter-prediction unit 244 and intra-prediction unit 254 may be selectively enabled depending on the different application scenarios.

Referring to fig. 3, fig. 3 shows a schematic/conceptual block diagram of an example of a decoder 30 for implementing an embodiment of the present application. Video decoder 30 is operative to receive encoded picture data (e.g., encoded bitstream) 21, e.g., encoded by encoder 20, to obtain decoded picture 231. During the decoding process, video decoder 30 receives video data, such as an encoded video bitstream representing picture blocks of an encoded video slice and associated syntax elements, from video encoder 20.

In the example of fig. 3, decoder 30 includes entropy decoding unit 304, inverse quantization unit 310, inverse transform processing unit 312, reconstruction unit 314 (e.g., summer 314), buffer 316, loop filter 320, decoded picture buffer 330, and prediction processing unit 360. The prediction processing unit 360 may include an inter prediction unit 344, an intra prediction unit 354, and a mode selection unit 362. In some examples, video decoder 30 may perform a decoding pass that is substantially reciprocal to the encoding pass described with reference to video encoder 20 of fig. 2.

Entropy decoding unit 304 is used to perform entropy decoding on encoded picture data 21 to obtain, for example, quantized coefficients 309 and/or decoded encoding parameters (not shown in fig. 3), e.g., any or all of inter-prediction, intra-prediction parameters, loop filter parameters, and/or other syntax elements (decoded). Entropy decoding unit 304 is further configured to forward inter-prediction parameters, intra-prediction parameters, and/or other syntax elements to prediction processing unit 360. Video decoder 30 may receive syntax elements at the video stripe level and/or the video block level.

Inverse quantization unit 310 may be functionally identical to inverse quantization unit 110, inverse transform processing unit 312 may be functionally identical to inverse transform processing unit 212, reconstruction unit 314 may be functionally identical to reconstruction unit 214, buffer 316 may be functionally identical to buffer 216, loop filter 320 may be functionally identical to loop filter 220, and decoded picture buffer 330 may be functionally identical to decoded picture buffer 230.

The prediction processing unit 360 may include an inter prediction unit 344 and an intra prediction unit 354, where the inter prediction unit 344 may be similar in function to the inter prediction unit 244 and the intra prediction unit 354 may be similar in function to the intra prediction unit 254. The prediction processing unit 360 is typically used to perform block prediction and/or to obtain a prediction block 365 from the encoded data 21, as well as to receive or obtain prediction related parameters and/or information about the selected prediction mode (explicitly or implicitly) from, for example, the entropy decoding unit 304.

When a video slice is encoded as an intra-coded (I) slice, the intra-prediction unit 354 of the prediction processing unit 360 is used to generate a prediction block 365 for a picture block of the current video slice based on the signaled intra-prediction mode and data from a previously decoded block of the current frame or picture. When a video frame is encoded as an inter-coded (i.e., B or P) slice, an inter-prediction unit 344 (e.g., a motion compensation unit) of prediction processing unit 360 is used to generate a prediction block 365 for a video block of the current video slice based on the motion vector and other syntax elements received from entropy decoding unit 304. For inter prediction, a prediction block may be generated from one reference picture within one reference picture list. Video decoder 30 may construct a reference frame list based on the reference pictures stored in DPB 330 using default construction techniques: list 0 and list 1.

The prediction processing unit 360 is configured to determine prediction information for a video block of a current video slice by parsing the motion vector and other syntax elements, and generate a prediction block for the current video block being decoded using the prediction information. In an example of the present application, prediction processing unit 360 uses some syntax elements received to determine a prediction mode (e.g., intra or inter prediction) for encoding video blocks of a video slice, an inter prediction slice type (e.g., B slice, P slice, or GPB slice), construction information for one or more of the reference picture lists of the slice, motion vectors for each inter-encoded video block of the slice, inter prediction state for each inter-encoded video block of the slice, and other information to decode video blocks of the current video slice. In another example of the present application, the syntax elements received by video decoder 30 from the bitstream include syntax elements received in one or more of an adaptive parameter set (adaptive parameter set, APS), a sequence parameter set (sequence parameter set, SPS), a picture parameter set (picture parameter set, PPS), or a slice header.

Inverse quantization unit 310 may be used to inverse quantize (i.e., inverse quantize) the quantized transform coefficients provided in the bitstream and decoded by entropy decoding unit 304. The inverse quantization process may include using quantization parameters calculated by video encoder 20 for each video block in a video stripe to determine the degree of quantization that should be applied and likewise the degree of inverse quantization that should be applied.

The inverse transform processing unit 312 is configured to apply an inverse transform (e.g., an inverse DCT, an inverse integer transform, or a conceptually similar inverse transform process) to the transform coefficients in order to generate a residual block in the pixel domain.

A reconstruction unit 314 (e.g., a summer 314) is used to add the inverse transform block 313 (i.e., the reconstructed residual block 313) to the prediction block 365 to obtain a reconstructed block 315 in the sample domain, e.g., by adding sample values of the reconstructed residual block 313 to sample values of the prediction block 365.

Loop filter unit 320 is used (during or after the encoding cycle) to filter reconstructed block 315 to obtain filtered block 321, to smooth pixel transitions or improve video quality. In one example, loop filter unit 320 may be used to perform any combination of the filtering techniques described below. Loop filter unit 320 is intended to represent one or more loop filters, such as a deblocking filter, a sample-adaptive offset (SAO) filter, or other filters, such as a bilateral filter, an adaptive loop filter (adaptive loop filter, ALF), or a sharpening or smoothing filter, or a collaborative filter. Although loop filter unit 320 is shown in fig. 3 as an in-loop filter, in other configurations loop filter unit 320 may be implemented as a post-loop filter.

The decoded video blocks 321 in a given frame or picture are then stored in a decoded picture buffer 330 that stores reference pictures for subsequent motion compensation.

Decoder 30 is for outputting decoded picture 31, e.g., via output 332, for presentation to a user or for viewing by a user.

Other variations of video decoder 30 may be used to decode the compressed bitstream. For example, decoder 30 may generate the output video stream without loop filter unit 320. For example, the non-transform based decoder 30 may directly inverse quantize the residual signal without an inverse transform processing unit 312 for certain blocks or frames. In another embodiment, the video decoder 30 may have an inverse quantization unit 310 and an inverse transform processing unit 312 combined into a single unit.

Specifically, in the present embodiment, the decoder 30 is used to implement the video decoding method described in the later embodiments.

It should be understood that the video encoder in the present application may include only a part of the modules in the video encoder 30, for example, the video encoder in the present application may include a dividing unit and an image encoding unit. Wherein the image encoding unit may be composed of one or more of a prediction unit, a transformation unit, a quantization unit, and an entropy encoding unit.

In addition, other structural variations of video decoder 30 may be used to decode the encoded video bitstream. For example, video decoder 30 may generate an output video stream without processing by filter 320; alternatively, for some image blocks or image frames, the entropy decoding unit 304 of the video decoder 30 does not decode quantized coefficients, and accordingly does not need to be processed by the inverse quantization unit 310 and the inverse transform processing unit 312. Loop filter 320 is optional; and for the case of lossless compression, the inverse quantization unit 310 and the inverse transform processing unit 312 are optional. It should be appreciated that the inter prediction unit and the intra prediction unit may be selectively enabled according to different application scenarios.

It should be understood that, in the encoder 20 and the decoder 30 of the present application, the processing result for a certain link may be further processed and then output to a next link, for example, after the links such as interpolation filtering, motion vector derivation or loop filtering, the processing result of the corresponding link may be further subjected to operations such as clipping (clip) or shifting (shift).

For example, the motion vector of the control point of the current image block derived from the motion vector of the adjacent affine encoded block (the encoded block predicted using the affine motion model may be referred to as an affine encoded block), or the motion vector of the sub-block of the current image block derived may be further processed, which is not limited in this application. For example, the range of motion vectors is constrained to be within a certain bit width. Assuming that the bit width of the allowed motion vector is bitDepth, the range of motion vectors is-2 (bitDepth-1) to 2 (bitDepth-1) -1, where the "∈" sign represents the power. If the bitDepth is 16, the value range is-32768-32767. If the bitDepth is 18, the value range is-131072 ～ 131071.

For another example, the motion vectors (e.g., motion vectors MV of four 4x4 sub-blocks within an 8x8 image block) may also be constrained to take values such that the maximum difference between the integer portions of the four 4x4 sub-blocks MV does not exceed N (e.g., N may take 1 pixel).

Referring to fig. 4, fig. 4 is an illustration of an example of a video coding system 40 including encoder 20 of fig. 2 and/or decoder 30 of fig. 3, according to an example embodiment. Video coding system 40 may implement a combination of the various techniques of the embodiments of the present application. In the illustrated embodiment, video coding system 40 may include an imaging device 41, an encoder 20, a decoder 30 (and/or a video codec implemented by logic circuitry 47 of a processing unit 46), an antenna 42, one or more processors 43, one or more memories 44, and/or a display device 45.

As shown in fig. 4, the imaging device 41, the antenna 42, the processing unit 46, the logic circuit 47, the encoder 20, the decoder 30, the processor 43, the memory 44, and/or the display device 45 can communicate with each other. As discussed, although video coding system 40 is depicted with encoder 20 and decoder 30, in different examples, video coding system 40 may include only encoder 20 or only decoder 30.

In some examples, antenna 42 may be used to transmit or receive an encoded bitstream of video data. Additionally, in some examples, display device 45 may be used to present video data. In some examples, logic 47 may be implemented by processing unit 46. The processing unit 46 may comprise application-specific integrated circuit (ASIC) logic, a graphics processor, a general-purpose processor, or the like. The video coding system 40 may also include an optional processor 43, which optional processor 43 may similarly include application-specific integrated circuit (ASIC) logic, a graphics processor, a general purpose processor, or the like. In some examples, logic 47 may be implemented in hardware, such as video encoding dedicated hardware, processor 43 may be implemented in general purpose software, an operating system, or the like. In addition, the memory 44 may be any type of memory, such as volatile memory (e.g., static random access memory (static random access memory, SRAM), dynamic random access memory (dynamic random access memory, DRAM), etc.) or non-volatile memory (e.g., flash memory, etc.), and the like. In a non-limiting example, the memory 44 may be implemented by an overspeed cache. In some examples, logic circuitry 47 may access memory 44 (e.g., for implementing an image buffer). In other examples, logic 47 and/or processing unit 46 may include memory (e.g., a cache, etc.) for implementing an image buffer, etc.

In some examples, encoder 20 implemented by logic circuitry may include an image buffer (e.g., implemented by processing unit 46 or memory 44) and a graphics processing unit (e.g., implemented by processing unit 46). The graphics processing unit may be communicatively coupled to the image buffer. The graphics processing unit may include encoder 20 implemented by logic circuitry 47 to implement the various modules discussed with reference to fig. 2 and/or any other encoder system or subsystem described herein. Logic circuitry may be used to perform various operations discussed herein.

In some examples, decoder 30 may be implemented in a similar manner by logic circuit 47 to implement the various modules discussed with reference to decoder 30 of fig. 3 and/or any other decoder system or subsystem described herein. In some examples, decoder 30 implemented by logic circuitry may include an image buffer (implemented by processing unit 2820 or memory 44) and a graphics processing unit (e.g., implemented by processing unit 46). The graphics processing unit may be communicatively coupled to the image buffer. The graphics processing unit may include decoder 30 implemented by logic circuit 47 to implement the various modules discussed with reference to fig. 3 and/or any other decoder system or subsystem described herein.

In some examples, antenna 42 may be used to receive an encoded bitstream of video data. As discussed, the encoded bitstream may include data related to the encoded video frame, indicators, index values, mode selection data, etc., discussed herein, such as data related to the encoded partitions (e.g., transform coefficients or quantized transform coefficients, optional indicators (as discussed), and/or data defining the encoded partitions). Video coding system 40 may also include a decoder 30 coupled to antenna 42 and used to decode the encoded bitstream. The display device 45 is used to present video frames.

It should be understood that for the example described with reference to encoder 20 in the embodiments of the present application, decoder 30 may be used to perform the reverse process. Regarding signaling syntax elements, decoder 30 may be configured to receive and parse such syntax elements and decode the associated video data accordingly. In some examples, encoder 20 may entropy encode the syntax elements into an encoded video bitstream. In such examples, decoder 30 may parse such syntax elements and decode the relevant video data accordingly.

Referring to fig. 5, fig. 5 is a schematic structural diagram of a video decoding apparatus 400 (e.g., a video encoding apparatus 400 or a video decoding apparatus 400) provided in an embodiment of the present application. The video coding apparatus 400 is adapted to implement the embodiments described herein. In one embodiment, video coding device 400 may be a video decoder (e.g., decoder 30 of fig. 3) or a video encoder (e.g., encoder 20 of fig. 2). In another embodiment, video coding apparatus 400 may be one or more of the components described above in decoder 30 of fig. 3 or encoder 20 of fig. 2.

The video coding apparatus 400 includes: an ingress 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 egress port 450 for transmitting data, and a memory 460 for storing data. The video decoding apparatus 400 may further include a photoelectric conversion component and an electro-optical (EO) component coupled to the inlet port 410, the receiver unit 420, the transmitter unit 440, and the outlet port 450 for the outlet or inlet of optical or electrical signals.

The processor 430 is implemented in hardware and software. Processor 430 may be implemented as one or more CPU chips, cores (e.g., multi-core processors), FPGAs, ASICs, and DSPs. Processor 430 is in communication with inlet port 410, receiver unit 420, transmitter unit 440, outlet port 450, and memory 460. The processor 430 includes a coding module 470 (e.g., an encoding module 470 or a decoding module 470). The encoding/decoding module 470 implements the embodiments disclosed herein to implement the encoding/decoding methods of the embodiments of the present application. For example, the encoding/decoding module 470 implements, processes, or provides various encoding operations. Thus, substantial improvements are provided to the functionality of the video coding device 400 by the encoding/decoding module 470 and affect the transition of the video coding device 400 to different states. Alternatively, the encoding/decoding module 470 is implemented in instructions stored in the memory 460 and executed by the processor 430.

Memory 460 includes one or more disks, tape drives, and solid state drives, and may be used as an overflow data storage device for storing programs when selectively executing such programs, as well as storing instructions and data read during program execution. Memory 460 may be volatile and/or nonvolatile and may be Read Only Memory (ROM), random Access Memory (RAM), random access memory (TCAM) and/or Static Random Access Memory (SRAM).

Referring to fig. 6, fig. 6 is a simplified block diagram of an apparatus 500 that may be used as either or both of the source device 12 and the destination device 14 in fig. 1, according to an example embodiment. The apparatus 500 may implement the encoding method or the decoding method of the embodiments of the present application. In other words, fig. 6 is a schematic block diagram of one implementation of an encoding device or decoding device (simply referred to as decoding device 500) of an embodiment of the present application. The decoding device 500 may include, among other things, a processor 510, a memory 530, and a bus system 550. The processor is connected with the memory through the bus system, the memory is used for storing instructions, and the processor is used for executing the instructions stored by the memory. The memory of the decoding device stores program codes, and the processor can call the program codes stored in the memory to perform various video encoding or decoding methods described herein, particularly various new image block dividing methods. To avoid repetition, a detailed description is not provided herein.

In the present embodiment, the processor 510 may be a central processing unit (central processing unit, CPU), and the processor 510 may also be other general purpose processors, digital Signal Processors (DSPs), application Specific Integrated Circuits (ASICs), off-the-shelf programmable gate arrays (FPGAs) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general purpose processor may be a microprocessor or the processor may be any conventional processor or the like.

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 535, which application 535 includes at least one program that allows processor 510 to perform the video encoding or decoding methods described herein. For example, applications 535 may include applications 1 through N, which further include video encoding or decoding applications (simply video coding applications) that perform the video encoding or decoding methods described herein.

The bus system 550 may include a power bus, a control bus, a status signal bus, and the like in addition to a data bus. For clarity of illustration, the various buses are labeled in the figure as bus system 550.

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 touch sensitive display that incorporates a display with a touch sensitive unit operable to sense touch input. A display 570 may be connected to processor 510 via bus 550.

In order to better understand the image prediction process in the encoding method and decoding method according to the embodiments of the present application, some related concepts and basic contents of inter prediction will be described in detail below.

Inter prediction refers to searching for a matching reference block for a current image block in a current image in a reconstructed image, and taking the pixel value of a pixel point in the reference block as a predicted value of the pixel point in the current image block (this process is called motion estimation (Motion estimation, ME)).

Motion estimation is to try multiple reference blocks in a reference picture for a current picture block, then use rate-distortion optimization (rate-distortion optimization, RDO) or other methods to finally determine one or two reference blocks (two reference blocks are needed for bi-prediction) from the multiple reference blocks, and use the reference blocks to inter-predict the current picture block.

The motion information of the current image block includes indication information of a prediction direction (usually forward prediction, backward prediction or bi-prediction), one or two Motion Vectors (MVs) pointing to the reference block, and indication information of an image where the reference block is located (usually referred to as reference frame index (reference index)).

Forward prediction refers to the selection of a reference picture from a forward reference picture set for a current picture block to obtain a reference block. Backward prediction refers to the selection of a reference picture from a backward reference picture set for a current picture block to obtain a reference block. Bi-prediction refers to the selection of one reference picture from each of the forward and backward reference picture sets to obtain a reference block. When the bi-prediction method is used, the current coding block has two reference blocks, each of which needs a motion vector and a reference frame index to indicate, and then a predicted value of a pixel point in the current image block is determined according to the pixel values of the pixel points in the two reference blocks.

In HEVC, there are two inter prediction modes, AMVP mode and merge mode, respectively.

In the AMVP mode, a coded block (denoted as a neighboring block) adjacent to a current coding block in space domain or time domain is traversed, a candidate motion vector list is constructed according to motion information of each neighboring block, then an optimal motion vector is determined from the candidate motion vector list through rate-distortion cost, and candidate motion information with the minimum rate-distortion cost is used as a motion vector predicted value (motion vector predictor, MVP) of the current coding block.

The positions of the adjacent blocks and the traversing sequence thereof are predefined. The rate distortion cost may be calculated according to formula (1), where J is a rate distortion cost (rate-distortion cost), SAD is a sum of absolute errors (sum of absolute differences, SAD) between a pixel prediction value obtained by performing motion estimation using a candidate motion vector prediction value and an original pixel value, R is a code rate, λ is a lagrangian multiplier, and the encoding end transmits an index value of the selected motion vector prediction value in the candidate motion vector list and a reference frame index value to the decoding end. Further, the encoding end may perform motion search in a neighborhood with MVP as the center to obtain an actual motion vector of the current encoding block, and then transfer a difference value (motion vector difference) between the MVP and the actual motion vector to the decoding end.

J＝SAD+λR (1)

In addition, the AMVP mode may be classified into a translation model-based AMVP mode and a non-translation model-based AMVP mode according to a difference in motion model.

In the merge mode, a candidate motion information list is constructed through motion information of coded units adjacent to a current coding unit in a space domain or a time domain, optimal motion information is determined from the candidate motion information list through rate distortion cost to serve as motion information of the current coding unit, and finally an index value (marked as merge index, the same applies below) of the position of the optimal motion information in the candidate motion information list is transmitted to a decoding end.

In the merge mode, the spatial and temporal candidate motion information of the current coding unit may be as shown in fig. 7, where the spatial candidate motion information is from 5 spatially neighboring blocks (A0, A1, B0, B1 and B2), and if a neighboring block is not available or is intra-prediction, the neighboring block is not added to the candidate motion information list.

The time-domain candidate motion information of the current coding unit may be obtained by scaling MVs of corresponding position blocks in the reference frame according to sequence counts (picture order count, POC) of the reference frame and the current frame. And firstly judging whether the block with the position T in the reference frame is available or not when the block with the position T in the reference frame is acquired, and if not, selecting the block with the position C.

When the translation model is adopted for prediction, all pixels in the coding unit adopt the same motion information, and then motion compensation is carried out according to the motion information, so that the predicted value of the pixels of the coding unit is obtained. However, in the real world, there are various kinds of motion, there are many non-translational motion objects, such as rotating objects, roller coasters rotating in different directions, some special actions in fireworks and movies put in, especially moving objects in user generated content (user generated content, UGC) scenes, and coding them, and if the block motion compensation technology based on translational motion model in the current coding standard is adopted, the coding efficiency is greatly affected, so in order to improve the coding effect, a prediction based on non-translational motion model is proposed.

The non-translational motion model prediction refers to that the same motion model is used at a coding end to deduce the motion information of each sub-motion compensation unit in a current coding block, and then motion compensation is carried out according to the motion information of the sub-motion compensation units to obtain a predicted sub-block of each sub-block, so that the prediction efficiency is improved. Common non-translational motion models are 4-parameter affine motion models or 6-parameter affine motion models.

The placeholders may also be referred to as format placeholders, which primarily function as format placeholders, indicating that there is an input or an output at that location. In many scenarios, the pixel values of an image may be represented by placeholders.

Because of the huge data volume, the 3D point cloud data is often required to be converted into 2D plane data as a positioning map layer. As shown in fig. 8, the 3D point cloud data includes three-dimensional coordinates (x, y, z) and reflectivity (R), and when the data is converted into 2D plane data, the (x, y) coordinates of the 3D point cloud data can be directly used as the (x, y) coordinates of the 2D plane data (x and y are equivalent to the positions of the pixels in the picture), the height z in the 3D point cloud data is mapped onto the R channel of the 2D plane data, and the reflectivity R is mapped onto the G channel, so that the conversion from the 3D point cloud data to the 2D plane data is realized.

However, since the positioning map layer covers a large geographical area, the data volume of the positioning map layer is still very large, and thus, how to further reduce the data volume of the positioning map layer is an important issue.

The positioning map layer data includes elevation data, which is elevation data of points in the positioning map layer with respect to a reference plane. In general, the surface of a building or other object represented by elevation data is continuous, and thus, the change in elevation is continuous, and thus, placeholders for elevation data are also generally characterized by continuity (continuous occurrence of '1' or '0'). Fig. 9 shows the duty ratio of the highest two consecutive bits of "11" and "10" of the 12 grid pictures, and the probability of the highest two consecutive bits of "11" in the 12 grid pictures in fig. 9 is found to be above 70% through statistics, that is, the elevation data has the characteristic of continuity. Therefore, according to the characteristic of the continuity of the elevation data, the exclusive OR or the inverse operation can be carried out on the elevation data, and the data volume of the elevation data can be reduced, so that the data volume of the layer data is reduced.

When the pixel value in the image contains the elevation data, the data quantity of the elevation data can be reduced by carrying out exclusive or inverse operation on the elevation data in advance, so that the storage space occupied by the code stream generated during encoding is reduced.

Accordingly, the present application provides an image encoding method and a decoding method, and the decoding method and the encoding method according to the embodiments of the present application are described in detail below, respectively.

Fig. 10 is a schematic flowchart of an image decoding method of an embodiment of the present application. The method shown in fig. 10 may be performed by a decoding apparatus or a decoder.

Fig. 10 shows a main decoding process, where after the decoding end obtains the code stream, the decoding end may decompress the code stream first, and then perform an exclusive-or process or an inverse process, so as to obtain an image block finally.

Specifically, the decoding end may perform exclusive or processing or inverse processing on the image block after obtaining the image block according to the residual block and the prediction block of the image block, so as to obtain the image block finally. The decoding end may also perform exclusive or processing or inverse processing on the residual block of the image block after obtaining the residual block and the prediction block of the image block, to obtain a processed residual block, and then finally obtain the image block according to the processed residual block and the prediction block.

In the application, the encoding end may perform preprocessing (performing inversion processing or exclusive-or processing on pixel values of the image) on the image before performing formal encoding on the image, and then perform encoding to obtain a code stream. Correspondingly, the decoding end can obtain an image through decoding firstly when decoding, and then carries out corresponding processing (inversion processing or exclusive-or processing) on the image to obtain a final image. This processing is described below in conjunction with fig. 11.

As shown in fig. 11, image blocks may be obtained by decoding the code stream (for a specific decoding process, see the decoding related process shown in fig. 3), and then the image blocks may be spliced into an image according to the positions of the image blocks, and then the image may be subjected to an exclusive-or process or an inverse process to obtain a processed image.

In the method shown in fig. 11, an image is obtained by analyzing a code stream, and then the image is processed. That is, the method shown in fig. 11 is to complete the decoding process first and then process the decoded image.

The decoding method according to the embodiment of the present application will be described in detail with reference to fig. 12.

Fig. 12 is a schematic flowchart of an image decoding method of an embodiment of the present application. The method shown in fig. 12 may be performed by a decoding apparatus or a decoder. The method shown in fig. 12 includes steps 1001 to 1005, and steps 1001 to 1005 are described in detail below.

1001. And obtaining a code stream.

The code stream acquired in step 1001 may be a code stream encoded in the encoding method shown in fig. 16 hereinafter.

1002. And obtaining a residual block of the image block according to the code stream.

In step 1002, the residual block of the current image block may be obtained by parsing the code stream, and for a specific parsing process, reference may be made to the decoding related process shown in fig. 3.

1003. And obtaining a prediction block of the image block according to the code stream.

The prediction block of the image block may be obtained by either inter prediction or intra prediction, and is not limited thereto. In addition, the process of acquiring the predicted block of the image block through the code stream in step 1003 may refer to the decoding related process shown in fig. 3.

It should be understood that step 1002 and step 1003 may be performed simultaneously or sequentially, and the sequence of step 1002 and step 1003 is not limited in this application.

1004. And obtaining the image block according to the residual block of the image block and the prediction block of the image block.

In step 1004, the residual block and the prediction block may be superimposed to obtain an image block, and a specific process may refer to a decoding related process shown in fig. 3.

1005. And processing the image block to obtain a processed image block.

It should be understood that, in the decoding method shown in fig. 12, the corresponding image block is decoded by the code stream, and then the image block is processed, and correspondingly, when the image block is encoded, the encoding end corresponding to the method shown in fig. 12 processes the image block, and then encodes the processed image block to generate the code stream.

The above-mentioned processing of the image block in step 1005 may specifically be performing an exclusive-or processing or an inverse processing on the pixel value of the image block, and these two processes are described in detail below.

The first way is: and carrying out inverse processing on the pixel values of the image block.

In the first manner, after processing an image block, the pixel value of the processed image block and the pixel value of the image block may satisfy the following relationship:

the value of the ith bit in the N bits of the pixel value of the image block is opposite to the value of the ith bit in the N bits of the pixel value of the processed image block.

The N bits of the pixel value of the image block are located at the same position as the N bits of the pixel value of the processed image block, the N bits of the pixel value of the image block are located behind and adjacent to the first bit of the pixel value of the image block, the first bit is the bit with the value of 1 and the highest bit in the pixel value of the image block, i and N are positive integers, i is less than or equal to N, and N is less than or equal to M.

For example, as shown in table 1, the pixel value of the image block is 0X4F (0100 1111), the pixel value of the processed image block is 0X70 (0111 0000), and the last 6 bits (00 1111) in the pixel value of the image block are the same as the last 6 bits (11 0000) in the pixel value of the processed image block, from the 5 th bit to the 0 th bit. The last 6 bits of the pixel value of the image block are located after and adjacent to the first bit, which is the bit of the pixel value of the image block having a value of 1 and the highest number of bits. The last 6 bits in the pixel values of the processed image block are respectively opposite to the last 6 bits in the pixel values of the image block. When the pixel value of the image block is processed, the processed image block can be obtained by inverting the value of the last 6 bits of the image block. It should be understood that in the example shown in table 1, the encoding end converts the pixel value of the image block from 0X70 to 0X40, and the decoding end converts the pixel value of the image block from 0X40 to 0X70, so as to obtain the pixel value of the original image.

TABLE 1

The second way is: and performing exclusive OR processing on the pixel values of the image blocks.

In the second manner, after processing the image block, the pixel value of the processed image block and the pixel value of the image block may satisfy the following relationship:

the value of the 1 st bit in the N bits of the pixel value of the processed image block is opposite to the value of the 1 st bit in the N bits of the image block;

the value of the (i+1) th bit in the N bits of the processed image block is the result of exclusive-or processing of the (i+1) th bit in the N bits of the image block and the (i) th bit in the N bits of the processed image block.

Wherein the N bits of the pixel value of the image block are located after and adjacent to the first bit of the pixel value of the image block, which is the bit of the pixel value of the image block having the value 1 and the highest number of bits, or the N bits of the pixel value of the image block are located after and adjacent to the highest bit of the pixel value of the image block.

In addition, N bits of the pixel value of the image block are the same as N bits of the pixel value of the processed image block, the bit number of the ith bit is higher than the bit number of the (i+1) th bit, i and N are positive integers, i is less than or equal to N, and N is less than M.

It should be understood that, in the second manner, the value of the 1 st bit of the N bits of the pixel value of the image block may be inverted, and the value of the i+1 th bit of the N bits of the image block may be xored with the i bit of the N bits of the processed image block to obtain the value of the i+1 th bit of the N bits of the processed image block.

For example, as shown in table 2, the pixel value of the image block is 0X48 (0100 1000), the pixel value of the processed image block is 0X70 (0111 0000), and the last 6 bits (00 1000) in the pixel value of the image block are the same as the last 6 bits (11 0000) in the pixel value of the processed image block, and all the positions are from the 5 th bit to the 0 th bit. The last 6 bits of the pixel value of the image block are located after and adjacent to the first bit, which is the bit of the pixel value of the image block having a value of 1 and the highest number of bits.

As can be seen from table 2, the value of the 1 st bit of the last 6 bits of the processed image block is opposite to the value of the 1 st bit of the last 6 bits of the image block.

As another example, as can be seen from table 2, the value of the (i+1) th bit in the last 6 bits of the processed image block is the result of exclusive-or processing the (i+1) th bit in the last 6 bits of the image block with the (i) th bit in the last 6 bits of the processed image block, i is equal to or less than N. It will be appreciated that of the last 6 bits of the image block described above, the number of bits of the i+1th bit is lower than the number of bits of the i-th bit.

Specifically, as shown in table 2, the value of the 2 nd bit (value of 1) in the last 6 bits of the processed image block is the result of exclusive-or processing of the value of the 2 nd bit (value of 0) in the last 6 bits of the image block and the value of the 1 st bit (value of 1) in the last 6 bits of the processed image block.

The value of the 3 rd bit (value of 0) in the last 6 bits of the processed image block is the result of exclusive-or processing of the 3 rd bit (value of 1) in the last 6 bits of the image block and the 2 nd bit (value of 1) in the last 6 bits of the processed image block.

It should be understood that in the example shown in table 2, the encoding end converts the pixel value of the image block from 0X70 to 0X48, and the decoding end converts the pixel value of the image block from 0X48 to 0X70, so as to obtain the pixel value of the original image.

TABLE 2

In this embodiment of the present application, the encoding end performs the exclusive-or processing or the inverse processing on the pixel value of the image block, so that the data size of the image block can be reduced when the pixel value of the image block includes a continuous placeholder, so that the code stream generated by encoding occupies less storage space, and the decoding end performs the (inverse or exclusive-or) processing on the decoded image block, so that the image block processed by the encoding end (exclusive-or processing or inverse processing) can be restored, and further the final image block is obtained.

Optionally, the acquiring the residual block of the image block in the step 1002 specifically includes: and performing inverse transformation, inverse quantization and entropy decoding on the code stream to obtain the residual block.

Optionally, the acquiring the residual block of the image block in the step 1002 specifically includes: and performing entropy decoding treatment on the code stream to obtain the residual block.

Optionally, the code stream is obtained by encoding a positioning layer.

Optionally, the pixel values of the positioning map layer include rasterized elevation data.

It should be understood that, at the encoding end corresponding to the decoding method shown in fig. 12, the image block is processed first, and then the processed image block is encoded to generate a code stream.

In practice, the encoding end may process the image block to obtain a residual block of the image block, then process the residual block of the image block to obtain a residual block of the image block, and then encode the residual block of the image block to generate a code stream. In this case, the decoding end may process the residual block after decoding to obtain the residual block during decoding, and then combine the processed residual block with the prediction block of the image block to obtain the image block, and this decoding manner will be described in detail below.

Fig. 13 is a schematic flowchart of an image decoding method of an embodiment of the present application. The method shown in fig. 13 may be performed by a decoding apparatus or a decoder. The method shown in fig. 13 includes steps 2001 to 2004, and steps 2001 to 2004 are described in detail below.

2001. And obtaining a code stream.

The code stream acquired in step 2001 may be a code stream encoded in the encoding method shown in fig. 20 hereinafter.

2002. And obtaining a residual block of the image block according to the code stream.

In step 2002, the residual block of the current image block may be obtained by parsing the code stream, and the specific parsing process may refer to the relevant content of fig. 3.

2003. And obtaining a prediction block of the image block according to the code stream.

In step 2003, the prediction block of the image block may be obtained by either an inter prediction method or an intra prediction method, which is not limited herein. The process of acquiring the predicted block of the image block in step 2003 can be referred to as a decoding-related process shown in fig. 3.

It should be understood that the above steps 2002 and 2003 may be performed simultaneously or sequentially, and the sequence of steps 2002 and 2003 is not limited in this application.

2004. And processing the residual block to obtain a processed residual block.

The above-mentioned sub-processing of the residual block in step 2004 may specifically be exclusive-or processing or inverse processing of the pixel value of the residual block, and these two processes are described in detail below.

Third mode: and carrying out inverse processing on pixel values of the residual block.

In a third manner, after processing the residual block, the pixel value of the processed image block and the pixel value of the image block may satisfy the following relationship:

The N bits of the pixel value of the residual block are positioned behind and adjacent to the first bit of the pixel value of the residual block, wherein the first bit is a bit with the highest bit number and the value of 1 in the pixel value of the residual block, i and N are positive integers, i is less than or equal to N, and N is less than M.

The process of inverting the pixel values of the residual block in the third mode is similar to the process of inverting the pixel values of the image block in the first mode, except that the pixel values of the residual block are processed in the third mode and the pixel values of the image block are processed in the first mode. The specific processing of the pixel values of the residual block in the third way may be found in the description of the correlation in the first way and will not be described in detail here.

Fourth mode: and performing exclusive OR processing on the pixel values of the residual block.

In a fourth manner, after processing the residual block, the pixel value of the processed image block and the pixel value of the image block may satisfy the following relationship:

The exclusive-or processing of the pixel values of the residual block in the fourth way is similar to the exclusive-or processing of the pixel values of the image block in the second way, except that the pixel values of the residual block are processed in the fourth way and the pixel values of the image block are processed in the second way. The detailed processing of the pixel values of the residual block in the fourth mode can be seen from the related description of the second mode, and will not be described in detail here.

2005. And obtaining an image block according to the processed residual error block and the prediction block.

In step 2005, the processed residual block and the prediction block may be superimposed to obtain an image block, and a specific process may be referred to as a decoding related process shown in fig. 3.

Optionally, the obtaining the residual block of the image block in step 2002 specifically includes: and performing inverse transformation, inverse quantization and entropy decoding on the code stream to obtain the residual block.

Optionally, the obtaining the residual block of the image block in step 2002 specifically includes: and performing entropy decoding treatment on the code stream to obtain the residual block.

The above decoding method for performing only entropy decoding corresponds to lossless encoding, and this encoding method can ensure the display effect of the image.

Optionally, the code stream is obtained by encoding a positioning layer.

The image decoding method of the embodiment of the present application is described in detail above with reference to fig. 12 and 13, and the image encoding method of the embodiment of the present application is described below with reference to fig. 14 to 26.

Fig. 14 is a schematic flowchart of an image encoding method of an embodiment of the present application. The method shown in fig. 14 may be performed by an encoding apparatus or an encoder.

Fig. 14 shows a main process of encoding, where the encoding end may first perform an exclusive-or inverse processing on the image block, and then perform encoding compression on the image block after the exclusive-or inverse processing, so as to obtain a code stream.

Specifically, the encoding end may perform the exclusive-or processing or the inverse processing on the image block, and then encode the image block after the exclusive-or processing or the inverse processing to obtain the code stream. The coding end can also predict the image block to obtain a predicted block and a residual block of the image block, then perform exclusive-or inverse processing on the residual block, and finally code the residual block after exclusive-or inverse processing to obtain a code stream.

In the application, the encoding end may perform preprocessing (performing inversion processing or exclusive-or processing on pixel values of the image) on the image before performing formal encoding on the image, and then perform encoding to obtain a code stream. This is described below in conjunction with fig. 16.

As shown in fig. 15, prior to the main encoding, the pixel values of the image are subjected to exclusive or inversion processing to obtain a processed image, and then the image is encoded. When encoding an image, the image may be divided into image blocks, and then the obtained image blocks are encoded (for a specific encoding process, refer to a related encoding process shown in fig. 3), to obtain a code stream.

In the method shown in fig. 15, the image is preprocessed and then encoded.

The encoding method according to the embodiment of the present application will be described in detail with reference to fig. 16.

Fig. 16 is a schematic flowchart of an image encoding method of an embodiment of the present application. The method shown in fig. 16 may be performed by an encoding apparatus or an encoder. The method shown in fig. 16 includes steps 3001 to 3004, and steps 3001 to 3004 are described in detail below.

3001. An image block is acquired.

Optionally, the image blocks are from a localization map layer. The localization map layer is 2D plane data that may be mapped from 3D point cloud data. The process of mapping 3D point cloud data to obtain 2D plane data can be seen in fig. 8.

3002. And processing the image block to obtain a processed image block.

The image block may be processed in step 3002 in a number of ways, which are described below.

A fifth mode: and carrying out inverse processing on the pixel values of the image block.

In a fifth mode, after processing an image block, the pixel value of the processed image block and the pixel value of the image block may satisfy the following relationship:

The fifth mode is the same as the processing mode for the pixel values of the image block in the first mode, and the description of the first mode is also applicable to the fifth mode, and the fifth mode is not described in detail here in order to avoid unnecessary repetition.

In the embodiment of the application, the pixel value of the image block is subjected to the inverse processing, so that the data size of the pixel value of the image block can be reduced, and the size of the generated code stream is further reduced.

Further, the corresponding coding performance of N is different under different values, and when N takes a specific value, the corresponding coding performance is optimal, and the reduced bits are the largest.

As shown in fig. 17, the pixel values of the image block correspond to 8 bits in total, when the N bits in the pixel values of the image block are subjected to the inversion processing, a certain number of bits can be reduced, and when n=3, the degree of reduction of the number of bits is maximum, and the corresponding coding performance is also optimal.

In the actual encoding process, the value of N may be set according to the test result or experience, for example, when the pixel value of the image block corresponds to 8 bits altogether, n=3 or n=4 may be selected, so that better encoding performance can be obtained, and the data amount of the image block can be reduced as much as possible.

A sixth mode: and performing exclusive OR processing on the pixel values of the image blocks.

In the sixth mode, after processing the image block, the pixel value of the processed image block and the pixel value of the image block may satisfy the following relationship:

The value of the 1 st bit in the N bits of the processed image block is opposite to the value of the 1 st bit in the N bits of the image block; the value of the (i+1) th bit in the N bits of the processed image block is the result of exclusive-or processing of the (i+1) th bit in the N bits of the image block and the (i) th bit in the N bits of the processed image block.

The sixth mode is the same as the processing mode for the pixel values of the image block in the second mode, and the description of the second mode is also applicable to the sixth mode, and the sixth mode is not described in detail here in order to avoid unnecessary repetition.

In the embodiment of the application, the pixel values of the image block are subjected to exclusive or processing, so that the data size of the pixel values of the image block can be reduced, and the size of the generated code stream is further reduced.

Further, the corresponding coding performance is different at different values of N, and in general, the larger the value of N is, the better the corresponding coding performance is, and the more bits are reduced.

As shown in fig. 18, the pixel values of the image block correspond to 8 bits in total, when the exclusive or processing is performed on N bits in the pixel values of the image block, a certain number of bits can be reduced, and when n=6, the degree of reduction of the number of bits is maximum, and the corresponding coding performance is also optimal.

In the actual encoding process, the value of N may be set according to the test result or experience, for example, when the pixel value of the image block corresponds to 8 bits altogether, a larger value may be set for N, for example, N is set to 5 or 6, so that better encoding performance can be obtained, and the data volume of the image block is reduced as much as possible.

In step 3002, when the pixel values of the image block are processed, the pixel values of the image block may be inverted or the pixel values of the image block may be exclusive-or processed, as shown in fig. 19.

Step 3002 may be specifically subdivided into two implementations, step 3002a and step 3000b in fig. 19. Wherein, step 3002a and step 3002b are respectively:

3002a, performing inversion processing on pixel values of the image block to obtain a processed image block.

3002b, performing exclusive or processing on the pixel values of the image block to obtain a processed image block.

Wherein step 3002a corresponds to the fifth manner above and step 3002b corresponds to the sixth manner above.

It should be understood that in fig. 19, after step 3001 is performed, either step 3002a or step 3002b may be performed, and then step 3003 may be performed.

3003. And predicting the processed image block to obtain a residual block.

In step 3003, the processed image block may be predicted to obtain a predicted block of the processed image block, and then, based on the processed image block and the predicted block of the processed image block, a residual block of the processed image block may be obtained (the processed image block may be subjected to a difference with the predicted block of the processed image block to obtain the residual block).

3004. And encoding the residual block to obtain a code stream.

In step 3004, the residual block may be encoded using either lossless encoding or lossy encoding.

When lossless coding is adopted, the residual block can be subjected to transformation, quantization and entropy coding to obtain a coded code stream.

By encoding the residual block in a lossless encoding mode, image distortion can be avoided as much as possible, and the final display effect of the image is ensured.

When lossy coding is adopted, entropy coding processing can be directly carried out on the residual block, and a coded code stream is obtained.

By encoding the residual block by means of lossy encoding, the memory space occupied by the resulting code stream can be reduced.

In the embodiment of the application, the encoding end performs exclusive-or processing or inverse processing on the pixel values of the image blocks, so that the data volume of the image blocks can be reduced under the condition that the pixel values of the image blocks contain continuous placeholders, and the code stream generated by encoding occupies less storage space.

The process of predicting the processed image block in step 3003 to obtain a residual block and encoding the residual block to obtain a code stream may refer to the related encoding process shown in fig. 2.

In the encoding process shown in fig. 16, an image block is first subjected to exclusive-or processing or inverse processing, and then the processed image block is encoded to obtain a code stream.

In practice, in the encoding process, the image block may be predicted first, so as to obtain a residual block of the image block, then the residual block is subjected to exclusive-or processing or inverse processing, and then the processed residual block is encoded, so as to obtain a code stream. This coding scheme is described in detail below in conjunction with fig. 20.

Fig. 20 is a schematic flowchart of an image encoding method of an embodiment of the present application. The method shown in fig. 20 may be performed by an encoding apparatus or an encoder. The method shown in fig. 20 includes steps 4001 to 4004, and steps 4001 to 4004 are described in detail below.

4001. An image block is acquired.

Optionally, the image block is from a positioning map layer, and the positioning map layer is 2D plane data mapped by 3D point cloud data. The process of mapping 3D point cloud data to obtain 2D plane data can be seen in fig. 8.

4002. And predicting the image block to obtain a residual block of the image block.

In step 4002, an image block may be predicted to obtain a predicted block of the image block, and then a residual block of the image block may be obtained according to the image block and the predicted block of the image block (the image block may be subjected to a difference with the predicted block of the image block to obtain the residual block).

4003. And processing the residual block to obtain a processed residual block.

The image block may be processed in step 4003 in a number of ways, which are described below.

A seventh mode: and carrying out inverse processing on pixel values of the residual block.

In a seventh aspect, after processing the residual block, the pixel value of the processed image block and the pixel value of the image block may satisfy the following relationship:

The seventh mode is the same as the processing mode for the pixel values of the image block in the third mode, and a detailed description of the seventh mode is omitted to avoid unnecessary repetition.

Eighth mode: and performing exclusive OR processing on the pixel values of the residual block.

In an eighth mode, after processing the residual block, the pixel value of the processed image block and the pixel value of the image block may satisfy the following relationship:

The eighth mode is the same as the fourth mode in processing pixel values of an image block, and is not described in detail here to avoid unnecessary repetition.

In step 4003, when the pixel values of the residual block are processed, the pixel values of the residual block may be inverted or exclusive-or processed, as shown in fig. 21.

Step 4003 can be specifically subdivided into two implementations, step 4003a and step 4003b in fig. 21. Step 4003a and step 4003b are respectively:

4003a, performing inverse processing on pixel values of the residual block to obtain a processed residual block.

4003b, performing exclusive or processing on the pixel values of the residual block to obtain a processed residual block.

Step 4003a corresponds to the seventh mode hereinabove, and step 4003b corresponds to the eighth mode hereinabove.

It is to be understood that in fig. 21, after step 4002 is performed, either step 4003a or step 4003b may be performed, and then step 4004 may be performed.

4004. And coding the processed residual block to obtain a code stream.

In step 4004, the processed residual block may be encoded using either lossless encoding or lossy encoding.

When lossless coding is adopted, the processed residual block can be subjected to transformation, quantization and entropy coding to obtain a coded code stream.

The processed residual block is encoded in a lossless encoding mode, so that image distortion can be avoided as much as possible, and the final display effect of the image is ensured.

When lossy coding is adopted, entropy coding processing can be directly carried out on the processed residual block, and a coded code stream is obtained.

The method can reduce the memory space occupied by the finally obtained code stream by adopting a lossy coding mode to code the processed residual block.

The specific implementation of step 4003 and step 4004 described above may be found in the relevant process of encoding shown in fig. 2 above.

In the embodiment of the present application, the encoding end performs the exclusive-or processing or the inverse processing on the pixel value of the residual block, so that the data size of the residual block can be reduced when the pixel value of the residual block includes a continuous placeholder, and the code stream generated by encoding occupies less storage space.

In order to better describe the embodiments of the present application, a process of locating elevation data of a map layer is described below by taking fig. 22 and 23 as an example.

FIG. 22 is a schematic flow chart of processing elevation data of a positioning map layer. The process shown in fig. 22 includes steps 5001 and 5002, and steps 5001 and 5002 are described below.

5001. Searching for a character '1' from the highest bit of the elevation data, and determining that the character '1' appears at the ith bit of the elevation data for the first time;

5002. from the ith character of the elevation data, exclusive or processing is sequentially performed with the characters of the adjacent high order until the least significant bit (least significant bit, LSB).

For example, the height data is 0X70 (0111 0000), the character '1' is found at the 6 th bit of the height data starting from the 7 th bit (the most significant bit) of the height data, and then the current bit is xored with the character of the adjacent higher bit in turn starting from the 5 th bit of the height data, and the xored operation of the height data is described below with reference to table 3.

As shown in table 3, the 5 th to 0 th bits of the elevation data are 11 0000, the adjacent high-order characters are 11 1000, and 00 1000 is obtained by exclusive-or processing. Since the 7 th bit and the 6 th bit of the elevation data are not xored, the 7 th bit and the 6 th bit of the elevation data after the xored are unchanged, and finally the elevation data after the xored is 0X48 (0100 1000).

TABLE 3 Table 3

In the method, the numerical value of the elevation data can be reduced by performing exclusive OR operation on part of bits in the elevation data, and then the size of the layer data where the elevation data are located can be reduced.

Specifically, the probability of continuously appearing "11" in the elevation data is large, and by exclusive-or processing the elevation data, "11" continuously appearing in the elevation data can be reduced, so that the numerical value of the elevation data is reduced, which is equivalent to the pixel value of the image being reduced.

In order to further simplify the processing procedure of the elevation data, the procedure of searching for the character '1' can be omitted, the most significant bit (most significant bit, MSB) of the elevation data is reserved, and the exclusive OR processing is directly performed from the next highest bit of the elevation data. The following detailed description refers to the accompanying drawings.

FIG. 23 is a schematic flow chart of processing elevation data locating a map layer. The process shown in fig. 23 includes steps 6001 and 6002, and steps 6001 and 6002 are described below.

6001. The MSB of the elevation data is kept unchanged;

6002. the current bit is exclusive-ored with the adjacent upper bit in sequence from the bit following the MSB of the elevation data until the LSB.

It should be understood that in the actual execution, step 6001 may not be executed, and step 6002 may be executed directly.

Here again, taking the example of 0X70 (0111 0000) as the elevation data, the MSB of the elevation data is the 7 th bit, which needs to be reserved, and the 6 th bit to the 0 th bit of the elevation data need to be exclusive-ored. As shown in table 4, the 6 th bit to the 0 th bit of the elevation data are 111 0000, the adjacent high-order characters are 011 1000, and the result 100 1000 is obtained by the exclusive-or processing. Since the MSB of the elevation data is not exclusive-ored, the elevation data obtained by exclusive-ored is 0100 1000.

TABLE 4 Table 4

In the method, the complexity of performing the exclusive or operation can be simplified by performing the exclusive or operation from the MSB of the elevation data to the next highest order of the elevation data.

Since the probability of the continuous occurrence of "11" is relatively high in the elevation data, the data amount of the elevation data can be reduced by performing the inverting operation on the elevation data.

Therefore, in the present application, in addition to the reduction of the data amount of the elevation data by exclusive-or processing of the elevation data, the data amount of the elevation data can be reduced by inverting the elevation data.

FIG. 24 is a schematic flow chart of processing elevation data locating a map layer. The process shown in fig. 24 includes steps 7001 and 7002, and the steps 7001 and 7002 are described below.

7001. Searching for a character '1' from the highest bit of the elevation data, and determining that the character '1' appears at the ith bit of the elevation data for the first time;

7002. the character of the elevation data is inverted from the ith character of the elevation data until the least significant bit (least significant bit, LSB).

For example, taking the height data 0X70 (0111 0000) as an example, starting from the 7 th bit (the highest bit) of the height data, the character '1' is found at the 6 th bit of the height data, and then the 5 th bit to the 0 th bit of the height data are inverted to obtain 0X4F (0100 1111).

By performing the inverse processing on the elevation data, the data amount of the elevation data (converted from 0X70 to 0X 4F) can be reduced.

It should be understood that, when the inversion processing is performed in the above step 7002, the inversion processing may be performed from the LSB to the i character, and the sequence of the inversion processing is not limited in this application.

In order to better explain the effect of the encoding method of the embodiment of the present application, the effect of the image encoding method of the embodiment of the present application will be described below with reference to specific test results.

Table 5 shows the amount of data after encoding portable network graphics (portable network graphics, PNG) format pictures using high efficiency video coding-screen content coding (high efficiency video coding-screen content coding, HEVC-SCC) and PNG format pictures using HEVC-SCC and XOR operations. As shown in table 5, the test pictures contain 12 PNG format pictures (1 a.png to 1e.png and 2a.png to 2g.png respectively), and as can be seen from table 5, the data size after HEVC-SCC encoding is smaller than that of PNG format pictures, and the data size of the finally obtained code stream is smaller when xor processing is further adopted in the HEVC-SCC encoding process.

Specifically, by statistics of the test effects of the 12 test pictures shown in table 5, the data amount of the code stream obtained after the pictures are encoded by using HEVC-SCC is reduced by 16.3% relative to the original data amount of the pictures, and the data amount of the code stream obtained by using the encoding mode of HEVC-scc+xor is reduced by 16.8% relative to the data amount of the pictures. Therefore, performing exclusive or processing in the encoding process can reduce the data amount of the picture.

TABLE 5

The following describes in detail the procedure of the encoding method of the embodiment of the present application with reference to fig. 25 and 26.

Fig. 25 is a schematic flowchart of an image encoding method of an embodiment of the present application. The method shown in fig. 25 may be performed by an encoding apparatus or an encoder. The method shown in fig. 25 includes steps 8001 to 8006, and steps 8001 to 8006 are described below.

8001. And obtaining a picture.

8002. The picture is divided into image blocks.

A picture may also be referred to herein as an image, and to facilitate encoding of the picture, the picture is typically divided into a plurality of image blocks, and each image block is then encoded.

8003. And carrying out inversion or exclusive-or processing on the pixel values of the image block to obtain the image block subjected to inversion or exclusive-or processing.

The specific process of inverting the pixel values of the image block in step 8003 may be referred to as related description in the fifth mode, and the specific process of performing the exclusive-or processing on the pixel values of the image block in step 8003 may be referred to as related description in the sixth mode.

8004. And predicting the image block subjected to the inversion or exclusive-or processing to obtain a prediction block.

In step 8004, the prediction block of the processed image block may be obtained by either inter prediction or intra prediction.

8005. The prediction block is transformed and quantized.

8006. And carrying out entropy coding on the transformed and quantized result to obtain a coded code stream.

The encoding process in steps 8004 to 8006 can be referred to as the related process of encoding shown in fig. 2.

Fig. 26 is a schematic flowchart of an image encoding method of an embodiment of the present application. The method shown in fig. 26 may be performed by an encoding apparatus or an encoder. The method shown in fig. 26 includes steps 9001 to 9006, and steps 9001 to 9006 are described below.

9001. And obtaining a picture.

9002. The picture is divided into image blocks.

The above-mentioned picture may also be referred to as an image, and in order to facilitate encoding of the picture, the picture is generally divided into a plurality of image blocks, and then each image block is encoded.

9003. And predicting the image block to obtain a residual block.

In step 9003, the image block may be predicted to obtain a predicted block of the image block, and then the residual block of the image block is obtained according to the image block and the predicted block of the image block. Specifically, an image block may be differenced with a residual block of the image block to obtain the residual block of the image block.

The specific procedure of the prediction in step 9003 described above can be referred to as a correlation procedure of the prediction shown in fig. 2.

9004. And carrying out inversion or exclusive-or processing on the pixel values of the residual block.

The specific process of inverting the pixel values of the residual block in step 9004 may be referred to as related description in the seventh mode, and the specific process of performing the exclusive-or processing on the pixel values of the residual block in step 9004 may be referred to as related description in the eighth mode.

9005. And transforming and quantizing the prediction block subjected to the negation or the exclusive OR processing.

9006. And carrying out entropy coding on the transformed and quantized result to obtain a coded code stream.

The specific process of encoding in step 9005 and step 9006 described above can be referred to as the related process of encoding shown in fig. 2.

Among the methods shown in fig. 25 and 26, the method shown in fig. 25 performs the inverse or exclusive-or processing on the pixel values of the image block before encoding the image block. The method shown in fig. 26 is to perform the inversion or exclusive-or processing on the pixel value of the residual block after obtaining the residual block of the current image block, which is equivalent to performing the inversion or exclusive-or processing on the pixel value in the encoding process. In the application, the pixel value is subjected to inverse processing or exclusive-or processing before or after encoding, so that the data volume can be reduced, and the finally obtained code stream occupies less storage space.

The image decoding method and the encoding method according to the embodiments of the present application are described in detail above with reference to the accompanying drawings, and the image decoding apparatus and the image encoding apparatus according to the embodiments of the present application are described below with reference to fig. 27 to 30. It should be understood that the image decoding apparatus in fig. 27 to 30 is capable of performing the image decoding method of the embodiment of the present application, and the image encoding apparatus in fig. 27 to 30 is capable of performing the image encoding method of the embodiment of the present application. In order to avoid unnecessary repetition, the repeated description is appropriately omitted below when describing the image decoding apparatus and the image encoding apparatus of the embodiment of the present application.

Fig. 27 is a schematic block diagram of an image decoding apparatus of an embodiment of the present application.

The image decoding apparatus 10000 shown in fig. 27 includes an acquisition unit 10001 and a processing unit 10002. The image decoding apparatus 10000 can perform the image decoding method of the embodiment of the present application, and in particular, the image decoding apparatus 10000 can perform the image decoding method shown in fig. 12 and 13.

Fig. 28 is a schematic block diagram of an image encoding apparatus of an embodiment of the present application.

The image encoding apparatus 11000 shown in fig. 28 includes an acquisition unit 11001 and a processing unit 11002. The image encoding apparatus 11000 may perform the image encoding method of the embodiment of the present application, and in particular, the image encoding apparatus 11000 may perform the steps in the methods shown in fig. 16 and fig. 19 to 26.

Fig. 29 is a schematic hardware configuration of an image decoding apparatus according to an embodiment of the present application.

The image decoding apparatus 12000 shown in fig. 29 (the image decoding apparatus 12000 may be a computer device in particular) includes a memory 12001, a memory 12002, a communication interface 12003, and a bus 12004. The memory 12001, the memory 12002, and the communication interface 12003 are connected to each other by a bus 12004.

The memory 12001 may be a Read Only Memory (ROM), a static storage device, a dynamic storage device, or a random access memory (random access memory, RAM). The memory 12001 may store a program, and when the program stored in the memory 12001 is executed by the memory 12002, the memory 12002 is used to perform the respective steps of the image decoding method of the embodiment of the present application.

The memory 12002 may be implemented with a general-purpose central processing unit (central processing unit, CPU), microprocessor, application specific integrated circuit (application specific integrated circuit, ASIC), graphics processor (graphics processing unit, GPU) or one or more integrated circuits for executing associated programs to implement the image decoding methods of the method embodiments of the present application.

The memory 12002 may also be an integrated circuit chip with signal processing capabilities. In implementation, the steps of the image decoding method of the present application may be completed by an integrated logic circuit of hardware or an instruction in the form of software in the memory 12002.

The memory 12002 may also be a general purpose processor, digital signal processor (digital signal processing, DSP), application Specific Integrated Circuit (ASIC), off-the-shelf programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic device, discrete hardware components. The disclosed methods, steps, and logic blocks in the embodiments of the present application may be implemented or performed.

A general purpose processor may be a microprocessor or the processor may be any conventional processor or the like. The steps of a method disclosed in connection with the embodiments of the present application may be embodied directly in hardware, in a decoded processor, or in a combination of hardware and software modules in a decoded processor. The software modules may be located in a random access memory, flash memory, read only memory, programmable read only memory, or electrically erasable programmable memory, registers, etc. as well known in the art. The storage medium is located in the memory 12001, and the processor 12002 reads information in the memory 12001, and in combination with hardware thereof, performs functions required to be performed by units included in the image decoding apparatus, or performs an image decoding method of an embodiment of the method of the present application.

The communication interface 12003 enables communication between the image decoding apparatus 12000 and other devices or communication networks using a transceiving apparatus such as, but not limited to, a transceiver. For example, information of the neural network to be constructed and training data required in constructing the neural network may be acquired through the communication interface 12003.

The bus 12004 may include pathways to transfer information between various components of the image decoding device 12000 (e.g., the memory 12001, the memory 12002, the communication interface 12003).

The acquisition unit 10001 and the processing unit 10002 in the image decoding apparatus 10000 correspond to the processor 12002 in the image decoding apparatus 12000.

Fig. 30 is a schematic hardware configuration diagram of an image encoding apparatus according to an embodiment of the present application. The image encoding apparatus 13000 (the image decoding apparatus 13000 may be a computer device in particular) shown in fig. 30 includes a memory 13001, a processor 13002, a communication interface 13003, and a bus 13004. The memory 13001, the processor 13002, and the communication interface 13003 are connected to each other by a bus 13004.

The above definitions and explanations of the respective modules in the image decoding apparatus 12000 also apply to the image encoding apparatus 13000, and will not be described in detail here.

The above-described memory 13001 may be used to store a program, and the processor 13002 is used to execute the program stored in the memory 13001, and when the program stored in the memory 13001 is executed, the processor 13002 is used to execute the respective steps of the image encoding method of the embodiment of the present application.

In addition, when the image encoding device 13000 encodes an image, the image to be encoded may be acquired through a communication interface, and then the acquired image to be encoded is encoded to obtain encoded data, and the encoded data may be transmitted to the decoding apparatus through the communication interface 13003.

When the image encoding device 13000 decodes an image, the image can be acquired through the communication interface, and then the acquired image is decoded to obtain an image to be displayed.

The acquisition unit 11001 and the processing unit 11002 in the image encoding device 11000 correspond to the processor 13002 in the image encoding device 13000.

Those of ordinary skill in the art will appreciate that the various illustrative elements and algorithm steps described in connection with the embodiments disclosed herein may be implemented as electronic hardware, or combinations of computer software and electronic hardware. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the solution. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present application.

It will be clear to those skilled in the art that, for convenience and brevity of description, specific working procedures of the above-described systems, apparatuses and units may refer to corresponding procedures in the foregoing method embodiments, and are not repeated herein.

In the several embodiments provided in this application, it should be understood that the disclosed systems, devices, and methods may be implemented in other manners. For example, the apparatus embodiments described above are merely illustrative, e.g., the division of the units is merely a logical function division, and there may be additional divisions when actually implemented, e.g., multiple units or components may be combined or integrated into another system, or some features may be omitted or not performed. Alternatively, the coupling or direct coupling or communication connection shown or discussed with each other may be an indirect coupling or communication connection via some interfaces, devices or units, which may be in electrical, mechanical or other form.

The units described as separate units may or may not be physically separate, and units shown as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

In addition, each functional unit in each embodiment of the present application may be integrated in one processing unit, or each unit may exist alone physically, or two or more units may be integrated in one unit.

The functions, if implemented in the form of software functional units and sold or used as a stand-alone product, may be stored in a computer-readable storage medium. Based on such understanding, the technical solution of the present application may be embodied essentially or in a part contributing to the prior art or in a part of the technical solution, in the form of a software product stored in a storage medium, including several instructions for causing a computer device (which may be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the methods described in the embodiments of the present application. And the aforementioned storage medium includes: a U-disk, a removable hard disk, a read-only memory (ROM), a random access memory (random access memory, RAM), a magnetic disk, or an optical disk, or other various media capable of storing program codes.

The foregoing is merely specific embodiments of the present application, but the scope of the present application is not limited thereto, and any person skilled in the art can easily think about changes or substitutions within the technical scope of the present application, and the changes and substitutions are intended to be covered by the scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims

1. An image decoding method, comprising:

acquiring a code stream;

according to the code stream, obtaining a residual block of an image block and a prediction block of the image block;

obtaining the image block according to the residual block of the image block and the prediction block of the image block, wherein the pixel value of the image block is represented by M bits, the value of each bit is 0 or 1, and M is an integer greater than 1;

processing the image block to obtain a processed image block;

wherein the value of the ith bit in the N bits of the pixel value of the image block is opposite to the value of the ith bit in the N bits of the pixel value of the processed image block, the N bits of the pixel value of the image block are the same as the positions of the N bits of the pixel value of the processed image block,

n bits of the pixel value of the image block are located behind and adjacent to a first bit of the pixel value of the image block, wherein the first bit is a bit with a value of 1 and the highest bit number in the pixel value of the image block, i and N are positive integers, i is less than or equal to N, and N is less than M.

2. The method of claim 1, wherein obtaining a residual block of an image block from the code stream comprises:

And performing inverse transformation, inverse quantization and entropy decoding on the code stream to obtain the residual block.

3. The method of claim 1, wherein the obtaining a residual block of an image block from the code stream comprises:

and performing entropy decoding processing on the code stream to obtain the residual block.

4. A method according to any of claims 1-3, wherein the code stream is encoded with a positioning bit layer.

5. The method of claim 4, wherein the locating the pixel values of the map layer comprises rasterized elevation data.

6. The method of any one of claims 1-5, wherein M has a value of any one of 8, 10, and 12.

7. An image decoding method, comprising:

acquiring a code stream;

according to the code stream, obtaining a residual block of an image block and a prediction block of the image block, wherein the pixel value of the residual block is represented by M bits, the value of each bit is 0 or 1, and M is an integer greater than 1;

processing the residual block to obtain a processed residual block;

wherein the value of the ith bit in the N bits of the pixel value of the residual block is opposite to the value of the ith bit in the N bits of the pixel value of the processed residual block, the N bits of the pixel value of the residual block are the same as the positions of the N bits of the pixel value of the processed residual block,

N bits of the pixel value of the residual block are positioned behind and adjacent to a first bit of the pixel value of the residual block, wherein the first bit is a bit with a value of 1 and the highest bit number in the pixel value of the residual block, i and N are positive integers, i is less than or equal to N, and N is less than M;

8. The method of claim 7, wherein obtaining a residual block of an image block from the code stream comprises:

9. The method of claim 7, wherein the obtaining the residual block of the image block from the code stream comprises:

10. The method according to any of claims 7-9, wherein the code stream is encoded with a positioning bit layer.

11. The method of claim 10, wherein the locating the pixel values of the map layer comprises rasterized elevation data.

12. The method of any one of claims 7-11, wherein M has a value of any one of 8, 10 and 12.

13. An image decoding method, comprising:

acquiring a code stream;

processing the image block to obtain a processed image block,

wherein the value of the 1 st bit in the N bits of the processed image block is opposite to the value of the 1 st bit in the N bits of the image block, the value of the i+1 th bit in the N bits of the processed image block is the result of exclusive OR processing of the value of the i+1 th bit in the N bits of the image block and the i th bit in the N bits of the processed image block,

the N bits of the pixel value of the image block are located after and adjacent to a first bit of the pixel value of the image block, which is a bit of the pixel value of the image block having a value of 1 and the highest number of bits, or the N bits of the pixel value of the image block are located after and adjacent to a highest bit of the pixel value of the image block,

N bits of the pixel value of the image block are the same as N bits of the pixel value of the processed image block, the bit number of the ith bit is higher than the bit number of the (i+1) th bit, i and N are positive integers, i is less than or equal to N, and N is less than M.

14. The method of claim 13, wherein obtaining a residual block of an image block from the code stream comprises:

15. The method of claim 13, wherein the obtaining the residual block of the image block from the code stream comprises:

16. The method according to any of claims 13-15, wherein the code stream is encoded with a positioning bit layer.

17. The method of claim 16, wherein the locating the pixel values of the map layer comprises rasterized elevation data.

18. The method of any one of claims 13-17, wherein M has a value of any one of 8, 10 and 12.

19. An image decoding method, comprising:

Acquiring a code stream;

processing the residual block to obtain a processed residual block,

wherein the value of the 1 st bit in the N bits of the processed residual block is opposite to the value of the 1 st bit in the N bits of the residual block, the value of the i+1 th bit in the N bits of the processed residual block is the result of exclusive OR processing of the value of the i+1 th bit in the N bits of the residual block and the i th bit in the N bits of the processed residual block,

the N bits of the pixel value of the residual block are located after and adjacent to a first bit of the pixel value of the residual block, which is a bit having a value of 1 and a highest number of bits in the pixel value of the residual block, or the N bits of the pixel value of the residual block are located after and adjacent to a highest number of bits of the pixel value of the residual block,

20. The method of claim 19, wherein obtaining a residual block of an image block from the code stream comprises:

21. The method of claim 19, wherein the obtaining the residual block of the image block from the code stream comprises:

22. The method of any of claims 19-21, wherein the code stream is encoded with a positioning bit layer.

23. The method of claim 22, wherein the locating the pixel values of the map layer comprises rasterized elevation data.

24. The method of any one of claims 19-23, wherein M has a value of any one of 8, 10, and 12.

25. An image encoding method, comprising:

obtaining an image block, wherein the pixel value of the image block is represented by M bits, the value of each bit is 0 or 1, and M is an integer greater than 1;

processing the image block to obtain a processed image block;

n bits of the pixel value of the image block are positioned behind and adjacent to a first bit of the pixel value of the image block, wherein the first bit is a bit with a value of 1 and the highest bit number in the pixel value of the image block, i and N are positive integers, i is less than or equal to N, and N is less than M;

predicting the processed image block to obtain a residual block;

and encoding the residual block to obtain a code stream.

26. The method of claim 25, wherein encoding the residual block to obtain a code stream comprises:

And carrying out transformation, quantization and entropy coding on the residual block to obtain a coded code stream.

27. The method of claim 25, wherein encoding the residual block to obtain a code stream comprises:

and performing entropy coding treatment on the residual block to obtain a coded code stream.

28. The method of any of claims 25-27, wherein the tiles are from a localization map layer.

29. The method of claim 28, wherein the locating the pixel values of the map layer comprises rasterized elevation data.

30. The method of any one of claims 25-29, wherein M has a value of any one of 8, 10 and 12.

31. An image encoding method, comprising:

acquiring an image block;

predicting the image block to obtain a residual block of the image block, wherein the pixel value of the residual block is represented by M bits, the value of each bit is 0 or 1, and M is an integer greater than 1;

processing the residual block to obtain a processed residual block;

and encoding the processed residual block to obtain a code stream.

32. The method of claim 31, wherein encoding the residual block to obtain a code stream comprises:

33. The method of claim 31, wherein encoding the residual block to obtain a code stream comprises:

34. The method of any of claims 31-33, wherein the tiles are from a localization map layer.

35. The method of claim 34, wherein the locating the pixel values of the map layer comprises rasterized elevation data.

36. The method of any one of claims 31-35, wherein M has a value of any one of 8, 10 and 12.

37. An image encoding method, comprising:

processing the image block to obtain a processed image block;

n bits of the pixel value of the image block are the same as the N bits of the pixel value of the processed image block, the bit number of the ith bit is higher than the bit number of the (i+1) th bit, i and N are positive integers, i is less than or equal to N, and N is less than M;

Predicting the processed image block to obtain a residual block;

and encoding the residual block to obtain a code stream.

38. The method of claim 37, wherein encoding the residual block to obtain a code stream comprises:

39. The method of claim 37, wherein encoding the residual block to obtain a code stream comprises:

40. The method of any of claims 37-39, wherein the tiles are from a localization map.

41. The method of claim 40, wherein locating pixel values of a map layer comprises rasterized elevation data.

42. The method of any one of claims 37-41, wherein M has a value of any one of 8, 10, and 12.

43. An image encoding method, comprising:

acquiring an image block;

Processing the residual block to obtain a processed residual block;

wherein the value of the ith bit in the N bits of the pixel value of the residual block is opposite to the value of the ith bit in the N bits of the pixel value of the processed residual block, the value of the (i+1) th bit in the N bits of the processed residual block is the result of exclusive OR processing of the value of the (i+1) th bit in the N bits of the residual block and the ith bit in the N bits of the processed residual block,

And encoding the processed residual block to obtain a code stream.

44. The method of claim 43, wherein encoding the residual block to obtain a code stream comprises:

45. The method of claim 43, wherein encoding the residual block to obtain a code stream comprises:

46. The method of any of claims 43-45, wherein the tiles are from a localization map.

47. The method of claim 46, wherein locating pixel values of a map layer comprises rasterized elevation data.

48. The method of any one of claims 43-47, wherein M has a value of any one of 8, 10, and 12.

49. An image encoding method, comprising:

obtaining an image, wherein the pixel value of the image is represented by M bits, the value of each bit is 0 or 1, and M is an integer greater than 1;

processing the image to obtain a processed image;

Wherein the value of the ith bit in the N bits of the pixel value of the image is opposite to the value of the ith bit in the N bits of the pixel value of the processed image, the N bits of the pixel value of the image are the same as the positions of the N bits of the pixel value of the processed image,

n bits of the pixel value of the image are positioned behind and adjacent to a first bit of the pixel value of the image, wherein the first bit is a bit with a value of 1 and the highest bit number in the pixel value of the image, i and N are positive integers, i is less than or equal to N, and N is less than M;

and encoding the processed image to obtain a code stream.

50. An image encoding method, comprising:

processing the image to obtain a processed image;

wherein the value of the 1 st bit in the N bits of the processed image is opposite to the value of the 1 st bit in the N bits of the image, the value of the (i+1) th bit in the N bits of the processed image is the result of exclusive OR processing of the value of the (i+1) th bit in the N bits of the image and the (i) th bit in the N bits of the processed image,

The N bits of the pixel value of the image are located after and adjacent to a first bit of the pixel value of the image, the first bit being a bit of the pixel value of the image having a value of 1 and the highest number of bits, or the N bits of the pixel value of the image are located after and adjacent to a highest bit of the pixel value of the image,

and encoding the processed image to obtain a code stream.

51. An image decoding device, characterized in that it comprises means for performing the method according to any of claims 1-24.

52. An image encoding device, characterized in that it comprises means for performing the method according to any of claims 25-50.

53. An image decoding apparatus, comprising:

a memory for storing a program;

A processor for executing the memory-stored program, which processor performs the method of any one of claims 1-24 when the memory-stored program is executed by the processor.

54. An image encoding device, comprising:

a memory for storing a program;

a processor for executing the memory-stored program, which processor performs the method of any of claims 25-50 when the memory-stored program is executed by the processor.

55. An electronic device comprising an image decoding apparatus according to claim 53 and/or an image encoding apparatus according to claim 54.

56. A computer readable storage medium, characterized in that the computer readable storage medium stores a computer program executable by a processor, which when executed by the processor performs the method of any of claims 1-24 or 25-50.