WO2016119666A1

WO2016119666A1 - Image coding/decoding method and apparatus

Info

Publication number: WO2016119666A1
Application number: PCT/CN2016/072039
Authority: WO
Inventors: 林涛; 李明; 尚国强; 吴钊
Original assignee: 同济大学; 中兴通讯股份有限公司
Priority date: 2015-01-26
Filing date: 2016-01-25
Publication date: 2016-08-04

Abstract

The present invention provides an image coding/decoding method and apparatus. The coding method comprises: constructing a representative pixel set of a coding block, and determining information needed to construct the representative pixel set; constructing a predicted value of a pixel sample value in the coding block, a generation mode of the predicted value comprising: constructing, according to a reconstructive pixel sample value of an image area outside the coding block and a pixel value of the representative pixel set, the predicted value of the pixel sample value; and coding the information needed to construct the representative pixel set and information needed to construct the predicted value, and writing a video code stream. By means of the technical solution, the problems of longer distance between positions of these reconstructive pixels obtaining the predicted value and a current block, low correlation and low compression efficiency are resolved, the correlation between a predicted value of an image area outside the current block and a current pixel sample value is improved, and the compression efficiency is effectively improved.

Description

Image coding and decoding method and device

Technical field

The present invention relates to the field of image processing, and in particular to an image encoding and decoding method and apparatus.

Background technique

Related technologies, with the development of televisions and monitors entering ultra-high definition (4K) and ultra-high definition (8K) resolutions, as well as the development and popularization of a new generation of cloud computing and information processing modes and platforms with remote desktops as a typical form of expression. The need for video image data compression is also moving toward higher resolution and composite images containing camera-captured images and computer screen images. Ultra-high compression ratio and extremely high-quality data compression of video images have become an indispensable technology.

Taking full advantage of the characteristics of 4K/8K images and computer screen images, the ultra-efficient compression of video images is also the latest international video compression standard (High Efficiency Video Coding, referred to as HEVC) and several other international standards. A major goal of standards and industry standards.

The natural form of a digital video signal of an image is a sequence of images. A frame of image is usually a rectangular area composed of several pixels, and a digital video signal is a sequence of video images composed of tens of frames to thousands of frames of images, sometimes simply referred to as a video sequence or sequence. Encoding a digital video signal encodes a frame by frame image. At any one time, the image of the frame being encoded is referred to as the current encoded image. Similarly, decoding a compressed video stream of a digital video signal (referred to as a bitstream, also referred to as a bitstream) is decoding a stream of one frame by one image. At any one time, the image of the frame being decoded is referred to as the current decoded image. The current encoded image or the currently decoded image is collectively referred to as the current image.

In almost all international standards for video image coding, such as Moving Picture Experts Group (MPEG-1/2/4), H.264/Advanced Video Coding (AVC) and HEVC When encoding one frame of image (and corresponding decoding), dividing one frame of image into sub-images of several blocks of MxM pixels, called a coding block (from a decoding perspective, that is, a decoding block, collectively referred to as a codec block) or "Coding Unit (CU for short)", which uses CU as the basic coding unit to encode sub-pictures one by one. The size of the commonly used M is 4, 8, 16, 32, 64. Therefore, encoding a video image sequence is to encode one CU for each coding unit of each frame image, that is, CU. At any one time, the CU being coded is referred to as the current coded CU. Similarly, decoding the code stream of a video image sequence is also decoding one CU for each CU of each frame image, and finally reconstructing the entire video image sequence. At any one time, the CU being decoded is referred to as the currently decoded CU. The current coding CU or the current decoding CU is collectively referred to as the current CU.

In order to adapt to the difference in image content and properties of each part of a frame of image, the most efficient coding is performed in a targeted manner. The size of each CU in one frame of image can be different, some are 8x8, some are 64x64, and so on. In order to enable seamlessly splicing CUs of different sizes, one frame of image is always divided into "Largest Coding Units (LCUs)" having the same size and having NxN pixels, and then each LCU is further divided into Multiple CUs of a tree structure that are not necessarily the same size. Therefore, the LCU is also referred to as a "Coding Tree Unit (CTU)". E.g, One frame of image is first divided into 64x64 pixel LCUs of the same size (N=64). One of the LCUs is composed of three 32x32 pixel CUs and four 16x16 pixel CUs, so that seven tree-structured CUs form a CTU. The other LCU consists of two 32x32 pixel CUs, three 16x16 pixel CUs, and 20 8x8 pixel CUs. Such 25 CUs in a tree structure constitute another CTU. Encoding one frame of image is to sequentially encode one CU in one CTU. In the HEVC international standard, LCU is synonymous with CTU.

The CU can also be further divided into sub-areas. The sub-area includes, but is not limited to, a prediction unit (Picture Unit, abbreviated as PU), a transform unit (Transform Unit, TU for short), and an asymmetric division (Asymmetric Multi-Processing, AMP for short).

A color pixel usually consists of three components. The two most commonly used pixel color formats are the GBR color format consisting of a green component, a blue component, and a red component, and a YUV color consisting of a luma component and two chromaticity components. The format, commonly known as the YUV color format, actually includes multiple color formats, such as the YCbCr color format. Therefore, when encoding a CU, a CU can be divided into three component planes (G plane, B plane, R plane or Y plane, U plane, V plane), and the three component planes are respectively coded; The three component bundles of one pixel are combined into one 3-tuple, and the CUs composed of these 3-tuples are encoded as a whole. The arrangement of the former pixel and its components is called the planar format of the image (and its CU), and the arrangement of the latter pixel and its components is called the stacked format of the image (and its CU). Format). The GBR color format and the YUV color format of the pixel are both 3-component representation formats of the pixel.

In addition to the 3-component representation format of pixels, another common prior art representation format for pixels is the palette index representation format. In the palette index representation format, the value of a pixel can also be represented by the index of the palette. The palette space stores the value or approximate value of the three components of the pixel that needs to be represented. The address of the palette is called the index of the pixel stored in this address. An index can represent one component of a pixel, and an index can also represent three components of a pixel. The palette can be one or more. In the case of multiple palettes, a complete index is actually composed of the palette number and the index of the numbered palette. The index representation format of a pixel is to represent this pixel with an index. The index representation format of a pixel is also referred to as an indexed color or a pseudo color representation format of a pixel in the prior art, or is often referred to directly as an indexed pixel or a pseudo pixel (pseudo pixel). ) or pixel index or index. Indexes are sometimes referred to as indices. The representation of a pixel in its index representation format is also referred to as indexing or indexing.

Other commonly used prior art pixel representation formats include CMYK presentation formats and grayscale representation formats.

The YUV color format can be subdivided into several seed formats according to whether the chroma component is downsampled: a YUV 4:4:4 pixel color format consisting of 1 Y component, 1 U component, and 1 V component. The left and right adjacent pixels are composed of two Y components, one U component, and one V component in a YUV 4:2:2 pixel color format; four pixels arranged in a left and right adjacent position by 2x2 spatial position are composed of four pixels. YUV4: 2:0 pixel color format consisting of Y component, 1 U component, and 1 V component. A component is generally represented by a number of 8 to 16 bits. The YUV4:2:2 pixel color format and the YUV4:2:0 pixel color format are all downsampled for the YUV4:4:4 pixel color format. A pixel component is also referred to as a pixel sample or simply as a sample.

The most basic element when encoding or decoding can be one pixel, one pixel component, or one pixel index (ie, index pixel). A pixel or a pixel component or an index pixel, which is the most basic element of encoding or decoding, is collectively referred to as a pixel sample, sometimes referred to as a pixel value, or simply as a sample.

In the present patent application, "pixel sample", "pixel value", "sample value", "index pixel", "pixel index" are synonyms, depending on the context, whether it is clear whether "pixel" or "one pixel" The "component" still means "index pixel" or both. If it is not clear from the context, then it means either of the three.

In this patent application, a coded block or a decoded block (collectively referred to as a codec block) is an area composed of a number of pixel values. The shape of the codec block may be a rectangle, a square, a parallelogram, a trapezoid, a polygon, a circle, an ellipse, a string, and the like. A rectangle also includes a rectangle whose width or height is one pixel value that degenerates into a line (ie, a line segment or a line shape). In one frame of image, each codec block may have a different shape and size. In one frame of image, some or all of the codec blocks may overlap each other, or all codec blocks may not overlap each other. A codec block may be composed of "pixels", or may be composed of "components of pixels", or may be composed of "index pixels", or may be composed of a mixture of the three, or any of the three. Mixed composition. From the perspective of video image encoding or decoding, a codec block refers to an area in which encoding or decoding is performed in a frame image, including but not limited to at least one of the following: a maximum coding unit LCU, a coding tree unit CTU, and a coding unit CU. a sub-region of the CU, a prediction unit PU, a transform unit TU, a series of pixels, and a set of pixels.

Video image compression techniques in the related art include: prediction modes (including but not limited to intra prediction and inter prediction) and copying modes (including but not limited to block copying, index copying, microblock copying, strip copying, string copying, and rectangles). Copy, point copy). Here "copy" is the optimal matching pixel that the copy encoder searches for. Therefore, from the perspective of the encoder, the copy mode is also called the matching mode (including but not limited to block matching, index matching, microblock matching, bar matching, string matching, rectangle matching, point matching).

An important feature of the prediction mode and the copy mode is to copy reconstructed pixel samples (including fully reconstructed pixels) from image regions (including directly adjacent and indirectly adjacent) outside the current codec block (referred to as the current block). Samples and/or different degrees of partially reconstructed pixel samples), referred to as predicted values (also referred to as reference values) of pixel samples (referred to as current pixel samples) in the current encoding or decoding, which are to be predicted The value is assigned to the current pixel sample as the reconstructed pixel sample of the current pixel sample.

In the prediction mode and the copy mode in the related art, the predicted value is obtained from the reconstructed pixel samples of the image region outside the current block, and has no direct relationship with the pixel samples of the current block, and thus the positions of the reconstructed pixels exist. The farther the distance from the current block is, the smaller the correlation between each other is and the lower the compression efficiency.

In the related art, the problem that the positions of the reconstructed pixels that obtain the predicted values are far from the current block, the correlation between each other is small, and the compression efficiency is low, there is currently no effective solution.

Summary of the invention

The present invention provides an image encoding and decoding method and apparatus, to at least solve the problem that the positions of the reconstructed pixels obtained by obtaining the predicted values in the related art are far from the current block, and the correlation between each other is small, and the compression efficiency is small. Low problem.

According to an embodiment of the present invention, an image encoding method is provided, including:

Constructing a representative set of pixels of the encoded block, determining information required to construct the representative set of pixels;

And constructing a predicted value of the pixel sample in the coding block, where the predicted value is generated by: reconstructing a pixel sample value of the image region other than the coded block and a pixel value of the representative pixel set, The predicted value of the pixel sample;

The information required to construct the representative set of pixels and the information required to construct the predicted values are encoded and written to the video stream.

In an embodiment of the present invention, the coding block is an coding region of an image, including at least one of: a maximum coding unit LCU, a coding tree unit CTU, a coding unit CU, a sub-region of a CU, a prediction unit PU, a transformation unit TU, pixel string, pixel group, pixel microblock, pixel strip;

The image area other than the coded block includes at least one of: an image area other than the variant of the coded block; an image area formed by the partially coded pixels.

In an embodiment of the invention, the manner in which the predicted value is generated includes one of the following:

Setting the predicted value to a reconstructed pixel sample or the reconstructed pixel sample variant outside the encoded block;

The predicted value is set to a pixel value of the representative pixel set or a pixel value variant of the representative pixel set.

In an embodiment of the invention, the predictive value of the pixel samples in the encoded block is constructed using at least one of the following predefined encoding parameters, including:

Reconstructing the position of the pixel sample in the image;

Constructing the information required to represent the set of pixels;

The number of pixels representing the set of pixels;

a location of a current encoded pixel sample in the encoded block;

a type of a pixel component of the coding block, wherein one pixel component or two of the pixel components of the pixel component select a pixel value of the representative pixel set as a predicted value, the pixel component except the one pixel component Or other pixel components other than the two pixel components, and selecting a pixel value of the reconstructed pixel sample as a predicted value;

The flag of the predicted value.

In an embodiment of the present invention, for the pixel samples in the coding block, the manner in which the predicted value is generated includes:

Calculating a distance between the reconstructed pixel sample and a part or all of the representative pixel samples of the representative pixel set for the reconstructed pixel sample outside the coded block, and setting the optimal representative pixel sample value to The distance satisfies a representative pixel sample value of the first predefined condition;

And if the distance between the optimal representative pixel sample and the reconstructed pixel sample satisfies a second predefined condition, the predicted value is set to a value of the optimal representative pixel sample, if The second predefined condition is not met, the pre- The measured value is set to the value of the reconstructed pixel sample.

In an embodiment of the invention, the distance is an error between pixels, the first predefined condition is that the error is minimal, and the second predefined condition is that the error is less than a first predetermined threshold.

In an embodiment of the present invention, setting the predicted value to the optimal representative pixel sample or the reconstructed pixel sample further includes:

Writing a flag bit identifying the predicted value in the video bitstream; and/or,

A condition parameter constructing the predicted value is written in the video code stream, wherein a pixel sample value satisfying the condition parameter is used as the predicted value.

In an embodiment of the invention, writing a flag indicating the predicted value in the video code stream comprises at least one of the following:

Writing a flag bit for identifying a prediction value selected for the entire sequence into a parameter set of at least one of: a video parameter set VPS, a sequence parameter set SPS, and an image parameter set PPS;

Writing a flag bit for identifying a predicted value selected for the image to the image parameter set PPS and/or the slice header information;

A flag bit for identifying a prediction value selected for the block layer is written to the maximum coding unit LCU and/or the coding unit CU.

In an embodiment of the invention, the condition parameter constructing the predicted value is written in the video code stream, including at least one of the following:

Writing the predetermined condition parameter for the entire sequence to a parameter set of at least one of: a video parameter set VPS, a sequence parameter set SPS, and an image parameter set PPS;

Writing the predetermined condition parameters for the image to the image parameter set PPS and/or the slice header information;

The predetermined condition parameters for the block layer are written to the maximum coding unit LCU layer and/or the coding unit CU layer.

In an embodiment of the invention,

The position of the reconstructed pixel sample outside the encoded block in the image is divided into rows and/or columns adjacent to the encoded block;

And if the reconstructed pixel sample is located in a row and/or column adjacent to the coded block, setting the predicted value to a value of a representative pixel sample of the representative pixel set;

The predicted value is set to a value of the reconstructed pixel sample if the reconstructed pixel sample is located outside of a row and/or column adjacent to the encoded block.

In an embodiment of the invention, the method includes:

The flag of the predicted value is directly obtainable from the video code stream or derived from existing parameters in the video code stream;

The flag of the predicted value is used to indicate that one of the values of the representative pixel samples of the representative pixel set and the reconstructed pixel samples of the coded block are selected as the current encoding in the encoding process. Pixel sample:

The flag bit includes one of the following locations at the location of the video stream:

Video parameter set, sequence parameter set, image parameter set, slice header, CTU header, CU header, coding block header, one, a group or a string of current coding pixel samples in the coding block.

In an embodiment of the present invention, determining the predicted value according to the number of pixels of the representative pixel set includes:

And if the number of pixels is less than a second predetermined threshold, setting the predicted value to a value of a representative pixel sample of the representative pixel set;

If the number of pixels is not less than a second predetermined threshold, the predicted value is set as a value of the reconstructed pixel sample as a predicted value.

According to an embodiment of the present invention, an image decoding method is provided, including:

Parsing a code stream, obtaining a decoding parameter of the decoding block, where the decoding parameter includes at least one of: a parameter required to construct a representative pixel set of the decoding block; and constructing a pixel sample value in the decoding block The parameters required to predict the value;

The representative pixel set is constructed to determine a predicted value, wherein the predicted value is generated by constructing the predicted value according to the reconstructed pixel sample and the pixel value of the representative pixel set.

In an embodiment of the present invention, the decoding block is one decoding region of an image, and includes at least one of: a maximum coding unit LCU, a coding tree unit CTU, a coding unit CU, a sub-region of a CU, a prediction unit PU, and a transformation unit. TU, pixel string, pixel group, pixel microblock, pixel strip;

The image area other than the decoded block includes at least one of: an image area other than the variant of the decoded block; an image area formed by the partially decoded pixel.

Setting the predicted value to a reconstructed pixel sample or the reconstructed pixel sample variant outside the decoded block;

In an embodiment of the present invention, constructing a predicted value of a pixel sample in the decoded block using at least one of the following predefined decoding parameters includes:

Reconstructing the position of the pixel sample in the image;

Constructing the parameters required to represent the set of pixels;

The number of pixels representing the set of pixels;

a location of the currently decoded pixel sample in the decoded block;

a type of a pixel component of the decoding block, wherein one pixel component or two of the pixel components of the pixel component select a pixel value of the representative pixel set as a predicted value, the pixel component except the one pixel component Or other pixel components other than the two pixel components, and selecting a pixel value of the reconstructed pixel sample as a predicted value;

The flag of the predicted value.

In an embodiment of the present invention, for the pixel samples in the decoding block, the manner in which the predicted value is generated includes:

Calculating a distance between the reconstructed pixel sample and a part or all of the representative pixel samples of the representative pixel set for the reconstructed pixel samples outside the decoded block, and setting the optimal representative pixel sample value to The distance satisfies a representative pixel sample value of the first predefined condition;

And if the distance between the optimal representative pixel sample and the reconstructed pixel sample satisfies a second predefined condition, the predicted value is set to a value of the optimal representative pixel sample, if The second predefined condition is not met and the predicted value is set to the value of the reconstructed pixel sample.

In an embodiment of the invention, the method includes: the distance is an error between pixels, the first predefined condition is that the error is the smallest, and the second predefined condition is that the error is less than a first predetermined threshold.

In an embodiment of the present invention, setting the predicted value to the optimal representative pixel sample or the reconstructed pixel sample includes:

Parsing a flag bit in the code stream, setting the predicted value to a value indicated by the flag bit; and/or

A condition parameter in the code stream is parsed, and the predicted value is set to a pixel sample that satisfies the condition parameter.

In an embodiment of the invention, parsing the flag bits in the code stream comprises at least one of the following:

The parameter set for parsing the flag bit used to identify the prediction value selected for the sequence includes at least one of the following: a video parameter set VPS, a sequence parameter set SPS, and an image parameter set PPS;

Parsing an image parameter set PPS and/or strip header information of a flag bit for identifying a predicted value selected for the image;

A maximum coding unit LCU layer and/or a coding unit CU layer in which the flag bits for identifying the prediction values selected for the block layer are located are parsed.

In an embodiment of the invention, parsing the predetermined condition parameters in the code stream comprises at least one of the following:

Parsing a parameter set for the predetermined condition parameter of the sequence, the parameter set comprising at least one of the following: a video parameter set VPS, a sequence parameter set SPS, and an image parameter set PPS;

Parsing an image parameter set PPS and/or strip header information for the predetermined condition parameter of the image;

A maximum coding unit LCU layer and/or a coding unit CU layer in which the predetermined condition parameter for the block layer is located is parsed.

In an embodiment of the invention, the method includes:

The position of the reconstructed pixel samples outside the decoded block in the image is divided into rows and/or columns adjacent to the decoded block:

And if the reconstructed pixel sample is located in a row and/or column adjacent to the decoded block, setting the predicted value to a value of a representative pixel sample of the representative pixel set;

The predicted value is set to a value of the reconstructed pixel sample if the reconstructed pixel sample is located outside of a row and/or column adjacent to the decoded block.

In an embodiment of the invention, the method includes:

Parsing at least one of the data units in the code stream described below, obtaining a flag of the predicted value, the data unit comprising at least one of the following:

Video parameter set, sequence parameter set, image parameter set, slice header, CTU header, CU header, coding block header, one, a group or a string of current coding pixel samples before coding;

Wherein the flag of the predicted value is directly obtained from the code stream or obtained according to an existing parameter in the code stream; the flag bit of the predicted value indicates that the predicted value is set as the representative pixel The value of the set representative pixel sample is also the value of the reconstructed pixel sample outside the decoded block.

In an embodiment of the invention, determining the predicted value according to the number of pixels of the representative pixel set comprises:

If the number of pixels is not less than a second predetermined threshold, the predicted value is set to a value of the reconstructed pixel sample.

According to another embodiment of the present invention, an image encoding apparatus is provided, including:

a first determining module, configured to construct a representative pixel set of the encoded block, and determine information required to construct the representative pixel set;

a second determining module, configured to construct a predicted value of the pixel sample of the encoded block, where the predicted value is generated by: reconstructing a pixel sample according to an image region other than the encoded block and the representative pixel set a pixel value that constructs a predicted value of the pixel sample;

An encoding module is arranged to encode information required to construct the representative set of pixels and information required to construct the predicted value, and write the code stream.

According to another embodiment of the present invention, an image decoding apparatus is provided, including:

a parsing module, configured to parse the code stream, to obtain a decoding parameter of the decoding block, where the decoding parameter includes at least one of the following parameters: constructing a parameter required for the representative pixel set of the decoding block, and constructing a pixel in the decoding block The parameters required for the predicted value of the sample;

a third determining module, configured to construct the representative pixel set, and determine a predicted value, where the predicted value is generated by: constructing the predicted value according to the reconstructed pixel sample and the pixel value of the representative pixel set .

According to the present invention, the representative pixel set of the coding block is constructed, the information required to construct the representative pixel set is determined, and the predicted value of the pixel sample in the coding block is constructed, and the predicted value is generated according to the coding block. Image area reconstruction Pixel samples and pixel values of the representative pixel set, constructing a predicted value of the pixel sample, encoding information required to construct the representative pixel set, and information required to construct the predicted value, and writing the video code stream to solve The distance between the positions of the reconstructed pixels for obtaining the predicted values and the current block is long, the correlation between each other is small, and the compression efficiency is low, and the predicted values of the image regions from outside the current block are improved. When the pixel samples are correlated, the compression efficiency is effectively improved.

DRAWINGS

The drawings described herein are intended to provide a further understanding of the invention, and are intended to be a part of the invention. In the drawing:

1 is a flow chart of an image encoding method according to an embodiment of the present invention;

2 is a flowchart of an image decoding method according to an embodiment of the present invention;

3 is a block diagram 1 of an image encoding apparatus according to an embodiment of the present invention;

4 is a block diagram 2 of an image decoding apparatus according to an embodiment of the present invention;

FIG. 5 is a schematic diagram of obtaining a current pixel prediction value according to a preferred embodiment of the present invention; FIG.

6 is a schematic flow chart of an encoding method according to a preferred embodiment of the present invention;

FIG. 7 is a schematic flowchart diagram of a decoding method provided by a preferred embodiment of the present invention.

detailed description

The invention will be described in detail below with reference to the drawings in conjunction with the embodiments. It should be noted that the embodiments in the present application and the features in the embodiments may be combined with each other without conflict.

It is to be understood that the terms "first", "second" and the like in the specification and claims of the present invention are used to distinguish similar objects, and are not necessarily used to describe a particular order or order.

An image coding method is provided in this embodiment. FIG. 1 is a flowchart of an image coding method according to an embodiment of the present invention. As shown in FIG. 1, the process includes the following steps:

Step S102, constructing a representative pixel set of the coding block, and determining information required to construct the representative pixel set;

Step S104, constructing a predicted value of the pixel sample in the coded block, where the predicted value is generated by: constructing the pixel according to the reconstructed pixel sample value of the image region other than the coded block and the pixel value of the representative pixel set The predicted value of the sample;

Step S106, encoding the information required to construct the representative pixel set and the information required to construct the predicted value, and writing the video code stream.

Through the above steps, constructing a representative pixel set of the coding block, determining information required for constructing the representative pixel set, and constructing a predicted value of the pixel sample value in the coding block, where the predicted value is generated according to the coding block Constructing a reconstructed pixel sample of the image region and a pixel value of the representative pixel set, constructing a predicted value of the pixel sample, and configuring the representative pixel set The information and the information needed to construct the predicted value are encoded and written into the video bitstream, which solves the problem that the position of the reconstructed pixels obtaining the predicted value is far from the current block, and the correlation between the two is small. The problem of low compression efficiency improves the correlation between the predicted value of the image region from outside the current block and the pixel sample value, and effectively improves the compression efficiency.

In this embodiment, the coding block is an coding region of an image, and includes at least one of: a maximum coding unit LCU, a coding tree unit CTU, a coding unit CU, a sub-region of a CU, a prediction unit PU, a transform unit TU, and a pixel. String, pixel group, pixel microblock, pixel strip;

The image area outside the coded block includes at least one of: an image area other than the variant of the coded block; an image area formed by the partially coded pixels.

In this embodiment, the manner in which the predicted value is generated includes one of the following:

Setting the predicted value to a reconstructed pixel sample outside the encoded block or the reconstructed pixel sample variant;

In this embodiment, using at least one of the following predefined encoding parameters, constructing a predicted value of the pixel sample in the encoding block, including:

The position of the reconstructed pixel sample in the image;

Constructing the information required to represent the set of pixels;

The number of pixels representing the set of pixels;

The position of the currently encoded pixel sample in the encoded block;

a type of a pixel component of the coding block, wherein one pixel component of the pixel component or two pixel components select a pixel value of the representative pixel set as a predicted value, the pixel component except the one pixel component or the two pixel components a pixel value other than the pixel component, the pixel value of the reconstructed pixel sample is selected as a predicted value;

The flag of the predicted value.

In this embodiment, for the pixel samples in the coding block, the manner in which the predicted value is generated includes:

Calculating a distance between the reconstructed pixel sample and a part or all of the representative pixel samples of the representative pixel set for the reconstructed pixel sample outside the coded block, and setting the optimal representative pixel sample value to satisfy the distance a representative pixel sample of the first predefined condition;

If the distance between the optimal representative pixel sample and the reconstructed pixel sample satisfies the second predefined condition, the predicted value is set to the value of the optimal representative pixel sample, if the second is not satisfied A predefined condition that sets the predicted value to the value of the reconstructed pixel sample.

In this embodiment, the distance is an error between pixels, the first predefined condition is that the error is the smallest, and the second predefined condition is that the error is less than the first predetermined threshold.

In this embodiment, setting the predicted value to the optimal representative pixel sample or the reconstructed pixel sample includes:

Writing a flag identifying the predicted value in the video stream; and/or,

In this embodiment, writing a flag indicating the predicted value in the video code stream includes at least one of the following:

In this embodiment, the condition parameter for constructing the predicted value is written in the video code stream, including at least one of the following:

Writing the predetermined condition parameter for the image to the image parameter set PPS and/or the strip header information;

The predetermined condition parameter for the block layer is written to the maximum coding unit LCU layer and/or the coding unit CU layer.

In this embodiment, the position of the reconstructed pixel sample outside the coded block in the image is divided into rows and/or columns adjacent to the coded block;

If the reconstructed pixel sample is located outside of the row and/or column adjacent to the coded block, the predicted value is set to the value of the reconstructed pixel sample.

In this embodiment, the flag of the predicted value is directly obtained from the video code stream or obtained according to an existing parameter in the video code stream;

The flag of the predicted value is used to indicate that one of the value of the representative pixel sample value of the representative pixel set and the reconstructed pixel sample value other than the coded block is selected as the current coded pixel sample value in the encoding process. :

The flag bit includes one of the following locations in the video stream:

In this embodiment, determining the predicted value according to the number of pixels of the representative pixel set includes:

If the number of pixels is less than a second predetermined threshold, setting the predicted value to the number of representative pixel samples of the representative pixel set value;

If the number of pixels is not less than the second predetermined threshold, the predicted value is set as the value of the reconstructed pixel sample as a predicted value.

An image decoding method is provided in this embodiment. FIG. 2 is a flowchart of an image decoding method according to an embodiment of the present invention. As shown in FIG. 2, the process includes the following steps:

Step S202, parsing the code stream, and acquiring a decoding parameter of the decoding block, where the decoding parameter includes at least one of the following parameters: a parameter required to construct a representative pixel set of the decoding block; and constructing a pixel sample value in the decoding block. The parameters required to predict the value;

Step S204, constructing the representative pixel set to determine a predicted value, wherein the predicted value is generated by constructing the predicted value according to the reconstructed pixel sample value and the pixel value of the representative pixel set.

Through the above steps, the code stream is parsed to obtain a decoding parameter of the decoding block, where the decoding parameter includes at least one of the following parameters: a parameter required to construct a representative pixel set of the decoding block; and a pixel sample in the decoding block is constructed. a parameter required for predicting a value, constructing the representative pixel set, and determining a predicted value, wherein the predicted value is generated by: constructing the predicted value according to the reconstructed pixel sample and the pixel value of the representative pixel set, and solving The position of the reconstructed pixels that obtain the predicted value is far from the distance between the current blocks, the correlation between each other is small, and the compression efficiency is low, and the predicted value of the image region from outside the current block is improved. The correlation of pixel samples effectively improves the compression efficiency.

In this embodiment, the decoding block is a decoding region of an image, including at least one of: a maximum coding unit LCU, a coding tree unit CTU, a coding unit CU, a sub-region of a CU, a prediction unit PU, a transform unit TU, and a pixel. String, pixel group, pixel microblock, pixel strip;

The image area outside the decoded block includes at least one of: an image area other than the variant of the decoded block; an image area formed by the partially decoded pixel.

Setting the predicted value to a reconstructed pixel sample outside the decoded block or the reconstructed pixel sample variant;

In this embodiment, using at least one of the following predefined decoding parameters, constructing a predicted value of the pixel sample in the decoded block, including:

The position of the reconstructed pixel sample in the image;

Constructing the parameters required to represent the set of pixels;

The number of pixels representing the set of pixels;

The location of the currently decoded pixel sample in the decoded block;

The type of the pixel component of the decoded block, wherein one pixel component of the pixel component or two of the pixel components are selected The pixel value of the representative pixel set is used as a predicted value, and the pixel component selects a pixel value of the reconstructed pixel sample as a predicted value in addition to the one pixel component or other pixel components other than the two pixel components;

The flag of the predicted value.

In this embodiment, for the pixel samples in the decoded block, the generated manner of the predicted value includes:

Calculating a distance between the reconstructed pixel sample and a part or all of the representative pixel samples of the representative pixel set for the reconstructed pixel sample outside the decoded block, and setting the optimal representative pixel sample value to satisfy the distance a representative pixel sample of the first predefined condition;

The condition parameter in the code stream is parsed, and the predicted value is set to a pixel sample that satisfies the condition parameter.

In this embodiment, parsing the flag bit in the code stream includes at least one of the following:

In this embodiment, parsing the predetermined condition parameter in the code stream includes at least one of the following:

In this embodiment, the position of the reconstructed pixel sample outside the decoded block in the image is divided into rows and/or columns adjacent to the decoded block:

If the reconstructed pixel sample is located within a row and/or column adjacent to the decoded block, setting the predicted value to a value of a representative pixel sample of the representative pixel set;

If the reconstructed pixel sample is located outside of the row and/or column adjacent to the decoded block, the predicted value is set to the value of the reconstructed pixel sample.

In this embodiment, at least one of the data units in the code stream is parsed to obtain a flag bit of the predicted value, and the data unit includes at least one of the following:

Wherein, the flag of the predicted value is directly obtained from the code stream or derived according to an existing parameter in the code stream; the flag bit of the predicted value indicates that the predicted value is set as a representative pixel sample of the representative pixel set The value is also the value of the reconstructed pixel sample outside of the decoded block.

If the number of pixels is less than a second predetermined threshold, setting the predicted value to a value of a representative pixel sample of the representative pixel set;

An image coding device is also provided in the embodiment, which is used to implement the above-mentioned embodiments and preferred embodiments, and will not be described again. As used below, the term "module" may implement a combination of software and/or hardware of a predetermined function. Although the apparatus described in the following embodiments is preferably implemented in software, hardware, or a combination of software and hardware, is also possible and contemplated.

FIG. 3 is a block diagram showing the structure of an image encoding apparatus according to an embodiment of the present invention. As shown in FIG. 3, the apparatus includes:

a first determining module 32, configured to construct a representative pixel set of the encoded block, and determine information required to construct the representative pixel set;

The second determining module 34 is connected to the first determining module 32 and configured to construct a predicted value of the pixel sample of the encoded block, where the predicted value is generated by: reconstructing a pixel according to an image region other than the encoded block Constructing a predicted value of the pixel sample value and the pixel value of the representative pixel set;

The encoding module 36 is coupled to the second determining module 34 and configured to encode the information required to construct the representative set of pixels and the information required to construct the predicted value, and write the code stream.

Through the above steps, the first determining module 32 constructs a representative pixel set of the coding block, determines information required to construct the representative pixel set, and the second determining module 34 constructs a predicted value of the pixel sample of the encoded block, and the generation of the predicted value The method includes: constructing a predicted value of the pixel sample according to the reconstructed pixel sample of the image region outside the coded block and the pixel value of the representative pixel set, and the encoding module 36 constructs the information required for the representative pixel set and The information required to construct the predicted value is encoded and written into the code stream, which solves the problem that the positions of the reconstructed pixels for obtaining the predicted value are far from the current block, the correlation between the two is small, and the compression efficiency is low. The problem is that the correlation between the predicted value of the image region from the current block and the pixel sample is improved, and the compression efficiency is effectively improved.

FIG. 4 is a second structural block diagram of an image decoding apparatus according to an embodiment of the present invention. As shown in FIG. 4, the apparatus includes:

The parsing module 42 is configured to parse the code stream, and obtain a decoding parameter of the decoding block, where the decoding parameter includes at least one of the following parameters: constructing a parameter required for the representative pixel set of the decoding block, and constructing a pixel sample in the decoding block The required parameters for the predicted value of the value;

The third determining module 44 is connected to the parsing module 42 and configured to construct the representative pixel set to determine a predicted value, where the predicted value is generated according to the reconstructed pixel sample value and the pixel value of the representative pixel set, The predicted value.

Through the above steps, the parsing module 42 parses the code stream to obtain the decoding parameters of the decoding block, where the decoding parameter includes at least one of the following parameters: constructing parameters required for the representative pixel set of the decoding block, and constructing the pixels in the decoding block. The third determining module 44 constructs the representative pixel set to determine a predicted value, wherein the predicted value is generated according to the reconstructed pixel sample and the pixel value of the representative pixel set. Constructing the predicted value solves the problem that the position of the reconstructed pixels obtained by obtaining the predicted value is far from the current block, the correlation between each other is small, and the compression efficiency is low, and the problem from the current block is improved. The correlation between the predicted value of the image area and the pixel sample value effectively improves the compression efficiency.

It should be noted that each of the above modules may be implemented by software or hardware. For the latter, the foregoing may be implemented by, but not limited to, the foregoing modules are all located in the same processor; or, the modules are located in multiple In the processor.

The following is a detailed description in conjunction with the preferred embodiments of the invention.

The main technical feature of the preferred embodiment of the present invention is that when encoding or decoding a current block, constructing a representative pixel set of the current block, reconstructing pixel samples from the image region outside the current block and representative pixels of the current block The set of pixel values, optionally in combination with other codec parameters, obtains predicted values for some or all of the current pixel samples according to predetermined rules.

FIG. 5 is a schematic diagram of obtaining a current pixel prediction value according to a preferred embodiment of the present invention, constructing a representative pixel set of 8 representative pixels from a current block. For some or all of the pixels of the current block, the predicted values of some or all of the pixels of the current block are obtained from the reconstructed pixels of the image region outside the current block and the representative pixels of the current block.

The pixel shown in FIG. 5 may be in a stacked format or a flat format. Therefore, the method of the preferred embodiment of the present invention can be applied to encoding or decoding pixels of a coded block or a decoded block of a stacked packet format, and can also be applied to a pixel sample of a plane of a coded block or a decoded block of a planar format. Encoding or decoding.

In the encoding method of the preferred embodiment of the present invention, the most basic unique technical features are: counting and analyzing the characteristics of the current coding block, constructing a representative pixel set of the current coding block, also called a color palette; searching for the current coding block a predicted value of the pixel that best matches; the manner in which the predicted value is generated includes, but is not limited to, a reconstructed pixel sample from an image region other than the current encoded block and a pixel value of a representative pixel set of the current encoded block, optionally in combination with other The encoding parameters are obtained according to a predetermined rule; the information required to construct the representative pixel set is written into the video compressed code stream, and the information required to obtain the predicted value is written into the video compressed code stream.

In the decoding method of the preferred embodiment of the present invention, the most basic characteristic feature is that when the compressed code stream data of the current decoding block is decoded, the representative pixel set constructing the current decoding block is parsed from the code stream data, which is also called The information required by the palette is parsed to obtain the information required to obtain the predicted value of the pixel of the current decoded block; the calculation of the predicted value The manner includes, but is not limited to, reconstructed pixel samples from image regions outside the current decoded block and pixel values of representative pixel sets of the current decoded block, optionally in combination with other decoding parameters, calculated according to predetermined rules.

The technical features of the present invention have been described above by way of a number of specific specific examples. Other advantages and effects of the present invention will be readily apparent to those skilled in the art from this disclosure. The present invention may be embodied or applied in various other specific embodiments, and various modifications and changes may be made without departing from the spirit and scope of the invention.

FIG. 6 is a schematic flowchart of an encoding method according to a preferred embodiment of the present invention. As shown in FIG. 6, the encoding method of the present invention includes but is not limited to the following steps:

S601. Construct a representative pixel set of the coding block, at least generating information required to construct the representative pixel set;

S602. Perform prediction or copy coding on the coding block, and generate at least a prediction value of a pixel sample of the coding block, where the prediction value is generated by, but not limited to, an image region other than the coding block. Reconstructing pixel values and pixel values of the representative set of pixels, optionally in combination with other encoding parameters, calculated according to predetermined rules; the position of the reconstructed pixel samples in the image region is typically determined by the reconstructed pixels Specify the displacement vector (also called the motion vector or copy position, etc.) between the sample and the current encoded pixel sample;

S603, encoding at least information required to construct the representative pixel set and information required to obtain a predicted value, and writing the video compressed code stream.

FIG. 7 is a schematic flowchart of a decoding method according to a preferred embodiment of the present invention. As shown in FIG. 3, the decoding method of the present invention includes but is not limited to the following steps:

S701. Analyze a video code stream, and obtain at least information required to construct a representative pixel set of the decoded block and information required to obtain a predicted value of the pixel sample value of the decoded block;

S702. Construct the representative pixel set.

S703, generating at least the predicted value, where the predicted value is generated by, but not limited to, a reconstructed pixel sample from an image region other than the decoded block and a pixel value of the representative pixel set, optionally Combined with other decoding parameters, the calculation is obtained according to a predetermined rule. The position of the reconstructed pixel sample in the image region is typically specified by a displacement vector (also referred to as a motion vector or copy position, etc.) between the reconstructed pixel sample and the currently decoded pixel sample.

The illustrations provided above merely illustrate the basic idea of the present invention in a schematic manner, and only the components directly related to the present invention are shown in the drawings, rather than the number, shape and size of components in actual implementation, and the components in actual implementation. The type, quantity, and proportion can be a random change, and the component layout can be more complicated.

The following are more implementation details and variations of the invention.

A variant of the current coding block or current decoding block, a variant of the current coding block or the current decoding block is a pixel group or pixel string or pixel micro-block and pixel strip to be encoded or to be decoded. Correspondingly, the image area outside the coding block or the decoding block is an image area composed of pixels that have completed at least partial encoding or pixels that have completed at least partial decoding.

Embodiment 1 of the manner in which the predicted value is generated in the preferred embodiment of the present invention

The manner of generating the predicted value includes at least the following steps: selecting a reconstructed pixel sample or a variant thereof other than the codec block as a predicted value according to a predetermined rule, or selecting a pixel value of the representative pixel set or Its variant is used as a predictor. In a codec block, some or all of the current pixel samples adopt reconstructed pixel samples or variants thereof outside the codec block as prediction values, and some or all of the current pixel samples adopt the representative pixel set The pixel value or its variant is used as the predicted value. Such variants include, but are not limited to, filtering and transforming.

Embodiment 2 of the manner in which the predicted value is generated in the preferred embodiment of the present invention

The manner in which the predicted value is generated includes at least determining the predicted value based on at least part or all or a combination of the following parameters:

1) a position of the reconstructed pixel sample outside the codec block in the current image; the position is usually specified by a displacement vector (also called a motion vector or a copy position, etc.);

2) a value of the reconstructed pixel sample outside the codec block; the reconstructed pixel sample is usually specified by a displacement vector (also referred to as a motion vector or a copy position, etc.);

3) a value of a representative pixel sample value of the codec block;

4) a construction of a representative pixel set of the codec block;

5) the number of pixels of the representative pixel set of the codec block;

6) a location of a current codec pixel sample value in the codec block;

7) selecting according to the kind of the pixel component, one pixel component (such as Y component) or two pixel components (such as G component and R component) selecting a value representing the pixel sample as a predicted value, and other pixel components selecting the codec The value of the reconstructed pixel sample outside the block is used as a predicted value; the reconstructed pixel sample is usually specified by a displacement vector (also called a motion vector or a copy position, etc.);

8) A flag bit that is directly or implicitly derived in the code stream.

Embodiment 3 of the manner in which the predicted value is generated in the preferred embodiment of the present invention

For a current pixel sample of the codec block, the manner in which the predicted value is generated includes at least the following steps:

Determining a distance between the reconstructed pixel sample and a portion or all of the representative pixel samples of the representative pixel set for a reconstructed pixel sample other than the codec block The representative pixel sample is called the optimal representative pixel sample;

If the distance between the optimal representative pixel sample and the reconstructed pixel sample satisfies a predetermined condition, the value of the optimal representative pixel sample is selected as a predicted value, otherwise, the reconstructed pixel is selected The value of the sample is used as the predicted value.

Embodiment 4 of the manner in which the predicted value is generated in the preferred embodiment of the present invention

The distance in Embodiment 3 is an error between pixels, which is less than a predetermined threshold. That is, for a current pixel sample of the codec block, the manner in which the predicted value is generated includes at least the following steps:

1) calculating, for a reconstructed pixel sample other than the codec block, an error between the reconstructed pixel sample and a part or all of the representative pixel sample of the representative pixel set, determining one of the errors Small representative pixel samples, called optimal representative pixel samples;

2) if the error between the optimal representative pixel sample and the reconstructed pixel sample is less than a predetermined threshold, selecting a value of the optimal representative pixel sample as a predicted value; otherwise, selecting the weight Construct the value of the pixel sample as the predicted value.

Embodiment 5 of the manner in which the predicted value is generated in the preferred embodiment of the present invention

The position of the reconstructed pixel sample outside the codec block in Embodiment 2 in the current image is divided into a number of rows and/or columns directly adjacent to the codec block (typically 1-5 lines and / or 1-5 columns) and the rest of the location:

1) if the reconstructed pixel sample is located within a number of rows and/or columns directly adjacent to the codec block, selecting a value representative of the pixel sample as the predicted value;

2) Otherwise, that is, the reconstructed pixel samples are located outside of a number of rows and/or columns directly adjacent to the codec block, the value of the reconstructed pixel samples is selected as the predicted value.

Embodiment 6 of the manner in which the predicted value is generated in the preferred embodiment of the present invention

The flag bit described in Embodiment 2 appears directly or indirectly (implicitly derived form) in the following places in the code stream to determine that the current codec pixel value in the subsequent codec process is a value that selects a representative pixel value. As the predicted value, the value of the reconstructed pixel sample other than the codec block is selected as the predicted value:

1) a video parameter set; typically a grammatical element of a direct or implicit derivation of the video parameter set VPS;

2) a sequence parameter set; usually a grammatical element of a direct or implicit derivation of the sequence parameter set SPS;

3) an image parameter set; usually a grammatical element of the direct or implicit derivation of the image parameter set PPS;

4) a strip head; usually a grammatical element of a direct or implicit derivation of a stripe header;

5) CTU header; usually a grammatical element of a direct or implicit derivation of the CTU header;

6) CU header; usually a grammatic element of a direct or implicit derivation of the CU header;

7) a codec block header; usually a syntax element of a direct or implicit derivation of the codec block header;

8) before the codec block one or a group or a string of current codec pixel samples; usually one of the codec blocks or a set or a string of current codec pixel samples before the syntax element directly exists or hidden Contains derived syntax elements.

Embodiment 7 of the manner in which the predicted value is generated in the preferred embodiment of the present invention

The predicted value is determined according to the number of pixels of the representative pixel set of the codec block described in Embodiment 2:

1) if the number of pixels is less than a threshold, selecting a value representing a pixel sample as a predicted value;

2) Otherwise, the value of the reconstructed pixel sample is selected as the predicted value.

Embodiment 8 of the manner in which the predicted value is generated in the preferred embodiment of the present invention

For the method of embodiment 3 or embodiment 4, the encoder chooses to use one of the optimal representative pixel samples and the reconstructed pixel samples as the predicted value.

Optionally, the encoder sets a flag bit for identifying the selected prediction value, and writing the flag bit to the code stream using at least one of the following methods: (Method 1) is used to identify the selected sequence for the entire sequence. The flag of the predicted value is written into one or more parameter sets of the video parameter set VPS, the sequence parameter set SPS, and the image parameter set PPS; (method 2) the flag bits for identifying the predicted value used for the image are written. At least one of image parameter set PPS, slice (also called stripe) header information; (method 3) writing a flag bit for identifying a prediction value selected for the block layer to a maximum coding unit (or coding tree unit CTU) At least one of a layer, a coding unit CU layer. Correspondingly, the decoder obtains the value of the flag bit by parsing the code stream, and determines whether the optimal representative pixel sample value or the reconstructed pixel sample value is used as the predicted value in the decoding process according to the value of the flag bit.

Alternatively, the encoder does not write a flag bit for identifying the selected prediction value to the code stream, and the encoder defaults to using the prediction value candidate that satisfies the predetermined condition as the prediction value used in the encoding process. Correspondingly, the decoder selects the predicted value candidate satisfying the condition as the predicted value used in the decoding process using the same predetermined condition as the encoder.

Optionally, the encoder does not write the flag bit for identifying the selected prediction value into the code stream, and the encoder uses the prediction value candidate that satisfies the predetermined condition as the prediction value used in the encoding process, and at the same time, the encoder will The parameter of the predetermined condition is written into the code stream, and the parameter of the predetermined condition is written into the code stream using at least one of the following methods: (Method 1) writing the parameter for the predetermined condition of the entire sequence to the video parameter set One or more parameter sets in the VPS, the sequence parameter set SPS, and the image parameter set PPS; (method 2) writing parameters for identifying the predetermined condition of the image to at least one of the image parameter set PPS and the slice header information (Method 3) The parameter for identifying the predetermined condition of the block layer is written into at least one of a maximum coding unit (or coding tree unit CTU) layer and a coding unit CU layer. Correspondingly, the decoder obtains the parameters of the predetermined condition by parsing the code stream, and selects the predicted value candidate satisfying the predetermined condition as the predicted value used in the decoding process according to the parameter and the predetermined condition.

Through the description of the above embodiments, those skilled in the art can clearly understand that the method according to the above embodiment can be implemented by means of software plus a necessary general hardware platform, and of course, by hardware, but in many cases, the former is A better implementation. Based on such understanding, the technical solution of the present invention, which is essential or contributes to the prior art, may be embodied in the form of a software product stored in a storage medium (such as ROM/RAM, disk, The optical disc includes a number of instructions for causing a terminal device (which may be a cell phone, a computer, a server, or a network device, etc.) to perform the methods described in various embodiments of the present invention.

Embodiments of the present invention also provide a storage medium. Optionally, in the embodiment, the foregoing storage medium may be configured to store program code for performing the following steps:

S1, constructing a representative pixel set of the coded block, and acquiring information required to construct the representative pixel set;

S2, performing prediction coding or copy coding on the coding block, and acquiring a prediction value of a pixel sample of the coding block, where the prediction value is generated by: reconstructing a pixel according to an image region other than the coding block And a pixel value of the representative pixel set, and combined with a predefined encoding parameter, the predicted value is obtained according to a predetermined rule;

S3, encoding information required to construct the representative pixel set and information required to acquire the predicted value, and writing the video code stream.

Optionally, in this embodiment, the foregoing storage medium may include, but not limited to, a USB flash drive, a Read-Only Memory (ROM), a Random Access Memory (RAM), a mobile hard disk, and a magnetic memory. A variety of media that can store program code, such as a disc or a disc.

Optionally, in this embodiment, the processor performs the methods and steps of the foregoing embodiments according to the stored program code in the storage medium.

For example, the specific examples in this embodiment may refer to the examples described in the foregoing embodiments and the optional embodiments, and details are not described herein again.

It will be apparent to those skilled in the art that the various modules or steps of the present invention described above can be implemented by a general-purpose computing device that can be centralized on a single computing device or distributed across a network of multiple computing devices. Alternatively, they may be implemented by program code executable by the computing device such that they may be stored in the storage device by the computing device and, in some cases, may be different from the order herein. The steps shown or described are performed, or they are separately fabricated into individual integrated circuit modules, or a plurality of modules or steps thereof are fabricated as a single integrated circuit module. Thus, the invention is not limited to any specific combination of hardware and software.

The above description is only the preferred embodiment of the present invention, and is not intended to limit the present invention, and various modifications and changes can be made to the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and scope of the present invention are intended to be included within the scope of the present invention.

Industrial applicability

Based on the foregoing technical solution provided by the embodiment of the present invention, a representative pixel set of a coded block is constructed, and information required for constructing the representative pixel set is determined, and a predicted value of the pixel sample value in the coded block is constructed, where the predicted value is generated by: Constructing a predicted value of the pixel sample according to the reconstructed pixel sample of the image region outside the coded block and the pixel value of the representative pixel set, the information required to construct the representative pixel set and the need to construct the predicted value The information is encoded and written into the video code stream, which solves the problem that the position of the reconstructed pixels obtaining the predicted value is far from the current block, the correlation between the two is small, and the compression efficiency is low, and the problem is improved. The correlation between the predicted value of the image region from outside the current block and the pixel sample value effectively improves the compression efficiency.

Claims

An image encoding method comprising:

Constructing a representative set of pixels of the encoded block, determining information required to construct the representative set of pixels;

And constructing a predicted value of the pixel sample in the coding block, where the predicted value is generated by: reconstructing a pixel sample value of the image region other than the coded block and a pixel value of the representative pixel set, The predicted value of the pixel sample;

The information required to construct the representative set of pixels and the information required to construct the predicted values are encoded and written to the video stream.
The method of claim 1 wherein

The coding block is an coding region of an image, including at least one of: a maximum coding unit LCU, a coding tree unit CTU, a coding unit CU, a sub-region of a CU, a prediction unit PU, a transform unit TU, a pixel string, a pixel group, Pixel microblocks, pixel strips;

The image area other than the coded block includes at least one of: an image area other than the variant of the coded block; an image area formed by the partially coded pixels.
The method of claim 1, wherein the manner in which the predicted value is generated comprises one of the following:

Setting the predicted value to a reconstructed pixel sample or the reconstructed pixel sample variant outside the encoded block;

The predicted value is set to a pixel value of the representative pixel set or a pixel value variant of the representative pixel set.
The method of claim 1 wherein constructing a predicted value of a pixel sample in the encoded block using at least one of the following predefined encoding parameters comprises:

Reconstructing the position of the pixel sample in the image;

Constructing the information required to represent the set of pixels;

The number of pixels representing the set of pixels;

a location of a current encoded pixel sample in the encoded block;

a type of a pixel component of the coding block, wherein one pixel component or two of the pixel components of the pixel component select a pixel value of the representative pixel set as a predicted value, the pixel component except the one pixel component Or other pixel components other than the two pixel components, and selecting a pixel value of the reconstructed pixel sample as a predicted value;

The flag of the predicted value.
The method of claim 1, wherein for the pixel samples in the encoded block, the manner in which the predicted values are generated comprises:

Calculating a distance between the reconstructed pixel sample and a part or all of the representative pixel samples of the representative pixel set for the reconstructed pixel sample outside the coded block, and setting the optimal representative pixel sample value to The distance satisfies a representative pixel sample value of the first predefined condition;

And if the distance between the optimal representative pixel sample and the reconstructed pixel sample satisfies a second predefined condition, the predicted value is set to a value of the optimal representative pixel sample, if The second predefined condition is not met and the predicted value is set to the value of the reconstructed pixel sample.
The method of claim 5, wherein

The distance is an error between pixels, the first predefined condition is that the error is minimal, and the second predefined condition is that the error is less than a first predetermined threshold.
The method according to claim 5 or 6, wherein setting the predicted value to the optimal representative pixel sample or the reconstructed pixel sample further comprises:

Writing a flag bit identifying the predicted value in the video bitstream; and/or,

A condition parameter constructing the predicted value is written in the video code stream, wherein a pixel sample value satisfying the condition parameter is used as the predicted value.
The method of claim 7 wherein writing a flag identifying the predicted value in the video bitstream comprises at least one of:

Writing a flag bit for identifying a prediction value selected for the entire sequence into a parameter set of at least one of: a video parameter set VPS, a sequence parameter set SPS, and an image parameter set PPS;

Writing a flag bit for identifying a predicted value selected for the image to the image parameter set PPS and/or the slice header information;

A flag bit for identifying a prediction value selected for the block layer is written to the maximum coding unit LCU and/or the coding unit CU.
The method of claim 7, wherein the condition parameter constructing the predicted value is written in the video code stream, including at least one of the following:

Writing the predetermined condition parameter for the entire sequence to a parameter set of at least one of: a video parameter set VPS, a sequence parameter set SPS, and an image parameter set PPS;

Writing the predetermined condition parameters for the image to the image parameter set PPS and/or the slice header information;

The predetermined condition parameters for the block layer are written to the maximum coding unit LCU layer and/or the coding unit CU layer.
The method of claim 4, wherein

The position of the reconstructed pixel sample outside the encoded block in the image is divided into rows and/or columns adjacent to the encoded block;

If the reconstructed pixel sample is located within a row and/or column adjacent to the encoded block, setting the predicted value to a value representative of a pixel sample of the set of pixels;

The predicted value is set to a value of the reconstructed pixel sample if the reconstructed pixel sample is located outside of a row and/or column adjacent to the encoded block.
The method of claim 4, comprising:

The flag of the predicted value is directly obtainable from the video code stream or derived from existing parameters in the video code stream;

The flag of the predicted value is used to indicate that one of the values of the representative pixel samples of the representative pixel set and the reconstructed pixel samples of the coded block are selected as the current encoding in the encoding process. Pixel sample:

The flag bit includes one of the following locations at the location of the video stream:

Video parameter set, sequence parameter set, image parameter set, slice header, CTU header, CU header, coding block header, one, a group or a string of current coding pixel samples in the coding block.
The method of claim 4, wherein determining the predicted value based on the number of pixels of the representative set of pixels comprises:

And if the number of pixels is less than a second predetermined threshold, setting the predicted value to a value of a representative pixel sample of the representative pixel set;

If the number of pixels is not less than a second predetermined threshold, the predicted value is set as a value of the reconstructed pixel sample as a predicted value.
An image decoding method includes:

Parsing a code stream, obtaining a decoding parameter of the decoding block, where the decoding parameter includes at least one of: a parameter required to construct a representative pixel set of the decoding block; and constructing a pixel sample value in the decoding block The parameters required to predict the value;

The representative pixel set is constructed to determine a predicted value, wherein the predicted value is generated by constructing the predicted value according to the reconstructed pixel sample and the pixel value of the representative pixel set.
The method of claim 13 wherein

The decoding block is a decoding region of an image, including at least one of: a maximum coding unit LCU, a coding tree unit CTU, a coding unit CU, a sub-region of a CU, a prediction unit PU, a transform unit TU, a pixel string, a pixel group, Pixel microblocks, pixel strips;

The image area other than the decoded block includes at least one of: an image area other than the variant of the decoded block; an image area formed by the partially decoded pixel.
The method of claim 13, wherein the manner in which the predicted value is generated comprises one of the following:

Setting the predicted value to a reconstructed pixel sample or the reconstructed pixel sample variant outside the decoded block;

The predicted value is set to a pixel value of the representative pixel set or a pixel value variant of the representative pixel set.
The method of claim 13 wherein constructing a predicted value of a pixel sample in the decoded block using at least one of the predefined decoding parameters comprises:

Reconstructing the position of the pixel sample in the image;

Constructing the parameters required to represent the set of pixels;

The number of pixels representing the set of pixels;

a location of the currently decoded pixel sample in the decoded block;

a type of a pixel component of the decoding block, wherein one pixel component or two of the pixel components of the pixel component select a pixel value of the representative pixel set as a predicted value, the pixel component except the one pixel component Or other pixel components other than the two pixel components, and selecting a pixel value of the reconstructed pixel sample as a predicted value;

The flag of the predicted value.
The method of claim 13 wherein, for the pixel samples in the decoded block, the manner in which the predicted values are generated comprises:

Calculating a distance between the reconstructed pixel sample and a part or all of the representative pixel samples of the representative pixel set for the reconstructed pixel samples outside the decoded block, and setting the optimal representative pixel sample value to The distance satisfies a representative pixel sample value of the first predefined condition;

And if the distance between the optimal representative pixel sample and the reconstructed pixel sample satisfies a second predefined condition, the predicted value is set to a value of the optimal representative pixel sample, if The second predefined condition is not met and the predicted value is set to the value of the reconstructed pixel sample.
The method of claim 17 comprising:

The distance is an error between pixels, the first predefined condition is that the error is minimal, and the second predefined condition is that the error is less than a first predetermined threshold.
The method according to claim 17 or 18, wherein setting the predicted value to the optimal representative pixel sample or the reconstructed pixel sample comprises:

Parsing a flag bit in the code stream, setting the predicted value to a value indicated by the flag bit; and/or

A condition parameter in the code stream is parsed, and the predicted value is set to a pixel sample that satisfies the condition parameter.
The method of claim 19 wherein parsing the flag bits in the code stream comprises at least one of:

The parameter set for parsing the flag bit used to identify the prediction value selected for the sequence includes at least one of the following: a video parameter set VPS, a sequence parameter set SPS, and an image parameter set PPS;

Parsing an image parameter set PPS and/or strip header information of a flag bit for identifying a predicted value selected for the image;

A maximum coding unit LCU layer and/or a coding unit CU layer in which the flag bits for identifying the prediction values selected for the block layer are located are parsed.
The method of claim 19 wherein parsing the predetermined condition parameters in the code stream comprises at least one of:

Parsing a parameter set for the predetermined condition parameter of the sequence, the parameter set comprising at least one of the following: a video parameter set VPS, a sequence parameter set SPS, and an image parameter set PPS;

Parsing an image parameter set PPS and/or strip header information for the predetermined condition parameter of the image;

A maximum coding unit LCU layer and/or a coding unit CU layer in which the predetermined condition parameter for the block layer is located is parsed.
The method of claim 16 comprising:

The position of the reconstructed pixel samples outside the decoded block in the image is divided into rows and/or columns adjacent to the decoded block:

And if the reconstructed pixel sample is located in a row and/or column adjacent to the decoded block, setting the predicted value to a value of a representative pixel sample of the representative pixel set;

The predicted value is set to a value of the reconstructed pixel sample if the reconstructed pixel sample is located outside of a row and/or column adjacent to the decoded block.
The method of claim 16 comprising:

Parsing at least one of the data units in the code stream described below, obtaining a flag of the predicted value, the data unit comprising at least one of the following:

Video parameter set, sequence parameter set, image parameter set, slice header, CTU header, CU header, coding block header, one, a group or a string of current coding pixel samples before coding;

Wherein the flag of the predicted value is directly obtained from the code stream or obtained according to an existing parameter in the code stream; the flag bit of the predicted value indicates that the predicted value is set as the representative pixel The value of the set representative pixel sample is also the value of the reconstructed pixel sample outside the decoded block.
The method of claim 16 wherein determining the predicted value based on the number of pixels of the representative set of pixels comprises:

And if the number of pixels is less than a second predetermined threshold, setting the predicted value to a value of a representative pixel sample of the representative pixel set;

If the number of pixels is not less than a second predetermined threshold, the predicted value is set to a value of the reconstructed pixel sample.
An image encoding device comprising:

a first determining module, configured to construct a representative pixel set of the encoded block, and determine information required to construct the representative pixel set;

a second determining module, configured to construct a predicted value of the pixel sample of the encoded block, where the predicted value is generated by: reconstructing a pixel sample according to an image region other than the encoded block and the representative pixel set a pixel value that constructs a predicted value of the pixel sample;

An encoding module is arranged to encode information required to construct the representative set of pixels and information required to construct the predicted value, and write the code stream.
An image decoding device comprising:

a parsing module, configured to parse the code stream, to obtain a decoding parameter of the decoding block, where the decoding parameter includes at least one of the following parameters: constructing a parameter required for the representative pixel set of the decoding block, and constructing a pixel in the decoding block The parameters required for the predicted value of the sample;

a third determining module, configured to construct the representative pixel set, and determine a predicted value, where the predicted value is generated by: constructing the predicted value according to the reconstructed pixel sample and the pixel value of the representative pixel set .