WO2017137006A1

WO2017137006A1 - Encoding and decoding method and device for data compression

Info

Publication number: WO2017137006A1
Application number: PCT/CN2017/073247
Authority: WO
Inventors: 林涛; 赵利平; 周开伦; 王淑慧; 李明; 吴平; 吴钊
Original assignee: 同济大学; 中兴通讯股份有限公司
Priority date: 2016-02-10
Filing date: 2017-02-10
Publication date: 2017-08-17

Abstract

Provided are an encoding and decoding method and device for data compression. The encoding method comprises: performing an adaptive selection of a restricted string mode from multiple preset restricted string modes; and performing, according to the selected restricted string mode, string match encoding on an encoding block to obtain information of a restricted string encoded using the selected restricted string mode, and to obtain a compressed data bitstream of a syntax element of the restricted string encoded using the selected restricted string mode. The invention solves the problem of prior art string matching techniques having many matching parameters and consuming more bits to encode the same, thereby achieving higher string matching accuracy, reducing consumption of bits, and increasing encoding efficiency.

Description

Data compression coding and decoding method and device

Technical field

The present invention relates to the field of communications, and in particular to a method and apparatus for encoding and decoding data compression.

Background technique

As human society enters the era of big data, cloud computing, mobile computing, cloud-mobile computing, ultra-high definition (4K) and ultra-high definition (8K) video image resolution, 4G/5G communication, for various data, including large Data, image data, and video data are essential technologies for ultra-high compression ratio and extremely high-quality data compression.

A data set is a collection of samples of data (eg, bytes, bits, pixels, pixel components). When data encoding (and corresponding decoding) is performed on a data set (eg, a file, an image, a video sequence), the data set is usually divided into subsets of blocks called code blocks. The decoding angle is also the decoding block, collectively referred to as the codec block, and is coded or decoded in units of codec blocks. At any one time, the coded block being encoded is referred to as the current coded block. At any one time, the decoded block being decoded is referred to as the current decoded block. The current coded block or the current decoded block is collectively referred to as the current codec block or simply as the current block. The sample being encoded or decoded is called the current coded sample or the current decoded sample, which is simply referred to as the current sample.

A notable feature of many common data sets is that they have many matching (ie similar or even identical) styles. For example, there are often many matching pixel patterns in image and video sequences. Therefore, existing data compression techniques usually use matching (also called prediction or compensation), that is, using "predicted values" (also called "compensation values" or "reference samples", such as "reference pixels"). Matching (also known as prediction, representation, representation, compensation, approximation, approximation, etc.) current encoding or decoding of sample values (referred to as "current samples") to achieve lossless or lossy compression of the data. Simply put, the basic operation of the matching method is to copy the reference sample, that is, the position of the sample at the reference position to the current sample. Therefore, the matching mode or prediction mode is also called the copy mode. Horse In the allocation mode, the reconstructed (also called reconstructed or restored) samples that have undergone at least partial encoding operations and at least partial decoding operations constitute a primary reference set (also referred to as a primary reference space or a primary reference cache). The reconstructed samples and their positions in the primary reference set are in one-to-one correspondence with the original samples and their locations in the original data set. In the matching manner, in addition to the primary reference set, other reference sets may be constructed or generated, called a secondary reference set or a dependent reference set or a second reference set, a third reference set, and the like.

There are two commonly used matching methods: block matching mode and string matching mode. The block matching method is characterized in that the basic matching unit is a plurality of predetermined fixed-size blocks (sample blocks). The basic matching parameters of block matching (also known as matching or copying or copying) are displacement vectors (also known as motion vectors, positional offsets, offsets, relative positions, positions, relative addresses, addresses, relative coordinates, Coordinates, relative indexes, indexes, etc.). The displacement vector indicates the position (often referred to as the reference position) of the reference sample block (referred to as the reference block) of the current sample block (referred to as the current block). The string matching method is characterized in that the basic matching unit is a string (sample string) having a predetermined shape but a variable length. The basic matching parameters of the string match (also called the matching relationship or the copy parameter or the copy relationship) are displacement vectors (also called motion vectors, position offsets, offsets, relative positions, positions, relative addresses, addresses, relative coordinates, Coordinates, relative indexes, indexes, etc.) and string lengths and unmatched samples. The displacement vector indicates the reference position of the reference sample string (referred to as the reference string) of the current sample string (referred to as the current string), which is equivalent to the one-dimensional offset after the data samples are arranged into one-dimensional data. The string length indicates the length of the current string, that is, the number of samples. Unmatched samples are also referred to as no reference samples, indicating that there are no current samples of the reference samples.

If the codec block has a two-dimensional shape (not necessarily limited to a square or a rectangle, and may be any other reasonable two-dimensional shape), the sample values need to be coded in a certain order and then subjected to string matching. The arrangement is also called the scanning method. Scanning methods commonly used are horizontal scanning (which can be divided into gratings and bows) and vertical scanning (which can also be divided into gratings and bows).

String matching has a flexible matching shape and a variable matching length, which can achieve a much higher matching accuracy than block matching, but there are also matching parameters (also called matching relationships or copy parameters or copy relationships), which consume more The problem of encoding the number of bits affects the coding efficiency.

Summary of the invention

The embodiment of the invention provides a method and a device for encoding and decoding a data compression, so as to solve at least the problem that the string matching method in the related art has more matching parameters and consumes a larger number of bits to encode the same.

According to an aspect of an embodiment of the present invention, a data compression coding method is provided, including: adaptively selecting a restricted string mode from a preset plurality of restricted string modes; according to the selected restricted string mode Performing string matching encoding on the coded block to obtain information of the restricted string encoded using the selected restricted string mode, and compressed data bitstream of the syntax element of the restricted string encoded using the selected restricted string mode .

Optionally, the coding block is an coding region of an image, and the coding block includes at least one of the following: an image, a sub-image of an image, a macroblock, a maximum coding unit LCU, a coding tree unit CTU, a coding unit CU, a CU Sub-region, prediction unit PU, and transform unit TU.

Optionally, the restricted string mode includes at least one of the following conditions: the restricted string mode has a preset constraint; the restricted string mode has a plurality of preset constraints; the restricted string The mode does not have a preset constraint.

Optionally, the preset constraint condition of the restricted string mode is one or more combinations of the following basic constraints: a basic constraint condition 1: a value of a length of a reference sample from a preset range of reference positions There is an upper limit and/or a lower limit; basic constraint 2: the value of the reference sample from a preset range of the reference position is limited to a set of preset values; basic constraint 3: in a coding block, The reference sample has an upper limit on the number of strings from a preset reference set or a reference subset; basic constraint 4: in an encoding block, the reference sample has an upper limit from the number of strings of a preset range of the reference position; Basic constraint 5: the length of the string is equal to the number of samples of the coding block; the basic constraint 6: the length of the string is equal to one-half of the number of samples of the coding block; the basic constraint 7: the length of the string is equal to a preset value; basic constraint 8: the value of the length of the string is limited to a set of preset values; basic constraint 9: the coded block has a square shape and the length of the string is equal to a square Side length; basic constraint 10: The coding block has a rectangular shape and the length of the string is equal to the width or height of the rectangle; the basic constraint 11: the displacement vector of the string is equal to a preset value; the basic constraint 12: the displacement vector of the string of The value is limited to a set of preset values; basic constraint 13: the coded block has a square shape and the displacement vector of the string is equal to (0, 1) in horizontal scanning and equal to (1, 0) in vertical scanning, in conversion The equivalent one-dimensional offset is equal to the side length of the square; basic constraint 14: the coding block has a rectangular shape and the displacement vector of the string is equal to (0, 1) in horizontal scanning and equal to (1 in vertical scanning) , 0), equal to the width or height of the rectangle after conversion to the equivalent one-dimensional offset; basic constraint 15: the length of the string is limited to one or a set of preset values, and the displacement vector of the string The value is limited to one or a set of preset values; basic constraint 16: the length of the reference string is equal to 1, ie there is only one reference sample, and the length of the current string is greater than or equal to 1 and all current samples are equal to the reference Sample; basic constraint 17: reference sample is inside the current block; basic constraint 18: the coded block has a two-dimensional shape and the direction of all strings is vertical and the start and end points are on the block boundary; basic constraint 19: Code block has Shape and dimension in all directions are horizontal and string start and end points in the block boundary.

Optionally, the preset multiple restricted string mode includes three restricted string modes, where the preset constraint of the first restricted string mode includes the basic constraint 1 and the basic constraint The preset constraint condition of the second restricted string mode includes the basic constraint condition 5 and the basic constraint condition 6; the preset constraint condition of the third restricted string mode includes the basic constraint condition 13 The basic constraint 16 and the basic constraint 17 are described.

Optionally, the preset multiple restricted string modes include four restricted string modes, where a preset constraint condition of the first restricted string mode includes the basic constraint 1 and the basic constraint The preset constraint condition of the second restricted string mode includes the basic constraint condition 5 and the basic constraint condition 6; the preset constraint condition of the third restricted string mode includes the basic constraint condition 13 The basic constraint condition 16 and the basic constraint condition 17 are included; the preset constraint condition of the fourth restricted string mode includes the basic constraint condition 18 and the basic constraint condition 19.

Optionally, a preset range of the reference position in the basic constraint 1 is a range of a CTU and a neighboring K CTUs of the coding block, and an upper limit of the string length is 32 and/or a string length. The lower limit of the value is 1; the preset reference set or reference subset in the basic constraint 3 is a primary reference set, and the upper limit of the total number of strings is preset to be the total number of samples of the coded block multiplied by A score M/N.

Optionally, the enable flag of the multiple restricted string mode string matching mode exists in the compressed data bitstream, where the location of the enable flag bit includes at least the following in the compressed data bitstream. One: sequence parameter set, image parameter set, strip header, CTU header, CU header, coding block header.

Optionally, the preset multiple restricted string modes are respectively represented by a plurality of preset values, wherein one restricted string mode corresponds to a preset value k, and the coded block is compressed data. A coded stream has a restricted string mode identification code that is directly, or indirectly, or directly indirectly mixed; in the case where the restricted string mode identification code is equal to k, a restricted string mode pair corresponding to k is used. The coding block performs string matching coding.

Optionally, the direct restricted string mode identification code is composed of one or more bit strings in the compressed data code stream; the indirect restricted string mode identification code is from other coding parameters and/or compressed data. The restricted string mode identification code derived by other syntax elements of the code stream; the directly indirectly mixed restricted string mode identification code is a partially and partially indirectly mixed restricted string mode identification code.

Optionally, the restricted string mode identification code syntax element used to represent the restricted string mode of the coding block is present in the compressed data bitstream of the coding block in the following form: coding block header information, restricted string mode identifier a syntax element of a code, a sample string, or an unmatched sample; or, a coded block header information, a partially restricted string mode identification code, a partial syntax element of a first sample string, a remainder of a restricted string mode identification code, A value string or a syntax element that does not match the sample; wherein the coded block is subjected to string matching encoding using a restricted string mode corresponding to the value of the restricted string mode identification code.

According to another aspect of the embodiments of the present invention, there is provided an apparatus for encoding data compression, comprising: a selecting module configured to adaptively select a restricted string mode from a plurality of preset restricted string modes; encoding a module configured to perform string matching encoding on the coded block according to the selected restricted string mode to obtain information of a restricted string encoded using the selected restricted string mode, and encoding using the selected restricted string mode A compressed data stream of syntax elements of a restricted string.

According to still another aspect of the present invention, a decoding method for data compression is provided, comprising: parsing a compressed data code stream, acquiring information of a restricted string mode; and receiving information according to the restricted string mode from a preset plurality of Selecting a restricted string mode in the limited string mode to perform a string copy solution on the decoded block code.

Optionally, the decoding block is a decoding area of an image, and the decoding block includes at least one of the following: an image, a sub-image of an image, a macroblock, a maximum decoding unit LCU, a decoding tree unit CTU, a decoding unit CU, and a CU. Sub-region, prediction unit PU, and transform unit TU.

Optionally, the restricted string mode includes at least one of the following conditions: the restricted string mode optionally, the preset constraint condition of the one restricted string mode is one or more of the following basic constraints Combinations: Basic Constraint 1: Reference Samples There is an upper limit and/or a lower limit for the length of a string from a preset range of reference positions; Basic Constraint 2: Reference Samples are from a preset of the reference position The value of the length of the range string is limited to a set of preset values; basic constraint 3: in a decoding block, the number of reference samples from a preset reference set or a reference subset has an upper limit; basic constraints 4: In a decoding block, there is an upper limit on the number of strings whose reference samples are from a preset range of reference positions; basic constraint 5: the length of the string is equal to the number of samples of the decoded block; basic constraint 6: string The length is equal to one-half of the number of samples of the decoded block; the basic constraint 7: the length of the string is equal to a preset value; the basic constraint 8: the length of the string is limited to a set of presets Basic constraint 9: The decoding block has a square shape and the length of the string is equal to the side length of the square; basic constraint 10: the decoding block has a rectangular shape and the length of the string is equal to the width or height of the rectangle; basic constraint 11: string The displacement vector is equal to a preset value; basic constraint 12: the value of the displacement vector of the string is limited to a set of preset values; basic constraint 13: the decoded block has a square shape and the displacement vector of the string is horizontally scanned Equal to (0,1), equal to (1,0) in the vertical scan, equal to the side length of the square after conversion to the equivalent one-dimensional offset; basic constraint 14: the decoded block has a rectangular shape and the string The displacement vector is equal to (0,1) in horizontal scanning and equal to (1,0) in vertical scanning, equal to the width or height of the rectangle after conversion to an equivalent one-dimensional offset; basic constraint 15: string The value of the length is limited to one or a set of preset values, and the value of the displacement vector of the string is limited to one or a set of preset values; the basic constraint 16: the length of the reference string is equal to 1, that is, only one reference sample And the length of the current string is greater than or equal to 1 and all current samples are equal to the reference sample; basic constraint 17: the reference sample is inside the current block; basic constraint 18: the decoded block has a two-dimensional shape and all strings The direction is vertical and the starting point and The end points are all on the block boundary;

Basic Constraint 19: The decoded block has a two-dimensional shape and the direction of all strings is horizontal and both the start and end points are on the block boundary.

Optionally, the preset multiple restricted string modes include four restricted string modes, wherein a preset constraint condition of the first restricted string mode is the basic constraint 1 and the basic constraint The preset constraint condition of the second restricted string mode includes the basic constraint condition 5 and the basic constraint condition 6; the preset constraint condition of the third restricted string mode includes the basic constraint condition 13 The basic constraint condition 16 and the basic constraint condition 17 are included; the preset constraint condition of the fourth restricted string mode includes the basic constraint condition 18 and the basic constraint condition 19.

Optionally, a preset range of the reference position in the basic constraint 1 is an area range of the CTU and the adjacent K CTUs, and the upper limit of the string length is 32 and/or a string length. The lower limit of the value is 1; the preset reference set or reference subset in the basic constraint 3 is a primary reference set, and the upper limit of the total number of strings is preset to be the total number of samples included in the decoded block multiplied by A score M/N.

Optionally, the enable flag of the multiple restricted string mode string matching mode exists in the compressed data bitstream, where the location of the enable flag bit includes at least the following in the compressed data bitstream. One: sequence parameter set, image parameter set, strip header, CTU header, CU header, decoding block header.

Optionally, the preset multiple restricted string modes are respectively represented by a plurality of preset values, wherein one restricted string mode corresponds to a preset value k, and each of the decoded blocks is The compressed data stream has a restricted string mode identification code directly, or indirectly, or directly indirectly mixed; when the restricted string mode identification code is equal to k, a restricted string corresponding to k is used. Mode Performing string matching decoding on the decoded block.

Optionally, the direct restricted string mode identification code is composed of one or more bit strings in the compressed data code stream; the indirect restricted string mode identification code is from other decoding parameters and/or compressed data. The restricted string mode identification code derived by other syntax elements of the code stream; the directly indirectly mixed restricted string mode identification code is a partially and partially indirectly mixed restricted string mode identification code.

Optionally, the restricted string mode identification code syntax element used to represent the restricted string mode of the decoding block exists in the compressed data bitstream of the decoding block in the following form: decoding block header information, restricted string mode identifier a syntax element of a code, a sample string, or an unmatched sample; or, decoding block header information, a partially restricted string mode identification code, a partial syntax element of the first sample string, the remainder of the restricted string pattern identification code, A value string or a syntax element that does not match the sample; wherein the decoded block is subjected to string matching decoding using a restricted string mode corresponding to the value of the restricted string mode identification code.

According to still another aspect of the embodiments of the present invention, there is provided a data compression decoding apparatus, comprising: a parsing module configured to parse a compressed data code stream to obtain information of a restricted string mode; and a decoding module configured to be The information of the limited string mode selects one of the preset multiple string modes to perform a string copy decoding on the decoded block.

According to still another embodiment of the present invention, a storage medium is also provided. The storage medium is arranged to store program code for performing the following steps:

Adaptively selecting a restricted string mode from a plurality of preset restricted string modes; performing string matching encoding on the coded block according to the selected restricted string mode to obtain encoding by using the selected restricted string mode A limited string of information, and a compressed data stream of syntax elements of the restricted string encoded using the selected restricted string mode.

And parsing the compressed data code stream to obtain information of the restricted string mode; and selecting, according to the restricted string mode information, one of the preset multiple string modes to perform a string copy decoding on the decoded block.

Through an embodiment of the present invention, adaptively selecting one of a plurality of preset limited string modes a restricted string mode; further performing string matching encoding on the coded block in the compressed data according to the selected restricted string mode to obtain information of the restricted string encoded using the selected restricted string mode, and using the selected restricted string mode The manner of compressing the data stream of the encoded syntax element of the restricted string is performed by selecting a restricted string mode from a plurality of preset restricted string modes to encode the coded block in the data to be compressed, thereby reducing The matching parameters for encoding the coding block improve the matching precision of the string in the encoding process because only one type of the confined mode is matched, thereby solving the related art that the string matching method has more matching parameters and consumes more bits. The problem of coding.

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 flowchart 1 of an encoding method of data compression according to an embodiment of the present invention;

2 is a second flowchart of a decoding method of data compression according to an embodiment of the present invention;

3 is a structural block diagram 1 of an encoding apparatus for data compression according to an embodiment of the present invention;

4 is a block diagram showing the structure of a decoding apparatus for data compression according to an 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.

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

Step S102, adaptively selecting a restricted string mode from a preset plurality of restricted string modes;

Step S104, performing string matching encoding on the coding block according to the selected restricted string mode to obtain information of the restricted string encoded using the selected restricted string mode, and using the selected restricted string mode A compressed data stream of syntax elements of a restricted string that is encoded.

This embodiment provides a data compression method for performing string matching coding by using multiple restricted string modes. In the string matching mode, the restricted string refers to a string that is restricted by a preset constraint condition, and uses a restricted string mode pair. The coded block uses string constrained by the reservation constraint in the process of string matching encoding. With this embodiment, adaptively selecting a restricted string mode from a preset plurality of restricted string modes to indicate which restricted string mode is adopted by the coding block, and then treating according to the selected restricted string mode The coded block in the compressed data is subjected to string matching encoding to obtain information of the restricted string encoded using the selected restricted string mode, and the compressed data stream of the syntax element of the restricted string encoded using the selected restricted string mode In this manner, since a limited string mode is selected from a plurality of preset restricted string modes to encode a coded block in the compressed data, the matching parameter for encoding the coded block may be reduced, since only one type of string is encoded. The limit mode also improves the matching precision of the string in the encoding process, thereby solving the problem that the string matching method has more matching parameters and consumes more bits to encode the related art.

In an optional implementation manner of this embodiment, the data to be compressed involved in the embodiment includes at least one of the following: one-dimensional data, two-dimensional data, multi-dimensional data, images, sequences of images, video, audio, A collection of files, bytes, a collection of bits, a collection of pixels, and a collection of pixel components.

In addition, the coding block in this embodiment is an coding region of an image, and the coding block involved in this embodiment includes at least one of the following: an image, a sub-image of an image, a macroblock, a maximum coding unit LCU, and a coding tree unit CTU. a coding unit CU, a sub-area of the CU, a prediction unit PU, and a transform unit TU.

In addition, the restricted string mode involved in this embodiment includes at least one of the following conditions: the restricted string mode may have a preset constraint; the restricted string mode may have multiple preset constraints; The string limit mode may also have no preset constraints. When a plurality of restricted string modes are preset, wherein a plurality of preset constraints that exist in the plurality of preset constraints corresponding to the plurality of restricted string modes have overlapping portions, or multiple presets exist Multiple preset constraints among the constraints have no overlapping parts, for example, when the three restricted string modes are pre-set, the first restricted string The mode has a preset constraint, the second restricted string mode has two preset constraints, and the third restricted string mode does not have a preset constraint, so that it is possible that the first restricted string mode and the second The preset constraint conditions corresponding to the restricted string mode may overlap, or there may be no overlap between the preset constraints corresponding to the second restricted string mode and the third restricted string mode, but not Limited.

The preset constraint condition of the restricted string mode involved in this embodiment is composed of one or more of a plurality of basic constraints, wherein the factors related to the basic constraint include: reference samples and strings in the coding block The length and the displacement vector, the shape of the coding block.

In the following optional embodiments of the embodiment, the above factors related to the basic constraints are exemplified:

The basic constraints associated with the reference samples in the coded block may include:

Basic Constraint 1: The reference sample has an upper limit and/or a lower limit for the length of the string from a preset range of the reference position;

In a specific application scenario, the basic constraint 1 may be: for an original string (the string involved in this embodiment), the reference string (ie, the reference sample) is a string located within a preset range, and reference The string can be represented by a reference position, the length of the original string conforming to the above characteristics is L, and for L, there is an upper limit and/or a lower limit.

Basic constraint 2: The value of the length of the reference sample from a preset range of reference positions is limited to a set of preset values;

In a specific application scenario, the basic constraint 2 is substantially the same as the basic constraint 1 described above, except that the value of L is a value of a set of preset values.

Basic constraint 3: In a coding block, there is an upper limit on the number of reference samples from a preset reference set or a reference subset;

In a specific application scenario, the basic constraint 3 may be: for an original string, the reference string is a string located within a preset range, and the number of lengths of the original string having the above feature is N, N. There is an upper limit.

Basic Constraint 4: In a coded block, there is an upper limit on the number of strings in which the reference sample comes from a preset range of reference positions.

In a specific application scenario, the basic constraint 4 is similar to the basic constraint 3, except that the "number of strings" (with an upper limit) is defined here instead of "reference samples" from a "number".

Basic constraints related to the length of the string can include:

Basic constraint 5: the length of the string is equal to the number of samples of the coding block;

Basic constraint 6: the length of the string is equal to one-half of the number of samples of the coded block;

Basic constraint 7: The length of the string is equal to a preset value;

Basic constraint 8: The value of the length of the string is limited to a set of preset values;

It can be known from the above basic constraints 5 to 8 that the length of the string may be one or a set of preset values, or may be related to the samples of the coding block, for example, the length of the string is equal to the number of samples of the coding block, and the string. The length is equal to one-half of the number of samples of the encoded block.

The basic constraints associated with the shape of the coding block and the length of the string may include:

Basic constraint 9: the coding block has a square shape and the length of the string is equal to the side length of the square;

Basic Constraint 10: The coded block has a rectangular shape and the length of the string is equal to the width or height of the rectangle.

The basic constraints associated with the displacement vector of the string, the shape of the coding block, and the string length and reference samples may include:

Basic constraint 11: The displacement vector of the string is equal to a preset value;

Basic constraint 12: The value of the displacement vector of the string is limited to a set of preset values;

Basic Constraint 13: The coded block has a square shape and the displacement vector of the string is equal to (0, 1) in horizontal scanning and equal to (1, 0) in vertical scanning, after conversion to an equivalent one-dimensional offset Equal to the side length of the square;

Basic constraint 14: The coding block has a rectangular shape and the displacement vector of the string is equal to (0, 1) in horizontal scanning and equal to (1, 0) in vertical scanning, after conversion to an equivalent one-dimensional offset Equal to the width or height of the rectangle;

Basic constraint 15: the value of the length of the string is limited to one or a set of predetermined values, and the value of the displacement vector of the string is limited to one or a set of predetermined values;

Basic constraint 16: The length of the string is equal to 1, that is, there is only one reference sample, and the current string length is greater than or equal to 1, then all current samples are equal to the reference sample;

Basic constraint 17: The reference sample is inside the current block;

Basic constraint 18: The coding block has a two-dimensional shape and the directions of all the strings are vertical and the start and end points are on the block boundary;

Basic Constraint 19: The coded block has a two-dimensional shape and the direction of all strings is horizontal and both the start and end points are on the block boundary.

Based on the above basic constraints, the preset constraint condition of the restricted string mode involved in the embodiment may be combined by one or more of the above basic constraints 1 to 19.

It can be seen from the above basic constraints that the restricted string in this embodiment refers to a string that is restricted by a preset basic constraint. When encoding a coded block using a restricted string matching mode, a restricted string mode of the coded block means that all of the strings in the coded block are limited by one or a set of preset constraints. string. Different restricted string patterns have different one or a set of preset constraints. Under the limitation of one or a set of preset constraints, the type, type, and number of optional strings are greatly reduced, so that the number of matching parameters and/or the range of values are also greatly reduced, and the encoding is required to be consumed. The number of bits is also greatly reduced.

It should be noted that a preset range of the reference position in the basic constraint 1 is a range of the CTU and the adjacent K CTUs of the current block, and the upper limit of the length of the string is 32 and the preset lower limit is 1; the basic constraint The preset reference set or reference subset in Condition 3 is the primary reference set, and the preset upper limit of the total number of strings is the total number of samples of the current block multiplied by a fraction M/N, and both M and N are positive integers.

Based on the above basic constraints, in an optional implementation manner of this embodiment, the preset The plurality of restricted string modes include three restricted string modes: a preset constraint of the first restricted string mode includes a basic constraint 1 and a basic constraint 3; and a preset constraint of the second restricted string mode includes: The basic constraint condition 5 and the basic constraint condition 6; the preset constraint condition of the third restricted string mode includes the basic constraint condition 13, the basic constraint condition 16, and the basic constraint condition 17.

In another alternative embodiment of this embodiment, the plurality of restricted string modes preset include four restricted string modes: the preset constraint conditions of the first restricted string mode include basic constraint 1 and basic constraints 3; the preset constraint condition of the second restricted string mode includes the basic constraint condition 5 and the basic constraint condition 6; the preset constraint condition of the third restricted string mode includes the basic constraint condition 13, the basic constraint condition 16 and the basic constraint condition Condition 17; the preset constraint of the fourth restricted string mode includes a basic constraint 18 and a basic constraint 19.

In another optional implementation manner of this embodiment, there are multiple enabled string mode matching manner enable flag bits in the compressed data bitstream, where the location of the enable flag bit is included in the compressed data bitstream. At least one of the following: sequence parameter set, image parameter set, slice header, CTU header, CU header, coding block header.

For the enable flag bit, when encoding the coded block in the string matching mode by using multiple restricted string modes, the direct or indirect identification code is used in the header information of the coded block to indicate which one of the current block is used. In the limited string mode, an optimal constrained string mode can be adaptively selected according to the data characteristics of the codec block, which can achieve high string matching precision, reduce the number of consumed bits, and greatly improve coding efficiency.

In addition, the multiple restricted string modes related to the preset amount in the embodiment are respectively represented by a plurality of preset values, wherein one restricted string mode corresponds to a preset value k, and the coded block is The compressed data stream has a restricted string mode identification code directly or indirectly or directly indirectly mixed; in the case where the restricted string mode identification code is equal to k, a restricted string mode pair coding block corresponding to k is used. Perform string matching encoding.

Wherein the direct restricted string mode identification code is composed of one or more bit strings in the compressed data code stream; the indirect restricted string mode identification code is other syntax elements from other coding parameters and/or compressed data code streams. Derived restricted string mode identification code; direct indirect mixed restricted string mode The identification code is a restricted string mode identification code that is partially and partially indirectly mixed; the k is a positive integer.

It should be noted that the restricted string mode identification code syntax element used in the embodiment to represent the restricted string mode of the coding block exists in the compressed data code stream of the coding block in the following form:

a syntax element that encodes block header information, a restricted string mode identification code, a sample string, or an unmatched sample; or, a coded block header information, a partially restricted string mode identification code, a partial syntax element of the first sample string, or a restricted The syntax element of the remaining part of the string pattern identification code, the sample string or the unmatched sample; wherein the coded block is subjected to string matching encoding by using the restricted string mode corresponding to the value of the restricted string mode identification code.

Example 2

2 is a flowchart of a decoding method of data compression according to an embodiment of the present invention. As shown in FIG. 2, the steps of the method include:

Step S202: Parsing the compressed data code stream to obtain information of the restricted string mode;

Step S204: Perform string copy decoding on the decoded block by selecting a restricted string mode from a preset plurality of restricted string modes according to the information of the restricted string mode.

In an optional implementation manner of this embodiment, the data to be decompressed in this embodiment includes at least one of the following: one-dimensional data, two-dimensional data, multi-dimensional data, images, sequences of images, video, audio, A collection of files, bytes, a collection of bits, a collection of pixels, and a collection of pixel components.

In addition, the restricted string mode involved in this embodiment includes at least one of the following conditions: the restricted string mode may have a preset constraint; the restricted string mode may have multiple preset constraints; The string limit mode may also have no preset constraints. When a plurality of restricted string modes are preset, wherein a plurality of preset constraints that exist in the plurality of preset constraints corresponding to the plurality of restricted string modes have overlapping portions, or multiple presets exist Multiple pre-conditions Let the constraint have no overlapping parts. For example, when there are three restricted string modes, the first restricted string mode has one preset constraint, and the second restricted string mode has two preset constraints. The three restricted string modes do not have preset constraints, so that it is possible that the first restricted string mode and the second restricted string mode have overlapping portions, or may be the second limited. The preset constraint corresponding to the string mode and the third restricted string mode has no overlap, but is not limited thereto.

Basic constraints related to the length of the string can include:

Basic constraint 7: The length of the string is equal to a preset value;

Basic constraint 16: The length of the reference string is equal to 1, ie there is only one reference sample, and the length of the current string is greater than or equal to 1 and all current samples are equal to the reference sample;

Basic constraint 17: The reference sample is inside the current block;

In another optional implementation manner of this embodiment, there are multiple enabled string mode matching manner enable flag bits in the decompressed data bitstream, where the location of the enable flag bit is included in the decompressed data bitstream. At least one of the following: sequence parameter set, image parameter set, slice header, CTU header, CU header, coding block header.

In addition, the multiple restricted string modes related to the preset amount in the embodiment are respectively represented by a plurality of preset values, wherein one restricted string mode corresponds to a preset value k, and the coded block is The decompressed data stream has a restricted string mode identification code directly or indirectly or directly indirectly mixed; in the case where the restricted string mode identification code is equal to k, a restricted string mode pair coding block corresponding to k is used. Perform string matching encoding.

Wherein the direct restricted string mode identification code is composed of one or more bit strings in the decompressed data code stream; the indirect restricted string mode identification code is other syntax elements from other coding parameters and/or decompressed data stream. Derived restricted string mode identification code; direct indirect mixed restricted string mode The identification code is a restricted string mode identification code that is partially and partially indirectly mixed; the k is a positive integer.

It should be noted that the restricted string mode identification code syntax element used in the embodiment to represent the restricted string mode of the coding block exists in the decompressed data bitstream of the coding block in the following form:

It should be noted that the second embodiment is a decoding method corresponding to the encoding method of the first embodiment.

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.

Example 3

An encoding device for data compression is also provided in this embodiment, and the device is used to implement the foregoing embodiments and preferred embodiments, and details are not described herein. 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.

3 is a structural block diagram of an encoding apparatus for data compression according to an embodiment of the present invention. As shown in FIG. 3, the apparatus includes: a selecting module 32 configured to adaptively select one of a plurality of preset limited string modes. Limited string mode; encoding module 34, coupled with the selection module 32, set Performing string matching encoding on the coded block according to the selected restricted string mode results in information of the restricted string encoded using the selected restricted string mode, and syntax elements of the restricted string encoded using the selected restricted string mode Compress the data stream.

In addition, the restricted string mode involved in this embodiment includes at least one of the following conditions: the restricted string mode may have a preset constraint; the restricted string mode may have multiple preset constraints; The string limit mode may also have no preset constraints. When a plurality of restricted string modes are preset, wherein a plurality of preset constraints that exist in the plurality of preset constraints corresponding to the plurality of restricted string modes have overlapping portions, or multiple presets exist The plurality of preset constraints in the constraint have no overlapping portion. For example, when three restricted string modes are preset, the first restricted string mode has a preset constraint condition, and the second restricted string mode has Two preset constraints, the third restricted string mode does not have a preset constraint, so that it is possible that the first constraint type of the first restricted string mode and the second restricted string mode overlap. Or it is possible that the second restricted string mode and the third restricted string mode corresponding preset constraints have no overlapping parts, but are not limited thereto.

Basic constraints related to the length of the string can include:

Basic constraint 7: The length of the string is equal to a preset value;

Basic constraint 17: The reference sample is inside the current block;

Basic constraint 19: The coding block has a two-dimensional shape and the direction of all the strings is horizontal and Both the start and end points are on the block boundary.

Based on the foregoing basic constraint, in an optional implementation manner of this embodiment, the preset multiple restricted string modes include three restricted string modes: the preset constraint of the first restricted string mode includes a basic constraint. Condition 1 and basic constraint 3; the preset constraint condition of the second restricted string mode includes a basic constraint condition 5 and a basic constraint condition 6; the preset constraint condition of the third restricted string mode includes a basic constraint condition 13, and a basic constraint condition Constraint 16 and basic constraint 17.

In another optional embodiment of this embodiment, there are multiple types of compression in the compressed data stream. The enable flag of the string-string mode matching mode, wherein the position of the enable flag includes at least one of the following in the compressed data stream: a sequence parameter set, an image parameter set, a slice header, a CTU header, a CU header, and an encoding Block head.

Wherein the direct restricted string mode identification code is composed of one or more bit strings in the compressed data code stream; the indirect restricted string mode identification code is other syntax elements from other coding parameters and/or compressed data code streams. The derived restricted string mode identification code; the directly indirectly mixed restricted string mode identification code is a partially directly and partially indirectly mixed restricted string mode identification code; the k is a positive integer.

Example 4

4 is a structural block diagram of a decoding apparatus for data compression according to an embodiment of the present invention. As shown in FIG. 4, the apparatus includes: a parsing module 42 configured to parse a compressed data stream and obtain a restricted string. The information of the mode is coupled to the parsing module 42 and configured to perform a string copy decoding on the decoded block by selecting a restricted string mode from a preset plurality of restricted string modes according to the information of the restricted string mode.

Basic constraints related to the length of the string can include:

Basic constraint 7: The length of the string is equal to a preset value;

Basic constraint 16: The length of the reference string is equal to 1, that is, there is only one reference sample, and the current string length is greater than or equal to 1, then all current samples are equal to the reference sample;

Basic constraint 17: The reference sample is inside the current block;

In another optional implementation of this embodiment, there are multiple types of compression in the decompressed data stream. The enable flag of the string-limited mode string matching mode, wherein the position of the enable flag bit includes at least one of the following in the decompressed data bitstream: a sequence parameter set, an image parameter set, a slice header, a CTU header, a CU header, and an encoding Block head.

Wherein the direct restricted string mode identification code is composed of one or more bit strings in the decompressed data code stream; the indirect restricted string mode identification code is other syntax elements from other coding parameters and/or decompressed data stream. The derived restricted string mode identification code; the directly indirectly mixed restricted string mode identification code is a partially directly and partially indirectly mixed restricted string mode identification code; the k is a positive integer.

The present invention will be described in detail below with reference to specific embodiments of the embodiments of the present invention.

Example 5

In order to solve this problem in the string matching mode, the present embodiment provides a plurality of Data compression method for string matching codec in the limited string mode: In the string matching mode, the restricted string refers to a string that is limited by a preset constraint condition. When encoding and decoding a codec block using a string matching mode, a restricted string mode of the codec block means that all strings in the codec block are limited by one or a set of preset constraints. Restricted string. Different restricted string patterns have different one or a set of preset constraints. Under the limitation of one or a set of preset constraints, the type, type, and number of optional strings are greatly reduced, so that the number of matching parameters and/or the range of values are also greatly reduced, and the encoding is required to be consumed. The number of bits is also greatly reduced. The codec block is code-matched by using a plurality of (at least two) restricted string modes, and the direct or indirect identification code is used in the header information of the codec block to indicate which one of the codec blocks is used. In the limited string mode, an optimal constrained string mode can be adaptively selected according to the data characteristics of the codec block, which can achieve high string matching precision, reduce the number of consumed bits, and greatly improve coding efficiency.

In this embodiment, a plurality of (ie, two or more) codec block level restricted string modes are used for string matching codec.

Wherein, the restricted string mode may have a preset constraint condition, or a restricted string mode may have a set of (ie, two or more) preset constraint conditions; the one preset constraint condition is one Or a combination of multiple basic constraints.

In addition, the restricted string mode has a zero preset constraint condition, that is, there is no preset constraint condition; and two sets of preset constraint conditions corresponding to the plurality of restricted string modes have overlapping portions; Two sets of preset constraints among the multiple sets of preset constraints corresponding to the limited string mode have no overlapping parts.

In the encoding method of this embodiment, the current encoding block is subjected to string matching encoding by adaptively selecting a restricted string mode from a preset plurality of restricted string modes according to characteristics of a current encoding block, and A compressed data bitstream is generated that generates information of at least a plurality of restricted string patterns and a matching parameter of the corresponding restricted string (ie, a copy parameter required for decoding).

In the decoding method of the embodiment, the compressed data stream is parsed to obtain the information of the restricted string mode, and the information of the restricted string mode is used to adopt one of a plurality of preset limited string modes. The current decoded block is subjected to serial copy decoding.

It should be noted that the present embodiment is applicable to encoding and decoding of lossy data compression, and the present invention is equally applicable to encoding and decoding of lossless data compression. This embodiment is applicable to encoding and decoding of one-dimensional data such as character string data or byte string data, and the present invention is equally applicable to encoding and decoding of two-dimensional or above data such as image or video data.

Among them, the data involved in data compression includes one or a combination of the following types of data:

1) One-dimensional data;

2) two-dimensional data;

3) Multidimensional data;

4) image;

5) a sequence of images;

6) video;

7) audio;

8) documents;

9) a collection of bytes;

10) a collection of bits;

11) a collection of pixels;

12) A collection of pixel components.

In addition, in the embodiment, in the case where the data is an image, a sequence of images, a video, or the like, the coding block or the decoding block is one coding region or one decoding region of the image, including at least one of the following: a sub-image of the image, a macroblock 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 transform unit TU.

The restricted string mode involved in this embodiment has one of the following characteristics or a reasonable combination thereof: the one restricted string mode has a preset constraint; the one restricted string mode has a set (multiple, ie two or more) preset constraints; the one restricted string mode has At least one preset constraint, the one predetermined constraint is a logical combination of one or more basic constraints; the one restricted string mode has a zero preset constraint, that is, there is no preset constraint; Two sets of preset constraints among the plurality of sets of preset constraints corresponding to the plurality of restricted string modes have overlapping portions; two sets of pre-sets of the plurality of sets of preset constraints corresponding to the plurality of restricted string modes Let the constraint have no overlap.

Specific specific implementation manners in this embodiment are described in detail below;

Alternative embodiment 1

The preset constraint condition of the restricted string mode involved in this embodiment is a combination of one or several of the following basic constraints:

Basic Constraint 1 Reference Sample The value of the length of the string from a preset range of the reference position has a preset upper limit and/or a preset lower limit;

Basic Constraint 2 Reference Sample The value of the length of the string from a preset range of the reference position is limited to a set of preset values;

Basic Constraint 3 In a codec block, the number of reference samples from a preset reference set or a reference subset has a preset upper limit;

Basic constraint 4 In a codec block, the reference sample has a preset upper limit from the number of strings of a preset range of the reference position;

The length of the basic constraint 5 string is equal to the number of samples of the codec block;

The length of the basic constraint 6 string is equal to one-half of the number of samples of the codec block;

The length of the basic constraint 7 string is equal to a preset value;

The value of the length of the basic constraint 8 string is limited to a set of preset values;

The basic constraint 9 codec block has a square shape and the length of the string is equal to the side length of the square;

Basic Constraint 10 The codec block has a rectangular shape and the length of the string is equal to the width or height of the rectangle;

Basic constraint 11 The displacement vector of the string is equal to a preset value;

Basic constraint 12 The value of the displacement vector of the string is limited to a set of preset values;

Basic Constraint 13 The codec block has a square shape and the displacement vector (horizontal component, vertical component) of the string is equal to (0, 1) in horizontal scanning, equal to (1, 0) in vertical scanning, and converted to equivalent. The one-dimensional offset is equal to the side length of the square;

Basic Constraint 14 The codec block has a rectangular shape and the displacement vector (horizontal component, vertical component) of the string is equal to (0, 1) in horizontal scanning, equal to (1, 0) in vertical scanning, and converted to equivalent. The one-dimensional offset is equal to the width or height of the rectangle;

Basic constraint 15 The value of the length of the string is limited to one or a set of preset values, and the value of the displacement vector of the string is limited to one or a set of preset values;

Basic constraint 16 The length of the reference string is equal to 1, ie there is only one reference sample, and the length of the current string is greater than or equal to 1 and all current samples are equal to the reference sample;

The basic constraint 17 reference sample is inside the current block;

Basic Constraint 18 The codec block has a two-dimensional shape and the direction of all strings is vertical and the start and end points are on the block boundary;

Basic Constraints 19 The codec block has a two-dimensional shape and the direction of all strings is horizontal and the start and end points are on the block boundary.

Optional implementation method 2

The preset multiple restricted string modes are the following three restricted string modes:

The first constraint of the first restricted string mode is the basic constraint 1 and the basic constraint 3. That is to say, the codec block using the first restricted string mode is subject to the following restrictions: 1) If the reference sample of a string comes from a preset range of the reference position, the length of the string has a value The upper limit and/or a preset lower limit are set; 2) In the codec block, the total number of reference samples from a preset reference set or a reference subset has a preset upper limit.

The preset constraints of the second restricted string mode are the basic constraint 5 and the basic constraint 6. That is to say, the codec block using the second restricted string mode is subject to the following restrictions: A code block or a string having only one string length equal to the number of samples of the codec block, or only two strings having a string length equal to one-half of the number of samples of the codec block.

The preset constraints of the third restricted string mode are the basic constraint 13, the basic constraint 16, and the basic constraint 17. That is to say, the codec block adopting the third restricted string mode is subject to the following limitation: the codec block has a square shape in which any one of the strings or its displacement vector (horizontal component, vertical component) is equal to horizontal scanning. (0,1), equal to (1,0) in the vertical scan, equal to the side length of the square after conversion to the equivalent one-dimensional offset (ie the current string of this string is to move the reference string by one row or column) The position obtained or its current sample is equal to one reference sample, and all reference samples of the codec block are from the inside of the codec block.

Alternative embodiment 3

In the optional implementation manner 1, the preset multiple restricted string modes include four restricted string modes: the preset constraint condition of the first restricted string mode is equivalent to the first limited of the implementation or variant example 2. Preset constraints for string mode.

The preset constraint of the second restricted string mode is equivalent to the preset constraint of the second restricted string mode of the implementation or variant 2.

The preset constraint of the third restricted string mode is equivalent to the preset constraint of the third restricted string mode of the implementation or variant 2.

The preset constraints of the fourth restricted string mode are the basic constraint 18 and the basic constraint 19. That is to say, the codec block adopting the fourth restricted string mode is subject to the following restrictions: the codec block has a two-dimensional shape and the direction of all its strings is vertical or the direction of all its strings is horizontal and the start and end points are horizontal All on the block boundary.

Alternative embodiment 4

In the above optional embodiments 1-3, a preset range of the reference position in the basic constraint 1 is the CTU and the proximity of the current block (left or left and/or upper left and/or upper and/or upper right) Square) K (usually 1 ≤ K ≤ 4) area range composed of CTUs, the preset upper limit of the length of the string is 32 (inclusive) and the preset lower limit is 1 (inclusive), the preset in the basic constraint 3 The reference set or reference subset is the primary reference set, and the upper limit of the total number of strings is the total number of samples of the current block multiplied by a fraction M/N (usually 1 ≤ M < N ≤ 16).

Alternative embodiment 5

In the encoding method or the decoding method, there are multiple enabled string mode matching mode enable flag bits at one or several places in the compressed data stream:

1) a sequence parameter set; usually a grammatical element of a direct or implicit derivation of a sequence parameter set;

2) an image parameter set; usually a grammatical element of a direct or implicit derivation of an image parameter set;

3) Strip head; usually a grammatical element of the direct or implicit derivation of the strip head;

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

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

6) Codec block header; usually a directly existing or implicitly derived syntax element of the codec block header.

Alternative embodiment 6

In the encoding method or the decoding method, the preset multiple restricted string modes are respectively represented by a plurality of preset values, and one restricted string mode corresponds to a preset value k, and each codec block is compressed. The data stream has a restricted string mode identification code that is directly or indirectly or directly indirectly mixed.

If the restricted string mode identification code is equal to k, then

{

Performing string matching encoding and decoding on codec blocks using a restricted string mode corresponding to k

}

The direct restricted string mode identification code consists of one or more bit strings (bit strings) in the compressed data stream. The indirect restricted string mode identification code is a restricted string mode identification code derived from other codec parameters and/or other syntax elements of the compressed data stream. Restricted series mode of direct indirect mixing The type identification code is a partially constrained (ie, consisting of one or more bit strings in a compressed data stream) partially indirectly (ie, derived from other codec parameters and/or other syntax elements of the compressed data stream). String mode identification code.

Alternative embodiment 7

In the encoding side or the decoding method, the restricted string mode identification code syntax element used to represent the restricted string mode of the codec block exists in the compressed data bitstream of the codec block in the following form:

Codec block header information, restricted string mode identification code, more codec block header information, sample string or unmatched sample syntax elements (1 ≤ N ≤ the total number of samples of the codec block); or,

Codec block header information, partially restricted string mode identification code, more codec block header information, partial syntax elements of the first sample string, remainder of the restricted string pattern identification code, sample string or unmatched samples The remaining syntax elements (1 ≤ N ≤ the total number of samples of the codec block);

Wherein, when the restricted string mode identification code takes a value, the codec block is subjected to string matching encoding and decoding by using the restricted string mode corresponding to the value.

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 in the present invention. Within the scope of protection.

Industrial applicability

In the encoding and decoding process of data compression in the embodiment of the present invention, adaptively selecting a restricted string mode from a preset plurality of restricted string modes; and further compressing the data according to the selected restricted string mode. The coding block performs string matching coding to obtain information of a restricted string encoded using the selected restricted string mode, and a manner of compressing the data stream of the syntax element of the restricted string encoded using the selected restricted string mode, Selecting a restricted string mode from a plurality of preset restricted string modes to encode the coded block in the compressed data, thereby reducing matching parameters for encoding the coded block, since only one type of the limited block mode is also used. The matching precision of the string in the encoding process is improved, thereby solving the problem that the string matching method has more matching parameters and consumes more bits in the related art.

Claims

A method of encoding data compression, comprising:

Adaptively selecting a restricted string mode from a plurality of preset limited string modes;

Performing string matching encoding on the coded block according to the selected restricted string mode results in information of the restricted string encoded using the selected restricted string mode, and a restricted string encoded using the selected restricted string mode A compressed data stream of syntax elements.
The method of claim 1 wherein

The coding block is an coding region of an image, and the coding block includes at least one of: an image, a sub-image of an image, a macroblock, a maximum coding unit LCU, a coding tree unit CTU, a coding unit CU, a sub-region of a CU, and a prediction. Unit PU, transform unit TU.
The method of claim 1, wherein the restricted string mode comprises at least one of the following conditions:

The restricted string mode has a preset constraint condition;

The restricted string mode has a plurality of preset constraints;

The restricted string mode does not have a preset constraint.
The method of claim 1 wherein the predetermined constraint condition of the restricted string mode is one or more combinations of the following basic constraints:

Basic Constraint 1: The reference sample has an upper limit and/or a lower limit for the length of the string from a preset range of the reference position;

Basic constraint 2: The value of the length of the reference sample from a preset range of reference positions is limited to a set of preset values;

Basic constraint 3: In a coding block, there is an upper limit on the number of reference samples from a preset reference set or a reference subset;

Basic constraint 4: In a coding block, there is an upper limit on the number of strings whose reference samples are from a preset range of reference positions;

Basic constraint 5: the length of the string is equal to the number of samples of the coding block;

Basic constraint 6: the length of the string is equal to one-half of the number of samples of the coded block;

Basic constraint 7: The length of the string is equal to a preset value;

Basic constraint 8: The value of the length of the string is limited to a set of preset values;

Basic constraint 9: the coding block has a square shape and the length of the string is equal to the side length of the square;

Basic constraint 10: The coding block has a rectangular shape and the length of the string is equal to the width or height of the rectangle;

Basic constraint 11: The displacement vector of the string is equal to a preset value;

Basic constraint 12: The value of the displacement vector of the string is limited to a set of preset values;

Basic Constraint 13: The coded block has a square shape and the displacement vector of the string is equal to (0, 1) in horizontal scanning and equal to (1, 0) in vertical scanning, after conversion to an equivalent one-dimensional offset Equal to the side length of the square;

Basic constraint 14: The coding block has a rectangular shape and the displacement vector of the string is equal to (0, 1) in horizontal scanning and equal to (1, 0) in vertical scanning, after conversion to an equivalent one-dimensional offset Equal to the width or height of the rectangle;

Basic constraint 15: the value of the length of the string is limited to one or a set of preset values, and the value of the displacement vector of the string is limited to one or a set of preset values;

Basic constraint 16: The length of the reference string is equal to 1, ie there is only one reference sample, and the length of the current string is greater than or equal to 1 and all current samples are equal to the reference sample value;

Basic constraint 17: The reference sample is inside the current block;

Basic constraint 18: The coding block has a two-dimensional shape and the directions of all the strings are vertical and the start and end points are on the block boundary;

Basic Constraint 19: The coded block has a two-dimensional shape and the direction of all strings is horizontal and both the start and end points are on the block boundary.
The method of claim 4, wherein

The preset plurality of restricted string modes includes three restricted string modes, wherein a preset constraint condition of the first restricted string mode includes the basic constraint condition 1 and the basic constraint condition 3; The preset constraint condition of the restricted string mode includes the basic constraint condition 5 and the basic constraint condition 6; the preset constraint condition of the third restricted string mode includes the basic constraint condition 13 and the basic constraint condition 16 and the basic constraint 17.
The method of claim 4, wherein

The preset multiple restricted string modes include four restricted string modes, wherein the preset constraint conditions of the first restricted string mode include the basic constraint 1 and the basic constraint 3; The preset constraint condition of the restricted string mode includes the basic constraint condition 5 and the basic constraint condition 6; the preset constraint condition of the third restricted string mode includes the basic constraint condition 13 and the basic constraint condition 16 and the basic constraint 17; the preset constraint of the fourth restricted string mode includes the basic constraint 18 and the basic constraint 19.
The method of claim 4, wherein

A preset range of the reference position in the basic constraint 1 is a range of regions in which the CTU of the coding block and the adjacent K CTUs are formed, and the upper limit of the string length is The lower limit of 32 and / or string length is 1;

The preset reference set or reference subset in the basic constraint 3 is a primary reference set, and the upper limit of the total number of strings is preset to be the total number of samples of the coding block multiplied by a fraction M/N.
The method of claim 1, wherein the plurality of restricted string mode string matching mode enable flag bits are present in the compressed data bitstream, wherein the location of the enable flag bit is compressed data The code stream includes at least one of the following:

Sequence parameter set, image parameter set, strip header, CTU header, CU header, encoding block header.
The method of claim 1 wherein

The preset multiple restricted string modes are respectively represented by a plurality of preset values, wherein a restricted string mode corresponds to a preset value k, and the coded block is in a compressed data stream. There is a restricted string mode identification code that is directly, or indirectly, or directly indirectly mixed;

In the case that the restricted string mode identification code is equal to k, the coded block is subjected to string matching encoding using a restricted string mode corresponding to k.
The method of claim 9 wherein

The direct restricted string mode identification code is composed of one or more bit strings in a compressed data code stream; the indirect restricted string mode identification code is from other encoding parameters and/or compressed data stream other The restricted string mode identification code derived by the syntax element; the directly indirectly mixed restricted string mode identification code is a partially directly and partially indirectly mixed restricted string mode identification code.
The method of claim 9 wherein

A restricted string mode identification code syntax element used to represent a restricted string mode of the coded block is present in the compressed data bitstream of the coded block in the following form:

a syntax element that encodes block header information, a restricted string mode identification code, a sample string, or an unmatched sample; or,

Encoding block header information, a partially restricted string mode identification code, a partial syntax element of the first sample string, a remainder of the restricted string mode identification code, a sample string, or a syntax element of an unmatched sample; The restricted string mode corresponding to the value of the limited string mode identification code performs string matching encoding on the coded block.
An encoding device for data compression, comprising:

Selecting a module, configured to adaptively select a restricted string mode from a plurality of preset restricted string modes;

An encoding module configured to perform string matching encoding on the encoded block according to the selected restricted string mode to obtain information of the restricted string encoded using the selected restricted string mode, and encoding using the selected restricted string mode A compressed data stream of syntax elements of a restricted string.
A decoding method for data compression, comprising:

Parsing the compressed data stream to obtain information of the restricted string mode;

And performing a string copy decoding on the decoded block by selecting one of the preset multiple string modes according to the restricted string mode information.
The method of claim 13 wherein

The decoding block is a decoding region of an image, and the decoding block includes at least one of: an image, a sub-image of an image, a macroblock, a maximum decoding unit LCU, a decoding tree unit CTU, a decoding unit CU, a sub-region of a CU, and a prediction. Unit PU, transform unit TU.
The method of claim 13, wherein the restricted string mode includes at least one of the following conditions:

The restricted string mode has a preset constraint condition;

The restricted string mode has a plurality of preset constraints;

The restricted string mode does not have a preset constraint.
The method of claim 13 wherein the predetermined constraint condition of the restricted string mode is one or more combinations of the following basic constraints:

Basic Constraint 1: The reference sample has an upper limit and/or a lower limit for the length of the string from a preset range of the reference position;

Basic constraint 2: The value of the length of the reference sample from a preset range of reference positions is limited to a set of preset values;

Basic constraint 3: In a decoding block, there is an upper limit on the number of reference samples from a preset reference set or a reference subset;

Basic constraint 4: In a decoding block, there is an upper limit on the number of strings in which the reference sample is from a preset range of reference positions;

Basic constraint 5: the length of the string is equal to the number of samples of the decoded block;

Basic constraint 6: the length of the string is equal to one-half of the number of samples of the decoded block;

Basic constraint 7: The length of the string is equal to a preset value;

Basic constraint 8: The value of the length of the string is limited to a set of preset values;

Basic constraint 9: The decoding block has a square shape and the length of the string is equal to the side length of the square;

Basic constraint 10: The decoding block has a rectangular shape and the length of the string is equal to the width or height of the rectangle;

Basic constraint 11: The displacement vector of the string is equal to a preset value;

Basic constraint 12: The value of the displacement vector of the string is limited to a set of preset values;

Basic Constraint 13: The decoded block has a square shape and the displacement vector of the string is equal to (0, 1) in horizontal scanning and equal to (1, 0) in vertical scanning, after conversion to an equivalent one-dimensional offset Equal to the side length of the square;

Basic Constraint 14: The decoded block has a rectangular shape and the displacement vector of the string is equal to (0, 1) in horizontal scanning and equal to (1, 0) in vertical scanning, after conversion to an equivalent one-dimensional offset Equal to the width or height of the rectangle;

Basic constraint 15: the value of the length of the string is limited to one or a set of preset values, and the value of the displacement vector of the string is limited to one or a set of preset values;

Basic constraint 16: the length of the reference string is equal to 1, ie there is only one reference sample, and the length of the current string is greater than or equal to 1 and all current samples are equal to the reference sample;

Basic constraint 17: The reference sample is inside the current block;

Basic constraint 18: The decoded block has a two-dimensional shape and the directions of all the strings are vertical and the start and end points are on the block boundary;

Basic Constraint 19: The decoded block has a two-dimensional shape and the direction of all strings is horizontal and both the start and end points are on the block boundary.
The method of claim 16 wherein

The preset plurality of restricted string modes includes three restricted string modes, wherein a preset constraint condition of the first restricted string mode includes the basic constraint condition 1 and the basic constraint condition 3; The preset constraint condition of the restricted string mode includes the basic constraint condition 5 and the basic constraint condition 6; the preset constraint condition of the third restricted string mode includes the basic constraint condition 13 and the basic constraint condition 16 and the basic constraint 17.
The method of claim 16 wherein

The preset multiple restricted string modes include four restricted string modes, wherein a preset constraint condition of the first restricted string mode is the basic constraint condition 1 and the basic constraint condition 3; The preset constraint condition of the restricted string mode includes the basic constraint condition 5 and the basic constraint condition 6; the preset constraint condition of the third restricted string mode includes the basic constraint condition 13 and the basic constraint condition 16 and the basic constraint 17; the preset constraint of the fourth restricted string mode includes the basic constraint 18 and the basic constraint 19.
The method of claim 16 wherein

A preset range of the reference position in the basic constraint 1 is an area range of the CTU and the adjacent K CTUs, and the upper limit of the string length is 32 and/or the lower limit of the string length is 1;

The preset reference set or reference subset in the basic constraint 3 is a primary reference set, and the upper limit of the total number of strings is preset to be the total number of samples included in the decoding block multiplied by a fraction M/N.
The method of claim 13, wherein the plurality of restricted string mode string matching mode enable flag bits are present in the compressed data bitstream, wherein the location of the enable flag bit is compressed data The code stream includes at least one of the following:

Sequence parameter set, image parameter set, strip header, CTU header, CU header, decoding block header.
The method of claim 13 wherein

The preset multiple restricted string modes are respectively represented by a plurality of preset values, wherein one restricted string mode corresponds to a preset value k, and each of the decoded blocks is in a compressed data stream. There is a restricted string mode identification code that is directly, or indirectly, or directly indirectly mixed;

In the case that the restricted string mode identification code is equal to k, the decoded block is subjected to string matching decoding using a restricted string mode corresponding to k.
The method of claim 21, wherein

The direct restricted string mode identification code is composed of one or more bit strings in a compressed data code stream; the indirect restricted string mode identification code is from other decoding parameters and/or compressed data stream other The restricted string mode identification code derived by the syntax element; the directly indirectly mixed restricted string mode identification code is a partially directly and partially indirectly mixed restricted string mode identification code.
The method of claim 21, wherein

A restricted string mode identification code syntax element used to represent a restricted string mode of the decoded block is present in the compressed data bitstream of the decoded block in the following form:

Decoding block header information, restricted string mode identification code, sample string, or syntax elements that do not match samples; or,

Decoding block header information, a partially restricted string mode identification code, a partial syntax element of the first sample string, a remainder of the restricted string pattern identification code, a sample string, or a syntax element of an unmatched sample; The restricted string mode corresponding to the value of the limited string mode identification code performs string matching decoding on the decoded block.
A decoding device for data compression, comprising:

a parsing module configured to parse the compressed data stream to obtain information of the restricted string mode;

The decoding module is configured to perform string copy decoding on the decoded block by selecting one of the preset multiple string modes according to the restricted string mode information.