CN102984523A - Multi-directional intra-frame forecast encoding and decoding method and device - Google Patents

Abstract

The present invention discloses an intra-frame prediction encoding and decoding method and device. The method includes the following steps: the encoding end, for an input intra-frame prediction unit, selects an intra-frame prediction unit for executing the direction according to a set intra-frame prediction direction. The reference pixels required for prediction; use the reference pixels to predict the prediction unit according to the set prediction direction to obtain the pixel prediction value of the prediction unit, and the pixel prediction value is filtered by the selected reference pixels Obtained; traverse all prediction directions, and perform entropy coding on the optimal prediction direction. The decoding end analyzes the intra-frame prediction mode, and uses the same intra-frame prediction method as the encoding end to obtain an intra-frame prediction value.

Description

A multi-directional intra-frame prediction encoding and decoding method and device

technical field

The present invention relates to the technical field of multimedia video encoding and decoding, in particular to a multi-directional intra-frame prediction encoding and decoding method and device.

Background technique

There are four types of redundancy in video sequences: temporal redundancy, spatial redundancy, visual redundancy, and coding redundancy. For the first two types of redundancy, we generally use predictive techniques to reduce this redundancy. According to different prediction modes, the prediction mode of the prediction unit can be divided into intra prediction and inter prediction. Among them, the intra-frame prediction refers to predictive coding by using only the spatial domain information of the current frame; and the inter-frame prediction refers to the predictive coding by using the time-domain information of adjacent frames. Generally speaking, the accuracy of inter-frame prediction is much higher than that of intra-frame prediction, but intra-frame prediction is especially important for coding blocks that have no temporal information or cannot find a matching block in the temporal domain. For example, for the first frame of a sequence, or random access points in the encoding process, they cannot refer to information in the temporal domain, but can only use the information of the current frame for intra-frame prediction. Moreover, the coding performance of the first frame of the sequence or the frame of the random access point is particularly important to the coding performance of the whole sequence. Because they serve as reference objects for subsequent inter-frame prediction, they can affect the encoding of subsequent frame pairs. Therefore, accurate intra-frame prediction technology plays a very important role in video coding.

In the existing published video coding standards, such as H.264 and AVS 1.0, there are only 9 intra-frame modes at most (8 directional prediction plus 1 DC mode, as shown in Figure 2), and the intra-frame prediction block The size is up to 16x16. However, in the high-efficiency video coding standard and the next-generation AVS standard AVS2.0, the coding unit (Coding Unit, CU) is the basic unit of video coding. The coding unit adopts a four-fork recursive division mode, and the coding unit can reach a maximum of 64x64 (as shown in Figure 1(a)), instead of 16x16. In each coding unit, do prediction, transform quantization, entropy coding, post-processing to encode. When the coding unit is making predictions, the coding unit can be divided into prediction units (Prediction Unit, PU) of different sizes, and the prediction unit is the basic unit of prediction. The division of intra prediction units in coding units is shown in Fig. 1(b). The maximum size of the intra prediction block can be 64x64, and the minimum is 8x8, which is no longer 16x16 in previous standards. If the 9 prediction modes are still used in the 64x64 intra prediction block, the accuracy of the prediction cannot be guaranteed.

Contents of the invention

In order to overcome the shortcomings of the prior art structure, the present invention provides a multi-directional intra-frame prediction encoding and decoding method and device.

The embodiment of the present invention discloses an intra-frame prediction encoding and decoding method, which includes the following steps: at the encoding end:

For an input intra-frame prediction unit, according to the set intra-frame prediction direction, select reference pixels required for performing intra-frame prediction in this direction;

Using the reference pixels to predict the prediction unit according to a set prediction direction to obtain a pixel prediction value of the prediction unit, and the pixel prediction value is obtained by filtering the selected reference pixels;

Traversing all prediction directions, entropy coding the optimal prediction direction;

Decoder:

Analyzing the intra prediction mode by using the inverse process of entropy coding at the encoding end;

For an input intra-frame prediction unit, according to the set intra-frame prediction direction, select reference pixels required for performing intra-frame prediction in this direction;

Using the reference pixels to predict the prediction unit according to the set prediction direction to obtain a pixel prediction value of the prediction unit, and the pixel prediction value is obtained by filtering the selected reference pixels.

Further, preferably, the set intra-frame prediction direction is extended by each pixel of the prediction unit to intersect with the coded pixel, and the relevant pixels around the extension line are selected as reference pixels.

Further, preferably, 33 direction predictions and one DC prediction are used for one prediction unit.

Further, as a preference, the 33 direction predictions specifically divide the angles deviating from the horizontal or vertical direction into 8 parts, and the angles deviating from the horizontal or vertical direction alpha=[3,7,12,18,24,31,38 ,45]/180*pi.

Further, preferably, a direction accuracy of 1/32 is adopted, and the angle deviates from the pixel distance l=[2, 4, 7, 10, 14, 19, 25, 32] in the horizontal or vertical direction.

Further, preferably, the direction is obtained by filtering 3 to 4 pixels around the intersection of the line where the pixel to be predicted and the line where the reference pixel intersects.

Further, preferably, the filtering is specifically: 4tap interpolation filtering, the 4tap interpolation filter coefficient values are respectively [32-k, 64-k, 32+k, k]/128, where k is the pixel position to be predicted The distance between the reference pixel point on the left or above of the intersection point of the straight line and the reference pixel and the intersection point of the straight line where the pixel position is to be predicted and the straight line where the reference pixel is located. The value range of k is [0,32].

Further, as a preference, when the intersection point of the straight line where the pixel position to be predicted and the straight line where the reference pixel is located is an integer pixel point, that is, k is 0 or 32, the 4tap filter degenerates into a 3tap filter, and the filter coefficient is [1,2,1].

Further, preferably, the entropy encoding specifically includes: performing binarization on the intra-frame prediction directions, and then entropy encoding, sorting the intra-frame prediction directions in order of occurrence probability from high to low, and sorting the directions with high probability Shorter codewords are assigned, and relatively longer codewords are assigned to directions with low occurrence probability.

On the other hand, an embodiment of the present invention also provides a multi-directional intra prediction coding and decoding device, which includes:

The reference pixel selection unit at the encoding end selects the reference pixels required for performing the prediction process according to the prediction mode;

The prediction value acquisition unit of the prediction unit at the encoding end selects the reference pixel required to predict the current pixel value according to the prediction direction and the position of the current prediction pixel, and performs an interpolation filtering process to obtain the prediction value;

The cost function calculation unit at the encoding end calculates the encoding cost of each prediction mode, and selects the prediction mode with the smallest encoding cost as the final encoding mode;

The intra prediction mode entropy encoding unit at the encoding end performs entropy encoding on the optimal encoding mode obtained at the encoding end, and outputs a code stream;

The intra-frame prediction mode entropy decoding unit at the decoding end uses the inverse process of entropy encoding at the encoding end to analyze the intra-frame prediction mode and obtain the intra-frame prediction mode from the code stream;

The cost function calculation unit at the decoding end calculates the decoding cost of each prediction mode, and selects the prediction mode with the smallest decoding cost as the final decoding mode;

The reference pixel selection unit at the decoding end selects the reference pixels required for performing the prediction process according to the prediction mode;

The prediction value acquisition unit of the prediction unit at the decoding end selects the reference pixel required to predict the current pixel value according to the prediction direction and the position of the current prediction pixel, and performs an interpolation filtering process to obtain a prediction value.

Preferably, the reference pixel selection unit selects according to the needs of the current prediction mode. The current prediction direction is extended by each pixel of the prediction unit to intersect with the encoded pixel, and the pixels involved around the extension line are selected as reference pixels.

Preferably, the predicted value acquisition unit of the prediction unit is obtained by filtering 3 to 4 pixels around the intersection point A of the straight line where the pixel position to be predicted and the straight line where the reference pixel is located by using this direction. The filter is a 4tap interpolation filter, and the coefficient of the filter is related to the distance between the reference pixel point and point A. The 4tap filter coefficient values are respectively [32-k, 64-k, 32+k, k]/128, where k is the distance from the reference pixel point on the left/upper side of point A to point A, and the value range of k is [0,32]. When point A is an integer pixel point, that is, k is 0 or 32, the 4tap filter degenerates into a 3tap filter, and the filter coefficient is [1,2,1].

Preferably, the prediction mode entropy coding unit sorts the intra-frame prediction directions in order of occurrence probability from high to low, assigns shorter codewords to directions with high probability, and assigns relatively longer codewords to directions with low occurrence probability. Codeword.

Preferably, in an embodiment of the present invention, the prediction mode analysis unit at the decoding end analyzes bits in the code stream to obtain a binary code of an intra prediction mode, and obtains a corresponding intra prediction mode according to the binary code.

In yet another aspect, an embodiment of the present invention also provides a system for implementing multi-directional intra-frame predictive coding, the system including:

The encoder is used to obtain the prediction values of a prediction unit in all prediction modes during the encoding process, calculate the encoding cost of each prediction mode, select the optimal encoding mode for entropy encoding, and output the code stream;

The decoder is configured to perform entropy decoding first in the decoding process to obtain its intra-frame prediction mode, and use the intra-frame prediction mode to predict the current prediction unit to obtain a prediction value.

The present invention solves the large-scale prediction prediction accuracy by increasing the prediction direction to 34 (33 direction prediction and 1 DC mode), and designing the method of reference pixel selection, interpolation filter and direction coding in multi-direction prediction Issues that do not meet requirements. The present invention can obtain more accurate prediction value, thereby reducing the residual error of prediction, and can improve the coding efficiency by 5.1%.

Description of drawings

A more complete and better understanding of the invention, and many of its attendant advantages, will readily be learned by reference to the following detailed description when considered in conjunction with the accompanying drawings, but the accompanying drawings illustrated herein are intended to provide a further understanding of the invention and constitute A part of the present invention, the exemplary embodiment of the present invention and its description are used to explain the present invention, and do not constitute an improper limitation of the present invention, wherein:

FIG. 1( a ) is a schematic diagram of coding unit division in the prior art of AVS2.

Fig. 1(b) is a schematic diagram of prediction unit division in another prior art of AVS2.

Fig. 2 is a schematic diagram of intra-frame directional prediction in the prior art.

FIG. 3( a ) is a flowchart of a multi-directional intra-frame prediction coding method according to an embodiment of the present invention.

FIG. 3( b ) is a flowchart of a multi-directional intra-frame prediction decoding method according to an embodiment of the present invention.

FIG. 4 is a schematic diagram of reference pixel acquisition in a multi-directional intra prediction decoding method according to an embodiment of the present invention.

FIG. 5 is a schematic diagram of directional prediction in a multi-directional intra-frame prediction encoding method according to an embodiment of the present invention.

FIG. 6 is a schematic diagram of interpolation filtering in a multi-directional intra-frame prediction encoding method according to an embodiment of the present invention.

Fig. 7 is a schematic diagram of binarization according to an embodiment of the present invention.

FIG. 8( a ) is a schematic structural diagram of a multi-directional intra-frame prediction encoding device according to an embodiment of the present invention.

Fig. 8(b) is a schematic structural diagram of a multi-directional intra-frame prediction decoding device according to an embodiment of the present invention.

Detailed ways

Embodiments of the present invention will be described with reference to FIGS. 1-8.

In order to make the above objects, features and advantages more comprehensible, the present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

As shown in Figure 3(a), an intra-frame prediction coding method includes the following steps:

S31. For a prediction unit at the encoding end, initialize the current prediction mode to -1, and add 1 to the sequence number of the current prediction mode;

S32. Select reference pixels required for prediction for the intra prediction mode;

S33. Obtain the prediction value of the prediction unit by using the reference pixel prediction;

S34. Calculate the coding cost of the intra prediction mode, and select the current optimal coding mode;

S35. If the sequence number of the intra-frame prediction mode is greater than or equal to the set value, execute S36, otherwise skip to S31;

S36. Encode the optimal intra-frame prediction mode, and output it to a code stream.

As shown in Figure 3(b), an intra prediction decoding method includes the following steps:

S37. For an intra prediction unit at the decoding end, analyze and obtain an intra prediction mode of the current prediction unit;

S38. Select reference pixels required for prediction for the intra prediction mode;

S39. Obtain the prediction value of the prediction unit by using the reference pixel prediction.

For the encoding end, the set value of the intra prediction mode is 34, and its direction is shown in FIG. 5 . Figure 4 is a schematic diagram of reference pixel acquisition. Figure 6 is a schematic diagram of interpolation filtering. Figure 7 and Table 1 are the schematic diagram and scheme of binarization.

Table 1. Coding in Intra Coding Mode

IntraLumaPredMode Index 0 0 1 3 2 33 3 29 4 25 5 twenty one 6 17 7 13 8 9 9 2 10 8 11 12 12 16 13 20 14 twenty four 15 28 16 32 17 5 18 30 19 26 20 twenty two twenty one 18

twenty two 14 twenty three 10 twenty four 6 25 1 26 7 27 11 28 15 29 19 30 twenty three 31 27 32 31 33 4

Preferably, the current prediction direction of the reference pixel is extended through each pixel of the prediction unit to intersect with the encoded pixel, and the pixels involved around the extension line are extended.

Preferably, the pixel prediction value in one direction of the intra prediction block is obtained by filtering 3-4 pixels around the intersection point A of the straight line where the pixel position to be predicted and the straight line where the reference pixel is located by using the direction. The filter is a 4tap interpolation filter, and the coefficient of the filter is related to the distance between the reference pixel point and point A. The 4tap filter coefficient values are respectively [32-k, 64-k, 32+k, k]/128, where k is the distance from the reference pixel point on the left/upper side of point A to point A, and the value range of k is [0,32]. When point A is an integer pixel point, that is, k is 0 or 32, the 4tap filter degenerates into a 3tap filter, and the filter coefficient is [1,2,1].

As shown in Figure 8(a), it is a schematic structural diagram of a multi-directional intra-frame predictive encoding device according to an embodiment of the present invention. The device includes:

The encoding end reference pixel selection unit 81 is configured to select reference pixels required for prediction for an intra prediction mode of the prediction unit at the encoding end;

A prediction unit prediction value acquisition unit 82 at the coding end, configured to obtain a prediction value for each pixel in the prediction unit by using the intra prediction mode;

The encoding end cost function calculation unit 83 is used to calculate the encoding cost of encoding using the intra-frame prediction mode, so as to select the intra-frame prediction mode with the smallest encoding cost as the optimal prediction mode;

The intra prediction mode entropy coding unit 84 at the coding end is configured to perform binarization and entropy coding on the optimal prediction mode, and output to a code stream.

As shown in Figure 8(b), it is a schematic structural diagram of a multi-directional intra-frame prediction decoding device according to an embodiment of the present invention, and the device includes:

The intra-frame prediction mode analysis unit 85 at the decoding end is used to analyze the bits in the code stream to obtain the intra-frame prediction mode;

The reference pixel selection unit 86 at the decoding end is configured to select reference pixels required for prediction for an intra prediction mode of the prediction unit at the encoding end;

The prediction unit prediction value acquisition unit 87 at the decoding end is configured to obtain a prediction value for each pixel in the prediction unit by using the intra prediction mode.

Preferably, the reference pixel selection unit selects according to the needs of the current prediction mode. The current prediction direction is extended by each pixel of the prediction unit to intersect with the encoded pixel, and the pixels involved around the extension line are selected as reference pixels.

Preferably, the predicted value acquisition unit of the prediction unit is obtained by filtering 3 to 4 pixels around the intersection point A of the straight line where the pixel position to be predicted and the straight line where the reference pixel is located by using this direction. The filter is a 4tap interpolation filter, and the coefficient of the filter is related to the distance between the reference pixel point and point A. The 4tap filter coefficient values are respectively [32-k, 64-k, 32+k, k]/128, where k is the distance from the reference pixel point on the left/upper side of point A to point A, and the value range of k is [0,32]. When point A is an integer pixel point, that is, k is 0 or 32, the 4tap filter degenerates into a 3tap filter, and the filter coefficient is [1,2,1].

Preferably, the prediction mode entropy coding unit sorts the intra-frame prediction directions in order of occurrence probability from high to low, assigns shorter codewords to directions with high probability, and assigns relatively longer codewords to directions with low occurrence probability. Codeword. The allocation scheme of its code words is shown in Figure 1 and Table 1.

Preferably, the prediction mode analysis unit at the decoding end analyzes the bits in the code stream to obtain a binary code of the intra prediction mode, and obtains the corresponding intra prediction mode according to the binary code.

In yet another aspect, the embodiment of the present invention also provides a system for implementing multi-directional intra-frame predictive coding. The multi-directional intra-frame predictive coding system includes: an encoder, configured to obtain, for a prediction unit during the coding process, Its prediction values in all prediction modes, and calculate the encoding cost of each prediction mode, select the optimal encoding mode for entropy encoding, and output the code stream; the decoder is used to perform entropy decoding first in the decoding process to obtain its frame An intra prediction mode, using the intra prediction mode to predict the current prediction unit to obtain a prediction value.

Preferably, there are 34 types of intra-frame prediction modes tried by the encoder; reference pixels are selected according to the needs of the prediction mode during the prediction process; the prediction value is acquired using a 4tap filter, and the filter coefficient is [32-k, 64-k,32+k,k]/128; perform entropy coding on the binary code of the optimal prediction mode, the binary code adopts a truncated variable-length code, and the code length is determined according to the probability that the coding mode is the optimal coding mode .

Preferably, the decoder parses the intra-frame prediction mode in the code stream; using the intra-frame prediction mode, the prediction value is obtained by using the same method as that of the encoder.

Experimental results:

The embodiment of the present invention completes technical realization on RD1.0 (the reference software of AVS2 standard). In the experiment, the general test condition of AVS2 is adopted, the test length is 2s sequence, and all I frame configurations. The experimental platform is Intel(R) Xeon(R) CPU X5660 2.80GHZ 2.79GHZ23.9G memory. Table 2 shows the coding performance of the multi-directional intra-frame prediction coding method in the present invention. 1080p, WVGA, WQVGA, and 720p represent test sequences with resolutions of 1920x1080, 832x480, 416x240, and 1280x720, respectively. The measurement of coding performance adopts BD-rate, that is, the bit rate saving in the case of the same coding quality. According to the experimental results, using the above scheme of the embodiment of the present invention, compared with the original encoder, when the encoding quality is the same, the code rate can be saved by an average of 5.1%.

Table 2. Performance Comparison

Those skilled in the art can also understand that various illustrative logical blocks (illustrative logical blocks), units and steps listed in the embodiments of the present invention can be implemented by electronic hardware, computer software, or a combination of both. To clearly demonstrate the interchangeability of hardware and software, the various illustrative components, units and steps above have generically described their functions. Whether such functions are implemented by hardware or software depends on the specific application and overall system design requirements. Those skilled in the art may use various methods to implement the described functions for each specific application, but such implementation should not be understood as exceeding the protection scope of the embodiments of the present invention.

The various illustrative logic blocks or units described in the embodiments of the present invention can be implemented by general-purpose processors, digital signal processors, application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs) or other programmable logic devices, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to implement or operate the described functions. The general-purpose processor may be a microprocessor, and optionally, the general-purpose processor may also be any conventional processor, controller, microcontroller or state machine. A processor may also be implemented by a combination of computing devices, such as a digital signal processor and a microprocessor, multiple microprocessors, one or more microprocessors combined with a digital signal processor core, or any other similar configuration to accomplish.

The steps of the method or algorithm described in the embodiments of the present invention may be directly embedded in hardware, a software module executed by a processor, or a combination of both. The software modules may be stored in RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, hard disk, removable disk, CD-ROM or any other storage medium in the art. Exemplarily, the storage medium can be connected to the processor, so that the processor can read information from the storage medium, and can write information to the storage medium. Optionally, the storage medium can also be integrated into the processor. The processor and the storage medium can be set in the ASIC, and the ASIC can be set in the user terminal. Optionally, the processor and the storage medium may also be set in different components in the user terminal.

In one or more exemplary designs, the above functions described in the embodiments of the present invention may be implemented in hardware, software, firmware or any combination of the three. If implemented in software, the functions can be stored on or transmitted over as one or more instructions or code on a computer-readable medium. Computer-readable media includes computer storage media and communication media that facilitate transfer of a computer program from one place to another. Storage media may be any available media that can be accessed by a general purpose or special computer. For example, such computer-readable media may include, but are not limited to, RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other device that can be used to carry or store instructions or data structures and Other medium of program code in a form readable by a general-purpose or special-purpose computer, or a general-purpose or special-purpose processor. In addition, any connection is properly defined as a computer-readable medium, for example, if the software is transmitted from a web site, server, or other remote source via a coaxial cable, fiber optic computer, twisted pair, digital subscriber line (DSL) Or transmitted by wireless means such as infrared, wireless and microwave are also included in the definition of computer readable media. Disks and discs include compact discs, laser discs, optical discs, DVDs, floppy discs, and Blu-ray discs. Disks usually reproduce data magnetically, while discs usually reproduce data optically with lasers. Combinations of the above can also be contained on a computer readable medium.

Although the specific embodiments of the present invention have been described above, those skilled in the art should understand that these specific embodiments are only for illustration, and those skilled in the art can make the above-mentioned Various omissions, substitutions, and changes were made in the details of the methods and systems. For example, it is within the scope of the present invention to combine the above method steps so as to perform substantially the same function in substantially the same way to achieve substantially the same result. Accordingly, the scope of the invention is limited only by the appended claims.

Claims (10)

1. A method for encoding and decoding intra-frame prediction, comprising the following steps: Encoder: For an input intra-frame prediction unit, according to the set intra-frame prediction direction, select reference pixels required for performing intra-frame prediction in this direction; Using the reference pixels to predict the prediction unit according to a set prediction direction to obtain a pixel prediction value of the prediction unit, and the pixel prediction value is obtained by filtering the selected reference pixels; Traversing all prediction directions, entropy coding the optimal prediction direction; Decoder: Analyzing the intra prediction mode by using the inverse process of entropy coding at the encoding end; For an input intra-frame prediction unit, according to the set intra-frame prediction direction, select reference pixels required for performing intra-frame prediction in this direction; Using the reference pixels to predict the prediction unit according to the set prediction direction to obtain a pixel prediction value of the prediction unit, and the pixel prediction value is obtained by filtering the selected reference pixels. 2. The intra-frame prediction encoding and decoding method according to claim 1, wherein the set intra-frame prediction direction is extended by each pixel of the prediction unit to intersect with the encoded pixel, and the pixels involved around the extension line are selected as reference pixels. 3. The intra prediction encoding and decoding method according to claim 1, wherein 33 direction predictions and one DC prediction are used for one prediction unit. 4. The intra-frame prediction encoding and decoding method according to claim 3, wherein the prediction of the 33 directions is specifically to divide the angle deviating from the horizontal or vertical direction into 8 parts, and the angle alpha deviating from the horizontal or vertical direction =[3,7,12,18,24,31,38,45]/180*pi. 5. According to the described intra-frame prediction encoding and decoding method according to claim 4, it is characterized in that, adopting 1/32 direction accuracy, the pixel distance l=[2,4,7,10, 14,19,25,32]. 6. The intra-frame predictive encoding and decoding method according to claim 1, characterized in that the direction is obtained by filtering 3 to 4 pixels around the intersection of the straight line at the position of the pixel to be predicted and the straight line where the reference pixel is located. 7. According to the intra-frame prediction encoding and decoding method according to claim 6, it is characterized in that the filtering is specifically: 4tap interpolation filtering, and the filter coefficient values are respectively [32-k, 64-k, 32+k, k]/128, where k is the distance between the reference pixel point on the left or above of the intersection of the straight line at the pixel position to be predicted and the straight line where the reference pixel is located, and the intersection of the straight line at the pixel position to be predicted and the straight line where the reference pixel is located, and the value range of k is [ 0,32]. 8. According to the intra-frame prediction encoding and decoding method according to claim 6 or 7, it is characterized in that, when the intersection point of the straight line where the pixel position to be predicted and the straight line where the reference pixel is located is an integer pixel point, that is, k is 0 or 32 , the 4tap filter degenerates into a 3tap filter with filter coefficients [1,2,1]. 9. The intra-frame prediction encoding and decoding method according to any one of claims 1 to 7, wherein the entropy encoding specifically includes: performing binarization on the intra-frame prediction direction, and then entropy encoding, to frame The intra-prediction directions are sorted in descending order of occurrence probability, and shorter codewords are assigned to directions with higher probability, and relatively longer codewords are assigned to directions with lower probability of occurrence. 10. A multi-directional intra-frame prediction coding and decoding device, the device comprising: The reference pixel selection unit at the encoding end selects the reference pixels required for performing the prediction process according to the prediction mode; The prediction value acquisition unit of the prediction unit at the encoding end selects the reference pixel required to predict the current pixel value according to the prediction direction and the position of the current prediction pixel, and performs an interpolation filtering process to obtain the prediction value; The cost function calculation unit at the encoding end calculates the encoding cost of each prediction mode, and selects the prediction mode with the smallest encoding cost as the final encoding mode; The intra prediction mode entropy encoding unit at the encoding end performs entropy encoding on the optimal encoding mode obtained at the encoding end, and outputs a code stream; The intra-frame prediction mode entropy decoding unit at the decoding end uses the inverse process of entropy encoding at the encoding end to analyze the intra-frame prediction mode and obtain the intra-frame prediction mode from the code stream; The cost function calculation unit at the decoding end calculates the decoding cost of each prediction mode, and selects the prediction mode with the smallest decoding cost as the final decoding mode; The reference pixel selection unit at the decoding end selects the reference pixels required for performing the prediction process according to the prediction mode; The prediction value acquisition unit of the prediction unit at the decoding end selects the reference pixel required to predict the current pixel value according to the prediction direction and the position of the current prediction pixel, and performs an interpolation filtering process to obtain a prediction value.

Images