CN101854551A - Intra-frame prediction mode coding and decoding method and device - Google Patents

Abstract

The invention discloses an intra-frame prediction mode coding and decoding method and an intra-frame prediction mode coding and decoding device. In the coding and decoding method and the coding and decoding device, a cost function of available intra-frame prediction modes of a current block is calculated with pixel values of adjacent areas of the current block; and the available intra-frame prediction modes of the current block are sequenced according to values of the cost function, and an optimal intra-frame prediction mode of the current block is coded according to the sequencing information of the available intra-frame prediction modes of the current block. Through the technical scheme provided by the invention, re-established pixel information around the current block is made full use to accurately judge grain direction properties of the current block, and the intra-frame prediction mode is coded based on the judged grain direction properties, so the coding efficiency of intra-frame prediction mode information is effectively improved.

Description

Intra prediction mode decoding method and device

Technical field

The present invention relates to field of multimedia communication, relate in particular to the decoding method and the device of intra prediction mode information.

Background technology

Video and image coding technique be digital video and this important multimedia messages of image be widely used the basis and crucial.In video and image encoding, intracoded frame does not rely on coded frame, thereby can independently decode by decoded device, has as random access point and effectively prevents functions such as error propagation.Yet adopt this method, the intraframe coding compression ratio is very low, and coding information quantity is very big.In order to improve code efficiency, when encoding in the conducting frame, can carry out infra-frame prediction to encoding block with the information of having rebuild around the present encoding piece, utilize the spatial correlation of image to remove redundant.

At (the Video Coding H.264/Advanced of video encoding standard/advanced video coding standard H.264, H.264/AVC) and in the AVS video encoding standard, all adopted the infra-prediction techniques on the spatial domain, it is at the grain direction feature in the picture material, thereby designed a series of different intra prediction modes and reached more accurate prediction effect to adapt to different texture content, but the coding of intra prediction mode information has also caused the overhead on the code check simultaneously, especially under the situation of low code check, intra prediction mode information will occupy sizable ratio in all code stream information, at this moment, the high efficient coding to intra prediction mode seems particularly important.

In H.264/AVC, three types infra-frame prediction block size is arranged, i.e. I_16x16, I_8x8 and I_4x4 are for the I_16x16 type, have 4 kinds of predictive modes, as shown in Figure 1, for the I_4x4 type, shared 9 kinds of predictive modes, as shown in Figure 2, for I _ x8 type, equally with I_4x4 have 9 kinds of predictive modes, and the prediction direction corresponding with it is the same among the prediction direction of every kind of pattern and the I_4x4.

For I_16x16, its prediction mode information is resultant in can macro block (mb) type (mb_type) information in code stream, and transmits by absolute coding and in code stream for the prediction mode information of I_8x8 and I_4x4, and encryption algorithm as shown in Figure 3.

C is the current piece that is encoded among Fig. 3, and B and A are respectively the current block C left side and top reconstructed block, and ModeA, ModeB, ModeC represent the intra prediction mode corresponding sequence number (0-8) of piece A, B, C respectively.So, when the prediction mode information ModeC of coding current block C, utilize the B of encoding block and the actual coding pattern ModeB of the top A of encoding block and the model prediction value that ModeA generates piece C on its left side earlier, be called most possible pattern (Most Probable Mode, hereinafter to be referred as MPM), the generation method is:

MPM＝min(ModeA，ModeB)

If model prediction is (ModeC==MPM) accurately, be that piece C has adopted MPM as the actual prediction pattern really, then transmission 1 bit " 1 " conduct identifies in code stream, otherwise transmit 1 bit " 0 " earlier, transmit the predictive mode value that 3 bit informations come the actual employing of home block C again, because this moment, ModeC got rid of the possibility that equals MPM,, can represent with 3bit so have only 8 kinds of values possibilities.

By above analysis as can be seen, H.264/AVC the coding to intra prediction mode is fairly simple, has not made full use of available reference information, is in particular in following 2 aspects:

1) when the coding mode (promptly generating MPM) of prediction current block C, only utilized the prediction mode information of piece A and piece B, and do not made full use of the pixel value information of having rebuild in piece A and the piece B.

2) (when being ModeC ≠ MPM), 8 kinds of remaining patterns have been adopted 3 bit block codes, do not utilized any contextual information, also do not considered the probability distribution of 8 kinds of patterns of residue when the prediction misalignment.

After H.264/AVC, also there are some documents to propose improved frame predictive mode coding method.For example propose a kind of grain direction of utilizing current block to rebuild pixel region on every side among the motion JCTVC-A30 of Sony in nearest international video encoding standard group meeting and predicted the technology of the grain direction of current block, but this technology is when grain direction prediction misalignment, still adopted predictive mode coding method H.264/AVC, and the probability distribution that does not take into full account each predictive mode is uneven.

Therefore, H.264/AVC reach more existing improved intra prediction mode coding techniquess and all have the not high enough problem of coding efficiency, and this coding efficiency that will certainly influence infra-frame prediction integral body is especially at the coding efficiency that hangs down under the code check applicable cases.The key that improves the prediction mode information code efficiency just is to make full use of how better the information of having rebuild around the current block and accurately judges the grain direction that current block is most possible, and uses corresponding entropy coding method according to the probability distribution of residue pattern when the prediction misalignment.

Summary of the invention

The objective of the invention is at the deficiencies in the prior art, a kind of more efficient frame predictive mode coding method is provided.

For this reason, the invention provides a kind of frame predictive mode coding method, this method is utilized the cost function of the intra prediction mode that the calculated for pixel values current block of current block adjacent area can use, according to the size of cost function value to current block can with intra prediction mode sort, according to current block can with the sequencing information of intra prediction mode the optimum frame inner estimation mode of current block is encoded.

The cost function of the intra prediction mode that the described calculated for pixel values current block that utilizes the current block adjacent area can be used is realized in the following manner, partial pixel value in the current block adjacent area is set at reference value, for every kind of intra prediction mode is set a grain direction, in the current block adjacent area, choose the pixel sample values corresponding according to the grain direction of the intra prediction mode of setting and be set at desired value, utilize distortion between reference value and the desired value to obtain the cost function value of intra prediction mode with reference value.

Described according to current block can with the sequencing information of intra prediction mode the optimum frame inner estimation mode of current block encoded be meant the optimum frame inner estimation mode of the intra prediction mode that cost function value is minimum or maximum as current block, optimum frame inner estimation mode information does not write among the code stream.

Described according to current block can with intra prediction mode sequencing information to the optimum frame inner estimation mode of current block encode be meant with the optimum frame inner estimation mode of current block current block can with the ordering of intra prediction mode in ranking index encode, and write among the code stream.

Described according to current block can with the sequencing information of intra prediction mode the optimum frame inner estimation mode of current block encoded be meant whether the optimum frame inner estimation mode with two metasymbol f sign current block is the intra prediction mode of cost function value minimum, if the optimum frame inner estimation mode of current block is not the intra prediction mode of cost function value minimum, so the optimum frame inner estimation mode index of current block is encoded.

The present invention also provides a kind of intra prediction mode coding/decoding method, this method is utilized the cost function of the intra prediction mode that the calculated for pixel values current block of current block adjacent area can use, according to the size of cost function value to current block can with intra prediction mode sort, according to current block can with the sequencing information of intra prediction mode the optimum frame inner estimation mode of current block is decoded.

The cost function of the intra prediction mode that the described calculated for pixel values current block that utilizes the current block adjacent area can be used is realized in the following manner, partial pixel value in the current block adjacent area is set at reference value, for every kind of intra prediction mode is set a grain direction, in the current block adjacent area, choose the pixel sample values corresponding according to the grain direction of the intra prediction mode of setting and be set at desired value, utilize distortion between reference value and the desired value to obtain the cost function value of intra prediction mode with reference value.

Described according to current block can with the sequencing information of intra prediction mode the optimum frame inner estimation mode of current block decoded be meant the optimum frame inner estimation mode of the intra prediction mode that cost function value is minimum or maximum as current block, optimum frame inner estimation mode information is not obtained from code stream.

Described according to current block can with intra prediction mode sequencing information to the optimum frame inner estimation mode of current block decode be meant to the optimum frame inner estimation mode of current block current block can with the ordering of intra prediction mode in ranking index decode, and obtain corresponding optimum frame inner estimation mode according to the index of decoding gained.

Described according to current block can with the sequencing information of intra prediction mode the optimum frame inner estimation mode of current block decoded be meant, from code stream, obtain earlier two metasymbol f, whether with the optimum frame inner estimation mode of judging current block is the intra prediction mode of cost function value minimum, if the optimum frame inner estimation mode of current block is not the intra prediction mode of cost function value minimum, so the optimum frame inner estimation mode index of current block is decoded, and obtain corresponding optimum frame inner estimation mode according to the index of decoding gained.

The present invention also provides a kind of intra prediction mode code device, and it comprises:

Intra prediction mode cost function value computing unit, the cost function value of the intra prediction mode that the calculated for pixel values generation current block of this unit by using current block adjacent area can be used;

Intra prediction mode cost function value sequencing unit, this unit according to the size of the cost function value of each intra prediction mode to current block can with intra prediction mode sort;

Optimum frame inner estimation mode coding unit, this unit according to current block can with the sequencing information of intra prediction mode the optimum frame inner estimation mode of current block is encoded.

The present invention also provides a kind of intra prediction mode decoding device, and it comprises:

Intra prediction mode cost function value computing unit, the cost function value of the intra prediction mode that the calculated for pixel values generation current block of this unit by using current block adjacent area can be used;

Intra prediction mode cost function value sequencing unit, this unit according to the size of the cost function value of each intra prediction mode to current block can with intra prediction mode sort;

Optimum frame inner estimation mode decoding unit, this unit according to current block can with the sequencing information of intra prediction mode the optimum frame inner estimation mode of current block is decoded.

The invention has the beneficial effects as follows: the present invention is when coded frame inner estimation mode information, made full use of the Pixel Information of having rebuild around the current block, to judge the grain direction characteristic of current block more exactly, and intra prediction mode is encoded based on the grain direction characteristic of being judged, effectively improve the code efficiency of intra prediction mode information, thereby improved the overall performance of intraframe coding.

Description of drawings

Fig. 1 is the H.264 middle 16x16 intra prediction mode schematic diagram of prior art;

Fig. 2 is the H.264 middle 4x4 intra prediction mode schematic diagram of prior art;

Fig. 3 is the H.2644x4 piecemeal model prediction coding techniques schematic diagram of prior art;

Fig. 4 is the reference sample schematic diagram of having rebuild around the current block of the embodiment of the invention;

Fig. 5 is that the Suo Beier direction of the embodiment of the invention detects the operator schematic diagram;

Fig. 6 is the intra prediction mode code device schematic diagram of the embodiment of the invention;

Fig. 7 is the intra prediction mode decoding device schematic diagram of the embodiment of the invention.

Embodiment

For making the purpose, technical solutions and advantages of the present invention clearer, the present invention is described in further detail below in conjunction with accompanying drawing.

Embodiment 1

First execution mode of the present invention relates to a kind of frame predictive mode coding method.

Present embodiment was divided into for 3 steps in the specific implementation method of coding side:

The first step is utilized the cost function of rebuilding the intra prediction mode that the calculated for pixel values current block can use of adjacent area around the current block, is used as judging the foundation of current block grain direction with this.A kind of algorithm examples of calculation cost function is described below:

As shown in Figure 4, this algorithm examples utilizes the pixel value of reconstruction (under the situation that can get) of the adjacent triplex row of the adjacent triplex row and the left side above the current block to calculate the cost function of each available intra prediction mode of current block.Because when picture material has grain direction, the variation of pixel value or fluctuation are very little on grain direction, so this algorithm examples utilizes along the cost function value of the big or small conduct of the mean difference of adjacent pixel values on a certain direction corresponding to the intra prediction mode of this direction.Because natural image exists the continuity of grain direction, so can utilize the grain direction of adjacent area that the grain direction of current block is estimated, so the employed cost function of this algorithm examples can be used to weigh the texture power of current block on all directions.

Be 4x4 below with the coded block size, available intra prediction mode for the vertical pattern (Vertical Mode) shown in Fig. 4, tiltedly bottom right pattern (DownRight Mode), vertically take over pattern (VerticalRightMode) and a kind of nondirectional direct current predictive mode (DC Mode) totally 4 kinds of intra prediction modes be example, to how to be specifically described with this algorithm examples calculation cost function.The cost function calculation of this moment need be used 8 reference pixel samples, rebuilds pixel samples R1～R8 for promptly adjacent with left margin with the current block coboundary 8, as shown in Figure 4.Find the nearest Pi of reconstruction pixel samples on its direction according to the directivity of each intra prediction mode then with reference sample Ri, i=1,2 ..., 8, as shown in Figure 4, illustrated the Pi of three intra prediction direction except that the DC pattern with line.So, the cost function value that can be calculated each intra prediction mode except that the DC pattern by the difference between Ri and the Pi (distortion) (is designated as Wi, i is the predictive mode index), cost function value herein promptly is the cymomotive force of each infra-frame prediction Russia pattern on its prediction direction, as shown in the formula:

$W_{\mathrm{IPM}\_\mathrm{index}}=\underset{i=1}{\overset{8}{\mathrm{\Σ}}}{({\mathrm{Pi}}_{\mathrm{IPM}\_\mathrm{index}}-\mathrm{Ri})}^2;$ IPM_index≠DC

For the DC pattern, in this algorithm examples the definition its cost function as shown in the formula:

$W_{\mathrm{DC}}=\underset{i=1}{\overset{8}{\mathrm{\Σ}}}{\mathrm{Ri}}^2-{\left(\underset{i=1}{\overset{8}{\mathrm{\Σ}}}\mathrm{Ri}\right)}^2/8$

Need to prove that above-mentioned algorithm examples is the special case that cost function calculation realizes, the cost function calculation method that is adopted during practical application includes but not limited to above-mentioned algorithm examples.Even if use above-mentioned algorithm, wherein related coded block size and shape, used reference pixel sample size and position, all relevant parameters such as concrete formula that calculate cymomotive force also all can change according to the needs of practical application, are not limited to special case herein.

Second the step, according to the cost function value size that obtains in the first step to current block can with intra prediction mode sort.

For example, common 7 the available intra prediction modes of current block, the cost function value of each mode computation gained is as shown in table 1:

7 kinds of intra prediction mode cost function value of table 1 example

The pattern numbering	?0	??1	??2	??3	??4	??5	??6
								Cost function value	?200	??150	??230	??170	??210	??160	??190

So, carry out obtaining after from small to large the ordering mode sequence as shown in table 2 according to the size of cost function value:

7 kinds of intra prediction mode ranking results of table 2 example

Ranking index	?1	??2	??3	??4	??5	??6	??7
								The pattern numbering	?1	??5	??3	??6	??0	??4	??2

Need to prove, be a kind of implementation method according to from small to large rank order herein, can select the clooating sequence that is fit to when practical application is of the present invention as required.

The 3rd step, the current block that obtains according to second step can with the sequencing information of intra prediction mode the optimum frame inner estimation mode of current block is encoded." the optimum frame inner estimation mode of current block " of the present invention is meant the final intra prediction mode that adopts of current block.A kind ofly be described below according to the encode algorithm examples of current block optimum frame inner estimation mode information of predictive mode sequencing information:

In the intra prediction mode after directly will sorting, the predictive mode of cost function value minimum is as the optimum frame inner estimation mode (the promptly final predictive mode that adopts) of current block, need not to write in code stream prediction mode information, decoding end can be by deriving the optimum frame inner estimation mode that current block adopts with coding side identical operations step.

For example, if the cost function of intra prediction mode adopts the algorithm examples in the above-mentioned first step, then the size of cost function value has reflected the degree of fluctuation of every kind of intra prediction mode on its prediction direction, the more for a short time grain direction that is illustrated on its prediction direction of degree of fluctuation is strong more, therefore the predictive mode of selecting the cost function value minimum has selected the predictive mode of most possible representative current block textural characteristics to come current block is encoded as the optimum frame inner estimation mode exactly.

In addition, during this algorithm examples of practical application, also can select predictive mode with the cost function value maximum as current block optimum frame inner estimation mode, its reason behind and motivation also can be according to concrete application demands and different.

Need to prove, above-mentioned algorithm examples is a special case in the embodiment of the present invention, when practical application is of the present invention, including but not limited to this, more encryption algorithm example will further specify in other embodiments of the invention to optimum frame inner estimation mode Methods for Coding.

Embodiment 2

Second execution mode of the present invention relates to a kind of intra prediction mode coding/decoding method.

Present embodiment also was divided into for 3 steps in the concrete real method of decoding end, and is corresponding with the performing step of embodiment 1 coding side respectively, specifically describes as follows:

The first step is utilized the cost function of rebuilding the intra prediction mode that the calculated for pixel values current block can use of adjacent area around the current block, is used as judging the foundation of current block grain direction with this.

The cost function value of this step is calculated implementation method need be in full accord with coding side, to guarantee the cost function value unanimity of the intra prediction mode that current block that the encoding and decoding end is obtained can be used.The specific implementation method is referring to the description of coding side part among the embodiment 1.

Second the step, according to the cost function value size that obtains in the first step to current block can with intra prediction mode sort.

The ordering implementation method of this step need be in full accord with coding side, with the predictive mode sequencing information unanimity that guarantees that the encoding and decoding end is obtained.The specific implementation method is referring to the description of coding side part among the embodiment 1.

The 3rd step, the current block that obtains according to second step can with the sequencing information of intra prediction mode the optimum frame inner estimation mode of current block is decoded.

The optimum frame inner estimation mode coding/decoding method of this step need be corresponding with the coding method that coding side adopts.Adopting the encryption algorithm example in above-mentioned the 3rd step with coding side is example, in the intra prediction mode after decoding end directly will sort this moment, the predictive mode of cost function value minimum is judged to be the optimum frame inner estimation mode (the promptly final predictive mode that adopts) of current block, need not to read from code stream prediction mode information.With this predictive mode current block is carried out follow-up prediction and decodes getting final product then.

If coding side adopts other encryption algorithm, then the decoding algorithm of decoding end also needs to do corresponding adjustment, and more code decode algorithm example will further specify in other embodiments of the invention.

Embodiment 3

The 3rd execution mode of the present invention relates to a kind of frame predictive mode coding method.

The overall flow of present embodiment coding side can be with reference to the embodiment of the invention 1, and difference is the method difference of the cost function of the intra prediction mode that the calculating current block can be used in the coding side first step.Specifically describe as follows:

In the present embodiment, at first the Suo Beier direction that each reference image vegetarian refreshments (the triangle sample point among Fig. 4 and each Ri) of having rebuild around the current block shown in Figure 4 on the reference pixel zone is used as shown in Figure 5 detects operator, with horizontal texture intensity and the vertical texture strength value of calculating each reference pixel, form a grain direction intensity vector, be designated as Ri (x, y), i=1,2 ..., N.Wherein Ri represents i the reference pixel of having rebuild, and N is for participating in the reference pixel number of samples of calculating, and x and y are respectively on Ri and calculate horizontal texture intensity level and the vertical texture strength value that obtains with the Suo Beier operator.Then to the grain direction intensity vector of all reference pixels ask mean deviation carry out normalization (mould of vector is scaled to 1) obtain a vectorial R who is used to characterize the whole grain direction of current block adjacent area (x, y), as shown in the formula:

$R^{\′}(x,y)=\left[\frac{1}{N}\underset{i=1}{\overset{N}{\mathrm{\Σ}}}{R}_i(x,y)\right]$

R(x，y)＝R′(x，y)/||R′(x，y)||

Wherein || and R ' (x, y) || expression R ' (x, mould y).

Next this algorithm examples will be according to the pairing direction of each available frame inner estimation mode of current block, for each predictive mode determines that a normalized vector is to describe its directivity.Available frame inner estimation mode with current block is that horizontal pattern, vertical pattern and oblique bottom right mode 3 kind predictive mode are example, and the normalization directivity vector of these three kinds of predictive mode correspondences is as shown in table 3 respectively:

The directivity vector of three kinds of intra prediction mode correspondences of table 3

At last, the cost function value of each predictive mode is vectorial R (x, Euclidean distance y) of the whole grain direction of pairing directivity vector of this predictive mode and sign current block adjacent area.

For example, if R (x, y)=(0.9,0.1), then the cost function calculation of 3 kinds of intra prediction modes in the table 3 is as follows:

$\left|\right|\left(\mathrm{0.9,0.1}\right)-(\sqrt{2}/2,\sqrt{2}/2)\left|\right|=\sqrt{{(0.9-\sqrt{2}/2)}^2+{(0.1-\sqrt{2}/2)}^2}\≈\sqrt{0.41}$

The encoding and decoding end all adopts above-mentioned algorithm examples to calculate the cost function value of each intra prediction mode that current block can use.

Therefore present embodiment at first obtains the directivity vector of current block peripheral region based on the Suo Beier operator, then with the Euclidean distance of this directivity vector directivity vector corresponding with each intra prediction mode as cost function value.

Need to prove, each related selection of parameter is a special case of present embodiment in the method for each predictive mode cost function value of aforementioned calculation, around the wherein related calculating current block the pairing directivity vector of directivity vector, various intra prediction mode of reconstruction regions, how to utilize around the current block the directivity vector of the directivity vector of reconstruction regions and intra prediction mode to obtain key element such as cost function value all can to change, be not limited to above special case according to practical application request.For example, when generating the directivity vector of current block peripheral region, can detect operator (for example Robert's operator) with other directions and detect the directivity of each reference image vegetarian refreshments and pick out some reference image vegetarian refreshments that are considered to interference signal (for example its vector mould is less), generate the directivity vector in whole zone with remaining reference image vegetarian refreshments; And for example when utilizing around the current block that the directivity vector of the directivity vector of reconstruction regions and intra prediction mode has obtained cost function value, can generate cost function value with other tolerance such as mahalanobis distance of two vectors.

Embodiment 4

The 4th execution mode of the present invention relates to a kind of intra prediction mode coding/decoding method.

The overall flow of present embodiment decoding end can be with reference to the embodiment of the invention 2, and difference is the method difference of the cost function of the intra prediction mode that the calculating current block can be used in the decoding end first step.The cost function value calculating method that decoding end adopted in the present embodiment is identical with the cost function value calculating method that coding side adopted described in the embodiment 3, and the specific implementation method is referring to embodiment 3.

Embodiment 5

The 5th execution mode of the present invention relates to a kind of frame predictive mode coding method.

The overall flow of present embodiment coding side can be with reference to the embodiment of the invention 1, difference be coding side the 3rd in the step according to current block can with the sequencing information of the intra prediction mode method difference of the optimum frame inner estimation mode of current block being carried out encoding and decoding.Specifically describe as follows:

The coding side of present embodiment is when the optimum frame inner estimation mode of coding current block, at first obtain the ranking index of optimum frame inner estimation mode correspondence in the ordering of the intra prediction mode that the current block of generation can be used from second step (referring to embodiment 1), then this index value is encoded.

With 7 kinds of pattern orderings in the table 2 is example, and the optimum frame inner estimation mode of supposing current block is a pattern 0, and then as known from Table 2, the ranking index of pattern 0 correspondence is 5, so coding side is encoded to ranking index 5.

When the coding and sorting order index, can use various entropy codings, for example variable-length encoding, the H.264/AVC CABAC in (context adaptive binary arithmetic coding) etc.

With the variable-length encoding is example, after sorting according to cost function value, can expect that ranking index can have certain specific character as the probability distribution of optimum frame inner estimation mode, and this characteristic depends on the computational methods of employed cost function value.For example, if during the possibility (the big more possibility of cost function value is big more) that the direction that the cost function value of predictive mode has characterized this predictive mode and current block grain direction are mated, after predictive mode sorted from big to small by cost function value, the pattern that ranking index is more little was possible more as the optimum frame inner estimation mode.In this case, can select encode 7 kinds of predictive modes in the previous examples of prefix variable length code table as shown in table 4 for use, if the optimum frame inner estimation mode of current block is a pattern 0, its corresponding ranking index is 5, then uses code word " 11110 " that this pattern information is encoded.

Table 4 prefix variable length code table

Ranking index	Code word
		??1	??0
??2	??10
		??3	??110
??4	??1110
		??5	??11110
??6	??111110
		??7	??1111110

Be example with CABAC again, suppose that equally current block has 7 available intra prediction modes, when then according to the ranking results of predictive mode optimum frame inner estimation mode information being encoded, 6 binary probabilistic models can be set, cataloged procedure is described below:

A) index of establishing probabilistic model is ctx, and is initialized as 0, i.e. ctx=0;

BestIPM=optimum frame inner estimation mode;

The highest intra prediction mode of CurIPM=possibility;

b)while(1)

{

if(BestIPM＝＝CurIPM)

{

The binary arithmetic coding (' 1 ', ctx);

break；

}

else

{

The binary arithmetic coding (' 0 ', ctx);

ctx＝ctx+1；

The highest intra prediction mode of the next possibility of CurIPM=;

if(ctx＝＝8)

break；

}

}

Need to prove, above-mentioned according to current block can with the sequencing information of intra prediction mode concrete grammar that the optimum frame inner estimation mode of current block is encoded in each related selection of parameter be a kind of special case of present embodiment, the method of ranking index of optimum frame inner estimation mode of wherein encoding can change according to the demand of practical application, includes but not limited to above-mentioned special case.

Embodiment 6

The 6th execution mode of the present invention relates to a kind of intra prediction mode coding/decoding method.

The overall flow of present embodiment decoding end can be with reference to the embodiment of the invention 2, difference be decoding end the 3rd in the step according to current block can with the sequencing information of the intra prediction mode method difference of the optimum frame inner estimation mode of current block being carried out encoding and decoding.Specifically describe as follows:

The decoding end of present embodiment need use current block that the method corresponding with coding side obtain according to second step can with the sequencing information of intra prediction mode the optimum frame inner estimation mode of current block is decoded.

Adopting variable-length encoding with coding side is example (referring to the variable-length encoding example among the embodiment 5), suppose still to use the predictive mode ranking results of table 2 and the variable length coding table of table 4, then decoding end is when the intra prediction mode of decoding current block, at first from code stream, obtain the code word of the pairing ranking index of optimum frame inner estimation mode of current block, tabling look-up to decode according to table 4 then obtains the pairing ranking index of code word, finds out the pairing intra prediction mode of this ranking index according to table 2 at last.For example, the code word that obtains from code stream is " 11110 ", and then as shown in Table 4, the ranking index of this code word correspondence is 5, and more as shown in Table 2, the optimum frame inner estimation mode of current block is a pattern 0.

Adopting CABAC with coding side again is power (referring to the coding of the CABAC among the embodiment 5 example), suppose to adopt the front to describe coding side CABAC coding method, then decoding end can be provided with 6 binary probabilistic models equally when the intra prediction mode of decoding current block, and decode procedure is described below:

A) index of establishing probabilistic model is ctx, and is initialized as 0, i.e. ctx=0;

BestIPM represents the optimum frame inner estimation mode;

The highest intra prediction mode of CurIPM=possibility;

b)while(1)

{

If (binary arithmetic coding (ctx)==1)

{

BestIPM＝CurIPM；

break；

}

else

{

ctx＝ctx+1；

The highest intra prediction mode of the next possibility of CurIPM=;

if(ctx＝＝8)

{

BestIPM＝CurIPM；

break；

}

}

}

Need to prove, above-mentioned according to current block can with the sequencing information of intra prediction mode concrete grammar that the optimum frame inner estimation mode of current block is decoded in each related selection of parameter be a kind of special case of present embodiment, the method of ranking index of optimum frame inner estimation mode of wherein decoding can change according to the demand of practical application, includes but not limited to above-mentioned special case.

Embodiment 7

The 7th execution mode of the present invention relates to a kind of frame predictive mode coding method.

The overall flow of present embodiment coding side can be with reference to the embodiment of the invention 5, difference is that coding side is before the ranking index of the optimum frame inner estimation mode of the current block of encoding with method as described in example 5 above, first one two metasymbol of coding, whether the optimum frame inner estimation mode that is used to identify current block is the intra prediction mode of cost function value minimum.If then need not next code; Otherwise, according to the method described in the embodiment 5 ranking index of the optimum frame inner estimation mode of current block is encoded again.

Embodiment 8

The 8th execution mode of the present invention relates to a kind of intra prediction mode coding/decoding method.

The overall flow of present embodiment decoding end can be with reference to the embodiment of the invention 6, difference is that decoding end is before the ranking index of the optimum frame inner estimation mode of the current block of decoding with method as described in example 6 above, whether one two metasymbol of decoding is the intra prediction mode of cost function value minimum with the optimum frame inner estimation mode of judging current block earlier.If then need not subsequent decoding; Otherwise, according to the method described in the embodiment 6 ranking index of the optimum frame inner estimation mode of current block is decoded again.

Embodiment 9

The 9th execution mode of the present invention relates to a kind of intra prediction mode code device.

As shown in Figure 6, the described code device of present embodiment comprises intra prediction mode cost function value computing unit, intra prediction mode cost function value sequencing unit and optimum frame inner estimation mode coding unit.Wherein, intra prediction mode cost function value computing unit utilizes the calculated for pixel values of current block adjacent area to generate the cost function value (the specific implementation method is referring to embodiment 1 and embodiment 3) of the intra prediction mode that current block can use; Intra prediction mode cost function value sequencing unit according to the size of the cost function value of each intra prediction mode to current block can with intra prediction mode sort (the specific implementation method is referring to embodiment 1); Optimum frame inner estimation mode coding unit according to current block can with the sequencing information of intra prediction mode to the optimum frame inner estimation mode of current block encode (the specific implementation method is referring to embodiment 1, embodiment 5 and embodiment 7).

Embodiment 10

The tenth execution mode of the present invention relates to a kind of intra prediction mode decoding device.

As shown in Figure 7, the described decoding device of present embodiment comprises intra prediction mode cost function value computing unit, intra prediction mode cost function value sequencing unit and optimum frame inner estimation mode decoding unit.Wherein, intra prediction mode cost function value computing unit utilizes the calculated for pixel values of current block adjacent area to generate the cost function value (the specific implementation method is referring to embodiment 2 and embodiment 4) of the intra prediction mode that current block can use; Intra prediction mode cost function value sequencing unit according to the size of the cost function value of each intra prediction mode to current block can with intra prediction mode sort (the specific implementation method is referring to embodiment 2); Optimum frame inner estimation mode decoding unit according to current block can with the sequencing information of intra prediction mode to the optimum frame inner estimation mode of current block decode (the specific implementation method is referring to embodiment 2, embodiment 6 and embodiment 8).

The present invention is when coded frame inner estimation mode information, made full use of the Pixel Information of having rebuild around the current block, to judge the grain direction characteristic of current block more exactly, and intra prediction mode is encoded based on the grain direction characteristic of being judged, effectively improve the code efficiency of intra prediction mode information, thereby improved the overall performance of intraframe coding.

Though pass through with reference to some of the preferred embodiment of the invention, the present invention is illustrated and describes, but those of ordinary skill in the art should be understood that and can do various changes to it in the form and details, and without departing from the spirit and scope of the present invention.

Claims (12)

1. frame predictive mode coding method, it is characterized in that: the cost function that utilizes the intra prediction mode that the calculated for pixel values current block of current block adjacent area can use, according to the size of cost function value to current block can with intra prediction mode sort, according to current block can with the sequencing information of intra prediction mode the optimum frame inner estimation mode of current block is encoded.

2. according to a kind of frame predictive mode coding method described in the claim 1, it is characterized in that: the cost function of the intra prediction mode that the described calculated for pixel values current block that utilizes the current block adjacent area can be used is realized in the following manner, partial pixel value in the current block adjacent area is set at reference value, for every kind of intra prediction mode is set a grain direction, in the current block adjacent area, choose the pixel sample values corresponding according to the grain direction of the intra prediction mode of setting and be set at desired value, utilize distortion between reference value and the desired value to obtain the cost function value of intra prediction mode with reference value.

3. according to a kind of frame predictive mode coding method described in the claim 1, it is characterized in that: described according to current block can with the sequencing information of intra prediction mode the optimum frame inner estimation mode of current block encoded be meant the optimum frame inner estimation mode of the intra prediction mode that cost function value is minimum or maximum as current block, optimum frame inner estimation mode information does not write among the code stream.

4. according to a kind of frame predictive mode coding method described in the claim 1, it is characterized in that: described according to current block can with intra prediction mode sequencing information to the optimum frame inner estimation mode of current block encode be meant with the optimum frame inner estimation mode of current block current block can with the ordering of intra prediction mode in ranking index encode, and write among the code stream.

5. according to a kind of frame predictive mode coding method described in the claim 1, it is characterized in that: described according to current block can with the sequencing information of intra prediction mode the optimum frame inner estimation mode of current block encoded be meant whether the optimum frame inner estimation mode with two metasymbol f sign current block is the intra prediction mode of cost function value minimum, if the optimum frame inner estimation mode of current block is not the intra prediction mode of cost function value minimum, so the optimum frame inner estimation mode index of current block is encoded.

6. intra prediction mode coding/decoding method, it is characterized in that: the cost function that utilizes the intra prediction mode that the calculated for pixel values current block of current block adjacent area can use, according to the size of cost function value to current block can with intra prediction mode sort, according to current block can with the sequencing information of intra prediction mode the optimum frame inner estimation mode of current block is decoded.

7. according to a kind of intra prediction mode coding/decoding method described in the claim 2, it is characterized in that: the cost function of the intra prediction mode that the described calculated for pixel values current block that utilizes the current block adjacent area can be used is realized in the following manner, partial pixel value in the current block adjacent area is set at reference value, for every kind of intra prediction mode is set a grain direction, in the current block adjacent area, choose the pixel sample values corresponding according to the grain direction of the intra prediction mode of setting and be set at desired value, utilize distortion between reference value and the desired value to obtain the cost function value of intra prediction mode with reference value.

8. according to a kind of intra prediction mode coding/decoding method described in the claim 2, it is characterized in that: described according to current block can with the sequencing information of intra prediction mode the optimum frame inner estimation mode of current block decoded be meant the optimum frame inner estimation mode of the intra prediction mode that cost function value is minimum or maximum as current block, optimum frame inner estimation mode information is not obtained from code stream.

9. according to a kind of intra prediction mode coding/decoding method described in the claim 2, it is characterized in that: described according to current block can with intra prediction mode sequencing information to the optimum frame inner estimation mode of current block decode be meant to the optimum frame inner estimation mode of current block current block can with the ordering of intra prediction mode in ranking index decode, and obtain corresponding optimum frame inner estimation mode according to the index of decoding gained.

10. according to a kind of intra prediction mode coding/decoding method described in the claim 2, it is characterized in that: described according to current block can with the sequencing information of intra prediction mode the optimum frame inner estimation mode of current block decoded be meant, from code stream, obtain earlier two metasymbol f, whether with the optimum frame inner estimation mode of judging current block is the intra prediction mode of cost function value minimum, if the optimum frame inner estimation mode of current block is not the intra prediction mode of cost function value minimum, so the optimum frame inner estimation mode index of current block is decoded, and obtain corresponding optimum frame inner estimation mode according to the index of decoding gained.

11. an intra prediction mode code device is characterized in that, comprises:

Intra prediction mode cost function value computing unit, the cost function value of the intra prediction mode that the calculated for pixel values generation current block of this unit by using current block adjacent area can be used;

Intra prediction mode cost function value sequencing unit, this unit according to the size of the cost function value of each intra prediction mode to current block can with intra prediction mode sort;

Optimum frame inner estimation mode coding unit, this unit according to current block can with the sequencing information of intra prediction mode the optimum frame inner estimation mode of current block is encoded.

12. an intra prediction mode decoding device is characterized in that, comprises:

Intra prediction mode cost function value computing unit, the cost function value of the intra prediction mode that the calculated for pixel values generation current block of this unit by using current block adjacent area can be used;

Intra prediction mode cost function value sequencing unit, this unit according to the size of the cost function value of each intra prediction mode to current block can with intra prediction mode sort;

Optimum frame inner estimation mode decoding unit, this unit according to current block can with the sequencing information of intra prediction mode the optimum frame inner estimation mode of current block is decoded.

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