CN1226882C - Two stage predictive coding method based on sampling macroblock structure in video frequency signal - Google Patents

Abstract

The present invention belongs to the technical field of video coding and decoding in signal processing, which relates to a two-stage predictive code method based on a sampling micro block structure in a video signal. A predictive basic unit in a video signal code of the present invention is macro blocks composed of 16 pixel *16 pixel squares, and the macro blocks comprise an original macro block and a sampling macro block, wherein the original macro block is a continuous 16 pixel * 16 pixel square; the sampling macro block is a 16 pixel *16 pixel square which carries out horizontal or perpendicular 1/2 sampling for the original macro block and is obtained through new array. The two-stage predictive code method of the present invention uses four kinds of sampling macro blocks composed of the 16 pixel * 16 pixel squares as the predictive basic unit, the four kinds of sampling macro blocks form six kinds of code macro block types and three kinds of code structures, and any kind of the three kinds of code structures is used for carrying out code and decoding. The predictive code structure of the present invention can be combined with other different code technology to effectively improve the compression efficiency of the video signal.

Description

In a kind of vision signal based on the sampling macroblock structure the two-stage forecasting coding method

Technical field the invention belongs to the video coding and decoding technology field in the signal processing.

H.261 video encoding standard that background technology is traditional such as ITU formulate, H.263, and H.263+, H.264 the MPEG-1 that organizes to set up of the MPEG of standard and ISO, MPEG-2, MPEG-4 etc. be based upon hybrid coding, promptly on the Hybrid Coding framework.So-called hybrid encoding frame is a kind of incorporation time space video image code method, and this method comprises: carry out in the frame earlier, the prediction of interframe, to eliminate the correlation of time-domain; Then original picture and the residual error that predicts the outcome are carried out two-dimensional transform (adopting discrete cosine transform or other linear transformation), eliminate spatial coherence; Carry out entropy coding then, remove statistical redundancy.

In order to improve compression efficiency of video signal, prediction is a most important core technology in the video encoding standard, and Forecasting Methodology generally is divided into infra-frame prediction and inter prediction.

In above-mentioned video encoding standard, macro block (16 * 16 image pixel pieces) is the base unit of prediction and encoding and decoding.Macro block can be decomposed into 16 * 16, or two 8 * 16, or two 16 * 8, or four 8 * 8, or a plurality of 8 * 4,4 * 8,4 * 4 wait some little rectangular blocks.Inter-frame prediction method is with the original picture of these rectangular block sizes (image of original input), it is the original picture piece, carry out estimation in reference picture (being used as the image of reference in the reconstruction frames of former coding), the optimum Match picture block that just obtains the original picture piece is as predicting the outcome.Intra-frame prediction method is an encoded rectangular block around the rectangular block that utilization needs to encode in current encoded frame, and the rectangular block of needs coding is predicted that the prediction rectangular block conduct that obtains predicts the outcome.

In video encoding standard, mainly there are four kinds of predictive coding methods at present.Because the input of vision signal can be divided into line by line scan with interleaved.The vision signal of lining by line scan is called frame image, and interleaved vision signal is called field pattern and resembles.Macro block in the frame image is the frame macro block, and the macro block during field pattern resembles is a macro block.The predictive coding method that with the frame macro block is unit is frame predictive coding method (being called for short the frame coding), is that the predictive coding method of unit is named a field prediction coding method (be called for short encode) with the field macro block.H.261, H.263, H.263+, the MPEG-1 that organizes to set up of the MPEG of standard and ISO H.264, MPEG-2, the frame coding that MPEG-4 standard etc. all comprises, MPEG-2, H.264 MPEG-4 also comprises a coding.In the adaptive frame/field predictive coding method that has H.264 proposed to carry out an adaptively selected frame coding or a coding again according to the coding cost, and based on the right adaptive frame/field predictive coding method of macro block.

Frame coding effect for frame image is better, does not resemble but fit into field pattern.

Field coding effect for field pattern resembles is better, but does not fit into frame image.

Frame field adaptive predictive coding method is: vision signal is carried out frame coding and field coding at first respectively, and according to both coding costs, the coding result of frame coding or the coding result of a coding are adopted in decision then.This predictive coding method can adapt to frame image and field pattern resembles, and be that unit compares selection but this method is a coding cost with whole frame, so code efficiency is not high.

The frame field adaptive predictive coding method right based on macro block is: carry out earlier based on macro block right frame coding and field coding, according to both coding costs, decision is adopted based on the coding result of the right frame coding of macro block or the coding result of a coding then.This predictive coding method also can adapt to frame image and field pattern resembles, but complexity is very big.

Summary of the invention the objective of the invention is for overcoming the weak point of prior art, proposes in a kind of vision signal the two-stage forecasting coding method based on the sampling macroblock structure.The present invention utilizes the characteristics of sampling macroblock structure, and two stages of adopting are carried out predictive coding.Emphasis has defined forecast coding structure, and this forecast coding structure can effectively improve compression efficiency of video signal in conjunction with other various coding techniquess.

Predict base unit in a kind of video signal coding that the present invention proposes, it is characterized in that said prediction base unit is the macro block that the square of 16 pixels * 16 pixels constitutes, comprise original macro and sampling macro block; Wherein, original macro is the square of continuous 16 pixels * 16 pixels; The sampling macro block is for carrying out the square that level or vertical 1/2 is sampled and rearranged 16 pixels * 16 pixels that obtain to original macro.

Said original macro production method can be: for the original picture of lining by line scan, the square of 16 continuous pixels * 16 pixels just constitutes an original macro; For interleaved original picture, to go up adjacent strange and idol field earlier the time, or idol and strange field pattern resemble by the place position and be combined into frame image, and the square of 16 continuous pixels * 16 pixels just constitutes an original macro in the frame image that is combined into then.

Said sampling macro block can comprise: original macro is not carried out the continuous macro block that any sampling obtains, and this macro block is made up of NS1, NS2, NS3 and four pieces of NS4; Original macro is carried out the horizontal sampling macro block that level 1/2 sampling just obtains, and this macro block is made up of HS1, HS2, HS3 and four pieces of HS4; Original macro is carried out the vertical sampling macro block that vertical 1/2 sampling just obtains, and this macro block is made up of VS1, VS2, VS3 and four pieces of VS4; And original macro carried out the vertical 1/2 vertical-horizontal sampling macro block that level 1/2 sampling obtains of sampling again, this macro block is made up of VHS1, VHS2, VHS3 and four pieces of VHS4.

Based on the two-stage forecasting coding method of sampling macroblock structure, it is characterized in that in a kind of vision signal that the present invention proposes, comprise cataloged procedure and decode procedure;

Said cataloged procedure specifically may further comprise the steps:

1) macro block that the square of 16 pixels * 16 pixels is constituted does not carry out the continuous macro block group NS that any sampling obtains as the prediction base unit to the original macro group; The original macro group is carried out level 1/2 sampling obtain horizontal sampling macro block group HS; The original macro group is carried out vertical 1/2 sampling obtain vertical sampling macro block group VS; And the original macro group is carried out vertical 1/2 level 1/2 sampling of sampling again obtain vertical-horizontal sampling macro block group VHS and form; Carrying out described four kinds of sampling macro blocks in twos, assembly coding constitutes six kinds of macroblock encoding types: NS-HS macroblock encoding type, VS-VHS macroblock encoding type, NS-VS macroblock encoding type, HS-VHS macroblock encoding type, NS-VHS macroblock encoding type and HS-VS macroblock encoding type; By above-mentioned six kinds of type of codings wherein two kinds make up, form three kinds of coding structure: NS-HS and VS-VHS, NS-VS and HS-VHS and NS-VHS and HS-VS coding structure, adopt that any one carries out encoding and decoding in above-mentioned three kinds of coding structures; Determine the coding stage attribute of piece in the current coding macro block according to the sampling macro block characteristics;

2) carry out the phase I coding, comprise the following steps:

(1) from original picture, obtain an original macro,, carry out sample process according to original macro and obtain cataloged procedure the 1st as current coding macro block) four kinds of sampling macro blocks described in the step;

(2) from cataloged procedure the 1st) choose three kinds of coding structures described in the step a kind ofly, the macroblock encoding type of the front in the chosen coding structure is encoded:

At first consider four pieces of first kind of sampling macro block in the macroblock encoding type of the front in the coding structure, coding stage attribute according to these four pieces, if encode in the phase I, then to current block coding and calculating current block coding cost, if at the second stage coding, then estimate current block coding cost; And then four pieces of the sampling of the another kind in the macroblock encoding type of the front in consideration coding structure macro block, coding stage attribute according to these four pieces, if encode in the phase I, then to current block coding and calculating current block coding cost value, if at the second stage coding, then estimate current block coding cost value; At last according to the coding cost value sum of four pieces of these two kinds sampling macro blocks, select the coding result of the little sampling macroblock encoding result of coding cost value as the macroblock encoding type of the front in the coding structure, selected coding cost value is as the coding cost value of the macroblock encoding type of the front in the coding structure;

(3) macroblock encoding type of the back of chosen coding structure is encoded:

At first consider two pieces in upper strata or lower floor of first kind of sampling macro block in the macroblock encoding type of this back, coding stage attribute according to these two pieces, if encode in the phase I, then to current block coding and calculation code cost value, if at the second stage coding, then estimate current block coding cost value; And then two pieces in upper strata or lower floor of the sampling of the another kind in the macroblock encoding type of the back in consideration coding structure macro block, coding stage attribute according to these two pieces, if encode in the phase I, then to current block coding and calculation code cost value, if at the second stage coding, then estimate current block coding cost value; Last cost value sum according to these two kinds sampling macro block upper stratas or two pieces of lower floor, the coding result of two pieces in upper strata or lower floor of the sampling macro block (mb) type that the selection cost value is little is as the coding result of two pieces in macroblock encoding type upper strata or lower floor of the back in the coding structure, and selected cost value is as the coding cost value of two pieces in macroblock encoding type upper strata, back or lower floor;

Carry out the coding of two pieces of lower floor or upper strata in the macroblock encoding type of the back in the coding structure equally, and obtain macroblock encoding type lower floor or the coding result of upper strata piece and the coding cost value of lower floor or upper strata piece of the back in the coding structure;

With the cost value sum of upper and lower layer piece coding cost value as the macroblock encoding type of the back in the coding structure;

(4) encoding code stream of current coding macro block output:

The coding cost value of the macroblock encoding type of the back in the macroblock encoding type of the front in (2) step of comparison cataloged procedure phase I coding in the coding structure and (3) step in the coding structure, the macroblock encoding type of decision current coding macro block: if the coding cost value of the macroblock encoding type of the front in the coding structure is little, the type of coding of current coding macro block is the macroblock encoding type of the front in the coding structure just, again according to the result of this (2) step, the sampling macro block (mb) type of decision current coding macro block, according to the coding stage attribute of piece in the sampling macro block, export the code stream of encoding block; If the coding cost value of the macroblock encoding type of the back in the coding structure is little, the type of coding of current coding macro block is the macroblock encoding type of the back in the coding structure just, again according to the result of phase I coding (3) step, which kind of sampling macro block (mb) type the upper and lower layer piece of decision current coding macro block belongs to, according to the coding stage attribute of piece in the sampling macro block, export the code stream of encoding block;

(5) piece that does not have coding in the current coding macro block is carried out interpolation and obtain reconstructed block, and constituted the reconstruction macro block of current coding macro block with the reconstructed block that obtains by coding;

(6) (1) step to the (5) step of repetition phase I coding, original macro all in original picture are finished coding, and then the phase I encodes and finishes; All reconstruction macro blocks have constituted the reconstruction frames image, the reference frame when encoding as second stage in the phase I coding;

3) carry out the second stage coding, comprise the following steps:

(1) obtain an identical original macro of (1) step of encoding with the phase I from original picture, promptly current coding macro block is carried out sample process according to original macro and is obtained four kinds of macro blocks, be i.e. NS, HS, VS, VHS macro block;

(2) do not have the piece of coding to encode to the phase I in the current coding macro block, the reference frame when resulting reconstruction frames image is encoded as second stage in encoding with the phase I is encoded to the piece of needs coding, and the reconstructed block after obtaining encoding;

The reconstructed block that obtains by interpolation when (3) the alternative phase I of reconstructed block that obtains with coding encodes, and output encoder code stream;

(4) repeat (1) step to the (3) step that second stage is encoded, all original macro are finished the second stage coding in original picture, and then the second stage coding is finished;

Said decode procedure specifically may further comprise the steps:

1) phase I decoding

(1) at first judges the macroblock encoding type that to decode: if the macroblock encoding type of front, then carry out (2) step of phase I decoding, if the macroblock encoding type of back, then carry out (3) step of phase I decoding according to encoding code stream;

(2) when the type of coding of decoded macroblock is the macroblock encoding type of the front in the coding structure, judge the sampling macro block (mb) type of wanting decoded macroblock according to encoding code stream, again according to the coding stage attribute of piece in this sampling macro block, whether decision decodes: if current block is encoded direct decoding and obtain the decoding and rebuilding piece then in the phase I; If current block is encoded in second stage, then current block is stayed the second stage decoding;

(3) when the type of coding of decoded macroblock is the macroblock encoding type of the back in the coding structure, judge according to encoding code stream which kind of sampling macro block two pieces in the upper and lower belong to, while is according to the coding stage attribute of piece in this sampling macro block, whether decision decodes: if current block is encoded direct decoding and obtain the decoding and rebuilding piece then in the phase I; If current block is encoded in second stage, then current block is stayed the second stage decoding;

(4) according to the piece of having decoded the piece that not have decoding in (2) step of phase I decoding or (3) the step macro block is carried out interpolation and obtains reconstructed block, and with (2) step of phase I decoding or (3) step in complete reconstruction macro block of reconstructed block formation of obtaining of decoding;

(5) (1) step to the (4) step of repetition phase I decoding is all decoded up to all macro blocks, and then the phase I decoding is finished; All reconstruction macro blocks have constituted the reconstruction frames image in the phase I decoding, as the reference frame image of second stage decoding;

2) second stage decoding:

(1) not have the piece of decoding to decode to the phase I in the macro block of decoding, the decoding and rebuilding frame image that obtains with the phase I is decoded to these pieces of not decoding, and is obtained the reconstructed block of decoding block as the reference frame of decoding;

(2) the decoding and rebuilding piece with (1) step of second stage decoding substitutes the reconstructed block that the phase I obtains by interpolation, obtains final decoding and rebuilding frame like this, and with this decoding reference frame as the decoding next frame.

Reference frame during said second stage coding also can comprise the reference frame that the phase I uses during block encoding, the reference frame that the reference frame during said second stage decoding uses when also comprising phase I piece decoding.

Said four kinds of sampling macro blocks can comprise: original macro is not carried out the continuous macro block that any sampling obtains, and this macro block is made up of NS1, NS2, NS3 and four pieces of NS4; Original macro is carried out the horizontal sampling macro block that level 1/2 sampling just obtains, and this macro block is made up of HS1, HS2, HS3 and four pieces of HS4; Original macro is carried out the vertical sampling macro block that vertical 1/2 sampling just obtains, and this macro block is made up of VS1, VS2, VS3 and four pieces of VS4; And original macro carried out the vertical 1/2 vertical-horizontal sampling macro block that level 1/2 sampling obtains of sampling again, this macro block is made up of VHS1, VHS2, VHS3 and four pieces of VHS4.

The coding stage attribute of piece can be in the said sampling macro block:

For the NS macro block, each piece is all encoded in the phase I;

For the HS macro block, HS1 and HS3 encoded in the phase I, and HS2 and HS4 encode in second stage;

For the VS macro block, VS1 and VS2 encoded in the phase I, and VS3 and VS4 encode in second stage;

For the VHS macro block, VHS1, VHS3 are placed on the phase I coding, and VHS2 and VHS4 are placed on the second stage coding.

The coding stage attribute of piece can be in the said sampling macro block:

For the HS macro block, HS2 and HS4 can be placed on the phase I coding, HS1 and HS3 encode in second stage; Also HS2 and HS3 can be placed on the phase I coding, HS1 and HS4 are placed on the second stage coding; HS1 and HS4 can also be placed on the phase I coding, HS2 and HS3 are placed on the second stage coding; Any three pieces in HS1, HS2, HS3 and four pieces of HS4 can also be placed on the phase I coding, remaining piece is placed on the second stage coding;

For the VS macro block, VS3 and VS4 can be placed on the phase I coding, VS1 and VS2 are placed on the second stage coding; Any three pieces in VS1, VS2, VS3 and four pieces of VS4 can also be placed on the phase I coding, remaining piece is placed on the second stage coding;

For the VHS macro block, VHS1 and VHS3 can be placed on the phase I coding, VHS2 and VHS4 are placed on the second stage coding; Also VHS2 and VHS4 can be placed on the phase I coding, VHS1 and VHS3 are placed on the second stage coding; Also VHS1 and VHS4 can be placed on the phase I coding, VHS2 and VHS3 are placed on the second stage coding; Also VHS2 and VHS3 can be placed on the phase I coding, VHS1 and VHS4 are placed on the second stage coding; Any one piece in VHS1, VHS2, VHS3 and four pieces of VHS4 can also be placed on the phase I coding, remaining piece is placed on the second stage coding; Any three pieces in VHS1, VHS2, VHS3 and four pieces of VHS4 can also be placed on the phase I coding, remaining piece is placed on the second stage coding.

Principle of the present invention:

When video coding, the height of the quality decision code efficiency of prediction, therefore for an images, if consider that coding is wherein a part of earlier, but this part can be satisfied reconstruction view picture image, with the reference picture of this image reconstruction, can effectively improve the code efficiency of those remainder images so then, Here it is two-stage forecasting cataloged procedure as remainder when coding prediction in this images.In the sampling macroblock structure that the present invention proposes, some part was encoded in the phase I, and some part is stayed the second stage coding, had so just well realized the two-stage forecasting cataloged procedure.

Effect of the present invention:

Main feature of the present invention is to have defined forecast coding structure, and this forecast coding structure can effectively improve compression efficiency of video signal in conjunction with other various coding techniquess.At up-to-date JVT reference software JM61e, under identical experimental condition, the code efficiency that shows this programme of doing experiment is higher than JVT result.

Description of drawings

The macroblock structure schematic diagram that Fig. 1 adopts for the present invention.

Fig. 2 is a sampling macroblock structure schematic diagram of the present invention four types.

Fig. 3 is the interpolation structure schematic diagram of three types of sampling macro blocks of the present invention.

Based on the two-stage forecasting coding method of sampling macroblock structure, reach embodiment in conjunction with the accompanying drawings and be described in detail as follows in a kind of vision signal that embodiment the present invention proposes:

In the present invention, the square of one 16 pixel * 16 pixels is called macro block (Macroblock), and the square of one 8 pixel * 8 pixels is called piece (block), and the square of 16 continuous pixels * 16 pixels is an original macro.

Original macro production method of the present invention is: for the original picture of lining by line scan, the square of 16 continuous pixels * 16 pixels just constitutes an original macro; For interleaved original picture, to go up adjacent strange and idol field earlier the time, or idol and strange field pattern resemble by the place position and be combined into frame image, and the square of 16 continuous pixels * 16 pixels just constitutes an original macro in the frame image that is combined into then, as shown in Figure 1.

Original macro is carried out level or vertical 1/2 sampling, just obtain four types sampling macro block, as shown in Figure 2.

A is continuous macro block (Non-sampling Macroblock-NS) among Fig. 2: original macro is not carried out any sampling just obtain this type of mb, this sampling macro block is made up of NS1, NS2, NS3 and four pieces of NS4, wherein NS1 and NS2 are two pieces in upper strata, and NS3 and NS4 are two pieces of lower floor.Specifically be defined as:

NS1(x，y)＝MB(x，y)，

NS2(x，y)＝MB(x+8，y)，

NS3(x，y)＝MB(x，y+8)，

NS4(x，y)＝MB(x+8，y+8)，x，y＝1，…，8，

Wherein, MB (x, y) be in the original macro (x, pixel value y), x here, y=1 ..., 16.

B is horizontal sampling macro block (Horiztonal-sampling Macroblock-HS) among Fig. 2: original macro is carried out level 1/2 sampling just obtain this type of mb, this sampling macro block is made up of HS1, HS2, HS3 and four pieces of HS4, wherein HS1 and HS2 are two pieces in upper strata, and HS3 and HS4 are two pieces of lower floor.Specifically be defined as:

HS1(x，y)＝MB(2x，y)，

HS2(x，y)＝MB(2x+1，y)，

HS3(x，y)＝MB(2x，y+8)，

HS4(x，y)＝MB(2x+1，y+8)，x，y＝1，…，8，

Wherein, MB (x, y) be in the original macro (x, pixel value y), x here, y=1 ..., 16.

C is vertical sampling macro block (Vertical-sampling Macroblock-VS) among Fig. 2: original macro is carried out vertical 1/2 sampling just obtain this type of mb, this sampling macro block is made up of VS1, VS2, VS3 and four pieces of VS4, wherein VS1 and VS2 are two pieces in upper strata, and VS3 and VS4 are two pieces of lower floor.Specifically be defined as:

VS1(x，y)＝MB(x，2y)，

VS2(x，y)＝MB(x+8，2y)，

VS3(x，y)＝MB(x，2y+1)，

VS4(x，y)＝MB(x+8，2y+1)，x，y＝1，…，8，

Wherein, MB (x, y) be in the original macro (x, pixel value y), x here, y=1 ..., 16.

D is a vertical-horizontal sampling macro block (Vertical-Horiztonal-sampling Macroblock-VHS) among Fig. 2: original macro is carried out vertical 1/2 level 1/2 sampling of sampling again just obtain this type of mb, this sampling macro block is made up of VHS1, VHS2, VHS3 and four pieces of VHS4, wherein VHS1 and VHS2 are two pieces in upper strata, and VHS3 and VHS4 are two pieces of lower floor.Specifically be defined as:

VHS1(x，y)＝MB(2x，2y)，

VHS2(x，y)＝MB(2x+1，2y)，

VHS3(x，y)＝MB(2x，2y+1)，

VHS4(x，y)＝MB(2x+1，2y+1)，x，y＝1，…，8，

Wherein, MB (x, y) be in the original macro (x, pixel value y), x here, y=1 ..., 16.

Above-mentioned four kinds of sampling macro blocks are made up the six kinds of macroblock encoding types of formation of encoding in twos:

1. NS macro block and HS macro block are encoded and be defined as the NS-HS macroblock encoding type;

2. VS macro block and VHS macro block are encoded and be defined as the VS-VHS macroblock encoding type;

3. NS macro block and VS macro block are encoded and be defined as the NS-VS macroblock encoding type;

4. HS macro block and VHS macro block are encoded and be defined as the HS-VHS macroblock encoding type;

5. NS macro block and VHS macro block are encoded and be defined as the NS-VHS macroblock encoding type;

6. HS macro block and VS macro block are encoded and be defined as the HS-VS macroblock encoding type.

Above-mentioned six kinds of macroblock encoding types are formed three kinds of coding structures by the version of first kind of macroblock encoding type and second kind of macroblock encoding type:

The 1st kind of macroblock encoding type (NS-HS macroblock encoding type) and the 2nd kind of macroblock encoding type (VS-VHS macroblock encoding type) combination are constituted the NS-HS-VS-VHS coding structure;

The 3rd kind of macroblock encoding type (NS-VS macroblock encoding type) and the 4th kind of macroblock encoding type (HS-VHS macroblock encoding type) combination are constituted the NS-VS-HS-VHS coding structure;

The 5th kind of type of coding (NS-VHS macroblock encoding type) and the 6th kind of macroblock encoding type (HS-VS macroblock encoding type) combination are constituted the NS-VHS-HS-VS coding structure.

The present invention can adopt that any one carries out encoding and decoding (adopting the NS-HS-VS-VHS coding structure in the present embodiment) in above-mentioned three kinds of coding structures, in above-mentioned three kinds of coding structures, first kind of macroblock encoding type and second kind of macroblock encoding type position in coding structure can exchange, and form other similar coding structure.

The present invention will determine the wherein coding stage attribute of piece (be about to some piece and determine that some piece is encoded in second stage at the phase I coding) according to the sampling macro block characteristics:

Some piece was encoded in the phase I in dissimilar sampling macro blocks, and some piece is encoded in second stage.The principle of distinguishing block encoding stage attribute is: in the sampling macro block, if this piece can be obtained satisfied reconstructed block by other encoding block by interpolation, then this piece is stayed the second stage coding, otherwise encodes in the phase I.

For example: for the NS macro block, each piece must be encoded and could be obtained satisfied reconstructed block, so each piece all must be encoded in the phase I in this macro block.

For the HS macro block, HS2 can obtain its satisfied reconstructed block by the HS1 interpolation; Same HS4 can obtain its satisfied reconstructed block by the HS3 interpolation.Therefore in this type of mb, HS1 and HS3 encoded in the phase I, and HS2 and HS4 encode in second stage.

For the VS macro block, VS3 can obtain its satisfied reconstructed block by the VS1 interpolation, and VS4 can obtain its satisfied reconstructed block by the VS2 interpolation.Therefore in this type of mb, VS1 and VS2 encoded in the phase I, and VS3 and VS4 encode in second stage.

For the VHS macro block, VHS2 can obtain its satisfied reconstructed block by the VHS1 interpolation; Same VHS4 can obtain its satisfied reconstructed block by the VHS3 interpolation.Therefore in this type of mb, VHS1 and VHS3 are placed on the phase I coding, and VHS2 and VHS4 are placed on the second stage coding.

The division of above-mentioned coding stage to piece is an example (being used in the present embodiment), and the present invention can also adopt other zoned format, for example:

For the HS macro block, HS2 and HS4 can be placed on the phase I coding, HS1 and HS3 encode in second stage; Also HS2 and HS3 can be placed on the phase I coding, HS1 and HS4 are placed on the second stage coding; HS1 and HS4 can also be placed on the phase I coding, HS2 and HS3 are placed on the second stage coding; Any three pieces in HS1, HS2, HS3 and four pieces of HS4 can also be placed on the phase I coding, remaining piece is placed on the second stage coding.

For the VS macro block, VS3 and VS4 can be placed on the phase I coding, VS1 and VS2 are placed on the second stage coding; Any three pieces in VS1, VS2, VS3 and four pieces of VS4 can also be placed on the phase I coding, remaining piece is placed on the second stage coding.

For the VHS macro block, VHS1 and VHS3 can be placed on the phase I coding, VHS2 and VHS4 are placed on the second stage coding; Also VHS2 and VHS4 can be placed on the phase I coding, VHS1 and VHS3 are placed on the second stage coding; Also VHS1 and VHS4 can be placed on the phase I coding, VHS2 and VHS3 are placed on the second stage coding; Also VHS2 and VHS3 can be placed on the phase I coding, VHS1 and VHS4 are placed on the second stage coding; Any one piece in VHS1, VHS2, VHS3 and four pieces of VHS4 can also be placed on the phase I coding, remaining piece is placed on the second stage coding; Any three pieces in VHS1, VHS2, VHS3 and four pieces of VHS4 can also be placed on the phase I coding, remaining piece is placed on the second stage coding.

Based on the embodiment of the two-stage forecasting coding method of sampling macroblock structure, comprise cataloged procedure and decode procedure in a kind of vision signal that the present invention proposes;

Said cataloged procedure specifically may further comprise the steps:

The phase I coding

1) obtain an original macro from original picture, promptly current coding macro block is carried out sample process according to original macro and is obtained four types sampling macro block, be i.e. NS, HS, VS, VHS macro block.

2) to NS macro block and HS macro block encode (NS-HS macroblock encoding type):

At first four piece NS1, NS2, NS3 and NS4 of NS macro block are encoded and calculate the cost value of its coding cost as the NS macroblock coding.

Four piece HS1, HS2, HS3 and HS4 to the HS macro block encode then: earlier two piece HS1 in the left side of HS and HS3 are encoded and calculate its coding cost, estimate the coding cost of two piece HS2 in the right and HS4 again, with the cost value sum of four pieces cost value as the HS macroblock coding.

Relatively the cost value of NS macroblock coding and the cost value of HS macroblock coding are selected the result of the little coding result of cost value as the NS-HS macroblock encoding type, and its cost value is as the cost value of NS-HS macroblock encoding type.

3) to VS macro block and VHS macro block encode (VS-VHS macroblock encoding type):

At first two piece VS1 in upper strata of VS macro block and VS2 are encoded and calculate its coding cost, then the left side, the upper strata piece VHS1 of VHS is encoded and calculate its coding cost, the coding cost of upper estimate the right piece VHS2 again, last cost value sum according to two pieces of VS and VHS piece upper strata, the coding result of two pieces in upper strata (VS1 and VS2 or VHS1 and VHS2) of the macro block (mb) type that the selection cost value is little is as the coding result of VS-VHS macroblock encoding type upper strata piece, and its cost value is as the cost value of VS-VHS macroblock encoding type upper strata piece.

Then the left side piece VHS3 of lower floor of VHS is encoded and calculate its coding cost, estimate the right piece VHS4 of lower floor and two the piece VS3 of lower floor of VS and the coding cost of VS4 of VHS again, cost value sum according to two pieces of VS and VHS macro block lower floor, the coding result of two pieces of lower floor (VS3 and VS4 or VHS3 and VHS4) of the macro block (mb) type that the selection cost value is little is as the coding result of VS-VHS macroblock encoding type lower floor piece, and its cost value is as the cost value of VS-VHS macroblock encoding type lower floor piece.

With the cost value sum of upper and lower layer piece cost value as the VS-VHS macroblock encoding type.

In the above-mentioned steps, the priority coded sequence of the upper and lower can be put upside down, and the left and right sides coded sequence of two pieces in the upper and lower can be put upside down.

4) encoding code stream of current coding macro block output:

Comparison step 2) cost value of VS-VHS macroblock encoding type in NS-HS macroblock encoding type and the step 3) in, which kind of type of coding of employing of decision current coding macro block: if the cost value of NS-HS macroblock encoding type is little, the type of coding of current coding macro block is the NS-HS macroblock encoding type just.Again according to the 2nd) result in step, the sampling macro block (mb) type of decision current coding macro block:, then export the encoding code stream of NS1, NS2, NS3 and NS4 piece if the NS-HS macroblock encoding type is a NS sampling macro block; If the NS-HS macroblock encoding type is a HS sampling macro block, then only export the encoding code stream of HS1 and HS3 piece.On the contrary, if the cost value of VS-VHS macroblock encoding type is little, the type of coding of current coding macro block is the VS-VHS macroblock encoding type just.Simultaneously according to the 3rd) result in step, also determined the sampling macro block (mb) type of the upper and lower layer piece of current coding macro block:, then export the encoding code stream of VS1 and VS2 piece if two pieces in the upper strata of VS-VHS macroblock encoding type belong to the VS macro block; If two pieces in the upper strata of VS-VHS macroblock encoding type belong to the VHS macro block, then only export the encoding code stream of VHS1 piece; If two pieces of the lower floor of VS-VHS macroblock encoding type are VHS macro blocks, then only export the encoding code stream of VHS3 piece.

5) piece that does not have coding in the current coding macro block is carried out interpolation and obtains reconstructed block:

Through the 4th) step, the output of may some piece in current coding macro block having encoded, some piece is coding not.Because encoded piece can access the piece of reconstruction, and do not have the piece piece that can not obtain rebuilding of coding, can only obtain the reconstructed block that these do not have encoding block, so just obtained the whole reconstruction macro block of current coding macro block by interpolation.According to the 4th) step, need the piece of interpolation to be: if the type of coding of current coding macro block is the NS-HS macroblock encoding type, and when the NS-HS macroblock encoding type was the HS macro block, then HS2 and HS4 piece needed interpolation.If the type of coding of current coding macro block is the VS-VHS macroblock encoding type, and belong to the VHS macro block when two pieces in its upper strata, then the VHS2 piece needs interpolation; Two pieces belong to the VHS macro block when its lower floor, and then the VHS4 piece needs interpolation; Two pieces belong to the VS macro block when its lower floor, and then two pieces of VS3 and VH4 all need interpolation.The interpolation of piece can adopt various existing interpolation techniques to realize.

6) repeat 1) to 5) step, original macro all in original picture are finished coding, and then the phase I encodes and finishes.All reconstruction macro blocks have constituted the reconstruction frames image, the reference frame when encoding as second stage in the phase I coding.

The second stage coding:

1) from original picture, obtain one with the phase I 1) go on foot identical original macro, promptly current coding macro block is carried out sample process according to original macro and is obtained four types macro block, i.e. NS, HS, VS, VHS macro block.

2) do not have the piece of coding to encode to the phase I in the current coding macro block:

Phase I coding determined the type of coding of current coding macro block and encoded piece and not have the piece of coding, so the piece that need encode of this step is exactly not have the piece of encoding the phase I.Concrete deterministic process is as follows: if the type of coding of current coding macro block is the NS-HS macroblock encoding type, and the NS-HS macroblock encoding type is the HS macro block, and then HS2 and HS4 piece need coding; If the type of coding of current coding macro block is the VS-VHS macroblock encoding type, and two pieces in the upper strata of VS-VHS macroblock encoding type belong to the VHS macro block, and then the VHS2 piece needs coding; If two pieces of the lower floor of VS-VHS macroblock encoding type belong to the VS macro block, then VS3 and VS4 piece need coding, if two pieces of the lower floor of VS-VHS macroblock encoding type belong to the VHS macro block, then the VHS4 piece needs coding.Reference frame when the reference frame that uses during block encoding with resulting reconstruction frames image in the phase I coding and phase I is encoded as second stage together, also can only use the reference frame when resulting reconstruction frames image is encoded as second stage in the phase I coding, piece to the needs coding is encoded, and obtains reconstructed block.

3) output of the code stream of encoding block and renewal reconstructed block:

The code stream of output encoder piece is with the 2nd) the coding and rebuilding piece that obtains of step substitutes the reconstructed block that the phase I obtains by interpolation during coding.

4) repeat 1) to 3) step, all original macro are finished the second stage coding in original picture, and then the second stage coding is finished.

In above-mentioned cataloged procedure, macroblock coding and block encoding can adopt existing various coding techniques to realize.Behind the block encoding, the coding cost of computing block also is to adopt existing coding cost value computing technique.The coding cost of estimation piece is meant does not carry out this block encoding, and just according to encoded piece around it, estimate the coding cost of this piece, for example the coding cost of a piece can be estimated as in piece encoded around it and its coding cost value of the most similar.

Said decode procedure specifically may further comprise the steps:

The phase I decoding

1) judge the macro block (mb) type of decoding:

At first judge the macroblock encoding type that to decode according to encoding code stream.If the NS-HS macroblock encoding type then carried out for the 2nd step, if the VS-VHS macroblock encoding type then carried out for the 3rd step.

2) decoding of NS-HS macroblock encoding type:

Judge the sampling macro block (mb) type of this NS-HS macroblock encoding type according to encoding code stream: if the NS macro block, direct decoding NS1, NS2, NS3 and four pieces of NS4; If the HS macro block, two piece HS1 on the left side and HS3 in this macro block of direct decoding, two the piece HS2 and the HS4 on the right stay the second stage decoding.

3) decoding of VS-VHS macroblock encoding type:

Judge the sampling macro block (mb) type of two pieces in upper strata according to code stream: if two pieces in upper strata belong to the VS type, direct decoding this two piece VS1 and VS2; If two pieces in upper strata belong to the VHS type, the piece VHS1 on the left side in these two pieces of direct decoding, the piece VHS2 on the right stay the second stage decoding.

Then, judge the sampling macro block (mb) type of two pieces of lower floor according to code stream: if two pieces of lower floor belong to the VS macro block, then these two piece VS1 and VS2 stay the second stage decoding; If two pieces of lower floor belong to the VHS macro block, the piece VHS3 on the left side in these two pieces of direct decoding, the piece VHS4 on the right stay the second stage decoding.

4) to the 2nd) step or the 3rd) not have the piece of decoding to carry out interpolation acquisition reconstructed block in the macro block in step:

According to the piece of having decoded the piece that does not have decoding is carried out interpolation, so just obtained a complete reconstruction macro block.Fig. 3 has represented the interpolation situation of 3 types sampling macro block, and wherein a is the HS macro block, and b is the VS macro block, and c is the VHS macro block, and from colour specification decoding block, grey colour specification needs the piece of interpolation in every kind of macro block.Here the interpolation of piece adopt with cataloged procedure in identical interpolation technique during the piece interpolation.

5) repeat the 1st) to the 4th) step, all decoded up to all macro blocks, then the phase I decoding is finished.All reconstruction macro blocks have constituted the reconstruction frames image in the phase I decoding, as the reference picture of second stage decoding.

The second stage decoding:

1) do not have the piece of decoding to decode to the phase I in the macro block of decoding:

Through the phase I decoding, in macro block, may also have the not decoding of some pieces.Reference frame when the decoding reference frame that uses of decoding and rebuilding frame image that obtains with the phase I and phase I is decoded as second stage, also can only use the reference frame when resulting reconstruction frames image is decoded as second stage in the phase I decoding, again these pieces of not decoding are decoded, obtain its reconstructed block.

2) upgrade the decoding and rebuilding frame:

With the 1st) the decoding and rebuilding piece in step substitutes the phase I and obtains reconstructed block by interpolation, obtains final decoding and rebuilding frame like this, and with this decoding reference frame as the decoding next frame.

In above-mentioned decode procedure, piece is decoded and can be adopted and encode corresponding existing various decoding techniques realizations.

Claims (5)

1, in a kind of vision signal based on the sampling macroblock structure the two-stage forecasting coding method, it is characterized in that, comprise cataloged procedure and decode procedure;

Said cataloged procedure specifically may further comprise the steps:

1) macro block that the square of 16 pixel x16 pixels is constituted does not carry out the continuous macro block group NS that any sampling obtains as the prediction base unit to the original macro group; The original macro group is carried out level 1/2 sampling obtain horizontal sampling macro block group HS; The original macro group is carried out vertical 1/2 sampling obtain vertical sampling macro block group VS; And the original macro group is carried out vertical 1/2 level 1/2 sampling of sampling again obtain vertical-horizontal sampling macro block group VHS and form; Carrying out described four kinds of sampling macro blocks in twos, assembly coding constitutes six kinds of macroblock encoding types: NS-HS macroblock encoding type, VS-VHS macroblock encoding type, NS-VS macroblock encoding type, HS-VHS macroblock encoding type, NS-VHS macroblock encoding type and HS-VS macroblock encoding type; By above-mentioned six kinds of type of codings wherein two kinds make up, form three kinds of coding structure: NS-HS and VS-VHS, NS-VS and HS-VHS and NS-VHS and HS-VS coding structure, adopt that any one carries out encoding and decoding in above-mentioned three kinds of coding structures; Determine the coding stage attribute of piece in the current coding macro block according to the sampling macro block characteristics;

2) carry out the phase I coding, comprise the following steps:

(1) from original picture, obtain an original macro,, carry out sample process according to original macro and obtain cataloged procedure the 1st as current coding macro block) four kinds of sampling macro blocks described in the step;

(2) from cataloged procedure the 1st) choose three kinds of coding structures described in the step a kind ofly, the macroblock encoding type of the front in the chosen coding structure is encoded:

At first consider four pieces of first kind of sampling macro block in the macroblock encoding type of the front in the coding structure, coding stage attribute according to these four pieces, if encode in the phase I, then to current block coding and calculating current block coding cost, if at the second stage coding, then estimate current block coding cost value; And then four pieces of the sampling of the another kind in the macroblock encoding type of the front in consideration coding structure macro block, coding stage attribute according to these four pieces, if encode in the phase I, then to current block coding and calculating current block coding cost value, if at the second stage coding, then estimate current block coding cost value; At last according to the coding cost value sum of four pieces of these two kinds sampling macro blocks, select the coding result of the little sampling macroblock encoding result of coding cost value as the macroblock encoding type of the front in the coding structure, selected coding cost value is as the coding cost value of the macroblock encoding type of the front in the coding structure;

(3) macroblock encoding type of the back of chosen coding structure is encoded:

At first consider two pieces in upper strata or lower floor of first kind of sampling macro block in the macroblock encoding type of this back, coding stage attribute according to these two pieces, if encode in the phase I, then to current block coding and calculation code cost value, if at the second stage coding, then estimate current block coding cost value; And then two pieces in upper strata or lower floor of the sampling of the another kind in the macroblock encoding type of the back in consideration coding structure macro block, coding stage attribute according to these two pieces, if encode in the phase I, then to current block coding and calculation code cost value, if at the second stage coding, then estimate current block coding cost value; Last cost value sum according to these two kinds sampling macro block upper stratas or two pieces of lower floor, the coding result of two pieces in upper strata or lower floor of the sampling macro block (mb) type that the selection cost value is little is as the coding result of two pieces in macroblock encoding type upper strata or lower floor of the back in the coding structure, and selected cost value is as the coding cost value of two pieces in macroblock encoding type upper strata, back or lower floor;

Carry out the coding of two pieces of lower floor or upper strata in the macroblock encoding type of the back in the coding structure equally, and obtain macroblock encoding type lower floor or the coding result of upper strata piece and the coding cost value of lower floor or upper strata piece of the back in the coding structure;

With the cost value sum of upper and lower layer piece coding cost value as the macroblock encoding type of the back in the coding structure;

(4) encoding code stream of current coding macro block output:

The coding cost value of the macroblock encoding type of the back in the macroblock encoding type of the front in (2) step of comparison cataloged procedure phase I coding in the coding structure and (3) step in the coding structure, the macroblock encoding type of decision current coding macro block: if the coding cost value of the macroblock encoding type of the front in the coding structure is little, the type of coding of current coding macro block is the macroblock encoding type of the front in the coding structure just, again according to the result of this (2) step, the sampling macro block (mb) type of decision current coding macro block, according to the coding stage attribute of piece in the sampling macro block, export the code stream of encoding block; If the coding cost value of the macroblock encoding type of the back in the coding structure is little, the type of coding of current coding macro block is the macroblock encoding type of the back in the coding structure just, again according to the result of phase I coding (3) step, which kind of sampling macro block (mb) type the upper and lower layer piece of decision current coding macro block belongs to, according to the coding stage attribute of piece in the sampling macro block, export the code stream of encoding block;

(5) piece that does not have coding in the current coding macro block is carried out interpolation and obtain reconstructed block, and constituted the reconstruction macro block of current coding macro block with the reconstructed block that obtains by coding;

(6) (1) step to the (5) step of repetition phase I coding, original macro all in original picture are finished coding, and then the phase I encodes and finishes; All reconstruction macro blocks have constituted the reconstruction frames image, the reference frame when encoding as second stage in the phase I coding;

3) carry out the second stage coding, comprise the following steps:

(1) obtain an identical original macro of (1) step of encoding with the phase I from original picture, promptly current coding macro block is carried out sample process according to original macro and is obtained four kinds of macro blocks, be i.e. NS, HS, VS, VHS macro block;

(2) do not have the piece of coding to encode to the phase I in the current coding macro block, the reference frame when resulting reconstruction frames image is encoded as second stage in encoding with the phase I is encoded to the piece of needs coding, and the reconstructed block after obtaining encoding;

The reconstructed block that obtains by interpolation when (3) the alternative phase I of reconstructed block that obtains with coding encodes, and output encoder code stream;

(4) repeat (1) step to the (3) step that second stage is encoded, all original macro are finished the second stage coding in original picture, and then the second stage coding is finished;

Said decode procedure specifically may further comprise the steps:

1) phase I decoding

(1) at first judges the macroblock encoding type that to decode: if the macroblock encoding type of front, then carry out (2) step of phase I decoding, if the macroblock encoding type of back, then carry out (3) step of phase I decoding according to encoding code stream;

(2) when the type of coding of decoded macroblock is the macroblock encoding type of the front in the coding structure, judge the sampling macro block (mb) type of wanting decoded macroblock according to encoding code stream, again according to the coding stage attribute of piece in this sampling macro block, whether decision decodes: if current block is encoded direct decoding and obtain the decoding and rebuilding piece then in the phase I; If current block is encoded in second stage, then current block is stayed the second stage decoding;

(3) when the type of coding of decoded macroblock is the macroblock encoding type of the back in the coding structure, judge according to encoding code stream which kind of sampling macro block two pieces in the upper and lower belong to, while is according to the coding stage attribute of piece in this sampling macro block, whether decision decodes: if current block is encoded direct decoding and obtain the decoding and rebuilding piece then in the phase I; If current block is encoded in second stage, then current block is stayed the second stage decoding;

(4) according to the piece of having decoded the piece that not have decoding in (2) step of phase I decoding or (3) the step macro block is carried out interpolation and obtains reconstructed block, and with (2) step of phase I decoding or (3) step in complete reconstruction macro block of reconstructed block formation of obtaining of decoding;

(5) (1) step to the (4) step of repetition phase I decoding is all decoded up to all macro blocks, and then the phase I decoding is finished; All reconstruction macro blocks have constituted the reconstruction frames image in the phase I decoding, as the reference frame image of second stage decoding;

2) second stage decoding:

(1) not have the piece of decoding to decode to the phase I in the macro block of decoding, the decoding and rebuilding frame image that obtains with the phase I is decoded to these pieces of not decoding, and is obtained the reconstructed block of decoding block as the reference frame of decoding;

(2) the decoding and rebuilding piece with (1) step of second stage decoding substitutes the reconstructed block that the phase I obtains by interpolation, obtains final decoding and rebuilding frame like this, and with this decoding reference frame as the decoding next frame.

2, in the vision signal as claimed in claim 1 based on the sampling macroblock structure the two-stage forecasting coding method, it is characterized in that, reference frame when said second stage is encoded also comprises the reference frame that uses when the phase I encodes, and the reference frame when said second stage is decoded also comprises the reference frame of use when the phase I decodes.

3, in the vision signal as claimed in claim 1 based on the sampling macroblock structure the two-stage forecasting coding method, it is characterized in that, said four kinds of sampling macro blocks comprise: original macro is not carried out the continuous macro block that any sampling obtains, and macro block is made up of NS1, NS2, NS3 and four pieces of NS4 continuously; Original macro is carried out the horizontal sampling macro block that level 1/2 sampling just obtains, and the horizontal sampling macro block is made up of HS1, HS2, HS3 and four pieces of HS4; Original macro is carried out the vertical sampling macro block that vertical 1/2 sampling just obtains, and the vertical sampling macro block is made up of VS1, VS2, VS3 and four pieces of VS4; And original macro carried out the vertical 1/2 vertical-horizontal sampling macro block that level 1/2 sampling obtains of sampling again, vertical-horizontal sampling macro block is made up of VHS1, VHS2, VHS3 and four pieces of VHS4.

4, in the vision signal as claimed in claim 3 based on the two-stage forecasting coding method of sampling macroblock structure, it is characterized in that the coding stage attribute of piece is in said four kinds of sampling macro blocks:

For the NS macro block, each piece is all encoded in the phase I;

For the HS macro block, HS1 and HS3 encoded in the phase I, and HS2 and HS4 encode in second stage;

For the VS macro block, VS1 and VS2 encoded in the phase I, and VS3 and VS4 encode in second stage;

For the VHS macro block, VHS1, VHS3 are placed on the phase I coding, and VHS2 and VHS4 are placed on the second stage coding.

5, in the vision signal as claimed in claim 4 based on the sampling macroblock structure the two-stage forecasting coding method, it is characterized in that the coding stage attribute of piece is in the said sampling macro block:

For the HS macro block, HS2 and HS4 can be placed on the phase I coding, HS1 and HS3 encode in second stage; Also HS2 and HS3 can be placed on the phase I coding, HS1 and HS4 are placed on the second stage coding; HS1 and HS4 can also be placed on the phase I coding, HS2 and HS3 are placed on the second stage coding; Any three pieces in HS1, HS2, HS3 and four pieces of HS4 can also be placed on the phase I coding, remaining piece is placed on the second stage coding;

For the VS macro block, VS3 and VS4 can be placed on the phase I coding, VS1 and VS2 are placed on the second stage coding; Any three pieces in VS1, VS2, VS3 and four pieces of VS4 can also be placed on the phase I coding, remaining piece is placed on the second stage coding;

For the VHS macro block, VHS1 and VHS3 can be placed on the phase I coding, VHS2 and VHS4 are placed on the second stage coding; Also VHS2 and VHS4 can be placed on the phase I coding, VHS1 and VHS3 are placed on the second stage coding; Also VHS1 and VHS4 can be placed on the phase I coding, VHS2 and VHS3 are placed on the second stage coding; Also VHS2 and VHS3 can be placed on the phase I coding, VHS1 and VHS4 are placed on the second stage coding; Any one piece in VHS1, VHS2, VHS3 and four pieces of VHS4 can also be placed on the phase I coding, remaining piece is placed on the second stage coding; Any three pieces in VHS1, VHS2, VHS3 and four pieces of VHS4 can also be placed on the phase I coding, remaining piece is placed on the second stage coding.