CN101004837B

CN101004837B - Method for adding restarting marker in JPEG compressed data, and multi-chip decoding method

Info

Publication number: CN101004837B
Application number: CN200610173365XA
Authority: CN
Inventors: 居晓波
Original assignee: Vimicro Corp
Current assignee: Vimicro Corp
Priority date: 2006-12-30
Filing date: 2006-12-30
Publication date: 2010-04-14
Anticipated expiration: 2026-12-30
Also published as: CN101004837A

Abstract

A method for adding restart up label in JPEG compressed data enables decoder to make decoding operation properly although quite numbers of RST marks are lost in transmission course by utilizing JPEG standard prereserved code word as RST mark, only part lost RST marks is error pattern and the other parts are normal patterns when pattern is decoded and displayed out. The said method supports multi-chip simultaneous-decoding for raising the decoding efficiency.

Description

The method and the multi-chip decoding method that in the JPEG packed data, add restarting marker

Technical field

The present invention relates to the compression of images field, particularly in the JPEG packed data, add the method and the multi-chip decoding method of restarting marker.

Technical background

JPEG is the english abbreviation of JPEG (joint photographic experts group) (Joint Picture Expert Group), is a kind of compressed encoding standard of still image.

Because in the jpeg image coding, piece image is not once to encode to finish, and encodes separately separately but be divided into several data cells, is called macro block in this data unit will once encoding.Below macro block is done simple introduction, a macro block comprises several minimum macroelements, and minimum macroelement then is made up of several pieces block.Following mask body is introduced the notion of block and minimum macroelement.Comprise 8*8 encoded radio among the block, for example,, comprise 8*8 Y value among the block for yuv data, or 8*8 U value, or 8*8 V value.And minimum macroelement, image with the YUV411 form is an example, 4 Y values of horizontal every mistake just have 1 U and 1 V value, then, a minimum macroelement promptly comprises the pixel value of 8 row, 32 row, comprising the block of 4 Y values, the block of the block of 1 U value and 1 V value, promptly minimum macroelement is necessary for the minimum data unit of the complete b lock that has comprised each dissimilar pixel values.

Because each macro block is encoded separately separately,, a mark RST who restarts to encode can be arranged all so begin at each macro block through coding.The RST value is recycling from FFD1～FFD7.This just means in cataloged procedure, if picture size is too big, the sign RST sign that has a plurality of FFD1～FFD7 appears in the encoding stream.If in transmission course, there is the RST sign of one or more groups FFD1～FFD7 all to lose, then just can not find mistake in decoder end, can decode obtains wrong figure.For example decoding finishes decoding end to macro block n, and macro block n+1 restarts mark RST value FFD3～FFD7 and FFD1～FFD2 has all lost to 7 of macro block n+7 in transmission course, and macro block n+8 normal transmission, so after decoding end is received the FFD3 mark of macro block n+8, just can't learn that what receive has not been the signal of macro block n, so just error code may occur, as shown in Figure 1, all wrong situation of image of back may occur.At this moment, have only to time piece image restart just to recover normal.

Summary of the invention

In view of this, the technical issues that need to address of the present invention are exactly to recycle FFD1～FFD7 in the existing Joint Photographic Experts Group may cause the decoding back problem of wrong figure to occur.

In order to solve the problems of the technologies described above, the invention provides a kind of method that in the JPEG packed data, adds restarting marker, may further comprise the steps:

100 are divided into several macro blocks with piece image;

200 carry out JPEG separately to each macro block encodes;

300 begin place's adding at described macro block through the JPEG coding restarts mark RST, the value of the described RST mark codeword reserved that uses in order, described codeword reserved is FF10～FFBF, totally 208, use in order by FF10 to FFBF, start anew to recycle once more after whenever using one time;

400 judge whether piece image encodes finishes, if do not finish, then execution in step 200, if finish, and then present image end-of-encode.

Further, described macro block comprises several minimum macroelements, comprises the complete b lock of dissimilar pixel values in each minimum macroelement, and a block is the set of the same type pixel value of 8*8.

The present invention also provides a kind of multi-chip decoding method, is used for the described coding result of claim 1 is decoded, and may further comprise the steps:

500 obtain the jpeg image data, are unit with the macro block with it, and each macro block is sent into a decoding chip

In decode decoding when using a plurality of decoding chips to carry out a plurality of macro block simultaneously;

600 synthesize the data of a plurality of decoding chips output in proper order according to the value of RST mark, the value of the described RST mark codeword reserved that uses in order, described codeword reserved is FF10～FFBF, totally 208, use in order by FF10 to FFBF, start anew to recycle once more after whenever using one time.

The present invention utilizes the value of the codeword reserved of Joint Photographic Experts Group as the RST sign, and compared with prior art, operational code word is abundant, and therefore lose under the situation of a plurality of RST signs in transmission course the coding back, and demoder still can normal decoder.The part that the figure that demonstrates after the decoding only loses the RST sign is wrong figure, and the figure of other parts is normal.Simultaneously, the present invention can also support the multicore sheet to decode simultaneously, can improve decoding efficiency greatly.

Description of drawings

Fig. 1 in the prior art based on the synoptic diagram of JPEG wrong figure that coding method causes;

Fig. 2 adds the method flow diagram of restarting marker in the JPEG packed data for the present invention;

Fig. 3 is for after using the present invention, and the RST mark is lost the view data synoptic diagram that does not cause the wrong figure in big zone to produce.

Embodiment

Below in conjunction with accompanying drawing, further describe method of the present invention, may further comprise the steps:

100 are divided into several macro blocks with piece image;

Image with the YUV411 form in the background technology is an example, suppose that it is of a size of 640*480, then it can be divided into 80*60=4800 Yblock, 40*30=1200 Ublock and 40*30=1200 Vblock, so its minimum macroelement is 40*30=1200, comprise 4 of Yblock in each minimum macroelement, and each 1 of Vblock and Ublock.And each coded data unit, promptly macro block can be made up of one or more minimum macroelements.

200 pairs of macro blocks carry out the JPEG coding separately;

After piece image is divided into macro block, macro block is carried out the JPEG coding one by one.

300 begin place's adding at described macro block through the JPEG coding restarts mark RST;

Beginning place's adding at the macro block through coding and restart mark RST, in the present invention, is that sequential loop uses codeword reserved as macro block opening flag value.Described codeword reserved can be FF10～FFBF.For example current macro is a n macro block, and its RST is encoded to FF13.If n+1 macro block arranged, then after the end-of-encode, the RST of its adding is labeled as FF14.Value in using up FF10～FFBF can sequential loop re-use FF10～FFBF as the RST mark.But because FF10～FFBF has 208 code words of as many as, with respect to 7 values of the FFD0～FFD7 in the primary standard, the repetition probability of RST mark is little.Behind lost part RST mark, decoding end still can correctly solve the data of other macro block, as shown in Figure 3 like this, bad figure part only can part occur with " O " expression, bad as seen from the figure figure with " X " expression, good figure part, can be not out of control, thus greatly reduce wrong incidence.

Do not finish if the macro block in the piece image is all encoded, then proceed coding, if coding finishes, then this picture coding finishes.

And use FF10～FFBF, and can also support the multicore slice encode, the different macro blocks in the piece image can be decoded in different decoding chips, then according to the synthetic again piece image of RST mark.Concrete coding/decoding method is:

500 obtain the jpeg image data, are unit with the macro block with it, and each macro block is sent in the decoding chip and decoded, decoding when using a plurality of decoding chips to carry out a plurality of macro block simultaneously;

600 synthesize the data of a plurality of decoding chips output according to the order of RST.

Because code word is abundant, just do not worry the built-up sequence of the data of different decoding chips output, so composograph correctly.Therefore improved decoding efficiency.

The above only is preferred embodiment of the present invention, and is in order to restriction the present invention, within the spirit and principles in the present invention not all, any modification of being done, is equal to replacement etc., all should be included within protection scope of the present invention.

Claims

1. in the JPEG packed data, add the method for restarting marker, it is characterized in that, may further comprise the steps:

100 are divided into several macro blocks with piece image;

200 carry out JPEG separately to each macro block encodes;

300 begin place's adding at described macro block through the JPEG coding restarts mark RST, the value of the described RST mark codeword reserved that uses in order, described codeword reserved is FF10～FFBF, totally 208, use in order by FF10 to FFBF, start anew to recycle once more after whenever using one time.

2. method according to claim 1 is characterized in that, described macro block comprises several minimum macroelements, comprises the complete b lock of dissimilar pixel values in each minimum macroelement, and a block is the set of the same type pixel value of 8*8.

3. the multi-chip decoding method is used for the described coding result of claim 1 is decoded, and it is characterized in that, may further comprise the steps:

600 synthesize the data of a plurality of decoding chips output in proper order according to the value of RST mark, the value of the described RST mark codeword reserved that uses in order, described codeword reserved is FF10～FFBF, totally 208, use in order by FF10 to FFBF, start anew to recycle once more after every use one time.