CN108574841A - A kind of coding method and device based on adaptive quantizing parameter - Google Patents

Abstract

An embodiment of the present invention provides a kind of coding methods based on adaptive quantizing parameter and device, method to include：Obtain the quantization parameter of coding unit to be encoded；According to preset quality threshold, preset coding unit size, quantization parameter, coding unit to be encoded is encoded, acquisition includes the coding result of multiple mass figures；Compare mass figures and quality threshold, when being unsatisfactory for preset first quality judging condition there are a mass figures, reduce quantization parameter, and coding is re-started to coding unit to be encoded, until coding result meets preset first quality judging condition；When all mass figures meet preset first quality judging condition, and when being unsatisfactory for preset second quality judging condition there are a mass figures, increase quantization parameter, and coding is re-started to coding unit to be encoded, until coding result meets the first quality judging condition, the second quality judging condition.

Description

A kind of coding method and device based on adaptive quantizing parameter

Technical field

The present invention relates to field of video encoding, more particularly to a kind of coding method based on adaptive quantizing parameter and dress It sets.

Background technology

With the development of internet and Digital object identifier, Video Applications be deep into people work, life it is each A corner, such as carry out video conference, shooting, viewing, download and transmitting video image.Video Applications have become internet And the maximum hot spot of digital multimedia field.

Main problem is coding and decoding video, especially video coding process in Video Applications, needs to pass through original image Coded treatment, the smaller coded image of boil down to occupied space is to carry out network storage or network transmission, therefore, how to obtain The compression efficiency of higher Video coding becomes the matter of utmost importance of field of video encoding.And in video coding process, QP The determination of (Quantization Parameter, quantization parameter) is a critical issue, and the size of QP directly influences coding Quality and compression efficiency, QP is bigger, and the distortion of coded image and original image is bigger, and the quality of coding is poorer；QP is smaller, coding The encoder bit rate of image is bigger, causes the occupied space of coded image bigger, compression efficiency is lower.

Existing method for video coding considers the referring-to relation of video interframe to determine the QP of each coding unit, and root Video coding is carried out one by one to coding unit according to the QP of each coding unit, obtains the higher coding result of overall compression efficiency. When this method obtains overall compression efficiency higher coding result, cataloged procedure is using being fixed the QP of each coding unit Value, but the distortion that this value mode may result in some coding units is excessive, influences video image binary encoding Quality, to cannot be satisfied demand of the specific application scene to coding quality, the applied field of specific application scene such as HD video Scape etc..

Invention content

The embodiment of the present invention is designed to provide a kind of coding method based on adaptive quantizing parameter and device, can The quantization parameter for adaptively changing coding unit to be encoded reduces the distortion of coding unit to be encoded, disclosure satisfy that specific Demand of the application scenarios to coding quality.Specific technical solution is as follows：

The embodiment of the invention discloses a kind of coding methods based on adaptive quantizing parameter, including：

Obtain the quantization parameter of coding unit to be encoded；

According to preset quality threshold, preset coding unit size, the quantization parameter, to coding unit to be encoded It is encoded, obtains the coding result of coding unit to be encoded, the coding result includes multiple mass figures；

Compare the mass figures and the quality threshold, when there are a mass figures to be unsatisfactory for preset first mass When decision condition, quantization parameter is reduced, and according to the quantization parameter after the quality threshold, the coding unit size, reduction, Coding is re-started to coding unit to be encoded, until coding result meets the preset first quality judging condition；

When all mass figures meet preset first quality judging condition, and there are a mass figures to be unsatisfactory for presetting The second quality judging condition when, increase quantization parameter, and according to the quality threshold, the coding unit size, increase after Quantization parameter, coding is re-started to coding unit to be encoded, until coding result meets the first quality judging item Part, the second quality judging condition.

Optionally, described that coding unit to be encoded is encoded, including：

Using corresponding, the encoded historical frames image of frame image where coding unit to be encoded, obtain to be encoded The reference encoder unit of coding unit；

Coding unit to be encoded is obtained, the difference with the pixel of the reference encoder unit carries out the difference Discrete cosine transform obtains the frequency domain data of difference；

According to the relationship of preset quantization parameter and quantization step, the corresponding quantization step of quantization parameter is obtained, and utilize The quantization step quantifies the frequency domain data of the difference, the data of the coding unit to be encoded after being quantified；

Entropy coding is carried out to the data of the coding unit to be encoded after the quantization, obtains coding result.

Optionally, described when being unsatisfactory for preset first quality judging condition there are a mass figures, reduce quantization Parameter, including：

When being unsatisfactory for preset first quality judging condition there are a mass figures, it is pre- that quantization parameter is reduced first If quantity；

Correspondingly, it is described when all mass figures meet preset first quality judging condition, and there are a mass numbers When value is unsatisfactory for preset second quality judging condition, increase quantization parameter, including：

When all mass figures meet preset first quality judging condition, and there are a mass figures to be unsatisfactory for presetting The second quality judging condition when, by quantization parameter increase the first preset quantity.

Optionally, described that quantization parameter is reduced by the first preset quantity, later, the method further includes：

First counter, which counts, adds one, and the number counted in first counter is more than preset first count value When, it sends and reminds instruction, wherein the prompting instruction carries counts corresponding coding knot for the last time in the first counter Fruit.

Optionally, described that quantization parameter is increased by the first preset quantity, later, the method further includes：

Second counter, which counts, adds one, and the number counted in second counter is more than preset second count value When, it sends and reminds instruction, wherein the prompting instruction carries counts corresponding coding knot for the last time in the second counter Fruit.

Optionally, described up to coding result meets the preset first quality judging condition, described preset second Quality judging condition, later, the method further includes：

Preserve the coding result of the coding unit to be encoded.

Optionally, the preset quality threshold is：

The upper limit threshold of the pixel mean square deviation MSD of the NxN blocks of preset reconstruction image and original image, wherein the N is Preset natural number；

Correspondingly, the mass figures, are：

The divided multiple corresponding MSD of NxN blocks of coding unit to be encoded；

Correspondingly, the first quality judging condition is, MSD is less than the upper limit threshold of MSD, the second quality judging item Part is the upper limit threshold of MSD and the difference of MSD, is less than the first preset difference value.

Optionally, the preset quality threshold is：

The lower threshold of Y-PSNR PSNR；

Correspondingly, the mass figures, are：

The PSNR；

Correspondingly, the first quality judging condition is, PSNR is more than the lower threshold of PSNR, second quality judging Condition is the difference of the lower threshold of PSNR and PSNR, is less than the second preset difference value.

The embodiment of the invention also discloses a kind of code devices based on adaptive quantizing parameter, including：

Acquisition module, the quantization parameter for obtaining coding unit to be encoded；

Coding module, for according to preset quality threshold, preset coding unit size, the quantization parameter, treating The coding unit of coding is encoded, and the coding result of coding unit to be encoded is obtained, and the coding result includes multiple matter Numerical quantity；

First determination module, for the mass figures and the quality threshold, when there are a mass figures not When meeting preset first quality judging condition, quantization parameter is reduced, and according to the quality threshold, the coding unit ruler It is very little, reduce after quantization parameter, coding is re-started to coding unit to be encoded, up to coding result meet it is described preset First quality judging condition；

Second determination module meets preset first quality judging condition for working as all mass figures, and there are one When mass figures are unsatisfactory for preset second quality judging condition, increase quantization parameter, and according to the quality threshold, the volume Quantization parameter after code unit size, increase, coding is re-started to coding unit to be encoded, until coding result meets institute State the first quality judging condition, the second quality judging condition.

Optionally, the coding module, including：

Submodule is predicted, for utilizing corresponding, the encoded historical frames figure of frame image where coding unit to be encoded Picture obtains the reference encoder unit of coding unit to be encoded；

Transformation submodule, for obtaining coding unit to be encoded, the difference with the pixel of the reference encoder unit, The difference is subjected to discrete cosine transform, obtains the frequency domain data of difference；

Quantify submodule, for the relationship according to preset quantization parameter and quantization step, it is corresponding to obtain quantization parameter Quantization step, and the frequency domain data of the difference is quantified using the quantization step, it is to be encoded after being quantified The data of coding unit；

Entropy coding submodule carries out entropy coding for the data to the coding unit to be encoded after the quantization, obtains Coding result.

Optionally, first determination module, is specifically used for：

When being unsatisfactory for preset first quality judging condition there are a mass figures, it is pre- that quantization parameter is reduced first If quantity；

Correspondingly, second determination module, is specifically used for：

When all mass figures meet preset first quality judging condition, and there are a mass figures to be unsatisfactory for presetting The second quality judging condition when, by quantization parameter increase the first preset quantity.

Optionally, first determination module, is additionally operable to：

First counter, which counts, adds one, and the number counted in first counter is more than preset first count value When, it sends and reminds instruction, wherein the prompting instruction carries counts corresponding coding knot for the last time in the first counter Fruit.

Optionally, second determination module, is additionally operable to：

Second counter, which counts, adds one, and the number counted in second counter is more than preset second count value When, it sends and reminds instruction, wherein the prompting instruction carries counts corresponding coding knot for the last time in the second counter Fruit.

Optionally, described device further includes：

Preserving module, for until coding result meets the preset first quality judging condition, described preset the After two quality judging conditions, the coding result of the coding unit to be encoded is preserved.

Optionally, the preset quality threshold is：

The upper limit threshold of the pixel mean square deviation MSD of the NxN blocks of preset reconstruction image and original image, wherein the N is Preset natural number；

Correspondingly, the mass figures, are：

The divided multiple corresponding MSD of NxN blocks of coding unit to be encoded；

Correspondingly, the first quality judging condition is, MSD is less than the upper limit threshold of MSD, the second quality judging item Part is the upper limit threshold of MSD and the difference of MSD, is less than the first preset difference value.

Optionally, the preset quality threshold is：

The lower threshold of Y-PSNR PSNR；

Correspondingly, the mass figures, are：

The PSNR；

Correspondingly, the first quality judging condition is, PSNR is more than the lower threshold of PSNR, second quality judging Condition is the difference of the lower threshold of PSNR and PSNR, is less than the second preset difference value.

Coding method and device provided in an embodiment of the present invention based on adaptive quantizing parameter, are added in an encoding process Preset quality threshold, after the coding result for obtaining coding unit to be encoded, multiple mass numbers in the coding result Value and preset quality threshold reduce quantization when being unsatisfactory for preset first quality judging condition there are a mass figures Parameter, and according to the quantization parameter after the quality threshold, the coding unit size, reduction, to coding unit to be encoded Coding is re-started, until coding result meets the preset first quality judging condition.When all mass figures meet in advance If the first quality judging condition, and when being unsatisfactory for preset second quality judging condition there are a mass figures, incrementss Change parameter, and according to the quantization parameter after the quality threshold, the coding unit size, increase, to coding list to be encoded Member re-starts coding, until coding result meets the first quality judging condition, the second quality judging condition.

In cataloged procedure compared with the prior art, the quantization parameter of coding unit to be encoded is fixed value, the present invention Embodiment can adaptively be changed to be encoded according to quality threshold, the first quality judging condition and the second quality judging condition The quantization parameter of coding unit reduces the distortion of unit to be encoded, obtains the first quality judging condition and the second quality judging item Under part limitation, ensure coding quality and the higher coding result of compression efficiency, using the embodiment of the present invention to each to be encoded Coding unit encoded, the coding unit to be encoded for occurring being distorted is recompiled in time, can be avoided to complete After the completion of portion's coding unit coding to be encoded, due to being distorted the case where larger whole recompiles.Therefore, the present invention is implemented Example can effectively improve the compression efficiency of coding under the premise of meeting specific application scene, disclosure satisfy that specific application scene pair The demand of coding quality.

Certainly, it implements any of the products of the present invention or method must be not necessarily required to reach all the above excellent simultaneously Point.

Description of the drawings

In order to more clearly explain the embodiment of the invention or the technical proposal in the existing technology, to embodiment or will show below There is attached drawing needed in technology description to be briefly described, it should be apparent that, the accompanying drawings in the following description is only this Some embodiments of invention for those of ordinary skill in the art without creative efforts, can be with Obtain other attached drawings according to these attached drawings.

Fig. 1 is a kind of flow chart of the coding method based on adaptive quantizing parameter of the embodiment of the present invention；

Fig. 2 is another flow chart of the coding method based on adaptive quantizing parameter of the embodiment of the present invention；

Fig. 3 is the flow chart of the example based on method shown in Fig. 2；

Fig. 4 is the flow chart of another example based on method shown in Fig. 2；

Fig. 5 is a kind of structure chart of the code device based on adaptive quantizing parameter of the embodiment of the present invention；

Fig. 6 is another structure chart of the code device based on adaptive quantizing parameter of the embodiment of the present invention.

Specific implementation mode

Following will be combined with the drawings in the embodiments of the present invention, and technical solution in the embodiment of the present invention carries out clear, complete Site preparation describes, it is clear that described embodiments are only a part of the embodiments of the present invention, instead of all the embodiments.It is based on Embodiment in the present invention, it is obtained by those of ordinary skill in the art without making creative efforts every other Embodiment shall fall within the protection scope of the present invention.

The embodiment of the invention discloses a kind of coding method based on adaptive quantizing parameter and devices, can adaptively more The quantization parameter for changing coding unit to be encoded reduces the distortion of coding unit to be encoded, disclosure satisfy that specific application scene Demand to coding quality.

A kind of coding method based on adaptive quantizing parameter provided in an embodiment of the present invention is introduced first below.

The data volume of uncompressed video image is huge, causes storage difficult, as a DVD can only store several seconds Uncompressed video image；Or causing transmission difficult, such as 1,000,000 one second digital TV video frequency of bandwidth for transmission needs about 4 minutes Deng.Therefore it needs to compress video image to reduce memory space and improve transmission rate.And because being deposited in video image In redundancy, as having between image adjacent pixel between the adjacent image of the spatial redundancy of stronger correlation, video sequence The similar time redundancy of content, the different coding redundancy of probability that different pixel values occur, people vision system to certain details Insensitive visual redundancy etc. so that video image can be compressed.An important indicator for evaluating compression effectiveness is compression Efficiency, compression efficiency is higher, and expression compression effectiveness is better.Video image is encoded, the video image after being encoded regards Frequency cataloged procedure, that is, to process that video image is compressed.But it is likely to occur video in Video coding compression process The loss of image, loss are presented as the distortion of video image, and distortion is bigger, encodes compressed video image and original video image Difference it is bigger, in fact it could happen that pixel missing, clarity be deteriorated etc., lead to the of poor quality of Video coding.

One frame of video image to be compressed is divided into multiple coding units by existing method for video coding, and each coding is single Member is to include the blocks of multiple pixels, and cataloged procedure is encoded one by one to each coding unit, obtain overall compression efficiency compared with High coding result, existing cataloged procedure may result in code segment unit to meet the requirement of overall compression performance QP values it is improper, and then cause the distortion of some coding units excessive, to influence the quality of video image binary encoding, because This cannot be satisfied demand of the specific application scene to coding quality, such as the application scenarios demand of limitation coding loss.

The quality threshold of limitation coding quality is added in coding unit cataloged procedure to be encoded in the embodiment of the present invention, After the completion of coding, compare quality threshold and the mass figures in coding result, the first quality judging condition is unsatisfactory for existing In the case of, or meet the first quality judging condition but exist be unsatisfactory for the second quality judging condition in the case of, to quantization Parameter carries out corresponding adjustment, and re-starts coding using the quantization parameter after adjustment, until coding result meets the first matter Measure decision condition and the second quality judging condition.The fixation value of the quantization parameter of coding unit compared to the prior art, this Inventive embodiments can adaptively adjust quantization parameter according to coding result, and carry out according to the limitation of quality judging condition It recompiles, therefore the distortion of unit to be encoded can be reduced, obtain the first quality judging condition and the second quality judging condition Under limitation, ensure coding quality and the higher coding result of compression efficiency.

Referring to Fig. 1, Fig. 1 is a kind of flow chart of the coding method based on adaptive quantizing parameter of the embodiment of the present invention, Include the following steps：

Step 101, the quantization parameter of coding unit to be encoded is obtained.

The embodiment of the present invention is executed by processor.Processor can be encoder, the computer with encoding function, or set Set software etc. in a computer.

Coding unit is the base unit of Video coding, can be the block of pixels of different sizes.Such as 32 × 32 picture Plain block etc..

Quantization parameter is that the parameter of quantization encoding, is expressed as QP in Video coding.

In Video coding, quantization encoding is a committed step, and the parameter of quantization encoding actual use is QStep (Quantization Step, quantization step), quantization parameter QP is mainly used for, and the correspondence according to QP and QStep is QStep provides index, and QP can be considered as the serial number of QStep, and each QP corresponds to a QStep.Such as solution is H.264 compiled in coding standard In code device, for luminance coding, QP values 0~51 are corresponding, and Qstep shares 52 values.Different coding standards has respectively Self-corresponding QP and Qstep relationships.

It when QP is minimized 0, indicates that quantization is most fine, on the contrary, when QP is maximized 51, indicates that quantization is most coarse.QP Influence of the size of value to the quality and compression efficiency of Video coding is embodied in, and QP is bigger, the mistake of coded image and original image Very bigger, the quality of Video coding is poorer；QP is smaller, and the encoder bit rate of coded image is bigger, causes the occupancy of coded image empty Between it is bigger, compression efficiency is lower.Therefore, it in actual video cataloged procedure, needs to obtain under coding quality and compression efficiency balance Suitable QP then obtains the corresponding QStep of QP to complete quantization cataloged procedure.

Step 102, according to preset quality threshold, preset coding unit size, quantization parameter, to coding to be encoded Unit is encoded, and the coding result of coding unit to be encoded is obtained, and coding result includes multiple mass figures.

The process of Video coding is actually the process compressed to original image.The compression of video image can be divided To be compressed with the lossless video of the image indifference after decompression before compression, being discrepant with the image after decompression before compression Video compress is damaged, damaging video compress keeps encoding and decoding image different, needs a kind of means come before and after evaluating coding, or decoding The quality of front and back image.Quality evaluation has evaluating objective quality, subjective quality assessment etc..The method of common evaluating objective quality Have SAD (Sum of Absolute Difference, absolute error and), SSD (Sum of Squared Difference, it is poor The quadratic sum of value), MAD (Mean Absolute, average absolute value difference), MSD (Mean Squared Difference, rebuild The pixel mean square deviation of the NxN blocks of image and original image), SNR (Signal Noise Rate, signal-to-noise ratio), PSNR (Peak Signal to noise ratio, Y-PSNR) etc..The method of quality evaluation can be with the model form body of quality evaluation It is existing, such as MSD models, PSNR models.

In the embodiment of the present invention, quality threshold is preset, weighs the threshold value of video encoding quality, can be various video Threshold value in coding quality evaluation method includes the lower threshold MINPSNR of upper limit threshold MAXMSD, PSNR etc. of MSD.

Coding unit size is the size of coding unit, can be sizes, such as 4 × 4,8 × 8,16 × 16,32 × 32 Deng.It should be noted that the selection of coding unit size can influence coding result, if coding unit size is smaller, allow to encode The difference of image and original image is smaller, and the precision of coding is higher, but time complexity can be caused excessively high.Therefore in actual coding In the process, it needs to select suitable coding unit size according to the scene demand of Video coding.

Coding unit to be encoded is encoded, existing various video coding method, such as coding standard may be used H264/AVC, coding standard HEVC etc..Specific cataloged procedure is the prior art, and this will not be repeated here.

Coding result includes the image and multiple mass figures after encoding, wherein mass figures are corresponding with quality threshold 's.

Step 103, compare mass figures and quality threshold, when there are a mass figures to be unsatisfactory for preset first mass When decision condition, quantization parameter is reduced, and according to the quantization parameter after quality threshold, coding unit size, reduction, to be encoded Coding unit re-start coding, until coding result meets preset first quality judging condition.

First quality judging condition is the decision condition of the relationship of preset mass figures and quality threshold.Including quality Numerical value is less than quality threshold or mass figures are more than quality threshold etc..

The embodiment of the present invention is different from the prior art, and the quantization parameter of coding unit to be encoded immobilizes, but By comparing the mass figures in quality threshold and coding result, if in the presence of the first quality judging condition, decrement is unsatisfactory for Change parameter, and uses the quantization parameter after reducing and quality threshold, coding unit size again to coding unit weight to be encoded Newly encoded.The coding quality of Video coding can be improved by reducing quantization parameter.

Step 104, when all mass figures meet preset first quality judging condition, and there are a mass figures not When meeting preset second quality judging condition, increase quantization parameter, and according to quality threshold, coding unit size, increase after Quantization parameter, coding is re-started to coding unit to be encoded, until coding result meets the first quality judging condition, the Two quality judging conditions.

Second quality judging condition is the decision condition of the relationship of preset mass figures and quality threshold.Including quality Numerical value is more than the degree etc. of quality threshold less than the degree or mass figures of quality threshold.

The first quality judging condition is not used only in the embodiment of the present invention, also under the conditions of meeting the first quality judging, continues Compare quality threshold and the mass figures in coding result, if meet the second quality judging condition, if in the presence of being unsatisfactory for second The case where quality judging condition, then increase quantization parameter, with realize ensure coding result meet quality threshold restriction basis On, by increasing QP, the appropriate encoder bit rate for reducing current coded unit improves the purpose of compression efficiency.And after using increase Quantization parameter and quality threshold, coding unit size, coding is re-started to coding unit to be encoded again.The present invention is real Two quality judging conditions of example are applied, adaptive adjusting quantization parameter can reduce the distortion of coding unit to be encoded Meanwhile improving the compression efficiency of coding.

Coding method provided in an embodiment of the present invention based on adaptive quantizing parameter, is added preset in an encoding process Quality threshold, after the coding result for obtaining coding unit to be encoded, compare in coding result multiple mass figures with it is preset Quality threshold, when being unsatisfactory for preset first quality judging condition there are a mass figures, reduction quantization parameter, and according to Quantization parameter after quality threshold, coding unit size, reduction re-starts coding to coding unit to be encoded, until compiling Code result meets preset first quality judging condition.When all mass figures meet preset first quality judging condition, and When being unsatisfactory for preset second quality judging condition there are a mass figures, increase quantization parameter, and according to quality threshold, volume Code unit size, the quantization parameter after increase, coding is re-started to coding unit to be encoded, until coding result satisfaction the One quality judging condition, the second quality judging condition.

In cataloged procedure compared with the prior art, the quantization parameter of coding unit to be encoded is fixed value, the present invention Embodiment can adaptively be changed to be encoded according to quality threshold, the first quality judging condition and the second quality judging condition The quantization parameter of coding unit reduces the distortion of unit to be encoded, obtains the first quality judging condition and the second quality judging item Under part limitation, ensure coding quality and the higher coding result of compression efficiency, using the embodiment of the present invention to each to be encoded Coding unit encoded, the coding unit to be encoded for being unsatisfactory for quality judging condition to there is distortion in time carries out again Coding can avoid after the completion of being encoded to coding unit all to be encoded, due to being distorted the larger feelings all recompiled Condition.Therefore, the embodiment of the present invention can improve code efficiency and the compression ratio of coding, disclosure satisfy that specific application scene to coding The demand of quality.

On the basis of Fig. 1, as preferred embodiment, referring to Fig. 2, Fig. 2 is the embodiment of the present invention based on adaptive quantity Another flow chart for changing the coding method of parameter, includes the following steps：

Step 201, the quantization parameter of coding unit to be encoded is obtained.

In the embodiment of the present invention, quantization parameter can be default value, or pass through other quantization parameter determination methods Obtained numerical value, such as every frame are that each frame determines using the setting method for fixing QP, or according to preset bit rate control method The methods of initial Q P, and then determine each unit QP to be encoded.Therefore the embodiment of the present invention can be used alone, can also be with it His quantization parameter determines that method is connected, and carries out encoding video pictures.

Step 202, according to preset quality threshold, preset coding unit size, quantization parameter, to coding to be encoded Unit is encoded, and the coding result of coding unit to be encoded is obtained, and coding result includes multiple mass figures.

Quality threshold in the embodiment of the present invention is introduced in a manner of the subjective model of quality, wherein subjective model It needs to be reasonably selected according to the application scenarios and use demand of video image.

Traditional coding method is commonly referred to as hybrid coding method, mainly includes the following steps that：

The first step, predictive coding utilize corresponding, the encoded historical frames figure of frame image where coding unit to be encoded Picture obtains the reference encoder unit of coding unit to be encoded.

By existing video image knowledge it is found that video image is divided into multiframe, a frame video image can be divided into more A coding unit carries out Video coding, and such as current video image to be encoded is the 5th frame, then can utilize the encoded of preceding 4 frame The video image of completion obtains the reference picture of the video image of the 5th frame, includes in the reference picture of the video image of the 5th frame Multiple reference encoder units, wherein the corresponding reference encoder unit of coding unit to be encoded in the 5th frame may be preceding 4 frame Coding unit in video image any frame.

Second step, transition coding obtain coding unit to be encoded, the difference with the pixel of reference encoder unit, will Difference carries out discrete cosine transform, obtains the frequency domain data of difference.

Coding unit to be encoded is commonly referred to as residual error, transition coding with the difference of the pixel of reference encoder unit Residual error is converted to remove frequency domain correlation, image is converted into frequency-region signal by transition coding from time-domain signal, and will Tremendously low frequency region in quantity set.

Third walks, quantization encoding, and according to the relationship of preset quantization parameter and quantization step, it is corresponding to obtain quantization parameter Quantization step, and the frequency domain data of difference is quantified using quantization step, the coding unit to be encoded after being quantified Data.

Quantization is reduction image code length under the premise of not reducing visual effect, is reduced unnecessary in recovery of vision Information, quantization encoding quantify the data after transformation, can reduce the dynamic range of image coding, by with more coarse Data indicate fine data to reduce the data volume of coding, can remove the visual redundancy in video sequence to a certain extent.Amount Change is generally divided into scalar quantization and vector quantization, and common coding criterion carries out scalar as H.265 using a kind of scale quantizer Quantization, the quantization to converting residual error coefficient have used the quantizer of 52 grades of step-lengths, quantization step to be incremented by with 12.5%, have used quantization Parameter is indexed quantization step, and quantization parameter often increases by 6, and quantization step is increased by one times, and corresponding coding quality also can There is certain decline.

4th step, entropy coding carry out entropy coding to the data of the coding unit to be encoded after quantization, obtain coding knot Fruit.Entropy coding is encoded to the data after quantization, to remove coding redundancy.Wherein, coding result includes the figure after coding Picture, multiple mass figures corresponding with quality threshold.

Step 203, compare mass figures and quality threshold, when there are a mass figures to be unsatisfactory for preset first mass When decision condition, quantization parameter is reduced by the first preset quantity, and according to the amount after quality threshold, coding unit size, reduction Change parameter, coding is re-started to coding unit to be encoded, until coding result meets preset first quality judging condition.

After obtaining coding result, the embodiment of the present invention is according to the relationship of coding result and subjective model, to quantization parameter It is adjusted, specifically, when being unsatisfactory for preset first quality judging condition there are a mass figures, quantization parameter is subtracted Few first preset quantity.And recompiled according to the QP after adjustment, until coding result meets preset first quality judging item Part.Wherein, the first preset quantity is the numerical value according to industrial requirement or being manually arranged, such as 1,2.

The embodiment of the present invention considers the limitation of subjective model in an encoding process, encoding target occurs after avoiding end-of-encode The case where being unsatisfactory for subjective model.But in view of in one and same coding frame, QP has big difference and can lead to boundary effect.Therefore this hair According to practical application scene, the number recompiled to coding unit to be encoded limits bright embodiment.Namely in step After rapid 203, the embodiment of the invention also includes the first counter, which counts, adds one, and the number counted in the first counter is more than It when preset first count value, sends and reminds instruction, wherein remind instruction to carry and counted for the last time in the first counter Corresponding coding result.Wherein the first count value is the preset limits value for recompiling number, such as 3.The present invention is implemented The first different count values can be arranged according to actual scene demand in example.

The method of the embodiment of the present invention further includes decision being carried out to reminding to instruct, specifically, receiving in the first counter most Once count corresponding coding result afterwards, or stop this coding etc..

Step 204, when all mass figures meet preset first quality judging condition, and there are a mass figures not When meeting preset second quality judging condition, quantization parameter is increased by the first preset quantity, and single according to quality threshold, coding Quantization parameter after elemental size, increase re-starts coding to coding unit to be encoded, until coding result meets the first matter Measure decision condition, the second quality judging condition.

Ibid, the embodiment of the present invention is according to practical application scene, the coding recompiled to coding unit to be encoded Number is limited.Namely after step 204, the embodiment of the invention also includes the second counter, which counts, adds one, and second It when the number that counter counts is more than preset second count value, sends and reminds instruction, wherein instruction is reminded to carry second Corresponding coding result is counted in counter for the last time.Wherein the second count value is the preset limit for recompiling number Value processed, such as 2.The second different count values can be arranged according to actual scene demand in the embodiment of the present invention.

The method of the embodiment of the present invention further includes decision being carried out to reminding to instruct, specifically, receiving in the second counter most Once count corresponding coding result afterwards, or stop this coding etc..

Step 205, the coding result of coding unit to be encoded is preserved.

After coding result meets the first quality judging condition, the second quality judging condition, coding list to be encoded is preserved The coding result of member.Later, the embodiment of the present invention continues the cataloged procedure of next coding unit to be encoded, repeat with Upper step 201 is to step 205, until completing the coding of all coding units to be encoded of video image to be encoded, obtains Complete coded sequence, that is, obtain the video image after complete coding.

Coding method provided in an embodiment of the present invention based on adaptive quantizing parameter utilizes subjectivity in an encoding process Preset quality threshold is added in model, after the coding result for obtaining coding unit to be encoded, compares multiple matter in coding result Numerical quantity will be measured with preset quality threshold when being unsatisfactory for preset first quality judging condition there are a mass figures Change parameter and reduce by the first preset quantity, and according to the quantization parameter after quality threshold, coding unit size, reduction, to be encoded Coding unit re-start coding, until coding result meets preset first quality judging condition.When all mass figures When meeting preset first quality judging condition, and preset second quality judging condition be unsatisfactory for there are a mass figures, Quantization parameter is increased by the first preset quantity, and according to the quantization parameter after quality threshold, coding unit size, increase, is treated The coding unit of coding re-starts coding, until coding result meets the first quality judging condition, the second quality judging condition.

In cataloged procedure compared with the prior art, the quantization parameter of coding unit to be encoded is fixed value, the present invention Embodiment can adaptively be changed to be encoded according to subjective model, the first quality judging condition and the second quality judging condition The quantization parameter of coding unit reduces the distortion of unit to be encoded, obtains the first quality judging condition and the second quality judging item Under part limitation, ensure coding quality and the higher coding result of compression efficiency, using the embodiment of the present invention to each to be encoded Coding unit encoded, the coding unit to be encoded for being unsatisfactory for quality judging condition to there is distortion in time carries out again Coding can avoid after the completion of being encoded to coding unit all to be encoded, due to being distorted the larger feelings all recompiled Condition.The embodiment of the present invention makes the coding of entire coded sequence by the limitation in an encoding process to coding unit coding loss Loss is kept in a certain range, and then the compression efficiency of coding can be improved under the conditions of meeting subjective model.Therefore, originally Inventive embodiments can improve code efficiency and the compression efficiency of coding, disclosure satisfy that need of the specific application scene to coding quality It asks.

It is the flow chart of the example based on method shown in Fig. 2 referring to Fig. 3, Fig. 3, including：

Step 301, the QP of coding unit to be encoded is obtained.

Step 302, according to preset MAXMSD, preset coding unit size and QP, to coding unit to be encoded into Row coding, obtains the coding result of coding unit to be encoded, coding result includes multiple MSD.

In the embodiment of the present invention, the subjective model used is MSD model, specifically, it is single that subjective model, which selects N × N blocks, The MSD values of member are weighing criteria, wherein N=4, and set the permitted maximum MSD of coding result MSD as 8, that is, as matter Measure the upper limit threshold MAXMSD=8 of the MSD of threshold value.Coding unit is sized to 32x32.It should be noted that N is to preset certainly So number, can be arranged as required to different natural numbers, such as 8,16.

HEVC encoders etc. may be used in the embodiment of the present invention, and cataloged procedure repeats no more.

Step 303, the MSD and MAXMSD of more all N × N blocks, if meeting preset first quality judging condition is MSD is less than the upper limit threshold of MSD, that is, MSD<MAXMSD.

Coding unit to be encoded contains multiple N × N blocks, and all N × N blocks are each in statistical coding result of the embodiment of the present invention Self-corresponding MSD, with MAXMSD, if it is MSD to meet preset first quality judging condition<MAXMSD.

If be unsatisfactory for preset first quality judging condition there are a MSD, 304, QP-1 are thened follow the steps, and return Step 302 is executed, according to the QP after MAXMSD, coding unit size and reduction, volume is re-started to coding unit to be encoded Code, until coding result meets preset first quality judging condition.

If all MSD meet preset first quality judging condition, 305 are thened follow the steps, judges whether to meet the second matter It is the upper limit threshold of MSD and the difference of MSD to measure decision condition, is less than the first preset difference value, that is, MAXMSD-MSD≤3.Its In the first preset difference value value be 3.It should be noted that the first preset difference value can be arranged as required to the number that other are more than 0 Value.

If be unsatisfactory for preset second quality judging condition there are a MSD, 306, QP+1 are thened follow the steps, and return Step 302 is executed, according to the QP after MAXMSD, coding unit size and increase, volume is re-started to coding unit to be encoded Code, until coding result meets the first quality judging condition, the second quality judging condition.

It should be noted that in the embodiment of the present invention, QP increases or the number of reduction nevertheless suffers from limitation, what QP was reduced Number is no more than the first count value, and the increased numbers of QP are no more than the second count value.In the embodiment of the present invention, first counts The preferred value of numerical value is 3, and the preferred value of the second count value is 2.

If all MSD meet preset first quality judging condition, the second quality judging condition, 307 are thened follow the steps, is protected Deposit the coding result of coding unit to be encoded.

Subjective mould is added in coding method provided in an embodiment of the present invention based on adaptive quantizing parameter in an encoding process Type MSD after the coding result for obtaining coding unit to be encoded, compares multiple MSD and MAXMSD in coding result, when there are one It is MSD that a MSD, which is unsatisfactory for preset first quality judging condition,<When MAXMSD, by QP-1, and according to MAXMSD, coding unit QP after size, reduction re-starts coding to coding unit to be encoded, until coding result meets preset first mass Decision condition.When all MSD meet preset first quality judging condition, and there are a MSD to be unsatisfactory for preset second matter When amount decision condition is MAXMSD-MSD≤3, by QP+1, and according to the QP after MAXMSD, coding unit size, increase, treat The coding unit of coding re-starts coding, until coding result meets the first quality judging condition, the second quality judging condition.

In cataloged procedure compared with the prior art, the quantization parameter of coding unit to be encoded is fixed value, the present invention Embodiment can adaptively be changed to be encoded according to subjective model MSD, the first quality judging condition and the second quality judging condition Coding unit quantization parameter, reduce the distortion of unit to be encoded, obtain the first quality judging condition and the second quality judging Under condition limitation, ensures coding quality and the higher coding result of compression efficiency, wait compiling to each using the embodiment of the present invention The coding unit of code is encoded, and the coding unit to be encoded for being unsatisfactory for quality judging condition to there is distortion in time carries out weight It is newly encoded, it can avoid to after the completion of coding unit coding all to be encoded, all being recompiled since distortion is larger Situation.The embodiment of the present invention makes the volume of entire coded sequence by the limitation in an encoding process to coding unit coding loss Code loss is kept in a certain range, and then the compression efficiency of coding can be improved under the conditions of meeting subjective model MSD.Cause This, the embodiment of the present invention can improve code efficiency and the compression efficiency of coding, disclosure satisfy that specific application scene to encoding matter The demand of amount.

Referring to Fig. 4, Fig. 4 is the flow chart of another example based on method shown in Fig. 2, including：

Step 401, the QP of coding unit to be encoded is obtained.

Step 402, according to preset MINPSNR, preset coding unit size and QP, to coding unit to be encoded into Row coding, obtains the coding result of coding unit to be encoded, and coding result includes a PSNR.

In the embodiment of the present invention, the subjective model used sets the permitted minimums of coding result PSNR for PSNR models PSNR is 39, that is, the PSNR as quality threshold lower threshold MINPSNR=39.Coding unit is sized to 32x32。

HEVC encoders etc. may be used in the embodiment of the present invention, and cataloged procedure repeats no more.

Step 303, compare PSNR and MINPSNR, if meet preset first quality judging condition and be more than for PSNR The lower threshold of PSNR, that is, PSNR>MINPSNR.

If be unsatisfactory for preset first quality judging condition there are PSNR, 404, QP-1 are thened follow the steps, and return and hold Row step 402 re-starts volume according to the QP after MINPSNR, coding unit size and reduction to coding unit to be encoded Code, until coding result meets preset first quality judging condition.

If PSNR meets preset first quality judging condition, 405 are thened follow the steps, judges whether that meeting the second mass sentences Fixed condition is the difference of the lower threshold of PSNR and PSNR, is less than the second preset difference value, that is, PSNR-MINPSNR≤2.Its In the second preset difference value value be 2.It should be noted that the second preset difference value can be arranged as required to the number that other are more than 0 Value.

If be unsatisfactory for preset second quality judging condition there are PSNR, 406, QP+1 are thened follow the steps, and return and hold Row step 402 re-starts volume according to the QP after MINPSNR, coding unit size and increase to coding unit to be encoded Code, until coding result meets the first quality judging condition, the second quality judging condition.

It should be noted that in the embodiment of the present invention, QP increases or the number of reduction nevertheless suffers from limitation, what QP was reduced Number is no more than the first count value, and the increased numbers of QP are no more than the second count value.In the embodiment of the present invention, first counts The preferred value of numerical value is 3, and the preferred value of the second count value is 2.

If PSNR meets preset first quality judging condition, the second quality judging condition, 407 are thened follow the steps, is preserved The coding result of coding unit to be encoded.

Subjective mould is added in coding method provided in an embodiment of the present invention based on adaptive quantizing parameter in an encoding process Type PSNR after the coding result for obtaining coding unit to be encoded, compares PSNR and MINPSNR in coding result, works as presence It is PSNR that PSNR, which is unsatisfactory for preset first quality judging condition,>When MINPSNR, by QP-1, and it is single according to MINPSNR, coding QP after elemental size, reduction re-starts coding to coding unit to be encoded, until coding result meets preset first matter Measure decision condition.When PSNR meets preset first quality judging condition, and it is unsatisfactory for preset second mass there are PSNR and sentences When fixed condition is PSNR-MINPSNR≤2, by QP+1, and according to the QP after MINPSNR, coding unit size, increase, volume is treated The coding unit of code re-starts coding, until coding result meets the first quality judging condition, the second quality judging condition.

In cataloged procedure compared with the prior art, the quantization parameter of coding unit to be encoded is fixed value, the present invention Embodiment can adaptively be changed according to subjective model PSNR, the first quality judging condition and the second quality judging condition and wait compiling The quantization parameter of the coding unit of code reduces the distortion of unit to be encoded, obtains the first quality judging condition and the second mass is sentenced Under fixed condition limitation, ensures coding quality and the higher coding result of compression efficiency, waited for each using the embodiment of the present invention The coding unit of coding is encoded, and the coding unit to be encoded for being unsatisfactory for quality judging condition to there is distortion in time carries out It recompiles, can avoid to after the completion of coding unit coding all to be encoded, being recompiled due to being distorted larger whole The case where.The embodiment of the present invention makes entire coded sequence by the limitation in an encoding process to coding unit coding loss Coding loss is kept in a certain range, and then the compression effect of coding can be improved under the conditions of meeting subjective model PSNR Rate.Therefore, the embodiment of the present invention can improve code efficiency and the compression efficiency of coding, disclosure satisfy that specific application scene to compiling The demand of code quality.

Referring to Fig. 5, Fig. 5 is a kind of structure chart of the code device based on adaptive quantizing parameter of the embodiment of the present invention, Including：

Acquisition module 501, the quantization parameter for obtaining coding unit to be encoded.

Coding module 502, for according to preset quality threshold, preset coding unit size, quantization parameter, treating volume The coding unit of code is encoded, and obtains the coding result of coding unit to be encoded, coding result includes multiple mass figures.

First determination module 503, for comparing mass figures and quality threshold, when there are a mass figures be unsatisfactory for it is pre- If the first quality judging condition when, quantization parameter is reduced, and according to the quantization after quality threshold, coding unit size, reduction Parameter re-starts coding to coding unit to be encoded, until coding result meets preset first quality judging condition.

Second determination module 504 meets preset first quality judging condition for working as all mass figures, and there are one When a mass figures are unsatisfactory for preset second quality judging condition, increase quantization parameter, and according to quality threshold, coding unit Quantization parameter after size, increase re-starts coding to coding unit to be encoded, until coding result meets the first mass Decision condition, the second quality judging condition.

Code device provided in an embodiment of the present invention based on adaptive quantizing parameter, is added preset in an encoding process Quality threshold, after the coding result for obtaining coding unit to be encoded, compare in coding result multiple mass figures with it is preset Quality threshold, when being unsatisfactory for preset first quality judging condition there are a mass figures, reduction quantization parameter, and according to Quantization parameter after quality threshold, coding unit size, reduction re-starts coding to coding unit to be encoded, until compiling Code result meets preset first quality judging condition.When all mass figures meet preset first quality judging condition, and When being unsatisfactory for preset second quality judging condition there are a mass figures, increase quantization parameter, and according to quality threshold, volume Code unit size, the quantization parameter after increase, coding is re-started to coding unit to be encoded, until coding result satisfaction the One quality judging condition, the second quality judging condition.

In cataloged procedure compared with the prior art, the quantization parameter of coding unit to be encoded is fixed value, the present invention Embodiment can adaptively be changed to be encoded according to quality threshold, the first quality judging condition and the second quality judging condition The quantization parameter of coding unit reduces the distortion of unit to be encoded, obtains the first quality judging condition and the second quality judging item Under part limitation, ensure coding quality and the higher coding result of compression efficiency, using the embodiment of the present invention to each to be encoded Coding unit encoded, the coding unit to be encoded for being unsatisfactory for quality judging condition to there is distortion in time carries out again Coding can avoid after the completion of being encoded to coding unit all to be encoded, due to being distorted the larger feelings all recompiled Condition.Therefore, the embodiment of the present invention can improve code efficiency and the compression ratio of coding, disclosure satisfy that specific application scene to coding The demand of quality.It should be noted that the device of the embodiment of the present invention is to apply the above-mentioned coding based on adaptive quantizing parameter The device of method, then all embodiments of coding method of the above application based on adaptive quantizing parameter be suitable for the device, And it can reach same or analogous advantageous effect.

Referring to Fig. 6, Fig. 6 is another structure of the code device based on adaptive quantizing parameter of the embodiment of the present invention Figure, including：

In the embodiment of the present invention, coding module 602, including：

Submodule 6021 is predicted, for utilizing corresponding, the encoded history of frame image where coding unit to be encoded Frame image obtains the reference encoder unit of coding unit to be encoded.

Transformation submodule 6022, for obtaining coding unit to be encoded, the difference with the pixel of reference encoder unit, Difference is subjected to discrete cosine transform, obtains the frequency domain data of difference.

Quantify submodule 6023, for the relationship according to preset quantization parameter and quantization step, obtains quantization parameter pair The quantization step answered, and the frequency domain data of difference is quantified using quantization step, the coding to be encoded after being quantified The data of unit.

Entropy coding submodule 6024 carries out entropy coding for the data to the coding unit to be encoded after quantization, obtains Coding result.

In the embodiment of the present invention, the first determination module 603 is specifically used for：

When being unsatisfactory for preset first quality judging condition there are a mass figures, it is pre- that quantization parameter is reduced first If quantity.

Correspondingly, the second determination module 604, is specifically used for：

When all mass figures meet preset first quality judging condition, and there are a mass figures to be unsatisfactory for presetting The second quality judging condition when, by quantization parameter increase the first preset quantity.

In the embodiment of the present invention, the first determination module 603 is additionally operable to：

First counter, which counts, adds one, and when the number that the first counter counts is more than preset first count value, It sends and reminds instruction, wherein remind instruction to carry and count corresponding coding result in the first counter for the last time.

In the embodiment of the present invention, the second determination module 604 is additionally operable to：

Second counter, which counts, adds one, and when the number that the second counter counts is more than preset second count value, It sends and reminds instruction, wherein remind instruction to carry and count corresponding coding result in the second counter for the last time.

In the embodiment of the present invention, device further includes：

Preserving module 605, for until coding result meets preset first quality judging condition, preset second mass After decision condition, the coding result of coding unit to be encoded is preserved.

In the embodiment of the present invention, preset quality threshold is：The picture of the NxN blocks of preset reconstruction image and original image The upper limit threshold of plain mean square deviation MSD, wherein N is preset natural number.

Correspondingly, mass figures, are：The divided multiple corresponding MSD of NxN blocks of coding unit to be encoded.

Correspondingly, the first quality judging condition is, MSD is less than the upper limit threshold of MSD, and the second quality judging condition is MSD Upper limit threshold and MSD difference, be less than the first preset difference value.

In the embodiment of the present invention, preset quality threshold is：The lower threshold of Y-PSNR PSNR.

Correspondingly, mass figures, are：PSNR.

Correspondingly, the first quality judging condition is, PSNR is more than the lower threshold of PSNR, and the second quality judging condition is, The difference of the lower threshold of PSNR and PSNR is less than the second preset difference value.

Code device provided in an embodiment of the present invention based on adaptive quantizing parameter, is added preset in an encoding process Quality threshold, after the coding result for obtaining coding unit to be encoded, compare in coding result multiple mass figures with it is preset Quality threshold, when being unsatisfactory for preset first quality judging condition there are a mass figures, reduction quantization parameter, and according to Quantization parameter after quality threshold, coding unit size, reduction re-starts coding to coding unit to be encoded, until compiling Code result meets preset first quality judging condition.When all mass figures meet preset first quality judging condition, and When being unsatisfactory for preset second quality judging condition there are a mass figures, increase quantization parameter, and according to quality threshold, volume Code unit size, the quantization parameter after increase, coding is re-started to coding unit to be encoded, until coding result satisfaction the One quality judging condition, the second quality judging condition.

In cataloged procedure compared with the prior art, the quantization parameter of coding unit to be encoded is fixed value, the present invention Embodiment can adaptively be changed to be encoded according to quality threshold, the first quality judging condition and the second quality judging condition The quantization parameter of coding unit reduces the distortion of unit to be encoded, obtains the first quality judging condition and the second quality judging item Under part limitation, ensure coding quality and the higher coding result of compression efficiency, using the embodiment of the present invention to each to be encoded Coding unit encoded, the coding unit to be encoded for being unsatisfactory for quality judging condition to there is distortion in time carries out again Coding can avoid after the completion of being encoded to coding unit all to be encoded, due to being distorted the larger feelings all recompiled Condition.Therefore, the embodiment of the present invention can improve code efficiency and the compression ratio of coding, disclosure satisfy that specific application scene to coding The demand of quality.

It should be noted that the device of the embodiment of the present invention is the device using the above method, then above-mentioned all embodiments It is suitable for the device, and can reaches same or analogous advantageous effect.

It should be noted that herein, relational terms such as first and second and the like are used merely to a reality Body or operation are distinguished with another entity or operation, are deposited without necessarily requiring or implying between these entities or operation In any actual relationship or order or sequence.Moreover, the terms "include", "comprise" or its any other variant are intended to Non-exclusive inclusion, so that the process, method, article or equipment including a series of elements is not only wanted including those Element, but also include other elements that are not explicitly listed, or further include for this process, method, article or equipment Intrinsic element.In the absence of more restrictions, the element limited by sentence "including a ...", it is not excluded that There is also other identical elements in process, method, article or equipment including element.

Each embodiment in this specification is all made of relevant mode and describes, identical similar portion between each embodiment Point just to refer each other, and each embodiment focuses on the differences from other embodiments.Especially for system reality For applying example, since it is substantially similar to the method embodiment, so description is fairly simple, related place is referring to embodiment of the method Part explanation.

The above is merely preferred embodiments of the present invention, it is not intended to limit the scope of the present invention.It is all in this hair Any modification, equivalent replacement, improvement and so within bright spirit and principle, are included within the scope of protection of the present invention.

Claims (16)

1. a kind of coding method based on adaptive quantizing parameter, which is characterized in that including：

Obtain the quantization parameter of coding unit to be encoded；

According to preset quality threshold, preset coding unit size, the quantization parameter, coding unit to be encoded is carried out Coding, obtains the coding result of coding unit to be encoded, the coding result includes multiple mass figures；

Compare the mass figures and the quality threshold, when there are a mass figures to be unsatisfactory for preset first quality judging When condition, quantization parameter is reduced, and according to the quantization parameter after the quality threshold, the coding unit size, reduction, treat The coding unit of coding re-starts coding, until coding result meets the preset first quality judging condition；

When all mass figures meet preset first quality judging condition, and there are a mass figures to be unsatisfactory for preset When two quality judging conditions, increase quantization parameter, and according to the amount after the quality threshold, the coding unit size, increase Change parameter, coding is re-started to coding unit to be encoded, until coding result meets the first quality judging condition, institute State the second quality judging condition.

2. according to the method described in claim 1, it is characterized in that, described encode coding unit to be encoded, including：

Using corresponding, the encoded historical frames image of frame image where coding unit to be encoded, coding to be encoded is obtained The reference encoder unit of unit；

Coding unit to be encoded is obtained, the difference with the pixel of the reference encoder unit carries out the difference discrete Cosine transform obtains the frequency domain data of difference；

According to the relationship of preset quantization parameter and quantization step, the corresponding quantization step of quantization parameter is obtained, and described in utilization Quantization step quantifies the frequency domain data of the difference, the data of the coding unit to be encoded after being quantified；

Entropy coding is carried out to the data of the coding unit to be encoded after the quantization, obtains coding result.

3. according to the method described in claim 1, it is characterized in that, described when there are a mass figures to be unsatisfactory for preset the When one quality judging condition, quantization parameter is reduced, including：

When being unsatisfactory for preset first quality judging condition there are a mass figures, quantization parameter is reduced by the first present count Amount；

Correspondingly, described when all mass figures meet preset first quality judging condition, and there are a mass figures not When meeting preset second quality judging condition, increase quantization parameter, including：

When all mass figures meet preset first quality judging condition, and there are a mass figures to be unsatisfactory for preset When two quality judging conditions, quantization parameter is increased by the first preset quantity.

4. according to the method described in claim 3, it is characterized in that, it is described by quantization parameter reduce the first preset quantity, later, The method further includes：

First counter, which counts, adds one, and when the number that first counter counts is more than preset first count value, It sends and reminds instruction, wherein the prompting instruction carries counts corresponding coding result for the last time in the first counter.

5. according to the method described in claim 3, it is characterized in that, it is described by quantization parameter increase the first preset quantity, later, The method further includes：

Second counter, which counts, adds one, and when the number that second counter counts is more than preset second count value, It sends and reminds instruction, wherein the prompting instruction carries counts corresponding coding result for the last time in the second counter.

6. according to the method described in claim 1, it is characterized in that, described until coding result meets preset first matter Decision condition, the preset second quality judging condition are measured, later, the method further includes：

Preserve the coding result of the coding unit to be encoded.

7. according to the method described in claim 1, it is characterized in that, the preset quality threshold, is：

The upper limit threshold of the pixel mean square deviation MSD of the NxN blocks of preset reconstruction image and original image, wherein the N is default Natural number；

Correspondingly, the mass figures, are：

The divided multiple corresponding MSD of NxN blocks of coding unit to be encoded；

Correspondingly, the first quality judging condition is, MSD is less than the upper limit threshold of MSD, the second quality judging condition For the upper limit threshold of MSD and the difference of MSD are less than the first preset difference value.

8. according to the method described in claim 1, it is characterized in that, the preset quality threshold, is：

The lower threshold of Y-PSNR PSNR；

Correspondingly, the mass figures, are：

The PSNR；

Correspondingly, the first quality judging condition is, PSNR is more than the lower threshold of PSNR, the second quality judging condition For the difference of the lower threshold of PSNR and PSNR is less than the second preset difference value.

9. a kind of code device based on adaptive quantizing parameter, which is characterized in that including：

Acquisition module, the quantization parameter for obtaining coding unit to be encoded；

Coding module is used for according to preset quality threshold, preset coding unit size, the quantization parameter, to be encoded Coding unit encoded, obtain the coding result of coding unit to be encoded, the coding result includes multiple mass numbers Value；

First determination module, for the mass figures and the quality threshold, when there are a mass figures to be unsatisfactory for When preset first quality judging condition, reduce quantization parameter, and according to the quality threshold, the coding unit size, subtract Quantization parameter after few, coding is re-started to coding unit to be encoded, until coding result meets described preset first Quality judging condition；

Second determination module meets preset first quality judging condition for working as all mass figures, and there are a quality When numerical value is unsatisfactory for preset second quality judging condition, increase quantization parameter, and single according to the quality threshold, the coding Quantization parameter after elemental size, increase re-starts coding to coding unit to be encoded, until coding result meets described the One quality judging condition, the second quality judging condition.

10. device according to claim 9, which is characterized in that the coding module, including：

Submodule is predicted, for using corresponding, the encoded historical frames image of frame image where coding unit to be encoded, obtaining Take the reference encoder unit of coding unit to be encoded；

Transformation submodule, for obtaining coding unit to be encoded, the difference with the pixel of the reference encoder unit, by institute It states difference and carries out discrete cosine transform, obtain the frequency domain data of difference；

Quantify submodule, for the relationship according to preset quantization parameter and quantization step, obtains the corresponding quantization of quantization parameter Step-length, and the frequency domain data of the difference is quantified using the quantization step, the coding to be encoded after being quantified The data of unit；

Entropy coding submodule carries out entropy coding for the data to the coding unit to be encoded after the quantization, is encoded As a result.

11. device according to claim 9, which is characterized in that first determination module is specifically used for：

When being unsatisfactory for preset first quality judging condition there are a mass figures, quantization parameter is reduced by the first present count Amount；

Correspondingly, second determination module, is specifically used for：

When all mass figures meet preset first quality judging condition, and there are a mass figures to be unsatisfactory for preset When two quality judging conditions, quantization parameter is increased by the first preset quantity.

12. according to the devices described in claim 11, which is characterized in that first determination module is additionally operable to：

First counter, which counts, adds one, and when the number that first counter counts is more than preset first count value, It sends and reminds instruction, wherein the prompting instruction carries counts corresponding coding result for the last time in the first counter.

13. according to the devices described in claim 11, which is characterized in that second determination module is additionally operable to：

Second counter, which counts, adds one, and when the number that second counter counts is more than preset second count value, It sends and reminds instruction, wherein the prompting instruction carries counts corresponding coding result for the last time in the second counter.

14. device according to claim 9, which is characterized in that described device further includes：

Preserving module, for until coding result meets the preset first quality judging condition, preset second matter After measuring decision condition, the coding result of the coding unit to be encoded is preserved.

15. device according to claim 9, which is characterized in that the preset quality threshold is：

The upper limit threshold of the pixel mean square deviation MSD of the NxN blocks of preset reconstruction image and original image, wherein the N is default Natural number；

Correspondingly, the mass figures, are：

The divided multiple corresponding MSD of NxN blocks of coding unit to be encoded；

Correspondingly, the first quality judging condition is, MSD is less than the upper limit threshold of MSD, the second quality judging condition For the upper limit threshold of MSD and the difference of MSD are less than the first preset difference value.

16. device according to claim 9, which is characterized in that the preset quality threshold is：

The lower threshold of Y-PSNR PSNR；

Correspondingly, the mass figures, are：

The PSNR；

Correspondingly, the first quality judging condition is, PSNR is more than the lower threshold of PSNR, the second quality judging condition For the difference of the lower threshold of PSNR and PSNR is less than the second preset difference value.