CN101819774A - Methods and systems for coding and decoding sound source bearing information - Google Patents

Abstract

The invention discloses methods and systems for coding and decoding a sound source bearing information. By the invention, difference operation can be carried out on the angle information of each direction, corresponding to the current frame and the angle information of the same direction, corresponding to the previous frame to obtain the difference operation result of each direction; and then low-precision quantification is carried out on the difference operation result with too high value and high-precision quantification is carried out on the difference operation result with too low value, thereby realizing coding of the sound source bearing information. In such a manner, as long as being carried in the heading syntactic structure of the current frame after being coded, the sound source bearing information can be transmitted along with the code stream, thereby realizing precise sound source localization, in addition, for the difference operation result with too high value, the invention can compensate the error generated when quantifying the difference operation result of the direction.

Description

The decoding method of sound source bearing information and system

Technical field

The present invention relates to the encoding and decoding technique of voice data, particularly the coding/decoding system of the decoding method of the coding/decoding method of a kind of coding method of sound source bearing information, a kind of sound source bearing information, a kind of sound source bearing information and a kind of sound source bearing information.

Background technology

In existing some monitoring scene; usually can utilize microphone array to come audio frequency acquiring multichannel data at front monitoring front-end; utilize the microphone array algorithm that audio frequency multichannel data are carried out processing such as denoising, location then, obtain audio frequency mono channel data and sound source bearing information.

After this, can transfer to the monitoring rear end with the audio frequency mono channel data compression coding and after generating code stream based on existing audio compression coding standard, and play by decoding back, monitoring rear end.Sound source bearing information then can carry out auditory localization for the monitoring rear end, and the camera that is used for controlling in the monitoring scene rotates and/or moves, to realize the tracking to monitoring objective.

Yet existing audio compression coding standard is not supported in and transmits sound source bearing information in the code stream, thereby makes sound source bearing information to transfer to the monitoring rear end by front monitoring front-end.

In order to address the above problem, prior art then directly transfers to the monitoring rear end with the audio frequency multichannel data compression coding of microphone array collection and after generating code stream, and by utilizing the microphone array algorithm that audio frequency multichannel data are carried out processing such as denoising, location after the monitoring decoding, to obtain sound source bearing information.

But because the phase relation of each sound channel can be destroyed in the compression encoding process of front monitoring front-end in the multichannel audio data, thereby make the monitoring rear end can't obtain sound source bearing information accurately, and then can't realize auditory localization accurately.

Summary of the invention

In view of this, the invention provides the decoding method of the coding/decoding method of a kind of coding method of sound source bearing information, a kind of sound source bearing information, a kind of sound source bearing information and a kind of coding/decoding system of sound source bearing information, can support the raising of auditory localization accuracy.

The coding method of a kind of sound source bearing information provided by the invention, described sound source bearing information comprise the angle information on any direction of each audio data frame correspondence, and this coding method comprises:

C1, with the angle information of pairing each direction of present frame respectively with former frame in corresponding unidirectional angle information carry out calculus of differences, obtain the 3rd calculus of differences result of each direction;

C20, judge whether the 3rd calculus of differences result's of each direction value is positioned at outside the predetermined angular range, if, then order execution in step c21 and step c31; Otherwise, order execution in step c22 and step c32;

C21, to set this direction corresponding codes rank be first code level, utilize first order angle precision to quantize the 3rd calculus of differences result of this direction, obtain this direction the 4th calculus of differences result, and the 4th calculus of differences result of this direction is defined as result behind this orientation angle information coding;

C31, utilize counterparty in the 4th calculus of differences result, first order angle precision and the former frame to angle information, upgrade counterparty in the present frame to angle information, with compensation quantize error that the 4th calculus of differences produces as a result the time, and for encode the next frame counterparty to angle information the time use;

C22, to set this direction corresponding codes rank be second code level, utilize second level angle precision to quantize the 3rd calculus of differences result of this direction, obtain this direction the 5th calculus of differences result, and the 5th calculus of differences result of this direction is defined as result behind this orientation angle information coding;

C32, utilize counterparty in the 5th calculus of differences result, second level angle precision and the former frame to angle information, upgrade counterparty in the present frame to angle information, with compensation quantize error that the 5th calculus of differences produces as a result the time, and for encode the next frame counterparty to angle information the time use;

Wherein, second level angle precision is more than or equal to 1 and less than first order angle precision.

The coding/decoding method of a kind of sound source bearing information provided by the invention, described sound source bearing information comprises the angle information on any direction of each audio data frame correspondence, result behind each orientation angle information coding has the corresponding codes rank respectively, and this coding/decoding method comprises:

If corresponding first code level of the either direction in the present frame, this orientation angle information of then utilizing first order angle precision and in former frame, decoding and obtain, result behind this orientation angle information coding in the present frame is decoded, obtain the angle information of this direction in the present frame;

If corresponding second code level of the either direction in the present frame, this orientation angle information of then utilizing second level angle precision and in former frame, decoding and obtain, result behind this orientation angle information coding in the present frame is decoded, obtain the angle information of this direction in the present frame;

Wherein, second level angle precision is more than or equal to 1 and less than first order angle precision.

The decoding method of a kind of sound source bearing information provided by the invention, described sound source bearing information comprises the angle information on any direction of each audio data frame correspondence, and this decoding method successively comprises each step of the coding/decoding method of each step of coding method of aforesaid a kind of sound source bearing information and aforesaid a kind of sound source bearing information.

The coding/decoding system of a kind of sound source bearing information provided by the invention, described sound source bearing information comprises the angle information on any direction of each audio data frame correspondence, and this coding/decoding system comprises continuous encoder, described scrambler is used to carry out the operation of each step correspondence of the coding method of aforesaid a kind of sound source bearing information; Described demoder is used to carry out the operation of each step correspondence of the coding/decoding method of aforesaid a kind of sound source bearing information.

As seen from the above technical solution, the present invention can with the angle information of pairing each direction of present frame respectively with former frame in corresponding unidirectional angle information carry out calculus of differences, obtain the first calculus of differences result of each direction; Then the excessive calculus of differences result of value is hanged down the quantification treatment of precision, the calculus of differences result less for value carries out high-precision quantification treatment, thereby realizes the coding to sound source bearing information.Thus, as long as can transmit with code stream, thereby realize auditory localization accurately with being carried on behind the sound source bearing information coding in the syntactic structure of present frame.And for the excessive calculus of differences result of value, the present invention also can compensate the error that the calculus of differences that quantizes this direction produces as a result the time.

Description of drawings

The level that Fig. 1 comprises for sound source bearing information in the embodiment of the invention and the synoptic diagram of vertical angle;

Fig. 2 is the exemplary process diagram of compression coding and decoding method in the embodiment of the invention;

Fig. 3 is the exemplary block diagram of compression coding and decoding system in the embodiment of the invention.

Embodiment

For making purpose of the present invention, technical scheme and advantage clearer, below with reference to the accompanying drawing embodiment that develops simultaneously, the present invention is described in more detail.

Based on existing audio compression coding standard; usually can be divided into several frames in the code stream that the audio frequency mono channel data form behind compressed encoding; and for all having defined, each frame is used to carry for example coding mode again in the existing audio compression coding standard; sample frequency; port number; a syntactic structure of code stream information such as code check; therefore; in embodiments of the present invention still to the audio frequency mono channel data compression coding to form code stream; after also sound source bearing information being encoded simultaneously; be added in the syntactic structure of any frame in the code stream or multiframe; embed sound source bearing information in the code stream to be implemented in, and make sound source bearing information to transmit with code stream.Thus, as long as when decoding, from the beginning resolve the dependent parser that obtains sound source bearing information in the syntactic structure, can obtain the sound source bearing information of every frame audio frequency mono channel data correspondence.

Consider in actual applications, be not that any monitoring scene all needs to transmit auditory localization information, even if need to transmit the sound source bearing information that also not necessarily must in a syntactic structure of each frame, all add after encoding, therefore, the sound source direction sign can further be added in the embodiment of the invention in a syntactic structure, to represent whether sound source bearing information is arranged in this syntactic structure.When decoding, can judge at first whether this sound source direction sign represents in the syntactic structure sound source bearing information is arranged, if, carry out decoding again to sound source bearing information, otherwise, can skip operation to the auditory localization information decoding.

Further, consider in the practical application, also there is the corresponding identical or akin sound source bearing information of audio frequency mono channel data in the continuous multiple frames, therefore, the embodiment of the invention is in order to reduce the sound source bearing information data volume that embeds in code stream, with further saving code stream transmission bandwidth, can be in a syntactic structure of first frame of above-mentioned continuous multiple frames, the sound source direction sign is set to represent to have in the syntactic structure effective value of sound source bearing information, and in a syntactic structure of first frame, add sound source bearing information behind the compressed encoding, and in a syntactic structure of follow-up all frames except that first frame, the sound source direction sign is set to represent the invalid value of no sound source direction information in the syntactic structure, and will not be added in the syntactic structure of follow-up all frames behind the above-mentioned sound source bearing information compressed encoding.

In embodiments of the present invention, sound source bearing information can comprise horizontal direction angle information and/or vertical direction angle information.The horizontal direction angle also can be described as horizontal azimuth, is expressed as α as shown in Figure 1 in this article; The vertical direction angle also can be described as vertical pitch angle, is expressed as β as shown in Figure 1 in this article.In Fig. 1, the center, X-axis that the initial point of three coordinate axis is positioned at microphone array along the dead ahead of microphone array to extend, Y-axis is extended along the left direction of microphone array, the Z axle directly over the microphone array to extension, α in the counterclockwise direction for just, β is being upwards for just, the span of α and β is 0～359 and spends.

Like this, the syntax format that is added into behind compressed encoding in the syntactic structure of sound source bearing information can be as follows:

{

The sound source direction sign;

If the sound source direction sign is effective, then exist

{

Result behind the horizontal direction angle information coding;

Result behind the vertical direction angle information coding;

}

}

The angle information that certainly, can also comprise other any direction in the sound source bearing information.Owing to no matter be the angle information of which kind of direction, all identical to the principle of its coding, therefore, hereinafter horizontal direction angle information α and the vertical direction angle information β that just all comprises as shown in Figure 1 with sound source bearing information is that example describes.

In the practical application, can below lift three kinds of code encoding/decoding modes and be illustrated for multiple for the coded system of the sound source bearing information of act as listed above and corresponding decoding process:

1) coded system one of sound source bearing information:

A1, with horizontal direction angle information α and vertical direction angle information β divided by preset coding angular resolution δ, obtain the binary number of two N bits (N is a positive integer), i.e. horizontal direction angle information behind the coding

With the vertical direction angle information behind the coding

To realize coding to sound source bearing information.This cataloged procedure can be expressed as:

Wherein, the value of N satisfies Or further specifically satisfy

A2, alternatively, further to the N bit binary number, be to obtain behind the compressed encoding

With

Zero padding so that embed the N bit binary number have after the zero padding, be after the zero padding

With

A syntactic structure be the integer byte.

Be that example further specifies with 10 degree, 5 degree and the 1 coding angular resolution δ that spends respectively below:

When coding angular resolution δ is 10 when spending, horizontal direction angle information α and vertical direction angle information β carry out compressed encoding, are that N gets 6 that its effective range is 0～36 degree respectively with 6 bits.Suppose, obtain behind the α of 55 degree or 60 degree and the compressed coding of β

With

Be expressed as " 000110 ".

When coding angular resolution δ is 5 when spending, horizontal direction angle information α and vertical direction angle information β carry out compressed encoding, are that N gets 7 that its effective range is 0～72 degree respectively with 7 bits.Suppose, obtain after the α of 55 degree and β are encoded

With

Be expressed as " 0001011 ", and the α of 60 degree and β obtain after encoded With Be expressed as " 0001100 ".

When coding angular resolution δ is 1 when spending, horizontal direction angle information α and vertical direction angle information β carry out compressed encoding, are that N gets 9 that its effective range is 0～359 degree respectively with 9 bits.Suppose, obtain after the α of 55 degree and β are encoded With

Be expressed as " 000110111 ", and the α of 60 degree and β obtain after encoded With

Be expressed as " 000111100 ".

With horizontal direction angle information α and vertical direction angle information β according to coded system one coding after, the syntax format that is added in the syntactic structure can be as follows:

{

The sound source direction sign;

If the sound source direction sign is effective, then exist

{

}

}

Correspondingly, the decoding process one of coded system one correspondence can be expressed as:

${\mathrm{\α}}^{\text{'}}=\mathrm{Round}(\widehat{\mathrm{\α}}\×\mathrm{\δ}),$ ${\mathrm{\β}}^{\text{'}}=\mathrm{Round}(\widehat{\mathrm{\β}}\×\mathrm{\δ})$

Wherein, α ' is decoded horizontal direction angle information, the decoded vertical direction angle information of β '.

As mentioned above, horizontal direction angle information α and vertical direction angle information β can 6,7,9 etc. the bit of non-integer byte carry out compressed encoding, so in this case, with what obtain behind the compressed encoding

With

Be added in the syntactic structure, just might cause a syntactic structure is the non-integer byte.A syntactic structure of non-integer byte then easily increases the burden of decoding processing.6,7,9 bits that obtain for coding

With

Corresponding zero padding mode can be respectively referring to table 1～table 3.

Table 1

Table 2

Table 3

2) coded system two, this paper of sound source bearing information are called difference and follow the tracks of coded system.It mainly is to utilize front and back frame continuous in the code stream to distinguish correlativity between the sound source bearing information of correspondence that difference is followed the tracks of coded system, rather than as coded system one, keep the full detail of sound source bearing information itself, can further save the shared bandwidth of code stream transmission like this; And difference is followed the tracks of coded system when the maximum occurrences of code word is not enough to represent the information of described correlativity, directly represent the information of this correlativity, and in continuous multiple frames, utilize the convergence of the maximum occurrences realization of code word the information of this correlativity with the maximum occurrences of code word.

The ultimate principle that difference is followed the tracks of coded system comprises:

B1, with the angle information of pairing each direction of present frame respectively with former frame in corresponding unidirectional angle information carry out calculus of differences, obtain the first calculus of differences result of 9 bits of each direction, and the first calculus of differences result's most significant digit is a sign bit.Wherein, 9 bits described here are in order to guarantee the span between 0～359 degree, certainly, also can adopt 10,11 etc. in the practical application greater than 9 bit number.Follow-up 9 bits that occur of this paper also are so, and promptly the 9 bit reality that occur herein are all replaceable is at least 9 bits.

For this situation that comprises horizontal direction angle information α and vertical direction angle information β, current i frame pairing horizontal direction angle information α (i) and vertical direction angle information β (i) are carried out calculus of differences with former frame i-1 frame pairing horizontal direction angle information α (i-1) and vertical direction angle information β (i-1) respectively, obtain corresponding 9 bits, first calculus of differences delta_ α (i) and delta_ β (i) as a result, i is the positive integer greater than 1, first calculus of differences as a result the span of delta_ α (i) and delta_ β (i) between 0～359 degree.Wherein, the calculus of differences process in the difference tracking coded system can be expressed as:

delta_α(i)＝(α(i)-α(i-1))rem360，delta_β(i)＝(β(i)-β(i-1))rem360；

Wherein, " rem " that is occurred herein all represents to get remainder operation.

After this, again with first calculus of differences as a result the span of delta_ α (i) and delta_ β (i) be converted to ± 180 degree between, and set first calculus of differences as a result the most significant digit of delta_ α (i) and delta_ β (i) be sign bit.With first calculus of differences of horizontal direction angle information as a result delta_ α (i) be example, transfer process can be expressed as: if delta_ α (i)＞180, then delta_ α (i)=delta_ α (i)-360.

B2, for the bit number that reduces by the first calculus of differences result, to save the shared bandwidth of code stream, utilize preset coding angular resolution δ to quantize the first calculus of differences result of each direction, obtain the second calculus of differences result of the M bit of each direction, and the second calculus of differences result of each direction can be defined as the result behind this orientation angle information coding respectively.The second calculus of differences result's most significant digit is a sign bit, and M is positive integer, 0＜M＜9,

δ is the positive integer more than or equal to 1.

In the practical application, can judge earlier whether the first calculus of differences result's of each direction value is enough to represent with the M bit, for example judge each direction the first calculus of differences result value whether ± (2 ^M-1-1) between the δ; If the first calculus of differences result's of either direction value be enough to the M bit represent, for example the first calculus of differences result of this direction value ± (2 ^M-1-1) between the δ, then calculates the merchant of the first calculus of differences result of this direction, and this merchant is defined as the second calculus of differences result of this direction divided by coding angular resolution δ; If the first calculus of differences result's of either direction value be not enough to the M bit represent, for example the first calculus of differences result's of this direction value is greater than (2 ^M-1-1) δ or less than-(2 ^M-1-1) δ, then with the M bit the extreme value that can represent be defined as the second calculus of differences result of this direction.

For this situation that comprises horizontal direction angle information α and vertical direction angle information β, utilize preset coding angular resolution δ to quantize first calculus of differences delta_ α (i) and delta_ β (i) as a result, obtain span ± (2 ^M-1The second calculus of differences result of the horizontal direction after the quantification-1)

The second calculus of differences result with vertical direction

And

With

Can be added in the syntactic structure as the result behind result behind the horizontal direction angle information coding and the vertical direction angle information coding respectively.

With the calculus of differences of horizontal direction angle information as a result delta_ α (i) be example, the quantizing process that its corresponding difference is followed the tracks of in coded system can be expressed as:

$\left\{\begin{array}{cc}\widehat{\mathrm{delta}\_\mathrm{\&alpha;}\left(i\right)}=\mathrm{round}(\mathrm{delta}\_\mathrm{\&alpha;}\left(i\right)/\mathrm{\&delta;}),& 0\&le;\mathrm{delta}\_\mathrm{\&alpha;}\left(i\right)\&le;(2^{M-1}-1)\mathrm{\&delta;}\\ \widehat{\mathrm{delta}\_\mathrm{\&alpha;}\left(i\right)}=-\mathrm{round}(-\mathrm{delta}\_\mathrm{\&alpha;}\left(i\right)/\mathrm{\&delta;}),& -(2^{M-1}-1)\mathrm{\&delta;}\&le;\mathrm{delta}\_\mathrm{\&alpha;}\left(i\right)<0\\ \widehat{\mathrm{delta}\_\mathrm{\&alpha;}\left(i\right)}=(2^{M-1}-1),& (2^{M-1}-1)\mathrm{\&delta;}<\mathrm{delta}\_\mathrm{\&alpha;}\left(i\right)\&le;180\\ \widehat{\mathrm{delta}\_\mathrm{\&alpha;}\left(i\right)}=-(2^{M-1}-1),& -180<\mathrm{delta}\_\mathrm{\&alpha;}\left(i\right)<-(2^{M-1}-1)\mathrm{\&delta;}\end{array}\right.$

Perhaps, this quantizing process can further be expressed as simplifiedly:

$\left\{\begin{array}{cc}\widehat{\mathrm{delta}\_\mathrm{\&alpha;}\left(i\right)}=\mathrm{round}(\mathrm{delta}\_\mathrm{\&alpha;}\left(i\right)/\mathrm{\&delta;}),& -(2^{M-1}-1)\mathrm{\&delta;}\&le;\mathrm{delta}\_\mathrm{\&alpha;}\left(i\right)\&le;(2^{M-1}-1)\mathrm{\&delta;}\\ \widehat{\mathrm{delta}\_\mathrm{\&alpha;}\left(i\right)}=(2^{M-1}-1),& (2^{M-1}-1)\mathrm{\&delta;}<\mathrm{delta}\_\mathrm{\&alpha;}\left(i\right)\&le;180\\ \stackrel{}{\mathrm{delta}\_\mathrm{\&alpha;}\left(i\right)}=-(2^{M-1}-1),& -180<\mathrm{delta}\_\mathrm{\&alpha;}\left(i\right)<-(2^{M-1}-1)\mathrm{\&delta;}\end{array}\right.$

In like manner, the calculus of differences of vertical direction angle information as a result the pairing quantizing process of delta_ β (i) also be like this.

B3, based on above-mentioned quantification manner, greater than 1 o'clock, all can there be error in the second calculus of differences result who utilizes coding angular resolution δ to quantize each direction of obtaining at coding angular resolution δ; Equaling at 1 o'clock at the coding angular resolution, value is positioned at ± and (2 ^M-1-1) the first calculus of differences result outside the δ after quantizing can be by indirect assignment ± (2 ^M-1-1) thereby also can there be error.Therefore, for the both of these case that has error, utilize the counterparty to the second calculus of differences result, coding angular resolution δ and former frame in the angle information of corresponding this direction, upgrade the present frame counterparty to angle information, the error that first calculus of differences that quantizes this direction in order to compensation produces as a result the time, and use during for the angle information of this direction of the next frame correspondence of encoding.

For this situation that comprises horizontal direction angle information α and vertical direction angle information β, the second calculus of differences result who obtains after the amount usableization

And/or

The horizontal direction angle information α (i-1) and the vertical direction angle information β (i-1) of coding angular resolution δ and former frame correspondence, upgrade the horizontal direction angle information α (i) and/or the vertical direction angle information β (i) of present frame correspondence, the error that produces when quantizing delta_ α (i) and/or delta_ β (i), and use during for the horizontal direction angle information α (i+1) of coding next frame correspondence and vertical direction angle information β (i+1) with compensation.

To upgrade horizontal direction angle information α (i) is example, and the renewal process that difference is followed the tracks of in the coded system can be expressed as:

If

Most significant digit for just, if promptly

Then upgrade

If

Most significant digit for negative, if promptly

Then upgrade

Perhaps, this renewal process can further be expressed as simplifiedly:

$\mathrm{\&alpha;}\left(i\right)=(\mathrm{\&alpha;}(i-1)+\mathrm{\&delta;}\&times;\widehat{\mathrm{delta}\_\mathrm{\&alpha;}\left(i\right)})\mathrm{rem}360.$

Because the horizontal direction angle information α (i) of each frame correspondence and vertical direction angle information β (i) all upgrade in the manner described above, use during for the horizontal direction angle information α (i+1) of coding next frame correspondence and vertical direction angle information β (i+1), thereby foregoing error can not accumulated.

With horizontal direction angle information α and vertical direction angle information β according to coded system two, be difference tracking mode coding after, the syntax format that is added in the syntactic structure all can be as follows:

{

The sound source direction sign;

If the sound source direction sign is effective, then exist

{

$\widehat{\mathrm{delta}\_\mathrm{\&alpha;}\left(i\right)};$

$\widehat{\mathrm{delta}\_\mathrm{\&beta;}\left(i\right)};$

}

}

Correspondingly, difference follows the tracks of coded system, be the angle information that the decoding process two of coded system two correspondences can utilize coding angular resolution δ and each direction that decoding obtains in former frame, the second calculus of differences result to unidirectional M bit in the present frame decodes respectively, obtains the angle information of each direction in the present frame.

With the result behind the horizontal direction angle information coding

Be example, difference follows the tracks of coded system, be that second the decoding process of coded system two correspondences utilizes coding angular resolution δ and decoding obtains in former frame horizontal direction angle information α (i-1) ', to this

Decoding obtains the horizontal direction angle information α (i) ' in the present frame, specifically is expressed as:

If

Most significant digit for just, if promptly

Then decoded horizontal direction angle information

If Most significant digit for negative, if promptly

Then decoded horizontal direction angle information

Perhaps, this decoding process two can further be expressed as simplifiedly:

Decoded horizontal direction angle information

Certainly, for the ease of the location of decoding end, above-mentioned decoding process two also can be set the span of angle information of each direction of obtaining of decoding between ± 180 degree.

As previously mentioned because coding the time can utilize aforementioned renewal process to eliminate the accumulation of error, and also can be during decoding based on the principle of this renewal process, utilize calculus of differences result after quantizing simultaneously

And the horizontal direction angle information α (i-1) ' that former frame decoding obtains decodes, thereby at most only needs

Frame can be realized decoding and obtain the convergence of accurate angle information.Wherein, angular resolution δ is big more for coding, and foregoing error will be big more, but speed of convergence can be fast more, be that T is more little.

And the ultimate principle of decoding process two is identical with the ultimate principle of renewal process in the coded system two, thus the renewal process in the coded system two can regard as with decoding end synchronously.

Below, for the encoding-decoding process of above-mentioned difference tracking mode, with the result behind the horizontal direction angle information coding

Be example, suppose that coding angular resolution δ gets 5, M gets 4 (can so that the result behind horizontal direction and the vertical direction coding only accounts for 1 byte altogether), the example that develops simultaneously describes.

Earlier the pairing horizontal direction angle information of present frame α (i) and the pairing horizontal direction angle information of former frame α (i-1) are carried out calculus of differences, and the most significant digit of α (i-1) is a sign bit.

Quantize calculus of differences delta_ α (i) as a result then, obtain the horizontal direction calculus of differences result of span after the quantification between ± 7

$\left\{\begin{array}{cc}\widehat{\mathrm{delta}\_\mathrm{\&alpha;}\left(i\right)}=\mathrm{round}(\mathrm{delta}\_\mathrm{\&alpha;}\left(i\right)/5),& 0\&le;\mathrm{delta}\_\mathrm{\&alpha;}\left(i\right)\&le;35\\ \widehat{\mathrm{delta}\_\mathrm{\&alpha;}\left(i\right)}=1000+\mathrm{round}(-\mathrm{delta}\_\mathrm{\&alpha;}\left(i\right)/5),& -35\&le;\mathrm{delta}\_\mathrm{\&alpha;}\left(i\right)<0\\ \widehat{\mathrm{delta}\_\mathrm{\&alpha;}\left(i\right)}=0111,& 35<\mathrm{delta}\_\mathrm{\&alpha;}\left(i\right)\&le;180\\ \widehat{\mathrm{delta}\_\mathrm{\&alpha;}\left(i\right)}=1111& -180<\mathrm{delta}\_\mathrm{\&alpha;}\left(i\right)<-35\end{array}\right.$

Utilize the calculus of differences result after quantizing again

And the horizontal direction angle information α (i-1) of former frame correspondence, the horizontal direction angle information α (i) of renewal present frame correspondence:

$\mathrm{\&alpha;}\left(i\right)=(\mathrm{\&alpha;}(i-1)+5\&times;\widehat{\mathrm{delta}\_\mathrm{\&alpha;}\left(i\right)})\mathrm{rem}360.$

After this, can according to

Decode, and warp

Frame can be realized decoding and obtain the convergence of accurate angle.

Need to prove, span with the first calculus of differences result when carrying out calculus of differences is converted to ± 180 degree between, and the most significant digit of setting the first calculus of differences result is that the sign bit and the second calculus of differences result's most significant digit is a sign bit, has been mainly decoding end and can realizes accurate location more quickly after decoding.Suppose that coding angular resolution δ gets 5, M gets 4, the first calculus of differences result of either direction is 350 degree, so the Dui Ying second calculus of differences result just has only 7 degree, and decoding end decoding back just can only rotate up 35 degree in pros, just needs 10 frames can realize convergence thus; And if the first calculus of differences result is quantized between ± 180 degree, still hypothesis coding angular resolution δ gets 5, M gets 4, the first calculus of differences result of either direction 350 degree will become-10 degree, so the Dui Ying second calculus of differences result just also is-2 degree, decoding end decoding back just directly rotates up 10 degree at losing side can realize accurate location, thereby need not the convergence of subsequent frame.

In addition, more preferably, consider in the specific implementation of difference tracking coded system such as the described aforementioned quantizing process of b2,00...00,10...00 represent respectively positive and negative 0 the degree, obviously wasted the code word that can be used for encoding, therefore, in embodiments of the present invention, difference is followed the tracks of coded system and can be adopted the specific implementation of another kind of quantizing process to be replaced.

The specific implementation of another kind of quantizing process is utilized 10...00, promptly 2 ^M-1Expression 180 degree, if the first calculus of differences result's of either direction value is not enough to represent with the M bit, and the first calculus of differences result of this direction is not approaching ± 180 degree, then with the M bit the extreme value that can represent be defined as the second calculus of differences result of the M bit of this direction; If the first calculus of differences result's of either direction value is not enough to represent with the M bit, and the first calculus of differences result of this direction approaching ± 180 degree, then will represent the 180 special code words of spending 2 ^M-1Be defined as the second calculus of differences result of the M bit of this direction.

For this situation that comprises horizontal direction angle information α and vertical direction angle information β, delta_ α (i) and delta_ β (i) with approaching ± 180 degree in quantizing process are quantified as the 10...00 that expression 180 is spent.Like this, than with approaching ± 180 the degree delta_ α (i) and delta_ β (i) be quantified as ± (2 ^M-1-1) Du aforementioned quantizing process, it is littler that the delta_ α (i) of approaching ± 180 degree and delta_ β (i) are quantified as the errors that 10...00 produced that expression 180 spends, thereby make speed of convergence faster.

Specifically, with the calculus of differences of horizontal direction angle information as a result delta_ α (i) be example, absolute value is defined as approaching ± 180 degree, γ 〉=90 greater than default extreme angles γ, the specific implementation that so the delta_ α (i) of approaching ± 180 degree and delta_ β (i) is quantified as the another kind of quantizing process of the 10...00 that expression 180 spends can be expressed as:

$\left\{\begin{array}{cc}\widehat{\mathrm{delta}\_\mathrm{\&alpha;}\left(i\right)}=\mathrm{round}(\mathrm{delta}\_\mathrm{\&alpha;}\left(i\right)/\mathrm{\&delta;}),& 0\&le;\mathrm{delta}\_\mathrm{\&alpha;}\left(i\right)\&le;(2^{M-1}-1)\mathrm{\&delta;}\\ \widehat{\mathrm{delta}\_\mathrm{\&alpha;}\left(i\right)}=-\mathrm{round}(-\mathrm{delta}\_\mathrm{\&alpha;}\left(i\right)/\mathrm{\&delta;}),& -(2^{M-1}-1)\mathrm{\&delta;}\&le;\mathrm{delta}\_\mathrm{\&alpha;}\left(i\right)<0\\ \widehat{\mathrm{delta}\_\mathrm{\&alpha;}\left(i\right)}=(2^{M-1}-1),& (2^{M-1}-1)\mathrm{\&delta;}<\mathrm{delta}\_\mathrm{\&alpha;}\left(i\right)\&le;\mathrm{\&gamma;}\\ \widehat{\mathrm{delta}\_\mathrm{\&alpha;}\left(i\right)}=-(2^{M-1}-1),& -\mathrm{\&gamma;}<\mathrm{delta}\_\mathrm{\&alpha;}\left(i\right)<-(2^{M-1}-1)\mathrm{\&delta;}\\ \widehat{\mathrm{delta}\_\mathrm{\&alpha;}\left(i\right)}=2^{M-1},& |\mathrm{delta}\_\mathrm{\&alpha;}\left(i\right)|>\mathrm{\&gamma;}\end{array}\right.$

Perhaps, this quantizing process can further be expressed as simplifiedly:

$\left\{\begin{array}{cc}\widehat{\mathrm{delta}\_\mathrm{\&alpha;}\left(i\right)}=\mathrm{round}(\mathrm{delta}\_\mathrm{\&alpha;}\left(i\right)/\mathrm{\&delta;}),& -(2^{M-1}-1)\mathrm{\&delta;}\&le;\mathrm{delta}\_\mathrm{\&alpha;}\left(i\right)\&le;(2^{M-1}-1)\mathrm{\&delta;}\\ \widehat{\mathrm{delta}\_\mathrm{\&alpha;}\left(i\right)}=(2^{M-1}-1),& (2^{M-1}-1)\mathrm{\&delta;}<\mathrm{delta}\_\mathrm{\&alpha;}\left(i\right)\&le;\mathrm{\&gamma;}\\ \widehat{\mathrm{delta}\_\mathrm{\&alpha;}\left(i\right)}=-(2^{M-1}-1),& -\mathrm{\&gamma;}<\mathrm{delta}\_\mathrm{\&alpha;}\left(i\right)<-(2^{M-1}-1)\mathrm{\&delta;}\\ \widehat{\mathrm{delta}\_\mathrm{\&alpha;}\left(i\right)}=2^{M-1},& |\mathrm{delta}\_\mathrm{\&alpha;}\left(i\right)|>\mathrm{\&gamma;}\end{array}\right.$

In like manner, the calculus of differences of vertical direction angle information as a result the specific implementation of the pairing another kind of quantizing process of delta_ β (i) also be like this.

Still hypothesis coding angular resolution δ gets 5, M gets 4, and hypothesis γ gets 90 degree, and with the calculus of differences of horizontal direction angle information as a result delta_ α (i) be example, then the specific implementation of another kind of quantizing process can be expressed as:

$\left\{\begin{array}{cc}\widehat{\mathrm{delta}\_\mathrm{\&alpha;}\left(i\right)}=\mathrm{round}(\mathrm{delta}\_\mathrm{\&alpha;}\left(i\right)/5),& 0\&le;\mathrm{delta}\_\mathrm{\&alpha;}\left(i\right)\&le;35\\ \widehat{\mathrm{delta}\_\mathrm{\&alpha;}\left(i\right)}=1000+\mathrm{round}(-\mathrm{delta}\_\mathrm{\&alpha;}\left(i\right)/5),& -35\&le;\mathrm{delta}\_\mathrm{\&alpha;}\left(i\right)<0\\ \widehat{\mathrm{delta}\_\mathrm{\&alpha;}\left(i\right)}=0111,& 35<\mathrm{delta}\_\mathrm{\&alpha;}\left(i\right)\&le;90\\ \widehat{\mathrm{delta}\_\mathrm{\&alpha;}\left(i\right)}=1111,& -90\&le;\mathrm{delta}\_\mathrm{\&alpha;}\left(i\right)<-35\\ \widehat{\mathrm{delta}\_\mathrm{\&alpha;}\left(i\right)}=1000,& |\mathrm{delta}\_\mathrm{\&alpha;}\left(i\right)|>90\end{array}\right.$

Difference in the embodiment of the invention is followed the tracks of coded system than coded system one, all has following advantage:

When certain sound source sounding and when mobile, the move angle in the short time interval is all less usually, has only when the sound source sounding of another position and when replacing this sound source, the redirect of wide-angle can take place.Therefore, no matter adopt any quantizing process, even if with the span of delta_ α (i) and delta_ β (i) quantize ± (2 ^M-1-1) between, still can obtain angle information accurately immediately in most cases, when having only the redirect that above-mentioned wide-angle takes place, just be in the tracking convergence state, and this speed of convergence be very fast in decoding end.Thus, under the situation that does not influence the auditory localization accuracy of information, difference is followed the tracks of coded system can reduce the shared bandwidth of code stream than coded system one.

And coded system one needed bit number depends on the size of angle, and the big more code word bits number that then needs of angle is many more, for example for ± (2 ^M-1-1) angle outside the δ angular range, the code word bits number that coded system one needs is necessarily greater than M, so for the code word bits number of the required code word of unified all angles, to guarantee constant code check, coded system one is merely able to set according to the maximum occurrences of angle the bit number of code word, thereby the code word bits number that needs can be many.Therefore, difference is followed the tracks of coded system can reduce the bit number of code word than coded system one, thereby reduces the required bandwidth of code stream.Further, get 4 and when the sound source direction sign was not set, the result behind horizontal direction and the vertical direction coding only accounted for 1 byte altogether as M.

Alternatively, consider that the angle information that decoding obtains when following the tracks of convergence is inaccurate, decoding end can think it transition result and abandon, the code word of the transition result when convergence state is followed the tracks of in expression comprises ± and (2 ^M-1-1), 2 ^M-1When decoding end can other code words occur by the time, obtain angle information accurately again.

3) coded system three, and this paper is called difference hierarchical coding mode.Difference hierarchical coding mode also utilizes front and back frame continuous in the code stream to distinguish correlativity between the corresponding sound source bearing information, rather than as coded system one, keeping the full detail of sound source bearing information itself, it is basic identical that this point and difference are followed the tracks of coded system.But the difference of following the tracks of coded system with difference is, difference hierarchical coding mode is when the code word in predetermined bit is not enough to represent the information of described correlativity, reduce the represented angle precision of code word realizing coarse positioning by first code level, and in subsequent frame, recover the represented angle precision of code word, to realize fine positioning by second code level.

Preferably, Q can be set equate, so that first code level is identical with the code check of second code level with q; If Q and q are unequal, but need still to guarantee that first code level is identical with the code check of second code level, then can be during greater than q at Q, further the q bit codewords of first code level is mended respective numbers 0 or represent the respective numbers bit of other information; At Q during, further the Q bit codewords of second code level is mended respective numbers 0 or represent the respective numbers bit of other information less than q.

Specifically, for difference hierarchical coding mode, 360 degree can be divided into P unit angular interval, each unit angular interval comprises

Degree, and for predetermined Q bit, 2 ^Q-1＜P＜2 ^q, P is for can be by 360 positive integers that divide exactly,

Preferably, the value of P should be as far as possible near 2 ^q, and/or

As far as possible near (2 ^Q-1* θ), with the q bit codewords of utilizing first code level more fully and the Q bit codewords of second code level.

Wherein, the value of P unit angular interval, promptly Spend, can regard the first order angle precision of the first code level correspondence as, in the cataloged procedure of first code level, can utilize so

The degree first order angle precision, to be positioned at ± (2 ^Q-1* θ) the calculus of differences outside the angular range as a result in the span of quantification treatment to 0～P, so that the q bit that quantizes to obtain is enough to represent the information of the described correlativity among the calculus of differences result, in order to realize coarse positioning.

Correspondingly, big or small arbitrarily angle θ then can regard the second level angle precision of the second code level correspondence as in each unit angular interval, in the cataloged procedure of second code level, only need to be positioned at ± (2 ^Q-1* θ) the calculus of differences result within the angular range, according to value more than or equal to 1 degree and less than

The second level angle precision θ quantification treatment of degree is to ± 2 ^Q-1Span in so that the Q bit that quantizes to obtain is enough to represent the information of the described correlativity among the calculus of differences result, in order to realize fine positioning.As long as

First code level quantization error maximum value that might produce so

Just can not cause to enter the state of second code level.

In the practical application, the concrete value of second level angle precision θ can also be selected with reference to value and the actual needs of P, q, Q.Suppose that P gets 30, q gets 5, Q is identical with q if desired also gets 5, then needs selected second level angle precision θ to get 1; Suppose that again P gets 30, q gets 5, Q then needs selected second level angle precision θ to get 2 less than q and get 4 if desired; Suppose that again P gets 12, q gets 4, Q is identical with q if desired also gets 4, then needs selected second level angle precision θ to get 5.That is to say, what further satisfy

Under the situation, can make Q equate with q.Preferably, second level angle precision θ gets 1, can utilize the Q bit codewords the most fully like this, so that the degree of accuracy of fine positioning is the highest.

The ultimate principle of above-mentioned difference hierarchical coding mode comprises:

C1, with the angle information of pairing each direction of present frame respectively with former frame in corresponding unidirectional angle information carry out calculus of differences, obtain the 3rd calculus of differences result of 9 bits (or at least 9 bits) of each direction, and the 3rd calculus of differences result there is not sign bit.

For this situation that comprises horizontal direction angle information α and vertical direction angle information β, current i frame pairing horizontal direction angle information α (i) and vertical direction angle information β (i) are carried out calculus of differences with former frame i-1 frame pairing horizontal direction angle information α (i-1) and vertical direction angle information β (i-1) respectively, obtain the 3rd corresponding calculus of differences delta_ α (i) and delta_ β (i) as a result, i is the positive integer greater than 1, and the 3rd calculus of differences as a result the span of delta_ α (i) and delta_ β (i) between 0～359 degree.Wherein, the calculus of differences process in the difference tracking coded system can be expressed as:

delta_α(i)＝(α(i)-α(i-1))rem360；delta_β(i)＝(β(i)-β(i-1))rem360。

C2, judge whether the 3rd calculus of differences result's of each direction value is positioned at predetermined angular range ± (2 ^Q-1* θ) outside, promptly whether be enough to represent with the Q bit.In the practical application, whether the difference that can judge the 3rd calculus of differences result's the value of each direction and 360 degree and the 3rd calculus of differences result of each direction is all more than or equal to (2 ^Q-1* θ), if the 3rd calculus of differences result's of the 3rd calculus of differences result's of either direction value and 360 degree and this direction difference is all more than or equal to (2 ^Q-1* θ), represent that then this direction the 3rd calculus of differences result's value is positioned at outside the predetermined angular range, be not enough to represent with the Q bit; If the 3rd calculus of differences result's of the 3rd calculus of differences result's of either direction value or 360 degree and this direction difference is less than (2 ^Q-1* θ), represent that then this direction the 3rd calculus of differences result's value is positioned within the predetermined angular range, be enough to represent with the Q bit.

If the 3rd calculus of differences result's of either direction value is positioned at outside the predetermined angular range, then sets first code level of this direction corresponding codes rank, and utilize for the expression coarse positioning

The first order angle precision of degree quantizes the 3rd calculus of differences result of this direction, for example is quantified as

The multiple of degree obtains q bit the 4th calculus of differences result of this direction, and the 4th calculus of differences result of this direction is defined as result behind this orientation angle information coding, and the 4th calculus of differences result does not have sign bit.

If the 3rd calculus of differences result's of either direction value is positioned within the predetermined angular range, then set second code level of this direction corresponding codes rank for the expression coarse positioning, and utilize more than or equal to 1 and less than

The second level angle precision θ of degree quantizes the 3rd calculus of differences result of this direction, obtain Q bit the 5th calculus of differences result of this direction, and the 5th calculus of differences result of this direction is defined as result behind this orientation angle information coding, the 5th calculus of differences result's most significant digit is a sign bit.

For comprising horizontal direction angle information α and vertical direction angle information β and Q bit most significant digit is this situation of sign bit, whether the difference of judging delta_ α (i) and 360 degree and delta_ α (i) is all more than or equal to (2 ^Q-1* θ), and judge that whether delta_ β (i) and 360 degree and the difference of delta_ β (i) are all more than or equal to (2 ^Q-1* θ).

If delta_ α (i) and the difference of 360 degree and the poor and/or delta_ β (i) of delta_ α (i) and 360 degree and delta_ β (i) all more than or equal to (2 ^Q-1* θ), then represent this delta_ α (i) and/or delta_ β (i) be positioned at ± (2 ^Q-1* θ) outside the angular range and be not enough to represent with the Q bit, thereby set this delta_ α (i) and/or delta_ β (i) corresponding codes rank first code level, and this delta_ α (i) and/or delta_ β (i) are quantified as for the expression coarse positioning

The multiple of degree, with the 3rd calculus of differences of horizontal direction angle information as a result delta_ α (i) be example, this process can be expressed as:

Level_α(i)＝1，

$\widehat{\mathrm{delta}\_\mathrm{\&alpha;}\left(i\right)}=\mathrm{round}(\mathrm{delta}\_\mathrm{\&alpha;}\left(i\right)/\left(\frac{360}{P}\right)),$ delta_α(i)≥2 ^Q-1×θ、360-delta_α(i)≥2 ^Q-1×θ。

If delta_ α (i) and/or delta_ β (i) less than 2 ^Q-1, or the difference of 360 degree and delta_ α (i) and/or delta_ β (i) less than (2 ^Q-1* θ), then represent this delta_ α (i) and/or delta_ β (i) be positioned at ± (2 ^Q-1* θ) in the angular range and be enough to represent with the Q bit, thereby set this delta_ α (i) and/or delta_ β (i) corresponding codes rank second code level for the expression fine positioning, and utilize second level angle precision θ to quantize this delta_ α (i) and/or delta_ β (i) earlier, then the span with this delta_ α (i) and/or delta_ β (i) quantized result be converted to ± 2 ^Q-1Within the angular range so that its most significant digit is a sign bit, thereby obtain the 5th calculus of differences result as coding back result

And/or

When delta_ α (i) and/or delta_ β (i) less than (2 ^Q-1* θ) time, can calculate this

And/or

Merchant with second level angle precision θ.With the calculus of differences of horizontal direction angle information as a result delta_ α (i) be example, this quantizing process can be expressed as:

Level_α(i)＝0， $\widehat{\mathrm{delta}\_\mathrm{\&alpha;}\left(i\right)}=\mathrm{delta}\_\mathrm{\&alpha;}\left(i\right)/\mathrm{\&theta;},$ delta_α(i)＜2 ^Q-1×θ。

Get a kind of special circumstances of 1 for second level angle precision θ, this quantizing process can be equivalent to directly this delta_ α (i) and/or delta_ β (i) are defined as the 5th calculus of differences result as coding back result

And/or

When 360 degree and the difference of delta_ α (i) less than (2 ^Q-1* θ) time, can calculate this

And/or

With the merchant of 360 differences of spending divided by second level angle precision θ.With the calculus of differences of horizontal direction angle information as a result delta_ α (i) be example, this quantizing process can be expressed as:

Level_α(i)＝0， $\widehat{\mathrm{delta}\_\mathrm{\&alpha;}\left(i\right)}=(\mathrm{delta}\_\mathrm{\&alpha;}\left(i\right)-360)/\mathrm{\&theta;},$ 360-delta_α(i)＜2 ^Q-1×θ。

Get a kind of special circumstances of 1 for second level angle precision θ, this quantizing process can be equivalent to directly should

And/or Poor with 360 degree is defined as the 5th calculus of differences result as coding back result

And/or With the calculus of differences of horizontal direction angle information as a result delta_ α (i) be example, the above-mentioned quantizing process of equivalence can be expressed as:

$\widehat{\mathrm{delta}\_\mathrm{\&alpha;}\left(i\right)}=(\mathrm{delta}\_\mathrm{\&alpha;}\left(i\right)-360),$ 360-delta_α(i)＜2 ^Q-1×θ。

In like manner, the calculus of differences of vertical direction angle information as a result the pairing quantizing process of delta_ β (i) also be like this.

C3, based on above-mentioned quantification manner, the first code level utilization

Degree quantizes, thereby can produce error, and when second level angle precision θ greater than 1 the time, second code level utilizes second level angle precision θ to quantize also can produce error.Therefore, in order to compensate the error that first code level exists, can utilize the counterparty to the 4th calculus of differences result, first order angle precision

In degree and the former frame counterparty to angle information, upgrade the present frame counterparty to angle information, for coding next frame counterparty to angle information the time use; In order to compensate the error that second code level exists, can utilize the counterparty to the 5th calculus of differences result, second level angle precision θ and former frame in the counterparty to angle information, upgrade the present frame counterparty to angle information, for coding next frame counterparty to angle information the time use.

To upgrade horizontal direction angle information α (i) is example, and when using first code level, the renewal process in the difference hierarchical coding mode can be expressed as:

$\mathrm{\&alpha;}\left(i\right)=(\mathrm{\&alpha;}(i-1)+\frac{360}{P}\&times;\widehat{\mathrm{delta}\_\mathrm{\&alpha;}\left(i\right)})\mathrm{rem}360;$

When using second code level, the renewal process in the difference hierarchical coding mode can be expressed as:

$\mathrm{\&alpha;}\left(i\right)=(\mathrm{\&alpha;}(i-1)+\mathrm{\&theta;}\&times;\widehat{\mathrm{delta}\_\mathrm{\&alpha;}\left(i\right)})\mathrm{rem}360.$

Because when using first code level, the angle information of each direction all can upgrade in the manner described above, for coding next frame counterparty to angle information the time use, thereby foregoing error can not accumulated.

Suppose that P gets 30, Q gets 5, second level angle precision θ gets 1, Q bit most significant digit is a sign bit, be about to 360 degree and be divided into 30 unit angular interval, each unit angular interval comprises 12 degree, and is example with horizontal direction angle information α (i), lifts an example coded system three is described.

Earlier the pairing horizontal direction angle information of present frame α (i) and the pairing horizontal direction angle information of former frame α (i-1) are carried out calculus of differences.

Whether the difference of judging delta_ α (i) and 360 degree and delta_ α (i) then is all greater than 16.

If delta_ α (i) and 360 degree and the difference of delta_ α (i) all more than or equal to 16, then represent this delta_ α (i) be positioned at ± 16 angular ranges outside, thereby set this delta_ α (i) corresponding codes rank for the expression coarse positioning first code level and with delta_ α (i) be quantified as 12 the degree multiples, that is:

Level_α(i)＝1，

$\widehat{\mathrm{delta}\_\mathrm{\&alpha;}\left(i\right)}=\mathrm{round}(\mathrm{delta}\_\mathrm{\&alpha;}\left(i\right)/12),$ delta_α(i)≥16、360-delta_α(i)≥16；

And upgrade the horizontal direction angle information

If delta_ is α (i) less than 16, represent that then this delta_ α (i) is positioned at ± 16 angular ranges, thereby set second code level of this delta_ α (i) corresponding codes rank, and the result after directly this delta_ α (i) being defined as encoding for the expression fine positioning

That is:

Level_α(i)＝0，

$\widehat{\mathrm{delta}\_\mathrm{\&alpha;}\left(i\right)}=\mathrm{delta}\_\mathrm{\&alpha;}\left(i\right),$ delta_α(i)＜2 ^Q-1。

If the difference of 360 degree and delta_ α (i) is less than 16, represent that then this delta_ α (i) is positioned at ± 16 angular ranges, thereby set second code level of this delta_ α (i) corresponding codes rank for the expression fine positioning, and delta_ α (i) is quantized to ± 16 scope in, that is:

Level_α(i)＝0，

$\widehat{\mathrm{delta}\_\mathrm{\&alpha;}\left(i\right)}=\mathrm{delta}\_\mathrm{\&alpha;}\left(i\right)-360,$ 360-delta_α(i)＜16。

Need to prove that the most significant digit of the q bit codewords of first code level also can be sign bit.This moment so, if delta_ α (i) and the difference of 360 degree and the poor and/or delta_ β (i) of delta_ α (i) and 360 degree and delta_ β (i) all more than or equal to 2 ^Q-1, then also need span with this delta_ α (i) and/or delta_ β (i) be converted to ± 2 ^Q-1Within the angular range, be set to sign bit with the most significant digit of this delta_ α (i) and/or delta_ β (i); Perhaps because second code level also needs the conversion of above-mentioned angular range, thereby can be after calculus of differences, judge before first code level and second code level, unified to the span with delta_ α (i) and delta_ β (i) be converted to ± 2 ^Q-1Within the angular range, be set to sign bit with the most significant digit of delta_ α (i) and delta_ β (i).

With horizontal direction angle information α and vertical direction angle information β according to coded system three, be the compression of difference hierarchical approaches after, its syntax format that is added into behind coding in the syntactic structure can be as follows:

{

The sound source direction sign;

If the sound source direction sign is effective, then exist

{

Level_α(i)；

$\widehat{\mathrm{delta}\_\mathrm{\&alpha;}\left(i\right)};$

Level_β(i)；

$\widehat{\mathrm{delta}\_\mathrm{\&beta;}\left(i\right)};$

}

}

Correspondingly, difference hierarchical coding mode, be that the decoding process three of coded system three correspondences needs to judge earlier the result's corresponding codes rank respectively behind each orientation angle information coding;

If corresponding first code level of the either direction in the present frame, this orientation angle information of then utilizing first order angle precision and in former frame, decoding and obtain, result behind this orientation angle information coding in the present frame is decoded, obtain the angle information of this direction in the present frame;

If corresponding second code level of the either direction in the present frame, this orientation angle information of then utilizing second level angle precision and in former frame, decoding and obtain, result behind this orientation angle information coding in the present frame is decoded, obtain the angle information of this direction in the present frame.

With the result behind the horizontal direction angle information coding

Being example, difference hierarchical coding mode, is that the decoding process three of coded system three correspondences can be expressed as:

Judge

Pairing code level.

If

Pairing code level is then utilized first order angle precision for first code level of expression coarse positioning

And the horizontal direction angle information α (i-1) ' that decoding obtains in former frame, to this

Decoding obtains the horizontal direction angle information α (i) ' in the present frame, specifically is expressed as:

$\mathrm{\&alpha;}{\left(i\right)}^{\text{'}}=\left(\mathrm{\&alpha;}{(i-1)}^{\text{'}}+\frac{360}{P}\&times;\widehat{\mathrm{delta}\_\mathrm{\&alpha;}\left(i\right)}\right)\mathrm{rem}360$

If

Pairing code level for the expression fine positioning second code level, then utilize more than or equal to 1 and less than The second level angle precision θ of degree and the horizontal direction angle information α (i-1) ' that decoding obtains in former frame are to this

Decoding obtains the horizontal direction angle information α (i) ' in the present frame, specifically is expressed as:

When

Most significant digit for just, promptly The time,

Decoded horizontal direction angle information

When Most significant digit for negative, promptly

The time,

Decoded horizontal direction angle information

Perhaps, if

Pairing code level is second code level of expression fine positioning, and this decoding process three can further be expressed as simplifiedly:

Decoded horizontal direction angle information

Get a kind of special circumstances of 1 for second level angle precision θ, if

Pairing code level is second code level of expression fine positioning, and then decoding process three can be expressed as equivalently:

Decoded horizontal direction angle information

In like manner, the result behind the vertical direction angle information coding

Pairing decode procedure also is like this.

And the ultimate principle of decoding process three is identical with the ultimate principle of renewal process in the coded system three, thus the renewal process in the coded system three can regard as with decoding end synchronously.

Difference hierarchical coding mode in the embodiment of the invention has following advantage than coded system one and coded system two:

When certain sound source sounding is also mobile; move angle in the short time interval is all less usually; promptly can adopt second code level to realize fine positioning usually based on second level angle precision θ; and have only when the sound source sounding of another position and when replacing this sound source; the redirect of wide-angle just can take place, and adopt based on

First code level of the first order angle precision of degree.Therefore, still can obtain angle information accurately immediately in most cases in decoding end, even if the redirect of above-mentioned wide-angle takes place and adopt first code level to realize coarse positioning, but the fine positioning of follow-up needs 1 frame can be realized convergence that speed of convergence is obviously faster than coded system two.

Suppose that P gets 30, Q gets 5, second level angle precision θ gets 1, and hypothesis:

At 0 moment, the horizontal direction angle [alpha] (0)=110 of sound source, vertical direction angle beta (0)=10;

In 1 moment, sound source position moves, horizontal direction angle [alpha] (1)=115, vertical direction angle beta (1)=5.

The encoding-decoding process of corresponding code encoding/decoding mode three can be expressed as:

First frame:

At coding side, the horizontal direction angle and the vertical direction angle of its former frame are original state 0, delta_ α (0)=(α (0)-0) rem360=110 then, delta_ β (0)=(β (0)-0) rem360=10;

Because | delta_ α (0) |＞16 and 360-|delta_ α (0) |＞16,

So Level_ α (0)=1,

And upgrade

Because | delta_ β (0) |＜16, so Level_ β (0)=0,

So be for the coding result that adds in first frame the syntactic structure:

{

{

1；

01001；

0；

01010；

}

}

In decoding end, from a syntactic structure of the 0th frame, can extract:

Level_α(0)＝1，

Level_β(0)＝1，

Thereby decoding obtains: α (0) '=(0+12 * 9) rem (360)=108; The rem (360)=10 of β (0) '=(0+10).

As seen, because the delta_ α (0) of horizontal direction has been adopted first code level of expression coarse positioning, thereby the error that horizontal direction angle [alpha] (0) ' existences-2 spent that obtains of decoding end.

Second frame:

At coding side, the original value 110 before the horizontal direction angle [alpha] (0)=108 of its former frame rather than the renewal, and vertical direction angle beta (0)=10, then

delta_α(1)＝(115-108)rem360＝7，delta_β(1)＝(5-10)rem360＝-5；

Because | delta_ α (1) |＜16, so Level_ α (1)=0,

Because | delta_ β (1) |＜16, so Level_ β (1)=0,

So be for the coding result that adds in second frame the syntactic structure:

{

{

0；

00111；

0；

10101；

}

}

In decoding end, from a syntactic structure of second frame, can extract:

Level_α(1)＝0，

Level_β(1)＝0，

Thereby decoding obtains: the rem (360)=115 of α (1) '=(108+7); The rem (360)=5 of β (1) '=(10-5).

As seen, because when first frame is encoded, upgrade horizontal direction angle [alpha] (0)=108 rather than keep its original value 110, thereby after coarse positioning, utilize the fine positioning adjustment of second this frame of frame again, promptly obtained accurately horizontal direction angle [alpha] (1) ', and α (0) ' is existed the error concealments of-2 degree.

And, for ± 2 ^Q-1Angle outside the angular range, the bit number that coded system one needs is greater than Q, thereby difference hierarchical coding mode can reduce the required bandwidth of code stream than coded system one.

Alternatively, consider that the angle information after first code level is inaccurate, decoding end can think it transition result and abandon, and can occur other code words by the time the time, obtains angle information accurately again.

More than be detailed description to the various concrete decoding methods of the method that in code stream, embeds sound source bearing information in the present embodiment and sound source bearing information, below, the compression coding and decoding method and system to the embodiment of the invention is elaborated again.

Fig. 2 is the exemplary process diagram of compression coding and decoding method in the embodiment of the invention.As shown in Figure 2, the compression coding and decoding method in the present embodiment comprises:

Step 201 as compaction coding method, the audio frequency mono channel data are carried out compressed encoding to form code stream, and in code stream, add in the syntactic structure of each frame in the code stream information, also will be added in the syntactic structure of any frame of described code stream or multiframe behind the sound source bearing information coding.

Can adopt the arbitrary mode in the foregoing coded system one, two, three that sound source bearing information is encoded in this step.In this step, the sound source direction sign can also further be added, in a syntactic structure to represent whether sound source bearing information is arranged in this syntactic structure.

Step 202 as coding/decoding method, decoding obtains sound source bearing information in the syntactic structure of above-mentioned any frame or multiframe from code stream, and utilizing the code stream information of decoding and obtaining in the syntactic structure of each frame from this code stream, decoding obtains the audio frequency mono channel data of each frame.

Corresponding with step 201, can adopt the arbitrary mode in the foregoing decoding process one, two, three that sound source bearing information is decoded in this step.And if in a syntactic structure, further added the sound source direction sign in the step 201, then in this step after judging the sound source direction sign and representing in the syntactic structure sound source bearing information is arranged, carry out the operation of decoding in the syntactic structure to code stream again.

So far, this flow process finishes.

After this, because sound source bearing information has been added in the syntactic structure of audio frequency mono channel data code flow after encoding, thereby realized sound source bearing information is embedded in the code stream, so that sound source bearing information transmits with code stream.Thus, if above-mentioned flow process is applied in the monitoring scene, by front monitoring front-end execution in step 201, monitoring rear end execution in step 202, just need not between front monitoring front-end and monitoring rear end, to transmit or store the code stream of multichannel audio data, thereby avoided the code stream of front monitoring front-end output multichannel audio data and made the monitoring rear end be difficult to obtain the problem of accurate sound source bearing information, but also avoided the code stream transmission or the storage of multichannel audio data to take than large transmission bandwidth or storage space.

Need to prove, for the situation that also comprises the sound source direction sign in the syntactic structure, further, during the corresponding identical sound source bearing information of audio frequency mono channel data in continuous multiple frames, in order to reduce the sound source bearing information data volume that in code stream, embeds, with further saving code stream transmission bandwidth, step 201 in the above-mentioned flow process can be in a syntactic structure of first frame of above-mentioned continuous multiple frames, the sound source direction sign is set to represent to have in the syntactic structure effective value of sound source bearing information, and in a syntactic structure of first frame, add sound source bearing information behind the compressed encoding, and in a syntactic structure of follow-up all frames except that first frame, the sound source direction sign is set to represent the invalid value of no sound source direction information in the syntactic structure, and will not be added in the syntactic structure of follow-up all frames behind the above-mentioned sound source bearing information compressed encoding.

In the practical application, for code encoding/decoding mode one, two, coding angular resolution δ that can also pre-configured multiple value, step 201 can be chosen wantonly and wherein a kind of α and β be carried out compressed encoding.At this moment, for when step 202 is decoded, can know the coding angular resolution δ value of step 201 foundation, can further in a syntactic structure, add corresponding codes angular resolution mark in step 201, thus, step 202 identifies the coding angular resolution δ value of step 201 foundation according to coding angular resolution mark earlier, and then carries out subsequent treatment.

Fig. 3 is the exemplary block diagram of compression coding and decoding system in the embodiment of the invention.As shown in Figure 3, be example with the compression coding and decoding system applies in the present embodiment in supervisory system, this compression coding and decoding system comprises: scrambler 301 and demoder 302.

Wherein, scrambler 301 is arranged in the front monitoring front-end 310 of video monitoring system, and the microphone array in the front monitoring front-end 310 311, microphone array algorithm unit 312 are connected with scrambler 301 orders; 302 of demoders are arranged in the monitoring rear end 320 of video monitoring system, and link to each other respectively with control analysis module 322 with the audio playing unit 321 of monitoring in the rear end 320.

Scrambler 301 is as coding side, be used to receive the audio frequency mono channel data and the sound source bearing information of 312 outputs of microphone array algorithm unit, and the audio frequency mono channel data are carried out compressed encoding to form code stream, with when being added in the syntactic structure of each frame of code stream behind the code stream information coding, also will be added in the syntactic structure of any frame in the code stream or multiframe behind the sound source bearing information compressed encoding and output.

The code stream of scrambler 301 outputs can directly transfer to demoder 302 or the storage back obtains for demoder 302.

Demoder 302 is as decoding end, is used in the syntactic structure of above-mentioned any frame of the code stream of own coding device 301 always or multiframe, and decoding obtains sound source bearing information; And utilizing the code stream information of decoding and obtaining in the syntactic structure of each frame from this code stream, decoding obtains the audio frequency mono channel data of each frame from code stream; The sound source bearing information that obtains may be output to control analysis module 322, moves for the rotation of camera The Cloud Terrace in control analysis module 322 processing post analysis sound source movement locus, audio source tracking or the control supervisory system, and the audio frequency mono channel data that obtain then may be output to audio playing unit 321 and play.

Alternatively, scrambler 301 can be further used for adding the sound source direction sign in a syntactic structure, to represent whether sound source bearing information is arranged in this syntactic structure; Correspondingly, 302 of demoders are further used for after judging the sound source direction sign and representing in the syntactic structure sound source bearing information is arranged, and carrying out the processing that from a syntactic structure of code stream decoding obtains sound source bearing information again.

Further, for the situation that also comprises the sound source direction sign in the syntactic structure, and during the corresponding identical sound source bearing information of the audio frequency mono channel data in continuous multiple frames, in order to reduce the sound source bearing information data volume that in code stream, embeds, with further saving code stream transmission bandwidth, scrambler 301 can be in a syntactic structure of first frame of above-mentioned continuous multiple frames, the sound source direction sign is set to represent to have in the syntactic structure effective value of sound source bearing information, and in a syntactic structure of first frame, add sound source bearing information behind the compressed encoding, and in a syntactic structure of follow-up all frames except that first frame, the sound source direction sign is set to represent the invalid value of no sound source direction information in the syntactic structure, and will not be added in the syntactic structure of follow-up all frames behind the above-mentioned sound source bearing information compressed encoding.

In said system, scrambler 301 can be encoded to sound source bearing information based on the arbitrary mode in the foregoing coded system one, two, three.Correspondingly, scrambler 301 can be decoded to sound source bearing information based on the arbitrary mode in the foregoing decoding process one, two, three.

Need to prove, in the practical application, for code encoding/decoding mode one, two, coding angular resolution δ that can pre-configured multiple value in the scrambler 301, and scrambler 301 can be chosen wantonly and wherein a kind of α and β carried out compressed encoding.At this moment, just need scrambler 301 further in a syntactic structure, to add corresponding codes angular resolution mark, like this, demoder 302 identifies the coding angular resolution δ value of 301 foundations of scrambler earlier according to the coding angular resolution mark in the syntactic structure, and then carries out subsequent treatment.

As seen, audio coding and decoding system in the present embodiment has been added in the syntactic structure of audio frequency mono channel data code flow after sound source bearing information is encoded, thereby realized sound source bearing information is embedded in the code stream, so that sound source bearing information transmits with code stream.

Thus, just need not between front monitoring front-end and monitoring rear end, to transmit or store the code stream of multichannel audio data, thereby avoided the code stream of front monitoring front-end output multichannel audio data and made the monitoring rear end be difficult to obtain the problem of accurate sound source bearing information, but also avoided the code stream transmission or the storage of multichannel audio data to take than large transmission bandwidth or storage space.

The above is preferred embodiment of the present invention only, is not to be used to limit protection scope of the present invention.Within the spirit and principles in the present invention all, any modification of being done, be equal to and replace and improvement etc., all should be included within protection scope of the present invention.

Claims (11)

1. the coding method of a sound source bearing information, described sound source bearing information comprise the angle information on any direction of each audio data frame correspondence, it is characterized in that this coding method comprises:

C1, with the angle information of pairing each direction of present frame respectively with former frame in corresponding unidirectional angle information carry out calculus of differences, obtain the 3rd calculus of differences result of each direction;

C20, judge whether the 3rd calculus of differences result's of each direction value is positioned at outside the predetermined angular range, if, then order execution in step c21 and step c31; Otherwise, order execution in step c22 and step c32;

C21, to set this direction corresponding codes rank be first code level, utilize first order angle precision to quantize the 3rd calculus of differences result of this direction, obtain this direction the 4th calculus of differences result, and the 4th calculus of differences result of this direction is defined as result behind this orientation angle information coding;

C31, utilize counterparty in the 4th calculus of differences result, first order angle precision and the former frame to angle information, upgrade counterparty in the present frame to angle information, with compensation quantize error that the 4th calculus of differences produces as a result the time, and for encode the next frame counterparty to angle information the time use;

C22, to set this direction corresponding codes rank be second code level, utilize second level angle precision to quantize the 3rd calculus of differences result of this direction, obtain this direction the 5th calculus of differences result, and the 5th calculus of differences result of this direction is defined as result behind this orientation angle information coding;

C32, utilize counterparty in the 5th calculus of differences result, second level angle precision and the former frame to angle information, upgrade counterparty in the present frame to angle information, with compensation quantize error that the 5th calculus of differences produces as a result the time, and for encode the next frame counterparty to angle information the time use;

Wherein, second level angle precision is more than or equal to 1 and less than first order angle precision.

2. coding method as claimed in claim 1, it is characterized in that, described step c1 comprises: with the angle information of pairing each direction of present frame respectively with former frame in corresponding unidirectional angle information again 360 degree are got after subtracting each other surplusly, will get surplus result and be defined as the 3rd calculus of differences result.

3. coding method as claimed in claim 1 or 2 is characterized in that, described the 4th calculus of differences result have q bit, described the 5th calculus of differences result have Q, described predetermined angular range for ± (2 ^Q-1* θ), described first order angle precision is

Degree, P are for can be by 360 positive integers that divide exactly, and P satisfies: 2 ^Q-1＜P＜2 ^q,

θ is a second level angle precision;

And whether the value that step c20 is described to judge the 3rd calculus of differences result of each direction is positioned at outside the predetermined angular range and comprises:

Whether the difference of judging the 3rd calculus of differences result's the value of each direction and 360 degree and the 3rd calculus of differences result of each direction is all more than or equal to (2 ^Q-1* θ);

If the 3rd calculus of differences result's of either direction value and 360 degree are denied all more than or equal to (2 with the 3rd calculus of differences result's of this direction difference ^Q-1* θ), represent then whether the 3rd calculus of differences result's of this direction value is positioned at outside the predetermined angular range;

If the 3rd calculus of differences result's of the 3rd calculus of differences result's of either direction value or 360 degree and this direction difference is less than (2 ^Q-1* θ), represent then whether the 3rd calculus of differences result's of this direction value is positioned at outside the predetermined angular range.

4. coding method as claimed in claim 3 is characterized in that,

Described the 3rd calculus of differences result who utilizes first order angle precision to quantize this direction of step c21 comprises: the 3rd calculus of differences result quantities of this direction is turned to

The multiple of degree is defined as this multiple q bit the 4th calculus of differences result of this direction;

Described the 3rd calculus of differences result who utilizes second level angle precision to quantize this direction of step c22 comprises:

If the 3rd calculus of differences result's of either direction value is less than (2 ^Q-1* θ), then calculate the merchant of this direction the 3rd calculus of differences result and second level angle precision, and the span that will discuss be converted to ± 2 ^Q-1In so that its most significant digit is a sign bit, be the described merchant of sign bit Q bit the 5th calculus of differences result that to be defined as this direction most significant digit be sign bit then with most significant digit;

If the 3rd calculus of differences result of 360 degree and either direction is less than (2 ^Q-1* θ), the differences of then calculating this direction the 3rd calculus of differences result and 360 degree are divided by the merchant of second level angle precision, and the span that will discuss be converted to ± 2 ^Q-1In so that its most significant digit is a sign bit, be the described merchant of sign bit Q bit the 5th calculus of differences result that to be defined as this direction most significant digit be sign bit then with most significant digit.

5. coding method as claimed in claim 4 is characterized in that,

Described step c31 comprises: calculate first order angle precision and the 4th calculus of differences result's product, and with angle information sum corresponding in this product and the former frame to 360 spend get surplus, again this is got surplus result be updated to the present frame counterparty to angle information;

Described step c32 only carries out greater than 1 o'clock at second level angle precision, and comprise: the product that calculates second level angle precision and the 5th calculus of differences result, and angle information sum corresponding in this product and the former frame is got 360 degree surplus, again this is got surplus result be updated to the present frame counterparty to angle information.

6. coding method as claimed in claim 1 is characterized in that, this coding method further is added into the result behind each direction corresponding codes rank of present frame and each the orientation angle information coding in the syntactic structure of present frame.

7. the coding/decoding method of a sound source bearing information, described sound source bearing information comprises the angle information on any direction of each audio data frame correspondence, it is characterized in that the result behind each orientation angle information coding has the corresponding codes rank respectively, and this coding/decoding method comprises:

If corresponding first code level of the either direction in the present frame, this orientation angle information of then utilizing first order angle precision and in former frame, decoding and obtain, result behind this orientation angle information coding in the present frame is decoded, obtain the angle information of this direction in the present frame;

If corresponding second code level of the either direction in the present frame, this orientation angle information of then utilizing second level angle precision and in former frame, decoding and obtain, result behind this orientation angle information coding in the present frame is decoded, obtain the angle information of this direction in the present frame;

Wherein, second level angle precision is more than or equal to 1 and less than first order angle precision.

8. coding/decoding method as claimed in claim 7 is characterized in that, the result behind the angle information coding of the first code level correspondence is that the result after the angle information of q bit, the second code level correspondence is encoded is the Q bit, and first order angle precision is

Degree, P are for can be by 360 positive integers that divide exactly, and P satisfies: 2 ^Q-1＜P＜2 ^q,

θ is a second level angle precision;

Described this orientation angle information of utilizing first order angle precision and in former frame, decoding and obtain, result behind this orientation angle information coding in the present frame decoded comprise: the product that calculates the result after first order angle precision is encoded with q bit angle information, and this orientation angle information sum that the decoding of this product and former frame obtains is got surplus to 360 degree, will get the angle information that surplus result is defined as this direction in the present frame then;

Described this orientation angle information of utilizing second level angle precision and in former frame, decoding and obtain, result behind this orientation angle information coding in the present frame decoded comprise: the product that calculates the result after second level angle precision is encoded with Q bit angle information, and this orientation angle information sum that the decoding of this product and former frame obtains is got surplus to 360 degree, will get the angle information that surplus result is defined as this direction in the present frame then.

9. as claim 7 or 8 described coding/decoding methods, it is characterized in that the coding result of each direction corresponding codes rank of present frame and each orientation angle information all is carried in the syntactic structure of present frame; And this coding/decoding method further from a syntactic structure of present frame, extracts the coding result of each direction corresponding codes rank of present frame and each orientation angle information.

10. the decoding method of a sound source bearing information, described sound source bearing information comprise the angle information on any direction of each audio data frame correspondence, it is characterized in that this decoding method comprises the following steps of coding:

C1, with the angle information of pairing each direction of present frame respectively with former frame in corresponding unidirectional angle information carry out calculus of differences, obtain the 3rd calculus of differences result of each direction;

C20, judge whether the 3rd calculus of differences result's of each direction value is positioned at outside the predetermined angular range, if, then order execution in step c21 and step c31; Otherwise, order execution in step c22 and step c32;

C21, to set this direction corresponding codes rank be first code level, utilize first order angle precision to quantize the 3rd calculus of differences result of this direction, obtain this direction the 4th calculus of differences result, and the 4th calculus of differences result of this direction is defined as result behind this orientation angle information coding;

C31, utilize counterparty in the 4th calculus of differences result, first order angle precision and the former frame to angle information, upgrade counterparty in the present frame to angle information, with compensation quantize error that the 4th calculus of differences produces as a result the time, and for encode the next frame counterparty to angle information the time use;

C22, to set this direction corresponding codes rank be second code level, utilize second level angle precision to quantize the 3rd calculus of differences result of this direction, obtain this direction the 5th calculus of differences result, and the 5th calculus of differences result of this direction is defined as result behind this orientation angle information coding;

C32, utilize counterparty in the 5th calculus of differences result, second level angle precision and the former frame to angle information, upgrade counterparty in the present frame to angle information, with compensation quantize error that the 5th calculus of differences produces as a result the time, and for encode the next frame counterparty to angle information the time use;

This decoding method also comprises the following steps of decoding:

If corresponding first code level of the either direction in the present frame, this orientation angle information of then utilizing first order angle precision and in former frame, decoding and obtain, result behind this orientation angle information coding in the present frame is decoded, obtain the angle information of this direction in the present frame;

If corresponding second code level of the either direction in the present frame, this orientation angle information of then utilizing second level angle precision and in former frame, decoding and obtain, result behind this orientation angle information coding in the present frame is decoded, obtain the angle information of this direction in the present frame;

Wherein, second level angle precision is more than or equal to 1 and less than first order angle precision.

11. the coding/decoding system of a sound source bearing information, described sound source bearing information comprise the angle information on any direction of each audio data frame correspondence, and this coding/decoding system comprises continuous encoder, it is characterized in that,

Described scrambler is used for the unidirectional angle information that the angle information of pairing each direction of present frame is corresponding with former frame respectively and carries out calculus of differences, obtains the 3rd calculus of differences result of each direction; Whether the value of judging the 3rd calculus of differences result of each direction is positioned at outside the predetermined angular range, if, then setting this direction corresponding codes rank is first code level, utilize first order angle precision to quantize the 3rd calculus of differences result of this direction, obtain the 4th calculus of differences result of this direction, and the 4th calculus of differences result of this direction is defined as result behind this orientation angle information coding, utilize the 4th calculus of differences result then, first order angle precision, and in the former frame counterparty to angle information, upgrade counterparty in the present frame to angle information, quantize the error that the 4th calculus of differences produces as a result the time with compensation, and for coding next frame counterparty to angle information the time use; Otherwise, setting this direction corresponding codes rank is second code level, utilize second level angle precision to quantize the 3rd calculus of differences result of this direction, obtain the 5th calculus of differences result of this direction, and the 5th calculus of differences result of this direction is defined as result behind this orientation angle information coding, utilize the 5th calculus of differences result then, second level angle precision, and in the former frame counterparty to angle information, upgrade counterparty in the present frame to angle information, quantize the error that the 5th calculus of differences produces as a result the time with compensation, and for coding next frame counterparty to angle information the time use;

Described demoder, be used for when either direction correspondence first code level of present frame, this orientation angle information of utilizing first order angle precision and in former frame, decoding and obtain, result behind this orientation angle information coding in the present frame is decoded, obtain the angle information of this direction in the present frame; During corresponding second code level of either direction in present frame, this orientation angle information of utilizing second level angle precision and in former frame, decoding and obtain, result behind this orientation angle information coding in the present frame is decoded, obtain the angle information of this direction in the present frame;

Wherein, second level angle precision is more than or equal to 1 and less than first order angle precision.

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