CN101562015A - Audio-frequency processing method and device - Google Patents
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- G10L19/00—Speech or audio signals analysis-synthesis techniques for redundancy reduction, e.g. in vocoders; Coding or decoding of speech or audio signals, using source filter models or psychoacoustic analysis
- G10L19/02—Speech or audio signals analysis-synthesis techniques for redundancy reduction, e.g. in vocoders; Coding or decoding of speech or audio signals, using source filter models or psychoacoustic analysis using spectral analysis, e.g. transform vocoders or subband vocoders
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Abstract
The embodiment of the invention discloses an audio-frequency processing method and a device. The audio-frequency processing method comprises the following steps: determining an initial value of bit number distributed to each sub-band according to frequency domain envelope card values of sub-bands and the number of corrected discrete cosine transform MDCT coefficients contained in the sub-bands; matching the initial value of the bit number distributed to each sub-band with numerical values of a quantized bit distribution table; and determining the bit number distributed to each sub-band from the quantized bit distribution table. The embodiment of the invention correspondingly provides the audio-frequency processing device. The technical scheme provided by the embodiment of the invention can lower the complex degree of bit distribution.
Description
Technical field
The present invention relates to the audio signal processing technique field, be specifically related to a kind of audio-frequency processing method and device.
Background technology
Mainly adopted the perceptual coding method in the present audio signal processing technique, this coding method utilizes the masking effect of people's ear, omits unnecessary information, the compressed information amount.Here said audio frequency is a generalized concept, comprises signals such as voice, music.The masking effect of so-called people's ear, if be exactly that two sound are more approaching on time or frequency, so more weak sound will be hidden by stronger sound, at this moment people's ear can only be heard that stronger sound.According to the character of masking effect, can the arteface error signal in the quantizing process of audio coding, be no more than masking threshold as long as guarantee the equivalent noise or the distortion that quantize error band, the people just can't aware.
Bit Allocation in Discrete mechanism in the Audio Processing is exactly on the basis of psychoacoustic model, carries out the configuration of bit resource according to the size of masking threshold.The part that masking threshold is high can be distributed less bit number, and the part that masking threshold is low need be distributed more bit.By Bit Allocation in Discrete mechanism, can effectively utilize the bit resource, on the basis that does not influence the human auditory system effect, reduce encoder bit rate as much as possible, realize high efficiency coding.
Prior art proposes a kind of Bit distribution method, at TDAC (Time Domain AliasCancelling, the time domain aliasing is eliminated) when encoding, with (the Modified Discrete Cosine Transform of the MDCT in 0～7000Hz frequency band, the correction discrete cosine transform) coefficient has been divided into 18 subbands, carry out the perceptual importance ordering according to the size of the frequency domain envelope value of each subband, frequency domain envelope value big more (being that energy is big more), perceptual importance is important more, Bit Allocation in Discrete is carried out in ordering according to perceptual importance then, utilizes the binary search of oppositely filling out the water principle to realize Bit Allocation in Discrete.Detailed process is as follows:
1) by perceptual importance antithetical phrase tape sort, the perceptual importance of each subband is defined as
Wherein rms_indx (j) is the quantification energy corresponding codes index value of the frequency domain envelope value of subband j, has also represented the size of sub belt energy.
2) utilize the binary search of oppositely filling out the water principle to realize Bit Allocation in Discrete:
A, find " water level " λ by binary search
Opt, so that
Wherein, nbit (j) is a j subband allocation bit number, and nb_coef (j) is the number of the MDCT coefficient that comprises in j the subband, and nb_bits_max is the maximum bit number that can be used for the MDCT coefficient coding, and R is a quantization bit allocation table.
Concrete search procedure is: λ
OptThe hunting zone be λ
0=max (ip (j)), λ
1=min (ip (j))-4, searching times is 10 times.At first order
With it as λ
OptSubstitution formula 1, then, if
∑ nbit (j)＜nb_bits_max, then λ
0=λ, recycle carry out this step; If
∑ nbit (j)＞nb_bits_max, then λ
1=λ, recycle carry out this step.
B, find " water level " λ
OptAfter, according to the bit number of formula 1 each allocation of subbands of calculating.
3) if to all subbands according to step 2) allocation bit still has the bit resources left after finishing, and selects subband from high to low according to the perceptual importance of subband again, for the subband of selecting carries out Bit Allocation in Discrete again, determines the final bit number of this subband.
In research and practice process to prior art, the inventor finds that there is following problem in prior art:
When the prior art scheme is carried out Bit Allocation in Discrete by the binary search of oppositely filling out the water principle, need reach the optimum allocation of bit by the repeatedly search that repeatedly circulates, the complexity height.
Summary of the invention
The technical matters that the embodiment of the invention will solve provides a kind of audio-frequency processing method and device, can reduce the complexity of Bit Allocation in Discrete.
For solving the problems of the technologies described above, embodiment provided by the present invention is achieved through the following technical solutions:
The embodiment of the invention provides a kind of audio-frequency processing method, comprising: the bit number initial value of determining to distribute to each subband according to the correction discrete cosine transform MDCT coefficient number that comprises in the frequency domain envelope value of subband, the subband; Distribute to the bit number initial value of each subband and the numerical value in the quantization bit allocation table mates with described, from described quantization bit allocation table, determine to distribute to the bit number of each subband.
The embodiment of the invention provides a kind of apparatus for processing audio, comprising: the initial value determining unit, and the correction discrete cosine transform MDCT coefficient number that is used for comprising in the frequency domain envelope value, subband according to subband determines to distribute to the bit number initial value of each subband; Allocation units are used for distributing to the bit number initial value of each subband and the numerical value of quantization bit allocation table mates with described, determine to distribute to the bit number of each subband from described quantization bit allocation table.
Technique scheme as can be seen, after embodiment of the invention scheme is determined to distribute to the bit number initial value of each subband according to the envelope characteristic of subband itself, utilize known quantization bit allocation table, numerical value in the described bit number initial value of distributing to each subband and the known quantization bit allocation table is mated, thereby can reduce the complexity of Bit Allocation in Discrete greatly, and it is little to delay time, and occupying system resources is few.
Description of drawings
Fig. 1 is the Bit Allocation in Discrete process flow diagram in the embodiment of the invention one audio-frequency processing method;
Fig. 2 is at the Bit Allocation in Discrete process flow diagram of coding side in the embodiment of the invention two audio-frequency processing methods;
Fig. 3 is at the Bit Allocation in Discrete process flow diagram of decoding end in the embodiment of the invention three audio-frequency processing methods;
Fig. 4 is an embodiment of the invention apparatus for processing audio structural representation.
Embodiment
The embodiment of the invention provides a kind of audio-frequency processing method, is used for the complexity in coding or decode procedure reduction Bit Allocation in Discrete.
Seeing also Fig. 1, is the Bit Allocation in Discrete process flow diagram in the embodiment of the invention one audio-frequency processing method, comprising:
101, the subband with audio frequency carries out the perceptual importance ordering according to the frequency domain envelope value of subband;
102, determine to distribute to the bit number initial value of each subband according to the MDCT coefficient number that comprises in the frequency domain envelope value of subband, the subband;
103, the numerical value in the described bit number initial value of distributing to each subband and the known quantization bit allocation table is mated, from described quantization bit allocation table, determine to distribute to the bit number of each subband.
Need to prove, also can not carry out the perceptual importance ordering among the embodiment one.
In the process of coding or decoding, can adopt above-mentioned Bit distribution method, following content is to coding side and separately explanation of decoding end.In coding side and decoding end, all contained the quantization encoding table of bits that pre-sets.
Process at coding side in the embodiment of the invention Bit distribution method mainly comprises:
(1), each subband frequency domain envelope value is carried out pre-service;
The frequency domain envelope value of subband and the energy value of subband are corresponding.In this step, each subband frequency domain envelope value that coding obtains is carried out pre-service, according to increasing progressively of frequency band, the frequency domain envelope value is done successively decreasing of a small quantity, promptly make a decrement treatment, the absolute value of described decrement increases progressively by the increase of sub-band serial number.Pretreated purpose is that low frequency part has higher importance than HFS in order to ensure when low frequency sub-band and high-frequency sub-band have identical primary energy.Need to prove, also can not carry out pre-service.
(2), carry out the perceptual importance ordering according to pretreated frequency domain envelope value antithetical phrase band;
By sorting from big to small, the frequency domain envelope value is big more to pretreated frequency domain envelope value, and perceptual importance is important more.
(3), tentatively determine to distribute to the bit number of each subband;
According to the number of the MDCT coefficient that comprises in each subband frequency domain envelope value, the subband and the known bit number that can be used for the MDCT coefficient coding, tentatively determine to distribute to the bit number of each subband, and adjust the subband of perceptual important and the relative Bit Allocation in Discrete between the unessential subband of perception according to the perceptual weighting factor.
Need to prove, can not consider the known bit number that can be used for the MDCT coefficient coding, also can not consider weighting factor.
(4), the numerical value in the bit number of each subband that will tentatively determine and the known quantization encoding bit form is complementary, and finds the numerical value of the most approaching preliminary bit number of determining;
(5), if carry out also having remaining bit resource after the quantization bit coupling, according to the perceptual importance of subband, reallocate again, determine the final bit number of each subband.
After obtaining final bit allocation result by said process,, carry out quantization encoding to the result of each subband according to Bit Allocation in Discrete; To the subband MDCT coefficient information behind the quantization encoding be pressed importance input code flow from high to low through the frequency domain envelope value information input code flow of quantization encoding, transmit.
It is basic identical to carry out the processing procedure of the process of Bit Allocation in Discrete and coding side in decoding end in the embodiment of the invention method, mainly comprises:
(1), the frequency domain envelope value of decoding acquisition subband from code stream;
(2), the identical method of (1)～(5) step in the flow process of employing and front coding side is carried out Bit Allocation in Discrete;
(3), according to the result of Bit Allocation in Discrete, from code stream, read out the MDCT coefficient information of each subband accordingly.
Below further introduce embodiment of the invention scheme.
Seeing also Fig. 2, is at the Bit Allocation in Discrete process flow diagram of coding side in the embodiment of the invention two audio-frequency processing methods.
At coding side, the one group of M point MDCT coefficient that obtains by the coding flow process is divided into N subband band (i), and the number of the MDCT coefficient that comprises in each subband is nb_coef (i),
The frequency domain envelope value of each subband is log_rms (i), and the energy value of frequency domain envelope value and this subband is corresponding, and the bit number that coding side can be used for the MDCT coefficient quantization is nb_bits_max.
Comprise among Fig. 2:
201, each the subband frequency domain envelope value that obtains behind the coding is carried out pre-service;
Frequency domain envelope value to each subband of obtaining behind the coding is carried out pre-service:
Log_rms (i)=log_rms (i)-ε, wherein ε is relevant with an i small quantity that increases progressively, and is made as ε=i in the present embodiment
2* 0.002, it should be noted that the ε value just illustrates but is not limited to this herein.
Pretreated purpose is that low frequency part has higher importance than HFS in order to ensure when low frequency sub-band and high-frequency sub-band have identical primary energy.Pre-service is to illustrate so that the frequency domain envelope value is done successively decreasing of a trace in the embodiment of the invention, also can guarantee that when low frequency sub-band and high-frequency sub-band had identical primary energy, low frequency part had higher importance than HFS by other modes.
Need to prove, also can not carry out pre-service.
202, carry out the perceptual importance ordering according to pretreated frequency domain envelope value antithetical phrase band;
According to pretreated frequency domain envelope value, bring line ordering into by order antithetical phrase from big to small, each subband corresponding sequencing result is ord[i], the frequency domain envelope value is big more, corresponding ord[i] more little, perceptual importance is important more.
If do not carry out pre-service,, bring line ordering into by order antithetical phrase from big to small then directly according to the frequency domain envelope value.
203, tentatively determine to distribute to the bit number of each subband;
At first, the bit number that each MDCT coefficient should distribute in theory in the subband is directly determined by the frequency domain envelope value of this subband, the bit number that each subband should distribute in theory is: bit_rms (i)=over_rmsg * log_rms (i) * nb_coef (i), wherein over_rmsg is the perceptual weighting factor, the big more then Bit Allocation in Discrete of this value scheme rushes into extremes more, be that the important more bit number that subband distributed of perceptual importance is many relatively more, the bit number of the unessential more allocation of subbands of perceptual importance is few relatively more; The more little then Bit Allocation in Discrete of this value scheme is tending towards on average more, and when this value equaled extreme case 0, perceptual importance was that the bit number that distributed of important and unessential subband is identical, and promptly whole Bit Allocation in Discrete scheme is not considered perceptual importance, has carried out mean allocation.In the present embodiment be the example explanation but be not limited to this with over_remsg=0.75.Need to prove that also can not consider the perceptual weighting factor this moment.
Secondly, consider practical situations, calculate the actual assignable bit number of each subband, as the bit number of tentatively determining to distribute to each subband:
Considered the bit number of the actual MDCT of can be used for coefficient quantization and the bit number that should distribute in theory in this formula, therefore more practical.Observe this formula, can find ∑ bat_opt (i)=nb_bits_max, both made full use of assignable bit resource, considered the different perceptual importance of each subband again, and can to utilize perceptual weighting factor over_rmsg be importantly to adjust with the relative Bit Allocation in Discrete of unessential subband to perceptual importance, guarantee after the important subband of perceptual importance has distributed enough bit resources, no longer to take the more bits resource, and the slightly unessential subband of perceptual importance also can be assigned to certain bit resource, thereby better solves the Bit Allocation in Discrete that exists in prior art problem improperly.Need to prove, also can not consider the perceptual weighting factor when calculating actual assignable bit number.In addition, also can directly adopt bit number that each subband should distribute in theory bit number as preliminary each subband of determining.
The bit number of each subband that calculates at this moment, is a real number.
204, the bit number of each subband that will tentatively determine and quantization encoding Bit Allocation in Discrete table mate, and determine the Bit Allocation in Discrete number of each subband;
At coding side, set in advance fixing quantization encoding table of bits, a promptly known possible Bit Allocation in Discrete set R={q_bit
0, q_bit
1, Λ }, q_bit wherein
0＜q_bit
1＜Λ.So, behind the bit number by tentatively definite each subband of preceding step, search and preliminary definite immediate numerical value of bit number in this set are with the Bit Allocation in Discrete number of this numerical value as the subband of determining.
Carry out after the Bit Allocation in Discrete table coupling, the bit number of each allocation of subbands is: bat_bit (i)=q_bit
k, wherein
The bit resource allocatedbits=∑ bat_bit (i) that has then consumed, and satisfy allocatedbits≤nb_bits_max.
If 205 also have the bit resources left, remaining bit resource is reallocated by the perceptual importance of subband, determine the final Bit Allocation in Discrete number of subband.
As carried out also having the bit resources left after the Bit Allocation in Discrete table coupling, and then remaining bit resource to be reallocated by the perceptual importance of subband, the process of step 205 is as follows:
If allocatedbits＜nb_bits_max and 0≤i＜N then repeats following steps:
2051, according to perceptual importance select progressively subband band (ord[i]) from important to unessential;
2052, the bit number that distributed of known this subband is bat_bit (ord[i])=q_bit
kIf, then increase the bit number of its distribution, consider known possible Bit Allocation in Discrete set R, the bit number of this allocation of subbands should be q_bit
K+1, and meet the following conditions: if allocatedbits+q_bits
K+1-q_bits
k≤ nb_bits_max, then bat_bit (ord[i])=q_bit
K+1, allocatedbits=allocatedbits+q_bits
K+1-q_bits
k, otherwise bat_bit (ord[i])=q_bit
k
After obtaining final bit allocation result bat_bit (i) by said process, one group of MDCT coefficient to each subband carries out quantization encoding, frequency domain envelope value information behind the quantization encoding is added encoding code stream, the quantization encoding information of MDCT coefficient is added encoding code stream according to importance order from high to low.
What Fig. 2 mainly described is the method for coding side, and for decoding end, its decoded Bit Allocation in Discrete also is identical principle, and the processing procedure of process and coding side is similar.
See also Fig. 3, be in the embodiment of the invention three audio-frequency processing methods at the Bit Allocation in Discrete process flow diagram of decoding end, comprising:
301, each the subband frequency domain envelope value that obtains after the decoding is carried out pre-service;
Read frequency domain envelope value information from the code stream that receives, decoding obtains one group of frequency domain envelope value log_rms (i), and the bit number of the known MDCT of can be used for coefficient quantization is nb_bits_max.
Frequency domain envelope value to each subband of obtaining after the decoding is carried out pre-service: log_rms (i)=log_rms (i)-ε, and wherein ε is relevant with an i small quantity that increases progressively, and is made as ε=i in the present embodiment
2* 0.002, it should be noted that the ε value just illustrates but is not limited to this herein.
Pretreated purpose is that low frequency part has higher importance than HFS in order to ensure when low frequency sub-band and high-frequency sub-band have identical primary energy.Pre-service is to illustrate so that the frequency domain envelope value is done successively decreasing of a trace in the embodiment of the invention, also can guarantee that when low frequency sub-band and high-frequency sub-band had identical primary energy, low frequency part had higher importance than HFS by other modes.
Need to prove, also can not carry out pre-service.
302, carry out the perceptual importance ordering according to pretreated frequency domain envelope value antithetical phrase band;
According to pretreated frequency domain envelope value, bring line ordering into by order antithetical phrase from big to small, each subband corresponding sequencing result is ord[i], the frequency domain envelope value is big more, corresponding ord[i] more little, perceptual importance is important more.
If do not carry out pre-service,, bring line ordering into by order antithetical phrase from big to small then directly according to the frequency domain envelope value.
303, tentatively determine to distribute to the bit number of each subband;
At first, the bit number that each MDCT coefficient should distribute in theory in the subband is directly determined by the frequency domain envelope value of this subband, the bit number that each subband should distribute in theory is: bit_rms (i)=over_rmsg * log_rms (i) * nb_coef (i), wherein over_rmsg is the perceptual weighting factor, the big more then Bit Allocation in Discrete of this value scheme rushes into extremes more, be that the important more bit number that subband distributed of perceptual importance is many relatively more, the bit number of the unessential more allocation of subbands of perceptual importance is few relatively more; The more little then Bit Allocation in Discrete of this value scheme is tending towards on average more, and when this value equaled extreme case 0, perceptual importance was that the bit number that distributed of important and unessential subband is identical, and promptly whole Bit Allocation in Discrete scheme is not considered perceptual importance, has carried out mean allocation.In the present embodiment be the example explanation but be not limited to this with over_remsg=0.75.Need to prove that also can not consider the perceptual weighting factor this moment.
Secondly, consider practical situations, calculate the actual assignable bit number of each subband, as the bit number of tentatively determining to distribute to each subband:
Considered the bit number of the actual MDCT of can be used for coefficient quantization and the bit number that should distribute in theory in this formula, therefore more practical.Observe this formula, can find ∑ bat_opt (i)=nb_bits_max, both made full use of assignable bit resource, considered the different perceptual importance of each subband again, and can to utilize perceptual weighting factor over_rmsg be importantly to adjust with the relative Bit Allocation in Discrete of unessential subband to perceptual importance, guarantee after the important subband of perceptual importance has distributed enough bit resources, no longer to take the more bits resource, and the slightly unessential subband of perceptual importance also can be assigned to certain bit resource, thereby better solves the Bit Allocation in Discrete that exists in prior art problem improperly.Need to prove, also can not consider the perceptual weighting factor when calculating actual assignable bit number.In addition, also can directly adopt bit number that each subband should distribute in theory bit number as preliminary each subband of determining.
The bit number of each subband that calculates at this moment, is a real number.
304, the bit number of each subband that will tentatively determine and quantization encoding Bit Allocation in Discrete table mate, and determine the Bit Allocation in Discrete number of each subband;
In decoding end, with the same, set in advance fixing quantization encoding table of bits, a promptly known possible Bit Allocation in Discrete set R={q_bit at coding side
0, q_bit
1, Λ }, q_bit wherein
0＜q_bit
1＜Λ.So, behind the bit number by tentatively definite each subband of preceding step, search and preliminary definite immediate numerical value of bit number in this set are with the Bit Allocation in Discrete number of this numerical value as the subband of determining.
Carry out after the Bit Allocation in Discrete table coupling, the bit number of each allocation of subbands is: bat_bit (i)=q_bit
k, wherein
The bit resource allocatedbits=∑ bat_bit (i) that has then consumed, and satisfy allocatedbits≤nb_bits_max.
If 305 also have the bit resources left, remaining bit resource is reallocated by the perceptual importance of subband, determine the final Bit Allocation in Discrete number of subband.
As carried out also having the bit resources left after the Bit Allocation in Discrete table coupling, and then remaining bit resource to be reallocated by the perceptual importance of subband, the process of step 305 is as follows:
If allocatedbits＜nb_bits_max and 0≤i＜N then repeats following steps:
3051, according to perceptual importance select progressively subband band (ord[i]) from important to unessential;
3052, the bit number that distributed of known this subband is bat_bit (ord[i])=q_bit
kIf, then increase the bit number of its distribution, consider known possible Bit Allocation in Discrete set R, the bit number of this allocation of subbands should be q_bit
K+1, and meet the following conditions: if allocatedbits+q_bits
K+1-q_bits
k≤ nb_bits_max, then bat_bit (ord[i])=q_bit
K+1, allocatedbits=allocatedbits+q_bits
K+1-q_bits
k, otherwise bat_bit (ord[i])=q_bit
k
Behind the bit number that obtains each final allocation of subbands, according to the bit number bat_bit (i) of each the final allocation of subbands that obtains and the perceptual importance ordering ord[i of subband], read the result of the MDCT coefficient quantization coding of each subband successively from the code stream that receives, it is decoded obtains the MDCT coefficient.
Foregoing describes embodiment of the invention audio-frequency processing method in detail, and corresponding, the embodiment of the invention provides a kind of apparatus for processing audio.
Seeing also Fig. 4, is embodiment of the invention apparatus for processing audio structural representation.
As shown in Figure 4, apparatus for processing audio comprises: initial value determining unit 402, allocation units 403.
Initial value determining unit 402, the MDCT coefficient number that is used for comprising in the frequency domain envelope value, subband according to subband determines to distribute to the bit number initial value of each subband.
Apparatus for processing audio further comprises sequencing unit 401, is used for subband is carried out the perceptual importance ordering according to the frequency domain envelope value of subband.
Apparatus for processing audio further comprises: pretreatment unit 404.
The initial value determining unit 402 of apparatus for processing audio can be to comprise: first computing unit 4021, first processing unit 4022.
The initial value determining unit 402 of apparatus for processing audio can be to comprise: second computing unit 4023, second processing unit 4024.
Weighting factor adjustment unit 4025 is used for distributing to by the weighting factor adjustment bit number initial value of each subband.Weighting factor adjustment unit 4025 specifically can be distributed to the bit number initial value of each subband by the weighting factor adjustment in the computation process of the first above-mentioned computing unit 4021 or second computing unit 4023.
Described allocation units 403 comprise: search unit 4031, apportioning cost determining unit 4032.
Apportioning cost determining unit 4032 is used for the numerical value that search obtains is defined as distributing to the bit number of subband.
Apparatus for processing audio further comprises: adjustment unit 405.
Described apparatus for processing audio can be arranged on scrambler and carry out Bit Allocation in Discrete, also can be arranged on to carry out Bit Allocation in Discrete in the demoder.
In sum, after embodiment of the invention scheme is determined to distribute to the bit number initial value of each subband according to the envelope characteristic of subband itself, utilize known quantization bit allocation table, numerical value in the described bit number initial value of distributing to each subband and the known quantization bit allocation table is mated, thereby can reduce the complexity of Bit Allocation in Discrete greatly, and it is little to delay time, and occupying system resources is few.
Further, MDCT coefficient number, bit number that can be used for distributing that comprises in the frequency domain envelope value, subband of subband and the weighting factor that is used to adjust have been taken all factors into consideration when determining to distribute to the bit number initial value of each subband in the embodiment of the invention scheme, both made full use of assignable bit resource, considered the different perceptual importance of each subband again, utilizing weighting factor is importantly to adjust with the relative Bit Allocation in Discrete of unessential subband to perceptual importance, thereby better solves the Bit Allocation in Discrete that exists in prior art problem improperly.
Further, the frequency domain envelope value to subband in the embodiment of the invention scheme is carried out pre-service, guarantees that when low frequency sub-band and high-frequency sub-band had identical primary energy, low frequency part had higher importance than HFS.
In addition, the software of realizing the embodiment of the invention can be stored in the computer-readable recording medium, this software may further comprise the steps when carrying out: the bit number initial value of determining to distribute to each subband according to the correction discrete cosine transform MDCT coefficient number that comprises in the frequency domain envelope value of subband, the subband; Distribute to the bit number initial value of each subband and the numerical value in the quantization bit allocation table mates with described, from described quantization bit allocation table, determine to distribute to the bit number of each subband.Described storage medium can be Rom/Ram, disk, CD etc.
More than a kind of audio-frequency processing method and device that the embodiment of the invention provided are described in detail, for one of ordinary skill in the art, thought according to the embodiment of the invention, part in specific embodiments and applications all can change, in sum, this description should not be construed as limitation of the present invention.
Claims (19)
1, a kind of audio-frequency processing method is characterized in that, comprising:
Determine to distribute to the bit number initial value of each subband according to the correction discrete cosine transform MDCT coefficient number that comprises in the frequency domain envelope value of subband, the subband;
Distribute to the bit number initial value of each subband and the numerical value in the quantization bit allocation table mates with described, from described quantization bit allocation table, determine to distribute to the bit number of each subband.
2, audio-frequency processing method according to claim 1 is characterized in that, further comprises before the described bit number initial value of determining to distribute to each subband:
Subband is carried out the perceptual importance ordering according to the frequency domain envelope value of subband.
3, audio-frequency processing method according to claim 2 is characterized in that, described subband is carried out further comprising before the perceptual importance ordering according to the frequency domain envelope value of subband:
The frequency domain envelope value of subband is made a decrement treatment, and the absolute value of described decrement increases progressively by the increase of sub-band serial number.
4, audio-frequency processing method according to claim 2 is characterized in that, the correction discrete cosine transform MDCT coefficient number that comprises in described frequency domain envelope value according to subband, the subband determines that the bit number initial value of distributing to each subband is specially:
Determine the bit number theoretical value according to the correction discrete cosine transform MDCT coefficient number that comprises in the frequency domain envelope value of subband, the subband, with described bit number theoretical value as the bit number initial value of distributing to each subband.
5, audio-frequency processing method according to claim 2 is characterized in that, the correction discrete cosine transform MDCT coefficient number that comprises in described frequency domain envelope value according to subband, the subband determines that the bit number initial value of distributing to each subband is specially:
Determine the bit number theoretical value according to the MDCT coefficient number that comprises in the frequency domain envelope value of subband, the subband, determine the bit number actual value according to described bit number theoretical value and the bit number that can be used for distributing, with described bit number actual value as the bit number initial value of distributing to each subband.
6, according to claim 4 or 5 described audio-frequency processing methods, it is characterized in that:
Further comprise the bit number initial value of distributing to each subband by the weighting factor adjustment.
7, audio-frequency processing method according to claim 1, it is characterized in that, describedly will distribute to the bit number initial value of each subband and the numerical value in the quantization bit allocation table mates, determine that from described quantization bit allocation table the bit number of distributing to each subband is specially:
Search and the described immediate numerical value of bit number initial value of distributing to each subband from described quantization bit allocation table, the numerical value that search is obtained is defined as distributing to the bit number of subband.
8, audio-frequency processing method according to claim 2 is characterized in that, further comprises after determining to distribute to the bit number of each subband:
If find to also have the bit resources left, then select subband from high to low by perceptual importance;
For the subband of described selection carries out the bit reallocation, determine the final bit number of each subband.
9, audio-frequency processing method according to claim 8 is characterized in that, and is described for the subband of selecting carries out the bit reallocation, determines that the final bit number of each subband is specially:
In described quantization bit allocation table, for the subband of described selection is searched for the bit number of distributing to this subband again, described search is again distributed to the bit number of this subband and the difference of having distributed to the bit number of this subband and is less than or equal to the bit number that can be used for distributing and the difference of allocation bit number.
10, audio-frequency processing method according to claim 1 is characterized in that:
The frequency domain envelope value of described subband obtains by cataloged procedure; Perhaps,
The frequency domain envelope value of described subband obtains by decode procedure.
11, a kind of apparatus for processing audio is characterized in that, comprising:
The initial value determining unit, the correction discrete cosine transform MDCT coefficient number that is used for comprising in the frequency domain envelope value, subband according to subband determines to distribute to the bit number initial value of each subband;
Allocation units are used for distributing to the bit number initial value of each subband and the numerical value of quantization bit allocation table mates with described, determine to distribute to the bit number of each subband from described quantization bit allocation table.
12, apparatus for processing audio according to claim 11 is characterized in that, further comprises:
Sequencing unit is used for subband is carried out the perceptual importance ordering according to the frequency domain envelope value of subband.
13, apparatus for processing audio according to claim 12 is characterized in that, further comprises:
Pretreatment unit is used for the frequency domain envelope value of subband is made a decrement treatment, and the absolute value of described decrement increases progressively by the increase of sub-band serial number;
Described sequencing unit obtains the frequency domain envelope value of subband from described pretreatment unit.
14, apparatus for processing audio according to claim 11 is characterized in that, described initialization value determining unit comprises:
First computing unit is determined the bit number theoretical value according to the correction discrete cosine transform MDCT coefficient number that comprises in the frequency domain envelope value of subband, the subband;
First processing unit is used for described bit number theoretical value as the bit number initial value of distributing to each subband.
15, apparatus for processing audio according to claim 11 is characterized in that, described initial value determining unit comprises:
Second computing unit, the MDCT coefficient number that is used for comprising in the frequency domain envelope value, subband according to subband is determined the bit number theoretical value, determines the bit number actual value according to described bit number theoretical value and the bit number that can be used for distributing;
Second processing unit is used for described bit number actual value as the bit number initial value of distributing to each subband.
According to claim 14 or 15 described apparatus for processing audio, it is characterized in that 16, described initial value determining unit further comprises:
The weighting factor adjustment unit is used for distributing to by the weighting factor adjustment bit number initial value of each subband.
17, apparatus for processing audio according to claim 11 is characterized in that, described allocation units comprise:
Search unit is used for from described quantization bit allocation table search and the described immediate numerical value of bit number initial value of distributing to each subband;
The apportioning cost determining unit is used for the numerical value that search obtains is defined as distributing to the bit number of subband.
18, apparatus for processing audio according to claim 12 is characterized in that, further comprises:
Adjustment unit when being used for find also having the bit resources left, is selected subband from high to low by perceptual importance from described sequencing unit, for the subband of described selection carries out the bit reallocation, determine the final bit number of each subband.
19, apparatus for processing audio according to claim 11 is characterized in that:
Described apparatus for processing audio is arranged in scrambler or the demoder.
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| CNA2008100875949A CN101562015A (en) | 2008-04-18 | 2008-04-18 | Audio-frequency processing method and device |
| PCT/CN2009/070712 WO2009127133A1 (en) | 2008-04-18 | 2009-03-10 | An audio frequency processing method and device |
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| WO2011063694A1 (en) * | 2009-11-27 | 2011-06-03 | 中兴通讯股份有限公司 | Hierarchical audio coding, decoding method and system |
| US8145695B2 (en) | 2009-06-24 | 2012-03-27 | Huawei Technologies Co., Ltd. | Signal processing method and data processing method and apparatus |
| CN102081926B (en) * | 2009-11-27 | 2013-06-05 | 中兴通讯股份有限公司 | Method and system for encoding and decoding lattice vector quantization audio |
| CN104681028A (en) * | 2013-12-02 | 2015-06-03 | 华为技术有限公司 | Encoding method and encoding device |
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| WO2022156556A1 (en) * | 2021-01-21 | 2022-07-28 | 华为技术有限公司 | Bit allocation method and apparatus for audio object |
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| JP3134455B2 (en) * | 1992-01-29 | 2001-02-13 | ソニー株式会社 | High efficiency coding apparatus and method |
| CN100474780C (en) * | 2002-08-21 | 2009-04-01 | 广州广晟数码技术有限公司 | Decoding method for decoding and re-establishing multiple audio track audio signal from audio data stream after coding |
| KR100477701B1 (en) * | 2002-11-07 | 2005-03-18 | 삼성전자주식회사 | An MPEG audio encoding method and an MPEG audio encoding device |
| JP4273062B2 (en) * | 2004-09-09 | 2009-06-03 | ティーオーエー株式会社 | Encoding method, encoding apparatus, decoding method, and decoding apparatus |
| SG136836A1 (en) * | 2006-04-28 | 2007-11-29 | St Microelectronics Asia | Adaptive rate control algorithm for low complexity aac encoding |
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| CN105637582B (en) * | 2013-10-17 | 2019-12-31 | 株式会社索思未来 | Audio encoding device and audio decoding device |
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