CN101101755A - Audio frequency bit distribution and quantitative method and audio frequency coding device - Google Patents

Abstract

This method includes steps of: A, according to the parameter bit distributing and quantizing (BDQ) the last frame signal and also meeting the coding requirement, obtaining the initial value (IV) of the parameter for BDQ the current frame signal (CFS); B, using IV to BDQ repeatedly CFS until finding the parameter meeting the requirement of coding the current frame; BDQ the found parameter to obtain the audio specimen output. Besides, this invention also discloses a corresponding audio coding device. This method and device well uses the energy and frequency component relativity between two neighboring frame signals, therefore reduces the circular number and the calculating work.

Description

A kind of Bit Allocation in Discrete of audio coding and quantization method and audio coding apparatus

Technical field

The present invention relates to the audio coding technology, relate in particular to a kind of Bit Allocation in Discrete and quantization method and audio coding apparatus of audio coding.

Background technology

At present, audio coding apparatus is made up of four major parts usually, comprising: bank of filters, psychoacoustic model, Bit Allocation in Discrete quantize module and bitstream format module.Referring to Fig. 1, Fig. 1 shows the structural representation of prior art sound intermediate frequency code device.

Wherein, bank of filters is used to carry out the time-frequency domain mapping, and the sound signal of importing is mapped as frequency-region signal by time-domain signal, and the frequency-region signal that is shone upon is exported to Bit Allocation in Discrete quantification module.Wherein, frequency domain transform domain is in other words made a general reference the signal indication result that the various transform methods that adopt for the convenience of signal Processing obtain, these transform methods comprise: Fourier transform (FFT), revise discrete cosine transform (MDCT) and wavelet transformation (wavelet) etc.

Psychoacoustic model, be used for input signal is analyzed, determine according to the auditory model of people's ear which component can not encoded in the input signal, which component can be encoded etc. with lower precision, and generates control signal and export to Bit Allocation in Discrete and quantize module.

Bit Allocation in Discrete quantizes module, be used for according to the perceptual entropy PE information such as (perceptual entropy) when of making an uproar of covering from the control signal of psychoacoustic model, each scale factor band to the frequency-region signal of the bank of filters that received output carries out Bit Allocation in Discrete and quantification, and the audio samples after quantizing is exported to the bitstream format module.

The bitstream format module is used for the audio samples that Bit Allocation in Discrete quantizes module output is generated the code stream of compliant.

Wherein, Bit Allocation in Discrete quantizes that module is carried out Bit Allocation in Discrete to the scale factor band of every frame signal and when quantizing, in order to be issued to coding quality preferably to constant bit rate restriction, and the flatness etc. of considering overall code check, the quantification and the coding that need carry out repeatedly attempt deciding parameters such as suitable quantization step of each scale factor band and/or scale factor.That is: Bit Allocation in Discrete quantizes module each scale factor band is carried out Bit Allocation in Discrete and quantification, audio samples after quantizing is exported to the bitstream format module to be specially: at first will carry out Bit Allocation in Discrete and quantize parameters such as required quantization step and/or scale factor carrying out initial reset to current frame signal, use default value current frame signal to be carried out Bit Allocation in Discrete and quantization loop as initial value, find parameters such as the quantization step that satisfies the present frame coding requirement and/or scale factor, export to the bitstream format module utilizing this parameter that satisfies the present frame coding requirement to carry out the audio samples that Bit Allocation in Discrete and quantification obtain.

Wherein, Bit Allocation in Discrete and quantization loop can be two layers of circulation, also can be for other circulate, and existing is example with two layers of round-robin situation, and in two layers of circulation, interior circulation mainly is responsible for code check is controlled, and outer circulation mainly is responsible for distortion is controlled.In interior circulation, earlier frequency-region signal is quantized according to parameters such as scale factor and/or quantization steps, select code book, calculate the bit number that entropy coding needs, if the bit number that the bit number that entropy coding needs can be used less than system, then withdraw from interior circulation, enter outer circulation; Otherwise, adjust quantization step and/or scale factor and carry out circulation in next time.After the interior loop ends, the scale factor that outer circulation obtains according to inner loop is calculated the distortion of each scale factor band and is judged whether that all scale factor bands all meet the distortion requirement, if meet the demands, then loop ends, quantization step that utilization is met the demands and/or scale factor parameter carry out Bit Allocation in Discrete and quantize after audio samples output; Otherwise, adjust quantization step and/or scale factor and carry out interior next time circulation.

As seen, in the said process, when every frame signal being carried out Bit Allocation in Discrete and quantizing, employed quantization step and/or the scale factor of circulating is identical default initial value, be that the process of carrying out Bit Allocation in Discrete and quantification between every frame signal and the every frame signal all is independently, and in the practical application, very big correlativity arranged usually between adjacent two frame signals, owing to do not utilize this correlativity, cause the very big loop computation amount of existence in the cyclic process in the prior art.

Summary of the invention

In view of this, provide a kind of Bit Allocation in Discrete and quantization method of audio coding in the embodiment of the invention on the one hand, a kind of audio coding apparatus is provided on the other hand, so that reduce the loop computation amount.

The Bit Allocation in Discrete of the audio coding that is provided in the embodiment of the invention and quantization method comprise:

A, carry out Bit Allocation in Discrete and quantize the used parameter that satisfies coding requirement, obtain the initial value that current frame signal carries out Bit Allocation in Discrete and quantizes desired parameters according to the former frame signal;

B, utilize described initial value that current frame signal is carried out Bit Allocation in Discrete and quantization loop, find the parameter that satisfies the present frame coding requirement, will utilize the described parameter that satisfies the present frame coding requirement to carry out the audio samples output that Bit Allocation in Discrete and quantification obtain.

Wherein, described parameter comprises: quantization step and/or scale factor.

Wherein, described steps A is: the former frame signal is carried out Bit Allocation in Discrete and quantize the used parameter that meets the demands, carry out the initial value of Bit Allocation in Discrete and quantification desired parameters as current frame signal;

Perhaps be: the former frame signal is carried out Bit Allocation in Discrete and quantize the used parameter that meets the demands multiply by the parameter adjustment factor, obtain the initial value that current frame signal carries out Bit Allocation in Discrete and quantizes required quantization step.

Wherein, the described parameter adjustment factor comprises: ${\mathrm{\α}}_p=\frac{{\mathrm{PE}}_N}{{\mathrm{PE}}_{N-1}}$ And/or ${\mathrm{\α}}_b=\frac{B_N}{B_{N-1}},$ Wherein, PE _NBe the perceptual entropy of present frame, PE _N-1Be the perceptual entropy of former frame, B _NBe the available bit number of present frame, B _N-1Available bit number for former frame.

Preferably, further comprise before the steps A: whether the signal type of judging current frame signal is consistent with the signal type of former frame signal, if consistent, then carries out described steps A.

Preferably, this method further comprises: if the signal type of the signal type of current frame signal and former frame signal is inconsistent, then current frame signal is carried out Bit Allocation in Discrete and quantizes desired parameters carrying out initial reset, default value carried out Bit Allocation in Discrete as current frame signal and quantize the initial value of desired parameters, afterwards execution in step B.

The audio coding apparatus that is provided in the embodiment of the invention, comprise: psycho-acoustic module, Bit Allocation in Discrete quantize module, it is characterized in that, this device also comprises: initial parameter provides module, be used for carrying out Bit Allocation in Discrete and quantizing the used parameter that satisfies coding requirement according to the former frame signal, obtain the initial value that current frame signal carries out Bit Allocation in Discrete and quantizes desired parameters, the described initial value that obtains is offered Bit Allocation in Discrete quantize module;

Bit Allocation in Discrete quantizes module, utilize described initial value that current frame signal is carried out Bit Allocation in Discrete and quantization loop, find the parameter that satisfies the present frame coding requirement, to utilize the described parameter that satisfies the present frame coding requirement to carry out the audio samples output that Bit Allocation in Discrete and quantification obtain, and the described parameter that satisfies the present frame coding requirement is exported to initial parameter module is provided.

Preferably, this device further comprises: the signal type detection module, be used for the signal type of current frame signal is detected, and whether the signal type of judging current frame signal is consistent with the signal type of former frame signal, if consistent, then provide module to send parameter indication is provided to initial parameter; Otherwise, quantize module to Bit Allocation in Discrete and send the parameter initialization indication;

Described initial parameter provides mould to determine, provide indication according to described parameter from the signal type detection module, carry out and describedly carry out Bit Allocation in Discrete and quantize the used parameter that satisfies coding requirement according to the former frame signal, obtain the initial value that current frame signal carries out Bit Allocation in Discrete and quantizes desired parameters, the described initial value that obtains is offered the operation that Bit Allocation in Discrete quantizes module.

Described Bit Allocation in Discrete quantizes module further, also according to described parameter initialization indication from the signal type detection module, current frame signal is carried out Bit Allocation in Discrete and quantize desired parameters carrying out initial reset, utilize default value to carry out the described operation of current frame signal being carried out Bit Allocation in Discrete and quantization loop as initial value.

Wherein, described initial parameter provides module to comprise: memory module is used for the parameter that satisfies coding requirement that stored bits is distributed quantization modules output;

Parameter provides module, being used for obtaining the former frame signal from described memory module carries out Bit Allocation in Discrete and quantizes the used described parameter that satisfies coding requirement, the described parameter obtained carried out Bit Allocation in Discrete as current frame signal and quantize the initial value of desired parameters, described initial value is offered Bit Allocation in Discrete quantize module.

Perhaps, described initial parameter provides module to comprise: memory module, be used for stored bits and distribute the parameter that satisfies coding requirement of quantization modules output, and storage quantizes the available bit number of module from Bit Allocation in Discrete and/or from the perceptual entropy of psycho-acoustic module;

Parameter provides module, being used for obtaining the former frame signal from described memory module carries out Bit Allocation in Discrete and quantizes the used described parameter that satisfies coding requirement, and the perceptual entropy of the available bit number of former frame and present frame and/or former frame and present frame, the described parameter that utilization is obtained and described available bit number and/or perceptual entropy, obtain the initial value that current frame signal carries out Bit Allocation in Discrete and quantizes desired parameters, the described initial value that obtains is offered Bit Allocation in Discrete quantize module.

From such scheme as can be seen, carry out Bit Allocation in Discrete and quantize the used parameter that satisfies coding requirement according to the former frame signal in the embodiment of the invention, obtain the initial value that current frame signal carries out Bit Allocation in Discrete and quantizes desired parameters, and utilize described initial value that current frame signal is carried out Bit Allocation in Discrete and quantization loop, find the parameter that satisfies the present frame coding requirement, utilized the correlativity of energy and frequency component between adjacent two frame signals, utilize and carry out Bit Allocation in Discrete in the former frame and quantize used parameter, obtain the initial value that present frame carries out Bit Allocation in Discrete and quantizes desired parameters, make this initial value carry out Bit Allocation in Discrete and quantize the used parameter that satisfies coding requirement near present frame, thereby reduced the round-robin number of times, reduced the round-robin operand.

Further, obtaining before present frame carries out Bit Allocation in Discrete and quantize the initial value of desired parameters in the embodiment of the invention, increased the link that the signal type to present frame detects, and when the signal type of present frame is consistent with the signal type of former frame, carry out above-mentioned the utilization and carry out Bit Allocation in Discrete in the former frame and quantize used parameter, obtain the operation that present frame carries out Bit Allocation in Discrete and quantizes the initial value of desired parameters; Otherwise, can still handle according to prior art, promptly present frame is carried out Bit Allocation in Discrete and quantizes required parameter carrying out initial reset, utilize default value current frame signal to be carried out operations such as Bit Allocation in Discrete and quantization loop as initial value.But feasible variation of using the scheme adaptation signal in the embodiment of the invention, when signal is undergone mutation, the employing initial reset is handled, when signal is gradual, be beneficial to the correlativity of adjacent two frames, adopt in the former frame and carry out Bit Allocation in Discrete and quantize used parameter, obtain the initial value that present frame carries out Bit Allocation in Discrete and quantizes desired parameters, improved the efficient of Bit Allocation in Discrete and quantification.

Description of drawings

Fig. 1 is the structural representation of prior art sound intermediate frequency code device;

Fig. 2 is the Bit Allocation in Discrete of embodiment of the invention sound intermediate frequency coding and the process flow diagram of quantization method;

Fig. 3 is the structural representation of embodiment of the invention sound intermediate frequency code device.

Embodiment

Basic thought of the present invention is: carry out Bit Allocation in Discrete and quantize the used parameter that satisfies coding requirement according to the former frame signal, obtain the initial value that current frame signal carries out Bit Allocation in Discrete and quantizes desired parameters; Utilize described initial value that current frame signal is carried out Bit Allocation in Discrete and quantization loop, find the parameter that satisfies the present frame coding requirement, will utilize the described parameter that satisfies the present frame coding requirement to carry out the audio samples output that Bit Allocation in Discrete and quantification obtain.Wherein, parameter can comprise quantization step and/or scale factor etc.

Further, can at first judge the signal type of current frame signal, and when the signal type of judging this frame signal is consistent with the signal type of former frame signal, carry out Bit Allocation in Discrete and quantize the used parameter that satisfies coding requirement according to the former frame signal, obtain the initial value that current frame signal carries out Bit Allocation in Discrete and quantizes desired parameters; Otherwise, can still handle by prior art, promptly current frame signal is carried out Bit Allocation in Discrete and quantizes desired parameters carrying out initial reset, with default value as initial value.

For making the purpose, technical solutions and advantages of the present invention clearer, below in conjunction with embodiment and accompanying drawing, the present invention is described in more detail.

Referring to Fig. 2, Fig. 2 is the Bit Allocation in Discrete of embodiment of the invention sound intermediate frequency coding and the process flow diagram of quantization method.As shown in Figure 2, this flow process comprises the steps:

Step 201 detects the signal type of current frame signal.

Wherein, have in the method prior art that signal type is detected a variety of, as commonly used a kind of be the method that adopts perceptual entropy PE to judge.In the practical application, when using PE to judge, also need in conjunction with concrete sensor model, perhaps and the result of filter joint group etc. carry out analysis and judgement.

When utilizing perceptual entropy to judge, at first need to estimate the value of perceptual entropy, can adopt computing formula as the estimation of perceptual entropy $\mathrm{PE}=\frac{1}{N}\underset{f=f_l}{\overset{f=f_u}{\mathrm{\Σ}}}\max (0,{\log }_2\frac{\left|\sin \mathrm{gnal}\left(f\right)\right|}{\mathrm{threshold}\left(f\right)})---\left(1\right)$

Wherein, N is the number of frequency component, f _lAnd f _uBe the up-and-down boundary of frequency, as get 0Hz and 20000Hz.Signal (f) is the amplitude of frequency component f, and threshold (f) is for estimating the threshold value corresponding to frequency component f.As PE during, think that signal is a fast changed signal, otherwise be tempolabile signal greater than default certain threshold value.

In addition, signal type detection can also adopt any known transient state detection method etc., is not giving unnecessary details herein.

Step 202 judges whether the signal type of current frame signal is tempolabile signal and consistent with the signal type of former frame signal, if then execution in step 203; Otherwise, execution in step 204.

Wherein, if the signal type of current frame signal is a tempolabile signal, and the signal type of previous frame signal also is tempolabile signal, the signal type unanimity of then adjacent two frame signals, execution in step 203; If the signal type of current frame signal is a fast changed signal, and the signal type of previous frame signal is a tempolabile signal, the signal type of then adjacent two frame signals is inconsistent, execution in step 204; If adjacent two frame signals are fast changed signal, but because the characteristic of two frame fast changed signals is not necessarily approaching, so execution in step 204 still; If the previous frame signal is fast changed signal, and present frame is when being tempolabile signal, and then execution in step 204.And the like.

Step 203 is carried out Bit Allocation in Discrete and is quantized the used parameter that satisfies coding requirement according to the former frame signal, obtains the initial value that current frame signal carries out Bit Allocation in Discrete and quantizes desired parameters.Execution in step 205 afterwards.

Wherein, carry out Bit Allocation in Discrete and quantize the used parameter that satisfies coding requirement according to the former frame signal, obtain current frame signal carry out Bit Allocation in Discrete and quantize desired parameters initial value can for: the former frame signal is carried out Bit Allocation in Discrete and quantizes the used parameter that meets the demands, carry out Bit Allocation in Discrete and quantize the initial value of desired parameters as current frame signal.

Perhaps be: the former frame signal is carried out Bit Allocation in Discrete and quantize the used parameter that meets the demands multiply by the parameter adjustment factor, obtain the initial value that current frame signal carries out Bit Allocation in Discrete and quantizes required quantization step.Wherein, the parameter adjustment factor can comprise ${\mathrm{\α}}_p=\frac{{\mathrm{PE}}_N}{{\mathrm{PE}}_{N-1}}$ And/or ${\mathrm{\α}}_b=\frac{B_N}{B_{N-1}}$ Deng.Wherein, PE _NBe the perceptual entropy of present frame, PE _N-1Be the perceptual entropy of former frame, B _NBe the available bit number of present frame, B _N-1Available bit number for former frame.

Above-mentioned parameter can comprise quantization step and/or scale factor etc.

For example: suppose that above-mentioned parameter comprises quantization step, and hypothesis S _N-1For the former frame signal carries out Bit Allocation in Discrete and quantizes the used quantization step that meets the demands, then current frame signal carries out Bit Allocation in Discrete and quantizes the initial value S of required quantization step _NSCan be S _NS=S _N-1, perhaps also can be S _NS=α _pα _bS _N-1,

${\mathrm{\α}}_p=\frac{{\mathrm{PE}}_N}{{\mathrm{PE}}_{N-1}},$ ${\mathrm{\α}}_b=\frac{B_N}{B_{N-1}},$ Perhaps can also be S _NS=α S _N-1, wherein, $\mathrm{\α}={\mathrm{\α}}_p=\frac{{\mathrm{PE}}_N}{{\mathrm{PE}}_{N-1}},$ Perhaps $\mathrm{\α}={\mathrm{\α}}_b=\frac{B_N}{B_{N-1}}.$

Step 204 carries out Bit Allocation in Discrete and quantizes desired parameters carrying out initial reset to current frame signal, default value is carried out the initial value of Bit Allocation in Discrete and quantification desired parameters as current frame signal.Execution in step 205 afterwards.

In this step, implementation procedure can with prior art in consistent.

Step 205, utilize the initial value in step 203 or the step 204 that current frame signal is carried out Bit Allocation in Discrete and quantization loop, find the parameter that satisfies the present frame coding requirement, will utilize this parameter that satisfies the present frame coding requirement to carry out the audio samples output that Bit Allocation in Discrete and quantification obtain.

In this step, the process of current frame signal being carried out Bit Allocation in Discrete and quantization loop can be consistent with processing of the prior art.As: adopt two layers of circulation time, the interior circulation in two layers of circulation mainly is responsible for code check is controlled, and outer circulation mainly is responsible for distortion is controlled.In interior circulation, earlier frequency-region signal is quantized according to parameters such as scale factor and/or quantization steps, select code book, calculate the bit number that entropy coding needs, if the bit number that the bit number that entropy coding needs can be used less than system, then withdraw from interior circulation, enter outer circulation; Otherwise, adjust quantization step and/or scale factor and carry out circulation in next time.After the interior loop ends, the scale factor that outer circulation obtains according to inner loop is calculated the distortion of each scale factor band and is judged whether that all scale factor bands all meet the distortion requirement, if meet the demands, then loop ends, quantization step that utilization is met the demands and/or scale factor parameter carry out Bit Allocation in Discrete and quantize after audio samples output; Otherwise, adjust quantization step and/or scale factor and carry out interior next time circulation.

Comprise in the above-mentioned flow process that signal type to present frame detects and judges the step that adjacent two frame signal types are whether consistent.In the practical application, also can not comprise this step, and include only step 203 and step 205.

More than the Bit Allocation in Discrete and the quantization method of the audio coding in the embodiment of the invention are described in detail, again the audio coding apparatus in the embodiment of the invention is described in detail below.

Referring to Fig. 3, Fig. 3 is the structural representation of embodiment of the invention sound intermediate frequency code device.As shown in Figure 3, this device comprises: bank of filters, psychoacoustic model, Bit Allocation in Discrete quantification module, bitstream format module and initial parameter provide module.

Wherein, bank of filters is used to carry out the time-frequency domain mapping, and the sound signal of importing is mapped as frequency-region signal by time-domain signal, and the frequency-region signal that is shone upon is exported to Bit Allocation in Discrete quantification module.

Psychoacoustic model, be used for input signal is analyzed, determine according to the auditory model of people's ear which component can not encoded in the input signal, which component can be encoded etc. with lower precision, and generates control signal and send to Bit Allocation in Discrete and quantize module.

Initial parameter provides module, be used for carrying out Bit Allocation in Discrete and quantizing the used parameter that satisfies coding requirement according to the former frame signal, obtain the initial value that current frame signal carries out Bit Allocation in Discrete and quantizes desired parameters, the described initial value that obtains is offered Bit Allocation in Discrete quantize module.

Bit Allocation in Discrete quantizes module, be used for according to the perceptual entropy PE information such as (perceptual entropy) when of making an uproar of covering from the control signal of psychoacoustic model, each scale factor band to the frequency-region signal of the bank of filters that received output carries out Bit Allocation in Discrete and quantification, and the audio samples after quantizing is exported to the bitstream format module.Wherein, each scale factor band to the frequency-region signal of the bank of filters that received output carries out Bit Allocation in Discrete and quantification, audio samples after quantizing is exported to the bitstream format module to be specially: the initial value that utilizes initial parameter to provide module to provide carries out Bit Allocation in Discrete and quantization loop to the current frame signal that is received, find the parameter that satisfies the present frame coding requirement, export to the bitstream format module with utilizing the described parameter that satisfies the present frame coding requirement to carry out the audio samples that Bit Allocation in Discrete and quantification obtain, and the described parameter that satisfies the present frame coding requirement is exported to initial parameter module is provided, so that initial parameter provides module that it is stored, be used for the initial value that the next frame signal carries out Bit Allocation in Discrete and quantizes desired parameters is estimated.Wherein, consistent in round-robin process and the prior art.

The bitstream format module is used for the audio samples that Bit Allocation in Discrete quantizes module output is generated the code stream of compliant.

Wherein, initial parameter provides module to carry out Bit Allocation in Discrete and quantize the used parameter that satisfies coding requirement according to the former frame signal, obtain method that current frame signal carries out Bit Allocation in Discrete and quantize the initial value of desired parameters can have multiple, for example: can have two kinds that describe in the step 203 shown in Figure 2 at least.

During specific implementation, initial parameter provides module specifically to comprise: memory module and parameter provide module.During the first method described in adopting step 203 shown in Figure 2, memory module and parameter provide the concrete function of module and annexation as follows:

Memory module is used for the parameter that satisfies coding requirement that stored bits is distributed quantization modules output.

Parameter provides module, being used for obtaining the former frame signal from described memory module carries out Bit Allocation in Discrete and quantizes the used described parameter that satisfies coding requirement, the described parameter obtained carried out Bit Allocation in Discrete as current frame signal and quantize the initial value of desired parameters, described initial value is offered Bit Allocation in Discrete quantize module.

Wherein, memory module can all be stored the parameter that at every turn receives when parameter is stored, also can only store former frame and relevant parameter present frame, as: when receiving the relevant parameter of n frame, the parameter of discardable n-2 frame, and the like.

During the second method described in adopting step 203 shown in Figure 2, memory module and parameter provide the concrete function of module and annexation as follows:

Memory module is used for the parameter that satisfies coding requirement that stored bits is distributed quantization modules output, and storage quantizes the available bit number of module from Bit Allocation in Discrete and/or from the perceptual entropy of psycho-acoustic module.

Parameter provides module, being used for obtaining the former frame signal from described memory module carries out Bit Allocation in Discrete and quantizes the used described parameter that satisfies coding requirement, and the perceptual entropy of the available bit number of former frame and present frame and/or former frame and present frame, the described parameter that utilization is obtained and described available bit number and/or perceptual entropy, obtain the initial value that current frame signal carries out Bit Allocation in Discrete and quantizes desired parameters, the described initial value that obtains is offered Bit Allocation in Discrete quantize module.

Wherein, comprise as if the parameter adjustment factor ${\mathrm{\α}}_p=\frac{{\mathrm{PE}}_N}{{\mathrm{PE}}_{N-1}}$ With ${\mathrm{\α}}_b=\frac{B_N}{B_{N-1}}$ The time, when then former frame being encoded, psycho-acoustic module offers memory module with the perceptual entropy of former frame, the available bit number that Bit Allocation in Discrete quantizes the module former frame that system is definite offers memory module, Bit Allocation in Discrete quantizes module after Bit Allocation in Discrete quantizes, and the parameter that satisfies coding requirement of former frame is exported to memory module.When beginning present frame encoded, Bit Allocation in Discrete quantizes the available bit number of again that system is the definite present frame of module and exports to memory module, psycho-acoustic module offers memory module with the perceptual entropy of present frame, and memory module is stored the above-mentioned parameter that is received.

Parameter provides module to obtain the former frame signal from memory module to carry out Bit Allocation in Discrete and quantize the used described parameter that satisfies coding requirement, and the perceptual entropy of the available bit number of former frame and present frame and former frame and present frame, utilizes the parameters C of obtaining _{N-1 (i)}, 0＜i≤parameter sum, and available bit number and perceptual entropy are according to formula C _{NS (i)}=α _pα _bC _{N-1 (i)}, obtain the initial value C that current frame signal carries out Bit Allocation in Discrete and quantizes desired parameters _{NS (i)}, the described initial value that obtains is offered Bit Allocation in Discrete quantizes module.

If the parameter adjustment factor includes only ${\mathrm{\α}}_p=\frac{{\mathrm{PE}}_N}{{\mathrm{PE}}_{N-1}},$ When then former frame being encoded, the available bit number that Bit Allocation in Discrete quantizes the module former frame that system is definite offers memory module, and Bit Allocation in Discrete quantizes module after Bit Allocation in Discrete quantizes, and the parameter that satisfies coding requirement of former frame is exported to memory module.When beginning present frame encoded, psycho-acoustic module offers memory module with the perceptual entropy of present frame, and memory module is stored the above-mentioned parameter that is received.

Parameter provides module to obtain the former frame signal from memory module to carry out Bit Allocation in Discrete and quantize the used described parameter that satisfies coding requirement, and the perceptual entropy of former frame and present frame, utilizes the parameters C of obtaining _{N-1 (i)}And perceptual entropy, according to formula C _{NS (i)}=α _pC _{N-1 (i)}, obtain the initial value C that current frame signal carries out Bit Allocation in Discrete and quantizes desired parameters _{NS (i)}, the described initial value that obtains is offered Bit Allocation in Discrete quantizes module.

If the parameter adjustment factor includes only ${\mathrm{\α}}_b=\frac{B_N}{B_{N-1}},$ When then former frame being encoded, psycho-acoustic module offers memory module with the perceptual entropy of former frame, and Bit Allocation in Discrete quantizes module after Bit Allocation in Discrete quantizes, and the parameter that satisfies coding requirement of former frame is exported to memory module.When beginning present frame encoded, Bit Allocation in Discrete quantizes the available bit number of the present frame that module determines system again and exports to memory module, and memory module is stored the above-mentioned parameter that is received.

Parameter provides module to obtain the former frame signal from memory module to carry out Bit Allocation in Discrete and quantize the used described parameter that satisfies coding requirement, and the available bit number of former frame and present frame, utilizes the parameters C of obtaining _{N-1 (i)}And available bit number, according to formula C _{NS (i)}=α _bC _{N-1 (i)}, obtain the initial value C that current frame signal carries out Bit Allocation in Discrete and quantizes desired parameters _{NS (i)}, the described initial value that obtains is offered Bit Allocation in Discrete quantizes module.

Wherein, memory module is when storing parameter, the parameter that at every turn receives and available bit number and/or perceptual entropy all can be stored, also can only store former frame and relevant parameter present frame, as: when receiving the relevant parameter of n frame, the parameter of discardable n-2 frame, and the like.

Further, shown in the dotted line among Fig. 3, this device also can comprise: the signal type detection module, be used for the signal type of current frame signal is detected, and whether the signal type of judging current frame signal is consistent with the signal type of former frame signal, if consistent, then provide module to send parameter indication is provided to initial parameter; Otherwise, quantize module to Bit Allocation in Discrete and send the parameter initialization indication.

Then initial parameter provides module, provide indication according to described parameter from the signal type detection module, carry out and above-mentionedly carry out Bit Allocation in Discrete and quantize the used parameter that satisfies coding requirement according to the former frame signal, obtain the initial value that current frame signal carries out Bit Allocation in Discrete and quantizes desired parameters, the described initial value that obtains is offered the operation that Bit Allocation in Discrete quantizes module.

Bit Allocation in Discrete quantizes module further, also according to described parameter initialization indication from the signal type detection module, current frame signal is carried out Bit Allocation in Discrete and quantize desired parameters carrying out initial reset, utilize default value to carry out above-mentioned operations such as Bit Allocation in Discrete and quantization loop that current frame signal is carried out as initial value.

Above-described specific embodiment; purpose of the present invention, technical scheme and beneficial effect are further described; institute is understood that; the above only is preferred embodiment of the present invention; be 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 replacement, improvement etc., all should be included within protection scope of the present invention.

Claims (10)

1, a kind of Bit Allocation in Discrete of audio coding and quantization method is characterized in that, this method comprises:

A, carry out Bit Allocation in Discrete and quantize the used parameter that satisfies coding requirement, obtain the initial value that current frame signal carries out Bit Allocation in Discrete and quantizes desired parameters according to the former frame signal;

B, utilize described initial value that current frame signal is carried out Bit Allocation in Discrete and quantization loop, find the parameter that satisfies the present frame coding requirement, will utilize the described parameter that satisfies the present frame coding requirement to carry out the audio samples output that Bit Allocation in Discrete and quantification obtain.

2, the method for claim 1 is characterized in that, described parameter comprises: quantization step and/or scale factor.

3, the method for claim 1 is characterized in that, described steps A is: the former frame signal is carried out Bit Allocation in Discrete and quantize the used parameter that meets the demands, carry out the initial value of Bit Allocation in Discrete and quantification desired parameters as current frame signal;

Perhaps be: the former frame signal is carried out Bit Allocation in Discrete and quantize the used parameter that meets the demands multiply by the parameter adjustment factor, obtain the initial value that current frame signal carries out Bit Allocation in Discrete and quantizes required quantization step.

4, method as claimed in claim 3 is characterized in that, the described parameter adjustment factor comprises: ${\mathrm{\α}}_p=\frac{{\mathrm{PE}}_N}{{\mathrm{PE}}_{N-1}}$ And/or ${\mathrm{\α}}_b=\frac{B_N}{B_{N-1}},$ Wherein, PE _NBe the perceptual entropy of present frame, PE _N-1Be the perceptual entropy of former frame, B _NBe the available bit number of present frame, B _N-1Available bit number for former frame.

As each described method in the claim 1 to 4, it is characterized in that 5, further comprise before the steps A: whether the signal type of judging current frame signal is consistent with the signal type of former frame signal,, then carry out described steps A if consistent.

6, method as claimed in claim 5, it is characterized in that, this method further comprises: if the signal type of the signal type of current frame signal and former frame signal is inconsistent, then current frame signal is carried out Bit Allocation in Discrete and quantizes desired parameters carrying out initial reset, default value carried out Bit Allocation in Discrete as current frame signal and quantize the initial value of desired parameters, afterwards execution in step B.

7, a kind of audio coding apparatus, comprise: psycho-acoustic module, Bit Allocation in Discrete quantize module, it is characterized in that, this device also comprises: initial parameter provides module, be used for carrying out Bit Allocation in Discrete and quantizing the used parameter that satisfies coding requirement according to the former frame signal, obtain the initial value that current frame signal carries out Bit Allocation in Discrete and quantizes desired parameters, the described initial value that obtains is offered Bit Allocation in Discrete quantize module;

Bit Allocation in Discrete quantizes module, utilize described initial value that current frame signal is carried out Bit Allocation in Discrete and quantization loop, find the parameter that satisfies the present frame coding requirement, to utilize the described parameter that satisfies the present frame coding requirement to carry out the audio samples output that Bit Allocation in Discrete and quantification obtain, and the described parameter that satisfies the present frame coding requirement is exported to initial parameter module is provided.

8, device as claimed in claim 7, it is characterized in that, this device further comprises: the signal type detection module, be used for the signal type of current frame signal is detected, and whether the signal type of judging current frame signal is consistent with the signal type of former frame signal, if consistent, then provide module to send parameter indication is provided to initial parameter; Otherwise, quantize module to Bit Allocation in Discrete and send the parameter initialization indication;

Described initial parameter provides module, provide indication according to described parameter from the signal type detection module, carry out and describedly carry out Bit Allocation in Discrete and quantize the used parameter that satisfies coding requirement according to the former frame signal, obtain the initial value that current frame signal carries out Bit Allocation in Discrete and quantizes desired parameters, the described initial value that obtains is offered the operation that Bit Allocation in Discrete quantizes module.

Described Bit Allocation in Discrete quantizes module further, also according to described parameter initialization indication from the signal type detection module, current frame signal is carried out Bit Allocation in Discrete and quantize desired parameters carrying out initial reset, utilize default value to carry out the described operation of current frame signal being carried out Bit Allocation in Discrete and quantization loop as initial value.

9, as claim 7 or 8 described devices, it is characterized in that described initial parameter provides module to comprise: memory module is used for the parameter that satisfies coding requirement that stored bits is distributed quantization modules output;

Parameter provides module, being used for obtaining the former frame signal from described memory module carries out Bit Allocation in Discrete and quantizes the used described parameter that satisfies coding requirement, the described parameter obtained carried out Bit Allocation in Discrete as current frame signal and quantize the initial value of desired parameters, described initial value is offered Bit Allocation in Discrete quantize module.

10, as claim 7 or 8 described devices, it is characterized in that, described initial parameter provides module to comprise: memory module, be used for stored bits and distribute the parameter that satisfies coding requirement of quantization modules output, and storage quantizes the available bit number of module from Bit Allocation in Discrete and/or from the perceptual entropy of psycho-acoustic module;

Parameter provides module, being used for obtaining the former frame signal from described memory module carries out Bit Allocation in Discrete and quantizes the used described parameter that satisfies coding requirement, and the perceptual entropy of the available bit number of former frame and present frame and/or former frame and present frame, the described parameter that utilization is obtained and described available bit number and/or perceptual entropy, obtain the initial value that current frame signal carries out Bit Allocation in Discrete and quantizes desired parameters, the described initial value that obtains is offered Bit Allocation in Discrete quantize module.

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