CN1950686A - Encoding device, decoding device, and method thereof - Google Patents

Abstract

There is disclosed an encoding device capable of appropriately adjusting the dynamic range of spectrum inserted according to the technique for replacing a spectrum of a certain band with a spectrum of another band. The device includes a spectrum deformation unit (112) which deforms a first spectrum S1(k) of the band 0 <= k < FL in various ways to change the dynamic range so that a way of deformation for obtaining an appropriate dynamic range is checked. The information concerning the deformation is encoded and given to a multiplexing unit (115). By using a second spectrum S2(k) having a valid signal band 0 <= k <FH as a reference signal, an extended band spectrum encoding unit (114) estimates a spectrum (spectrum of extended band) to be contained in the higher range (FL <= k < FH) of the first spectrum S1(k) according to the first spectrum S1'(k) after the deformation, encodes the information concerning the estimation spectrum, and gives it to the multiplexing unit (115).

Description

Code device, decoding device and coding/decoding method

Technical field

The present invention relates to voice signal, sound signal etc. is carried out code device, decoding device and the coding/decoding method of coding/decoding.

Background technology

With the speech coding technology that voice signal compresses by low bit rate, electric wave etc. of effective utilization carry out to(for) mobile communications is very important.Particularly as in recent years trend, the expectation that the quality that improves call voice is expressed increases day by day, and hope can realize having the session services of the sense of reality of height.The environment of staying for the speaker in the sense of reality of this indication (such as BGM) therefore wishes also can encode in high quality to the signal outside the voice of audio frequency etc.

In speech coding technology with speech signal coding, exist G726, G729 etc. by the standardized mode of ITU-T (International Telecommunication Union Telecommunication StandardizationSector).These modes are that (300Hz～3.4kHz) is an object, can encode by 8kbit/s～32kbit/s with narrow band signal.Though these modes can be encoded by low bit rate, maximum as the frequency domain of the narrow band signal of coded object, still too narrow only to 3.4KHz, so its quality can not improve and causes lacking the sense of reality.

In addition, existing signal band in ITU-T and 3GPP (The 3rd Generation Partnership Project) is the voice of the 50Hz～7kHz standard mode of encoding (G.722, G.722.1, AMR-WB etc.).Though these modes can be carried out the coding of wideband speech signal by the bit rate of 6.6kbit/s～64kbit/s, wideband speech signal is encoded in high quality need relative raising bit rate.And, have high tone quality though broadband voice is compared with narrowband speech from the angle of tonequality, enough hardly to the service of the sense of reality that requires height.

In general, when the maximum frequency of signal reaches 10～15kHz left and right sides, the sense of reality that is equivalent to FM broadcasting can be accessed, and when reaching the 20kHz left and right sides, the quality that is equivalent to CD can be accessed.For the signal with frequency band like this, normalized by MPEG (Moving Picture Expert Group) is that the audio coding mode of representative is more suitable with layer 3 mode and AAC mode etc.But,, need to set high bit rate so that voice are encoded in high quality if the coded system of these audio coding modes as voice communication adopted.Also can encode in addition and delay becoming the problem of big grade.

Carry out Methods for Coding as signal in high quality by low bit rate with wide frequency domain, has following technology: two frequency spectrums that the frequency spectrum of input signal are divided into low frequency part and HFS, then low-frequency spectra is duplicated and replaces high frequency spectrum (high frequency spectrum is substituted by low-frequency spectra), reduce whole bit rate (for example with reference to patent documentation 1) thus.This technology is used for more Bit Allocation in Discrete the coding of low-frequency spectra and carries out high-quality coding, on the contrary, then carries out the low-frequency spectra base conditioning of duplicating behind the coding can be encoded by less Bit Allocation in Discrete thus for high frequency spectrum.

In addition, as with this technology similar techniques, also have following technology:, utilize other predetermined frequent spectrum information of part to carry out approximate processing and improve the quality (for example with reference to patent documentation 2) to the abundant frequency band of allocated code bit.Do not make it become broadband signal having under the situation of additional information narrow band signal to be carried out band spread, therefore the low-frequency spectra of narrow band signal is replicated in high frequency spectrum and is used as base conditioning (for example with reference to patent documentation 3).

Moreover no matter in which kind of technology, all the frequency spectrum with other frequency band duplicates, and after the gain adjustment of carrying out being used to make spectral enveloping line become level and smooth, this replica spectra insertion need be carried out the frequency band that frequency spectrum replenishes.

[patent documentation 1] Japanese patent application laid table 2001-521648 communique

The flat 9-153811 communique of [patent documentation 2] Japanese Patent Application Laid-Open

The flat 9-90992 communique of [patent documentation 3] Japanese Patent Application Laid-Open

Summary of the invention

Problem to be addressed by invention

But in the frequency spectrum of voice signal or sound signal, the phenomenon that the dynamic range of low-frequency spectra (maximal value of the absolute value of spectral amplitude (absolute amplitude) and the ratio of minimum value) is bigger than the dynamic range of high frequency spectrum is very common.Fig. 1 is the figure that is used for illustrating this phenomenon, and it shows an example of the frequency spectrum of sound signal.This frequency spectrum is the log spectrum the when sound signal of sample frequency 32kHz is carried out frequency analysis by the length of 30ms.

As shown in the drawing, frequency is the low-frequency spectra peak value of 0～8000Hz very strong (having a plurality of sharp keen spectrum peaks), and is very big in the dynamic range of the frequency spectrum of this frequency band.In contrast, frequency is that the dynamic range of high frequency spectrum of 8～15000Hz is then very little.To having the signal of such spectral characteristic, if utilize traditional method that low-frequency spectra is replicated in high frequency spectrum, even carry out the gain adjustment of high frequency spectrum, also following phenomenon can appear, unnecessary spectrum peak shape promptly appears in high frequency spectrum.

Fig. 2 for expression will be as shown in Figure 1 the low-frequency spectra of frequency spectrum (1000～7000Hz) duplicate, and obtain the high frequency spectrum (figure of the full range band frequency spectrum 10000～16000Hz) time by the power adjustment.

As shown in the drawing, when carrying out above-mentioned processing, at the frequency band R1 that is higher than 10000Hz unnecessary spectrum peak shape has appearred.This spectrum peak is unexistent in the original high frequency spectrum.And, in the decoded signal that this spectrum transformation is obtained to time domain, noise like the bell ring can take place, and the problem that causes subjective quality to reduce.As mentioned above, in the technology that the frequency spectrum of certain frequency band frequency spectrum by other frequency band is substituted, need to adjust rightly the dynamic range of inserting frequency spectrum.

Therefore, the present invention aims to provide a kind of code device, decoding device and coding/decoding method, in that the frequency spectrum of certain frequency band frequency spectrum by other frequency band is substituted in the technology of (displacement), can adjust the subjective quality that the dynamic range of inserting frequency spectrum improves decoded signal rightly.

The scheme that addresses this problem

Code device of the present invention adopts a kind of like this structure, and it comprises: coding unit, the high frequency spectrum of input signal is partly encoded; And limiting unit, the coded signal of the low-frequency spectra of described input signal part is decoded and obtained first low-frequency spectra, and the amplitude that as one man limits this first low-frequency spectra generates second low-frequency spectra, wherein, described coding unit carries out the coding of described high frequency spectrum part based on described second low-frequency spectra.

In addition, decoding device of the present invention adopts a kind of like this structure, it comprises: converter unit will become frequency-region signal to generate first low-frequency spectra to the decode signal transformation of gained of the coding that is contained in the low-frequency spectra part in the coding that generates by code device; Decoding unit is decoded to the coding that is contained in the high frequency spectrum part in the coding that generates by described code device; And limiting unit, according to the spectrum modifying information that is contained in the coding that generates by described code device, as one man the amplitude of described first low-frequency spectra is limited and generate second low-frequency spectra, wherein, described decoding unit is decoded to the coding of described high frequency spectrum part based on described second low-frequency spectra.

In addition, decoding device of the present invention adopts a kind of like this structure, comprise: converter unit will become frequency-region signal to generate first low-frequency spectra to the decode signal transformation of gained of the coding that is contained in the low-frequency spectra part in the coding that generates by code device; Decoding unit is decoded to the coding that is contained in the high frequency spectrum part in the coding that generates by described code device; And limiting unit, amplitude to described first low-frequency spectra carries out the consistance restriction and generates second low-frequency spectra, wherein, described limiting unit is estimated the information of relevant ways to restrain based on described first low-frequency spectra, and utilize the information that estimates to generate described second low-frequency spectra, and described decoding unit is decoded to the coding of described high frequency spectrum part based on described second low-frequency spectra.

The beneficial effect of the invention

According to the present invention, in the technology that the frequency spectrum of certain frequency band frequency spectrum by other frequency band is substituted, can adjust the dynamic range of inserting frequency spectrum rightly and the subjective quality that improves decoded signal.

Description of drawings

Fig. 1 is the figure of example of the frequency spectrum of expression sound signal.

Fig. 2 duplicates low-frequency spectra and carries out the power adjustment figure of the frequency spectrum of the full range band when obtaining high frequency spectrum for expression.

Fig. 3 is the block scheme of primary structure of the code device of expression embodiment 1.

Fig. 4 is the block scheme of primary structure of the inside, spectrum coding unit of expression embodiment 1.

Fig. 5 is the block scheme of primary structure of the inside, spectrum modifying unit of expression embodiment 1.

Fig. 6 is the block scheme of primary structure of the deformation unit inside of expression embodiment 1.

Fig. 7 is the figure of the example that passes through the distortion frequency spectrum that deformation unit obtains of expression embodiment 1.

Fig. 8 is the block scheme of structure of other version of the deformation unit of expression embodiment 1.

Fig. 9 is the block scheme of primary structure of the hierarchical decoding device of expression embodiment 1.

Figure 10 is the block scheme of primary structure of the frequency spectrum decoding unit inside of expression embodiment 1.

Figure 11 is the block scheme that expression is used to illustrate the spectrum coding unit of embodiment 2.

Figure 12 is the block scheme of structure of other version of the spectrum coding unit of expression embodiment 2.

Figure 13 is the block scheme of primary structure of the frequency spectrum decoding unit of expression embodiment 2.

Figure 14 is the block scheme of primary structure of the spectrum coding unit of expression embodiment 3.

Figure 15 is the block scheme that expression is used to illustrate the deformation information estimation unit of embodiment 3.

Figure 16 is the block scheme of primary structure of the deformation unit of expression embodiment 3.

Figure 17 is the block scheme of primary structure of the frequency spectrum decoding unit of expression embodiment 3.

Figure 18 is the block scheme of primary structure of the hierarchy encoding apparatus of expression embodiment 4.

Figure 19 is the block scheme of primary structure of the spectrum coding unit of expression embodiment 4.

Figure 20 is the block scheme of primary structure of the hierarchical decoding device of expression embodiment 4.

Figure 21 is the block scheme of primary structure of the frequency spectrum decoding unit of expression embodiment 4.

Figure 22 is the figure of primary structure of the spectrum coding unit of expression embodiment 5.

Figure 23 is the block scheme of primary structure of the information converting estimation unit of expression embodiment 5.

Figure 24 is the figure of primary structure of the frequency spectrum decoding unit of expression embodiment 5.

Figure 25 is the figure that is used to illustrate the spectrum modifying method of embodiment 6.

Figure 26 is the block scheme of primary structure of the inside, spectrum modifying unit of expression embodiment 6.

Figure 27 is the figure that is used to illustrate the generation method of being out of shape frequency spectrum.

Figure 28 is the figure that is used to illustrate the generation method of being out of shape frequency spectrum.

Figure 29 is the block scheme of primary structure of the inside, spectrum modifying unit of expression embodiment 6.

Embodiment

Below, the embodiment that present invention will be described in detail with reference to the accompanying.

(embodiment 1)

Fig. 3 is the block scheme of primary structure of the hierarchy encoding apparatus 100 of expression embodiment of the present invention 1.At this, have the situation of the hierarchy that constitutes by multilayer with coded message, the situation of just carrying out hierarchical coding (scalable coding) is that example illustrates.

The various piece of hierarchy encoding apparatus 100 is along with following action is carried out in the input of signal.

Downsampling unit 101 generates the signal of low sampling rate according to input signal, and offers ground floor coding unit 102.102 pairs of signals from downsampling unit 101 outputs of ground floor coding unit are encoded.To offer Multiplexing Unit 103 and ground floor decoding unit 104 by the coded identification that ground floor coding unit 102 obtains.Then, ground floor decoding unit 104 generates ground floor decoded signal S1 according to the coded identification of ground floor coding unit 102 outputs.

On the other hand, delay cell 105 is given input signal with the delay of predetermined length.This delay is used for proofreading and correct the time delay that produces at downsampling unit 101, ground floor coding unit 102 and ground floor decoding unit 104.Spectrum coding unit 106 utilizes the ground floor decoded signal S1 that is generated by ground floor decoding unit 104, to carrying out spectrum coding, and the coded identification that generates is outputed to Multiplexing Unit 103 by delay cell 105 input signal S2 output, the delayed schedule time.

103 pairs of Multiplexing Units are undertaken multiplexing by ground floor coding unit 102 coded identification of obtaining and the coded identification of being obtained by spectrum coding unit 106, and it is outputed to the outside of code device 100 as the output encoder symbol.

Fig. 4 is the block scheme of the primary structure of expression 106 inside, above-mentioned spectrum coding unit.

This spectrum coding unit 106 mainly comprises: frequency-domain transform unit 111, spectrum modifying unit 112, frequency-domain transform unit 113, extending bandwidth spectrum coding unit 114 and Multiplexing Unit 115.

Spectrum coding unit 106 receives from ground floor decoding unit 104 has the first signal S1 that the useful signal frequency band is 0≤k＜FL (k is the frequency of each subband), and receives from delay cell 105 that to have the useful signal frequency band be 0≤k＜FH (secondary signal S2 of FL＜FH) wherein.Spectrum coding unit 106 utilizes the frequency spectrum of frequency band 0≤k＜FL of the first signal S1 to estimate the frequency spectrum of frequency band FL≤k＜FH of secondary signal S2, and this estimated information is encoded and exported.

The first signal S1 of 111 pairs of inputs of frequency-domain transform unit carries out frequency transformation, calculates the first frequency spectrum S1 (k) of low-frequency spectra.On the other hand, the secondary signal S2 of 113 pairs of inputs of frequency-domain transform unit carries out frequency transformation, calculates the second frequency spectrum S2 (k) in broadband.The method of frequency transformation described herein is suitable for discrete Fourier transform (DFT) (DFT), discrete cosine transform (DCT) and distortion discrete cosine transform (MDCT) etc.In addition, S1 (k) is the frequency spectrum of subband of frequency spectrum, frequency k that S2 (k) is second frequency spectrum of subband of the frequency k of first frequency spectrum.

Spectrum modifying unit 112 carries out the dynamic range that various distortion change first frequency spectrum with the first frequency spectrum S1 (k), thereby investigation is as the deformation method of appropriate dynamic range.And, the information (deformation information) of relevant this distortion is encoded and offer Multiplexing Unit 115.The detailed content that relevant this spectrum modifying is handled will be narrated in the back.In addition, spectrum modifying unit 112 outputs to extending bandwidth spectrum coding unit 114 with the first frequency spectrum S1 (k) that dynamic range becomes appropriate.

Extending bandwidth spectrum coding unit 114 with the second frequency band S2 (k) as contrast signal, estimation should be contained in the high frequency (frequency spectrum (extending bandwidth frequency spectrum) of FL≤k＜FH), and the information (estimated information) of relevant this estimated spectral encoded offer Multiplexing Unit 115 of the first frequency spectrum S1 (k).At this, the estimation of extending bandwidth frequency spectrum (k) is carried out based on the first frequency spectrum S1 ' after being out of shape.

Then, Multiplexing Unit 115 is with by the coded identification of the deformation information of spectrum modifying unit 112 output and undertaken multiplexing and output by the coded identification of the estimated information of the relevant extending bandwidth frequency spectrum of extending bandwidth spectrum coding unit 114 outputs.

Fig. 5 is the block scheme of the primary structure of expression 112 inside, above-mentioned spectrum modifying unit.

The 112 couples first frequency spectrum S1 in spectrum modifying unit (k) apply distortion, and this is deformed into the high frequency spectrum that the dynamic range that makes the first frequency spectrum S1 (k) approaches the second frequency spectrum S2 (k) most (distortion of the dynamic range of FL≤k＜FH).Next, the deformation information of this moment is encoded and exported.

The first frequency spectrum S1 (k) of buffer cell 121 temporary transient storage inputs, and as required the first frequency spectrum S1 (k) is offered deformation unit 122.

Deformation unit 122 is according to following step, the first frequency spectrum S1 (k) carried out various distortion generate the first frequency spectrum S1 ' (j k), and provides it to subband power calculation unit 123.At this, j is the index that is used for discerning various deformation process.

Subband power calculation unit 123 will be out of shape the first frequency spectrum S1 ', and (j, frequency domain k) is divided into a plurality of subbands, and obtains the power (subband power) of the subband of preset range.For example, when the scope of finding the solution subband power is set at F1L≤k＜F1H, this bandwidth is carried out the subband wide BWS of N when cutting apart be expressed as following formula (formula 1).

BWS=(F1H-F1L+1)/N (formula 1)

Therefore, the minimum frequency F1L (n) of n subband and maximum frequency F1H (n) are expressed as (formula 2) and (formula 3) respectively.

F1L (n)=F1L+nBWS (formula 2)

F1H (n)=F1L+ (n+1) BWS-1 (formula 3)

Wherein, n gets the value of 0～N-1.

At this moment, (j is n) as shown in the formula calculating shown in (formula 4) for subband power P 1.

$P1(j,n)=\frac{\underset{k=F1L\left(n\right)}{\overset{F1H\left(n\right)}{\mathrm{\&Sigma;}}}{S1}^{\&prime;}{(j,k)}^2}{\mathrm{BWS}}$ (formula 4)

In addition, also can be as shown in the formula the mean value that calculates the frequency spectrum that is contained in subband shown in (formula 5).

$P1(j,n)=\sqrt{\frac{\underset{k=F1L\left(n\right)}{\overset{F1H\left(n\right)}{\mathrm{\&Sigma;}}}{S1}^{\&prime;}{(j,k)}^2}{\mathrm{BWS}}}$ (formula 5)

(j n) offers variance computing unit 124 to the subband power P 1 that will obtain as mentioned above then.

Variance computing unit 124 is in order to represent that (j, extent of deviation n) calculate variances sigma 1 according to following formula (formula 6) to subband power P 1 ²(j).

${\mathrm{\&sigma;}1}^2\left(j\right)=\underset{n=0}{\overset{N-1}{\mathrm{\&Sigma;}}}{(P1(j,n)-\mathrm{Plmean}\left(j\right))}^2$ (formula 6)

At this, P1mean (j) expression subband power P 1 (j, mean value n), and calculate as shown in the formula (formula 7).

$\mathrm{Plmean}\left(j\right)=\frac{\underset{n=0}{\overset{N-1}{\mathrm{\&Sigma;}}}P1(j,n)}{N}$ (formula 7)

The variances sigma 1 of the extent of deviation of the subband power of the expression deformation information j that will calculate as mentioned above then ²(j) offer search unit 125.

Subband power calculation unit 126 and variance computing unit 127, carry out the identical processing of a series of processing carried out with above-mentioned subband power calculation unit 123 and variance computing unit 124:, calculate the variances sigma 2 of the extent of deviation of expression subband power to the second frequency spectrum S2 (k) of input ²(j).But, the processing carried out of subband power calculation unit 126 and variance computing unit 127 and above-mentioned processing do not exist together as described below.Just, the specialized range that will calculate the subband power of the second frequency spectrum S2 (k) is set at F2L≤k＜F2H.At this, because be necessary to make the dynamic range of the dynamic range of first frequency spectrum, so set F2L to satisfy FL≤F2L＜F2H near the high frequency spectrum of second frequency spectrum.And, there is no need to make corresponding to the quantity of the subband of second frequency spectrum consistent with the quantity N of the subband of first frequency spectrum.But, the sub band number of setting second frequency spectrum make the subband of first frequency spectrum wide with the wide basically identical of subband second frequency spectrum.

Search unit 125 is determined the variances sigma 1 of the subband of first frequency spectrum by search ²(j), make the variances sigma 1 of the subband of first frequency spectrum ²(j) with the variances sigma 2 of the subband of second frequency spectrum ²(j) the most approaching.Specifically, 125 couples of all distortion candidate 0≤j＜J of search unit calculate the variances sigma 1 of the subband of first frequency spectrum ²(j), with the variances sigma 2 of the subband of this calculated value and second frequency spectrum ²(j) compare, determine both the most near the time the value (optimum deformation information jopt) of j, and this jopt is outputed to the outside and the deformation unit 128 of spectrum modifying unit 112.

Deformation unit 128 generates the first frequency spectrum S1 ' through distortion corresponding to this optimum deformation information jopt, and (jopt k), and outputs to the outside of spectrum modifying unit 112 with it.Optimum deformation information jopt is transferred to Multiplexing Unit 115, and transmission (jopt is k) to extending bandwidth spectrum coding unit 114 through the first frequency spectrum S1 ' of distortion.

Fig. 6 is the block scheme of the primary structure of the above-mentioned deformation unit of expression 122 inside.And the inner structure of deformation unit 128 is identical with deformation unit 122 basically.

Positive sign/negative sign extraction unit 131 is obtained the symbolic information sign (k) of each subband of first frequency spectrum, and outputs to positive sign/negative sign and give unit 134.

Each subband of 132 pairs first frequency spectrums of absolute value calculation unit calculates the absolute value of amplitude, and this value is offered exponential quantity computing unit 133.

Index variable form 135 records are used for the index variable α (j) of the distortion of first frequency spectrum.Be contained in the pairing value of j in the variable of this form from 135 outputs of index variable form.Specifically, in index variable form 135, for example writing down the index variable candidate of forming by 4 index variablees, it is index variable α (j)={ 1.0,0.8,0.6,0.4}, according to index j, select wherein 1 index variable α (j), and offer exponential quantity computing unit 133 by search unit 125 appointments.

Exponential quantity computing unit 133 utilizes from the index variable of index variable form 135 outputs, calculating just calculates the value of the absolute value of amplitude of each subband being carried out the inferior power gained of α (j) from the exponential quantity of the frequency spectrum (absolute value) of absolute value calculation unit 132 outputs.

Positive sign/negative sign is given unit 134, to the exponential quantity of exponential quantity computing unit 133 outputs, gives by positive sign/negative sign extraction unit 131 in the symbolic information sign that had before obtained (k), as the distortion first frequency spectrum S1 ' (j, k) output.

Therefore, (j k) represents as shown in the formula (formula 8) the distortion first frequency spectrum S1 ' that is exported by deformation unit 122.

S1 ' (j, k)=sign (k) | S1 (k) | ^{A (j)}(formula 8)

The figure of the example of the distortion frequency spectrum that Fig. 7 obtains by above-mentioned deformation unit 122 (or deformation unit 128) for expression.

Here, index variable α (j)={ 1.0,0.6, the situation of 0.2} is that example describes to get.In addition, at this for each frequency spectrum relatively easily, with α (j)=1.0 o'clock the frequency spectrum S71 40dB that moved up, with α (j)=0.6 o'clock the frequency spectrum S72 20dB that moved up.Can learn from this figure, can change the dynamic range of frequency spectrum by index variable α (j).

As mentioned above, code device (spectrum coding unit 106) according to present embodiment, use by first signal (first frequency spectrum of 0≤k＜FL) obtain, estimate the secondary signal (HFS of second frequency spectrum of 0≤k＜FH) obtain (FL≤k＜FH), and when estimated information encoded, directly do not use first frequency spectrum but carry out above-mentioned estimation again after first frequency spectrum applied distortion.At this moment, the information (deformation information) how expression is out of shape is also encoded in the lump, be transferred to decoding end.

The concrete grammar that first frequency spectrum is applied distortion is, first frequency spectrum is divided into subband, each subband is obtained average (the sub-band averaging amplitude) of the absolute amplitude of the frequency spectrum that is contained in each subband, with first spectrum modifying so that these average amplitude are carried out statistical treatment and the variance obtained is the most approaching with the variance of the sub-band averaging amplitude of obtaining equally according to the frequency spectrum of the HFS of second frequency spectrum.Just, with first spectrum modifying so that the average hunting range of the absolute amplitude of first frequency spectrum becomes the value that equates with the average hunting range of the absolute amplitude of the high frequency spectrum of second frequency spectrum.And, the deformation information of representing the deformation method that this is concrete is encoded.In addition, also can utilize the power of the frequency spectrum that is contained in each subband to replace the sub-band averaging amplitude.

Further specifically, above-mentioned concrete deformation method is exactly to carry out α power (0≤α≤1) by the frequency spectrum to first frequency spectrum, controls the deviation (swing) of the absolute amplitude of the frequency spectrum in the subband.And, with the information transmission of relevant employed α to decoding end.

By adopting said structure, even when the dynamic range of the HFS of the dynamic range of first frequency spectrum and second frequency spectrum varies in size, also can adjust the dynamic range of estimated spectral rightly, improve the subjective quality of decoded signal thus.

In addition, in above-mentioned structure, by the first frequency spectrum integral body being carried out α power (0≤α≤1), the amplitude of frequency spectrum is applied the consistance restriction.Spectrum peak that thus can passivation sharp keen (precipitous).In addition, for example just the spectrum peak more than the predetermined value is disappeared the peak and when being out of shape, might cause frequency spectrum to become discontinuous and produce strange noise, but by adopting above-mentioned structure, then can make frequency spectrum become level and smooth and prevent strange noise.

In addition, in the present embodiment, situation when using variance as the index of degree (amplitude of fluctuation) of the deviation of the absolute amplitude of expression frequency spectrum is illustrated as example, but the present invention has more than and be limited to this, for example (,) also can the applied code deviation etc. other index.

In addition, in the present embodiment, in the deformation unit 122 (or deformation unit 128) of code device 100, to use the situation of exponential function to be illustrated as example, the method that illustrates below still also can using.

Fig. 8 is the block scheme of structure of other versions (deformation unit 122a) of expression deformation unit.Give identical numbering for the inscape identical, and omit its explanation with deformation unit 122 (or deformation unit 128).

In above-mentioned deformation unit 122 (or deformation unit 128), because use exponential function, so calculated amount has the trend that becomes big.So, avoid the increase of calculated amount by the method for not using exponential function to change the dynamic range of frequency spectrum.

Absolute value calculation unit 132 is calculated the absolute value of each frequency spectrum of the first frequency spectrum S1 (k) that imports, and it is outputed to average calculation unit 142 and distortion frequency spectrum computing unit 143.Average calculation unit 142 is calculated the average absolute S1mean of frequency spectrum according to following formula (formula 9).

$\mathrm{Slmean}=\underset{k=0}{\overset{\mathrm{FL}-1}{\mathrm{\&Sigma;}}}\left|S1\left(k\right)\right|$ (formula 9)

Writing down the candidate of the multiplier that is used to be out of shape frequency spectrum computing unit 143 in the multiplier form 144, selecting a multiplier, and outputing to distortion frequency spectrum computing unit 143 based on the index of search unit 125 appointments.At this, suppose writing down in the multiplier form multiplier g (j)=1.0 .0.9,0.8,4 candidates of 0.7}.

Distortion frequency spectrum computing unit 143 utilizes the absolute value and the multiplier g (j) that is exported by multiplier form 144 by first frequency spectrum of absolute value calculation unit 132 outputs, to be out of shape frequency spectrum S1 ' absolute value (k) and calculate, and output to positive sign/negative sign and give unit 134 by following formula (formula 10).

| S1 ' (j, k) |=g (j) | S1 (k) |+(1-g (j)) S1mean (formula 10)

Positive sign/negative sign is given unit 134 will be given distortion frequency spectrum S1 ' absolute value (k) by 143 outputs of distortion frequency spectrum computing unit by the symbolic information sign (k) that positive sign/negative sign extraction unit 131 obtains, generate and output by the last distortion frequency spectrum S1 ' of following formula (formula 11) expression (k).

S1 ' (j, k)=sign (k) | S1 ' (j, k) | (formula 11)

In addition,, comprise that with deformation unit it is that example is illustrated that positive sign/negative sign extraction unit, absolute value calculation unit, positive sign/negative sign are given the situation of unit in present embodiment, but constant when the frequency spectrum of input for timing, do not need these structures.

Next, describe the structure of hierarchical decoding device 150 in detail, this decoding device can be decoded to the coded identification that is generated by above-mentioned hierarchy encoding apparatus 100.

Fig. 9 is the block scheme of primary structure of the hierarchical decoding device 150 of expression present embodiment.

The coded identification of 151 pairs of inputs of separative element is carried out separating treatment, and generates coded identification S51 that is used for ground floor decoding unit 152 and the coded identification S52 that is used for frequency spectrum decoding unit 153.The coded identification that 152 utilizations of ground floor decoding unit obtain by separative element 151 decodes the decoded signal of signal band 0≤k＜FL, and this decoded signal S53 is offered frequency spectrum decoding unit 153.In addition, the output of ground floor decoding unit 152 is connected in the lead-out terminal of decoding device 150 simultaneously.Thus, when needs are exported the ground floor decoded signal that is generated by ground floor decoding unit 152, can be via this lead-out terminal output.

Offer frequency spectrum decoding unit 153 by separative element 151 isolated coded identification S52 and the ground floor decoded signal S53 that exports by ground floor decoding unit 152.Frequency spectrum decoding unit 153 carries out frequency spectrum decoding described later, generates the wideband decoded signal of signal band 0≤k＜FH, and with its output.In frequency spectrum decoding unit 153, the ground floor decoded signal S53 that will be provided by ground floor decoding unit 152 is as first signal and handle.

Figure 10 is the block scheme of the primary structure of the above-mentioned frequency spectrum decoding unit of expression 153 inside.

This frequency spectrum decoding unit 153 input coding symbol S52 and ground floor decoded signal S53 (effectively frequency domain is first signal of 0≤k＜FL).

Separative element 161 is from the coded identification S52 of input, the deformation information and the extending bandwidth spectrum coding information separated that will be generated by the spectrum modifying unit 112 of above-mentioned coding side come, deformation information is outputed to deformation unit 162, extending bandwidth spectrum coding information is outputed to extending bandwidth frequency spectrum generation unit 163.

The ground floor decoded signal S53 of the time-domain signal of 164 pairs of inputs of frequency-domain transform unit carries out frequency transformation and calculates the first frequency spectrum S1 (k).The method of this frequency transformation is used discrete Fourier transform (DFT) (DFT), discrete cosine transform (DCT) and distortion discrete cosine transform (MDCT) etc.

Deformation unit 162 applies distortion to the first frequency spectrum S1 (k) that is provided by frequency-domain transform unit 164 and generates the distortion first frequency spectrum S1 ' (k) based on the deformation information that is provided by separative element 161.In addition, the structure of these deformation unit 162 inside is the same with the deformation unit 122 (with reference to Fig. 6) of the coding side that had illustrated already, therefore omits its explanation.

Extending bandwidth frequency spectrum generation unit 163, the first frequency spectrum S1 ' after the utilization distortion (k), generation should be contained in the estimated value S2 of second frequency spectrum of extending bandwidth FL≤k＜FH of the first frequency spectrum S1 (k) " (k), and with the estimated value S2 of this second frequency spectrum " (k) offer frequency spectrum and constitute unit 165.

Frequency spectrum constitutes unit 165 will be by the estimated value S2 of frequency-domain transform unit 164 first frequency spectrum S1 (k) that provides and second frequency spectrum that is provided by extending bandwidth frequency spectrum generation unit 163 " (k) combine and generate decoding frequency spectrum S3 (k).This decoding frequency spectrum S3 (k) is as shown in the formula shown in (formula 12).

(formula 12)

This decoding frequency spectrum S3 (k) offers spatial transform unit 166.

Spatial transform unit 166 will be after decoding frequency spectrum S3 (k) be transformed to time-domain signal, window as required (windowing) and superpose processing such as (superposition addition), avoiding that between frame discontinuous phenomenon takes place, and export last decoded signal.

As mentioned above, according to the decoding device (frequency spectrum decoding unit 153) of present embodiment, can be to decoding by the code device encoded signals of present embodiment.

(embodiment 2)

In embodiments of the present invention 2, the pitch filter that utilization is held first frequency spectrum as internal state is estimated second frequency spectrum, and the characteristic of this pitch filter is encoded.

Therefore the structure of the hierarchy encoding apparatus of present embodiment is identical with the hierarchy encoding apparatus shown in the embodiment 1, utilizes the block scheme of Figure 11 to come the difference of description architecture, and promptly the spectrum coding unit 201.And, give identical numbering for the inscape identical, and omit its explanation with the spectrum coding unit 106 (with reference to Fig. 4) shown in the embodiment 1.

Internal state setup unit 203 uses the distortion first frequency spectrum S1 ' by 112 generations of spectrum modifying unit (k) to set the internal state S (k) that is used for filter unit 204.

Filter unit 204 carries out filtering based on internal state S (k) that is set by internal state setup unit 203 and the retardation coefficient T that is provided by retardation coefficient setup unit 206, and calculates the estimated value S2 of second frequency spectrum " (k).In addition, present embodiment describes the situation of using the wave filter of representing by following formula (formula 13).

(formula 13)

At this, the coefficient that is provided by retardation coefficient setup unit 206 is provided T, and hypothesis M=1.Shown in (formula 14), the Filtering Processing of filter unit 204 is multiplied by corresponding factor beta with the frequency spectrum that has reduced frequency T as the center by main the use according to ascending order _iAnd carry out addition, calculate estimated value.

$S\left(k\right)=\underset{i=1}{\overset{1}{\mathrm{\&Sigma;}}}{\mathrm{\&beta;}}_i\&CenterDot;S(k-T-i)$ (formula 14)

Processing according to this formula is carried out in the scope of FL≤k＜FH.At this, the internal state of S (k) expression wave filter.The S that calculates at this moment, (k) (wherein FL≤k＜FH) is as the estimated value S2 of second frequency spectrum " (k) use.

The estimated value S2 of second frequency spectrum S2 (k) that is provided by frequency-domain transform unit 113 and second frequency spectrum that is provided by filter unit 204 is provided for search unit 205 " (k) similarity degree.

In addition, there are various definition in this similarity degree, but in the present embodiment, uses following similarity degree: at first with filter coefficient β _-1And β ₁Be considered as 0, similarity degree defined based on least square poor (aminimum square error), that calculate according to following formula (formula 15).

$E=\underset{k=\mathrm{FL}}{\overset{\mathrm{FH}-1}{\mathrm{\&Sigma;}}}S2{\left(k\right)}^2-\frac{{(\underset{k=\mathrm{FL}}{\overset{\mathrm{FH}-1}{\mathrm{\&Sigma;}}}S2\left(k\right)\&CenterDot;S^{\&prime;\&prime;}2\left(k\right))}^2}{\underset{k=\mathrm{FL}}{\overset{\mathrm{FH}-1}{\mathrm{\&Sigma;}}}{S}^{\&prime;\&prime;}2{\left(k\right)}^2}$ (formula 15)

According to this method, after calculating optimum retardation coefficient T, determine filter coefficient β _iRepresent S2 (k) and S2 at this E " least square between (k) is poor.In addition, the fixed value that first on the right of following formula (formula 15) is and retardation coefficient T is irrelevant, therefore can search out generate second on the right that makes (formula 15) and be maximum S2 " (k) the time postpone coefficient T.In the present embodiment, second on the right of (formula 15) is called similarity degree.

The retardation coefficient T that retardation coefficient setup unit 206 will be contained in the hunting zone TMIN～TMAX that predesignates outputs to filter unit 204 successively.Therefore, in filter unit 204, when providing retardation coefficient T by retardation coefficient setup unit 206, all carry out filtering after the S of the scope with FL≤k＜FH (k) makes zero, search unit 205 then all calculates similarity degree at every turn at every turn.Coefficient T max when search unit 205 determines to make the similarity degree that calculates to be maximum from the scope of TMIN～TMAX offers filter coefficient computing unit 207, frequency spectrum profiles coding unit 208 and Multiplexing Unit 115 with this coefficient T max.

Filter coefficient computing unit 207 utilizes the coefficient T max that is provided by search unit 205 to obtain filter coefficient β _iAt this, the filter coefficient β that asks _iMake difference of two squares E become minimum according to following formula (formula 16).

$E=\underset{k=\mathrm{FL}}{\overset{\mathrm{FH}-1}{\mathrm{\&Sigma;}}}{(S2\left(k\right)-\underset{i=-1}{\overset{1}{\mathrm{\&Sigma;}}}{\mathrm{\&beta;}}_{i}S(k-T_{\max }-i))}^2$ (formula 16)

Filter coefficient computing unit 207 is with a plurality of β _iCombination hold as form in advance, determine to make the difference of two squares E of following formula (formula 16) to become minimum β _iCombination, this coding is outputed to Multiplexing Unit 115, and with filter coefficient β _iOffer frequency spectrum profiles coding unit 208.

The internal state S (k) that provided by internal state setup unit 203 is provided for frequency spectrum profiles coding unit 208, the retardation coefficient Tmax that is provided by search unit 205 and the filter coefficient β that is provided by filter coefficient computing unit 207 _i, carry out Filtering Processing, obtaining frequency band is the estimated value S2 of second frequency spectrum of FL≤k＜FH " (k).Next, frequency spectrum profiles coding unit 208 utilizes the estimated value S2 of second frequency spectrum " (k) the adjustment coefficient of frequency spectrum profiles is encoded with the second frequency spectrum S2 (k).

In the present embodiment, the situation that this frequency spectrum profiles information is represented with the spectrum power of each subband has been described.At this moment, the spectrum power of j subband is as shown in the formula shown in (formula 17).

$B\left(j\right)=\underset{k=\mathrm{BL}\left(j\right)}{\overset{\mathrm{BH}\left(j\right)}{\mathrm{\&Sigma;}}}S2{\left(k\right)}^2$ (formula 17)

At this, the minimum frequency of j subband of BL (j) expression, the maximum frequency of j subband of BH (j) expression.The spectrum power of looking the subband of second frequency spectrum of so obtaining is the frequency profile information of second frequency spectrum.

Equally, frequency spectrum profiles coding unit 208 calculates the estimated value S2 of second frequency spectrum according to following formula (formula 18) ", the spectrum power B of subband (k) " (j), and calculate the variable quantity V (j) of each subband according to following formula (formula 19).

$B^{\&prime;\&prime;}\left(j\right)=\underset{k=\mathrm{BL}\left(j\right)}{\overset{\mathrm{BH}\left(j\right)}{\mathrm{\&Sigma;}}}{S}^{\&prime;\&prime;}2{\left(k\right)}^2$ (formula 18)

$V\left(j\right)=\sqrt{\frac{B\left(j\right)}{B^{\&prime;\&prime;}\left(j\right)}}$ (formula 19)

Next, 208 couples of variable quantity V of frequency spectrum profiles coding unit (j) encode and this coding are delivered to Multiplexing Unit 115.

Multiplexing Unit 115 is with following information multiplexing and output: the deformation information that is obtained by spectrum modifying unit 112; The information of the optimal delay coefficient T max that obtains by search unit 205; The information of the filter coefficient that obtains by filter coefficient computing unit 207; The frequency spectrum profiles that is obtained by frequency spectrum profiles coding unit 208 is adjusted the information of coefficient.

As mentioned above, according to the embodiment of the present invention, utilization has as the pitch filter of first frequency spectrum of internal state estimates second frequency spectrum, therefore only need encode to the characteristic of this pitch filter, just can realize low bit rate.

In the present embodiment, although understand the situation comprise frequency-domain transform unit, but these structures be with time domain required structure when importing, and when direct input spectrum, then need not frequency-domain transform unit.

In addition, though present embodiment situation with M=1 in above-mentioned (formula 13) is that example is illustrated, the value of M not only is defined as 1, can use the integer more than 0.

In addition, be that example is illustrated though present embodiment is utilized the situation of the filter function (transport function) of above-mentioned (formula 13) with pitch filter, pitch filter also can be pitch filter once.

Figure 12 is the block scheme of structure of other version (spectrum coding unit 201a) of the spectrum coding unit 201 of expression embodiment.And, give identical numbering for the inscape identical, and omit its explanation with spectrum coding unit 201.

The wave filter that is used for filter unit 204 is equally simple as shown in the formula (formula 20).

$P$ $\left(z\right)=\frac{1}{1-z^{-T}}$ (formula 20)

This formula is in above-mentioned (formula 13), gets M=0, β _o=1 o'clock filter function.

The estimated value S2 of second frequency spectrum that generates by this wave filter " (k) can utilize following formula (formula 21), the low-frequency spectra that leaves the internal state S (k) of T is duplicated successively and obtains.

S (k)=S (k-T) (formula 21)

In addition, search unit 205 makes above-mentioned (formula 15) become minimum coefficient T with above-mentioned search similarly and determines optimum coefficient T max.The coefficient T max that so obtains offers Multiplexing Unit 115.

By adopting said structure, the Filter Structures that is used for filter unit 204 can become easy, and need not filter coefficient computing unit 207, therefore carries out the estimation of second frequency spectrum by less calculated amount.Just, according to this structure, the structure of code device becomes easy, therefore can reduce the calculated amount of encoding process.

Next, describe the structure of the frequency spectrum decoding unit 251 of decoding end in detail, this frequency spectrum decoding unit can be decoded to the coded identification that is generated by above-mentioned spectrum coding unit 201 (or spectrum coding unit 201a).

Figure 13 is the block scheme of primary structure of the frequency spectrum decoding unit 251 of expression present embodiment.And this frequency spectrum decoding unit 251 has and the identical basic structure of frequency spectrum decoding unit 153 (with reference to Figure 10) shown in the embodiment 1, gives identical numbering for identical inscape, and omits its explanation.Difference is the inner structure of extending bandwidth frequency spectrum generation unit 163a.

Internal state setup unit 252 uses the first frequency spectrum S1 ' after the distortion of deformation units 162 outputs (k) to set the internal state S (k) of the wave filter that is used for filter unit 253.

Filter unit 253 obtains the information of relevant wave filter according to the coded identification that the spectrum coding unit 201 (201a) by coding side generates via separative element 161.Specifically, when using spectrum coding unit 201, obtain retardation coefficient Tmax and filter coefficient β _iWhen using spectrum coding unit 201a, have to retardation coefficient Tmax.And the distortion first frequency spectrum S1 ' that filter unit 253 will be generated by deformation unit 162 is (k) as the internal state S (k) of wave filter, carries out filtering and calculates decoding frequency spectrum S based on the filter information that obtains " (k).This filtering method depends on the used filter function in spectrum coding unit 201 (201a) of coding side, when using spectrum coding unit 201, also carry out filtering in decoding end according to above-mentioned (formula 13), and when using spectrum coding unit 201a, also carry out filtering according to above-mentioned (formula 20) in decoding end.

Frequency spectrum profiles decoding unit 254 is based on the frequency spectrum profiles information that is provided by the separative element 161 frequency spectrum profiles information of decoding.Present embodiment illustrates as example with the situation of the quantized value Vq (j) of the variable quantity that uses each subband.

The decoding frequency spectrum S that frequency spectrum adjustment unit 255 is being obtained by filter unit 253 " (k) on; be multiplied by the quantized value Vq (j) of the variable quantity of each subband that obtains by frequency spectrum profiles decoding unit 254 according to following formula (formula 22); adjust frequency spectrum S thus " spectral shape of (k) frequency domain FL≤k＜FH, and generate the estimated value S2 of second frequency spectrum " (k).

S " 2 (k)=S " is V (k) _q(j) (BL (j)≤k≤BH (j), for all j) (formula 22)

At this, BL (j) and BH (j) represent minimum frequency, the maximum frequency of j subband respectively.The estimated value S2 of second frequency spectrum that will calculate according to above-mentioned (formula 22) " (k) offer frequency spectrum and constitute unit 165.

Frequency spectrum constitutes unit 165 as described at embodiment 1, with the estimated value S2 of the first frequency spectrum S1 (k) with second frequency spectrum " (k) combine and generate decoding frequency spectrum S3 (k), and offer spatial transform unit 166.

As mentioned above, according to the decoding device (frequency spectrum decoding unit 251) of present embodiment, can be to decoding by the code device encoded signals of present embodiment.

(embodiment 3)

Figure 14 is the block scheme of primary structure of the spectrum coding unit of expression embodiment of the present invention 3.In Figure 14, the module that has same names and identical numbering with Fig. 4 has identical functions, therefore omits its explanation.In present embodiment 3, adjust the dynamic range of frequency spectrum based on coding side, the shared information of decoding end.Therefore, need not to export the coded identification of the dynamic range coefficients of the dynamic range of representing the adjustment frequency spectrum.Because need not to export the coded identification of the dynamic range coefficients of the dynamic range that will represent to adjust frequency spectrum, so can reduce bit rate.

Spectrum coding unit 301 among Figure 14 has dynamic range computing unit 302, deformation information estimation unit 303 and deformation unit 304 and replaces spectrum modifying unit 112 among Fig. 4 between frequency-domain transform unit 111 and extending bandwidth spectrum coding unit 114.Spectrum modifying unit 112 in the embodiment 1 carries out the dynamic range that various distortion change first frequency spectrum with the first frequency spectrum S1 (k), thereby investigation and is encoded this deformation information and exported as the deformation method of appropriate dynamic range.On the other hand, 3 of present embodiments are carried out the estimation of this deformation information based on coding side and the shared information of decoding end, and carry out the distortion of the first frequency spectrum S1 (k) according to this estimation deformation information.

Therefore, present embodiment 3 has dynamic range computing unit 302, deformation information estimation unit 303 and replaces spectrum modifying unit 112 according to the deformation unit 304 that this estimation deformation information carries out the first frequency spectrum S1 (k) distortion.In addition, deformation information by in the spectrum coding unit and the estimation carried out respectively of the inside of frequency spectrum decoding unit obtain, need not deformation information to be exported as coded identification, therefore need not the Multiplexing Unit 115 that in the spectrum coding unit 106 of Fig. 4, is provided with by spectrum coding unit 301.

By the frequency-domain transform unit 111 outputs first frequency spectrum S1 (k), offer dynamic range computing unit 302 and deformation unit 304.Dynamic range computing unit 302 quantizes the dynamic range of the first frequency spectrum S1 (k), and its result is exported as dynamic range information.Same with embodiment 1, the method for quantification dynamic range is divided into a plurality of subbands with the frequency domain of first frequency spectrum, obtains the power (subband power) of the subband of specialized range, calculates the variance of this subband power, and this variance is exported as dynamic range information.

Next, use Figure 15 that deformation information estimation unit 303 is described.Deformation information estimation unit 303 is from by dynamic range computing unit 302 input dynamic range information, and offers switch unit 305.Switch unit 305 is based on described dynamic range information, selects 1 to estimate deformation information and output from the candidate of the estimation deformation information that is stored in deformation information form 306.Writing down the candidate of a plurality of estimation deformation informations of the value of getting between 0～1 in the deformation information form 306, these candidates pre-determine by study, with corresponding to dynamic range information.

Figure 16 is the block scheme of the primary structure of expression deformation unit 304.The module that has same names and identical numbering with Fig. 6 has identical functions, therefore omits its explanation.Exponential quantity computing unit 307 in the deformation unit 304 of Figure 16 is according to the estimation deformation information that is provided by deformation information estimation unit 303 (getting the value between 0～1), will be by the exponential quantity of the absolute amplitude of the frequency spectrum of absolute value calculation unit 132 output, promptly by estimating that deformation information carries out the value of power, outputs to positive sign/negative sign and gives unit 134.Positive sign/negative sign is given unit 134, to the exponential quantity of exponential quantity computing unit 307 outputs, gives by positive sign/negative sign extraction unit 131 in the symbolic information of before having obtained, as the output of distortion first frequency spectrum.

As mentioned above, code device (spectrum coding unit 301) according to present embodiment, first frequency spectrum that use is obtained by first signal (0≤k＜FL), second frequency spectrum that estimation is obtained from secondary signal (HFS of 0≤k＜FH) (FL≤k＜FH), and when estimated information encoded, directly do not use first frequency spectrum but carry out above-mentioned estimation again after first frequency spectrum applied distortion, the dynamic range that can adjust estimated spectral thus rightly improves the subjective quality of decoded signal.At this moment, for the information of representing how to be out of shape (deformation information), because based on determining deformation information in decoding end, the shared information (being first frequency spectrum in the present embodiment) of coding side, so need not the coded identification of relevant deformation information is transferred to decoding device, therefore can reduce bit rate.

In addition, in the deformation information estimation unit 303, also can use dynamic range information with first frequency spectrum as input value, to estimate the mapping function of deformation information, and replace utilizing deformation information form 306 and set up the dynamic range information and the corresponding relation of estimating deformation information of first frequency spectrum as output valve.At this moment, the estimation deformation information as the function output valve limits the value of getting between 0～1.

Figure 17 is the block scheme of primary structure of the frequency spectrum decoding unit 353 of expression present embodiment 3.In this structure, the module that has same names and identical numbering with Figure 10 has identical functions, therefore omits its explanation.Between frequency-domain transform unit 164 and extending bandwidth frequency spectrum generation unit 163, have dynamic range computing unit 361, deformation information estimation unit 362 and deformation unit 363.Deformation unit 162 among Figure 10 is imported the deformation information by spectrum modifying unit 112 generations of coding side, and based on this deformation information the first frequency spectrum S1 (k) that is provided by frequency-domain transform unit 164 is applied distortion.With respect to this, 3 of present embodiments are identical with above-mentioned spectrum coding unit 301: carry out the estimation of this deformation information based on the shared information of coding side and decoding end, and carry out the distortion of the first frequency spectrum S1 (k) according to this estimation deformation information.

Therefore, present embodiment 3 has dynamic range computing unit 361, deformation information estimation unit 362 and deformation unit 363.In addition, identical with above-mentioned spectrum coding unit 301, deformation information is obtained by the estimation of carrying out in the inside of frequency spectrum decoding unit, does not comprise deformation information in the coded identification of input, therefore need not the separative element that is arranged at frequency spectrum decoding unit 153 161 among Figure 10.

By the frequency-domain transform unit 164 outputs first frequency spectrum S1 (k), offer dynamic range computing unit 361 and deformation unit 363.The ensuing operation of relevant dynamic range computing unit 361, deformation information estimation unit 362 and deformation unit 363, dynamic range computing unit 302, deformation information estimation unit 303 and the deformation unit 304 interior with the spectrum coding unit 301 (with reference to Figure 14) of the coding side that had illustrated already are identical, therefore omit its explanation.In addition, the deformation information charting in the deformation information estimation unit 362 with spectrum coding unit 301 in deformation information estimation unit 303 in the candidate of the identical estimation deformation information of deformation information form 306.

In addition, the operation that constitutes unit 165 and spatial transform unit 166 about extending bandwidth frequency spectrum generation unit 163, frequency spectrum is identical with Figure 10 signal of embodiment 1, and omission is to its explanation.

As mentioned above, decoding device (frequency spectrum decoding unit 353) according to present embodiment, can be to decoding by the code device encoded signals of present embodiment, the dynamic range that can adjust estimated spectral thus rightly improves the subjective quality of decoded signal.

In addition, in the present embodiment, the estimation deformation information is obtained by deformation information estimation unit 303, but also this estimation deformation information can be applicable to the spectrum coding unit 106 of Fig. 4 signal of embodiment 1, and should estimate that deformation information offered spectrum modifying unit 112, the estimation deformation information that spectrum modifying unit 112 will be provided by deformation information estimation unit 303 is as benchmark, near it deformation information is chosen from index variable form 135, and from the deformation information of this qualification, determine the most appropriate deformation information by search unit 125.In this structure, the coded identification of final selected deformation information is expressed as for the relative value as the estimation deformation information of said reference.So can correct deformation information be encoded and to the decoding unit transmission, therefore can access the effect that the bit number of deformation information is represented in the subjective quality of keeping decoded signal and minimizing.

(embodiment 4)

In the embodiments of the present invention 4,, determine to export to the estimation deformation information of the deformation unit in the spectrum coding unit based on the pitch gain that has the ground floor coding unit to provide.

Figure 18 is the block scheme of primary structure of the hierarchy encoding apparatus 400 of expression present embodiment.In Figure 18, the module that has same names and identical numbering with Fig. 3 has identical functions, therefore omits its explanation.

Hierarchy encoding apparatus 400 in the present embodiment 4 will be offered spectrum coding unit 406 by the pitch gain that ground floor coding unit 402 is obtained.Specifically, in ground floor coding unit 402, the adaptive code vector gain of being taken advantage of on the adaptive code vector of being exported by ground floor coding unit 402 intrinsic adaptive codebook (not shown)s as pitch gain output, and inputs to spectrum coding unit 406.This adaptive code vector gain has periodicity when input signal and gets big value, the characteristics that get the small value when time a little less than the periodicity of input signal when strong.Figure 19 is the block scheme of primary structure of the spectrum coding apparatus 406 of expression present embodiment 4.In Figure 19, the module that has same names and identical numbering with Figure 14 has identical functions, therefore omits its explanation.Deformation information estimation unit 411 uses the pitch gain that is provided by ground floor coding unit 402 to export the estimation deformation information.Deformation information estimation unit 411 has the identical structure of deformation information estimation unit 303 of above-mentioned Figure 15.But, the deformation information form is a corresponding pitch gain and designing.In addition, in the present embodiment, also can adopt the structure of utilizing mapping function to replace utilizing the structure of deformation information form.

As mentioned above,, can consider the periodicity of input signal and adjust the dynamic range of estimated spectral rightly, improve the subjective quality of decoded signal according to the code device (spectrum coding unit 406) of present embodiment.

Next, describe the structure of hierarchical decoding device 450 in detail, this decoding device can be decoded to the coded identification that is generated by above-mentioned hierarchy encoding apparatus 400.

Figure 20 is the block scheme of primary structure of the hierarchical decoding device 450 of expression present embodiment.In Figure 20, the pitch gain of being exported by ground floor decoding unit 452 offers frequency spectrum decoding unit 453.In ground floor decoding unit 452, the adaptive code vector gain of being taken advantage of on the adaptive code vector of being exported by ground floor decoding unit 452 intrinsic adaptive codebook (not shown)s as pitch gain output, and inputs to frequency spectrum decoding unit 453.

Figure 21 is the block scheme of primary structure of the frequency spectrum decoding unit 453 of expression present embodiment 4.Deformation information estimation unit 461 uses the pitch gain that is provided by ground floor decoding unit 452 to export the estimation deformation information.Deformation information estimation unit 461 has in the identical structure of the deformation information estimation unit 303 of above-mentioned Figure 15.But, the same in deformation information form and the deformation information estimation unit 411, corresponding pitch gain and designing.In addition, in the present embodiment, also can adopt the structure of utilizing mapping function to replace utilizing the structure of deformation information form.

As mentioned above, decoding device (frequency spectrum decoding unit 453) according to present embodiment, can be to decoding by the code device encoded signals of present embodiment, and can consider the periodicity of input signal and adjust the dynamic range of estimated spectral rightly, improve the subjective quality of decoded signal.

In addition, also can adopt and use pitch period (delay that the result by adaptive codebook intrinsic in the search ground floor coding unit 402 obtains) simultaneously except pitch gain and estimate the structure of deformation information.At this moment, by utilizing pitch period, can carry out respectively estimation, thereby improve the accuracy of estimating the appropriate deformation information of the long voice (such as sound of the male sex) of the short voice (such as sound of women) of pitch period and pitch period.

In addition, in the present embodiment, the estimation deformation information is obtained by deformation information estimation unit 411, but also can be identical: will estimate that deformation information is applicable to the spectrum coding unit 106 of Fig. 4 signal of embodiment 1 with embodiment 3, and should estimate that deformation information offered spectrum modifying unit 112, the estimation deformation information that spectrum modifying unit 112 will be provided by deformation information estimation unit 411 is as benchmark, near it deformation information is chosen from index variable form 135, and from the deformation information of this qualification, determine the most appropriate deformation information by search unit 125.In this structure, the coded identification of final selected deformation information is expressed as for the relative value as the estimation deformation information of said reference.So can encode and to decoding unit transmission, therefore can access the subjective quality of keeping decoded signal and reduce the effect of the bit number of expression deformation information correct deformation information.

(embodiment 5)

In the embodiments of the present invention 5,, determine to output to the estimation deformation information of the deformation unit in the spectrum coding unit based on the LPC coefficient that provides by the ground floor coding unit.

The structure of the hierarchy encoding apparatus of present embodiment 5 is the same with above-mentioned Figure 18.But, the parameter of exporting to spectrum coding unit 406 by ground floor coding unit 402 is LPC coefficient rather than pitch gain.

The primary structure of the spectrum coding unit 406 of embodiment is a structure as shown in figure 22.Be that with the difference of above-mentioned Figure 19 the parameter that offers deformation information estimation unit 511 is the structure of LPC coefficient rather than pitch gain and deformation information estimation unit 511 inside.

Figure 23 is the block scheme of primary structure of the deformation information estimation unit 511 of expression present embodiment.Deformation information estimation unit 511 comprises: judge form 512, similar degree judging unit 513, deformation information form 514 and switch unit 515.Deformation information form 306 among deformation information form 514 and Figure 15 is similarly writing down the candidate of estimating deformation information.But, the candidate of this estimation deformation information is a corresponding LPC coefficient and designing.Judge the candidate that is writing down the LPC coefficient in the form 512, judge that form 512 is provided with mutual corresponding relation with deformation information form 514.Just, when selecting the candidate of the individual LPC coefficient of j from judge form 512, the estimation deformation information that is suitable for this LPC coefficient candidate is stored as j of deformation information form 514.The LPC coefficient has the advantages that the enough less parameters of energy show the profile (spectrum envelope) of frequency spectrum exactly, the estimation deformation information of this frequency spectrum profiles with the control dynamic range can be mapped.Present embodiment has adopted the structure of utilizing these characteristics.

Similarity degree judging unit 513 is obtained the most similar LPC coefficient of LPC coefficient that provides to ground floor coding unit 402 from judge form 512.During this similarity degree is judged, by judging form 512, obtaining the distance (distortion) between the LPC coefficient or obtaining the LPC transformation of coefficient is both distortion after other the parameter of LSP (LineSpectrum Pair) coefficient etc., and obtains and make this distortion be hour LPC coefficient.

The index of the LPC coefficient candidate in the judgement form 512 when expression makes distortion be minimum (being the similarity degree maximum) by 513 outputs of similarity degree judging unit, and offers switch unit 515.The candidate of the estimation deformation information that switch unit 515 these index of selection are represented, and by 511 outputs of deformation information estimation unit.

As mentioned above,, can consider the frequency spectrum profiles of input signal and adjust the dynamic range of estimated spectral rightly, improve the subjective quality of decoded signal according to the code device (spectrum coding unit 406) of present embodiment.

Next, the structure of the hierarchical decoding device of present embodiment 5 is described, the coded identification that this decoding device can generate the hierarchy encoding apparatus by present embodiment 5 is decoded.

The structure of the hierarchical decoding device of present embodiment 5 is the same with above-mentioned Figure 20.But, the parameter of exporting to frequency spectrum decoding unit 453 by ground floor decoding unit 452 is LPC coefficient rather than pitch gain.

The primary structure of the frequency spectrum decoding unit 453 of embodiment as shown in figure 24.Be that with the difference of above-mentioned Figure 21 the parameter that offers deformation information estimation unit 561 is the structure of LPC coefficient rather than pitch gain and deformation information estimation unit 561 inside.

The structure of deformation information estimation unit 561 inside, with the deformation information estimation unit 511 in the spectrum coding unit 406 among Figure 22, be shown in Figure 23 identical, being stored in the information of judging form 512 and deformation information form 514 also is that coding side and decoding end are shared.

As mentioned above, decoding device (frequency spectrum decoding unit 453) according to present embodiment, can be to decoding by the code device encoded signals of present embodiment, and can consider the frequency spectrum profiles of input signal and adjust the dynamic range of estimated spectral rightly, thereby improve the subjective quality of decoded signal.

In addition, in the present embodiment, the estimation deformation information is obtained by deformation information estimation unit 511, but also can be identical: will estimate that deformation information is applicable to the spectrum coding unit 106 of Fig. 4 signal of embodiment 1 with embodiment 4, and should estimate that deformation information offered spectrum modifying unit 112, the estimation deformation information that spectrum modifying unit 112 will be provided by deformation information estimation unit 511 is as benchmark, from index variable form 135, select near the deformation information it, and from the deformation information of this qualification, determine the most appropriate deformation informations by search unit 125.In this structure, the coded identification of final selected deformation information is expressed as for the relative value as the estimation deformation information of said reference.So can encode and to decoding unit transmission, therefore can access the subjective quality of keeping decoded signal and reduce the effect of the bit number of expression deformation information correct deformation information.

(embodiment 6)

The basic structure of the hierarchy encoding apparatus of embodiments of the present invention 6 is the same with the hierarchy encoding apparatus shown in the embodiment 1, so omit its explanation, below only the spectrum modifying unit 612 different with the structure of spectrum modifying unit 112 is described.

Spectrum modifying unit 612 puts on the first frequency spectrum S1 (k) with following distortion, and (0≤k＜FL) makes the dynamic range of the first frequency spectrum S1 (k) approach the HFS (dynamic range of FL≤k＜FH) of the second frequency spectrum S2 (k).The deformation information of 612 pairs of relevant these distortion in spectrum modifying unit is encoded and is exported.

Figure 25 is the figure that is used to illustrate the spectrum modifying method of present embodiment.

The figure shows the distribution of the amplitude of the first frequency spectrum S1 (k).The first frequency spectrum S1 (k) demonstrates (the different amplitude of value of 0≤k＜FL) because of frequency k.So if transverse axis is got amplitude, the longitudinal axis is got the probability that this amplitude occurs, then as shown in the figure, the mean value ml that occurs with amplitude is the distribution of the similar normal distribution at center.

In the present embodiment, should the distribution rough segmentation be nearer group of range averaging value ml (area B among the figure) and range averaging value ml group (the regional A among the figure) far away at first.Next, obtain the typical value of this amplitude of two groups, specifically, obtain the frequency spectrum that is contained in regional A amplitude mean value and be contained in the mean value of amplitude of the frequency spectrum of area B.At this, amplitude uses will be established mean value ml and be made as zero and the absolute value (deducting mean value ml from each value) of amplitude when converting.For example, regional A is by big the constituting with two little zones of amplitude ratio mean value ml of amplitude ratio mean value ml, is zero processing that converts by establishing mean value ml, and the absolute value of amplitude that then is contained in the frequency spectrum in two zones has identical value.Therefore, the mean value of regional A for example, the typical value that is equivalent to the bigger frequency spectrum of amplitude (absolute value) after converting in first frequency spectrum is converged into an amplitude of organizing and will organizing is calculated; The mean value of area B is equivalent to that the smaller frequency spectrum of amplitude (absolute value) after converting in first frequency spectrum converged into a group and the typical value of the amplitude that will organize is calculated.Thus, these two typical values are for briefly showing the parameter of the dynamic range of first frequency spectrum.

Next in present embodiment, carries out and the identical processing that first frequency spectrum is carried out second frequency spectrum, and obtains the typical value corresponding to each group of second frequency spectrum.Next, the ratio of typical value and the typical value of second frequency spectrum of obtaining first frequency spectrum of regional A (specifically is, the typical value of second frequency spectrum is to the ratio of the typical value of first frequency spectrum), and the ratio of typical value and the typical value of second frequency spectrum of obtaining first frequency spectrum of area B.Therefore, can calculate the ratio of dynamic range with the dynamic range of second frequency spectrum of first frequency spectrum roughly.The spectrum modifying unit of present embodiment likens this for the deformation information of frequency spectrum to encodes and export.

Figure 26 is the block scheme of the primary structure of expression 612 inside, spectrum modifying unit.

Spectrum modifying unit 612 roughly is divided into: above-mentioned each group to first frequency spectrum is carried out the system that typical value is calculated; Above-mentioned each group to second frequency spectrum is carried out the system that typical value is calculated; Based on these two typical values that system-computed is come out, determine the deformation information determining unit 626 of deformation information; And, generate the distortion frequency spectrum generation unit 627 that is out of shape frequency spectrum based on this deformation information.

Calculate the system of the typical value of first frequency spectrum, specifically, comprising: extent of deviation computing unit 621-1, first threshold setup unit 622-1, the second threshold setting unit 622-1, the first average frequency spectrum computing unit 624-1 and the second average frequency spectrum computing unit 625-1.Calculate the system of the typical value of second frequency spectrum, the system with the typical value of calculating first frequency spectrum has identical structure basically, structure identical among the figure is compiled is gone up identical numbering, the difference of the branch of numbering back number expression disposal system.And omit its explanation for identical textural element.

Extent of deviation computing unit 621-1 is according to the distribution of amplitudes of the first frequency spectrum S1 (k) of input, calculates " extent of deviation " with the mean value ml of first frequency spectrum, and outputs to the first threshold setup unit 622-1 and the second threshold setting unit 623-1." extent of deviation " specifically is the standard deviation 1 of the distribution of amplitudes of first frequency spectrum.

First threshold setup unit 622-1 utilizes the standard deviation 1 of first frequency spectrum of being obtained by deviation calculation unit 621-1 to obtain first threshold TH1.Being meant the threshold value that is used for specifying the bigger frequency spectrum of the absolute amplitude that is contained in above-mentioned zone A in first frequency spectrum at this first threshold TH1, is the value that standard deviation 1 is multiplied by predetermined constant a.

The operation of the second threshold setting unit 623-1 is identical with the operation of first threshold setup unit 622-1, the second threshold value TH2 that obtains is meant the threshold value that is used for specifying the smaller frequency spectrum of the absolute amplitude that is contained in area B in first frequency spectrum, is standard deviation 1 is multiplied by predetermined constant b (＜a) value.

The first average frequency spectrum computing unit 624-1 obtains the frequency spectrum that is positioned at the first threshold TH1 outside, promptly is contained in the mean value (hereinafter referred to as first mean value) of amplitude of the frequency spectrum of regional A, and outputs to deformation information determining unit 626.

Specifically, the first average frequency spectrum computing unit 624-1 adds that with the amplitude (but being the value before converting) and the mean value ml of first frequency spectrum of the frequency spectrum of each subband of first frequency spectrum value (ml+TH1) of first threshold TH1 compares, and specifies to have the frequency spectrum (step 1) of the amplitude also bigger than this value.Next, the first average frequency spectrum computing unit 624-1 compares the value (ml-TH1) that the mean value ml of the amplitude of the frequency spectrum of each subband of first frequency spectrum and first frequency spectrum deducts first threshold TH1, specifies the frequency spectrum (step 2) with amplitude also littler than this value.Then, it is zero conversion that the amplitude of the frequency spectrum obtained by step 1 and step 2 is carried out the above-mentioned mean value ml that establishes, and obtains the average absolute of the scaled value that obtains, and outputs to deformation information determining unit 626.

The second average frequency spectrum computing unit 625-1 obtains the frequency spectrum that is positioned at the second threshold value TH2 inboard, promptly is contained in the mean value (hereinafter referred to as second mean value) of amplitude of the frequency spectrum of area B, and outputs to deformation information determining unit 626.Concrete operation is identical with the first average frequency spectrum computing unit 624-1.

First mean value that above-mentioned processing is obtained and second mean value are the regional A of first frequency spectrum and the typical value of area B.

The processing of typical value of obtaining second frequency spectrum is same as described above basically.But, first frequency spectrum is different frequency spectrums with second frequency spectrum, is the value that is multiplied by predetermined constant c on the standard deviation 1 of second frequency spectrum so be equivalent to the 3rd threshold value TH3 of first threshold TH1; The 4th threshold value TH4 that is equivalent to the second threshold value TH2 is for being multiplied by predetermined constant d (＜c) value on the standard deviation 1 of second frequency spectrum.

Second mean value that deformation information determining unit 626 utilizes first mean value that obtained by the first average frequency spectrum computing unit 624-1, obtained by the second average frequency spectrum computing unit 625-1, the 3rd mean value that is obtained by the 3rd average frequency spectrum computing unit 624-2 and Siping City's average that is obtained by the equal frequency spectrum computing unit 625-2 of Siping City are determined deformation information as shown below.

That is, deformation information determining unit 626 is calculated the ratio (hereinafter referred to as first gain) of first mean value and the 3rd mean value, and the ratio of the 3rd mean value Siping City average (hereinafter referred to as second gain).Then, because deformation information determining unit 626 has the data form of a plurality of coding candidates of storing deformation information in advance in inside, first gain and second gain are compared with these coding candidates, select the most similar coding candidate, and will represent that the index of this coding candidate exports as deformation information.And distortion frequency spectrum generation unit 627 also delivered in this index.

The first threshold TH1 that distortion frequency spectrum generation unit 627 utilizes first frequency spectrum as input signal, obtained by first threshold setup unit 622-1, the second threshold value TH2 that obtains by the second threshold setting unit 623-1 and by the deformation information of deformation information determining unit 626 outputs, carry out the deformation process of first frequency spectrum, and the distortion frequency spectrum that will generate output.

Figure 27, Figure 28 are the figure that is used to illustrate the generation method of being out of shape frequency spectrum.

Distortion frequency spectrum generation unit 627 utilizes deformation information, calculates the decode value (hereinafter referred to as decoding first gain) of first mean value and the ratio of the 3rd mean value, and the decode value (hereinafter referred to as decoding second gain) of second mean value and the ratio of Siping City's average.These corresponding relations as shown in figure 27.

Next, distortion frequency spectrum generation unit 627 is specified the frequency spectrum that belongs to regional A by comparing the amplitude and the first threshold TH1 of first frequency spectrum, and these frequency spectrums are multiplied by decoding first gain.Similarly, distortion frequency spectrum generation unit 627 is specified the frequency spectrum that belongs to area B by comparing the amplitude and the second threshold value TH2 of first frequency spectrum, and these frequency spectrums are multiplied by decoding second gain.

On the other hand, as shown in figure 28, in first frequency spectrum, there is not coded message in the frequency spectrum under the zone (hereinafter referred to as zone C) that is clipped between the first threshold TH1 and the second threshold value TH2.So distortion frequency spectrum generation unit 627 uses the gain of the central value with decoding first gain and decoding second gain.For example, as shown in figure 28,, obtain the decoding gain y of corresponding certain amplitude x, and the amplitude that this gain is multiplied by first frequency spectrum is got final product according to family curve based on decoding first gain, decoding second gain, first threshold TH1 and the second threshold value TH2.Just, decoding gain y is the linear interpolation of decoding first gain and second gain of decoding.

Figure 29 is the block scheme of primary structure that expression is used for 662 inside, spectrum modifying unit of decoding device.In addition, this spectrum modifying unit 662 is corresponding to the deformation unit 162 shown in the embodiment 1.

Because basic operation is identical with above-mentioned spectrum modifying unit 612, omit its detailed description.662 of this spectrum modifying unit are process object with first frequency spectrum, so disposal system is one.

As mentioned above,, grasp the distribution of the amplitude of the distribution of amplitude of first frequency spectrum and second frequency spectrum respectively, be divided into bigger group of absolute amplitude and the smaller group of absolute amplitude, and obtain the typical value of the amplitude of each group according to present embodiment.And, by obtaining the respectively ratio of the typical value of the amplitude of group of first frequency spectrum and second frequency spectrum, obtain the ratio of the dynamic range between first frequency spectrum and second frequency spectrum, promptly obtain the deformation information of frequency spectrum, and it is encoded.Thus, need not to use the big function of calculated amount as exponential function and obtain deformation information.

In addition, according to present embodiment, utilize the distribution of the amplitude of first frequency spectrum and second frequency spectrum to obtain standard deviation, and obtain first threshold～the 4th threshold value based on this standard deviation.Set threshold value thus, therefore can improve the coding degree of accuracy of deformation information based on the frequency spectrum of reality.

In addition, according to present embodiment, utilize decoding first gain and second gain of decoding to the adjustment that gains of first frequency spectrum, control the dynamic range of first frequency spectrum thus.And, determine decoding first gain and second gain of decoding, so that first frequency spectrum is near the HFS of second frequency spectrum.Therefore, the dynamic range of first frequency spectrum is near the dynamic range of the HFS of second frequency spectrum.And decoding first gain and second Calculation of Gain of decoding need not to use the big function of calculated amount as exponential function.

In addition, present embodiment is that example is illustrated with the big situation of first ratio of gains decoding, second gain of decoding, and according to the character of voice signal, the big situation of decoding second ratio of gains decoding first gain is arranged also.Just, the HFS dynamic range of second frequency spectrum situation bigger than the dynamic range of first frequency spectrum.Such phenomenon many input voice messaging for as take place during fricative sound.Also can be suitable for the spectrum modifying method of present embodiment in this situation.

In addition, in the present embodiment, frequency spectrum is divided into the bigger group of absolute amplitude and less two groups of group of absolute amplitude, and is that example is illustrated, but, also can be divided into more group in order to improve the repeatability of dynamic range with this situation.

In addition, in the present embodiment, with mean value as the benchmark amplitude that converts, and frequency spectrum is divided into bigger group of amplitude ratio and the less group of amplitude ratio based on the amplitude after this conversion, and be that example is illustrated with this situation, but directly use original amplitude, and frequency spectrum is divided into groups also passable based on this amplitude.

In addition, in the present embodiment, use standard deviation to calculate the deviation of the absolute amplitude of frequency spectrum, and be that example is illustrated, be limited to this, for example as also utilizing variance with the same statistical parameter of standard deviation but have more than with this situation.

In addition, in the present embodiment, the mean value of absolute amplitude of frequency spectrum that uses each group is as the typical value of the spectral amplitude of each group, and is that example is illustrated with this situation, be limited to this but have more than, for example also can utilize the central value of the absolute amplitude of each frequency spectrum of organizing.

In addition, in the present embodiment, the situation of adjusting dynamic range with the amplitude that uses each frequency spectrum is illustrated as example, but also can use the performance number of frequency spectrum to replace amplitude.

In addition, obtaining during typical value of corresponding each group, for example as the MDCT coefficient, when the amplitude of frequency spectrum from the beginning just just has or during the symbol born, need not mean value is scaled zero, respectively organize pairing typical value as long as utilize the absolute value of the amplitude of frequency spectrum to obtain.

More than, each embodiment of the present invention has been described.

Code device of the present invention and decoding device are not limited by the respective embodiments described above, and various changes are implemented in addition.

Code device of the present invention and decoding device can be disposed at the communication terminal and the base station apparatus of mobile communications system, and can provide communication terminal and the base station apparatus with same purpose effect with this.

In addition, in this measure the present invention is applicable to that the example of scalable coding mode illustrates, the present invention can also be applicable to other coded system.

In addition, in this measure constitute example of the present invention by hardware and illustrate that the present invention can also realize by software.For example, pass through programming language, algorithm to coding method of the present invention (coding/decoding method) is recorded and narrated, and preserves this program and carry out by signal conditioning package in internal memory, thereby can realize and code device of the present invention (decoding device) identical functions.

In addition, each above-mentioned functional module is typically realized by integrated circuit LSI (large scale integrated circuit).These both can carry out single chip respectively, also can comprise wherein a part of or whole and the implementation single chip.

In addition, though be called LSI, also can be called IC (integrated circuit), system LSI (system lsi), super LSI (VLSI (very large scale integrated circuit)), very big LSI (great scale integrated circuit) according to the difference of integrated level at this.

In addition, the technology of integrated circuit is not only limited to LSI, can use special circuit or general processor to realize yet.FPGA (the Field ProgrammableGate Array that can programme after also can utilizing LSI to make, field programmable gate array), maybe can utilize and the circuit block of LSI inside connected or set the reconfigurable processor (Reconfigurable Processor) that reconfigures.

Have again,, the technology of LSI integrated circuit occurred replacing, can certainly utilize this technology to realize the integrated of functional block if along with the progress of semiconductor technology or the derivation of other technologies.The possibility that also has applied bioengineering to learn a skill etc.

This instructions is willing to the special 2005-133729 of hope of the Jap.P. that the Jap.P. spy is willing to 2004-322953 number and on April 28th, 2005 applied for of 2004-145425, application on November 5th, 2004 according to the Jap.P. spy of application on May 14th, 2004.This content all is included in this as a reference.

Industrial applicibility

The method of code device of the present invention, decoding device and coding/decoding can be applicable to can expand volume Code/decoding etc.

Claims (27)

1. code device comprises:

Coding unit is partly encoded to the high frequency spectrum of input signal; And

Limiting unit is decoded and is obtained first low-frequency spectra the coded signal of the low-frequency spectra of described input signal part, and the amplitude that as one man limits this first low-frequency spectra generates second low-frequency spectra,

Wherein, described coding unit carries out the coding of described high frequency spectrum part based on described second low-frequency spectra.

2. code device as claimed in claim 1 also comprises: transmitting element, one also send about the information of the ways to restrain that is used for described limiting unit and the coded message that obtains by described coding unit.

3. code device as claimed in claim 1, wherein, described limiting unit as one man limits the amplitude of described first low-frequency spectra, so that the average amplitude of fluctuation of the amplitude of the average amplitude of fluctuation of the amplitude of described second low-frequency spectra and described high frequency spectrum part is equal.

4. code device as claimed in claim 1, wherein, the predetermined value in the scope of described limiting unit use from 0 to 1 is as one man carried out power to the amplitude of described first low-frequency spectra, generates described second low-frequency spectra thus.

5. code device as claimed in claim 1, wherein, described coding unit comprises:

Pitch filter is held described second low-frequency spectra as internal state; And

Estimation unit utilizes described pitch filter to estimate described high frequency spectrum part,

Wherein, encode the characteristic of described pitch filter with estimated result corresponding to described estimation unit.

6. code device as claimed in claim 5, wherein, the characteristic of described pitch filter is represented by following transport function:

$P\left(z\right)=\frac{1}{1-z^{-T}}$

Wherein: P (z) is the transport function of pitch filter,

Z is the z conversion coefficient,

T is a retardation coefficient.

7. code device as claimed in claim 1, wherein, described limiting unit is estimated the information of relevant ways to restrain based on described first low-frequency spectra, and utilizes the information that estimates to generate described second low-frequency spectra.

8. code device as claimed in claim 7, wherein, described limiting unit comprises:

The dynamic range computing unit utilizes described first low-frequency spectra to obtain dynamic range information;

The deformation information estimation unit utilizes described dynamic range information to estimate to be used for as one man the deformation information that the amplitude to described first low-frequency spectra limits; And

Deformation unit, the described deformation information that utilization estimates carries out the consistance restriction to the amplitude of described first low-frequency spectra.

9. code device as claimed in claim 7, wherein, described limiting unit comprises:

The deformation information estimation unit utilizes the periodic tone information of the described input signal of expression to estimate to be used for as one man the deformation information that the amplitude to described first low-frequency spectra limits; And

Deformation unit utilizes the described deformation information that estimates as one man the amplitude of described first low-frequency spectra to be limited.

10. code device as claimed in claim 9, described tone information is made of in pitch gain and the pitch period at least one.

11. code device as claimed in claim 7, wherein, described limiting unit comprises:

The deformation information estimation unit utilizes the frequency spectrum profiles information of described input signal to estimate to be used for as one man the deformation information that the amplitude to described first low-frequency spectra limits; And

Deformation unit utilizes the described deformation information that estimates as one man the amplitude of described first low-frequency spectra to be limited.

12. code device as claimed in claim 11, wherein, described deformation information estimation unit comprises:

The frequency spectrum profiles information memory cell is stored the candidate of a plurality of frequency spectrum profiles information; And

The dynamic range information storage unit is stored the candidate of a plurality of dynamic range information,

Wherein, from described frequency spectrum profiles information memory cell, select candidate corresponding to the frequency spectrum profiles information of the frequency spectrum profiles information of described input signal, and

Estimate described deformation information by selection from described dynamic range information storage unit corresponding to the candidate of the dynamic range information of the candidate of the described frequency spectrum profiles information of selecting.

13. code device as claimed in claim 1 further comprises:

First grouped element is divided into a plurality of groups according to the difference of amplitude with described first low-frequency spectra;

First generation tabular value acquiring unit obtains the typical value of amplitude of each group of described first low-frequency spectra;

Second grouped element partly is divided into a plurality of groups according to the difference of amplitude with described high frequency spectrum; And

Second generation tabular value acquiring unit obtains the described high frequency spectrum respectively typical value of the amplitude of group partly,

Wherein, described limiting unit is based on the typical value of each group of described first low-frequency spectra and each typical value of organizing of described high frequency spectrum part, and as one man the amplitude to described first low-frequency spectra limits.

14. code device as claimed in claim 13, wherein, described limiting unit is obtained amplitude between described each typical value by carry out linear interpolation for each typical value.

15. code device as claimed in claim 13, wherein, described limiting unit is based on the ratio of the typical value of each group of the typical value of each group of described first low-frequency spectra and described high frequency spectrum part, and the amplitude of described first low-frequency spectra is carried out the consistance restriction.

16. code device as claimed in claim 13, wherein, described first and second generation tabular value acquiring unit obtain mean value or the central value of respectively organizing amplitude.

17. a decoding device comprises:

Converter unit will become frequency-region signal to generate first low-frequency spectra to the decode signal transformation of gained of the coding that is contained in the low-frequency spectra part in the coding that generates by code device;

Decoding unit is decoded to the coding that is contained in the high frequency spectrum part in the coding that generates by described code device; And

Limiting unit according to the spectrum modifying information that is contained in the coding that generates by described code device, as one man limits the amplitude of described first low-frequency spectra and generates second low-frequency spectra,

Wherein, described decoding unit is decoded to the coding of described high frequency spectrum part based on described second low-frequency spectra.

18. a decoding device comprises:

Converter unit will become frequency-region signal to generate first low-frequency spectra to the decode signal transformation of gained of the coding that is contained in the low-frequency spectra part in the coding that generates by code device;

Decoding unit is decoded to the coding that is contained in the high frequency spectrum part in the coding that generates by described code device; And

Limiting unit carries out the consistance restriction and generates second low-frequency spectra the amplitude of described first low-frequency spectra,

Wherein, described limiting unit is estimated the information of relevant ways to restrain based on described first low-frequency spectra, and utilizes the information that estimates to generate described second low-frequency spectra, and

Described decoding unit is decoded to the coding of described high frequency spectrum part based on described second low-frequency spectra.

19. communication terminal that comprises the described code device of claim 1.

20. base station apparatus that comprises the described code device of claim 1.

21. communication terminal that comprises the described decoding device of claim 17.

22. base station apparatus that comprises the described decoding device of claim 17.

23. communication terminal that comprises the described decoding device of claim 18.

24. base station apparatus that comprises the described decoding device of claim 18.

25. a coding method comprises:

Coding step carries out the coding of the high frequency spectrum part of input signal;

Obtaining step is decoded and is obtained first low-frequency spectra the coded signal of the low-frequency spectra of described input signal part; And

Conditioning step carries out the consistance restriction and generates second low-frequency spectra the amplitude of described first low-frequency spectra,

Wherein, described coding step carries out the coding of described high frequency spectrum part based on described second low-frequency spectra.

26. a coding/decoding method comprises:

Shift step will become frequency-region signal to generate first low-frequency spectra to the decode signal transformation of gained of the coding that is contained in the low-frequency spectra part in the coding that generates by code device;

Decoding step is decoded to the coding that is contained in the high frequency spectrum part in the coding that generates by described code device;

Obtaining step obtains the spectrum modifying information that comprises in the coding that generates by described code device; And

Conditioning step as one man limits to generate second low-frequency spectra to the amplitude of described first low-frequency spectra according to described spectrum modifying information,

Wherein, described decoding step is decoded to the coding of described high frequency spectrum part based on described second low-frequency spectra.

27. a coding/decoding method comprises:

Shift step will become frequency-region signal to generate first low-frequency spectra to the decode signal transformation of gained of the coding that is contained in the low-frequency spectra part in the coding that generates by code device;

Decoding step is decoded to the coding that is contained in the high frequency spectrum part in the coding that generates by described code device; And

Conditioning step as one man limits the amplitude of described first low-frequency spectra and generates second low-frequency spectra,

Wherein, described conditioning step is estimated the information of relevant ways to restrain based on described first low-frequency spectra, and utilizes the information that estimates to generate described second low-frequency spectra, and

Described decoding step is decoded to the coding of described high frequency spectrum part based on described second low-frequency spectra.

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